A review of internal combustion engine combustion chamber process studies at NASA Lewis Research Center

Science.gov (United States)

Schock, H. J.

1984-01-01

The performance of internal combustion stratified-charge engines is highly dependent on the in-cylinder fuel-air mixing processes occurring in these engines. Current research concerning the in-cylinder airflow characteristics of rotary and piston engines is presented. Results showing the output of multidimensional models, laser velocimetry measurements and the application of a holographic optical element are described. Models which simulate the four-stroke cycle and seal dynamics of rotary engines are also discussed. Previously announced in STAR as N84-24999

CFD analysis of the scavenging process in marine two-stroke diesel engines

DEFF Research Database (Denmark)

Andersen, Fredrik Herland; Hult, Johan; Nogenmyr, Karl-Johan

2014-01-01

/charge before the subsequent compression stroke. This implies that the scavenging process is integral to engine performance as it influence the initial condition for the combustion process, thus affecting the fuel economy, power output and emission of hazardous gases. Two-stroke diesel engines for marine...

Modelling of Combustion and Pollutant Formation in a Large, Two-Stroke Marine Diesel Engine using Integrated CFD-Skeletal Chemical Mechanism

DEFF Research Database (Denmark)

Pang, Kar Mun; Karvounis, Nikolas; Schramm, Jesper

In this reported work, simulation studies of in-cylinder diesel combustion and pollutant formation processesin a two-stroke, low-speed uniflow-scavenged marine diesel engine are presented. Numerical computation is performed by integrating chemical kinetics into CFD computations. In order...... to minimize the computational runtime, an in-house skeletal n-heptane chemical mechanism is coupled with the CFD model. This surrogate fuel model comprises 89 reactions with 32 species essential to diesel ignition/combustion processes as well as the formation of soot precursors and nitrogen monoxide (NO......). Prior to the marine engine simulation,coupling of the newly developed surrogate fuel model and a revised multi-step soot model [1] is validated on the basis of optical diagnostics measurement obtained at varying ambient pressure levels [2]. It is demonstrated that the variation of ignition delay times...

COMBUSTION SIMULATION IN A SPARK IGNITION ENGINE CYLINDER: EFFECTS OF AIR-FUEL RATIO ON THE COMBUSTION DURATION

Directory of Open Access Journals (Sweden)

Nureddin Dinler

2010-01-01

Full Text Available Combustion is an important subject of internal combustion engine studies. To reduce the air pollution from internal combustion engines and to increase the engine performance, it is required to increase combustion efficiency. In this study, effects of air/fuel ratio were investigated numerically. An axisymmetrical internal combustion engine was modeled in order to simulate in-cylinder engine flow and combustion. Two dimensional transient continuity, momentum, turbulence, energy, and combustion equations were solved. The k-e turbulence model was employed. The fuel mass fraction transport equation was used for modeling of the combustion. For this purpose a computational fluid dynamics code was developed by using the finite volume method with FORTRAN programming code. The moving mesh was utilized to simulate the piston motion. The developed code simulates four strokes of engine continuously. In the case of laminar flow combustion, Arrhenius type combustion equations were employed. In the case of turbulent flow combustion, eddy break-up model was employed. Results were given for rich, stoichiometric, and lean mixtures in contour graphs. Contour graphs showed that lean mixture (l = 1.1 has longer combustion duration.

The realization and analysis of a new thermodynamic cycle for internal combustion engine

Directory of Open Access Journals (Sweden)

Dorić Jovan Ž.

2011-01-01

Full Text Available This paper presents description and thermodynamic analysis of a new thermodynamic cycle. Realization of this new cycle is possible to achieve with valveless internal combustion engine with more complete expansion. The main purpose of this new IC engine is to increase engines’ thermal efficiency. The engine was designed so that the thermodynamic changes of the working fluid are different than in conventional engines. Specific differences are reflected in a more complete expansion of the working fluid (the expansion stroke is larger than compression stroke, valveless gas flowing and complete discharge of residual combustion products from the combustion chamber. In this concept, the movement of the piston is different than in conventional piston mechanisms. The results obtained herein include the efficiency characteristics of irreversible reciprocating new engine cycle which is very similar to Miller cycle. The results show that with this thermodynamic cycle engine has higher efficiency than with the standard Otto cycle. In this article, the patent application material under number 2008/607 at the Intellectual Property Office of the Republic of Serbia was used.

Automatic compression adjusting mechanism for internal combustion engines

Science.gov (United States)

Akkerman, J. W. (Inventor)

1983-01-01

Means for controlling the compression pressure in an internal combustion engine having one or more cylinders and subject to widely varying power output requirements are provided. Received between each crank pin and connecting rod is an eccentric sleeve selectively capable of rotation about the crank pin and/or inside the rod and for latching with the rod to vary the effective length of the connecting rod and thereby the clearance volume of the engine. The eccentric normally rotates inside the connecting rod during the exhaust and intake strokes but a latching pawl carried by the eccentric is movable radially outwardly to latch the rod and eccentric together during the compression and power strokes. A control valve responds to intake manifold pressure to time the supply of hydraulic fluid to move the latch-pawl outwardly, varying the effective rod length to maintain a substantially optimum firing chamber pressure at all intake manifold pressures.

Small Engines as Bottoming Cycle Steam Expanders for Internal Combustion Engines

Directory of Open Access Journals (Sweden)

Rohitha Weerasinghe

2017-01-01

Full Text Available Heat recovery bottoming cycles for internal combustion engines have opened new avenues for research into small steam expanders (Stobart and Weerasinghe, 2006. Dependable data for small steam expanders will allow us to predict their suitability as bottoming cycle engines and the fuel economy achieved by using them as bottoming cycles. Present paper is based on results of experiments carried out on small scale Wankel and two-stroke reciprocating engines as air expanders and as steam expanders. A test facility developed at Sussex used for measurements is comprised of a torque, power and speed measurements, electronic actuation of valves, synchronized data acquisition of pressure, and temperatures of steam and inside of the engines for steam and internal combustion cycles. Results are presented for four engine modes, namely, reciprocating engine in uniflow steam expansion mode and air expansion mode and rotary Wankel engine in steam expansion mode and air expansion mode. The air tests will provide base data for friction and motoring effects whereas steam tests will tell how effective the engines will be in this mode. Results for power, torque, and p-V diagrams are compared to determine the change in performance from air expansion mode to steam expansion mode.

Regeneration in an internal combustion engine: Thermal-hydraulic modeling and analysis

International Nuclear Information System (INIS)

Thyageswaran, Sridhar

2016-01-01

Highlights: • An arrangement is proposed for in-cylinder regeneration in a 4-stroke engine. • Thermodynamic models are formulated for overall cycle analysis. • A design procedure is outlined for micro-channel regenerators. • Partial differential equations are solved for flow inside the regenerator. • Regeneration with lean combustion decreases the idealized cycle efficiency. - Abstract: An arrangement is proposed for a four-stroke internal combustion engine to: (a) recover thermal energy from products of combustion during the exhaust stroke; (b) store that energy as sensible heat in a micro-channel regenerator matrix; and (c) transfer the stored heat to compressed fresh charge that flows through the regenerator during the succeeding mechanical cycle. An extra moveable piston that can be locked at preferred positions and a sequence of valve events enable the regenerator to lose heat to the working fluid during one interval of time but gain heat from the fluid during another interval of time. This paper examines whether or not this scheme for in-cylinder regeneration (ICR) improves the cycle thermal efficiency η I . Models for various thermodynamic processes in the cycle and treatments for unsteady compressible flow and heat transfer inside the regenerator are developed. Digital simulations of the cycle are made. Compared to an idealized engine cycle devoid of regeneration, provisions for ICR seem to deteriorate the thermal efficiency. In an 8:1 compression ratio octane engine simulated with an equivalence ratio of 0.75, η I  = 0.455 with regeneration and η I  = 0.491 without. This study shows that previous claims on efficiency gains via ICR, using highly-simplified models, may be misleading.

The scaling of performance and losses in miniature internal combustion engines

Science.gov (United States)

Menon, Shyam Kumar

Miniature glow ignition internal combustion (IC) piston engines are an off--the--shelf technology that could dramatically increase the endurance of miniature electric power supplies and the range and endurance of small unmanned air vehicles provided their overall thermodynamic efficiencies can be increased to 15% or better. This thesis presents the first comprehensive analysis of small (system is developed that is capable of making reliable measurements of engine performance and losses in these small engines. Methodologies are also developed for measuring volumetric, heat transfer, exhaust, mechanical, and combustion losses. These instruments and techniques are used to investigate the performance of seven single-cylinder, two-stroke, glow fueled engines ranging in size from 15 to 450 g (0.16 to 7.5 cm3 displacement). Scaling rules for power output, overall efficiency, and normalized power are developed from the data. These will be useful to developers of micro-air vehicles and miniature power systems. The data show that the minimum length scale of a thermodynamically viable piston engine based on present technology is approximately 3 mm. Incomplete combustion is the most important challenge as it accounts for 60-70% of total energy losses. Combustion losses are followed in order of importance by heat transfer, sensible enthalpy, and friction. A net heat release analysis based on in-cylinder pressure measurements suggest that a two--stage combustion process occurs at low engine speeds and equivalence ratios close to 1. Different theories based on burning mode and reaction kinetics are proposed to explain the observed results. High speed imaging of the combustion chamber suggests that a turbulent premixed flame with its origin in the vicinity of the glow plug is the primary driver of combustion. Placing miniature IC engines on a turbulent combustion regime diagram shows that they operate in the 'flamelet in eddy' regime whereas conventional--scale engines operate

Heat Transfer in Large Two-Stroke Marine Diesel Engines

DEFF Research Database (Denmark)

Jensen, Michael Vincent

Heat transfer between the cylinder gas and the piston surface during combustion in large two-stroke uniflow scavenged marine diesel engines has been investigated in the present work. The piston surface experiences a severe thermal load during combustion due to the close proximity of the combustion...... zone to the surface. At the same time, cooling of the piston crown is relatively complicated. This can cause large thermal stresses in the piston crown and weakening of the material strength, which may be critical as it can lead to formation of cracks. Information about the piston surface heat transfer...... is thus important for the engine manufactures. The piston surface heat transfer was studied in the event of impingement of hot combustion products on the piston during combustion, and an estimate was obtained of the peak heat flux level experienced on the piston surface. The investigation was carried out...

Large-eddy simulations of turbulent flows in internal combustion engines

Science.gov (United States)

Banaeizadeh, Araz

The two-phase compressible scalar filtered mass density function (FMDF) model is further developed and employed for large-eddy simulations (LES) of turbulent spray combustion in internal combustion (IC) engines. In this model, the filtered compressible Navier-Stokes equations are solved in a generalized curvilinear coordinate system with high-order, multi-block, compact differencing schemes for the turbulent velocity and pressure. However, turbulent mixing and combustion are computed with a new two-phase compressible scalar FMDF model. The spray and droplet dispersion/evaporation are modeled with a Lagrangian method. A new Lagrangian-Eulerian-Lagrangian computational method is employed for solving the flow, spray and scalar equation. The pressure effect in the energy equation, as needed in compressible flows, is included in the FMDF formulation. The performance of the new compressible LES/FMDF model is assessed by simulating the flow field and scalar mixing in a rapid compression machine (RCM), in a shock tube and in a supersonic co-axial jet. Consistency of temperatures predicted by the Eulerian finite-difference (FD) and Lagrangian Monte Carlo (MC) parts of the LES/FMDF model are established by including the pressure on the FMDF. It is shown that the LES/FMDF model is able to correctly capture the scalar mixing in both compressible subsonic and supersonic flows. Using the new two-phase LES/FMDF model, fluid dynamics, heat transfer, spray and combustion in the RCM with flat and crevice piston are studied. It is shown that the temperature distribution in the RCM with crevice piston is more uniform than the RCM with flat piston. The fuel spray characteristics and the spray parameters affecting the fuel mixing inside the RCM in reacting and non-reacting flows are also studied. The predicted liquid penetration and flame lift-off lengths for respectively non-reacting and reacting sprays are found to compare well with the available experimental data. Temperatures and

HERCULES Advanced Combustion Concepts Test Facility: Spray/Combustion Chamber

Energy Technology Data Exchange (ETDEWEB)

Herrmann, K. [Eidgenoessische Technische Hochschule (ETH), Labor fuer Aerothermochemie und Verbrennungssysteme, Zuerich (Switzerland)

2004-07-01

This yearly report for 2004 on behalf of the Swiss Federal Office of Energy (SFOE) at the Laboratory for Aero-thermochemistry and Combustion Systems at the Federal Institute of Technology ETH in Zurich, Switzerland, presents a review of work being done within the framework of HERCULES (High Efficiency R and D on Combustion with Ultra Low Emissions for Ships) - the international R and D project concerning new technologies for ships' diesels. The work involves the use and augmentation of simulation models. These are to be validated using experimental data. The report deals with the development of an experimental set-up that will simulate combustion in large two-stroke diesel engines and allow the generation of reference data. The main element of the test apparatus is a spray / combustion chamber with extensive possibilities for optical observation under variable flow conditions. The results of first simulations confirm concepts and shall help in further work on the project. The potential offered by high-speed camera systems was tested using the institute's existing HTDZ combustion chamber. Further work to be done is reviewed.

Internal Heterogeneous Processes in Aluminum Combustion

Science.gov (United States)

Dreizin, E. L.

1999-01-01

This paper discusses the aluminum particle combustion mechanism which has been expanded by inclusion of gas dissolution processes and ensuing internal phase transformations. This mechanism is proposed based on recent normal and microgravity experiments with particles formed and ignited in a pulsed micro-arc. Recent experimental findings on the three stages observed in Al particle combustion in air and shows the burning particle radiation, trajectory (streak), smoke cloud shapes, and quenched particle interiors are summarized. During stage I, the radiation trace is smooth and the particle flame is spherically symmetric. The temperature measured using a three-color pyrometer is close to 3000 K. Because it exceeds the aluminum boiling point (2730 K), this temperature most likely characterizes the vapor phase flame zone rather than the aluminum surface. The dissolved oxygen content within particles quenched during stage I was below the detection sensitivity (about 1 atomic %) for Wavelength Dispersive Spectroscopy (WDS). After an increase in the radiation intensity (and simultaneous decrease in the measured color temperature from about 3000 to 2800 K) indicative of the transition to stage II combustion, the internal compositions of the quenched particles change. Both oxygen-rich (approx. 10 atomic %) and oxygen-lean (combustion behavior and the evolution of its internal composition, the change from the spherically symmetric to asymmetric flame shape occurring upon the transition from stage I to stage II combustion could not be understood based only on the fact that dissolved oxygen is detected in the particles. The connection between the two phenomena appeared even less significant because in earlier aluminum combustion studies carried in O2/Ar mixtures, flame asymmetry was not observed as opposed to experiments in air or O2/CO mixtures. It has been proposed that the presence of other gases, i.e., hydrogen, or nitrogen causes the change in the combustion regime.

International Survey on the Management of Wake-Up Stroke.

Science.gov (United States)

de Castro-Afonso, Luís Henrique; Nakiri, Guilherme Seizem; Pontes-Neto, Octávio Marques; dos Santos, Antônio Carlos; Abud, Daniel Giansante

2016-01-01

Patients who wake up having experienced a stroke while asleep represent around 20% of acute stroke admissions. According to international guidelines for the management of acute stroke, patients presenting with wake-up stroke are not currently eligible to receive revascularization treatments. In this study, we aimed to assess the opinions of stroke experts about the management of patients with wake-up stroke by using an international multicenter electronic survey. This study consisted of 8 questions on wake-up stroke treatment. Two hundred invitations to participate in the survey were sent by e-mail. Fifty-nine participants started the survey, 4 dropped out before completing it, and 55 completed the full questionnaire. We had 55 participants from 22 countries. In this study, most stroke experts recommended a recanalization treatment for wake-up stroke. However, there was considerable disagreement among experts regarding the best brain imaging method and the best recanalization treatment. The results of ongoing randomized trials on wake-up stroke are urgently needed.

A computational fluid dynamics analysis on stratified scavenging system of medium capacity two-stroke internal combustion engines

Directory of Open Access Journals (Sweden)

Pitta Srinivasa Rao

2008-01-01

Full Text Available The main objective of the present work is to make a computational study of stratified scavenging system in two-stroke medium capacity engines to reduce or to curb the emissions from the two-stroke engines. The 3-D flows within the cylinder are simulated using computational fluid dynamics and the code Fluent 6. Flow structures in the transfer ports and the exhaust port are predicted without the stratification and with the stratification, and are well predicted. The total pressure and velocity map from computation provided comprehensive information on the scavenging and stratification phenomenon. Analysis is carried out for the transfer ports flow and the extra port in the transfer port along with the exhaust port when the piston is moving from the top dead center to the bottom dead center, as the ports are closed, half open, three forth open, and full port opening. An unstructured cell is adopted for meshing the geometry created in CATIA software. Flow is simulated by solving governing equations namely conservation of mass momentum and energy using SIMPLE algorithm. Turbulence is modeled by high Reynolds number version k-e model. Experimental measurements are made for validating the numerical prediction. Good agreement is observed between predicted result and experimental data; that the stratification had significantly reduced the emissions and fuel economy is achieved.

75 FR 75937 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2010-12-07

... National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines... internal combustion engines. Subsequently, the Administrator received two petitions for reconsideration... Any industry using a stationary 2211 Electric power reciprocating internal generation, combustion...

International Survey on the Management of Wake-Up Stroke

Directory of Open Access Journals (Sweden)

Luís Henrique de Castro-Afonso

2016-03-01

Full Text Available Background: Patients who wake up having experienced a stroke while asleep represent around 20% of acute stroke admissions. According to international guidelines for the management of acute stroke, patients presenting with wake-up stroke are not currently eligible to receive revascularization treatments. In this study, we aimed to assess the opinions of stroke experts about the management of patients with wake-up stroke by using an international multicenter electronic survey. Method: This study consisted of 8 questions on wake-up stroke treatment. Results: Two hundred invitations to participate in the survey were sent by e-mail. Fifty-nine participants started the survey, 4 dropped out before completing it, and 55 completed the full questionnaire. We had 55 participants from 22 countries. Conclusions: In this study, most stroke experts recommended a recanalization treatment for wake-up stroke. However, there was considerable disagreement among experts regarding the best brain imaging method and the best recanalization treatment. The results of ongoing randomized trials on wake-up stroke are urgently needed.

Plasma igniter for internal-combustion engines

Science.gov (United States)

Breshears, R. R.; Fitzgerald, D. J.

1978-01-01

Hot ionized gas (plasma) ignites air/fuel mixture in internal combustion engines more effectively than spark. Electromagnetic forces propel plasma into combustion zone. Combustion rate is not limited by flame-front speed.

Low emission internal combustion engine

Science.gov (United States)

Karaba, Albert M.

1979-01-01

A low emission, internal combustion compression ignition engine having a cylinder, a piston movable in the cylinder and a pre-combustion chamber communicating with the cylinder near the top thereof and in which low emissions of NO.sub.x are achieved by constructing the pre-combustion chamber to have a volume of between 70% and 85% of the combined pre-chamber and main combustion chamber volume when the piston is at top dead center and by variably controlling the initiation of fuel injection into the pre-combustion chamber.

Internal combustion engines in hybrid vehicles

NARCIS (Netherlands)

Mourad, S.; Weijer, C.J.T. van de; Beckman, D.E.

1998-01-01

In this paper the use of internal combustion engines in hybrid powertrains is investigated. The substantial difference between the use of internal combustion engines in conventional and in hybrid vehicles mean that engines for hybrid vehicles should be designed specifically for the purpose. At the

30 CFR 56.4103 - Fueling internal combustion engines.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fueling internal combustion engines. 56.4103... Prevention and Control Prohibitions/precautions/housekeeping § 56.4103 Fueling internal combustion engines. Internal combustion engines shall be switched off before refueling if the fuel tanks are integral parts of...

30 CFR 57.4103 - Fueling internal combustion engines.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Fueling internal combustion engines. 57.4103... Prevention and Control Prohibitions/precautions/housekeeping § 57.4103 Fueling internal combustion engines. Internal combustion engines shall be switched off before refueling if the fuel tanks are integral parts of...

30 CFR 77.1105 - Internal combustion engines; fueling.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Internal combustion engines; fueling. 77.1105 Section 77.1105 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... COAL MINES Fire Protection § 77.1105 Internal combustion engines; fueling. Internal combustion engines...

Science review of internal combustion engines

International Nuclear Information System (INIS)

Taylor, Alex M.K.P.

2008-01-01

Internal combustion engines used in transportation produce about 23% of the UK's carbon dioxide emission, up from 14% in 1980. The current science described in this paper suggests that there could be 6-15% improvements in internal combustion fuel efficiency in the coming decade, although filters to meet emission legislation reduce these gains. Using these engines as hybrids with electric motors produces a reduction in energy requirements in the order of 21-28%. Developments beyond the next decade are likely to be dominated by four topics: emission legislation and emission control, new fuels, improved combustion and a range of advanced concepts for energy saving. Emission control is important because current methods for limiting nitrogen oxides and particulate emissions imply extra energy consumption. Of the new fuels, non-conventional fossil-derived fuels are associated with larger greenhouse gas emissions than conventional petroleum-based fuels, while a vehicle propelled by fuel cells consuming non-renewable hydrogen does not necessarily offer an improvement in emissions over the best hybrid internal combustion engines. Improved combustion may be developed for both gasoline and diesel fuels and promises better efficiency as well as lower noxious emissions without the need for filtering. Finally, four advanced concepts are considered: new thermodynamic cycles, a Rankine bottoming cycle, electric turbo-compounding and the use of thermoelectric devices. The latter three all have the common theme of trying to extract energy from waste heat, which represents about 30% of the energy input to an internal combustion engine

Reaction of Sulfuric Acid in Lube Oil: Implications for Large Two-Stroke Diesel Engines

DEFF Research Database (Denmark)

Lejre, Kasper Hartvig; Kiil, Søren; Glarborg, Peter

2017-01-01

Slow-steaming operation and an increased pressure in the combustion chamber have contributed to increased sulfuric acid (H2SO4) condensation on the cylinder liners in large two-stroke marine diesel engines, thus causing increased corrosion wear. To cope with this, lube oils are formulated...... of CaCO3 compared to the condensed H2SO4. The observed corrosion wear in large two-stroke marine diesel engines could consequently be attributed to local molar excess of H2SO4 compared to CaCO3 reverse micelles on the cylinder liners....

The Tracer Gas Method of Determining the Charging Efficiency of Two-stroke-cycle Diesel Engines

Science.gov (United States)

Schweitzer, P H; Deluca, Frank, Jr

1942-01-01

A convenient method has been developed for determining the scavenging efficiency or the charging efficiency of two-stroke-cycle engines. The method consists of introducing a suitable tracer gas into the inlet air of the running engine and measuring chemically its concentration both in the inlet and exhaust gas. Monomethylamine CH(sub 3)NH(sub 2) was found suitable for the purpose as it burns almost completely during combustion, whereas the "short-circuited" portion does not burn at all and can be determined quantitatively in the exhaust. The method was tested both on four-stroke and on two-stroke engines and is considered accurate within 1 percent.

Coherent anti-Stokes Raman spectroscopy temperature measurements in an internal combustion engine

Science.gov (United States)

Ball, Don; Driver, H. Steve T.; Hutcheon, Richard J.; Lockett, Russel J.; Robertson, Gerald N.

1994-09-01

Part of a project to investigate the physics and chemistry of alternative fuels in internal combustion engines is reported. Coherent anti-Stokes Raman spectroscopy (CARS) is used to probe the fuel-air mixture in the cylinder of a Richardo E6 variable compression ratio research engine. The laser system comprises a passively Q- switched single-longitudinal-mode frequency-doubled Nd:YAG laser and a broadband dye laser, both with a pulse length of 15 ns. A crankshaft encoder and electronic delay are used to fire the lasers at specified times during the engine cycle, and CARS spectra are acquired using a 0.75 m spectrometer and a 1024 optical multichannel analyzer. Because of the uncertainties associated with collisional narrowing in the theoretical modeling of high-pressure CARS spectra, temperatures are determined by comparing the engine spectra with a library of experimental CARS spectra from a calibrated high-pressure, high- temperature cell. This purely experimental technique is shown to be superior to two theoretical models under the considered conditions, giving temperatures during the compression stroke of the engine with standard deviations of typically 10 K and a possible systematic error of 15 K. Together with pressure records, this information is used as input data for chemical kinetic modeling of the combustion process.

Exhaust gas heat recovery through secondary expansion cylinder and water injection in an internal combustion engine

Directory of Open Access Journals (Sweden)

Nassiri Toosi Ali

2017-01-01

Full Text Available To enhance thermal efficiency and increase performance of an internal combustion engine, a novel concept of coupling a conventional engine with a secondary 4-stroke cylinder and direct water injection process is proposed. The burned gases after working in a traditional 4-stroke combustion cylinder are transferred to a secondary cylinder and expanded even more. After re-compression of the exhaust gases, pre-heated water is injected at top dead center. The evaporation of injected water not only recovers heat from exhaust gases, but also increases the mass of working gas inside the cylinder, therefore improves the overall thermal efficiency. A 0-D/1-D model is used to numerically simulate the idea. The simulations outputs showed that the bottoming cycle will be more efficient at higher engines speeds, specifically in a supercharged/turbocharged engine, which have higher exhaust gas pressure that can reproduce more positive work. In the modeled supercharged engine, results showed that brake thermal efficiency can be improved by about 17%, and brake power by about 17.4%.

Exhaust Composition in a Small Internal Combustion Engine Using FTIR Spectroscopy

Science.gov (United States)

2015-06-18

consumption of intake charge by mass xv CAD crank angle degrees CI compression ignition COTS commercial o↵ the shelf CoV coecient of variance C... ignition (SI) and compression ignition (CI). A spark ignition engine ignites the fuel-air mixture via an electric arc across a spark plug located in...two-stroke engines that operate at very high speeds. The heat of combustion is transferred to a fine wire that remains hot enough to auto - ignite the

Miniaturization limitations of rotary internal combustion engines

International Nuclear Information System (INIS)

Wang, Wei; Zuo, Zhengxing; Liu, Jinxiang

2016-01-01

Highlights: • Developed a phenomenological model for rotary internal combustion engines. • Presented scaling laws for the performance of micro rotary engines. • Adiabatic walls can improve the cycle efficiency but result in higher charge leakage. • A lower compression ratio can increase the efficiency due to lower mass losses. • Presented possible minimum engine size of rotary internal combustion engines. - Abstract: With the rapid development of micro electro-mechanical devices, the demands for micro power generation systems have significantly increased in recent years. Traditional chemical batteries have energy densities much lower than hydrocarbon fuels, which makes internal-combustion-engine an attractive technological alternative to batteries. Micro rotary internal combustion engine has drawn great attractions due to its planar design, which is well-suited for fabrication in MEMS. In this paper, a phenomenological model considering heat transfer and mass leakage has been developed to investigate effects of engine speed, compression ratio, blow-by and heat transfer on the performance of micro rotary engine, which provide the guidelines for preliminary design of rotary engine. The lower possible miniaturization limits of rotary combustion engines are proposed.

The effects of key parameters on the transition from SI combustion to HCCI combustion in a two-stroke free piston linear engine

International Nuclear Information System (INIS)

Hung, Nguyen Ba; Lim, Ocktaeck; Iida, Norimasa

2015-01-01

Highlights: • A free piston engine is modeled and simulated by three mathematical models. • The models include dynamic model, linear alternator model and thermodynamic model. • The SI-HCCI transition is successful if the key parameters are adjusted suitably. • Spring stiffness has a strong influence on reducing peak temperature in HCCI mode. • Adjusting spark timing helps the SI-HCCI transition to be more convenient. - Abstract: An investigation was conducted to examine the effects of key parameters such as intake temperature, equivalence ratio, engine load, intake pressure, spark timing and spring stiffness on the transition from SI combustion to HCCI combustion in a two-stroke free piston linear engine. Operation of the free piston engine was simulated based on the combination of three mathematical models including a dynamic model, a linear alternator model and a thermodynamic model. These mathematical models were combined and solved by a program written in Fortran. To validate the mathematical models, the simulation results were compared with experimental data in the SI mode. For the transition from SI combustion to HCCI combustion, the simulation results show that if the equivalence ratio is decreased, the intake temperature and engine load should be increased to get a successful SI-HCCI transition. However, the simulation results also show that the in-cylinder pressure is decreased, while the peak in-cylinder temperature in HCCI mode is increased significantly if the intake temperature is increased so much. Beside the successful SI-HCCI transition, the increase of intake pressure from P in = 1.1 bar to P in = 1.6 bar is one of solutions to reduce peak in-cylinder temperature in HCCI mode. However, the simulation results also indicate that if the intake pressure is increased so much (P in = 1.6 bar), the engine knocking problem is occurred. Adjusting spring stiffness from k = 2.9 N/mm to k = 14.7 N/mm is also considered one of useful solutions for

3rd International Workshop on Turbulent Spray Combustion

CERN Document Server

Gutheil, Eva

2014-01-01

This book reflects the results of the 2nd and 3rd International Workshops on Turbulent Spray Combustion. The focus is on progress in experiments and numerical simulations for two-phase flows, with emphasis on spray combustion. Knowledge of the dominant phenomena and their interactions allows development of predictive models and their use in combustor and gas turbine design. Experts and young researchers present the state-of-the-art results, report on the latest developments and exchange ideas in the areas of experiments, modelling and simulation of reactive multiphase flows. The first chapter reflects on flame structure, auto-ignition and atomization with reference to well-characterized burners, to be implemented by modellers with relative ease. The second chapter presents an overview of first simulation results on target test cases, developed at the occasion of the 1st International Workshop on Turbulent Spray Combustion. In the third chapter, evaporation rate modelling aspects are covered, while the fourth ...

Producer for vegetal combustibles for internal-combustion motors

Energy Technology Data Exchange (ETDEWEB)

1943-12-28

A producer is described for internal-combustion motors fed with wood or agricultural byproducts characterized by the fact that its full operation is independent of the degree of wetness of the material used.

Two Stroke Diesel Engines for Large Ship Propulsion

DEFF Research Database (Denmark)

Haider, Sajjad

In low speed large two-stroke marine diesel engines, uniflow scavenging is used to remove the exhaust gases from the cylinder and fill the cylinder with fresh air charge for the next cycle. The swirl enhances the mixing of fuel with air and improves combustion efficiency. The thesis focuses...... downstream. As the port closes, the mixing of smoke particles in the core with surrounding regions is enhanced. The hollow conical smoke pattern disappears and resembles to a jet. Laser Doppler Anemometry measurements are conducted in the swirl generator and at the entrance to the test cylinder. The results...

Internal combustion engine and method for control

Science.gov (United States)

Brennan, Daniel G

2013-05-21

In one exemplary embodiment of the invention an internal combustion engine includes a piston disposed in a cylinder, a valve configured to control flow of air into the cylinder and an actuator coupled to the valve to control a position of the valve. The internal combustion engine also includes a controller coupled to the actuator, wherein the controller is configured to close the valve when an uncontrolled condition for the internal engine is determined.

Injector tip for an internal combustion engine

Science.gov (United States)

Shyu, Tsu Pin; Ye, Wen

2003-05-20

This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

Modeling of Combined Heat and Power Plant Based on a Multi-Stage Gasifier and Internal Combustion Engines of Various Power Outputs

Science.gov (United States)

Khudyakova, G. I.; Kozlov, A. N.; Svishchev, D. A.

2017-11-01

The paper is concerned with an integrated system of internal combustion engine and mini combined heat and power plant (ICE-CHP). The system is based on multi-stage wood biomass gasification. The use of producer gas in the system affects negatively the internal combustion engine performance and, therefore, reduces the efficiency of the ICE-CHP plant. A mathematical model of an internal combustion engine running on low-calorie producer gas was developed using an overview of Russian and foreign manufacturers of reciprocating units, that was made in the research. A thermal calculation was done for four-stroke gas engines of different rated power outputs (30, 100 and 250 kW), running on producer gas (CO2 - 10.2, CO - 45.8, N2 - 38.8%). Thermal calculation demonstrates that the engine exhaust gas temperature reaches 500 - 600°C at the rated power level and with the lower engine power, the temperature gets higher. For example, for an internal combustion engine power of 1000 kW the temperature of exhaust gases equals 400°C. A comparison of the efficiency of engine operation on natural gas and producer gas shows that with the use of producer gas the power output declines from 300 to 250 kWe. The reduction in the effective efficiency in this case makes up 2%. The measures are proposed to upgrade the internal combustion engine to enable it to run on low-calorie producer gas.

Estimation of the in-cylinder air/fuel ratio of an internal combustion engine by the use of pressure sensors

Energy Technology Data Exchange (ETDEWEB)

Tunestaal, Per

2000-03-01

This thesis investigates the use of cylinder pressure measurements for estimation of the in-cylinder air/fuel ratio in a spark ignited internal combustion engine. An estimation model which uses the net heat release profile for estimating the cylinder air/fuel ratio of a spark ignition engine is developed. The net heat release profile is computed from the cylinder pressure trace and quantifies the conversion of chemical energy of the reactants in the charge into thermal energy. The net heat release profile does not take heat- or mass transfer into account. Cycle-averaged air/fuel ratio estimates over a range of engine speeds and loads show an RMS error of 4.1% compared to measurements in the exhaust. A thermochemical model of the combustion process in an internal combustion engine is developed. It uses a simple chemical combustion reaction, polynominal fits of internal energy as function of temperature, and the first law of thermodynamics to derive a relationship between measured cylinder pressure and the progress of the combustion process. Simplifying assumptions are made to arrive at an equation which relates the net heat release to the cylinder pressure. Two methods for estimating the sensor offset of a cylinder pressure transducer are developed. Both methods fit the pressure data during the pre-combustion phase of the compression stroke to a polytropic curve. The first method assumes a known polytropic exponent, and the other estimates the polytropic exponent. The first method results in a linear least-squares problem, and the second method results in a nonlinear least-squares problem. The nonlinear least-squares problem is solved by separating out the nonlinear dependence and solving the single-variable minimization problem. For this, a finite difference Newton method is derived. Using this method, the cost of solving the nonlinear least-squares problem is only slightly higher than solving the linear least-squares problem. Both methods show good statistical

ANALYSIS OF INTERNAL COMBUSTION ENGINE WITH A NEW CONCEPT OF POROUS MEDIUM COMBUSTION FOR THE FUTURE CLEAN ENGINE

Directory of Open Access Journals (Sweden)

Ashok A Dhale

2010-01-01

Full Text Available At present, the emissions of internal combustion engine can only be improved by catalytic treatments of the exhaust gases. Such treatments, however, result in high costs and relatively low conversion efficiency. This suggests that a new combustion technique should be developed to yield improved primary combustion processes inside the engine with drastically reduced exhaust gas emissions. To fulfill all requirements, Dr. Franz Drust has proposed a new combustion concept to perform homogenous combustion in internal combustion engines. This concept used the porous medium combustion technique and is called "PM-engine". It is shown that the PM combustion technique can be applied to internal combustion engines. Theoretical considerations are presented for internal combustion engines, indicating that an overall improvement in thermal efficiency can be achieved for the PM-engine. This is explained and general performance of the new PM-engines is demonstrated for a single cylinder, water cooled, direct injection diesel engine. Verification of experiments at primary stage is described that were carried out as a part of the present study.

Ignition system for an internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Imhof, G

1977-05-12

The invention pertains to ignition systems for internal combustion engines; in particular, these are used in the engines of modern small motorcycles, where power is supplied by means of a so-called flywheel magneto, so that there is no need for an additional battery. The invention will prevent back-kicking. This is achieved by the following means: in the right direction of rotation of the internal combustion engine, due to an axial magnetic unsymmetry of the rotor, a voltage component that can switch the electronic switch will occur only in one of the two parts of the control winding at the point of ignition. In the wrong direction of rotation, on the other hand, this voltage component will only occur in the other part of the control winding and will act in direction on a diode connected in parallel to this part of the winding.

A new hybrid pneumatic combustion engine to improve fuel consumption of wind–Diesel power system for non-interconnected areas

International Nuclear Information System (INIS)

Basbous, Tammam; Younes, Rafic; Ilinca, Adrian; Perron, Jean

2012-01-01

Highlights: ► We model thermodynamic ideal cycle of a new hybrid pneumaticcombustion engine. ► We optimize commands of all modes and calculate maps of fuel and air consumption. ► We evaluate fuel economy for Wind–Diesel system function of tank volume and wind penetration. ► We find up to 10% of fuel economy i.e. 80 t/year with 100% wind penetration. ► Fuel economy increases with wind penetration and with volume but has asymptotic value. -- Abstract: This paper presents an evaluation of an optimized Hybrid Pneumatic-Combustion Engine (HPCE) concept that permits reducing fuel consumption for electricity production in non-interconnected remote areas, originally equipped with hybrid Wind–Diesel System (WDS). Up to now, most of the studies on the pneumatic hybridization of Internal Combustion Engines (ICE) have dealt with two-stroke pure pneumatic mode. The few studies that have dealt with hybrid pneumatic-combustion four-stroke mode require adding a supplementary valve to charge compressed air in the combustion chamber. This modification means that a new cylinder head should be fabricated. Moreover, those studies focus on spark ignition engines and are not yet validated for Diesel engines. Present HPCE is capable of making a Diesel engine operate under two-stroke pneumatic motor mode, two-stroke pneumatic pump mode and four-stroke hybrid mode, without needing an additional valve in the combustion chamber. This fact constitutes this study’s strength and innovation. The evaluation of the concept is based on ideal thermodynamic cycle modeling. The optimized valve actuation timings for all modes lead to generic maps that are independent of the engine size. The fuel economy is calculated for a known site during a whole year, function of the air storage volume and the wind power penetration rate.

Comparison of different chemical kinetic mechanisms of methane combustion in an internal combustion engine configuration

OpenAIRE

Ennetta Ridha; Hamdi Mohamed; Said Rachid

2008-01-01

Three chemical kinetic mechanisms of methane combustion were tested and compared using the internal combustion engine model of Chemkin 4.02 [1]: one-step global reaction mechanism, four-step mechanism, and the standard detailed scheme GRIMECH 3.0. This study shows good concordances, especially between the four-step and the detailed mechanisms in the prediction of temperature and main species profiles. But reduced schemes were incapables to predict pollutant emissions in an internal combustion...

Free Energy and Internal Combustion Engine Cycles

OpenAIRE

Harris, William D.

2012-01-01

The performance of one type (Carnot) of Internal Combustion Engine (ICE) cycle is analyzed within the framework of thermodynamic free energies. ICE performance is different from that of an External Combustion Engine (ECE) which is dictated by Carnot's rule.

Prototype testing and analysis of a novel internal combustion linear generator integrated power system

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhaoping; Chang, Siqin [School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China)

2010-04-15

A novel four-stroke free-piston engine equipped with a linear electric generator (namely internal combustion linear generator integrated power system) is proposed in this paper to achieve efficient energy conversion from fuel to electricity. Unique features of the novel power system are presented and their effects on the continuous running are discussed, along with potential advantages and disadvantages compared to conventional engines. A single cylinder, gasoline and spark ignition prototype is fabricated with reference to the geometric and control parameters of an existing conventional four-stroke engine. Stable running of the prototype is realized, and a 2.2 kW average output power with the generating efficiency of 32% has been obtained up to now. The feasibility and performance of the proposed design are verified. Detailed testing results from the continuous running prototype are analyzed in this paper for giving insight into the performance and dynamic behaviors of the novel power system. (author)

Integrated Analysis of the Scavenging Process in Marine Two-Stroke Diesel Engines

DEFF Research Database (Denmark)

Andersen, Fredrik Herland

Large commercial ships such as container vessels and bulk carriers are propelledby low-speed, uniow scavenged two-stroke diesel engines. An integralin-cylinder process in this type of engine is the scavenging process, where the burned gases from the combustion process are evacuated through...... receiver fora two-stroke diesel engine. Time resolved boundary conditions corresponding to measurements obtained from an operating engine as well as realistic initial conditions are used in the simulations. The CFD model provides a detailed description of the in-cylinder ow from exhaust valve opening (EVO...... in the scavenge and exhaust receivers increase while the scavenge port exposure time, tscav, decrease. Further the scavenging pressure is varied while the engine speed is kept constant. From the perspective of the scavenging process this will resemble a load sweep following a generator curve. The scavenge port...

Jet plume injection and combustion system for internal combustion engines

Science.gov (United States)

Oppenheim, Antoni K.; Maxson, James A.; Hensinger, David M.

1993-01-01

An improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion pressure in the cylinder, as well as shortening the time period to attain such a maximum pressure.

An Investigation of the Composition of the Flow in and out of a Two-Stroke Diesel Engine and Air Consumption Ratio

Directory of Open Access Journals (Sweden)

Mirko Grljušić

2017-06-01

Full Text Available The aim of this research was to investigate the mass, substance and energy flow through two-stroke low speed Diesel engines. For this reason, a zero-dimensional model of the combustion in the engine was developed with a calculated amount and composition of exhaust gases. Due to the large amount of oxygen in the exhaust gases, a ratio of real air consumption and stoichiometric amount of air required for combustion of injected fuel was set. The calculated ratio showed that the engine consumed four times more air than needed for combustion in AFRstoich. In this work, this was called the Air Consumption Factor or Ratio, and has not previously been mentioned in scientific literature. The air consumption ratio is defined as a factor of dry or humid air. To be more comprehensive, a modified diagram of the composition of the flow in and out of a two-stroke fuel injection engine and the cylinder was made.

Personal exposure to benzene from fuel emissions among commercial fishers: comparison of two-stroke, four-stroke and diesel engines.

Science.gov (United States)

Kirrane, Ellen; Loomis, Dana; Egeghy, Peter; Nylander-French, Leena

2007-03-01

Commercial fishers are exposed to unburned hydrocarbon vapors and combustion products present in the emissions from their boat engines. The objective of this study was to measure personal exposure to benzene as a marker of fuel exposure, and to predict exposure levels across categories of carbureted two-stroke, four-stroke and diesel engines. A self-monitoring approach, employing passive monitors, was used to obtain measurements of personal exposure to benzene over time. Mixed-effect linear regression models were used to predict exposure levels, identify significant effects and determine restricted maximum likelihood estimates for within- and between-person variance components. Significant fixed effects for engine type and refueling a car or truck were identified. After controlling for refueling, predicted benzene exposure levels to fishers on boats equipped with two-stroke, four-stroke and diesel engines were 58.4, 38.9 and 15.7 microg/m3, respectively. The logged within-person variance component was 1.43, larger than the between-person variance component of 1.13, indicating that the total variation may be attributable to monitor placement, environmental conditions and other factors that change over time as well as differences between individual work practices. The health consequences of exposure to marine engine emissions are not known. The predicted levels are well below those at which health effects have been attributed, however.

Preliminary assessment of combustion modes for internal combustion wave rotors

Science.gov (United States)

Nalim, M. Razi

1995-01-01

Combustion within the channels of a wave rotor is examined as a means of obtaining pressure gain during heat addition in a gas turbine engine. Several modes of combustion are considered and the factors that determine the applicability of three modes are evaluated in detail; premixed autoignition/detonation, premixed deflagration, and non-premixed compression ignition. The last two will require strong turbulence for completion of combustion in a reasonable time in the wave rotor. The compression/autoignition modes will require inlet temperatures in excess of 1500 R for reliable ignition with most hydrocarbon fuels; otherwise, a supplementary ignition method must be provided. Examples of combustion mode selection are presented for two core engine applications that had been previously designed with equivalent 4-port wave rotor topping cycles using external combustion.

Modeling internal ballistics of gas combustion guns.

Science.gov (United States)

Schorge, Volker; Grossjohann, Rico; Schönekess, Holger C; Herbst, Jörg; Bockholdt, Britta; Ekkernkamp, Axel; Frank, Matthias

2016-05-01

Potato guns are popular homemade guns which work on the principle of gas combustion. They are usually constructed for recreational rather than criminal purposes. Yet some serious injuries and fatalities due to these guns are reported. As information on the internal ballistics of homemade gas combustion-powered guns is scarce, it is the aim of this work to provide an experimental model of the internal ballistics of these devices and to investigate their basic physical parameters. A gas combustion gun was constructed with a steel tube as the main component. Gas/air mixtures of acetylene, hydrogen, and ethylene were used as propellants for discharging a 46-mm caliber test projectile. Gas pressure in the combustion chamber was captured with a piezoelectric pressure sensor. Projectile velocity was measured with a ballistic speed measurement system. The maximum gas pressure, the maximum rate of pressure rise, the time parameters of the pressure curve, and the velocity and path of the projectile through the barrel as a function of time were determined according to the pressure-time curve. The maximum gas pressure was measured to be between 1.4 bar (ethylene) and 4.5 bar (acetylene). The highest maximum rate of pressure rise was determined for hydrogen at (dp/dt)max = 607 bar/s. The muzzle energy was calculated to be between 67 J (ethylene) and 204 J (acetylene). To conclude, this work provides basic information on the internal ballistics of homemade gas combustion guns. The risk of injury to the operator or bystanders is high, because accidental explosions of the gun due to the high-pressure rise during combustion of the gas/air mixture may occur.

Variable compression ratio device for internal combustion engine

Science.gov (United States)

Maloney, Ronald P.; Faletti, James J.

2004-03-23

An internal combustion engine, particularly suitable for use in a work machine, is provided with a combustion cylinder, a cylinder head at an end of the combustion cylinder and a primary piston reciprocally disposed within the combustion cylinder. The cylinder head includes a secondary cylinder and a secondary piston reciprocally disposed within the secondary cylinder. An actuator is coupled with the secondary piston for controlling the position of the secondary piston dependent upon the position of the primary piston. A communication port establishes fluid flow communication between the combustion cylinder and the secondary cylinder.

Combustion, detonation, shock waves. Proceedings of the Zel'dovich memorial - International conference on combustion. Volume 1

International Nuclear Information System (INIS)

Merzhanov, A.G.; Frolov, S.M.

1995-01-01

This book contains lectures by the experts in various fields of modern research in combustion, detonation and shock waves, presented at the Zel'dovich memorial - International conference on combustion dedicated to the 80-th birthday of academician Ya.B. Zel'dovich. There are eight chapters discussing the state-of-the-art in combustion kinetics, ignition and steady-state flame propagation, diffusion and heterogeneous combustion, turbulent combustion, unsteady combustion, detonation, combustion and detonation analogies, intense shock waves and extreme states of matter [ru

49 CFR 173.220 - Internal combustion engines, self-propelled vehicles, mechanical equipment containing internal...

Science.gov (United States)

2010-10-01

... and vehicles with certain electronic equipment when transported by aircraft or vessel. When an... vehicles, mechanical equipment containing internal combustion engines, and battery powered vehicles or... Than Class 1 and Class 7 § 173.220 Internal combustion engines, self-propelled vehicles, mechanical...

Engine combustion control at low loads via fuel reactivity stratification

Science.gov (United States)

Reitz, Rolf Deneys; Hanson, Reed M; Splitter, Derek A; Kokjohn, Sage L

2014-10-07

A compression ignition (diesel) engine uses two or more fuel charges during a combustion cycle, with the fuel charges having two or more reactivities (e.g., different cetane numbers), in order to control the timing and duration of combustion. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot). At low load and no load (idling) conditions, the aforementioned results are attained by restricting airflow to the combustion chamber during the intake stroke (as by throttling the incoming air at or prior to the combustion chamber's intake port) so that the cylinder air pressure is below ambient pressure at the start of the compression stroke.

Engine combustion control at low loads via fuel reactivity stratification

Energy Technology Data Exchange (ETDEWEB)

Reitz, Rolf Deneys; Hanson, Reed M.; Splitter, Derek A.; Kokjohn, Sage

2017-12-26

A compression ignition (diesel) engine uses two or more fuel charges during a combustion cycle, with the fuel charges having two or more reactivities (e.g., different cetane numbers), in order to control the timing and duration of combustion. By appropriately choosing the reactivities of the charges, their relative amounts, and their timing, combustion can be tailored to achieve optimal power output (and thus fuel efficiency), at controlled temperatures (and thus controlled NOx), and with controlled equivalence ratios (and thus controlled soot). At low load and no load (idling) conditions, the aforementioned results are attained by restricting airflow to the combustion chamber during the intake stroke (as by throttling the incoming air at or prior to the combustion chamber's intake port) so that the cylinder air pressure is below ambient pressure at the start of the compression stroke.

Method and device for diagnosing and controlling combustion instabilities in internal combustion engines operating in or transitioning to homogeneous charge combustion ignition mode

Science.gov (United States)

Wagner, Robert M [Knoxville, TN; Daw, Charles S [Knoxville, TN; Green, Johney B [Knoxville, TN; Edwards, Kevin D [Knoxville, TN

2008-10-07

This invention is a method of achieving stable, optimal mixtures of HCCI and SI in practical gasoline internal combustion engines comprising the steps of: characterizing the combustion process based on combustion process measurements, determining the ratio of conventional and HCCI combustion, determining the trajectory (sequence) of states for consecutive combustion processes, and determining subsequent combustion process modifications using said information to steer the engine combustion toward desired behavior.

Numerical Simulation of Condensation of Sulfuric Acid and Water in a Large Two-stroke Marine Diesel Engine

DEFF Research Database (Denmark)

Walther, Jens Honore; Karvounis, Nikolas; Pang, Kar Mun

2016-01-01

We present results from computational fluid dynamics simulations of the condensation of sulfuric acid (H2SO4) and water (H2O) in a large two-stroke marine diesel engine. The model uses a reduced n-heptane skeletal chemical mechanism coupled with a sulfur subsetto simulate the combustion process...

Experimental studies of thermal preparation of internal combustion engine

Science.gov (United States)

Karnaukhov, N. N.; Merdanov, Sh M.; V, Konev V.; Borodin, D. M.

2018-05-01

In conditions of autonomous functioning of road construction machines, it becomes necessary to use its internal sources. This can be done by using a heat recovery system of an internal combustion engine (ICE). For this purpose, it is proposed to use heat accumulators that accumulate heat of the internal combustion engine during the operation of the machine. Experimental studies have been carried out to evaluate the efficiency of using the proposed pre-start thermal preparation system, which combines a regular system based on liquid diesel fuel heaters and an ICE heat recovery system. As a result, the stages of operation of the preheating thermal preparation system, mathematical models and the dependence of the temperature change of the antifreeze at the exit from the internal combustion engine on the warm-up time are determined.

46 CFR 32.35-5 - Installation of internal combustion engines-TB/ALL.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Installation of internal combustion engines-TB/ALL. 32... EQUIPMENT, MACHINERY, AND HULL REQUIREMENTS Main and Auxiliary Machinery § 32.35-5 Installation of internal combustion engines—TB/ALL. Each internal combustion engine located on the weather deck shall be provided with...

78 FR 54606 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2013-09-05

... Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines AGENCY... hazardous air pollutants for stationary reciprocating internal combustion engines and the standards of performance for stationary internal combustion engines. Subsequently, the EPA received three petitions for...

Computation and Analysis of EGR Mixing in Internal Combustion Engine Manifolds

OpenAIRE

Sakowitz, Alexander

2013-01-01

This thesis deals with turbulent mixing processes occurring in internal combustion engines, when applying exhaust gas recirculation (EGR). EGR is a very efficient way to reduce emissions of nitrogen oxides (NOx) in internal combustion engines. Exhaust gases are recirculated and mixed with the fresh intake air, reducing the oxygen con- centration of the combustion gas and thus the peak combustion temperatures. This temperature decrease results in a reduction of NOx emissions. When applying EGR...

Internal combustion engine for natural gas compressor operation

Energy Technology Data Exchange (ETDEWEB)

Hagen, Christopher; Babbitt, Guy

2016-12-27

This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a method is featured which includes placing a first cylinder of an internal combustion engine in a compressor mode, and compressing a gas within the first cylinder, using the cylinder as a reciprocating compressor. In some embodiments a compression check valve system is used to regulate pressure and flow within cylinders of the engine during a compression process.

Process gas generator feeding internal combustion piston engines

Energy Technology Data Exchange (ETDEWEB)

Iwantscheff, G; Kostka, H; Henkel, H J

1978-10-26

The invention relates to a process gas generator feeding gaseous fuel to internal combustion piston engines. The cylinder linings of the internal combustion engine are enclosed by the catalytic reaction chamber of the process gas generator which contains perforated sintered nozzle bricks as carriers of the catalysts needed for the conversion. The reaction chamber is surrounded by the exhaust gas chamber around which a tube coil is ound which feeds the fuel charge to the reaction chamber after evaporation and mixing with exhaust gas and air. The fuel which may be used for this purpose, e.g., is low-octane gasoline or diesel fuel. In the reaction chamber the fuel is catalytically converted at temperatures above 200/sup 0/C, e.g., into low-molecular paraffins, carbon monoxide and hydrogen. Operation of the internal combustion engine with a process gas generator greatly reduces the pollutant content of the exhaust gases.

8th International symposium on transport phenomena in combustion

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-12-31

The 8th International Symposium on Transport Phenomena in Combustion will be held in San Francisco, California, U.S.A., July 16-20, 1995, under the auspices of the Pacific Center of Thermal-Fluids Engineering. The purpose of the Symposium is to provide a forum for researchers and practitioners from around the world to present new developments and discuss the state of the art and future directions and priorities in the areas of transport phenomena in combustion. The Symposium is the eighth in a series; previous venues were Honolulu 1985, Tokyo 1987, Taipei 1988, Sydney 1991, Beijing 1992, Seoul 1993 and Acapulco 1994, with emphasis on various aspects of transport phenomena. The current Symposium theme is combustion. The Symposium has assembled a balanced program with topics ranging from fundamental research to contemporary applications of combustion theory. Invited keynote lecturers will provide extensive reviews of topics of great interest in combustion. Colloquia will stress recent advances and innovations in fire spread and suppression, and in low NO{sub x} burners, furnaces, boilers, internal combustion engines, and other practical combustion systems. Finally, numerous papers will contribute to the fundamental understanding of complex processes in combustion. This document contains abstracts of papers to be presented at the Symposium.

International evaluation of the programme on engine-related combustion

Energy Technology Data Exchange (ETDEWEB)

Arcoumanis, D [Imperial College, London (United Kingdom); Greenhalgh, D [Cranfield Univ. (United Kingdom); Magnusson, B F [Norwegian Univ. of Science and Technology, Trondheim (Norway); Peters, N [Institut fuer Technische Mechanik, RWTH Aachen (Germany)

1996-11-01

The 12 projects in the engine related combustion programme cover the entire range from fundamental and theoretical aspects of combustion to more applied subjects such as engine control. The common denominator in the programme clearly is the internal combustion engine, both the reciprocating as well as the gas turbine engine. Such a large coverage by a relatively small number of projects necessarily leads to an isolation of some of the projects in terms of their subject as well as the methodology that is used. On the other hand, all the research areas of interest in combustion technology are represented by at least one of the projects. These are: mathematical and numerical methods in combustion; modelling of turbulent combustion; laser diagnostics of flows with combustion; studies of engine performance and their control; semi-empirical model development for practical applications. As a conclusion, the evaluation committee believes that the programme is well balanced between fundamental and applied projects. It covers the entire range of modern methodologies that are used on the international level and thereby contributes to the application and further development of these research tools in Sweden

Flow effects due to valve and piston motion in an internal combustion engine exhaust port

International Nuclear Information System (INIS)

Semlitsch, Bernhard; Wang, Yue; Mihăescu, Mihai

2015-01-01

Highlights: • Flow regime identification depending on the valve lift during the exhaust stroke. • Analysis of the valve motion effect onto the flow development in the exhaust port. • Physical interpretation of commonly used discharge and flow coefficient formulations. • Illustration of flow effects in junction regions with pulsatile flow. - Abstract: Performance optimization regarding e.g. exhaust valve strategies in an internal combustion engine is often performed based on one-dimensional simulation investigation. Commonly, a discharge coefficient is used to describe the flow behavior in complex geometries, such as the exhaust port. This discharge coefficient for an exhaust port is obtained by laboratory experiments at fixed valve lifts, room temperatures, and low total pressure drops. The present study investigates the consequences of the valve and piston motion onto the energy losses and the discharge coefficient. Therefore, Large Eddy Simulations are performed in a realistic internal combustion geometry using three different modeling strategies, i.e. fixed valve lift and fixed piston, moving piston and fixed valve lift, and moving piston and moving valve, to estimate the energy losses. The differences in the flow field development with the different modeling approaches is delineated and the dynamic effects onto the primary quantities, e.g. discharge coefficient, are quantified. Considering the motion of piston and valves leads to negative total pressure losses during the exhaust cycle, which cannot be observed at fixed valve lifts. Additionally, the induced flow structures develop differently when valve motion is taken into consideration, which leads to a significant disparity of mass flow rates evolving through the two individual valve ports. However, accounting for piston motion and limited valve motion, leads to a minor discharge coefficient alteration of about one to two percent

Cost effective simulation-based multiobjective optimization in the performance of an internal combustion engine

Science.gov (United States)

Aittokoski, Timo; Miettinen, Kaisa

2008-07-01

Solving real-life engineering problems can be difficult because they often have multiple conflicting objectives, the objective functions involved are highly nonlinear and they contain multiple local minima. Furthermore, function values are often produced via a time-consuming simulation process. These facts suggest the need for an automated optimization tool that is efficient (in terms of number of objective function evaluations) and capable of solving global and multiobjective optimization problems. In this article, the requirements on a general simulation-based optimization system are discussed and such a system is applied to optimize the performance of a two-stroke combustion engine. In the example of a simulation-based optimization problem, the dimensions and shape of the exhaust pipe of a two-stroke engine are altered, and values of three conflicting objective functions are optimized. These values are derived from power output characteristics of the engine. The optimization approach involves interactive multiobjective optimization and provides a convenient tool to balance between conflicting objectives and to find good solutions.

Modeling the internal combustion engine

Science.gov (United States)

Zeleznik, F. J.; Mcbride, B. J.

1985-01-01

A flexible and computationally economical model of the internal combustion engine was developed for use on large digital computer systems. It is based on a system of ordinary differential equations for cylinder-averaged properties. The computer program is capable of multicycle calculations, with some parameters varying from cycle to cycle, and has restart capabilities. It can accommodate a broad spectrum of reactants, permits changes in physical properties, and offers a wide selection of alternative modeling functions without any reprogramming. It readily adapts to the amount of information available in a particular case because the model is in fact a hierarchy of five models. The models range from a simple model requiring only thermodynamic properties to a complex model demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. Among its many features the model includes heat transfer, valve timing, supercharging, motoring, finite burning rates, cycle-to-cycle variations in air-fuel ratio, humid air, residual and recirculated exhaust gas, and full combustion kinetics.

Plasma igniter for internal combustion engine

Science.gov (United States)

Fitzgerald, D. J.; Breshears, R. R. (Inventor)

1978-01-01

An igniter for the air/fuel mixture used in the cylinders of an internal combustion engine is described. A conventional spark is used to initiate the discharge of a large amount of energy stored in a capacitor. A high current discharge of the energy in the capacitor switched on by a spark discharge produces a plasma and a magnetic field. The resultant combined electromagnetic current and magnetic field force accelerates the plasma deep into the combustion chamber thereby providing an improved ignition of the air/fuel mixture in the chamber.

76 FR 12923 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2011-03-09

... National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines... pollutants for existing stationary spark ignition reciprocating internal combustion engines. The final rule... reciprocating internal combustion generation, engine. transmission, or distribution. 622110 Medical and surgical...

75 FR 51569 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2010-08-20

... Air Pollutants for Reciprocating Internal Combustion Engines; Final Rule #0;#0;Federal Register / Vol... for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines AGENCY: Environmental... hazardous air pollutants for existing stationary spark ignition reciprocating internal combustion engines...

77 FR 60341 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2012-10-03

... National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines AGENCY: Environmental Protection... Pollutants for Stationary Reciprocating Internal Combustion Engines to solicit comment on specific issues...

77 FR 37361 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2012-06-21

... National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines AGENCY: Environmental Protection... Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source Performance...

Combustion Heat Release Rate Comparison of Algae Hydroprocessed Renewable Diesel to F-76 in a Two-Stroke Diesel Engine

Science.gov (United States)

2013-06-01

was recorded. Figure 14 shows the gauge on the rocker arm during calibration . Figure 14. Mechanical Injector Rocker Arm Strain Gauge. D. DATA...RELEASE RATE COMPARISON OF ALGAE HYDROPROCESSED RENEWABLE DIESEL TO F-76 IN A TWO-STROKE DIESEL ENGINE by John H. Petersen June 2013 Thesis...RELEASE RATE COMPARISON OF ALGAE HYDROPROCESSED RENEWABLE DIESEL TO F-76 IN A TWO-STROKE DIESEL ENGINE 5. FUNDING NUMBERS 6. AUTHOR(S) John H

77 FR 33811 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2012-06-07

... 63 National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines; Proposed Rule #0;#0... Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source...

Free piston variable-stroke linear-alternator generator

Science.gov (United States)

Haaland, Carsten M.

1998-01-01

A free-piston variable stroke linear-alternator AC power generator for a combustion engine. An alternator mechanism and oscillator system generates AC current. The oscillation system includes two oscillation devices each having a combustion cylinder and a flying turnbuckle. The flying turnbuckle moves in accordance with the oscillation device. The alternator system is a linear alternator coupled between the two oscillation devices by a slotted connecting rod.

Flow effects due to pulsation in an internal combustion engine exhaust port

International Nuclear Information System (INIS)

Semlitsch, Bernhard; Wang, Yue; Mihăescu, Mihai

2014-01-01

Highlights: • Using POD analysis to identify large coherent flow structures in a complex geometry. • Flow field alters significant for constant and pulsating boundary conditions. • The discharge coefficient of the exhaust port decreases 2% with flow pulsation. • Pulsation causes a pumping mechanism due to a phase shift of pressure and momentum. - Abstract: In an internal combustion engine, the residual energy remaining after combustion in the exhaust gasses can be partially recovered by a downstream arranged device. The exhaust port represents the passage guiding the exhaust gasses from the combustion chamber to the energy recovering device, e.g. a turbocharger. Thus, energy losses in the course of transmission shall be reduced as much as possible. However, in one-dimensional engine models used for engine design, the exhaust port is reduced to its discharge coefficient, which is commonly measured under constant inflow conditions neglecting engine-like flow pulsation. In this present study, the influence of different boundary conditions on the energy losses and flow development during the exhaust stroke are analyzed numerically regarding two cases, i.e. using simple constant and pulsating boundary conditions. The compressible flow in an exhaust port geometry of a truck engine is investigated using three-dimensional Large Eddy Simulations (LES). The results contrast the importance of applying engine-like boundary conditions in order to estimate accurately the flow induced losses and the discharge coefficient of the exhaust port. The instantaneous flow field alters significantly when pulsating boundary conditions are applied. Thus, the induced losses by the unsteady flow motion and the secondary flow motion are increased with inflow pulsations. The discharge coefficient decreased about 2% with flow pulsation. A modal flow decomposition method, i.e. Proper Orthogonal Decomposition (POD), is used to analyze the coherent structures induced with the particular

46 CFR 62.35-35 - Starting systems for internal-combustion engines.

Science.gov (United States)

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Starting systems for internal-combustion engines. 62.35-35 Section 62.35-35 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... Starting systems for internal-combustion engines. The starting systems for propulsion engines and for prime...

Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines

Science.gov (United States)

Schnauffer, Kurt

1932-01-01

The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined. Besides the determination of the influence of the above factors on combustion velocity, the degree of turbulence may also be determined. As a unit of reference in estimating the degree of turbulence, the intake velocity of the charge is chosen.

Control-oriented modeling of two-stroke diesel engines with exhaust gas recirculation for marine applications

OpenAIRE

Llamas, Xavier; Eriksson, Lars

2018-01-01

Large marine two-stroke diesel engines are widely used as propulsion systems for shipping worldwide and are facing stricter NOx emission limits. Exhaust gas recirculation is introduced to these engines to reduce the produced combustion NOx to the allowed levels. Since the current number of engines built with exhaust gas recirculation is low and engine testing is very expensive, a powerful alternative for developing exhaust gas recirculation controllers for such engines is to use control-orien...

Ischemic stroke in paediatrics - narrative review of the literature and two cases.

Science.gov (United States)

Klucka, Jozef; Stourac, Petr; Stoudek, Roman; Toukalkova, Michaela; Harazim, Hana; Kosinova, Martina; Stouracova, Alena; Mrlian, Andrej; Suk, Petr; Malaska, Jan

2017-03-01

Stroke is a rare condition in childhood with an estimated incidence of between 1.3-13/100.000 patients. Clinical manifestation and risk factors for paediatric stroke are different from those of adults. The uncommon incidence, age-associated difference and plethora of clinical symptoms make the diagnosis of such strokes extremely difficult and often delayed. The history and clinical examination should point to diseases or predisposing factors. Neuroimaging (DWI MR) is the golden standard for diagnosis of paediatric stroke and other investigations can be considered according to the clinical condition. Despite advances in paediatric stroke research and clinical care, questions remain unanswered regarding acute treatment, secondary prevention and rehabilitation. The treatment recommendations are mainly extrapolated from studies on adult populations. In the review authors summarized the clinical characteristics and diagnostic steps for stroke in children/adolescents based on the most recent international guidelines and practical directions for recognising and managing the child/adolescent with stroke in paediatric emergency. In the two case reports, we describe the clinical course in both stroke patients.

Nitrogen enriched combustion of a natural gas internal combustion engine to reduce NO.sub.x emissions

Science.gov (United States)

Biruduganti, Munidhar S.; Gupta, Sreenath Borra; Sekar, R. Raj; McConnell, Steven S.

2008-11-25

A method and system for reducing nitrous oxide emissions from an internal combustion engine. An input gas stream of natural gas includes a nitrogen gas enrichment which reduces nitrous oxide emissions. In addition ignition timing for gas combustion is advanced to improve FCE while maintaining lower nitrous oxide emissions.

Development of High Efficiency Clean Combustion Engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines

Energy Technology Data Exchange (ETDEWEB)

Marriott, Craig; Gonzalez, Manual; Russell, Durrett

2011-06-30

This report summarizes activities related to the revised STATEMENT OF PROJECT OBJECTIVES (SOPO) dated June 2010 for the Development of High-Efficiency Clean Combustion engine Designs for Spark-Ignition and Compression-Ignition Internal Combustion Engines (COOPERATIVE AGREEMENT NUMBER DE-FC26-05NT42415) project. In both the spark- (SI) and compression-ignition (CI) development activities covered in this program, the goal was to develop potential production-viable internal combustion engine system technologies that both reduce fuel consumption and simultaneously met exhaust emission targets. To be production-viable, engine technologies were also evaluated to determine if they would meet customer expectations of refinement in terms of noise, vibration, performance, driveability, etc. in addition to having an attractive business case and value. Prior to this activity, only proprietary theoretical / laboratory knowledge existed on the combustion technologies explored The research reported here expands and develops this knowledge to determine series-production viability. Significant SI and CI engine development occurred during this program within General Motors, LLC over more than five years. In the SI program, several engines were designed and developed that used both a relatively simple multi-lift valve train system and a Fully Flexible Valve Actuation (FFVA) system to enable a Homogeneous Charge Compression Ignition (HCCI) combustion process. Many technical challenges, which were unknown at the start of this program, were identified and systematically resolved through analysis, test and development. This report documents the challenges and solutions for each SOPO deliverable. As a result of the project activities, the production viability of the developed clean combustion technologies has been determined. At this time, HCCI combustion for SI engines is not considered production-viable for several reasons. HCCI combustion is excessively sensitive to control variables

Highly efficient 6-stroke engine cycle with water injection

Science.gov (United States)

Szybist, James P; Conklin, James C

2012-10-23

A six-stroke engine cycle having improved efficiency. Heat is recovered from the engine combustion gases by using a 6-stroke engine cycle in which combustion gases are partially vented proximate the bottom-dead-center position of the fourth stroke cycle, and water is injected proximate the top-dead-center position of the fourth stroke cycle.

Internal Combustion Engine Principles with Vehicle Applications

DEFF Research Database (Denmark)

Sorenson, Spencer C

The book is an introductory text on the subject of internal combustion engines, intended for use in engineering courses at the senior or introductory graduate student level. The focus in on describing the basic principles of engine operation on a broad basis, to provide a foundation for further...... exchange processes, combustion in different engine types, exhaust emissions, engine control including mean value engine models, pressure charging, fuels and fuel systems, balancing, friction, and heat transfer. In addition, methods to establish the connection between engine characteristics and vehicle...

Mapping the rehabilitation interventions of a community stroke team to the extended International Classification of Functioning, Disability and Health Core Set for Stroke.

Science.gov (United States)

Evans, Melissa; Hocking, Clare; Kersten, Paula

2017-12-01

This study aim was to evaluate whether the Extended International Classification of Functioning, Disability and Health Core Set for Stroke captured the interventions of a community stroke rehabilitation team situated in a large city in New Zealand. It was proposed that the results would identify the contribution of each discipline, and the gaps and differences in service provision to Māori and non-Māori. Applying the Extended International Classification of Functioning, Disability and Health Core Set for Stroke in this way would also inform whether this core set should be adopted in New Zealand. Interventions were retrospectively extracted from 18 medical records and linked to the International Classification of Functioning, Disability and Health and the Extended International Classification of Functioning, Disability and Health Core Set for Stroke. The frequencies of linked interventions and the health discipline providing the intervention were calculated. Analysis revealed that 98.8% of interventions provided by the rehabilitation team could be linked to the Extended International Classification of Functioning, Disability and Health Core Set for Stroke, with more interventions for body function and structure than for activities and participation; no interventions for emotional concerns; and limited interventions for community, social and civic life. Results support previous recommendations for additions to the EICSS. The results support the use of the Extended International Classification of Functioning, Disability and Health Core Set for Stroke in New Zealand and demonstrates its use as a quality assurance tool that can evaluate the scope and practice of a rehabilitation service. Implications for Rehabilitation The Extended International Classification of Functioning Disability and Health Core Set for Stroke appears to represent the stroke interventions of a community stroke rehabilitation team in New Zealand. As a result, researchers and clinicians may have

75 FR 37732 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2010-06-30

... National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines... hazardous air pollutants for existing stationary compression ignition reciprocating internal combustion... combustion engines. 40 CFR 63.6590 was amended by revising paragraphs (b)(1) and (3). Inadvertently...

Internal and Surface Phenomena in Heterogenous Metal Combustion

Science.gov (United States)

Dreizin, Edward L.

1997-01-01

The phenomenon of gas dissolution in burning metals was observed in recent metal combustion studies, but it could not be adequately explained by the traditional metal combustion models. The research reported here addresses heterogeneous metal combustion with emphasis on the processes of oxygen penetration inside burning metal and its influence on the metal combustion rate, temperature history, and disruptive burning. The unique feature of this work is the combination of the microgravity environment with a novel micro-arc generator of monodispersed metal droplets, ensuring repeatable formation and ignition of uniform metal droplets with a controllable initial temperature and velocity. Burning droplet temperature is measured in real time with a three wavelength pyrometer. In addition, particles are rapidly quenched at different combustion times, cross-sectioned, and examined using SEM-based techniques to retrieve the internal composition history of burning metal particles. When the initial velocity of a spherical particle is nearly zero, the microgravity environment makes it possible to study the flame structure, the development of flame nonsymmetry, and correlation of the flame shape with the heterogeneous combustion processes.

Internal and surface phenomena in metal combustion

Science.gov (United States)

Dreizin, Edward L.; Molodetsky, Irina E.; Law, Chung K.

1995-01-01

liquid fuel droplet combustion studies. In addition, the internal compositions of rapidly quenched metal particles will be analyzed using SEM technique. Such compositions are similar to those existing during the combustion and provide new insight on metal combustion processes. The results of this experimental work will be used to model the fundamental mechanisms of metal combustion. Preliminary experimental results on Al and Zr particle combustion at normal gravity are discussed here.

76 FR 12863 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2011-03-09

... National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines... combustion engines. The final rule was published on August 20, 2010. This direct final action amends certain... Emission Standards for Hazardous Air Pollutant for Stationary Reciprocating Internal Combustion Engines...

A predictive model of natural gas mixture combustion in internal combustion engines

Directory of Open Access Journals (Sweden)

Henry Espinoza

2007-05-01

Full Text Available This study shows the development of a predictive natural gas mixture combustion model for conventional com-bustion (ignition engines. The model was based on resolving two areas; one having unburned combustion mixture and another having combustion products. Energy and matter conservation equations were solved for each crankshaft turn angle for each area. Nonlinear differential equations for each phase’s energy (considering compression, combustion and expansion were solved by applying the fourth-order Runge-Kutta method. The model also enabled studying different natural gas components’ composition and evaluating combustion in the presence of dry and humid air. Validation results are shown with experimental data, demonstrating the software’s precision and accuracy in the results so produced. The results showed cylinder pressure, unburned and burned mixture temperature, burned mass fraction and combustion reaction heat for the engine being modelled using a natural gas mixture.

Dynamic estimator for determining operating conditions in an internal combustion engine

Science.gov (United States)

Hellstrom, Erik; Stefanopoulou, Anna; Jiang, Li; Larimore, Jacob

2016-01-05

Methods and systems are provided for estimating engine performance information for a combustion cycle of an internal combustion engine. Estimated performance information for a previous combustion cycle is retrieved from memory. The estimated performance information includes an estimated value of at least one engine performance variable. Actuator settings applied to engine actuators are also received. The performance information for the current combustion cycle is then estimated based, at least in part, on the estimated performance information for the previous combustion cycle and the actuator settings applied during the previous combustion cycle. The estimated performance information for the current combustion cycle is then stored to the memory to be used in estimating performance information for a subsequent combustion cycle.

Efficient energy recovering air inlet system for an internal combustion engine

NARCIS (Netherlands)

2011-01-01

An air inlet system (10) for an internal combustion engine (200) is provided. The air inlet system comprises an air intake port (20), an air output port (30) for providing air for a combustion chamber (202) of the combustion engine (200), and a turbine (40). The turbine (40) is situated in between

Efficient energy recovering air inlet system for an international combustion engine

NARCIS (Netherlands)

2013-01-01

An air inlet system (10) for an internal combustion engine (200) is provided. The air inlet system comprises an air intake port (20), an air output port (30) for providing air for a combustion chamber (202) of the combustion engine (200), and a turbine (40). The turbine (40) is situated in between

Internal combustion engines for alcohol motor fuels: a compilation of background technical information

Energy Technology Data Exchange (ETDEWEB)

Blaser, Richard

1980-11-01

This compilation, a draft training manual containing technical background information on internal combustion engines and alcohol motor fuel technologies, is presented in 3 parts. The first is a compilation of facts from the state of the art on internal combustion engine fuels and their characteristics and requisites and provides an overview of fuel sources, fuels technology and future projections for availability and alternatives. Part two compiles facts about alcohol chemistry, alcohol identification, production, and use, examines ethanol as spirit and as fuel, and provides an overview of modern evaluation of alcohols as motor fuels and of the characteristics of alcohol fuels. The final section compiles cross references on the handling and combustion of fuels for I.C. engines, presents basic evaluations of events leading to the use of alcohols as motor fuels, reviews current applications of alcohols as motor fuels, describes the formulation of alcohol fuels for engines and engine and fuel handling hardware modifications for using alcohol fuels, and introduces the multifuel engines concept. (LCL)

CAD/CAM/CAI Application for High-Precision Machining of Internal Combustion Engine Pistons

Directory of Open Access Journals (Sweden)

V. V. Postnov

2014-07-01

Full Text Available CAD/CAM/CAI application solutions for internal combustion engine pistons machining was analyzed. Low-volume technology of internal combustion engine pistons production was proposed. Fixture for CNC turning center was designed.

Development and validation of a 5 stroke engine for range extenders application

International Nuclear Information System (INIS)

Kéromnès, A.; Delaporte, B.; Schmitz, G.; Le Moyne, L.

2014-01-01

Highlights: • We have designed and built an innovative five stroke internal combustion engine. • The design includes an innovative exhaust gas management system, the smart waste gate. • The turbocharged port-injection spark ignition engine has a fuel conversion efficiency of 36%. - Abstract: A 5-stroke turbo-charged port-injection spark-ignition engine has been developed in the present study for use as a range extender or series-hybrid main power source. The development and the design of the engine are based on 0D/1D model and experimental results have been compared with the engine model. The 5-stroke engine is a three-cylinder in which two cylinders perform a four-stroke cycle and alternatively a second expansion of the burnt gases is performed in the third cylinder. The boost pressure delivered by the turbocharger is controlled by a particular innovative system called “smart wastegate”, different from a conventional wastegate, consisting in a variable valve timing of the two exhaust valves of the low pressure cylinder. The engine develops up to 40 kW for a speed range of 3500–4500 rpm. BSFC is 226 g/kW.h which corresponds to a fuel conversion efficiency of 36.1%. This efficiency can be achieved for an engine speed of 4000 rpm and a brake power of 32.5 kW, which are notable scores for an MPI two-valve per cylinder engine. Expected optimum should be below 217 g/kW.h BSFC and over 90 N.m torque. The engine has been tested over a wide range of conditions; model predictions and experimental results are compared and combustion efficiency increase discussed

Four-Stroke and Two-Stroke Marine Engines Comparison and Application

OpenAIRE

Eng. Waleed Alturki

2017-01-01

Marine engines have evolved a lot through time. From the earliest instances of rowing equipment to the advanced machinery, propulsion engines have become a critical part in the efficiency of marine vessels. These engines can be classified and selected using various characteristics and types, such as its operating cycle. Engines can come in either the four-stroke or the two-stroke version. Four-stroke engines are primarily used in cars, buses, and trucks due to their lower noise production and...

New type of microengine using internal combustion of hydrogen and oxygen

Science.gov (United States)

Svetovoy, Vitaly B.; Sanders, Remco G. P.; Ma, Kechun; Elwenspoek, Miko C.

2014-01-01

Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100 × 100 × 5 μm3 that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5–4 bar for a time of 100–400 μs in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines. PMID:24599052

New type of microengine using internal combustion of hydrogen and oxygen.

Science.gov (United States)

Svetovoy, Vitaly B; Sanders, Remco G P; Ma, Kechun; Elwenspoek, Miko C

2014-03-06

Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100 × 100 × 5 μm(3) that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5-4 bar for a time of 100-400 μs in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines.

Modeling the Distribution of Sulfur Compounds in a Large Two Stroke Diesel Engine

DEFF Research Database (Denmark)

Cordtz, Rasmus Lage; Schramm, Jesper; Andreasen, Anders

2013-01-01

In many years large low speed marine diesel engines have consumed heavy fuel oils with sulfur contents in the order of 2.5 - 4.5wt%. Present legislations require that the fuel sulfur is reduced and in near future the limit will be 0.5wt% globally. During combustion most of the sulfur is oxidized...... conditions and sulfur feed. This work presents a computational model of a large low speed two-stroke diesel engine where a 0D multi-zone approach including a detailed reaction mechanism is employed in order to investigate in cylinder formation of gaseous SO3 where fuel injection rates are determined using...... experimental pressure traces. Similarly to NO the SO3 is very sensitive to the rate that fresh air mixes with hot combustion products. Therefore a simple mixing rate is proposed and calibrated in order to meet experimental results of NO. Generally 3 - 5 % of the injected sulfur is oxidized to SO3...

Minimal algorithm for running an internal combustion engine

Science.gov (United States)

Stoica, V.; Borborean, A.; Ciocan, A.; Manciu, C.

2018-01-01

The internal combustion engine control is a well-known topic within automotive industry and is widely used. However, in research laboratories and universities the use of a control system trading is not the best solution because of predetermined operating algorithms, and calibrations (accessible only by the manufacturer) without allowing massive intervention from outside. Laboratory solutions on the market are very expensive. Consequently, in the paper we present a minimal algorithm required to start-up and run an internal combustion engine. The presented solution can be adapted to function on performance microcontrollers available on the market at the present time and at an affordable price. The presented algorithm was implemented in LabView and runs on a CompactRIO hardware platform.

Identification Of Damages Of Tribological Associations In Crankshaft And Piston Systems Of Two-Stroke Internal Combustion Engines Used As Main Propulsion In Sea-Going Vessels And Proposal Of Probabilistic Description Of Loads As Causes Of These Damages

Directory of Open Access Journals (Sweden)

Girtler Jerzy

2015-04-01

Full Text Available The article discusses damages of essential tribological associations in crankshaft and piston systems of large power two-stroke engines used as main engines, which take place during transport tasks performed by those ships. Difficulties are named which make preventing those damages impossible, despite the fact that the technical state of engines of this type is identified with the aid of complex diagnostic systems making use of advanced computer technology. It is demonstrated that one of causes of the damages is the lack of research activities oriented on recognising random properties of the loads leading to those damages. A proposal is made for the loads acting at a given time t on tribological associations in crankshaft and piston systems of internal combustion engines used as main engines to be considered as random variables Qt. At the same time the loads examined within a given time interval tr ≤ t ≤ tz would be considered stochastic processes {Q(t: t ≥ 0}. Essential properties of the loads of the abovementioned tribological associations are named and explained by formulating hypotheses which need empirical verification. Interval estimation is proposed for estimating the expected value E(Qt of the load Qt acting at time t. A relation is indicated between the mechanical load and the thermal load acting on tribological associations in the ship main engine crankshaft and piston system. A suggestion is formulated that a stochastic form of the relation between these types of load is to be searched for, rather than statistic relation, and a proposal is made to measure the intensity (strength of the stochastic relation using the Czuprow’s convergence coefficient.

Internal combustion engines history - a review

International Nuclear Information System (INIS)

Gaviria Rios, Jorge Enrique; Mora Guzman, Jorge Hernan; Agudelo, John Ramiro

2002-01-01

In this article, a chronological analysis of the technologies and events that any way influenced in the evolution of the internal combustion engine is done everything it through the observation of the works carried out for scientific empiric and engineers whose technical and conceptual value meant the motivation of other people for the search of a better development in this engineering field

Simulation Of The Internal-Combustion Engine

Science.gov (United States)

Zeleznik, Frank J.; Mcbride, Bonnie J.

1987-01-01

Program adapts to available information about particular engine. Mathematical model of internal-combustion engine constructed and implemented as computer program suitable for use on large digital computer systems. ZMOTTO program calculates Otto-cycle performance parameters as well as working-fluid compositions and properties throughout cycle for number of consecutive cycles and for variety of input parameters. Written in standard FORTRAN IV.

Virtual Instrument for Emissions Measurement of Internal Combustion Engines

Science.gov (United States)

Pérez, Armando; Montero, Gisela; Coronado, Marcos; García, Conrado; Pérez, Rubén

2016-01-01

The gases emissions measurement systems in internal combustion engines are strict and expensive nowadays. For this reason, a virtual instrument was developed to measure the combustion emissions from an internal combustion diesel engine, running with diesel-biodiesel mixtures. This software is called virtual instrument for emissions measurement (VIEM), and it was developed in the platform of LabVIEW 2010® virtual programming. VIEM works with sensors connected to a signal conditioning system, and a data acquisition system is used as interface for a computer in order to measure and monitor in real time the emissions of O2, NO, CO, SO2, and CO2 gases. This paper shows the results of the VIEM programming, the integrated circuits diagrams used for the signal conditioning of sensors, and the sensors characterization of O2, NO, CO, SO2, and CO2. VIEM is a low-cost instrument and is simple and easy to use. Besides, it is scalable, making it flexible and defined by the user. PMID:27034893

Virtual Instrument for Emissions Measurement of Internal Combustion Engines.

Science.gov (United States)

Pérez, Armando; Ramos, Rogelio; Montero, Gisela; Coronado, Marcos; García, Conrado; Pérez, Rubén

2016-01-01

The gases emissions measurement systems in internal combustion engines are strict and expensive nowadays. For this reason, a virtual instrument was developed to measure the combustion emissions from an internal combustion diesel engine, running with diesel-biodiesel mixtures. This software is called virtual instrument for emissions measurement (VIEM), and it was developed in the platform of LabVIEW 2010® virtual programming. VIEM works with sensors connected to a signal conditioning system, and a data acquisition system is used as interface for a computer in order to measure and monitor in real time the emissions of O2, NO, CO, SO2, and CO2 gases. This paper shows the results of the VIEM programming, the integrated circuits diagrams used for the signal conditioning of sensors, and the sensors characterization of O2, NO, CO, SO2, and CO2. VIEM is a low-cost instrument and is simple and easy to use. Besides, it is scalable, making it flexible and defined by the user.

International Practice in Care Provision for Post-stroke Visual Impairment.

Science.gov (United States)

Rowe, Fiona J

2017-09-01

This study sought to explore the practice of orthoptists internationally in care provision for poststroke visual impairment. Survey questions were developed and piloted with clinicians, academics, and users. Questions addressed types of visual problems, how these were identified, treated, and followed up, care pathways in use, links with other professions, and referral options. The survey was approved by the institutional ethical committee. The survey was accessed via a web link that was circulated through the International Orthoptic Association member professional organisations to orthoptists. Completed electronic surveys were obtained from 299 individuals. About one-third (35.5%) of orthoptists saw patients within 2 weeks of stroke onset and over half (55.5%) by 1 month post stroke. Stroke survivors were routinely assessed by 87%; over three-quarters in eye clinics. Screening tools were used by 11%. Validated tests were used for assessment of visual acuity (76.5%), visual field (68.2%), eye movement (80.9%), binocular vision (77.9%), and visual function (55.8%). Visual problems suspected by family or professionals were high (86.6%). Typical overall follow-up period of vision care was less than 3 months. Designated care pathways for stroke survivors with visual problems were used by 56.9% of orthoptists. Information on visual impairment was provided by 85.9% of orthoptists. In international orthoptic practice, there is general agreement on assessment and management of visual impairment in stroke populations. More than half of orthoptists reported seeing stroke survivors within 1 month of the stroke onset, typically in eye clinics. There was a high use of validated tests of visual acuity, visual fields, ocular motility, and binocular vision. Similarly there was high use of established treatment options including prisms, occlusion, compensatory strategies, and oculomotor training, appropriately targeted at specific types of visual conditions/symptoms. This

Concept of Six Stroke Engine

OpenAIRE

P.Naresh

2015-01-01

One of the most difficult challenges in engine technology today is the urgent need to increase engine thermal efficiency. Higher efficiencies mean less fuel consumption and lower atmospheric emissions per unit of work produced by the engine. In 1862 a Frenchman Alphouse Beau de Rochas gives his theory regarding the ideal cycle of the internal combustion engine. This theory is applied by a German engineer named Nikolaus A. Otto, who firstly built a successful four-stroke SI engine in 1876. The...

40 CFR 60.4210 - What are my compliance requirements if I am a stationary CI internal combustion engine manufacturer?

Science.gov (United States)

2010-07-01

... I am a stationary CI internal combustion engine manufacturer? 60.4210 Section 60.4210 Protection of... CI internal combustion engine manufacturer? (a) Stationary CI internal combustion engine... certified to the standards in 40 CFR part 1039. (b) Stationary CI internal combustion engine manufacturers...

The Combination of Internal-Combustion Engine and Gas Turbine

Science.gov (United States)

Zinner, K.

1947-01-01

While the gas turbine by itself has been applied in particular cases for power generation and is in a state of promising development in this field, it has already met with considerable success in two cases when used as an exhaust turbine in connection with a centrifugal compressor, namely, in the supercharging of combustion engines and in the Velox process, which is of particular application for furnaces. In the present paper the most important possibilities of combining a combustion engine with a gas turbine are considered. These "combination engines " are compared with the simple gas turbine on whose state of development a brief review will first be given. The critical evaluation of the possibilities of development and fields of application of the various combustion engine systems, wherever it is not clearly expressed in the publications referred to, represents the opinion of the author. The state of development of the internal-combustion engine is in its main features generally known. It is used predominantly at the present time for the propulsion of aircraft and road vehicles and, except for certain restrictions due to war conditions, has been used to an increasing extent in ships and rail cars and in some fields applied as stationary power generators. In the Diesel engine a most economical heat engine with a useful efficiency of about 40 percent exists and in the Otto aircraft engine a heat engine of greatest power per unit weight of about 0.5 kilogram per horsepower.

Fuel injector nozzle for an internal combustion engine

Science.gov (United States)

Cavanagh, Mark S.; Urven, Jr., Roger L.; Lawrence, Keith E.

2008-11-04

A direct injection fuel injector includes a nozzle tip having a plurality of passages allowing fluid communication between an inner nozzle tip surface portion and an outer nozzle tip surface portion and directly into a combustion chamber of an internal combustion engine. A first group of the passages have inner surface apertures located substantially in a first common plane. A second group of the passages have inner surface apertures located substantially in at least a second common plane substantially parallel to the first common plane. The second group has more passages than the first group.

Internal combustion engine run on biogas is a potential solution to meet Indonesia emission target

Science.gov (United States)

Ambarita, Himsar

2017-09-01

Indonesia has released two different Greenhouse Gas (GHG) emissions reduction targets. The first target, released in 2009, is reduction GHG emissions 26% from Business-as-Usual (BAU) level using own budget and up 41% if supported international aids by 2020. The second target is reduction 29% and 41% from BAU by 2030 using own budget and with international support, respectively. In this paper, the BAU emissions and emissions reduction target of these two targets are elaborated. In addition, the characteristics of emissions from transportation sector are discussed. One of the potential mitigation actions is switching fuel in transportation sector. The results the most promising mitigation action in the transportation is switching oil fuel with biofuel. The Government of Indonesia (GoI) focuses on using biodiesel and bioethanol to run internal combustion engine in transportation sector and biogas is aimed to fuel power plant unit. However, there is very limited of success stories on using biogas in the power plant. The barriers and challenges will be discussed here. It is suggested to run internal combustion engine with biogas.

New type of microengine using internal combustion of hydrogen and oxygen

NARCIS (Netherlands)

Svetovoy, Vitaly; Sanders, Remco G.P.; Ma, Kechun; Elwenspoek, Michael Curt

2014-01-01

Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we

Design, calibration and error analysis of instrumentation for heat transfer measurements in internal combustion engines

Science.gov (United States)

Ferguson, C. R.; Tree, D. R.; Dewitt, D. P.; Wahiduzzaman, S. A. H.

1987-01-01

The paper reports the methodology and uncertainty analyses of instrumentation for heat transfer measurements in internal combustion engines. Results are presented for determining the local wall heat flux in an internal combustion engine (using a surface thermocouple-type heat flux gage) and the apparent flame-temperature and soot volume fraction path length product in a diesel engine (using two-color pyrometry). It is shown that a surface thermocouple heat transfer gage suitably constructed and calibrated will have an accuracy of 5 to 10 percent. It is also shown that, when applying two-color pyrometry to measure the apparent flame temperature and soot volume fraction-path length, it is important to choose at least one of the two wavelengths to lie in the range of 1.3 to 2.3 micrometers. Carefully calibrated two-color pyrometer can ensure that random errors in the apparent flame temperature and in the soot volume fraction path length will remain small (within about 1 percent and 10-percent, respectively).

Experimental Evaluation of a Method for Turbocharging Four-Stroke, Single Cylinder, Internal Combustion Engines

Science.gov (United States)

Buchman, Michael; Winter, Amos

2015-11-01

Turbocharging an engine increases specific power, improves fuel economy, reduces emissions, and lowers cost compared to a naturally aspirated engine of the same power output. These advantages make turbocharging commonplace for multi-cylinder engines. Single cylinder engineers are not commonly turbocharged due to the phase lag between the exhaust stroke, which powers the turbocharger, and the intake stroke, when air is pumped into the engine. Our proposed method of turbocharging single cylinder engines is to add an ``air capacitor'' to the intake manifold, an additional volume that acts as a buffer to store compressed air between the exhaust and intake strokes, and smooth out the pressure pulses from the turbocharger. This talk presents experimental results from a single cylinder, turbocharged diesel engine fit with various sized air capacitors. Power output from the engine was measured using a dynamometer made from a generator, with the electrical power dissipated with resistive heating elements. We found that intake air density increases with capacitor size as theoretically predicted, ranging from 40 to 60 percent depending on heat transfer. Our experiment was able to produce 29 percent more power compared to using natural aspiration. These results validated that an air capacitor and turbocharger may be a simple, cost effective means of increasing the power density of single cylinder engines.

Influence of injector technology on injection and combustion development - Part 2: Combustion analysis

Energy Technology Data Exchange (ETDEWEB)

Payri, R.; Salvador, F.J.; Gimeno, J.; Morena, J. de la [CMT-Motores Termicos, Universidad Politecnica de Valencia, Camino de Vera s/n, E-46022 (Spain)

2011-04-15

The influence of injection technology on the fuel-air mixing process and the combustion development are analyzed by means of visualization techniques. For this purpose, two injectors (one solenoid and one piezoelectric) are characterized using an optical accessible two stroke engine. Visualization of liquid penetration has allowed the measurement of the stabilized liquid length, which is related with the efficiency of fuel-air mixing process. A theoretical derivation is used in order to relate this liquid length with chamber conditions, as well as to make a temporal analysis of these phenomena. After this, natural flame emission and chemiluminescence techniques are carried out. These results indicate that the piezoelectric system has a more efficient fuel-air mixing and combustion, reducing the characteristic times as well as soot formation. Finally, a correlation for the ignition delay of the two systems is obtained. (author)

Coal-water slurry fuel internal combustion engine and method for operating same

Science.gov (United States)

McMillian, Michael H.

1992-01-01

An internal combustion engine fueled with a coal-water slurry is described. About 90 percent of the coal-water slurry charge utilized in the power cycle of the engine is directly injected into the main combustion chamber where it is ignited by a hot stream of combustion gases discharged from a pilot combustion chamber of a size less than about 10 percent of the total clearance volume of main combustion chamber with the piston at top dead center. The stream of hot combustion gases is provided by injecting less than about 10 percent of the total coal-water slurry charge into the pilot combustion chamber and using a portion of the air from the main combustion chamber that has been heated by the walls defining the pilot combustion chamber as the ignition source for the coal-water slurry injected into the pilot combustion chamber.

Carbon/Carbon Pistons for Internal Combustion Engines

Science.gov (United States)

Taylor, A. H.

1986-01-01

Carbon/carbon piston performs same function as aluminum pistons in reciprocating internal combustion engines while reducing weight and increasing mechanical and thermal efficiencies of engine. Carbon/carbon piston concept features low piston-to-cylinder wall clearance - so low piston rings and skirts unnecessary. Advantages possible by negligible coefficient of thermal expansion of carbon/carbon.

Mitigating the effect of siloxanes on internal combustion engines using landfill gasses

Science.gov (United States)

Besmann, Theodore M

2014-01-21

A waste gas combustion method that includes providing a combustible fuel source, in which the combustible fuel source is composed of at least methane and siloxane gas. A sodium source or magnesium source is mixed with the combustible fuel source. Combustion of the siloxane gas of the combustible fuel source produces a silicon containing product. The sodium source or magnesium source reacts with the silicon containing product to provide a sodium containing glass or sodium containing silicate, or a magnesium containing silicate. By producing the sodium containing glass or sodium containing silicate, or the magnesium containing silicate, or magnesium source for precipitating particulate silica instead of hard coating, the method may reduce or eliminate the formation of silica deposits within the combustion chamber and the exhaust components of the internal combustion engine.

An International Standard Set of Patient-Centered Outcome Measures After Stroke

NARCIS (Netherlands)

Salinas, J. (Joel); Sprinkhuizen, S.M. (Sara M.); Ackerson, T. (Teri); Bernhardt, J. (Julie); Davie, C. (Charlie); George, M.G. (Mary G.); Gething, S. (Stephanie); Kelly, A.G. (Adam G.); Lindsay, P. (Patrice); Liu, L. (Liping); Martins, S.C.O. (Sheila C.O.); Morgan, L. (Louise); B. Norrving (Bo); Ribbers, G.M. (Gerard M.); Silver, F.L. (Frank L.); Smith, E.E. (Eric E.); Williams, L.S. (Linda S.); Schwamm, L.H. (Lee H.)

2015-01-01

markdownabstract__BACKGROUND AND PURPOSE:__ Value-based health care aims to bring together patients and health systems to maximize the ratio of quality over cost. To enable assessment of healthcare value in stroke management, an international standard set of patient-centered stroke outcome measures

Study of Second Generation Biofuels in Internal Combustion Engines

Energy Technology Data Exchange (ETDEWEB)

Kannan, Dhandapani

2012-07-01

This research focused on the fuel modification approach to emissions reduction. In order to address the food-fuel-fiber conflicts, the alternative fuel has to have its source preferably from non-food crops. Therefore, non-food-crop-based blends of biomass-derived bio diesel (BD), derived from Jatropha curcus, is considered a good choice. However this bio-diesel has a high viscosity and thereby problems associated with its spray characteristics. In order to tide over these challenges, it is blended with low-viscosity fuels such as ethanol or Fischer-Tropsch (FT) synthetic diesel. This research studied the feasibility and usage of bio-fuels in IC engines to address the aforesaid concerns, understand what the fundamentally acceptable emission levels are and also determine the optimal blending limits of bio-fuels. In this context, the experimental works are carried out as two cases. First, the experimental investigations on blends of Fischer-Tropsch (FT) synthetic diesel and Jatropha methyl ester (JME), as fuel in a diesel engine, are carried out. The JME was produced by the trans-esterification process and the blends are tested against EN14214, or in some cases, ASTM standards. The volumetric blending percentages of BD to FT fuel are 0:100, 25:75, 50:50, 75:25 and 100:0 respectively. Fourier Transform Infra-Red (FTIR) spectroscopy results indicate that the BD and FT fuels are mainly aliphatic and ester compounds. The gas chromatography (GC) result shows that the neat BD (B100) contains more than 97% ester. The experiment was conducted with a four-stroke, six-cylinder, turbo-charged, direct injection (DI) diesel engine with an optimum engine speed of 1450 rpm and a dynamic fuel injection timing of 20 crank angle degrees (CAD) before the top dead centre (TDC). The experimental results showed that the exhaust emissions including carbon monoxide (CO), total unburnt hydrocarbon (THC), smoke, total particulate matter (TPM) and oxides of nitrogen (NOx) were reduced with FT

3rd International Conference on Numerical Combustion

CERN Document Server

Larrouturou, Bernard; Numerical Combustion

1989-01-01

Interest in numerical combustion is growing among applied mathematicians, physicists, chemists, engine manufacturers and many industrialists. This proceedings volume contains nine invited lectures and twenty seven contributions carefully selected by the editors. The major themes are numerical simulation of transsonic and supersonic combustion phenomena, the study of supersonic reacting mixing layers, and turbulent combustion. Emphasis is laid on hyperbolic models and on numerical simulations of hydrocarbon planes with a complete set of chemical reactions carried out in two-dimensional geometries as well as on complex reactive flow simulations.

78 FR 14457 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2013-03-06

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 60 and 63 [EPA-HQ-OAR-2008-0708, FRL-9756-4] RIN 2060-AQ58 National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines; New Source Performance Standards for Stationary Internal Combustion Engines Correction In rule...

Exhaust gas afterburner for internal combustion engines

Energy Technology Data Exchange (ETDEWEB)

Haertel, G

1977-05-12

The invention pertains to an exhaust gas afterburner for internal combustion engines, with an auxiliary fuel device arranged upstream from the afterburner proper and controlled by the rotational speed of the engine, which is additionally controlled by an oxygen or carbon monoxide sensor. The catalytic part of the afterburner, together with a rotochamber, is a separate unit.

Post-stroke depression among stroke survivors attending two ...

African Journals Online (AJOL)

Background: The burden of stroke worldwide is increasing rapidly. There is paucity of data on post-stroke depression (PSD) among stroke survivors in Uganda, despite the high prevalence of PSD reported elsewhere. Methods: In a cross-sectional study, we assessed adult participants with confirmed first stroke with a ...

Effects of Scavenging System Configuration on In-Cylinder Air Flow Organization of an Opposed-Piston Two-Stroke Engine

OpenAIRE

Fukang Ma; Changlu Zhao; Fujun Zhang; Zhenfeng Zhao; Shuanlu Zhang

2015-01-01

In-cylinder air flow is very important from the point of view of mixture formation and combustion. In this direction, intake chamber structure and piston crown shape play a very crucial role for in-cylinder air pattern of opposed-piston two-stroke (OP2S) engines. This study is concerned with the three-dimensional (3D) computational fluid dynamics (CFD) analysis of in-cylinder air motion coupled with the comparison of predicted results with the zero-dimensional (0D) parametric model. Three con...

Fundamental test results of a hydraulic free piston internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Hibi, A.; Ito, T. [Toyohashi University of Technology (Japan). Dept. of Mechanical Engineering

2004-10-01

The hydraulic free piston internal combustion engine pump that has been constructed and tested in this work is the opposed piston, two-stroke cycle, uniflow scavenging, direct fuel injection, and compression ignition type. The opposed engine pistons reciprocate the hydraulic pump pistons directly and the hydraulic power to be used in the hydraulic motors is generated. The hydraulic pressure generated is substantially constant. The opposed free pistons rest after every gas cycle and hydraulic power is continuously supplied by a hydraulic accumulator during the free pistons' rest. The smaller the hydraulic flow output, the longer the duration of the rest. Every gas cycle is performed under a fixed working condition independent of hydraulic power output. The test results in this work indicate that the number of gas cycles per second of the free piston engine pump is directly proportional to hydraulic flow output. The opposed free pistons operate every 53.2 s when hydraulic flow output is 1.02 cm{sup 3}/s; at that time hydraulic power output is 0.0124 kW. Hydraulic thermal efficiency, the ratio of hydraulic energy produced to fuel energy consumed, has been measured in the range 0.0124 kW to 4.88 kW of hydraulic power output and it has become clear that hydraulic thermal efficiency in this range is constant. The measured value of hydraulic thermal efficiency is 31 per cent. It has been demonstrated that hydraulic thermal efficiency is kept constant even if hydraulic power output is very small. (author)

International cooperative research project between NEDO and NASA on advanced combustion science utilizing microgravity

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

This paper describes an international cooperative research project between NEDO and NASA on advanced combustion science utilizing microgravity. In June, 1994, NEDO and NASA reached a basic agreement with each other about this cooperative R and D on combustion under microgravity conditions. In fiscal 2000, Japan proposed an experiment using the drop tower facilities and parabolic aircraft at NASA Glen Research Center and at JAMIC (Japan Microgravity Center). In other words, the proposals from Japan included experiments on combustion of droplets composed of diversified fuels under different burning conditions (vaporization), flame propagation in smoldering porous materials and dispersed particles under microgravity conditions, and control of interactive combustion of two droplets by acoustical and electrical perturbations. Additionally proposed were experiments on effect of low external air flow on solid material combustion under microgravity, and sooting and radiation effects on the burning of large droplets under microgravity conditions. This report gives an outline of the results of these five cooperative R and D projects. The experiments were conducted under ordinary normal gravity and microgravity conditions, with the results compared and examined mutually. (NEDO)

Internal combustion engine

Science.gov (United States)

Baker, Quentin A.; Mecredy, Henry E.; O'Neal, Glenn B.

1991-01-01

An improved engine is provided that more efficiently consumes difficult fuels such as coal slurries or powdered coal. The engine includes a precombustion chamber having a portion thereof formed by an ignition plug. The precombustion chamber is arranged so that when the piston is proximate the head, the precombustion chamber is sealed from the main cylinder or the main combustion chamber and when the piston is remote from the head, the precombustion chamber and main combustion chamber are in communication. The time for burning of fuel in the precombustion chamber can be regulated by the distance required to move the piston from the top dead center position to the position wherein the precombustion chamber and main combustion chamber are in communication.

Inequities in access to inpatient rehabilitation after stroke: an international scoping review.

Science.gov (United States)

Lynch, Elizabeth A; Cadilhac, Dominique A; Luker, Julie A; Hillier, Susan L

2017-12-01

Background Inequities in accessing inpatient rehabilitation after stroke have been reported in many countries and impact on patient outcomes. Objective To explore variation in international recommendations regarding which patients should receive inpatient rehabilitation after stroke and to describe reported access to rehabilitation. Methods A scoping review was conducted to identify clinical guidelines with recommendations regarding which patients should access inpatient rehabilitation after stroke, and data regarding the proportion of patients accessing stroke rehabilitation. Four bibliographic databases and grey literature were searched. Results Twenty-eight documents were included. Selection criteria for post-acute inpatient rehabilitation were identified for 14 countries or regions and summary data on the proportion of patients receiving inpatient rehabilitation were identified for 14 countries. In Australia, New Zealand, and the United Kingdom, it is recommended that all patients with stroke symptoms should access rehabilitation, whereas guidelines from the United States, Canada, and Europe did not consistently recommend rehabilitation for people with severe stroke. Access to inpatient rehabilitation ranged from 13% in Sweden to 57% in Israel. Differences in availability of early supported discharge/home rehabilitation programs and variations in reporting methods may influence the ability to reliably compare access to rehabilitation between regions. Conclusion Recommendations regarding which patients with moderate and severe strokes should access ongoing rehabilitation are inconsistent. Clinical practice guidelines from different countries regarding post-stroke rehabilitation do not always reflect the evidence regarding the likely benefits to people with stroke. Inequity in access to rehabilitation after stroke is an international issue.

Experimental results with hydrogen fueled internal combustion engines

Science.gov (United States)

De Boer, P. C. T.; Mclean, W. J.; Homan, H. S.

1975-01-01

The paper focuses on the most important experimental findings for hydrogen-fueled internal combustion engines, with particular reference to the application of these findings to the assessment of the potential of hydrogen engines. Emphasis is on the various tradeoffs that can be made, such as between maximum efficiency, maximum power, and minimum NO emissions. The various possibilities for induction and ignition are described. Some projections are made about areas in which hydrogen engines may find their initial application and about optimum ways to design such engines. It is shown that hydrogen-fueled reciprocal internal combustion engines offer important advantages with respect to thermal efficiency and exhaust emissions. Problems arising from preignition can suitably be avoided by restricting the fuel-air equivalence ratio to values below about 0.5. The direct cylinder injection appears to be a very attractive way to operate the engine, because it combines a wide range of possible power outputs with a high thermal efficiency and very low NO emissions at part loads.

Direct Fuel Injection of LPG in Small Two-Stroke Engines

OpenAIRE

Yew Heng Teoh; Horizon Gitano-Briggs

2011-01-01

The commonly used carburetted two-stroke engines in developing countries have high exhaust emission and poor fuel efficiency. To meet more rigid emissions requirements, two-stroke vehicles are typically phase out in favour of four-stroke engines. The problems of ubiquitous legacy two-stroke vehicles remain unsolved by these measures and they are likely to be a major source of transport for many years to come. A number of technologies are available for solving the problems associated with two-...

Comparative evaluation of a two stroke compressed natural gas mixer design using simulation and experimental techniques

Energy Technology Data Exchange (ETDEWEB)

Ramasamy, D.; Bakar, R.A.; Rahim, M.F.; Noor, M.M. [Malaysia Pahang Univ., Pahang (Malaysia). Automotive Focus Group

2008-07-01

A study was conducted in which a two-stroke engine was converted for use with bi-fuel, notably compressed natural gas and gasoline. The excessive by-products generated by two-stroke engine combustion can be attributed to the inefficient combustion process. This prototype uniflow-type single-cylinder engine was equipped with a bi-fuel conversion system. A dedicated mixer was also developed to meter the gaseous fuel through the engine intake system. It was designed to meet air and fuel requirement similar to its gasoline counterpart. The mixer was modeled to obtain optimum orifice diameter using three different sizes of 14, 16 and 18 mm respectively. A standard computational fluid dynamics (CFD) software package was used to simulate the flow. A pressure reading was obtained during the prototype test. The drop in pressure across the venturi was shown to be an important parameter as it determined the actual fuel-air ratio in the actual engine. A good agreement of CFD outputs with that of the experimental outputs was recorded. The experimental technique validated the pressure distribution predicted by CFD means on the effects of the three insert rings in the CNG mixer. The simulation exercise can be used to predict the amount of CNG consumed by the engine. It was concluded that the 14 mm throat ring was best suited for the CNG mixer because it provided the best suction. Once the mixer is tested on a real engine, it will clear any doubts as to whether the throat can function at high engine speeds. 5 refs., 3 tabs., 8 figs.

Using Alcohols as an Alternative Fuel in Internal Combustion Engines

Directory of Open Access Journals (Sweden)

Salih ÖZER

2014-04-01

Full Text Available This study summarizes the studies on alcohol use in internal combustion engines nature. Nowadays, alcohol is used in internal combustion engines sometimes in order to reduce emissions and sometimes as an alternative fuel. Even vehicle manufacturers are producing and launching vehicles that are running directly with alcohol. Many types of pure alcohol that can be used on vehicles are available on the world. Using all of these types of alcohol led to the formation of engine emissions and power curves. The studies reveal that these changes are because of the physical and chemical characteristics of alcohols. Thıs study tries to explain what kind of conclusions the physical and chemical properties cause

Internal combustion engine cylinder-to-cylinder balancing with balanced air-fuel ratios

Science.gov (United States)

Harris, Ralph E.; Bourn, Gary D.; Smalley, Anthony J.

2006-01-03

A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

Chemistry and the Internal Combustion Engine II: Pollution Problems.

Science.gov (United States)

Hunt, C. B.

1979-01-01

Discusses pollution problems which arise from the use of internal combustion (IC) engines in the United Kingdom (UK). The IC engine exhaust emissions, controlling IC engine pollution in the UK, and some future developments are also included. (HM)

Air-steam hybrid engine : an alternative to internal combustion.

Science.gov (United States)

2011-03-01

In this Small Business Innovation Research (SBIR) Phase 1 project, an energy-efficient air-steam propulsion system has been developed and patented, and key performance attributes have been demonstrated to be superior to those of internal combustion e...

Analysis of an Internal Combustion Engine Using Porous Foams for Thermal Energy Recovery

Directory of Open Access Journals (Sweden)

Mehdi Ali Ehyaei

2016-03-01

Full Text Available Homogeneous and complete combustion in internal combustion engines is advantageous. The use of a porous foam in the exhaust gas in an engine cylinder for heat recovery is examined here with the aim of reducing engine emissions. The internal combustion engine with a porous core regenerator is modeled using SOPHT software, which solved the differential equations for the thermal circuit in the engine. The engine thermal efficiency is observed to increase from 43% to 53% when the porous core regenerator is applied. Further, raising the compression ratio causes the peak pressure and thermal efficiency to increase, e.g., increasing the compression ratio from 13 to 15 causes the thermal efficiency and output work to increase from 53% to 55% and from 4.86 to 4.93 kJ, respectively. The regenerator can also be used as a catalytic converter for fine particles and some other emissions. The regenerator oxidizes unburned hydrocarbons. Meanwhile, heat recovered from the exhaust gases can reduce fuel consumption, further reducing pollutant emissions from the internal combustion engine.

The dynamic interaction between combustible renewables and waste consumption and international tourism: the case of Tunisia.

Science.gov (United States)

Ben Jebli, Mehdi; Ben Youssef, Slim; Apergis, Nicholas

2015-08-01

This paper employs the autoregressive distributed lag (ARDL) bounds methodological approach to investigate the relationship between economic growth, combustible renewables and waste consumption, carbon dioxide (CO2) emissions, and international tourism for the case of Tunisia spanning the period 1990-2010. The results from the Fisher statistic of both the Wald test and the Johansen test confirm the presence of a long-run relationship among the variables under investigation. The stability of estimated parameters has been tested, while Granger causality tests recommend a short-run unidirectional causality running from economic growth and combustible renewables and waste consumption to CO2 emissions, a bidirectional causality between economic growth and combustible renewables and waste consumption and unidirectional causality running from economic growth and combustible renewables and waste consumption to international tourism. In the long-run, the error correction terms confirm the presence of bidirectional causality relationships between economic growth, CO2 emissions, combustible renewables and waste consumption, and international tourism. Our long-run estimates show that combustible renewables and waste consumption increases international tourism, and both renewables and waste consumption and international tourism increase CO2 emissions and output. We recommend that (i) Tunisia should use more combustible renewables and waste energy as this eliminates wastes from touristic zones and increases the number of tourist arrivals, leading to economic growth, and (ii) a fraction of this economic growth generated by the increase in combustible renewables and waste consumption should be invested in clean renewable energy production (i.e., solar, wind, geothermal) and energy efficiency projects.

Influence of biofuels usage in internal combustion engines of agricultural tractors on output parametrs

Directory of Open Access Journals (Sweden)

Tomáš Šmerda

2010-01-01

Full Text Available Application of alternative fuels brings the social benefits in terms of reducing dependence on oil industry and its products as well as decreasing of damage of the environment together with using of na­tu­ral resources, especially in field of renewable energy resources. The use of biofuels is the most important part of energy strategy in European Union, whose member states have agreed the content of biofuels will achieve 5.75% of the total energy sum of fuel for transport purposes in 2010. Operation of internal combustion engine fueled by RME brings environmental benefits as described several authors in analysis of the life cycle. The contribution deals with technical difficulties of the RME usage in internal combustion engine used in agricultural tractors. Different fuel causes different process of combustion which means changes in output power and pollution. The aim of this experiment was to determine these effects. Experimental work was divided into two parts according to various fuel systems. The first tractor was equipped with mechanical injection system, the second one was provided with common-rail fuel system. The test procedures consisted of measurement of power- torque curves where the engine load was created by Eddy current dynamometer. Exhaust gas analyzer sampled the pollution of carbon monoxide, carbon dioxide and hydrocarbons as the most important indicators of combustion process.

40 CFR Appendix A to Subpart A of... - State Regulation of Nonroad Internal Combustion Engines

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false State Regulation of Nonroad Internal Combustion Engines A Appendix A to Subpart A of Part 89 Protection of Environment ENVIRONMENTAL PROTECTION... Nonroad Internal Combustion Engines This appendix sets forth the Environmental Protection Agency's (EPA's...

40 CFR 60.4241 - What are my compliance requirements if I am a manufacturer of stationary SI internal combustion...

Science.gov (United States)

2010-07-01

... I am a manufacturer of stationary SI internal combustion engines participating in the voluntary... I am a manufacturer of stationary SI internal combustion engines participating in the voluntary... internal combustion engines with a maximum engine power greater than 19 KW (25 HP) that do not use gasoline...

Some Factors Affecting Combustion in an Internal-Combustion Engine

Science.gov (United States)

Rothrock, A M; Cohn, Mildred

1936-01-01

An investigation of the combustion of gasoline, safety, and diesel fuels was made in the NACA combustion apparatus under conditions of temperature that permitted ignition by spark with direct fuel injection, in spite of the compression ratio of 12.7 employed. The influence of such variables as injection advance angle, jacket temperature, engine speed, and spark position was studied. The most pronounced effect was that an increase in the injection advance angle (beyond a certain minimum value) caused a decrease in the extent and rate of combustion. In almost all cases combustion improved with increased temperature. The results show that at low air temperatures the rates of combustion vary with the volatility of the fuel, but that at high temperatures this relationship does not exist and the rates depend to a greater extent on the chemical nature of the fuel.

[Two simple questions to diagnose post-stroke depression].

Science.gov (United States)

Nolte, C H; Müller-Nordhorn, J; Jungehülsing, G J; Rossnagel, K; Reich, A; Roll, S; Laumeier, I; Beerfelde, D; Willich, S N; Villringer, A

2006-05-01

Many patients develop a depression after having suffered a stroke. Such a Post-Stroke Depression (PSD) impairs rehabilitation and quality of life. PSD is underdiagnosed in spite of available treatment. Several questionnaires have been created to diagnose a PSD. But questionnaires have been considered cumbersome and time-consuming. The aim of this study was to find out whether two simple, standardised questions will identify those stroke patients, who have developed a PSD. The two case-finding questions and the Beck Depression Inventory (BDI) were sent to patients of the Berlin Acute Stroke Study (BASS) four years after their stroke. Incomplete questionnaires were complemented via mail or telephone. Severity of depression was assessed by means of BDI. Out of 211 patients, 199 responded to the questionnaire (94 %). 193 questionnaires were complete (97 %). Forty-two patients affirmed both case-finding questions (22 %). Compared to patients, who did not affirm both questions, these patients had a higher BDI score (19 +/- 8 vs. 7 +/- 5; p two questions were 89 % and 90 %, respectively. The positive and negative predictive value were 60 % and 98 % respectively. The number of confirmed questions (0, 1, 2) correlated well with the BDI score (r (2) = 0.67, p Two standardized questions can identify patients with PSD for further diagnostic evaluation and therapy. Diagnosis of PSD might be facilitated by using them as screening instrument.

Construction of a Direct Water-Injected Two-Stroke Engine for Phased Direct Fuel Injection-High Pressure Charging Investigations

Science.gov (United States)

Somsel, James P.

1998-01-01

The development of a water injected Orbital Combustion Process (OCP) engine was conducted to assess the viability of using the powerplant for high altitude NASA aircraft and General Aviation (GA) applications. An OCP direct fuel injected, 1.2 liter, three cylinder, two-stroke engine has been enhanced to independently inject water directly into the combustion chamber. The engine currently demonstrates low brake specific fuel consumption capability and an excellent power to weight ratio. With direct water injection, significant improvements can be made to engine power, to knock limits/ignition advance timing, and to engine NO(x) emissions. The principal aim of the testing was to validate a cyclic model developed by the Systems Analysis Branch at NASA Ames Research Center. The work is a continuation of Ames' investigations into a Phased Direct Fuel Injection Engine with High Pressure Charging (PDFI-ITPC).

Powertrain sizing of electrically supercharged internal combustion engine vehicles

NARCIS (Netherlands)

Murgovski, N.; Marinkov, S.; Hilgersom, D.; de Jager, B.; Steinbuch, M.; Sjöberg, J.

2015-01-01

We assess the concept of electrically supercharged internal combustion engines, where the supercharger, consisting of a compressor and an electric motor, draws electric power from a buffer (a battery or a supercapacitor). In particular, we investigate the scenario of downsizing the engine, while

40 CFR 60.4238 - What are my compliance requirements if I am a manufacturer of stationary SI internal combustion...

Science.gov (United States)

2010-07-01

... I am a manufacturer of stationary SI internal combustion engines â¤19 KW (25 HP) or a manufacturer... Standards of Performance for Stationary Spark Ignition Internal Combustion Engines Compliance Requirements... SI internal combustion engines ≤19 KW (25 HP) or a manufacturer of equipment containing such engines...

40 CFR 60.4239 - What are my compliance requirements if I am a manufacturer of stationary SI internal combustion...

Science.gov (United States)

2010-07-01

... I am a manufacturer of stationary SI internal combustion engines >19 KW (25 HP) that use gasoline or... NEW STATIONARY SOURCES Standards of Performance for Stationary Spark Ignition Internal Combustion... manufacturer of stationary SI internal combustion engines >19 KW (25 HP) that use gasoline or a manufacturer of...

40 CFR 60.4240 - What are my compliance requirements if I am a manufacturer of stationary SI internal combustion...

Science.gov (United States)

2010-07-01

... I am a manufacturer of stationary SI internal combustion engines >19 KW (25 HP) that are rich burn... I am a manufacturer of stationary SI internal combustion engines >19 KW (25 HP) that are rich burn..., and must test their engines as specified in that part. Stationary SI internal combustion engine...

40 CFR 60.4242 - What other requirements must I meet if I am a manufacturer of stationary SI internal combustion...

Science.gov (United States)

2010-07-01

... I am a manufacturer of stationary SI internal combustion engines or equipment containing stationary SI internal combustion engines or a manufacturer of equipment containing such engines? 60.4242... Ignition Internal Combustion Engines Compliance Requirements for Manufacturers § 60.4242 What other...

Observing and modeling nonlinear dynamics in an internal combustion engine

International Nuclear Information System (INIS)

Daw, C.S.; Kennel, M.B.; Finney, C.E.; Connolly, F.T.

1998-01-01

We propose a low-dimensional, physically motivated, nonlinear map as a model for cyclic combustion variation in spark-ignited internal combustion engines. A key feature is the interaction between stochastic, small-scale fluctuations in engine parameters and nonlinear deterministic coupling between successive engine cycles. Residual cylinder gas from each cycle alters the in-cylinder fuel-air ratio and thus the combustion efficiency in succeeding cycles. The model close-quote s simplicity allows rapid simulation of thousands of engine cycles, permitting statistical studies of cyclic-variation patterns and providing physical insight into this technologically important phenomenon. Using symbol statistics to characterize the noisy dynamics, we find good quantitative matches between our model and experimental time-series measurements. copyright 1998 The American Physical Society

40 CFR 60.4231 - What emission standards must I meet if I am a manufacturer of stationary SI internal combustion...

Science.gov (United States)

2010-07-01

... I am a manufacturer of stationary SI internal combustion engines or equipment containing such... Stationary Spark Ignition Internal Combustion Engines Emission Standards for Manufacturers § 60.4231 What emission standards must I meet if I am a manufacturer of stationary SI internal combustion engines or...

Experimental study of combustion and emission characteristics of ethanol fuelled port injected homogeneous charge compression ignition (HCCI) combustion engine

Energy Technology Data Exchange (ETDEWEB)

Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

2011-04-15

The homogeneous charge compression ignition (HCCI) is an alternative combustion concept for in reciprocating engines. The HCCI combustion engine offers significant benefits in terms of its high efficiency and ultra low emissions. In this investigation, port injection technique is used for preparing homogeneous charge. The combustion and emission characteristics of a HCCI engine fuelled with ethanol were investigated on a modified two-cylinder, four-stroke engine. The experiment is conducted with varying intake air temperature (120-150 C) and at different air-fuel ratios, for which stable HCCI combustion is achieved. In-cylinder pressure, heat release analysis and exhaust emission measurements were employed for combustion diagnostics. In this study, effect of intake air temperature on combustion parameters, thermal efficiency, combustion efficiency and emissions in HCCI combustion engine is analyzed and discussed in detail. The experimental results indicate that the air-fuel ratio and intake air temperature have significant effect on the maximum in-cylinder pressure and its position, gas exchange efficiency, thermal efficiency, combustion efficiency, maximum rate of pressure rise and the heat release rate. Results show that for all stable operation points, NO{sub x} emissions are lower than 10 ppm however HC and CO emissions are higher. (author)

Small Engine Repair. Two-Stroke and Four-Stroke Cycle.

Science.gov (United States)

Hires, Bill; And Others

This curriculum guide is intended to assist persons teaching a course in repairing two- and four-stroke cycle small engines. Addressed in the individual units of instruction are the following topics: safety, tools, fasteners, and measurement techniques; basic small engine theory (engine identification and inspection, basic engine principles and…

Relation of Hydrogen and Methane to Carbon Monoxide in Exhaust Gases from Internal-Combustion Engines

Science.gov (United States)

Gerrish, Harold C; Tessmann, Arthur M

1935-01-01

The relation of hydrogen and methane to carbon monoxide in the exhaust gases from internal-combustion engines operating on standard-grade aviation gasoline, fighting-grade aviation gasoline, hydrogenated safety fuel, laboratory diesel fuel, and auto diesel fuel was determined by analysis of the exhaust gases. Two liquid-cooled single-cylinder spark-ignition, one 9-cylinder radial air-cooled spark-ignition, and two liquid-cooled single-cylinder compression-ignition engines were used.

46 CFR 32.50-35 - Remote manual shutdown for internal combustion engine driven cargo pump on tank vessels-TB/ALL.

Science.gov (United States)

2010-10-01

... 46 Shipping 1 2010-10-01 2010-10-01 false Remote manual shutdown for internal combustion engine... for Cargo Handling § 32.50-35 Remote manual shutdown for internal combustion engine driven cargo pump on tank vessels—TB/ALL. (a) Any tank vessel which is equipped with an internal combustion engine...

Internal combustion engine for natural gas compressor operation

Energy Technology Data Exchange (ETDEWEB)

Hagen, Christopher L.; Babbitt, Guy; Turner, Christopher; Echter, Nick; Weyer-Geigel, Kristina

2016-04-19

This application concerns systems and methods for compressing natural gas with an internal combustion engine. In a representative embodiment, a system for compressing a gas comprises a reciprocating internal combustion engine including at least one piston-cylinder assembly comprising a piston configured to travel in a cylinder and to compress gas in the cylinder in multiple compression stages. The system can further comprise a first pressure tank in fluid communication with the piston-cylinder assembly to receive compressed gas from the piston-cylinder assembly until the first pressure tank reaches a predetermined pressure, and a second pressure tank in fluid communication with the piston-cylinder assembly and the first pressure tank. The second pressure tank can be configured to receive compressed gas from the piston-cylinder assembly until the second pressure tank reaches a predetermined pressure. When the first and second pressure tanks have reached the predetermined pressures, the first pressure tank can be configured to supply gas to the piston-cylinder assembly, and the piston can be configured to compress the gas supplied by the first pressure tank such that the compressed gas flows into the second pressure tank.

Results of measurements of emission from internal combustion engines

International Nuclear Information System (INIS)

Dimitrovski, Mile; Jovanovska, Vangelica

1999-01-01

A mathematical model for solving the emission from internal combustion engines on the cross roads are made. The exhausted pipes from vehicles are substituted with a pipe in a centre of the cross road. This model is proved with measurement made on vehicles in the city of Bitola (Macedonia). (Author)

Technology for emission control in internal combustion engines; Kakushu nainen kikan ni okeru hai gas joka gijutsu

Energy Technology Data Exchange (ETDEWEB)

Shioji, M. [Kyoto University, Kyoto (Japan)

1998-09-01

Described herein are emission control technology and exhaust gas cleaning measures for internal combustion engines. Gas turbines burn relatively high-quality fuels, such as natural gas, kerosene, diesel oil and gas oil, where the major concerns are to reduce NOx and dust emissions. The NOx abatement techniques fall into two general categories; wet processes which inject water or steam, and dry processes which depend on improved combustion. Power generation and cogeneration which burn natural gas adopt lean, premixed combustion and two-stage combustion as the major approaches. Low-speed, large-size diesel engines, which realize very high thermal efficiency, discharge high concentrations of NOx. Delayed fuel injection timing is the most easy NOx abatement technique to meet the related regulations, but is accompanied by decreased fuel economy. Use of water-emulsified fuel, water layer injection and multi-port injection can reduce NOx emissions without decreasing fuel economy, depending on optimization methods adopted. Automobile gasoline engines are required to further clean exhaust gases by catalystic systems. 9 refs., 10 figs., 6 tabs.

Control of internal combustion engines and hybrid engines; Regelung von Verbrennungsmotoren und Hybridantrieben

Energy Technology Data Exchange (ETDEWEB)

Isermann, R. [TU Darmstadt (Germany). Forschungsgruppe Regelungstechnik und Prozessautomatisierung

2007-07-15

In the development of internal combustion engines, there are increasingly rigid specifications for further reduction of consumption, exhaust and noise emissions, better specific performance, lower weight, and good driving characteristics. The contributions in this special issue provide an insight into the many aspects of internal combustion engine and hybrid engine control. The editors of at journal took care to select interesting papers presented at the 3. VDI/VDE-GMA conference AUTOREG 2006. They show how control and mechatronics support the high demands on functionality in motor car engineering. (orig.)

Fuels and Combustion

KAUST Repository

Johansson, Bengt

2016-08-17

This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

Fuels and Combustion

KAUST Repository

Johansson, Bengt

2016-01-01

This chapter discusses the combustion processes and the link to the fuel properties that are suitable for them. It describes the basic three concepts, including spark ignition (SI) and compression ignition (CI), and homogeneous charge compression ignition (HCCI). The fuel used in a CI engine is vastly different from that in an SI engine. In an SI engine, the fuel should sustain high pressure and temperature without autoignition. Apart from the dominating SI and CI engines, it is also possible to operate with a type of combustion: autoignition. With HCCI, the fuel and air are fully premixed before combustion as in the SI engine, but combustion is started by the increased pressure and temperature during the compression stroke. Apart from the three combustion processes, there are also a few combined or intermediate concepts, such as Spark-Assisted Compression Ignition (SACI). Those concepts are discussed in terms of the requirements of fuel properties.

Exhaust system of an internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

1974-09-04

A catalytic converter system for internal combustion engines is described that includes a means to maintain the catalyst temperature within a predetermined range for the efficient reduction of nitrogen oxides in the exhaust gas. Upstream of the catalytic converter, the exhaust pipe is encased in a structure such that a space is provided for the flow of a coolant around the exhaust pipe in response to the sensed catalytic temperature. A coolant control valve is actuated in response to the temperature sensor.

A sustained-arc ignition system for internal combustion engines

Science.gov (United States)

Birchenough, A. G.

1977-01-01

A sustained-arc ignition system was developed for internal combustion engines. It produces a very-long-duration ignition pulse with an energy in the order of 100 millijoules. The ignition pulse waveform can be controlled to predetermined actual ignition requirements. The design of the sustained-arc ignition system is presented in the report.

Secondary drive of an internal combustion engine for an air presser. Nebenantrieb einer Brennkraftmaschine fuer einen Luftpresser

Energy Technology Data Exchange (ETDEWEB)

Kubis, H.

1990-04-19

The invention concerns an air presser propelled by a gearwheel and designed as a piston compressor. The drive gearwheel on the air presser crankshaft meshes with a gearwheel on the camshaft of the internal combustion engine. In the case of these drives, a negative torque of the air presser results when the top dead centre of the air presser piston is reached. This is accompanied by an unpleasant noise. In addition, the driving torque of the camshaft often has negative fractions. If the negative torque of the air presser is superposed by small or negative torques of the camshaft in the re-expansion phase additionally to the air presser wheel there will be a backward acceleration of the camshaft gear which propagates as impact into the rest of the gear drive. The invention prevents the backward acceleration of the camshaft wheel and minimizes stroke momentum and noise in the mesh of the camshaft wheel.

Biogas utilization as flammable for internal combustion engine

International Nuclear Information System (INIS)

Cardenas, H.

1995-01-01

In this work the energetic potential stored in form of generated biogas of organic industrial wastes treatment is analyzed. Biogas utilization as flammable at internal combustion engine coupled to electrical energy generating is studied in the Wastewater Treatment Plant of Bucaramanga city (Colombia). This Plant was designed for 160.000 habitants treatment capacity, 1300 m3/h wealth, 170 BDO/m3 residues concentration and 87% process efficiency. The plant generate 2.000 m3/d of biogas. In laboratory trials was worked with biogas originating from Treatment Plant, both without purifying and purified, and the obtained results were compared with both yields determined with 86-octanes gasoline and natural gas. The analysis of pollutant by-products generated in combustion process as leak gases, present corrosive compounds and not desirable. elements in biogas composition are included

The thermodynamic characteristics of high efficiency, internal-combustion engines

International Nuclear Information System (INIS)

Caton, Jerald A.

2012-01-01

Highlights: ► The thermodynamics of an automotive engine are determined using a cycle simulation. ► The net indicated thermal efficiency increased from 37.0% to 53.9%. ► High compression ratio, lean mixtures and high EGR were the important features. ► Efficiency increased due to lower heat losses, and increased work conversion. ► The nitric oxides were essentially zero due to the low combustion temperatures. - Abstract: Recent advancements have demonstrated new combustion modes for internal combustion engines that exhibit low nitric oxide emissions and high thermal efficiencies. These new combustion modes involve various combinations of stratification, lean mixtures, high levels of EGR, multiple injections, variable valve timings, two fuels, and other such features. Although the exact combination of these features that provides the best design is not yet clear, the results (low emissions with high efficiencies) are of major interest. The current work is directed at determining some of the fundamental thermodynamic reasons for the relatively high efficiencies and to quantify these factors. Both the first and second laws are used in this assessment. An automotive engine (5.7 l) which included some of the features mentioned above (e.g., high compression ratios, lean mixtures, and high EGR) was evaluated using a thermodynamic cycle simulation. These features were examined for a moderate load (bmep = 900 kPa), moderate speed (2000 rpm) condition. By the use of lean operation, high EGR levels, high compression ratio and other features, the net indicated thermal efficiency increased from 37.0% to 53.9%. These increases are explained in a step-by-step fashion. The major reasons for these improvements include the higher compression ratio and the dilute charge (lean mixture, high EGR). The dilute charge resulted in lower temperatures which in turn resulted in lower heat loss. In addition, the lower temperatures resulted in higher ratios of the specific heats which

75 FR 80761 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2010-12-23

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 63 [EPA-HQ-OAR-2008-0708, FRL-9244-2] RIN 2060-AP36 National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines... combustion engines and requesting public comment on one issue arising from the final rule. Specifically, EPA...

Internal combustion engines in stationary installations for the efficient use of energy. VDI-meeting at Stuttart

Energy Technology Data Exchange (ETDEWEB)

Titl, A

1976-11-01

The efficient use of stationary internal combustion engines for energy supply is discussed: the state of technology and the scientific significance of internal combustion engines; thermal power coupling with unit-type thermal power plants which supply current as well as heat; and operational experience with unit-type thermal power plants for living districts, sport centers, industries etc.

Hydrogen enriched compressed natural gas (HCNG: A futuristic fuel for internal combustion engines

Directory of Open Access Journals (Sweden)

Nanthagopal Kasianantham

2011-01-01

Full Text Available Air pollution is fast becoming a serious global problem with increasing population and its subsequent demands. This has resulted in increased usage of hydrogen as fuel for internal combustion engines. Hydrogen resources are vast and it is considered as one of the most promising fuel for automotive sector. As the required hydrogen infrastructure and refueling stations are not meeting the demand, widespread introduction of hydrogen vehicles is not possible in the near future. One of the solutions for this hurdle is to blend hydrogen with methane. Such types of blends take benefit of the unique combustion properties of hydrogen and at the same time reduce the demand for pure hydrogen. Enriching natural gas with hydrogen could be a potential alternative to common hydrocarbon fuels for internal combustion engine applications. Many researchers are working on this for the last few years and work is now focused on how to use this kind of fuel to its maximum extent. This technical note is an assessment of HCNG usage in case of internal combustion engines. Several examples and their salient features have been discussed. Finally, overall effects of hydrogen addition on an engine fueled with HCNG under various conditions are illustrated. In addition, the scope and challenges being faced in this area of research are clearly described.

Proceedings of the sixth international conference on fluidized bed combustion. Volume III. Technical sessions

Energy Technology Data Exchange (ETDEWEB)

None

1980-08-01

The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. Forty-five papers from Vol. III of the proceedings have been entered individually into EDB and ERA. Two papers had been entered previously from other sources. (LTN)

Two Strokes Diesel Engine - Promising Solution to Reduce CO2 Emissions

OpenAIRE

Tribotte, Pascal; Ravet, Frederic; Dugue, Vincent; Obernesser, Philippe; Quechon, Nicolas; Benajes, Jesus; Novella, Ricardo; De Lima, Daniela

2012-01-01

Two-stroke engines have dropped out of the automobile market for a long time due to severe drawbacks. Unfortunately, the comparison with the performances of four-stroke engines was not in favour of two-stroke ones. Nevertheless, the needs of a more compact engine with a better ratio of the mass and size versus power motivated research efforts at the beginning of the 90's. Regrettably, these efforts did not result in commercial success and automobile manufacturers kept four-stroke engine archi...

Optimizing the Performance of a 50cc Compression Ignition Two-Stroke Engine Operating on Dimethyl Ether

DEFF Research Database (Denmark)

Hansen, Kim Rene; Dolriis, J.D.; Hansson, C.

2011-01-01

The paper describes the optimization of a 50cc crankcase scavenged two-stroke diesel engine operating on dimethyl ether (DME). The optimization is primarily done with respect to engine efficiency. The underlying idea behind the work is that the low weight, low internal friction and low engine...

Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms

CERN Document Server

Williams, J J

2013-01-01

Modern design methods of Automotive Cam Design require the computation of a range of parameters. This book provides a logical sequence of steps for the derivation of the relevant equations from first principles, for the more widely used cam mechanisms. Although originally derived for use in high performance engines, this work is equally applicable to the design of mass produced automotive and other internal combustion engines.   Introduction to Analytical Methods for Internal Combustion Engine Cam Mechanisms provides the equations necessary for the design of cam lift curves with an associated smooth acceleration curve. The equations are derived for the kinematics and kinetics of all the mechanisms considered, together with those for cam curvature and oil entrainment velocity. This permits the cam shape, all loads, and contact stresses to be evaluated, and the relevant tribology to be assessed. The effects of asymmetry on the manufacture of cams for finger follower and offset translating curved followers is ...

Fuel injection system for internal combustion engines. Kraftstoffeinspritzsystem fuer Brennkraftmaschinen

Energy Technology Data Exchange (ETDEWEB)

Hafner, U.

1990-09-13

A fuel injection system for an internal combustion engine is provided with a fuel supply line (13) and at least one electromagnetically actuated fuel injection valve (14) for apportioning a quantity of fuel for injection. A connection muzzle (24) coming from the valve body (23) juts into an opening (22) in the suction pipe (21) of the internal combustion engine. The end of the injection valve opposite the connecting muzzle (24) is connected with the fuel supply line via a fuel entry. The valve body (23) is enclosed by a casing (25) in order to provide the conditions required for a warm start. An annulus (31) extending over a large part of the axial length of the valve remains between the casing and the valve body (23). The annulus (31) communicates with the fuel flow through the fuel supply line (13) via an afflux and an efflux opening (32, 33) (Fig. 1).

Fuel injection apparatus for internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Fujisawa, H; Kobayashi, H; Nagata, S

1975-01-07

A fuel injection apparatus for a rapid cut of fuel supply to internal combustion engines during deceleration is described. The fuel cut is achieved by an electromagnetic switch. The number of engine revolutions are determined by the movement of cam shafts, and one of the cam shafts is made of electroconductive and nonconductive materials which generate an intermittent electrical signal to the magnetic switch. The device can cut the fuel in any deceleration condition, therefore it is more advantageous than fuel injection utilizing the intake load variation which can operate only under certain deceleration conditions.

Research Needs and Impacts in Predictive Simulation for Internal Combustion Engines (PreSICE)

Energy Technology Data Exchange (ETDEWEB)

Eckerle, Wayne [Cummins, Inc., Columbus, IN (United States); Rutland, Chris [Univ. of Wisconsin, Madison, WI (United States); Rohlfing, Eric [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Singh, Gurpreet [Dept. of Energy (DOE), Washington DC (United States). Office of Energy Efficiency and Renewable Energy; McIlroy, Andrew [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2011-03-03

This report is based on a SC/EERE Workshop to Identify Research Needs and Impacts in Predictive Simulation for Internal Combustion Engines (PreSICE), held March 3, 2011, to determine strategic focus areas that will accelerate innovation in engine design to meet national goals in transportation efficiency. The U.S. has reached a pivotal moment when pressures of energy security, climate change, and economic competitiveness converge. Oil prices remain volatile and have exceeded $100 per barrel twice in five years. At these prices, the U.S. spends $1 billion per day on imported oil to meet our energy demands. Because the transportation sector accounts for two-thirds of our petroleum use, energy security is deeply entangled with our transportation needs. At the same time, transportation produces one-quarter of the nation’s carbon dioxide output. Increasing the efficiency of internal combustion engines is a technologically proven and cost-effective approach to dramatically improving the fuel economy of the nation’s fleet of vehicles in the near- to mid-term, with the corresponding benefits of reducing our dependence on foreign oil and reducing carbon emissions. Because of their relatively low cost, high performance, and ability to utilize renewable fuels, internal combustion engines—including those in hybrid vehicles—will continue to be critical to our transportation infrastructure for decades. Achievable advances in engine technology can improve the fuel economy of automobiles by over 50% and trucks by over 30%. Achieving these goals will require the transportation sector to compress its product development cycle for cleaner, more efficient engine technologies by 50% while simultaneously exploring innovative design space. Concurrently, fuels will also be evolving, adding another layer of complexity and further highlighting the need for efficient product development cycles. Current design processes, using “build and test” prototype engineering, will not

Brayton cycle for internal combustion engine exhaust gas waste heat recovery

Directory of Open Access Journals (Sweden)

J Galindo

2015-06-01

Full Text Available An average passenger car engine effectively uses about one-third of the fuel combustion energy, while the two-thirds are wasted through exhaust gases and engine cooling. It is of great interest to automotive industry to recover some of this wasted energy, thus increasing the engine efficiency and lowering fuel consumption and contamination. Waste heat recovery for internal combustion engine exhaust gases using Brayton cycle machine was investigated. The principle problems of application of such a system in a passenger car were considered: compressor and expander machine selection, machine size for packaging under the hood, efficiency of the cycle, and improvement of engine efficiency. Important parameters of machines design have been determined and analyzed. An average 2-L turbocharged gasoline engine’s New European Driving Cycle points were taken as inlet points for waste heat recovery system. It is theoretically estimated that the recuperated power of 1515 W can be achieved along with 5.7% improvement in engine efficiency, at the point where engine power is 26550 W.

Holographic aids for internal combustion engine flow studies

Science.gov (United States)

Regan, C.

1984-01-01

Worldwide interest in improving the fuel efficiency of internal combustion (I.C.) engines has sparked research efforts designed to learn more about the flow processes of these engines. The flow fields must be understood prior to fuel injection in order to design efficient valves, piston geometries, and fuel injectors. Knowledge of the flow field is also necessary to determine the heat transfer to combustion chamber surfaces. Computational codes can predict velocity and turbulence patterns, but experimental verification is mandatory to justify their basic assumptions. Due to their nonintrusive nature, optical methods are ideally suited to provide the necessary velocity verification data. Optical sytems such as Schlieren photography, laser velocimetry, and illuminated particle visualization are used in I.C. engines, and now their versatility is improved by employing holography. These holographically enhanced optical techniques are described with emphasis on their applications in I.C. engines.

Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

Science.gov (United States)

Douvartzides, S.; Karmalis, I.

2016-11-01

Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

Ionization in the Knock Zone of an Internal-combustion Engine

Science.gov (United States)

Hasting, Charles E

1940-01-01

The ionization in the knock zone of an internal-combustion engine was investigated. A suspected correlation between the intensity of knock and the degree of ionization was verified and an oscillation in the degree of ionization corresponding in frequency to the knock vibrations in the cylinder pressure was observed.

Determination of TDC in internal combustion engines by a newly developed thermodynamic approach

International Nuclear Information System (INIS)

Pipitone, Emiliano; Beccari, Alberto

2010-01-01

In-cylinder pressure analysis is nowadays an indispensable tool in internal combustion engine research and development. It allows the measure of some important performance related parameters, such as indicated mean effective pressure (IMEP), mean friction pressure, indicated fuel consumption, heat release rate, mass fraction burned, etc. Moreover, future automotive engine will probably be equipped with in-cylinder pressure sensors for continuous combustion monitoring and control, in order to fulfil the more and more strict emission limits. For these reasons, in-cylinder pressure analysis must be carried out with maximum accuracy, in order to minimize the effects of its characteristic measurement errors. The exact determination of crank position when the piston is at top dead centre (TDC) is of vital importance, since a 1 deg. error can cause up to a 10% evaluation error on IMEP and 25% error on the heat released by the combustion: the position of the crank shaft (and hence the volume inside the cylinder) should be known with the precision of at least 0.1 crank angle degrees, which is not an easy task, even if the engine dimensions are well known: it corresponds to a piston movement in the order of one tenth of micron, which is very difficult to estimate. A good determination of the TDC position can be pursued by means of a dedicated capacitive TDC sensor, which allows a dynamic measurement (i.e. while engine is running) within the required 0.1 deg. precision . Such a sensor has a substantial cost and its use is not really fast, since it must be fitted in the spark plug or injector hole of the cylinder. A different approach can be followed using a thermodynamic method, whose input is in-cylinder pressure sampled during the compression and expansion strokes: some of these methods, more or less valid, can be found in literature . This paper will discuss a new thermodynamic approach to the problem of the right determination of the TDC position. The base theory of the

Multiple fuel supply system for an internal combustion engine

Science.gov (United States)

Crothers, William T.

1977-01-01

A multiple fuel supply or an internal combustion engine wherein phase separation of components is deliberately induced. The resulting separation permits the use of a single fuel tank to supply components of either or both phases to the engine. Specifically, phase separation of a gasoline/methanol blend is induced by the addition of a minor amount of water sufficient to guarantee separation into an upper gasoline phase and a lower methanol/water phase. A single fuel tank holds the two-phase liquid with separate fuel pickups and separate level indicators for each phase. Either gasoline or methanol, or both, can be supplied to the engine as required by predetermined parameters. A fuel supply system for a phase-separated multiple fuel supply contained in a single fuel tank is described.

Biomass downdraft gasifier with internal cyclonic combustion chamber: design, construction, and experimental results.

Science.gov (United States)

Patil, Krushna; Bhoi, Prakash; Huhnke, Raymond; Bellmer, Danielle

2011-05-01

An exploratory downdraft gasifier design with unique biomass pyrolysis and tar cracking mechanism is evolved at Oklahoma State University. This design has an internal separate combustion section where turbulent, swirling high-temperature combustion flows are generated. A series of research trials were conducted using wood shavings as the gasifier feedstock. Maximum tar cracking temperatures were above 1100°C. Average volumetric concentration levels of major combustible components in the product gas were 22% CO and 11% H(2). Hot and cold gas efficiencies were 72% and 66%, respectively. Copyright © 2011 Elsevier Ltd. All rights reserved.

Combustion of Liquid Bio-Fuels in an Internal Circulating Fluidized Bed

Czech Academy of Sciences Publication Activity Database

Miccio, F.; Kalisz, S.; Baxter, D.; Svoboda, Karel

2008-01-01

Roč. 143, 1-3 (2008), s. 172-179 ISSN 1385-8947 Institutional research plan: CEZ:AV0Z40720504 Keywords : internal circulating fluidized bed * liquid fuel * combustion Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.813, year: 2008

Experimental study of hydrogen as a fuel additive in internal combustion engines

Energy Technology Data Exchange (ETDEWEB)

Saanum, Inge

2008-07-01

Combustion of hydrocarbons in internal combustion engines results in emissions that can be harmful both to human health and to the environment. Although the engine technology is improving, the emissions of NO{sub x}, PM and UHC are still challenging. Besides, the overall consumption of fossil fuel and hence the emissions of CO{sub 2} are increasing because of the increasing number of vehicles. This has lead to a focus on finding alternative fuels and alternative technologies that may result in lower emissions of harmful gases and lower CO{sub 2} emissions. This thesis treats various topics that are relevant when using blends of fuels in different internal combustion engine technologies, with a particular focus on using hydrogen as a fuel additive. The topics addressed are especially the ones that impact the environment, such as emissions of harmful gases and thermal efficiency (fuel consumption). The thesis is based on experimental work performed at four different test rigs: 1. A dynamic combustion rig with optical access to the combustion chamber where spark ignited premixed combustion could be studied by means of a Schlieren optical setup and a high speed video camera. 2. A spark ignition natural gas engine rig with an optional exhaust gas recycling system. 3. A 1-cylinder diesel engine prepared for homogeneous charge compression ignition combustion. 4. A 6-cylinder standard diesel engine The engine rigs were equipped with cylinder pressure sensors, engine dynamometers, exhaust gas analyzers etc. to enable analyses of the effects of different fuels. The effect of hydrogen blended with methane and natural gas in spark ignited premixed combustion was investigated in the dynamic combustion rig and in a natural gas engine. In the dynamic combustion rig, the effect of hydrogen added to methane on the flame speed and the flame structure was investigated at elevated pressure and temperature. A considerable increase in the flame speed was observed when adding 30 vol

Development and Experimental Investigation of a Two-Stroke Opposed-Piston Free-Piston Engine

OpenAIRE

Schneider, Stephan; Chiodi, Marco; Friedrich, Horst E.; Bargende, Michael

2016-01-01

The proposed paper deals with the development process and initial measurement results of an opposed-piston combustion engine for application in a Free-Piston Linear Generator (FPLG). The FPLG, which is being developed at the German Aerospace Center (DLR), is an innovative internal combustion engine for a fuel based electrical power supply. With its arrangement, the pistons freely oscillate between the compression chamber of the combustion unit and a gas spring with no mechanical coupling like...

Path planning during combustion mode switch

Science.gov (United States)

Jiang, Li; Ravi, Nikhil

2015-12-29

Systems and methods are provided for transitioning between a first combustion mode and a second combustion mode in an internal combustion engine. A current operating point of the engine is identified and a target operating point for the internal combustion engine in the second combustion mode is also determined. A predefined optimized transition operating point is selected from memory. While operating in the first combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion engine to approach the selected optimized transition operating point. When the engine is operating at the selected optimized transition operating point, the combustion mode is switched from the first combustion mode to the second combustion mode. While operating in the second combustion mode, one or more engine actuator settings are adjusted to cause the operating point of the internal combustion to approach the target operating point.

International evaluation of the programme on fluid bed combustion and gasification

Energy Technology Data Exchange (ETDEWEB)

Kremer, H. [Ruhr Univ., Bochum (Germany); Magnusson, B.F. [Norwegian Univ. of Science and Technology, Trondheim (Norway); Reed, T. [Colorado School of Mines (United States)

1996-12-31

This report on the Swedish National Program on Fluid Bed Combustion and Gasification is part of the on-going evaluation process adopted by the funding organization NUTEK. This agency has invited the undersigned to act as members of an international panel responsible for evaluating the progress made in 9 projects initiated between 1993-1996. The output of this evaluation procedure is given in this report. The main aim of the Fluid Bed Combustion and Gasification Program is to develop industrially relevant knowledge and competence in experimental and computational techniques capable of characterizing the flow, heat transfer, combustion, gasification, ash formation and deposition and emissions in fluid bed gasifiers and combustors. To achieve this aim NUTEK is sponsoring research in a number of universities and encourages close cooperation between universities and industry. In the evaluation of the various sponsored research programs, the evaluation committee has considered the following key points: relevance of research to industrial needs; originality of research; program management; adequacy of resources; degree of collaboration between industry and academia; international standing of research. In this report comments and recommendations are made on individual projects as well as on the programme in general and they express the unanimous view of the panel members

International evaluation of the programme on fluid bed combustion and gasification

Energy Technology Data Exchange (ETDEWEB)

Kremer, H [Ruhr Univ., Bochum (Germany); Magnusson, B F [Norwegian Univ. of Science and Technology, Trondheim (Norway); Reed, T [Colorado School of Mines (United States)

1997-12-31

This report on the Swedish National Program on Fluid Bed Combustion and Gasification is part of the on-going evaluation process adopted by the funding organization NUTEK. This agency has invited the undersigned to act as members of an international panel responsible for evaluating the progress made in 9 projects initiated between 1993-1996. The output of this evaluation procedure is given in this report. The main aim of the Fluid Bed Combustion and Gasification Program is to develop industrially relevant knowledge and competence in experimental and computational techniques capable of characterizing the flow, heat transfer, combustion, gasification, ash formation and deposition and emissions in fluid bed gasifiers and combustors. To achieve this aim NUTEK is sponsoring research in a number of universities and encourages close cooperation between universities and industry. In the evaluation of the various sponsored research programs, the evaluation committee has considered the following key points: relevance of research to industrial needs; originality of research; program management; adequacy of resources; degree of collaboration between industry and academia; international standing of research. In this report comments and recommendations are made on individual projects as well as on the programme in general and they express the unanimous view of the panel members

Numerical Modelling of the Operation of a Novel Two Stroke V4 Engine

Directory of Open Access Journals (Sweden)

Albert Boretti

2017-02-01

Full Text Available The paper presents simulations of the operation of a novel two-stroke engine for road Super Sport motorcycles. Two-stroke engines were preferred to four-stroke engines in Grand Prix motorcycle racing until the start of the Moto GP era when new rules phased out the two-stroke engines. Reasons for the change were the poor fuel economy and significant pollutant emissions. The paper discusses the opportunity of a came back at least in road Super Sport motorcycles thanks to the recent advantages in direct injection and precise lubrication for two-stroke engines, plus the opportunity to use jet ignition, based on performance simulations.

40 CFR 60.4203 - How long must my engines meet the emission standards if I am a stationary CI internal combustion...

Science.gov (United States)

2010-07-01

... emission standards if I am a stationary CI internal combustion engine manufacturer? 60.4203 Section 60.4203... Combustion Engines Emission Standards for Manufacturers § 60.4203 How long must my engines meet the emission standards if I am a stationary CI internal combustion engine manufacturer? Engines manufactured by...

Concept for lowest emissions of a hydrogen internal combustion engine; Niedrigstemissionskonzept fuer einen wasserstoffbetriebenen Verbrennungsmotor

Energy Technology Data Exchange (ETDEWEB)

Fouquet, Marcel Christian Thomas

2012-03-15

This paper describes a concept with lowest emissions for a hydrogen internal combustion engine for passenger cars. With optimisation of the combustion concept the level of nitrogen oxide is below 90%, hydrocarbon and carbon monoxide below 99% of the SULEV target (CARB). This concept enables a potential in power density that is comparable to current supercharged combustion engines at lowest emission level without catalytic aftertreatment. Additionally with a catalytic aftertreatment system, the emission level of a current hydrogen combustion engine (mono-fuel) is lowered to a level, that this car can be labeled as air cleaning vehicle for hydrocarbons and carbon monoxide.

Measurement and Calculation of Frictional Loss in Large Two-Stroke Engines

DEFF Research Database (Denmark)

Vølund, Anders

2003-01-01

The total frictional loss in a large two-stroke marine diesel engine is rather well determined. However, the contribution (size and distribution) from the different machine elements are not well known. The aim of this study is to establish methods to measure and calculate friction in the piston...... assembly and guide shoe system for a large two-stroke marine diesel engine. These components are the two major contributors to the total friction in a two-stroke marine diesel engine. The piston pack represents approximately 60% of the total mechanical loss at full load and the guide shoe system 23...

Impact of Fuel Type on the Internal Combustion Engine Condition

Directory of Open Access Journals (Sweden)

Zdravko Schauperl

2012-07-01

Full Text Available The paper studies the influence of liquefied petroleum gas as alternative fuel on the condition of the internal combustion engine. The traffic, energy, economic and ecological influence as well as the types of fuel are studied and analyzed in an unbiased manner, objectively, and in detail, and the obtained results are compared with the condition of the engine of a vehicle powered by the stipulated fuel, petrol Eurosuper 95. The study was carried out on two identical passenger cars with one being fitted with gas installation. The obtained results show that properly installed gas installations in vehicles and the usage of LPG have no significant influence on the driving performances, but they affect significantly the ecological and economic parameters of using passenger cars.

Numerical investigation of soot formation and oxidation processes under large two-stroke marine diesel engine-like conditions using integrated CFD-chemical kinetics

DEFF Research Database (Denmark)

Pang, Kar Mun; Karvounis, Nikolas; Walther, Jens Honore

2016-01-01

n-heptane mechanism and a revised multi-step soot model using laser extinction measurements of diesel soot obtained at different ambient pressure levels in an optical accessible, constant volume chamber experiment. It is revealed that ignition delay times and liftoff lengths generated using the new......In this reported work, multi-dimensional computational fluid dynamics studies of diesel combustion and soot formation processes in a constant volume combustion chamber and a marine diesel engine are carried out. The key interest here is firstly to validate the coupling of a newly developed skeletal...... using the revised soot model agrees reasonably well with the measurements in terms of peak values. The numerical model is subsequently applied to investigate the flame development, soot/nitrogen monoxide formation and heat transfer in a two-stroke, low-speed uniflow-scavenged marine diesel engine...

Burden of stroke in Bangladesh.

Science.gov (United States)

Islam, Md Nazmul; Moniruzzaman, Mohammed; Khalil, Md Ibrahim; Basri, Rehana; Alam, Mohammad Khursheed; Loo, Keat Wei; Gan, Siew Hua

2013-04-01

Stroke is the third leading cause of death in Bangladesh. The World Health Organization ranks Bangladesh's mortality rate due to stroke as number 84 in the world. The reported prevalence of stroke in Bangladesh is 0.3%, although no data on stroke incidence have been recorded. Hospital-based studies conducted in past decades have indicated that hypertension is the main cause of ischaemic and haemorrhagic stroke in Bangladesh. The high number of disability-adjusted life-years lost due to stroke (485 per 10,000 people) show that stroke severely impacts Bangladesh's economy. Although two non-governmental organizations, BRAC and the Centre for the Rehabilitation of the Paralysed, are actively involved in primary stroke prevention strategies, the Bangladeshi government needs to emphasize healthcare development to cope with the increasing population density and to reduce stroke occurrence. © 2012 The Authors. International Journal of Stroke © 2012 World Stroke Organization.

Combustion characteristics of lemongrass (Cymbopogon flexuosus oil in a partial premixed charge compression ignition engine

Directory of Open Access Journals (Sweden)

Avinash Alagumalai

2015-09-01

Full Text Available Indeed, the development of alternate fuels for use in internal combustion engines has traditionally been an evolutionary process in which fuel-related problems are met and critical fuel properties are identified and their specific limits defined to resolve the problem. In this regard, this research outlines a vision of lemongrass oil combustion characteristics. In a nut-shell, the combustion phenomena of lemongrass oil were investigated at engine speed of 1500 rpm and compression ratio of 17.5 in a 4-stroke cycle compression ignition engine. Furthermore, the engine tests were conducted with partial premixed charge compression ignition-direct injection (PCCI-DI dual fuel system to profoundly address the combustion phenomena. Analysis of cylinder pressure data and heat-release analysis of neat and premixed lemongrass oil were demonstrated in-detail and compared with conventional diesel. The experimental outcomes disclosed that successful ignition and energy release trends can be obtained from a compression ignition engine fueled with lemongrass oil.

A quick, simplified approach to the evaluation of combustion rate from an internal combustion engine indicator diagram

Directory of Open Access Journals (Sweden)

Tomić Miroljub V.

2008-01-01

Full Text Available In this paper a simplified procedure of an internal combustion engine in-cylinder pressure record analysis has been presented. The method is very easy for programming and provides quick evaluation of the gas temperature and the rate of combustion. It is based on the consideration proposed by Hohenberg and Killman, but enhances the approach by involving the rate of heat transferred to the walls that was omitted in the original approach. It enables the evaluation of the complete rate of heat released by combustion (often designated as “gross heat release rate” or “fuel chemical energy release rate”, not only the rate of heat transferred to the gas (which is often designated as “net heat release rate”. The accuracy of the method has been also analyzed and it is shown that the errors caused by the simplifications in the model are very small, particularly if the crank angle step is also small. A several practical applications on recorded pressure diagrams taken from both spark ignition and compression ignition engine are presented as well.

Thermal Loss Determination for a Small Internal Combustion Engine

Science.gov (United States)

2014-03-27

an engine driven compressor (supercharger) or by means of an exhaust turbine driven compressor (turbocharger). The compressed air has a higher density...low and high adjustment screws were screwed in (leaned) or out (enrich) as needed to bring the air /fuel mixture closer to stoichiometric conditions...THERMAL LOSS DETERMINATION FOR A SMALL INTERNAL COMBUSTION ENGINE THESIS Joshua A. Rittenhouse, Captain, USAF AFIT-ENY-14-M-41 DEPARTMENT OF THE AIR

Starting apparatus for internal combustion engines

Science.gov (United States)

Dyches, Gregory M.; Dudar, Aed M.

1997-01-01

An internal combustion engine starting apparatus uses a signal from a curt sensor to determine when the engine is energized and the starter motor should be de-energized. One embodiment comprises a transmitter, receiver, computer processing unit, current sensor and relays to energize a starter motor and subsequently de-energize the same when the engine is running. Another embodiment comprises a switch, current transducer, low-pass filter, gain/comparator, relay and a plurality of switches to energize and de-energize a starter motor. Both embodiments contain an indicator lamp or speaker which alerts an operator as to whether a successful engine start has been achieved. Both embodiments also contain circuitry to protect the starter and to de-energize the engine.

Convex modeling and sizing of electrically supercharged internal combustion engine powertrain

NARCIS (Netherlands)

Marinkov, S.; Murgovski, N.; de Jager, B.

2016-01-01

This paper investigates a concept of an electrically supercharged internal combustion engine powertrain. A supercharger consists of an electric motor and a compressor. It draws its power from an electric energy buffer (e.g., a battery) and helps the engine during short-duration high-power demands.

Traveling-Wave Thermoacoustic Engines With Internal Combustion

Science.gov (United States)

Weiland, Nathan Thomas; Zinn, Ben T.; Swift, Gregory William

2004-05-11

Thermoacoustic devices are disclosed wherein, for some embodiments, a combustion zone provides heat to a regenerator using a mean flow of compressible fluid. In other embodiments, burning of a combustible mixture within the combustion zone is pulsed in phase with the acoustic pressure oscillations to increase acoustic power output. In an example embodiment, the combustion zone and the regenerator are thermally insulated from other components within the thermoacoustic device.

Exhaust emissions of low level blend alcohol fuels from two-stroke and four-stroke marine engines

Science.gov (United States)

Sevik, James M., Jr.

The U.S. Renewable Fuel Standard mandates that by 2022, 36 billion gallons of renewable fuels must be produced on a yearly basis. Ethanol production is capped at 15 billion gallons, meaning 21 billion gallons must come from different alternative fuel sources. A viable alternative to reach the remainder of this mandate is iso-butanol. Unlike ethanol, iso-butanol does not phase separate when mixed with water, meaning it can be transported using traditional pipeline methods. Iso-butanol also has a lower oxygen content by mass, meaning it can displace more petroleum while maintaining the same oxygen concentration in the fuel blend. This research focused on studying the effects of low level alcohol fuels on marine engine emissions to assess the possibility of using iso-butanol as a replacement for ethanol. Three marine engines were used in this study, representing a wide range of what is currently in service in the United States. Two four-stroke engine and one two-stroke engine powered boats were tested in the tributaries of the Chesapeake Bay, near Annapolis, Maryland over the course of two rounds of weeklong testing in May and September. The engines were tested using a standard test cycle and emissions were sampled using constant volume sampling techniques. Specific emissions for two-stroke and four-stroke engines were compared to the baseline indolene tests. Because of the nature of the field testing, limited engine parameters were recorded. Therefore, the engine parameters analyzed aside from emissions were the operating relative air-to-fuel ratio and engine speed. Emissions trends from the baseline test to each alcohol fuel for the four-stroke engines were consistent, when analyzing a single round of testing. The same trends were not consistent when comparing separate rounds because of uncontrolled weather conditions and because the four-stroke engines operate without fuel control feedback during full load conditions. Emissions trends from the baseline test to each

Bearings for high performance requirements in two-stroke and four-stroke diesel engines

Energy Technology Data Exchange (ETDEWEB)

Ederer, U.G.

1983-11-01

Most measures to reduce fuel consumption in diesel engines lead, directly or indirectly, to more severe operating conditions for the engine bearings. In ever more instances the bearings become the components which limit useful engine life and the time between overhauls. Bearings with improved performance characteristics are required. During recent years, Miba Gleitlager AG has developed several solutions to meet these requirements. They consist of either material improvements, such as a cast white metal (SnSb 12Cu 3 NiCd) with higher fatigue strength, or an electroplated overlay (PbSn 18 Cu) with improved fatigue and wear resistance. New design solutions found included the steel-Al Sn 6-WM 85 bearing for two-stroke engines, the steel-Al Sn 6 PbSn 18 Cu bearing applied to two-stroke crosshead bearings, the steel-AlZn 4,5 PbSn 18 Cu bearing for high bearing loads in four-stroke engines, and the Miba-Rillenlager with its radically new running-surface structure for extreme load and wear conditions. The application potential of these bearings and the operating experience with them are discussed in this article.

Simulation investigation of flow field inside the rotary engine : during intake and compression stroke

Energy Technology Data Exchange (ETDEWEB)

Poojitganont, T.; Berg, H.P.; Izweik, H.T. [Brandenburg Univ. of Technology Cottbus, Cottbus (Germany)

2009-07-01

As a result of continuously increasing oil prices, automotive industries are looking for alternative power sources for their automobiles. An excellent solution is the hybrid system. However due to the additional weight of its batteries, this causes the total weight of the car to increase. This higher battery weight can be compensated by reducing the weight of the engine. A rotary engine, such as the Wankel rotary engine, has a more attractive power to weight ratio than the normal reciprocating engine. The rotary engine can be treated and evaluated with respect to performance characteristics as a displacement type, four-stroke internal combustion engine, one-cycle similar to the reciprocating engine. For any combustion engine to reach the maximum power output, the mixture formation inside the engine should be considered. The flow phenomenon inside the engine is a key parameter which involves the mixture formation mechanism. This paper investigated the spray characteristic from the injector and the flow phenomena inside the combustion chamber. Its behaviours were studied using computational fluid dynamics simulation. The simulation setup was described in detail, with reference to meshes; initial condition; and boundary condition. Verification of the calculation was also presented. A comparison of the temperature during compression stroke from the analytical calculation and the adiabetic system simulation were also illustrated. Simulation results showed that the speed of the engine provides a proportional effect on the magnitude of air velocity inside the engine, whereas the circulation region can be expanded by increasing the intake pressure during the intake stroke. 9 refs., 1 tab., 13 figs.

Numerical Modelling of the Operation of a Novel Two Stroke V4 Engine

OpenAIRE

Albert Boretti

2017-01-01

The paper presents simulations of the operation of a novel two-stroke engine for road Super Sport motorcycles. Two-stroke engines were preferred to four-stroke engines in Grand Prix motorcycle racing until the start of the Moto GP era when new rules phased out the two-stroke engines. Reasons for the change were the poor fuel economy and significant pollutant emissions. The paper discusses the opportunity of a came back at least in road Super Sport motorcycles thanks to the recent advantages i...

Quality of stroke care at an Irish Regional General Hospital and Stroke Rehabilitation Unit.

LENUS (Irish Health Repository)

Walsh, T

2012-01-31

BACKGROUND: Robust international data support the effectiveness of stroke unit (SU) care. Despite this, most stroke care in Ireland are provided outside of this setting. Limited data currently exist on the quality of care provided. AIM: The aim of this study is to examine the quality of care for patients with stroke in two care settings-Regional General Hospital (RGH) and Stroke Rehabilitation Unit (SRU). METHODS: A retrospective analysis of the stroke records of consecutive patients admitted to the SRU between May-November 2002 and April-November 2004 was performed applying the UK National Sentinel Audit of Stroke (NSAS) tool. RESULTS: The results of the study reveal that while SRU processes of care was 74% compliant with standards; compliance with stroke service organisational standards was only 15 and 43% in the RGH and SRU, respectively. CONCLUSION: The quality of stroke care in our area is deficient. Comprehensive reorganisation of stroke services is imperative.

ACUTE BEHAVORIAL EFFECTS FROM EXPOSURE TO TWO-STROKE ENGINE EXHAUST

Science.gov (United States)

Benefits of changing from two-stroke to four-stroke engines (and other remedial requirements) can be evaluated (monetized) from the standpoint of acute behavioral effects of human exposure to exhaust from these engines. The monetization process depends upon estimates of the magn...

Cylinder head seal for piston engines especially internal combustion engines. Zylinderkopfdichtung fuer Hubkolbenmaschinen, insbesondere Brennkraftmaschinen

Energy Technology Data Exchange (ETDEWEB)

Kubis, H.; Winter, J.

1991-01-17

The invention concerns a cylinder head seal for reciprocating piston engines especially internal combustion engines and preferentially those with cylinder sleeves. With performances of internal combustion engines encreasing all the time it is becoming more and more difficult to seal the cylinder heat. The invention proposes a ring seal whose sides are plastically deformed when the cylinder headed screws are tightened. The inner deformations of the cylinder head resulting from the pressure forces inside the cylinder are compensated by means of elastic spring action of the combustion chamber sealing ring. The dimension of land, groove and sides are matched in such a way as to prevent any seal squeezing during plastification which would result in a deformation of the cylinder sleeve. The ring can therefore be set directly into the centering of the cylinder sleeve. Separate centering devices are not required.

29 CFR 1915.136 - Internal combustion engines, other than ship's equipment.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Internal combustion engines, other than ship's equipment. 1915.136 Section 1915.136 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Tools and Related Equipment §...

Combustion characteristics and influential factors of isooctane active-thermal atmosphere combustion assisted by two-stage reaction of n-heptane

Energy Technology Data Exchange (ETDEWEB)

Lu, Xingcai; Ji, Libin; Ma, Junjun; Zhou, Xiaoxin; Huang, Zhen [Key Lab. for Power Machinery and Engineering of MOE, Shanghai Jiao Tong University, 200240 Shanghai (China)

2011-02-15

This paper presents an experimental study on the isooctane active-thermal atmosphere combustion (ATAC) which is assisted by two-stage reaction of n-heptane. The active-thermal atmosphere is created by low- and high-temperature reactions of n-heptane which is injected at intake port, and isooctane is directly injected into combustion chamber near the top dead center. The effects of isooctane injection timing, active-thermal atmosphere intensity, overall equivalence ratio, and premixed ratio on combustion characteristics and emissions are investigated. The experimental results reveal that, the isooctane ignition and combustion can be classified to thermal atmosphere combustion, active atmosphere combustion, and active-thermal atmosphere combustion respectively according to the extent of n-heptane oxidation as well as effects of isooctane quenching and charge cooling. n-Heptane equivalence ratio, isooctane equivalence ratio and isooctane delivery advance angle are major control parameters. In one combustion cycle, the isooctane ignited and burned after those of n-heptane, and then this combustion phenomenon can also be named as dual-fuel sequential combustion (DFSC). The ignition timing of the overall combustion event is mainly determined by n-heptane equivalence ratio and can be controlled in flexibility by simultaneously adjusting isooctane equivalence ratio. The isooctane ignition regime, overall thermal efficiency, and NO{sub x} emissions show strong sensitivity to the fuel delivery advance angle between 20 CA BTDC and 25 CA BTDC. (author)

An Experimental Investigation on the Combustion and Heat Release Characteristics of an Opposed-Piston Folded-Cranktrain Diesel Engine

Directory of Open Access Journals (Sweden)

Fukang Ma

2015-06-01

Full Text Available In opposed-piston folded-cranktrain diesel engines, the relative movement rules of opposed-pistons, combustion chamber components and injector position are different from those of conventional diesel engines. The combustion and heat release characteristics of an opposed-piston folded-cranktrain diesel engine under different operating conditions were investigated. Four phases: ignition delay, premixed combustion, diffusion combustion and after combustion are used to describe the heat release process of the engine. Load changing has a small effect on premixed combustion duration while it influences diffusion combustion duration significantly. The heat release process has more significant isochoric and isobaric combustion which differs from the conventional diesel engine situation, except at high exhaust pressure and temperature, due to its two-stroke and uniflow scavenging characteristics. Meanwhile, a relatively high-quality exhaust heat energy is produced in opposed-piston folded-cranktrain diesel engines.

Investigation of iron current measurement to detect combustion quality; Ion denryu ni yoru nensho jotai kenshutsu no kento

Energy Technology Data Exchange (ETDEWEB)

Nakata, K; Mogi, K [Toyota Motor Corp., Aichi (Japan)

1997-10-01

The possibility and problems were investigated in detecting the combustion quality by means of ion current measured at the spark plug. The ion current has two peaks during one combustion stroke; first peak is generated by flame around the spark plug just after ignition and second one appears with the rise in temperature of burned gases. As the result of investigations, it was confirmed that the first ion peak might be useful to forecast the combustion quality, but it would be hard to practice owing to the spark duration. And the second peak offered the information of combustion chamber pressure. 4 refs., 12 figs., 1 tab.

Proceedings of the sixth international conference on fluidized bed combustion. Volume II. Technical sessions

Energy Technology Data Exchange (ETDEWEB)

None

1980-08-01

The Sixth International Conference on Fluidized Bed Combustion was held April 9-11, 1980, at the Atlanta Hilton, Atlanta, Georgia. It was sponsored by the US Department of Energy, the Electric Power Research Institute, the US Environmental Protection Agency, and the Tennessee Valley Authority. The papers covered recent developments in atmospheric and pressurized fluidized-bed combustion, especially the design, operation and control of pilot and demonstration plants. The cleanup of combustion products and the erosion, corrosion and fouling of gas turbines was emphasized also. Fifty-five papers from Volume 2 of the proceedings have been entered individually into EDB and ERA; five papers had been entered previously from other sources. (LTN)

Gasoline Engine HCCI Combustion - Extending the high load limit

Energy Technology Data Exchange (ETDEWEB)

Dahl, Daniel

2012-07-01

-way catalyst to reduce the excess NOX. Intake air boosting was also experimented on and is discussed as an alternative method or as a method to use in combination with charge stratification. During the project, experiments have been conducted with a productionlike multi-cylinder engine and a single-cylinder research engine to investigate the potential of various strategies for raising the high load limit of HCCI when using gasoline or gasoline-like fuels. To explain observed phenomena, optical experiments were conducted in which high-speed video was used to capture light from the combustion and the residuals. A method was developed to extract pressure oscillations from these measurements and to correlate them to the combustion. Laser-based experiments were further used to analyse fuel and temperature distributions before the combustion to investigate their effects on combustion and pressure oscillations. Based on the acquired data, plausible reasons why charge stratification can reduce ringing, and the circumstances in which it can do so, are presented. The thesis also shows the extent to which the load can be increased using the strategy, and the resulting efficiency penalties, observed in both the production-like gasoline engine and single-cylinder research engine. Finally, the various strategies for load extension using combinations of charge stratification, EGR and boosting were compared to operating the engine in two-stroke HCCI mode. Although two-stroke operation was investigated very briefly, in an engine not designed for it, indications were obtained that this might be a much better alternative, since it provided higher loads, more stable combustion, less ringing, low NOX levels and higher efficiency than any of the other tested load extension strategies.

A combined thermodynamic cycle used for waste heat recovery of internal combustion engine

International Nuclear Information System (INIS)

He, Maogang; Zhang, Xinxin; Zeng, Ke; Gao, Ke

2011-01-01

In this paper, we present a steady-state experiment, energy balance and exergy analysis of exhaust gas in order to improve the recovery of the waste heat of an internal combustion engine (ICE). Considering the different characteristics of the waste heat of exhaust gas, cooling water, and lubricant, a combined thermodynamic cycle for waste heat recovery of ICE is proposed. This combined thermodynamic cycle consists of two cycles: the organic Rankine cycle (ORC), for recovering the waste heat of lubricant and high-temperature exhaust gas, and the Kalina cycle, for recovering the waste heat of low-temperature cooling water. Based on Peng–Robinson (PR) equation of state (EOS), the thermodynamic parameters in the high-temperature ORC were calculated and determined via an in-house computer program. Suitable working fluids used in high-temperature ORC are proposed and the performance of this combined thermodynamic cycle is analyzed. Compared with the traditional cycle configuration, more waste heat can be recovered by the combined cycle introduced in this paper. -- Highlights: ► We study the energy balance of fuel in internal combustion engine. ► Heat recovery effect of exhaust gas is good when ICE is at a high-load condition. ► We propose a new combined thermodynamic cycle for waste heat of ICE. ► The combined cycle has a higher recovery efficiency than previous configurations.

Hydrogen enrichment of an internal combustion engine via closed loop thermochemical recuperation

NARCIS (Netherlands)

Zwitserlood, J.G.; Hofman, T.; Erickson, P.A.

2013-01-01

Hydrogen enrichment in an internal combustion engine can greatly improve efficiency and at the same time reduce emissions without the need for extensive engine modifications. One option for a hydrogen source for the enrichment is actively producing hydrogen on-board the vehicle through steam

Use of a perfume composition as a fuel for internal combustion engines

NARCIS (Netherlands)

2013-01-01

The present invention relates to fuel compositions containing perfume fractions, that is to say compositions of fragrance materials, and to the use of such perfume fractions containing fuel compositions to provide a fuel for internal combustion engines and burners. According to the present fuel

Combustion

CERN Document Server

Glassman, Irvin

2008-01-01

Combustion Engineering, a topic generally taught at the upper undergraduate and graduate level in most mechanical engineering programs, and many chemical engineering programs, is the study of rapid energy and mass transfer usually through the common physical phenomena of flame oxidation. It covers the physics and chemistry of this process and the engineering applications-from the generation of power such as the internal combustion automobile engine to the gas turbine engine. Renewed concerns about energy efficiency and fuel costs, along with continued concerns over toxic and particulate emissions have kept the interest in this vital area of engineering high and brought about new developments in both fundamental knowledge of flame and combustion physics as well as new technologies for flame and fuel control. *New chapter on new combustion concepts and technologies, including discussion on nanotechnology as related to combustion, as well as microgravity combustion, microcombustion, and catalytic combustion-all ...

Cylinder head fastening structure for internal combustion engines

Energy Technology Data Exchange (ETDEWEB)

Futakuchi, Y.; Oshiro, N.

1988-01-26

In a construction for an overhead cam internal combustion engine comprising a cylinder head adapted to be affixed to another component of the engine by at least one fastener having a tool receiving portion for tightening thereof and having a bearing cap affixed to the cylinder head and rotatably journaling the overhead camshaft, the improvement is described comprising the bearing cap having a portion overlying the fastener tool receiving portion, and means defining an access opening passing through the bearing cap and adapted to pass a tool for tightening of the fastener without removal of the bearing cap.

Internal Combustion Engine Powered by Synthesis Gas from Pyrolysed Plastics

Directory of Open Access Journals (Sweden)

Chríbik Andrej

2016-07-01

Full Text Available The article discusses the application of synthesis gas from pyrolysis of plastics in petrol engine. The appropriate experimental measurements were performed on a combustion engine LGW 702 designated for micro-cogeneration unit. The power parameters, economic parameters in term of brake specific fuel consumption, and internal parameters of the engine were compared to the engine running on the reference fuel - natural gas and synthesis gas. Burning synthesis gas leads to decreased performance by about 5% and to increased mass hourly consumption by 120 %. In terms of burning, synthesis gas has similar properties as natural gas. Compared with [5] a more detailed study has been prepared on the effects of angle of spark advance on the engine torque, giving more detailed assessment of engine cycle variability and considering specification of start and end of combustion in the logarithm p-V diagram.

Fundamental limitations of non-thermal plasma processing for internal combustion engine NOx control

International Nuclear Information System (INIS)

Penetrante, B.M.

1993-01-01

This paper discusses the physics and chemistry of non-thermal plasma processing for post-combustion NO x control in internal combustion engines. A comparison of electron beam and electrical discharge processing is made regarding their power consumption, radical production, NO x removal mechanisms, and by product formation. Can non-thermal deNO x operate efficiently without additives or catalysts? How much electrical power does it cost to operate? What are the by-products of the process? This paper addresses these fundamental issues based on an analysis of the electron-molecule processes and chemical kinetics

EXPERIMENTAL INSTALLATION FOR AN ASSESSMENT OF METHODS OF WATER SUPPLY IN AN INTERNAL COMBUSTION ENGINE

Directory of Open Access Journals (Sweden)

A. V. Bizhaev

2015-01-01

Full Text Available The water additive to fuel became one of effective ways of the solution of the main problems of the piston internal combustion engines (ICE as it reduces thermal factor of the engine, toxic emissions of exhaust products, and also increases efficiency by some operating modes. The way of fuel and air mix with water feeding in the combustion chamber has a great influence on process of combustion. Experimental installation for obtaining comparative characteristics of the main methods of water supply in the ICE combustion chamber was created. It was defined that there are two ways of water supply in the combustion chamber. At the first way water feed is carried out in the form of a water fuel emulsion which moves to the combustion chamber through a nozzle by means of the fuel pump with a high pressure. At the second way water arrives with air through the spraying element - the carburetor or a nozzle. This way is very simple in difference of emulsion feeding. The easiest way is nozzles application. It was established that the emulsion as the non-uniform highly dispersed fluid can be divide into components. Therefore it is necessary to use during the feeding system operation special emulsifiers with air for the uniformity water getting to the cylinder. The system for each nozzle opening at some point was offered. System of feedback with sensors of exhaust gases temperature in a final collector for adjustment of duration of injection was worked out. It was showed that at the developed experimental stand it is possible to carry out tests at various power modes. As result it will be possible to estimate both ways of fuel and air mix with water feeding.

PARAMETER MATCHING OF INTERNAL COMBUSTION ENGINE AND ELECTROMECHANICAL POWER TRAIN OF WHEEL TRACTOR

Directory of Open Access Journals (Sweden)

A. V. Kliuchnikov

2012-01-01

Full Text Available The paper considers stepless electromechanical power train of a wheel tractor. Methodology for parameter matching of electromechanical transmission and internal combustion engine for their optimum performance as part of a power wheel tractor unit. 

ZMOTTO- MODELING THE INTERNAL COMBUSTION ENGINE

Science.gov (United States)

Zeleznik, F. J.

1994-01-01

The ZMOTTO program was developed to model mathematically a spark-ignited internal combustion engine. ZMOTTO is a large, general purpose program whose calculations can be established at five levels of sophistication. These five models range from an ideal cycle requiring only thermodynamic properties, to a very complex representation demanding full combustion kinetics, transport properties, and poppet valve flow characteristics. ZMOTTO is a flexible and computationally economical program based on a system of ordinary differential equations for cylinder-averaged properties. The calculations assume that heat transfer is expressed in terms of a heat transfer coefficient and that the cylinder average of kinetic plus potential energies remains constant. During combustion, the pressures of burned and unburned gases are assumed equal and their heat transfer areas are assumed proportional to their respective mass fractions. Even the simplest ZMOTTO model provides for residual gas effects, spark advance, exhaust gas recirculation, supercharging, and throttling. In the more complex models, 1) finite rate chemistry replaces equilibrium chemistry in descriptions of both the flame and the burned gases, 2) poppet valve formulas represent fluid flow instead of a zero pressure drop flow, and 3) flame propagation is modeled by mass burning equations instead of as an instantaneous process. Input to ZMOTTO is determined by the model chosen. Thermodynamic data is required for all models. Transport properties and chemical kinetics data are required only as the model complexity grows. Other input includes engine geometry, working fluid composition, operating characteristics, and intake/exhaust data. ZMOTTO accommodates a broad spectrum of reactants. The program will calculate many Otto cycle performance parameters for a number of consecutive cycles (a cycle being an interval of 720 crankangle degrees). A typical case will have a number of initial ideal cycles and progress through levels

Achievement of the charge exchange work diminishing of an internal combustion engine in part load

Directory of Open Access Journals (Sweden)

Stefan POSTRZEDNIK

2012-01-01

Full Text Available Internal combustion engines, used for driving of different cars, occurs not only at full load, but mostly at the part load. The relative load exchange work at the full (nominal engine load is significantly low. At the part load of the IC engine its energy efficiency ηe is significantly lower than in the optimal (nominal field range of the performance parameters. One of the numerous reasons of this effect is regular growing of the relative load exchange work of the IC engine. It is directly connected with the quantitative regulation method commonly used in the IC engines. From the thermodynamic point of view - the main reason of this effect is the throttling process (causing exergy losses occurring in the inlet and outlet channels. The known proposals for solving of this problem are based on applying of the fully electronic control of the motion of inlet, outlet valves and new reference cycles.The idea presented in the paper leads to diminishing the charge exchange work of the IC engines. The problem can be solved using presented in the paper a new concept of the reference cycle (called as eco-cycle of IC engine. The work of the engine basing on the eco-cycle occurs in two 3-stroke stages; the fresh air is delivered only once for both stages, but in range of each stage a new portion of fuel is burned. Normally the charge exchange occurs once during each engine cycle realized. Elaborated proposition bases on the elimination of chosen charge exchange processes and through this the dropping of the charge exchange work can be achieved.

Internal combustion engines a detailed introduction to the thermodynamics of spark and compression ignition engines, their design and development

CERN Document Server

Benson, Rowland S

1979-01-01

Internal Combustion of Engines: A Detailed Introduction to the Thermodynamics of Spark and Compression Ignition Engines, Their Design and Development focuses on the design, development, and operations of spark and compression ignition engines. The book first describes internal combustion engines, including rotary, compression, and indirect or spark ignition engines. The publication then discusses basic thermodynamics and gas dynamics. Topics include first and second laws of thermodynamics; internal energy and enthalpy diagrams; gas mixtures and homocentric flow; and state equation. The text ta

Study of the strength of the internal can for internally and externally cooled fuel elements intended for gas graphite reactors; Etude de la tenue de la gaine interne pour-element combustible a refroidissement interne et externe d'un reacteur graphite-gaz

Energy Technology Data Exchange (ETDEWEB)

Boudouresque, B; Courcon, P; Lestiboubois, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

The cartridge of an internally and externally cooled annular fuel element used in gas-graphite reactors is made up of an uranium fuel tube, an external can and an internal can made of magnesium alloy. For the thermal exchange between the internal can and the fuel to be satisfactory, it is necessary for the can to stay in contact with the uranium under all temperature conditions. This report, based on a theoretical study, shows how the internal can fuel gap varies during the processes of canning, charging into the reactor and thermal cycling. The following parameters are considered: tube diameter, pressure of the heat carrying gas, gas entry temperature, plasticity of the can alloy. It is shown that for all operating conditions the internal can of a 77 x 95 element, planned for a gas-graphite reactor with a 40 kg/cm{sup 2} gas pressure, should remain in contact with the fuel. (authors) [French] La cartouche d'un element combustible annulaire, a refroidissement interne et externe pour reacteur graphite-gaz, est composee d'un tube combustible en uranium, d'une gaine externe et d'une gaine interne en alliage de magnesium. Pour que l'echange thermique entre la gaine interne et le combustible soit bon, il faut que la gaine reste appliquee sur l'uranium quel que soit le regime de temperature. Cette note a pour but de montrer comment, d'apres une etude theorique, le jeu combustible-gaine interne varie au cours des operations de gainage, de chargement dans le reacteur, et des cyclages thermiques. Les parametres suivants sont etudies: diametres de tube, pression du gaz caloporteur, temperature d'entree du gaz, plasticite de l'alliage de gaine. Il est montre que, quel que soit le regime de fonctionnement, la gaine interne d'un element 77 x 95, en projet pour un reacteur graphite-gaz sous pression de 40 kg/cm{sup 2}, doit rester appliquee sur le combustible. (auteurs)

Non-traditional Process of Hydrogen Containing Fuel Mixtures Production for Internal-combustion Engines

Directory of Open Access Journals (Sweden)

Gennady G. Kuvshinov

2012-12-01

Full Text Available The article justifies the perspectives of development of the environmentally sound technology of hydrogen containing fuel mixtures for internal-combustion engines based on the catalytic process of low-temperature decomposition of hydrocarbons into hydrogen and nanofibrous carbon.

Modelling of fuel spray and combustion in diesel engines

Energy Technology Data Exchange (ETDEWEB)

Huttunen, M T; Kaario, O T [VTT Energy, Espoo (Finland)

1998-12-31

Fuel spray and air motion characteristics and combustion in direct injection (DI) diesel engines was studied using computational models of the commercial CFD-code FIRE. Physical subprocesses modelled included Lagrangian spray droplet movement and behaviour (atomisation, evaporation and interaction of spray droplets) and combustion of evaporated liquid spray in the gas phase. Fuel vapour combustion rate was described by the model of Magnussen and Hjertager. The standard k,{epsilon}-model was used for turbulence. In order to be able to predict combustion accurately, the fuel spray penetration should be predicted with reasonable accuracy. In this study, the standard drag coefficient had to be reduced in order to match the computed penetration to the measured one. In addition, the constants in the submodel describing droplet breakup also needed to be adjusted for closer agreement with the measurements. The characteristic time scale of fuel consumption rate k/C{sub R} {epsilon} strongly influenced the heat release and in-cylinder pressure. With a value around 2.0 to 5.0 for C{sub R}, the computed in-cylinder pressure during the compression stroke agreed quite well with the measurements. On the other hand, the in-cylinder pressure was underpredicted during the expansion stroke. This is partly due to the fact that hydrocarbon fuel combustion was modelled as a one-step reaction reading to CO{sub 2} and H{sub 2}O and inadequate description of the mixing of reactants and combustion products. (author) 16 refs.

Modelling of fuel spray and combustion in diesel engines

Energy Technology Data Exchange (ETDEWEB)

Huttunen, M.T.; Kaario, O.T. [VTT Energy, Espoo (Finland)

1997-12-31

Fuel spray and air motion characteristics and combustion in direct injection (DI) diesel engines was studied using computational models of the commercial CFD-code FIRE. Physical subprocesses modelled included Lagrangian spray droplet movement and behaviour (atomisation, evaporation and interaction of spray droplets) and combustion of evaporated liquid spray in the gas phase. Fuel vapour combustion rate was described by the model of Magnussen and Hjertager. The standard k,{epsilon}-model was used for turbulence. In order to be able to predict combustion accurately, the fuel spray penetration should be predicted with reasonable accuracy. In this study, the standard drag coefficient had to be reduced in order to match the computed penetration to the measured one. In addition, the constants in the submodel describing droplet breakup also needed to be adjusted for closer agreement with the measurements. The characteristic time scale of fuel consumption rate k/C{sub R} {epsilon} strongly influenced the heat release and in-cylinder pressure. With a value around 2.0 to 5.0 for C{sub R}, the computed in-cylinder pressure during the compression stroke agreed quite well with the measurements. On the other hand, the in-cylinder pressure was underpredicted during the expansion stroke. This is partly due to the fact that hydrocarbon fuel combustion was modelled as a one-step reaction reading to CO{sub 2} and H{sub 2}O and inadequate description of the mixing of reactants and combustion products. (author) 16 refs.

Fractal and spectroscopic analysis of soot from internal combustion engines

Science.gov (United States)

Swapna, M. S.; Saritha Devi, H. V.; Raj, Vimal; Sankararaman, S.

2018-03-01

Today diesel engines are used worldwide for various applications and very importantly in transportation. Hydrocarbons are the most widespread precursors among carbon sources employed in the production of carbon nanotubes (CNTs). The aging of internal combustion engine is an important parameter in deciding the carbon emission and particulate matter due to incomplete combustion of fuel. In the present work, an attempt has been made for the effective utilization of the aged engines for potential applicationapplications in fuel cells and nanoelectronics. To analyze the impact of aging, the particulate matter rich in carbon content areis collected from diesel engines of different ages. The soot with CNTs is purified by the liquid phase oxidation method and analyzed by Field Emission Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, Energy Dispersive Spectroscopy, UV-Visible spectroscopy, Raman spectroscopy and Thermogravimetric analysis. The SEM image contains self-similar patterns probing fractal analysis. The fractal dimensions of the samples are determined by the box counting method. We could find a greater amount of single-walled carbon nanotubes (SWCNTs) in the particulate matter emitted by aged diesel engines and thereby giving information about the combustion efficiency of the engine. The SWCNT rich sample finds a wide range of applicationapplications in nanoelectronics and thereby pointing a potential use of these aged engines.

A comparison between Miller and five-stroke cycles for enabling deeply downsized, highly boosted, spark-ignition engines with ultra expansion

International Nuclear Information System (INIS)

Li, Tie; Wang, Bin; Zheng, Bin

2016-01-01

Highlights: • Deeply downsized, highly boosted SI engine with ultra-expansion cycle is studied. • The Miller and five stroke cycles are compared on BSFC improvements and WOT performance. • The mechanism of fuel conversion efficiency improvement at various loads is discussed. • Performance of the two-stage boosting system for the downsized SI engine is investigated. • A unique strategy using the bypass for the five-stroke engine is proposed. - Abstract: It has been well known that the engine downsizing combined with intake boosting is an effective way to improve the fuel conversion efficiency without penalizing the engine torque performance. However, the potential of engine downsizing is not yet fully explored, and the major hurdles include the knocking combustion and the pre-turbine temperature limit, owing to the aggressive intake boosting. Using the engine cycle simulation, this paper compares the effects of the Miller and five stroke cycles on the performance of the deeply downsized and highly boosted SI engine, taking the engine knock and pre-turbine temperature into consideration. In the simulation, the downsizing is implemented by reducing the combustion cylinder number from four to two, while a two stage boosting system is designed for the deeply downsized engine to ensure the wide-open-throttle (WOT) performance comparable to the original four cylinder engine. The Miller cycle is realized by varying the intake valve timing and lift, while the five stroke cycle is enabled with addition of an extra expansion cylinder between the two combustion cylinders. After calibration and validation of the engine cycle simulation models using the experimental data in the original engine, the performances of the deeply downsized engines with both the Miller and five stroke cycles are numerically studied. For the most frequently operated points on the torque-speed map, at low loads the Miller cycle exhibits superior performance over the five-stroke cycle in terms

Caregiver burden and emotional problems in partners of stroke patients at two months and one year post-stroke : Determinants and prediction

NARCIS (Netherlands)

Kruithof, Willeke J.; Post, Marcel W. M.; van Mierlo, Maria L.; van den Bos, Geertrudis A. M.; de Man-van Ginkel, Janneke M.; Visser-Meily, Johanna M. A.

2016-01-01

Objectives: (a) To determine levels of and factors explaining partners' burden, anxiety and depressive symptoms at two months post-stroke, (b) to predict partners' burden, anxiety and depressive symptoms at one year post-stroke based on patient and partner characteristics available at two months

A comparison of stroke rehabilitation; data from two national cohorts.

Science.gov (United States)

Bērziņa, G; Vētra, A; Sunnerhagen, K S

2016-10-01

Inpatient rehabilitation is a commonly used complex intervention to improve a person's independence after stroke. Evaluation and comparison of the effects of routine clinical practice could provide a contribution towards optimization of stroke care. The aim of this study is to describe results of inpatient rehabilitation as a complex intervention for persons after stroke and explore possible differences between two countries. Data from 1055 Latvian and 1748 Swedish adult patients after stroke receiving inpatient rehabilitation, during 2011-2013, were used for this retrospective cohort study. Qualitative description of systems, as well as information on basic medical and sociodemographic information, and organizational aspects were reported. Change in the Functional Independence Measure during rehabilitation was investigated. In six domains of the instrument, the shifts for three levels of dependence were analysed using ordinal regression analysis. The components of stroke care seem to be similar in Latvia and Sweden. However, the median time since stroke onset until the start of rehabilitation was 13 weeks in Latvia and 2 weeks in Sweden. The median length of rehabilitation was 12 and 49 days, respectively. The level of dependency at start, time since stroke onset and length of the period had an impact on the results of the rehabilitation. Although components of the rehabilitation are reported as being the same, characteristics and the outcome of the inpatient rehabilitation are different. Therefore, comparison of stroke rehabilitation between countries requires caution. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Starting procedure for internal combustion vessels

Science.gov (United States)

Harris, Harry A.

1978-09-26

A vertical vessel, having a low bed of broken material, having included combustible material, is initially ignited by a plurality of ignitors spaced over the surface of the bed, by adding fresh, broken material onto the bed to buildup the bed to its operating depth and then passing a combustible mixture of gas upwardly through the material, at a rate to prevent back-firing of the gas, while air and recycled gas is passed through the bed to thereby heat the material and commence the desired laterally uniform combustion in the bed. The procedure permits precise control of the air and gaseous fuel mixtures and material rates, and permits the use of the process equipment designed for continuous operation of the vessel.

Two-dimensional analysis of two-phase reacting flow in a firing direct-injection diesel engine

Science.gov (United States)

Nguyen, H. Lee

1989-01-01

The flow field, spray penetration, and combustion in two-stroke diesel engines are described. Fuel injection begins at 345 degrees after top dead center (ATDC) and n-dodecane is used as the liquid fuel. Arrhenius kinetics is used to calculate the reaction rate term in the quasi-global combustion model. When the temperature, fuel, and oxygen mass fraction are within suitable flammability limits, combustion begins spontaneously. No spark is necessary to ignite a localized high temperature region. Compression is sufficient to increase the gaseous phase temperature to a point where spontaneous chemical reactions occur. Results are described for a swirl angle of 22.5 degrees.

Internal combustion engines - Modelling, estimation and control issues

Energy Technology Data Exchange (ETDEWEB)

Vigild, C.W.

2001-12-01

Alternative power-trains have become buzz words in the automotive industry in the recent past. New technologies like Lithium-Ion batteries or fuel cells combined with high efficient electrical motors show promising results. However both technologies are extremely expensive and important questions like 'How are we going to supply fuel-cells with hydrogen in an environmentally friendly way?', 'How are we going to improve the range - and recharging speed - of electrical vehicles?' and 'How will our existing infrastructure cope with such changes?' are still left unanswered. Hence, the internal combustion engine with all its shortcomings is to stay with us for the next many years. What the future will really bring in this area is uncertain, but one thing can be said for sure; the time of the pipe in - pipe out engine concept is over. Modem engines, Diesel or gasoline, have in the recent past been provided with many new technologies to improve both performance and handling and to cope with the tightening emission legislations. However, as new devices are included, the number of control inputs is also gradually increased. Hence, the control matrix dimension has grown to a considerably size, and the typical table and regression based engine calibration procedures currently in use today contain both challenging and time-consuming tasks. One way to improve understanding of engines and provide a more comprehensive picture of the control problem is by use of simplified physical modelling - one of the main thrusts of this dissertation. The application of simplified physical modelling as a foundation for engine estimation and control design is first motivated by two control applications. The control problem concerns Air/Fuel ratio control of Spark Ignition engines. Two different ways of control are presented; one based on. a model based Extended Kalman Filter updated predictor, and one based on robust H {infinity} techniques. Both controllers are

7th international symposium on internal combustion diagnostics. Proceedings; 7. Internationales Symposium fuer Verbrennungsdiagnostik. Beitraege

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

At one time combustion pressure indicating was the ''trigger'' for this symposium, and today it still serves as the basis for continued investigation of combustion phenomena. It now finds application throughout the development process, as more sophisticated analysis of conventional signals is possible. Understanding of localized combustion phenomena is substantially simplified by means of optical diagnostic methods, the application of which has reached a certain level of standardization. The presentations will cover specific topics including fuel spray analysis, ignition events and information about gas mixtures. The comparison and combination of results from measurement and simulation shed light on the complex processes in the combustion chamber. What's more, the linkage of two complementary methods offers substantial cost savings through reductions in test hardware and shorter development times. Focused application of all of the available tools allows us better to understand combustion processes, recognize the influential parameters and derive control algorithms. The latter are subsequently to be found in engines that fulfill both regulatory requirements and customer expectations. So it is that the symposium captures the current state of the art in combustion diagnostics through a combination of indicating, optical diagnostics and simulation, and offers both the methodology expert and the engine developer the ideal platform for discussion of today's issues - and to form their own opinions on them. Anyone wanting to keep up to date in this continuously developing and ever more complex area of activity certainly can't afford to miss our symposium. (orig.)

Large-Eddy Simulations of Motored Flow and Combustion in a Homogeneous-Charge Spark-Ignition Engine

Science.gov (United States)

Shekhawat, Yajuvendra Singh

Cycle-to-cycle variations (CCV) of flow and combustion in internal combustion engines (ICE) limit their fuel efficiency and emissions potential. Large-eddy simulation (LES) is the most practical simulation tool to understand the nature of these CCV. In this research, multi-cycle LES of a two-valve, four-stroke, spark-ignition optical engine has been performed for motored and fired operations. The LES mesh quality is assessed using a length scale resolution parameter and a energy resolution parameter. For the motored operation, two 50-consecutive-cycle LES with different turbulence models (Smagorinsky model and dynamic structure model) are compared with the experiment. The pressure comparison shows that the LES is able to capture the wave-dynamics in the intake and exhaust ports. The LES velocity fields are compared with particle-image velocimetry (PIV) measurements at three cutting planes. Based on the structure and magnitude indices, the dynamic structure model is somewhat better than the Smagorinsky model as far as the ensemble-averaged velocity fields are concerned. The CCV in the velocity fields is assessed by proper-orthogonal decomposition (POD). The POD analysis shows that LES is able to capture the level of CCV seen in the experiment. For the fired operation, two 60-cycle LES with different combustion models (thickened frame model and coherent frame model) are compared with experiment. The in-cylinder pressure and the apparent heat release rate comparison shows higher CCV for LES compared to the experiment, with the thickened frame model showing higher CCV than the coherent frame model. The correlation analysis for the LES using thickened frame model shows that the CCV in combustion/pressure is correlated with: the tumble at the intake valve closing, the resolved and subfilter-scale kinetic energy just before spark time, and the second POD mode (shear flow near spark gap) of the velocity fields just before spark time.

Exhaust gas recirculation apparatus for internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Shigemori, M; Eguchi, N

1975-01-07

An exhaust gas recirculation device to reduce nitrogen oxides emission from internal combustion engines is described. The recirculation is achieved by employing a tube connecting between the exhaust pipe and intake tube. A throttle valve is installed within the exhaust pipe between the muffler and recirculation tube, and regulated by exhaust gas temperature. Whenever the gas temperature is high, the valve closes and increases the gas flow to the intake tube. A temperature sensor is installed within the exhaust pipe and controls a solenoid or magnetic air valve linking to the throttle valve through a relay. The recirculation tube can be cooled by a fan to improve the engine power.

Experimental and numerical studies on two-stage combustion of biomass

Energy Technology Data Exchange (ETDEWEB)

Houshfar, Eshan

2012-07-01

In this thesis, two-stage combustion of biomass was experimentally/numerically investigated in a multifuel reactor. The following emissions issues have been the main focus of the work: 1- NOx and N2O 2- Unburnt species (CO and CxHy) 3- Corrosion related emissions.The study had a focus on two-stage combustion in order to reduce pollutant emissions (primarily NOx emissions). It is well known that pollutant emissions are very dependent on the process conditions such as temperature, reactant concentrations and residence times. On the other hand, emissions are also dependent on the fuel properties (moisture content, volatiles, alkali content, etc.). A detailed study of the important parameters with suitable biomass fuels in order to optimize the various process conditions was performed. Different experimental studies were carried out on biomass fuels in order to study the effect of fuel properties and combustion parameters on pollutant emissions. Process conditions typical for biomass combustion processes were studied. Advanced experimental equipment was used in these studies. The experiments showed the effects of staged air combustion, compared to non-staged combustion, on the emission levels clearly. A NOx reduction of up to 85% was reached with staged air combustion using demolition wood as fuel. An optimum primary excess air ratio of 0.8-0.95 was found as a minimizing parameter for the NOx emissions for staged air combustion. Air staging had, however, a negative effect on N2O emissions. Even though the trends showed a very small reduction in the NOx level as temperature increased for non-staged combustion, the effect of temperature was not significant for NOx and CxHy, neither in staged air combustion or non-staged combustion, while it had a great influence on the N2O and CO emissions, with decreasing levels with increasing temperature. Furthermore, flue gas recirculation (FGR) was used in combination with staged combustion to obtain an enhanced NOx reduction. The

Repurposing Mass-produced Internal Combustion Engines Quantifying the Value and Use of Low-cost Internal Combustion Piston Engines for Modular Applications in Energy and Chemical Engineering Industries

Science.gov (United States)

L'Heureux, Zara E.

This thesis proposes that internal combustion piston engines can help clear the way for a transformation in the energy, chemical, and refining industries that is akin to the transition computer technology experienced with the shift from large mainframes to small personal computers and large farms of individually small, modular processing units. This thesis provides a mathematical foundation, multi-dimensional optimizations, experimental results, an engine model, and a techno-economic assessment, all working towards quantifying the value of repurposing internal combustion piston engines for new applications in modular, small-scale technologies, particularly for energy and chemical engineering systems. Many chemical engineering and power generation industries have focused on increasing individual unit sizes and centralizing production. This "bigger is better" concept makes it difficult to evolve and incorporate change. Large systems are often designed with long lifetimes, incorporate innovation slowly, and necessitate high upfront investment costs. Breaking away from this cycle is essential for promoting change, especially change happening quickly in the energy and chemical engineering industries. The ability to evolve during a system's lifetime provides a competitive advantage in a field dominated by large and often very old equipment that cannot respond to technology change. This thesis specifically highlights the value of small, mass-manufactured internal combustion piston engines retrofitted to participate in non-automotive system designs. The applications are unconventional and stem first from the observation that, when normalized by power output, internal combustion engines are one hundred times less expensive than conventional, large power plants. This cost disparity motivated a look at scaling laws to determine if scaling across both individual unit size and number of units produced would predict the two order of magnitude difference seen here. For the first

Simulation and experiment for oxygen-enriched combustion engine using liquid oxygen to solidify CO2

Science.gov (United States)

Liu, Yongfeng; Jia, Xiaoshe; Pei, Pucheng; Lu, Yong; Yi, Li; Shi, Yan

2016-01-01

For capturing and recycling of CO2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation (EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52FMI engine is transformed and the CO2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80-437.40 g is imported into the device and last 1-20 min, respectively, 21.50-701.30 g dry ice is obtained. This research proposes a new design method which can capture CO2 for vehicular internal combustion engine.

Enhanced efficiency of internal combustion engines by employing spinning gas.

Science.gov (United States)

Geyko, V I; Fisch, N J

2014-08-01

The efficiency of the internal combustion engine might be enhanced by employing spinning gas. A gas spinning at near sonic velocities has an effectively higher heat capacity, which allows practical fuel cycles, which are far from the Carnot efficiency, to approach more closely the Carnot efficiency. A remarkable gain in fuel efficiency is shown to be theoretically possible for the Otto and Diesel cycles. The use of a flywheel, in principle, could produce even greater increases in efficiency.

Conversion of a micro, glow-ignition, two-stroke engine from nitromethane-methanol blend fuel to military jet propellant (JP-8)

Science.gov (United States)

Wiegand, Andrew L.

The goal of the thesis "Conversion of a Micro, Glow-Ignition, Two-Stroke Engine from Nitromethane-Methanol Blend Fuel to Military Jet Propellant (JP-8)" was to demonstrate the ability to operate a small engine on JP-8 and was completed in two phases. The first phase included choosing, developing a test stand for, and baseline testing a nitromethane-methanol-fueled engine. The chosen engine was an 11.5 cc, glow-ignition, two-stroke engine designed for remote-controlled helicopters. A micro engine test stand was developed to load and motor the engine. Instrumentation specific to the low flow rates and high speeds of the micro engine was developed and used to document engine behavior. The second phase included converting the engine to operate on JP-8, completing JP-8-fueled steady-state testing, and comparing the performance of the JP-8-fueled engine to the nitromethane-methanol-fueled engine. The conversion was accomplished through a novel crankcase heating method; by heating the crankcase for an extended period of time, a flammable fuel-air mixture was generated in the crankcase scavenged engine, which greatly improved starting times. To aid in starting and steady-state operation, yttrium-zirconia impregnated resin (i.e. ceramic coating) was applied to the combustion surfaces. This also improved the starting times of the JP-8-fueled engine and ultimately allowed for a 34-second starting time. Finally, the steady-state data from both the nitromethane-methanol and JP-8-fueled micro engine were compared. The JP-8-fueled engine showed signs of increased engine friction while having higher indicated fuel conversion efficiency and a higher overall system efficiency. The minimal ability of JP-8 to cool the engine via evaporative effects, however, created the necessity of increased cooling air flow. The conclusion reached was that JP-8-fueled micro engines could be viable in application, but not without additional research being conducted on combustion phenomenon and

Combustion Research Facility

Data.gov (United States)

Federal Laboratory Consortium — For more than 30 years The Combustion Research Facility (CRF) has served as a national and international leader in combustion science and technology. The need for a...

Method for operating a spark-ignition, direct-injection internal combustion engine

Science.gov (United States)

Narayanaswamy, Kushal; Koch, Calvin K.; Najt, Paul M.; Szekely, Jr., Gerald A.; Toner, Joel G.

2015-06-02

A spark-ignition, direct-injection internal combustion engine is coupled to an exhaust aftertreatment system including a three-way catalytic converter upstream of an NH3-SCR catalyst. A method for operating the engine includes operating the engine in a fuel cutoff mode and coincidentally executing a second fuel injection control scheme upon detecting an engine load that permits operation in the fuel cutoff mode.

Cradle-to-gate greenhouse gas emissions of battery electric and internal combustion engine vehicles in China

International Nuclear Information System (INIS)

Qiao, Qinyu; Zhao, Fuquan; Liu, Zongwei; Jiang, Shuhua; Hao, Han

2017-01-01

Highlights: •Cradle-to-gate greenhouse gas emissions of internal combustion engine and battery electric vehicles are compared. •Greenhouse gas emissions of battery electric vehicles are 50% higher than internal combustion engine vehicles. •Traction battery production causes about 20% greenhouse gas emissions increase. •10% variations of curb weight, electricity and Li-ion battery production affect the results by 7%, 4% and 2%. •Manufacturing technique improvement, vehicle recycling and energy structure optimization are major mitigation opportunities. -- Abstract: Electric drive vehicles are equipped with totally different propulsion systems compared with conventional vehicles, for which the energy consumption and cradle-to-gate greenhouse gas emissions associated with vehicle production could substantially change. In this study, the life cycle energy consumption and greenhouse gas emissions of vehicle production are compared between battery electric and internal combustion engine vehicles in China’s context. The results reveal that the energy consumption and greenhouse gas emissions of a battery electric vehicle production range from 92.4 to 94.3 GJ and 15.0 to 15.2 t CO 2 eq, which are about 50% higher than those of an internal combustion engine vehicle, 63.5 GJ and 10.0 t CO 2 eq. This substantial change can be mainly attributed to the production of traction batteries, the essential components for battery electric vehicles. Moreover, the larger weight and different weight distribution of materials used in battery electric vehicles also contribute to the larger environmental impact. This situation can be improved through the development of new traction battery production techniques, vehicle recycling and a low-carbon energy structure.

Construction of combustion models for rapeseed methyl ester bio-diesel fuel for internal combustion engine applications.

Science.gov (United States)

Golovitchev, Valeri I; Yang, Junfeng

2009-01-01

Bio-diesel fuels are non-petroleum-based diesel fuels consisting of long chain alkyl esters produced by the transesterification of vegetable oils, that are intended for use (neat or blended with conventional fuels) in unmodified diesel engines. There have been few reports of studies proposing theoretical models for bio-diesel combustion simulations. In this study, we developed combustion models based on ones developed previously. We compiled the liquid fuel properties, and the existing detailed mechanism of methyl butanoate ester (MB, C(5)H(10)O(2)) oxidation was supplemented by sub-mechanisms for two proposed fuel constituent components, C(7)H(16) and C(7)H(8)O (and then, by mp2d, C(4)H(6)O(2) and propyne, C(3)H(4)) to represent the combustion model for rapeseed methyl ester described by the chemical formula, C(19)H(34)O(2) (or C(19)H(36)O(2)). The main fuel vapor thermal properties were taken as those of methyl palmitate C(19)H(36)O(2) in the NASA polynomial form of the Burcat database. The special global reaction was introduced to "crack" the main fuel into its constituent components. This general reaction included 309 species and 1472 reactions, including soot and NO(x) formation processes. The detailed combustion mechanism was validated using shock-tube ignition-delay data under diesel engine conditions. For constant volume and diesel engine (Volvo D12C) combustion modeling, this mechanism could be reduced to 88 species participating in 363 reactions.

A report of heat stroke in two Nigerian siblings

African Journals Online (AJOL)

2014-05-31

May 31, 2014 ... Two Nigerian siblings aged ... Case Report. Two male siblings, aged 3 (Case 1) and 5‑year‑old (Case 2) ... stroke with the resultant neurological and multi organ dysfunction,[11] ... urine color cleared within 24 h of admission.

Aerodynamic efficiency of flapping flight: analysis of a two-stroke model.

Science.gov (United States)

Wang, Z Jane

2008-01-01

To seek the simplest efficient flapping wing motions and understand their relation to steady flight, a two-stroke model in the quasi-steady limit was analyzed. It was found that a family of two-stroke flapping motions have aerodynamic efficiency close to, but slightly lower than, the optimal steady flight. These two-stroke motions share two common features: the downstroke is a gliding motion and the upstroke has an angle of attack close to the optimal of the steady flight of the same wing. With the reduced number of parameters, the aerodynamic cost function in the parameter space can be visualized. This was examined for wings of different lift and drag characteristics at Reynolds numbers between 10(2) and 10(6). The iso-surfaces of the cost function have a tube-like structure, implying that the solution is insensitive to a specific direction in the parameter space. Related questions in insect flight that motivated this work are discussed.

Internal combustion engine system having a power turbine with a broad efficiency range

Science.gov (United States)

Whiting, Todd Mathew; Vuk, Carl Thomas

2010-04-13

An engine system incorporating an air breathing, reciprocating internal combustion engine having an inlet for air and an exhaust for products of combustion. A centripetal turbine receives products of the combustion and has a housing in which a turbine wheel is rotatable. The housing has first and second passages leading from the inlet to discrete, approximately 180.degree., portions of the circumference of the turbine wheel. The passages have fixed vanes adjacent the periphery of the turbine wheel and the angle of the vanes in one of the passages is different than those in the other so as to accommodate different power levels providing optimum approach angles between the gases passing the vanes and the blades of the turbine wheel. Flow through the passages is controlled by a flapper valve to direct it to one or the other or both passages depending upon the load factor for the engine.

Supratentorial arterial ischemic stroke following cerebellar tumor resection in two children.

Science.gov (United States)

Catsman-Berrevoets, Coriene E; van Breemen, Melanie; van Veelen, Marie Lise; Appel, Inge M; Lequin, Maarten H

2005-01-01

We describe two children who developed ischemic strokes in the territory of the middle cerebral artery, one 7 days and one 11 days after resection of a cerebellar tumor. In the first child, another infarction occurred in the territory of the contralateral middle cerebral artery 5 days after the first stroke. No specific cause or underlying risk factor other than the surgical procedure was found. The subacute clinical course at stroke onset resembled that of the 'posterior fossa syndrome', suggesting a common underlying mechanism.

7th international symposium on internal combustion diagnostics. Proceedings; 7. Internationales Symposium fuer Verbrennungsdiagnostik. Beitraege

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

At one time combustion pressure indicating was the ''trigger'' for this symposium, and today it still serves as the basis for continued investigation of combustion phenomena. It now finds application throughout the development process, as more sophisticated analysis of conventional signals is possible. Understanding of localized combustion phenomena is substantially simplified by means of optical diagnostic methods, the application of which has reached a certain level of standardization. The presentations will cover specific topics including fuel spray analysis, ignition events and information about gas mixtures. The comparison and combination of results from measurement and simulation shed light on the complex processes in the combustion chamber. What's more, the linkage of two complementary methods offers substantial cost savings through reductions in test hardware and shorter development times. Focused application of all of the available tools allows us better to understand combustion processes, recognize the influential parameters and derive control algorithms. The latter are subsequently to be found in engines that fulfill both regulatory requirements and customer expectations. So it is that the symposium captures the current state of the art in combustion diagnostics through a combination of indicating, optical diagnostics and simulation, and offers both the methodology expert and the engine developer the ideal platform for discussion of today's issues - and to form their own opinions on them. Anyone wanting to keep up to date in this continuously developing and ever more complex area of activity certainly can't afford to miss our symposium. (orig.)

A stochastic logical system approach to model and optimal control of cyclic variation of residual gas fraction in combustion engines

International Nuclear Information System (INIS)

Wu, Yuhu; Kumar, Madan; Shen, Tielong

2016-01-01

Highlights: • An in-cylinder pressure based measuring method for the RGF is derived. • A stochastic logical dynamical model is proposed to represent the transient behavior of the RGF. • The receding horizon controller is designed to reduce the variance of the RGF. • The effectiveness of the proposed model and control approach is validated by the experimental evidence. - Abstract: In four stroke internal combustion engines, residual gas from the previous cycle is an important factor influencing the combustion quality of the current cycle, and the residual gas fraction (RGF) is a popular index to monitor the influence of residual gas. This paper investigates the cycle-to-cycle transient behavior of the RGF in the view of systems theory and proposes a multi-valued logic-based control strategy for attenuation of RGF fluctuation. First, an in-cylinder pressure sensor-based method for measuring the RGF is provided by following the physics of the in-cylinder transient state of four-stroke internal combustion engines. Then, the stochastic property of the RGF is examined based on statistical data obtained by conducting experiments on a full-scale gasoline engine test bench. Based on the observation of the examination, a stochastic logical transient model is proposed to represent the cycle-to-cycle transient behavior of the RGF, and with the model an optimal feedback control law, which targets on rejection of the RGF fluctuation, is derived in the framework of stochastic logical system theory. Finally, experimental results are demonstrated to show the effectiveness of the proposed model and the control strategy.

Development of Explosive Ripper with Two-Stage Combustion

Science.gov (United States)

1974-10-01

inch pipe duct work, the width of this duct proved to be detrimental in marginally rippable material; the duct, instead of the penetrator tip, was...marginally rippable rock. ID. Operating Requirements 2. Fuel The two-stage combustion device is designed to operate using S A 42. the same diesel

Reliability and validity of the Korean standard pattern identification for stroke (K-SPI-Stroke questionnaire

Directory of Open Access Journals (Sweden)

Kang Byoung-Kab

2012-04-01

Full Text Available Abstract Background The present study was conducted to examine the reliability and validity of the ‘Korean Standard Pattern Identification for Stroke (K-SPI-Stroke’, which was developed and evaluated within the context of traditional Korean medicine (TKM. Methods Between September 2006 and December 2010, 2,905 patients from 11 Korean medical hospitals were asked to complete the K-SPI-Stroke questionnaire as a part of project ' Fundamental study for the standardization and objectification of pattern identification in traditional Korean medicine for stroke (SOPI-Stroke. Each patient was independently diagnosed by two TKM physicians from the same site according to one of four patterns, as suggested by the Korea Institute of Oriental Medicine: 1 a Qi deficiency pattern, 2 a Dampness-phlegm pattern, 3 a Yin deficiency pattern, or 4 a Fire-heat pattern. We estimated the internal consistency using Cronbach’s α coefficient, the discriminant validity using the means score of patterns, and the predictive validity using the classification accuracy of the K-SPI-Stroke questionnaire. Results The K-SPI-Stroke questionnaire had satisfactory internal consistency (α = 0.700 and validity, with significant differences in the mean of scores among the four patterns. The overall classification accuracy of this questionnaire was 65.2 %. Conclusion These results suggest that the K-SPI-Stroke questionnaire is a reliable and valid instrument for estimating the severity of the four patterns.

Particulate matter regulation for two-stroke two wheelers: necessity or haphazard legislation?

NARCIS (Netherlands)

Rijkeboer, R.C.; Bremmers, D.A.C.M.; Samaras, Z.; Ntziachristos, L.

2005-01-01

Although interest in particulate emissions has increased considerably during recent years, the subject of particulate matter (PM) emissions from small two-stroke engines used in road vehicles is still largely unexplored. This paper presents the results of an investigation, which examined the typical

Direct injection of gaseous LPG in a two-stroke SI engine for improved performance

International Nuclear Information System (INIS)

Pradeep, V.; Bakshi, Shamit; Ramesh, A.

2015-01-01

Improvements in a two-stroke, spark-ignition (2S–SI) engine can be realized by curtailing short-circuiting losses effectively through direct injection of the fuel. Liquefied petroleum gas (LPG) is an alternative transportation fuel that is used in several countries. However, limited information is available on LPG fuelled direct injected engines. Hence, there is a need to study these systems as applied to 2S–SI engines in order to bring out their potential benefits. A manifold injected 2S–SI engine is modified for direct injection of LPG, in gaseous form, from the cylinder head. This engine is evaluated for performance, emission and combustion. Evaluation at various throttle positions and constant speed showed that this system can significantly improve the thermal efficiency and lower the hydrocarbon (HC) emissions. Up to 93% reduction in HC emissions and improved combustion rates are observed compared to the conventional manifold injection system with LPG. CO emissions are higher and peak NO emissions are lower with this system due to the presence of richer in–cylinder trapped mixtures and charge stratification. This system can operate with similar injection timings at different throttle positions which make electronic control simpler. It can work with low injection pressures in the range of 4–5 bars. All these advantages are attractive for commercial viability of this engine. - Highlights: • Energy saving, low pressure, direct gaseous LPG injection in engine. • Significant reduction in HC emissions at all operating conditions. • No significant changes in injection timings for different throttle positions.

Impact of banning of two-stroke engines on airborne particulate matter concentrations in Dhaka, Bangladesh.

Science.gov (United States)

Begum, Bilkis A; Biswas, Swapan K; Hopke, Philip K

2006-01-01

Vehicular air pollution is common in growing metropolitan areas throughout the world. Vehicular emissions of fine particles are particularly harmful because they occur near ground level, close to where people live and work. Two-stroke engines represented an important contribution to the motor vehicle emissions where they constitute approximately half of the total vehicle fleet in Dhaka city. Two-stroke engines have lower fuel efficiency than four-stroke engines, and they emit as much of an order of magnitude and more particulate matter (PM) than four-stroke engines of similar size. To eliminate their impact on air quality, the government of Bangladesh promulgated an order banning all two-stroke engines from the roads in Dhaka starting on December 31, 2002. The effect of the banning of two-stroke engines on airborne PM was studied at the Farm Gate air quality-monitoring station in Dhaka (capital of Bangladesh), a hot spot with very high-pollutant concentrations because of its proximity to major roadways. The samples were collected using a "Gent" stacked filter unit in two fractions of 0-2.2 microm and 2.2-10 microm sizes. Samples of fine and coarse fractions of airborne PM collected from 2000 to 2004 were studied. It has been found that the fine PM and black carbon concentrations decreased from the previous years because of the banning of two-stroke engine baby taxies.

Industrial Education. "Small Engines".

Science.gov (United States)

Parma City School District, OH.

Part of a series of curriculum guides dealing with industrial education in junior high schools, this guide provides the student with information and manipulative experiences on small gasoline engines. Included are sections on shop adjustment, safety, small engines, internal combustion, engine construction, four stroke engines, two stroke engines,…

In-hospital stroke: characteristics and outcomes.

LENUS (Irish Health Repository)

Briggs, R

2015-01-01

In-hospital stroke (IS) made up 6.5% of strokes recorded in the Irish National Stroke Register in 2012. International research has demonstrated poorer outcomes post IS compared to out of hospital stroke (OS). We aimed to profile all IS and OS over a 22 month period and compare the two groups by gathering data from the HIPE portal stroke register. The study site is a primary stroke centre. IS represented 11% (50\\/458) of total strokes with over half (27\\/50, 54%) admitted initially with medical complaints. IS patients had a significantly longer length of stay (79.2 +\\/- 87.4 days vs. 21.9 +\\/- 45.9 days, p < 0.01) and higher mortality (13\\/50 vs. 39\\/408, p < 0.01). Patients in the IS group were also less likely to receive stroke unit care (1\\/50 vs. 136\\/408, p < 0.01). This study demonstrates the significant morbidity and mortality associated with IS and highlights the need for efforts to be made to optimize identification and management of acute stroke in this cohort.

Alcohol combustion chemistry

KAUST Repository

Sarathy, Mani; Oß wald, Patrick; Hansen, Nils; Kohse-Hö inghaus, Katharina

2014-01-01

. While biofuel production and its use (especially ethanol and biodiesel) in internal combustion engines have been the focus of several recent reviews, a dedicated overview and summary of research on alcohol combustion chemistry is still lacking. Besides

Analysis of Combustion Process in Industrial Gas Engine with Prechamber-Based Ignition System

Directory of Open Access Journals (Sweden)

Rafał Ślefarski

2018-02-01

Full Text Available Application of a pre-combustion chamber (PCC ignition system is one of the methods to improve combustion stability and reduce toxic compounds emission, especially NOx. Using PCC allows the operation of the engine at lean combustion conditions or the utilization of low calorific gaseous fuels such as syngas or biogas. The paper presents the results of an experimental study of the combustion process in two stroke, large bore, stationary gas engine GMVH 12 equipped with two spark plugs (2-SP and a PCC ignition system. The experimental research has been performed during the normal operation of the engine in an industrial compression station. It was observed that application of PCC provides less cycle-to-cycle combustion variation (more than 10% and nitric oxide and carbon monoxide emissions decreased to 60% and 26% respectively. The total hydrocarbon (THC emission rate is 25% higher for the engine equipped with PCC, which results in roughly two percent engine efficiency decrease. Another important criterion of engine retrofitting was the PCC location in the engine head. The experimental results show that improvement of engine operating parameters was recorded only for a configuration with one port offset by 45° from the axis of the main chamber. The study of the ignition delay angle and equivalence ratio in PCC did not demonstrate explicit influence on engine performance.

Swirling flow in a two-stroke marine diesel engine

DEFF Research Database (Denmark)

Hemmingsen, Casper Schytte; Ingvorsen, Kristian Mark; Walther, Jens Honore

2013-01-01

Computational fluid dynamic simulations are performed for the turbulent swirling flow in a scale model of a low-speed two-stroke diesel engine with a moving piston. The purpose of the work is to investigate the accuracy of different turbulence models including two-equation Reynolds- Averaged Navier...

Two-stage combustion for reducing pollutant emissions from gas turbine combustors

Science.gov (United States)

Clayton, R. M.; Lewis, D. H.

1981-01-01

Combustion and emission results are presented for a premix combustor fueled with admixtures of JP5 with neat H2 and of JP5 with simulated partial-oxidation product gas. The combustor was operated with inlet-air state conditions typical of cruise power for high performance aviation engines. Ultralow NOx, CO and HC emissions and extended lean burning limits were achieved simultaneously. Laboratory scale studies of the non-catalyzed rich-burning characteristics of several paraffin-series hydrocarbon fuels and of JP5 showed sooting limits at equivalence ratios of about 2.0 and that in order to achieve very rich sootless burning it is necessary to premix the reactants thoroughly and to use high levels of air preheat. The application of two-stage combustion for the reduction of fuel NOx was reviewed. An experimental combustor designed and constructed for two-stage combustion experiments is described.

Design and experimental investigations on six-stroke SI engine using acetylene with water injection.

Science.gov (United States)

Gupta, Keshav; Suthar, Kishanlal; Jain, Sheetal Kumar; Agarwal, Ghanshyam Das; Nayyar, Ashish

2018-06-02

In the present study, a four-stroke cycle gasoline engine is redesigned and converted into a six-stroke cycle engine and experimental study has been conducted using gasoline and acetylene as fuel with water injection at the end of the recompression stroke. Acetylene has been used as an alternative fuel along with gasoline and performance of the six-stroke spark ignition (SI) engine with these two fuels has been studied separately and compared. Brake power and thermal efficiency are found to be 5.18 and 1.55% higher with acetylene as compared to gasoline in the six-stroke engine. However, thermal efficiency is found to be 45% higher with acetylene in the six-stroke engine as compared to four-stroke SI engine. The CO and HC emissions were found to be reduced by 13.33 and 0.67% respectively with acetylene as compared to gasoline due to better combustion of acetylene. The NO x emission was reduced by 5.65% with acetylene due to lower peak temperature by water injection. The experimental results showed better engine performance and emissions with acetylene as fuel in the six-stroke engine.

Knowledge of stroke among stroke patients and their relatives in Northwest India.

Science.gov (United States)

Pandian, Jeyaraj Durai; Kalra, Guneet; Jaison, Ashish; Deepak, Sukhbinder Singh; Shamsher, Shivali; Singh, Yashpal; Abraham, George

2006-06-01

The knowledge of warning symptoms and risk factors for stroke has not been studied among patients with stroke in developing countries. We aimed to assess the knowledge of stroke among patients with stroke and their relatives. Prospective tertiary referral hospital-based study in Northwest India. Trained nurses and medical interns interviewed patients with stroke and transient ischemic attack and their relatives about their knowledge of stroke symptoms and risk factors. Univariable and multivariable logistic regression were used. Of the 147 subjects interviewed, 102 (69%) were patients and 45 (31%) were relatives. There were 99 (67%) men and 48 (33%) women and the mean age was 59.7+/-14.1 years. Sixty-two percent of respondents recognized paralysis of one side as a warning symptom and 54% recognized hypertension as a risk factor for stroke. In the multivariable logistic regression analysis, higher education was associated with the knowledge of correct organ involvement in stroke (OR 2.6, CI 1.1- 6.1, P =0.02), whereas younger age (OR 2.7, CI 1.1-7.0, P =0.04) and higher education (OR 4.1, CI 1.5-10.9, P =0.005) correlated with a better knowledge regarding warning symptoms of stroke. In this study cohort, in general, there is lack of awareness of major warning symptoms, risk factors, organ involvement and self-recognition of stroke. However younger age and education status were associated with better knowledge. There is an urgent need for awareness programs about stroke in this study cohort.

Small Engines as Bottoming Cycle Steam Expanders for Internal Combustion Engines

OpenAIRE

Weerasinghe, Rohitha; Hounsham, Sandra

2017-01-01

Heat recovery bottoming cycles for internal combustion engines have opened new avenues for research into small steam expanders [1]. Dependable data for small steam expanders will allow us to predict on their suitability as bottoming cycle engines and the fuel economy achieved by using them as bottoming cycles. Wankel Engines, with its lower resistance properties at small scale provide excellent contenders for bottoming cycle expanders. Present paper is based on results of experiments carried ...

Auto-ignition control in turbocharged internal combustion engines operating with gaseous fuels

International Nuclear Information System (INIS)

Duarte, Jorge; Amador, Germán; Garcia, Jesus; Fontalvo, Armando; Vasquez Padilla, Ricardo; Sanjuan, Marco; Gonzalez Quiroga, Arturo

2014-01-01

Control strategies for auto-ignition control in turbocharged internal combustion engines operating with gaseous fuels are presented. Ambient temperature and ambient pressure are considered as the disturbing variables. A thermodynamic model for predicting temperature at the ignition point is developed, adjusted and validated with a large experimental data-set from high power turbocharged engines. Based on this model, the performance of feedback and feedforward auto-ignition control strategies is explored. A robustness and fragility analysis for the Feedback control strategies is presented. The feedforward control strategy showed the best performance however its implementation entails adding a sensor and new control logic. The proposed control strategies and the proposed thermodynamic model are useful tools for increasing the range of application of gaseous fuels with low methane number while ensuring a safe running in internal combustion engines. - Highlights: • A model for predicting temperature at the ignition point. • Robust PID, modified PID, and feedforward strategies for auto-ignition control. • λ′ were the best set of tuning equations for calculating controller parameters. • Robust PID showed significant improvements in auto-ignition control. • Feedforward control showed the best performance

Engine modeling and control modeling and electronic management of internal combustion engines

CERN Document Server

Isermann, Rolf

2014-01-01

The increasing demands for internal combustion engines with regard to fuel consumption, emissions and driveability lead to more actuators, sensors and complex control functions. A systematic implementation of the electronic control systems requires mathematical models from basic design through simulation to calibration. The book treats physically-based as well as models based experimentally on test benches for gasoline (spark ignition) and diesel (compression ignition) engines and uses them for the design of the different control functions. The main topics are: - Development steps for engine control - Stationary and dynamic experimental modeling - Physical models of intake, combustion, mechanical system, turbocharger, exhaust, cooling, lubrication, drive train - Engine control structures, hardware, software, actuators, sensors, fuel supply, injection system, camshaft - Engine control methods, static and dynamic feedforward and feedback control, calibration and optimization, HiL, RCP, control software developm...

Study of boron behaviour in two Spanish coal combustion power plants.

Science.gov (United States)

Ochoa-González, Raquel; Cuesta, Aida Fuente; Córdoba, Patricia; Díaz-Somoano, Mercedes; Font, Oriol; López-Antón, M Antonia; Querol, Xavier; Martínez-Tarazona, M Rosa; Giménez, Antonio

2011-10-01

A full-scale field study was carried out at two Spanish coal-fired power plants equipped with electrostatic precipitator (ESP) and wet flue gas desulfurisation (FGD) systems to investigate the distribution of boron in coals, solid by-products, wastewater streams and flue gases. The results were obtained from the simultaneous sampling of solid, liquid and gaseous streams and their subsequent analysis in two different laboratories for purposes of comparison. Although the final aim of this study was to evaluate the partitioning of boron in a (co-)combustion power plant, special attention was paid to the analytical procedure for boron determination. A sample preparation procedure was optimised for coal and combustion by-products to overcome some specific shortcomings of the currently used acid digestion methods. In addition boron mass balances and removal efficiencies in ESP and FGD devices were calculated. Mass balance closures between 83 and 149% were obtained. During coal combustion, 95% of the incoming boron was collected in the fly ashes. The use of petroleum coke as co-combustible produced a decrease in the removal efficiency of the ESP (87%). Nevertheless, more than 90% of the remaining gaseous boron was eliminated via the FGD in the wastewater discharged from the scrubber, thereby causing environmental problems. Copyright © 2011 Elsevier Ltd. All rights reserved.

Internal combustion engine exhaust pipe flow simulation. Part I: theoretical aspects

OpenAIRE

Juan Miguel Mantilla; Camilo Andrés Falla; Jorge Arturo Gómez

2010-01-01

Unsteady gas flow theory can be used for simulating a spark ignition internal combustion engine’s exhaust system, using pressure waves. The method explained here is based on the discretization of interpolated spaces (called meshes) which are located throughout the whole length of the exhaust pipe, irrespective of its form or size. The most important aspects of this theory are theoretically explored, such as pressure wave movement and shock and their application to cases found in re...

Internal combustion engine exhaust pipe flow simulation. Part I: theoretical aspects

OpenAIRE

Juan Miguel Mantilla; Camilo Andrés Falla; Jorge Arturo Gómez

2009-01-01

Unsteady gas flow theory can be used for simulating a spark ignition internal combustion engine’s exhaust system, using pressure waves. The method explained here is based on the discretization of interpolated spaces (called meshes) which are located throughout the whole length of the exhaust pipe, irrespective of its form or size. The most important aspects of this theory are theoretically explored, such as pressure wave movement and shock and their application to cases found in real engines’...

Post-stroke depression among stroke survivors attending two ...

African Journals Online (AJOL)

African Health Sci

The Patient Health Questionnaire-9 was used to assess for depression ... Stroke is a common neurological problem and one of ... students. Nsambya hospital is a private not for profit, church aided institution, while Mulago is a government.

Stroke care: Experiences and clinical research in stroke units in Chennai

Directory of Open Access Journals (Sweden)

Gobindram Arjundas

2006-01-01

Full Text Available Background: S troke is the second commonest cause of death in India with crude overall prevalence rate of 220 per 100,000. With an increasing aging population at risk, the stroke burden in India can be expected to reach epidemic proportions. Materials and Methods: The first protocol-based prospective studies, funded by private agencies was conducted in Madras Institute of Neurology in 1984-86. The results led to establishment of the first stroke unit in Tamil Nadu state, in the institute. The first all-India hospital-based studies in acute stroke was completed as INDIAN COOPERATIVE ACUTE STROKE STUDIES (ICASS I and ICASS II with WHO STEP ONE by members of the Indian Stroke Association between 2000-2005. This has generated very useful data for our country. Results: Mortality in 1984-86 was 40%. Stroke unit in the institute dropped it to 12%. About 10 years later, ICASS studies showed a further fall of mortality to 8%, which is the current international figure in the west. Morbidity pattern showed about half return to their original activities. But about one third are left totally disabled needing prolonged care, for which fiscal, social and rehab provisions have to be done on a national basis. Conclusions: The progress and success of care of Stroke in the last three decades, from treatment in medical and neurology wards to specialized stroke units is presented. The main risk factors are hypertension, diabetes and ischemic heart disease across the country. Hypertension alone or with the other two diseases was present in 72% of cases. Prevention and treatment of these factors will reduce the stroke burden, mortality and morbidity of strokes. The Stroke-team concept can be extended to the smallest hospitals in our country.

A diagnostic test for apraxia in stroke patients: internal consistency and diagnostic value.

NARCIS (Netherlands)

Heugten, C.M. van; Dekker, J.; Deelman, B.G.; Stehmann-Saris, F.C.; Kinebanian, A.

1999-01-01

The internal consistency and the diagnostic value of a test for apraxia in patients having had a stroke are presented. Results indicate that the items of the test form a strong and consistent scale: Cronbach's alpha as well as the results of a Mokken scale analysis present good reliability and good

The Thermodynamics of Internal Combustion Engines: Examples of Insights

Directory of Open Access Journals (Sweden)

Jerald A. Caton

2018-05-01

Full Text Available A major goal of the development of internal combustion (IC engines continues to be higher performance and efficiencies. A major aspect of achieving higher performance and efficiencies is based on fundamental thermodynamics. Both the first and second laws of thermodynamics provide strategies for and limits to the thermal efficiencies of engines. The current work provides three examples of the insights that thermodynamics provides to the performance and efficiencies of an IC engine. The first example evaluates low heat rejection engine concepts, and, based on thermodynamics, demonstrates the difficulty of this concept for increasing efficiencies. The second example compares and contrasts the thermodynamics associated with external and internal exhaust gas dilution. Finally, the third example starts with a discussion of the Otto cycle analysis and explains why this is an incorrect model for the IC engine. An important thermodynamic property that is responsible for many of the observed effects is specific heat.

Recent Development of the Two-Stroke Engine. II - Design Features. 2; Design Features

Science.gov (United States)

Zeman, J.

1945-01-01

Completing the first paper dealing with charging methods and arrangements, the present paper discusses the design forms of two-stroke engines. Features which largely influence piston running are: (a) The shape and surface condition of the sliding parts. (b) The cylinder and piston materials. (c) Heat conditions in the piston, and lubrication. There is little essential difference between four-stroke and two-stroke engines with ordinary pistons. In large engines, for example, are always found separately cast or welded frames in which the stresses are taken up by tie rods. Twin piston and timing piston engines often differ from this design. Examples can be found in many engines of German or foreign make. Their methods of operation will be dealt with in the third part of the present paper, which also includes the bibliography. The development of two-stroke engine design is, of course, mainly concerned with such features as are inherently difficult to master; that is, the piston barrel and the design of the gudgeon pin bearing. Designers of four-stroke engines now-a-days experience approximately the same difficulties, since heat stresses have increased to the point of influencing conditions in the piston barrel. Features which notably affect this are: (a) The material. (b) Prevailing heat conditions.

Exergetic analysis of cogeneration plants through integration of internal combustion engine and process simulators

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Leonardo de Oliveira [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)], E-mail: leonardo.carvalho@petrobras.com.br; Leiroz, Albino Kalab; Cruz, Manuel Ernani [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Programa de Engenharia Mecanica], Emails: leiroz@mecanica.ufrj.br, manuel@mecanica.ufrj.br

2010-07-01

Internal combustion engines (ICEs) have been used in industry and power generation much before they were massively employed for transportation. Their high reliability, excellent power-to-weight ratio, and thermal efficiency have made them a competitive choice as main energy converters in small to medium sized power plants. Process simulators can model ICE powered energy plants with limited depth, due to the highly simplified ICE models used. Usually a better understanding of the global effects of different engine parameters is desirable, since the combustion process within the ICE is typically the main cause of exergy destruction in systems which utilize them. Dedicated commercial ICE simulators have reached such a degree of maturity, that they can adequately model a wide spectrum of phenomena that occur in ICEs. However, ICE simulators are unable to incorporate the remaining of power plant equipment and processes in their models. This paper presents and exploits the integration of an internal combustion engine simulator with a process simulator, so as to evaluate the construction of a fully coupled simulation platform to analyze the performance of ICE-based power plants. A simulation model of an actual cogeneration plant is used as a vehicle for application of the proposed computational methodology. The results show that by manipulating the engine mapping parameters, the overall efficiency of the plant can be improved. (author)

The effect of oil additives on exhaust emission of internal combustion engines

International Nuclear Information System (INIS)

Dimitrovski, M.B.; Kuzmanovski, K.A.

1999-01-01

An attempt was conducted to acquire data on connection between motor oil and motor oil additives and exhaust emission of internal combustion engine. The consulted literature did not contain enough data, so experiments were conducted. The results of the experiments are presented on diagrams that have been processed in the computer program EXCEL. Conclusions that were made out of that work show the need of expanding research on the subject. (Author)

Fuels and Combustion | Transportation Research | NREL

Science.gov (United States)

Fuels and Combustion Fuels and Combustion This is the March 2015 issue of the Transportation and , combustion strategy, and engine design hold the potential to maximize vehicle energy efficiency and performance of low-carbon fuels in internal combustion engines with a whole-systems approach to fuel chemistry

A method and instruments to identify the torque, the power and the efficiency of an internal combustion engine of a wheeled vehicle

Science.gov (United States)

Egorov, A. V.; Kozlov, K. E.; Belogusev, V. N.

2018-01-01

In this paper, we propose a new method and instruments to identify the torque, the power, and the efficiency of internal combustion engines in transient conditions. This method, in contrast to the commonly used non-demounting methods based on inertia and strain gauge dynamometers, allows controlling the main performance parameters of internal combustion engines in transient conditions without inaccuracy connected with the torque loss due to its transfer to the driving wheels, on which the torque is measured with existing methods. In addition, the proposed method is easy to create, and it does not use strain measurement instruments, the application of which does not allow identifying the variable values of the measured parameters with high measurement rate; and therefore the use of them leads to the impossibility of taking into account the actual parameters when engineering the wheeled vehicles. Thus the use of this method can greatly improve the measurement accuracy and reduce costs and laboriousness during testing of internal combustion engines. The results of experiments showed the applicability of the proposed method for identification of the internal combustion engines performance parameters. In this paper, it was determined the most preferred transmission ratio when using the proposed method.

Waste heat recovery systems for internal combustion engines: classification and benefits

OpenAIRE

Marchenko, A.; Samoilenko, D.; Adel Hamzah, Ali; Adel Hamzah, Omar

2014-01-01

Recent trend about the best ways of using the deployable sources of energy in to useful work in order to reduce the rate of consumption of fossil fuel as well as pollution. Out of all the available sources, the internal combustion engines are the major consumer of fossil fuel around the globe. The remaining heat is expelled to the environment through exhaust gases and engine cooling systems, resulting in to entropy rise and serious environmental pollution, so it is required to utilized waste ...

Exhaust gas turbo-charger for internal combustion engines. Abgasturbolader fuer Brennkraftmaschinen

Energy Technology Data Exchange (ETDEWEB)

Behnert, R.

1982-01-07

The invention is concerned with a exhaust gas turbocharger for internal combustion engines. A turbine driving a compressor, is feeded with the exhaust gas. Intended is the over-temperature protection of the exhaust gas turbocharger. For this reason a ring shaped sheet with a well polished nickel surface, serves as thermal shield. A sealing avoids soiling of the turbine shaft. Due to the heat shielding effect no tinder, oxide or dirt deposition is possible. The heat reflection factor is constant.

Stroke prevention in atrial fibrillation: findings from Tuscan FADOI Stroke Registry

Directory of Open Access Journals (Sweden)

Luca Masotti

2014-06-01

Full Text Available Despite vitamin K antagonists (VKAs are considered the first choice treatment for stroke prevention in atrial fibrillation (AF, literature shows their underuse in this context. Since data about VKAs use prior and after acute stroke lack, the aim of this study was to focus on management of anticoagulation with VKAs in this context. Data were retrieved from Tuscan FADOI Stroke Registry, an online data bank aimed to report on characteristics of stroke patients consecutively admitted in Internal Medicine wards in 2010 and 2011. In this period 819 patients with mean age 76.5±12.3 years were enrolled. Data on etiology were available for 715 of them (88.1%, 87% being ischemic and 13% hemorrhagic strokes. AF was present in 238 patients (33%, 165 (69.3% having a known AF before hospitalization, whereas 73 patients (31.7% received a new diagnosis of AF. A percentage of 89% of strokes in patients with known AF were ischemic and 11% hemorrhagic. A percentage of 86.7% of patients with known AF had a CHADS2 ≥2, but only 28.3% were on VKAs before hospitalization. A percentage of 78.8% of patients treated with VKAs before stroke had an international normalized ratio (INR ≤2.0; 68.7% of patients with VKAs-related hemorrhagic strokes had INR ≤3.0. Combined endpoint mortality or severe disability in patients with ischemic stroke associated with AF was present in 47%, while it was present in 19.30% and 19.20% of atherothrombotic and lacunar strokes, respectively. At hospital discharge, VKAs were prescribed in 25.9% of AF related ischemic stroke patients. AF related strokes are burdened by severe outcome but VKAs are dramatically underused in patients with AF, even in higher risk patients. Efforts to improve anticoagulation in this stroke subtype are warranted.

Assessment of disabilities in stroke patients with apraxia : Internal consistency and inter-observer reliability

NARCIS (Netherlands)

van Heugten, CM; Dekker, J; Deelman, BG; Stehmann-Saris, JC; Kinebanian, A

1999-01-01

In this paper the internal consistency and inter-observer reliability of the assessment of disabilities in stroke patients with apraxia is presented. Disabilities were assessed by means of observation of activities of daily living (ADL). The study was conducted at occupational therapy departments in

Assessment of disabilities in stroke patients with apraxia: internal consistency and inter-observer reliability.

NARCIS (Netherlands)

Heugten, C.M. van; Dekker, J.; Deelman, B.G.; Stehmann-Saris, J.C.; Kinebanian, A.

1999-01-01

In this paper the internal consistency and inter-observer reliability of the assessment of disabilities in stroke patients with apraxia is presented. Disabilities were assessed by means of observation of activities of daily living (ADL). The study was conducted at occupational therapy departments in

Experimental investigations on controlled auto-ignition combustion in a four-stroke gasoline engine

OpenAIRE

Oakley, Aaron John

2001-01-01

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The effects of air and exhaust gas dilution on the CAI combustion of a range of fuels including three gasoline compositions, four primary reference fuels, and two alcohols are experimentally investigated using a single cylinder research engine. Two of the three gasolines tested are manufactured from standard gasoline during engine operation by a novel fuel system, designed to improve the per...

Thermodynamic analysis of an in-cylinder waste heat recovery system for internal combustion engines

International Nuclear Information System (INIS)

Zhu, Sipeng; Deng, Kangyao; Qu, Shuan

2014-01-01

In this paper, an in-cylinder waste heat recovery system especially for turbocharged engines is proposed to improve the thermal efficiencies of internal combustion engines. Simplified recovery processes can be described as follows: superheated steam generated by engine waste heat is injected into the pipe before the turbine to increase the boost pressure of the fresh air; intake valve close timing is adjusted to control the amount of fresh air as the original level, and thus the higher pressure charged air expands in the intake stroke and transfers the pressure energy directly to the crankshaft. In this way, the increased turbine output by the pre-turbine steam injection is finally recovered in the cylinder, which is different from the traditional Rankine cycle. The whole energy transfer processes are studied with thermodynamic analyses and numerical simulations. The results show that the mass flow rate of the injected steam has the biggest influence on the energy transfer processes followed by the temperature of the injected steam. With this in-cylinder waste heat recovery system, the fuel economy of a selected turbocharged diesel engine can be improved by 3.2% at the rated operating point when the injected mass flow ratio is set to be 0.1. - Highlights: • An in-cylinder waste heat recovery system is proposed. • Effects of injected parameters are studied with energy and exergy balance theories. • Variations of operating points on the compressor map are studied in detail. • The fuel economy is improved by 3.2% at the rated operating point

Basic characteristics of hospital stroke services in Eastern Hungary

International Nuclear Information System (INIS)

Mihalka, Laszlo; Fekete, Istvan; Csepany, Tuende; Csiba, Laszlo; Bereczki, Daniel

1999-01-01

Stroke mortality is extremely high in Central-Eastern European countries. We report basic characteristics of a stroke unit in Eastern Hungary, including age and sex distribution; the proportion of transient ischemic attacks (TIA), ischemic and hemorrhagic strokes; case fatality; application of diagnostic methods; and length of stay for all patients treated with acute cerebrovascular disease over a 12-month period. Records of all patients with acute cerebrovascular disease (n = 522) discharged in 1995 from a stroke unit with a well defined catchment area of 220,000 inhabitants in Eastern Hungary were retrospectively analyzed. Case fatality was 18.6% for all patients and 21.1% after excluding cases with TIA. Computer tomography, duplex carotid ultrasound, cerebrospinal fluid examination and electroencephalography were performed in 79%, 77%, 7% and 2% of the patients, respectively. The database of the university hospital with the same catchment area was electronically searched for patients who were discharged with the diagnosis of stroke from the three departments of internal medicine. Stroke mortality data of the catchment area based on death certificates was obtained from the Central Statistical Bureau. Two hundred twenty-eight stroke deaths were reported in the catchment area in 1995. In the same period 97 stroke deaths occurred at the stroke unit and 76 at the departments of internal medicine. If we aim to treat all patients with acute stroke at the stroke unit, with the present stroke incidence and duration of hospital stay the current capacity of the stroke unit (1 bed per 10.000 inhabitants) should be doubled

Internal combustion engines fueled by natural gas-hydrogen mixtures

Energy Technology Data Exchange (ETDEWEB)

Akansu, S.O.; Kahraman, N. [Erciyes University, Kayseri (Turkey). Engineering Faculty; Dulger, Z. [Kocaeli University (Turkey). Engineering Faculty; Veziroglu, T.N. [University of Miami, Coral Gables, FL (United States). College of Engineering

2004-11-01

In this study, a survey of research papers on utilization of natural gas-hydrogen mixtures in internal combustion engines is carried out. In general, HC, CO{sub 2}, and CO emissions decrease with increasing H{sub 2}, but NO{sub x} emissions generally increase. If a catalytic converter is used, NO{sub x} emission values can be decreased to extremely low levels. Consequently, equivalence zero emission vehicles (EZEV) standards may be reached. Efficiency values vary with H{sub 2} amount, spark timing, compression ratio, equivalence ratio, etc. Under certain conditions, efficiency values can be increased. In terms of BSFC, emissions and BTE, a mixture of low hydrogen percentage is suitable for using. (author)

A Thermodynamic Analysis of Two Competing Mid-Sized Oxyfuel Combustion Combined Cycles

Directory of Open Access Journals (Sweden)

Egill Thorbergsson

2016-01-01

Full Text Available A comparative analysis of two mid-sized oxyfuel combustion combined cycles is performed. The two cycles are the semiclosed oxyfuel combustion combined cycle (SCOC-CC and the Graz cycle. In addition, a reference cycle was established as the basis for the analysis of the oxyfuel combustion cycles. A parametric study was conducted where the pressure ratio and the turbine entry temperature were varied. The layout and the design of the SCOC-CC are considerably simpler than the Graz cycle while it achieves the same net efficiency as the Graz cycle. The fact that the efficiencies for the two cycles are close to identical differs from previously reported work. Earlier studies have reported around a 3% points advantage in efficiency for the Graz cycle, which is attributed to the use of a second bottoming cycle. This additional feature is omitted to make the two cycles more comparable in terms of complexity. The Graz cycle has substantially lower pressure ratio at the optimum efficiency and has much higher power density for the gas turbine than both the reference cycle and the SCOC-CC.

Stay Focused! The Effects of Internal and External Focus of Attention on Movement Automaticity in Patients with Stroke

Science.gov (United States)

Kal, E. C.; van der Kamp, J.; Houdijk, H.; Groet, E.; van Bennekom, C. A. M.; Scherder, E. J. A.

2015-01-01

Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients’ automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution). Thirty-nine individuals with chronic, unilateral stroke performed a one-leg-stepping task with both legs in single- and dual-task conditions. Attentional focus was manipulated with instructions. Motor performance (movement speed), movement automaticity (fluency of movement), and dual-task performance (dual-task costs) were assessed. The effects of focus on movement speed, single- and dual-task movement fluency, and dual-task costs were analysed with generalized estimating equations. Results showed that, overall, single-task performance was unaffected by focus (p = .341). Regarding movement fluency, no main effects of focus were found in single- or dual-task conditions (p’s ≥ .13). However, focus by leg interactions suggested that an external focus reduced movement fluency of the paretic leg compared to an internal focus (single-task conditions: p = .068; dual-task conditions: p = .084). An external focus also tended to result in inferior dual-task performance (β = -2.38, p = .065). Finally, a near-significant interaction (β = 2.36, p = .055) suggested that dual-task performance was more constrained by patients’ attentional capacity in external focus conditions. We conclude that, compared to an internal focus, an external focus did not result in more automated movements in chronic stroke patients. Contrary to expectations, trends were found for enhanced automaticity with an internal focus. These findings might be due to patients’ strong preference to use an internal focus in daily life. Future work needs to establish the more permanent effects of learning with different attentional foci on re-automating motor

Stay Focused! The Effects of Internal and External Focus of Attention on Movement Automaticity in Patients with Stroke.

Science.gov (United States)

Kal, E C; van der Kamp, J; Houdijk, H; Groet, E; van Bennekom, C A M; Scherder, E J A

2015-01-01

Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients' automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution). Thirty-nine individuals with chronic, unilateral stroke performed a one-leg-stepping task with both legs in single- and dual-task conditions. Attentional focus was manipulated with instructions. Motor performance (movement speed), movement automaticity (fluency of movement), and dual-task performance (dual-task costs) were assessed. The effects of focus on movement speed, single- and dual-task movement fluency, and dual-task costs were analysed with generalized estimating equations. Results showed that, overall, single-task performance was unaffected by focus (p = .341). Regarding movement fluency, no main effects of focus were found in single- or dual-task conditions (p's ≥ .13). However, focus by leg interactions suggested that an external focus reduced movement fluency of the paretic leg compared to an internal focus (single-task conditions: p = .068; dual-task conditions: p = .084). An external focus also tended to result in inferior dual-task performance (β = -2.38, p = .065). Finally, a near-significant interaction (β = 2.36, p = .055) suggested that dual-task performance was more constrained by patients' attentional capacity in external focus conditions. We conclude that, compared to an internal focus, an external focus did not result in more automated movements in chronic stroke patients. Contrary to expectations, trends were found for enhanced automaticity with an internal focus. These findings might be due to patients' strong preference to use an internal focus in daily life. Future work needs to establish the more permanent effects of learning with different attentional foci on re-automating motor control

Control of combustion generated emissions from spark ignition engines: a review

International Nuclear Information System (INIS)

Mansha, M.; Shahid, E.M.; Qureshi, A.H.

2012-01-01

For the past several decades automobiles have been a major source of ground level emissions of various pollutants like CO, HC, NO/sub x/, SO/sub x/ CO/sub 2/, etc. Due to their dangerous effects on human health, vegetation and on climate, various pre combustion, in-cylinder and post. combustion techniques have been tried for their abatement. This paper reviews all of the workable measures taken so far to controlling the combustion generated emissions from 4-stroke Spark Ignition Vehicular Engines ever since the promulgation of emission control legislation/standards and their subsequent enforcement in the late 1960s. (author)

Chemiluminescence analysis of the effect of butanol-diesel fuel blends on the spray-combustion process in an experimental common rail diesel engine

Directory of Open Access Journals (Sweden)

Merola Simona Silvia S.

2015-01-01

Full Text Available Combustion process was studied from the injection until the late combustion phase in an high swirl optically accessible combustion bowl connected to a single cylinder 2-stroke high pressure common rail compression ignition engine. Commercial diesel and blends of diesel and n-butanol (20%: BU20 and 40%: BU40 were used for the experiments. A pilot plus main injection strategy was investigated fixing the injection pressure and fuel mass injected per stroke. Two main injection timings and different pilot-main dwell times were explored achieving for any strategy a mixing controlled combustion. Advancing the main injection start, an increase in net engine working cycle (>40% together with a strong smoke number decrease (>80% and NOx concentration increase (@50% were measured for all pilot injection timings. Compared to diesel fuel, butanol induced a decrease in soot emission and an increase in net engine working area when butanol ratio increased in the blend. A noticeable increase in NOx was detected at the exhaust for BU40 with a slight effect of the dwell-time. Spectroscopic investigations confirmed the delayed auto-ignition (~60 ms of the pilot injection for BU40 compared to diesel. The spectral features for the different fuels were comparable at the start of combustion process, but they evolved in different ways. Broadband signal caused by soot emission, was lower for BU40 than diesel. Different balance of the bands at 309 and 282 nm, due to different OH transitions, were detected between the two fuels. The ratio of these intensities was used to follow flame temperature evolution.

Large Eddy Simulations of Two-phase Turbulent Reactive Flows in IC Engines

Science.gov (United States)

Banaeizadeh, Araz; Schock, Harold; Jaberi, Farhad

2008-11-01

The two-phase filtered mass density function (FMDF) subgrid-scale (SGS) model is used for large-eddy simulation (LES) of turbulent spray combustion in internal combustion (IC) engines. The LES/FMDF is implemented via an efficient, hybrid numerical method. In this method, the filtered compressible Navier-Stokes equations in curvilinear coordinate systems are solved with a generalized, high-order, multi-block, compact differencing scheme. The spray and the FMDF are implemented with Lagrangian methods. The reliability and the consistency of the numerical methods are established for different IC engines and the complex interactions among mean and turbulent velocity fields, fuel droplets and combustion are shown to be well captured with the LES/FMDF. In both spark-ignition/direct-injection and diesel engines, the droplet size and velocity distributions are found to be modified by the unsteady, vortical motions generated by the incoming air during the intake stroke. In turn, the droplets are found to change the in-cylinder flow structure. In the spark-ignition engine, flame propagation is similar to the experiment. In the diesel engine, the maximum evaporated fuel concentration is near the cylinder wall where the flame starts, which is again consistent with the experiment.

Numerical analysis of flow interaction of turbine system in two-stage turbocharger of internal combustion engine

Science.gov (United States)

Liu, Y. B.; Zhuge, W. L.; Zhang, Y. J.; Zhang, S. Y.

2016-05-01

To reach the goal of energy conservation and emission reduction, high intake pressure is needed to meet the demand of high power density and high EGR rate for internal combustion engine. Present power density of diesel engine has reached 90KW/L and intake pressure ratio needed is over 5. Two-stage turbocharging system is an effective way to realize high compression ratio. Because turbocharging system compression work derives from exhaust gas energy. Efficiency of exhaust gas energy influenced by design and matching of turbine system is important to performance of high supercharging engine. Conventional turbine system is assembled by single-stage turbocharger turbines and turbine matching is based on turbine MAP measured on test rig. Flow between turbine system is assumed uniform and value of outlet physical quantities of turbine are regarded as the same as ambient value. However, there are three-dimension flow field distortion and outlet physical quantities value change which will influence performance of turbine system as were demonstrated by some studies. For engine equipped with two-stage turbocharging system, optimization of turbine system design will increase efficiency of exhaust gas energy and thereby increase engine power density. However flow interaction of turbine system will change flow in turbine and influence turbine performance. To recognize the interaction characteristics between high pressure turbine and low pressure turbine, flow in turbine system is modeled and simulated numerically. The calculation results suggested that static pressure field at inlet to low pressure turbine increases back pressure of high pressure turbine, however efficiency of high pressure turbine changes little; distorted velocity field at outlet to high pressure turbine results in swirl at inlet to low pressure turbine. Clockwise swirl results in large negative angle of attack at inlet to rotor which causes flow loss in turbine impeller passages and decreases turbine

Investigation on the Potential of High Efficiency for Internal Combustion Engines

Directory of Open Access Journals (Sweden)

Haifeng Liu

2018-02-01

Full Text Available The current brake thermal efficiency of advanced internal combustion engines is limited to 50%, and how to further improve the efficiency is a challenge. In this study, a theoretical investigation on engine thermal efficiency was carried out using one-dimension simulations based on the first law of thermodynamics. The energy balance was evaluated by varying parameters such as compression ratio (CR; heat transfer coefficient; intake charge properties; and combustion phasing etc.—their influences on the efficiency limits were demonstrated. Results show that for a given heat transfer coefficient, an optimal CR exists to obtain the peak efficiency. The optimal CR decreases with the increase of heat transfer coefficient, and high CR with a low heat-transfer coefficient can achieve a significantly high efficiency. A higher density and specific heat ratio of intake charge, as well as a shorter combustion duration with a proper CA50 (crank angle at 50% of total heat release, can increase efficiency significantly. Methanol shows an excellent ability in decreasing the peak in-cylinder temperature; and the peak indicated efficiency is relatively higher than other tested fuels. The displacement has few effects on the indicated efficiency, while it shows a strong effect on the energy distribution between heat transfer and exhaust energy. All these strategies with high CR result in high in-cylinder pressure and temperature; which means a breakthrough of material is needed in the future.

Post-stroke disposition from a geriatric-rehabilitative stroke care area: an Italian experience

Directory of Open Access Journals (Sweden)

Marco Masina

2014-02-01

Full Text Available A large number of stroke patients cannot be discharged at home. Studies on post stroke disposition have low validity outside the country in which they are carried out because healthcare systems offer different rehabilitative and long-term facilities. Moreover absolute selection criteria for admission to rehabilitation are not available yet. Few studies on post-stroke disposition from Italian stroke units are available. Authors evaluated data of a 18-month period from a geriatric managed stroke care area where comprehensive multi-professional assessment and discharge planning are routinely carried out. Only patients discharged with diagnosis related to acute stroke were considered. Baseline characteristics, clinical, neurological and functional conditions according to the structured multidimensional assessment were prospectively collected in the stroke unit registry. Univariate and multinomial logistic regression were performed to identify independent variables associated with three discharge settings: home, rehabilitation and skilled long-term ward. Out of 188 patients evaluated, 56.4% were discharged home, 18.6% to rehabilitation and 25.0% to long-term ward. Data showed an efficient disposition to intermediate settings with a shorter length of stay compared to other international studies. Factors associated with post-stroke disposition were age, dysphagia, neurological impairment on admission (NIH-SS≥6, after stroke functional status (mRankin≥3, poor pre-stroke functional level (mRankin≥3 and hemorrhagic stroke. Dysphagia, severe neurological impairment and post-stroke disability were associated with discharge to rehabilitation and long term ward. These two settings differed in age and pre-stroke functional condition. Patients discharged to long-term wards were about 10 years older than those admitted to rehabilitative ward. Only 5% of patients discharged to rehabilitation had a pre-stroke mRankin score ≥3. Disposition to a skilled

Validation of a reduced chemical mechanism coupled to CFD model in a 2-stroke HCCI engine

NARCIS (Netherlands)

Izadi Najafabadi, M.; Somers, B.; Nuraini, A.

2015-01-01

Homogeneous Charge Compression Ignition (HCCI) combustion technology has demonstrated a profound potential to decrease both emissions and fuel consumption. In this way, the significance of the 2-stroke HCCI engine has been underestimated as it can provide more power stroke in comparison to a

Accelerated Electromechanical Modeling of a Distributed Internal Combustion Engine Generator Unit

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Serhiy V. Bozhko

2012-07-01

Full Text Available Distributed generation with a combustion engine prime mover is still widely used to supply electric power in a variety of applications. These applications range from backup power supply systems and combined wind-diesel generation to providing power in places where grid connection is either technically impractical or financially uneconomic. Modelling of such systems as a whole is extremely difficult due to the long-time load profiles needed and the computational difficulty of including small time-constant electrical dynamics with large time-constant mechanical dynamics. This paper presents the development of accelerated, reduced-order models of a distributed internal combustions engine generator unit. Overall these models are shown to achieve a massive improvement in the computational time required for long-time simulations while also achieving an extremely high level of dynamic accuracy. It is demonstrated how these models are derived, used and verified against benchmark models created using established techniques. Throughout the paper the modelling set as a whole, including multi level detail, is presented, detailed and finally summarised into a crucial tool for general system investigation and multiple target optimisation.

Recurrence plot for parameters analysing of internal combustion engine

Science.gov (United States)

Alexa, O.; Ilie, C. O.; Marinescu, M.; Vilau, R.; Grosu, D.

2015-11-01

In many technical disciplines modem data analysis techniques has been successfully applied to understand the complexity of the system. The growing volume of theoretical knowledge about systems dynamic's offered researchers the opportunity to look for non-linear dynamics in data whose evolution linear models are unable to explain in a satisfactory manner. One approach in this respect is Recurrence Analysis - RA which is a graphical method designed to locate hidden recurring patterns, nonstationarity and structural changes. RA approach arose in natural sciences like physics and biology but quickly was adopted in economics and engineering. Meanwhile. The fast development of computer resources has provided powerful tools to perform this new and complex model. One free software which was used to perform our analysis is Visual Recurrence Analysis - VRA developed by Eugene Kononov. As is presented in this paper, the recurrence plot investigation for the analyzing of the internal combustion engine shows some of the RPA capabilities in this domain. We chose two specific engine parameters measured in two different tests to perform the RPA. These parameters are injection impulse width and engine angular speed and the tests are I11n and I51n. There were computed graphs for each of them. Graphs were analyzed and compared to obtain a conclusion. This work is an incipient research, being one of the first attempts of using recurrence plot for analyzing automotive dynamics. It opens a wide field of action for future research programs.

Influence of distillation on performance, emission, and combustion of a DI diesel engine, using tyre pyrolysis oil diesel blends

Directory of Open Access Journals (Sweden)

Murugan Sivalingam

2008-01-01

Full Text Available Conversion of waste to energy is one of the recent trends in minimizing not only the waste disposal but also could be used as an alternate fuel for internal combustion engines. Fuels like wood pyrolysis oil, rubber pyrolysis oil are also derived through waste to energy conversion method. Early investigations report that tyre pyrolysis oil derived from vacuum pyrolysis method seemed to possess properties similar to diesel fuel. In the present work, the crude tyre pyrolisis oil was desulphurised and distilled to improve the properties and studied the use of it. Experimental studies were conducted on a single cylinder four-stroke air cooled engine fuelled with two different blends, 30% tyre pyrolysis oil and 70% diesel fuel (TPO 30 and 30% distilled tyre pyrolysis oil and 70% diesel fuel (DTPO 30. The results of the performance, emission and combustion characteristics of the engine indicated that NOx is reduced by about 8% compared to tire pyrolysis oil and by about 10% compared to diesel fuel. Hydrocarbon emission is reduced by about 2% compared to TPO 30 operation. Smoke increased for DTPO 30 compared to TPO 30 and diesel fuel.

Observer reliability of CT angiography in the assessment of acute ischaemic stroke: data from the Third International Stroke Trial

International Nuclear Information System (INIS)

Mair, Grant; Farrall, Andrew J.; Sellar, Robin J.; Mollison, Daisy; Sakka, Eleni; Palmer, Jeb; Wardlaw, Joanna M.; Kummer, Ruediger von; Adami, Alessandro; White, Philip M.; Adams, Matthew E.; Yan, Bernard; Demchuk, Andrew M.; Ramaswamy, Rajesh; Rodrigues, Mark A.; Samji, Karim; Baird, Andrew J.; Boyd, Elena V.; Cohen, Geoff; Perry, David; Sandercock, Peter A.G.; Lindley, Richard

2015-01-01

CT angiography (CTA) is often used for assessing patients with acute ischaemic stroke. Only limited observer reliability data exist. We tested inter- and intra-observer reliability for the assessment of CTA in acute ischaemic stroke. We selected 15 cases from the Third International Stroke Trial (IST-3, ISRCTN25765518) with various degrees of arterial obstruction in different intracranial locations on CTA. To assess inter-observer reliability, seven members of the IST-3 expert image reading panel (>5 years experience reading CTA) and seven radiology trainees (<2 years experience) rated all 15 scans independently and blind to clinical data for: presence (versus absence) of any intracranial arterial abnormality (stenosis or occlusion), severity of arterial abnormality using relevant scales (IST-3 angiography score, Thrombolysis in Cerebral Infarction (TICI) score, Clot Burden Score), collateral supply and visibility of a perfusion defect on CTA source images (CTA-SI). Intra-observer reliability was assessed using independently repeated expert panel scan ratings. We assessed observer agreement with Krippendorff's-alpha (K-alpha). Among experienced observers, inter-observer agreement was substantial for the identification of any angiographic abnormality (K-alpha = 0.70) and with an angiography assessment scale (K-alpha = 0.60-0.66). There was less agreement for grades of collateral supply (K-alpha = 0.56) or for identification of a perfusion defect on CTA-SI (K-alpha = 0.32). Radiology trainees performed as well as expert readers when additional training was undertaken (neuroradiology specialist trainees). Intra-observer agreement among experts provided similar results (K-alpha = 0.33-0.72). For most imaging characteristics assessed, CTA has moderate to substantial observer agreement in acute ischaemic stroke. Experienced readers and those with specialist training perform best. (orig.)

IEA combustion agreement : a collaborative task on alternative fuels in combustion

International Nuclear Information System (INIS)

Larmi, M.

2009-01-01

The focus of the alternative fuels in combustion task of the International Energy Agency is on high efficiency engine combustion, furnace combustion, and combustion chemistry. The objectives of the task are to develop optimum combustion for dedicated fuels by fully utilizing the physical and chemical properties of synthetic and renewable fuels; a significant reduction in carbon dioxide, NOx and particulate matter emissions; determine the minimum emission levels for dedicated fuels; and meet future emission standards of engines without or with minimum after-treatment. This presentation discussed the alternative fuels task and addressed issues such as synthetic fuel properties and benefits. The anticipated future roadmap was presented along with a list of the synthetic and renewable engine fuels to be studied, such as neat oxygenates like alcohols and ethers, biogas/methane and gas combustion, fuel blends, dual fuel combustion, high cetane number diesel fuels like synthetic Fischer-Tropsch diesel fuel and hydrogenated vegetable oil, and low CN number fuels. Implementation examples were also discussed, such as fuel spray studies in optical spray bombs; combustion research in optical engines and combustion chambers; studies on reaction kinetics of combustion and emission formation; studies on fuel properties and ignition behaviour; combustion studies on research engines; combustion optimization; implementing the optimum combustion in research engines; and emission measurements. Overall milestone examples and the overall schedule of participating countries were also presented. figs.

Design and simulation of a two- or four-stroke free-piston engine generator for range extender applications

International Nuclear Information System (INIS)

Jia, Boru; Smallbone, Andrew; Zuo, Zhengxing; Feng, Huihua; Roskilly, Anthony Paul

2016-01-01

Highlights: • A FPE model operated in two thermodynamic cycles is presented. • The engine performance for both gas exchange cycles are described. • Power distribution with different operation parameters are provided. • Advantages and disadvantages for the two thermodynamic cycles are summarised. - Abstract: Free-piston engines (FPEs) are known to have a greater thermal efficiency (40–50%) than an equivalent and more conventional four-stroke reciprocating engines (30–40%). Modern FPEs are proposed for the generation of electric and hydraulic power, with a potential application in hybrid electric vehicles. The numerous FPE configurations considered to date have almost exclusively operated using a two-stroke thermodynamic cycle to improve the thermal efficiency, however it is well known that the application of two-stoke cycles can be limited by noise and exhaust gas emissions constraints. In this article, a numerical model is used to investigate the techno-feasibility of operating Newcastle University’s FPE prototype using a two- or four-stroke thermodynamic cycle. If operated as a four-stroke cycle, the linear generator must be used as both a motor and a generator resulting in a more irregular piston motion compared to corresponding operating in a two-stroke cycle. In four-stroke cycles, almost half the indicated power is consumed in overcoming the pumping losses of the motoring process. Whilst the heat release process is appears to be closer to a constant volume process when operated on two-stroke engine cycle, the peak cylinder pressure and compression ratio proved lower. In addition, a narrower power range is reported for a four-stroke cycle despite a corresponding higher thermal efficiency.

Internal combustion engine with rotary valve assembly having variable intake valve timing

Science.gov (United States)

Hansen, Craig N.; Cross, Paul C.

1995-01-01

An internal combustion engine has rotary valves associated with movable shutters operable to vary the closing of intake air/fuel port sections to obtain peak volumetric efficiency over the entire range of speed of the engine. The shutters are moved automatically by a control mechanism that is responsive to the RPM of the engine. A foot-operated lever associated with the control mechanism is also used to move the shutters between their open and closed positions.

Disturbing effect of free hydrogen on fuel combustion in internal combustion engines

Science.gov (United States)

Riedler, A

1923-01-01

Experiments with fuel mixtures of varying composition, have recently been conducted by the Motor Vehicle and Airplane Engine Testing Laboratories of the Royal Technical High School in Berlin and at Fort Hahneberg, as well as at numerous private engine works. The behavior of hydrogen during combustion in engines and its harmful effect under certain conditions, on the combustion in the engine cylinder are of general interest. Some of the results of these experiments are given here, in order to elucidate the main facts and explain much that is already a matter of experience with chauffeurs and pilots.

Prediction of Large Vessel Occlusions in Acute Stroke: National Institute of Health Stroke Scale Is Hard to Beat.

Science.gov (United States)

Vanacker, Peter; Heldner, Mirjam R; Amiguet, Michael; Faouzi, Mohamed; Cras, Patrick; Ntaios, George; Arnold, Marcel; Mattle, Heinrich P; Gralla, Jan; Fischer, Urs; Michel, Patrik

2016-06-01

Endovascular treatment for acute ischemic stroke with a large vessel occlusion was recently shown to be effective. We aimed to develop a score capable of predicting large vessel occlusion eligible for endovascular treatment in the early hospital management. Retrospective, cohort study. Two tertiary, Swiss stroke centers. Consecutive acute ischemic stroke patients (1,645 patients; Acute STroke Registry and Analysis of Lausanne registry), who had CT angiography within 6 and 12 hours of symptom onset, were categorized according to the occlusion site. Demographic and clinical information was used in logistic regression analysis to derive predictors of large vessel occlusion (defined as intracranial carotid, basilar, and M1 segment of middle cerebral artery occlusions). Based on logistic regression coefficients, an integer score was created and validated internally and externally (848 patients; Bernese Stroke Registry). None. Large vessel occlusions were present in 316 patients (21%) in the derivation and 566 (28%) in the external validation cohort. Five predictors added significantly to the score: National Institute of Health Stroke Scale at admission, hemineglect, female sex, atrial fibrillation, and no history of stroke and prestroke handicap (modified Rankin Scale score, < 2). Diagnostic accuracy in internal and external validation cohorts was excellent (area under the receiver operating characteristic curve, 0.84 both). The score performed slightly better than National Institute of Health Stroke Scale alone regarding prediction error (Wilcoxon signed rank test, p < 0.001) and regarding discriminatory power in derivation and pooled cohorts (area under the receiver operating characteristic curve, 0.81 vs 0.80; DeLong test, p = 0.02). Our score accurately predicts the presence of emergent large vessel occlusions, which are eligible for endovascular treatment. However, incorporation of additional demographic and historical information available on hospital arrival

A novel split cycle internal combustion engine with integral waste heat recovery

International Nuclear Information System (INIS)

Dong, Guangyu; Morgan, Robert; Heikal, Morgan

2015-01-01

Highlights: • A novel engine thermodynamic cycle is proposed. • Theoretical analysis is applied to identify the key parameters of the thermodynamic cycle. • The key stages of the split cycle are analysed via one-dimensional modelling work. • The effecting mechanism of the split cycle efficiency is analysed. - Abstract: To achieve a step improvement in engine efficiency, a novel split cycle engine concept is proposed. The engine has separate compression and combustion cylinders and waste heat is recovered between the two. Quasi-isothermal compression of the charge air is realised in the compression cylinder while isobaric combustion of the air/fuel mixture is achieved in the combustion cylinder. Exhaust heat recovery between the compression and combustion chamber enables highly efficient recovery of waste heat within the cycle. Based on cycle analysis and a one-dimensional engine model, the fundamentals and the performance of the split thermodynamic cycle is estimated. Compared to conventional engines, the compression work can be significantly reduced through the injection of a controlled quantity of water in the compression cylinder, lowering the gas temperature during compression. Thermal energy can then be effectively recovered from the engine exhaust in a recuperator between the cooled compressor cylinder discharge air and the exhaust gas. The resulting hot high pressure air is then injected into a combustor cylinder and mixed with fuel, where near isobaric combustion leads to a low combustion temperature and reduced heat transferred from the cylinder wall. Detailed cycle simulation indicates a 32% efficiency improvement can be expected compared to the conventional diesel engines.

Impact of higher n-butanol addition on combustion and performance of GDI engine in stoichiometric combustion

International Nuclear Information System (INIS)

Chen, Zheng; Yang, Feng; Xue, Shuo; Wu, Zhenkuo; Liu, Jingping

2015-01-01

Highlights: • Effects of 0–50% n-butanol addition on GDI engine are experimentally studied. • Higher n-butanol fractions increase combustion pressure and fasten burning rate. • Higher n-butanol fractions increase BSFC but improve BTE. • Higher n-butanol fractions enhance combustion stability but increase knock intensity. • Higher n-butanol fractions reduce exhaust temperature and NOx emissions. - Abstract: An experimental study was carried out on a turbocharged gasoline direct injection (GDI) engine fueled by n-butanol/gasoline blends. Effects of n-butanol percents (15%, 30%, and 50%) on combustion and performance of the engine operating on stoichiometric combustion condition were discussed and also compared with pure gasoline in this paper. The results indicate that n-butanol/gasoline blends increase combustion pressure and pressure rise rate, fasten burning rate, and shorten ignition delay and combustion duration, as compared to pure gasoline. Moreover, these trends are impacted more evidently with increased n-butanol fraction in the blends. In addition, higher n-butanol percent of gasoline blends increase combustion temperature but decrease the temperature in the later stage of expansion stroke, which contributes to the control of exhaust temperature at high-load. With regards to engine performance, higher n-butanol percent in the blends results in increased brake specific fuel consumption (BSFC) and higher brake thermal efficiency (BTE). However, higher n-butanol addition helps to improve combustion stability but shows slightly higher knock possibility in high-load. In that case, the knock trend could be weakened by retarding ignition timing. Moreover, higher n-butanol addition significantly decreases NOx emissions, but it increases CO emissions obviously.

Development of pressurized internally circulating fluidized bed combustion technology; Kaatsu naibu junkan ryudosho boiler no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

Ishihara, I [Center for Coal Utilization, Japan, Tokyo (Japan); Nagato, S; Toyoda, S [Ebara Corp., Tokyo (Japan)

1996-09-01

The paper introduced support research on element technology needed for the design of hot models of the pressurized internally circulating fluidized bed combustion boiler in fiscal 1995 and specifications for testing facilities of 4MWt hot models after finishing the basic plan. The support research was conduced as follows: (a) In the test for analysis of cold model fluidization, it was confirmed that each characteristic value of hot models is higher than the target value. Further, calculation parameters required for computer simulation were measured and data on the design of air diffusion nozzle for 1 chamber wind box were sampled. (b) In the CWP conveyance characteristic survey, it was confirmed that it is possible to produce CWP having favorable properties. It was also confirmed that favorable conveyability can be maintained even if the piping size was reduced down to 25A. (c) In the gas pressure reducing test, basic data required for the design of gas pressure reducing equipment were sampled. Specifications for the fluidized bed combustion boiler of hot models are as follows: evaporation amount: 3070kg/h, steam pressure: 1.77MPa, fuel supply amount: 600kg-coal/h, boiler body: cylinder shape water tube internally circulating fluidized bed combustion boiler. 4 refs., 4 figs.

Particular mechanism for continuously varying the compression ratio for an internal combustion engine

Science.gov (United States)

Raţiu, S.; Cătălinoiu, R.; Alexa, V.; Miklos, I.; Cioată, V.

2018-01-01

Variable compression ratio (VCR) is a technology to adjust the compression ratio of an internal combustion engine while the engine is in operation. The paper proposes the presentation of a particular mechanism allowing the position of the top dead centre to be changed, while the position of the bottom dead centre remains fixed. The kinematics of the mechanism is studied and its trajectories are graphically represented for different positions of operation.

Internal combustion engine cold-start efficiency: A review of the problem, causes and potential solutions

International Nuclear Information System (INIS)

Roberts, Andrew; Brooks, Richard; Shipway, Philip

2014-01-01

Highlights: • The sources of I.C. engine cold start efficiency are reviewed and quantified. • Potential solutions are reviewed and the benefit quantified together. • Potential conflicts between different engine sub-systems are discussed. • Fuel consumption benefits of up to 7% are observed during cold start. • Emission reductions of up to 40% during cold start are observed. - Abstract: Legislation on vehicle emissions continues to become more stringent in an effort to minimise the impact of internal combustion engines on the environment. One area of significant concern in this respect is that of the cold-start; the thermal efficiency of the internal combustion engine is significantly lower at cold-start than when the vehicle reaches steady state temperatures owing to sub-optimal lubricant and component temperatures. The drive for thermal efficiency (of both the internal combustion engine and of the vehicle as a whole) has led to a variety of solutions being trialled to assess their merits and effects on other vehicle systems during this warm-up phase (and implemented where appropriate). The approaches have a common theme of attempting to reduce energy losses so that systems and components reach their intended operating temperature range as soon as possible after engine start. In the case of the engine, this is primarily focused on the lubricant system. Lubricant viscosity is highly sensitive to temperature and the increased viscosity at low temperatures results in higher frictional and pumping losses than would be observed at the target operating temperature. The approaches used to tackle the problem include the use of phase change materials (to reduce the cool-down rate during a period following engine running) [1,2] and the use of thermal barrier coatings in an attempt to insulate the cylinder bore and prevent heat loss (thus increasing the amount of energy utilised as brake work [3]). A range of system alterations have also been trialled including

Free-piston engine

Science.gov (United States)

Van Blarigan, Peter

2001-01-01

A combustion system which can utilize high compression ratios, short burn durations, and homogeneous fuel/air mixtures in conjunction with low equivalence ratios. In particular, a free-piston, two-stroke autoignition internal combustion engine including an electrical generator having a linear alternator with a double-ended free piston that oscillates inside a closed cylinder is provided. Fuel and air are introduced in a two-stroke cycle fashion on each end, where the cylinder charge is compressed to the point of autoignition without spark plugs. The piston is driven in an oscillating motion as combustion occurs successively on each end. This leads to rapid combustion at almost constant volume for any fuel/air equivalence ratio mixture at very high compression ratios. The engine is characterized by high thermal efficiency and low NO.sub.x emissions. The engine is particularly suited for generating electrical current in a hybrid automobile.

Biomass-based gasifiers for internal combustion (IC) engines—A ...

Indian Academy of Sciences (India)

biomass is converted into a combustible producer gas. ..... with gasification efficiency, increased with the increase in gas flow rate. .... Livingston W R 2007 Report on Biomass ash characteristics and behaviour in combustion, gasification.

COMBUSTION AND PERFORMANCE CHARACTERISTICS OF A SMALL SPARK IGNITION ENGINE FUELLED WITH HCNG

Directory of Open Access Journals (Sweden)

A. SONTHALIA

2015-04-01

Full Text Available Due to environmental concerns and fossil fuel depletion, large scale researches were carried out involving the use of natural gas in internal combustion engines. Natural gas is a clean burning fuel that is available from large domestic natural reserve. When it is used as a fuel in SI engines, it reduces emissions to meet EURO-III norms with carburettors and EURO-IV norms with manifold injection. Countries like India with fewer natural fossil fuel reserves depend heavily on oil imported from Middle East Asian countries and on the other hand combustion of fossil fuel has negative impact on air quality in urban areas. Use of CNG as a fuel in internal combustion engines can reduce the intensiveness of these pervasive problems. The performance of CNG can further be improved by addition of small percentages of hydrogen to it to overcome the drawbacks like lower energy density of the fuel, drop in engine power and engine out exhaust emissions. When hydrogen is added to CNG it is called as Hythane or Hydrogen enriched Compressed Natural Gas (HCNG. This can be considered as a first step towards promotion of hydrogen in automobiles. In this study, the effects of mixing hydrogen with CNG on a small air cooled four stroke SI engine’s performance, emissions and heat release rate was analyzed. A comparison of performance and emission by running engine separately on gasoline, hydrogen, CNG and HCNG was done. The results show a significant decrease in HC, CO and NOx emissions and marginal increase in specific energy consumption when fuelled with HCNG.

Analysis of two different types of hydrogen combustion during severe accidents in a typical pressurized water reactor

International Nuclear Information System (INIS)

Ko Yuchih; Lee Min

2005-01-01

Hydrogen combustion is an important phenomenon that may occur during severe accidents of Nuclear Power Plants (NPPs). Depending on the specific plant design, the initiating events, and mitigation actions executed, hydrogen combustion may have distinct characteristics and may damage the plant in various degrees. The worst scenario will be the catastrophic failure of containment. In this study two specific types of hydrogen combustion are analyzed to evaluate their impact on the containment integrity. In this paper, Station Blackout (SBO) and Loss of Coolant Accidents (LOCAs) sequences are analyzed using MAAP4 (Modular Accident Analysis Program) code. The former sequence is used to represent hydrogen combustion phenomenon under the condition that the reactor pressure vessel (RPV) breaches at high pressure and the latter sequence represents the phenomenon that RPV fails at low pressure. Two types of hydrogen combustion are observed in the simulation. The Type I hydrogen combustion represents global and instantaneous hydrogen combustion. Large pressure spike is created during the combustion and represents a threat to containment integrity. Type II hydrogen combustion is localized burn and burn continuously over a time period. There is hardly any impact of this type hydrogen burn on the containment pressurization rate. Both types of hydrogen combustion can occur in the severe accidents without any human intervention. From the accident mitigation point of view, operators should try to bring the containment into conditions that favor the Type II hydrogen combustion. (authors)

Impact of the injection dose of exhaust gases, on work parameters of combustion engine

Science.gov (United States)

Marek, W.; Śliwiński, K.

2016-09-01

This article is another one from the series in which were presented research results indicated the possible areas of application of the pneumatic injection using hot combustion gases proposed by Professor Jarnuszkiewicz. This publication present the results of the control system of exhaust gas recirculation. The main aim of this research was to determine the effect of exhaust gas recirculation to the operating parameters of the internal combustion engine on the basis of laboratory measurements. All measurements were performed at a constant engine speed. These conditions correspond to the operation of the motor operating an electrical generator. The study was conducted on the four-stroke two-cylinder engine with spark ignition. The study were specifically tested on the air injection system and therefore the selection of the rotational speed was not bound, as in conventional versions of operating parameters of the electrical machine. During the measurement there were applied criterion which used power control corresponding to the requirements of load power, at minimal values of engine speed. Recirculation value determined by the following recurrent position control valve of the injection doses inflator gas for pneumatic injection system. They were studied and recorded, the impact of dose of gases recirculation to the operating and ecological engine parameters such as power, torque, specific fuel consumption, efficiency, air fuel ratio, exhaust gas temperature and nitrogen oxides and hydrocarbons.

A comparison between EGR and lean-burn strategies employed in a natural gas SI engine using a two-zone combustion model

Energy Technology Data Exchange (ETDEWEB)

Ibrahim, Amr; Bari, Saiful [Sustainable Energy Centre, School of Advanced Manufacturing and Mechanical Engineering, Univ. of South Australia, Mawson Lakes SA 5095 (Australia)

2009-12-15

Exhaust gas recirculation (EGR) strategy has been recently employed in natural gas SI engines as an alternative to lean burn technique in order to satisfy the increasingly stringent emission standards. However, the effect of EGR on some of engine performance parameters compared to lean burn is not yet quite certain. In the current study, the effect of both EGR and lean burn on natural gas SI engine performance was compared at similar operating conditions. This was achieved numerically by developing a computer simulation of the four-stroke spark-ignition natural gas engine. A two-zone combustion model was developed to simulate the in-cylinder conditions during combustion. A kinetic model based on the extended Zeldovich mechanism was also developed in order to predict NO emission. The combustion model was validated using experimental data and a good agreement between the results was found. It was demonstrated that adding EGR to the stoichiometric inlet charge at constant inlet pressure of 130 kPa decreased power more rapidly than excess air; however, the power loss was recovered by increasing the inlet pressure from 130 kPa at zero dilution to 150 kPa at 20% EGR dilution. The engine fuel consumption increased by 10% when 20% EGR dilution was added at inlet pressure of 150 kPa compared to using 20% air dilution at 130 kPa. However, it was found that EGR dilution strategy is capable of producing extremely lower NO emission than lean burn technique. NO emission was reduced by about 70% when the inlet charge was diluted at a rate of 20% using EGR instead of excess air. (author)

A comparison between EGR and lean-burn strategies employed in a natural gas SI engine using a two-zone combustion model

International Nuclear Information System (INIS)

Ibrahim, Amr; Bari, Saiful

2009-01-01

Exhaust gas recirculation (EGR) strategy has been recently employed in natural gas SI engines as an alternative to lean burn technique in order to satisfy the increasingly stringent emission standards. However, the effect of EGR on some of engine performance parameters compared to lean burn is not yet quite certain. In the current study, the effect of both EGR and lean burn on natural gas SI engine performance was compared at similar operating conditions. This was achieved numerically by developing a computer simulation of the four-stroke spark-ignition natural gas engine. A two-zone combustion model was developed to simulate the in-cylinder conditions during combustion. A kinetic model based on the extended Zeldovich mechanism was also developed in order to predict NO emission. The combustion model was validated using experimental data and a good agreement between the results was found. It was demonstrated that adding EGR to the stoichiometric inlet charge at constant inlet pressure of 130 kPa decreased power more rapidly than excess air; however, the power loss was recovered by increasing the inlet pressure from 130 kPa at zero dilution to 150 kPa at 20% EGR dilution. The engine fuel consumption increased by 10% when 20% EGR dilution was added at inlet pressure of 150 kPa compared to using 20% air dilution at 130 kPa. However, it was found that EGR dilution strategy is capable of producing extremely lower NO emission than lean burn technique. NO emission was reduced by about 70% when the inlet charge was diluted at a rate of 20% using EGR instead of excess air.

Validation of a zero-dimensional model for prediction of NOx and engine performance for electronically controlled marine two-stroke diesel engines

International Nuclear Information System (INIS)

Scappin, Fabio; Stefansson, Sigurður H.; Haglind, Fredrik; Andreasen, Anders; Larsen, Ulrik

2012-01-01

The aim of this paper is to derive a methodology suitable for energy system analysis for predicting the performance and NO x emissions of marine low speed diesel engines. The paper describes a zero-dimensional model, evaluating the engine performance by means of an energy balance and a two zone combustion model using ideal gas law equations over a complete crank cycle. The combustion process is divided into intervals, and the product composition and flame temperature are calculated in each interval. The NO x emissions are predicted using the extended Zeldovich mechanism. The model is validated using experimental data from two MAN B and W engines; one case being data subject to engine parameter changes corresponding to simulating an electronically controlled engine; the second case providing data covering almost all model input and output parameters. The first case of validation suggests that the model can predict specific fuel oil consumption and NO x emissions within the 95% confidence intervals given by the experimental measurements. The second validation confirms the capability of the model to match measured engine output parameters based on measured engine input parameters with a maximum 5% deviation. - Highlights: ► A fast realistic model of a marine two-stroke low speed diesel engine was derived. ► The model is fast and accurate enough for future complex energy systems analysis. ► The effects of engine tuning were validated with experimental tests. ► The model was validated while constrained by experimental input and output data.

Comparison of catalytic converter performance in internal combustion engine fueled with Ron 95 and Ron 97 gasoline

Science.gov (United States)

Leman, A. M.; Rahman, Fakhrurrazi; Jajuli, Afiqah; Feriyanto, Dafit; Zakaria, Supaat

2017-09-01

Generating ideal stability between engine performance, fuel consumption and emission is one of the main challenges in the automotive industry. The characteristics of engine combustion and creation of emission might simply change with different types of operating parameters. This study aims in investigating the relationship between two types of fuels on the performance and exhaust emission of internal combustion engine using ceramic and metallic catalytic converters. Experimental tests were performed on Mitsubishi 4G93 engine by applying several ranges of engine speeds to determine the conversion of pollutant gases released by the engine. The obtained results specify that the usage of RON 97 equipped with metallic converters might increase the conversion percentage of 1.31% for CO and 126 ppm of HC gases. The metallic converters can perform higher conversion compared to ceramic because in the high space velocities, metallic has higher surface geometry area and higher amount of transverse Peclet number (Pi). Ceramic converters achieved conversion at 2496 ppm of NOx gas, which is higher than the metallic converter.

Observer reliability of CT angiography in the assessment of acute ischaemic stroke: data from the Third International Stroke Trial

Energy Technology Data Exchange (ETDEWEB)

Mair, Grant; Farrall, Andrew J.; Sellar, Robin J.; Mollison, Daisy; Sakka, Eleni; Palmer, Jeb; Wardlaw, Joanna M. [University of Edinburgh, Western General Hospital, Division of Neuroimaging Sciences, Edinburgh (United Kingdom); Kummer, Ruediger von [Dresden University Stroke Centre, University Hospital, Department of Neuroradiology, Dresden (Germany); Adami, Alessandro [Sacro Cuore-Don Calabria Hospital, Stroke Center, Department of Neurology, Negrar (Italy); White, Philip M. [Stroke Research Group, Newcastle upon Tyne (United Kingdom); Adams, Matthew E. [National Hospital for Neurology and Neurosurgery, Department of Neuroradiology, London (United Kingdom); Yan, Bernard [Royal Melbourne Hospital, Neurovascular Research Group, Parkville (Australia); Demchuk, Andrew M. [Calgary Stroke Program, Department of Clinical Neurosciences, Calgary (Canada); Ramaswamy, Rajesh; Rodrigues, Mark A.; Samji, Karim; Baird, Andrew J. [Royal Infirmary of Edinburgh, Department of Radiology, Edinburgh (United Kingdom); Boyd, Elena V. [Northwick Park Hospital, Department of Radiology, Harrow (United Kingdom); Cohen, Geoff; Perry, David; Sandercock, Peter A.G. [University of Edinburgh, Western General Hospital, Division of Clinical Neurosciences, Edinburgh (United Kingdom); Lindley, Richard [University of Sydney, Westmead Hospital Clinical School and The George Institute for Global Health, Sydney (Australia); Collaboration: The IST-3 Collaborative Group

2014-10-07

CT angiography (CTA) is often used for assessing patients with acute ischaemic stroke. Only limited observer reliability data exist. We tested inter- and intra-observer reliability for the assessment of CTA in acute ischaemic stroke. We selected 15 cases from the Third International Stroke Trial (IST-3, ISRCTN25765518) with various degrees of arterial obstruction in different intracranial locations on CTA. To assess inter-observer reliability, seven members of the IST-3 expert image reading panel (>5 years experience reading CTA) and seven radiology trainees (<2 years experience) rated all 15 scans independently and blind to clinical data for: presence (versus absence) of any intracranial arterial abnormality (stenosis or occlusion), severity of arterial abnormality using relevant scales (IST-3 angiography score, Thrombolysis in Cerebral Infarction (TICI) score, Clot Burden Score), collateral supply and visibility of a perfusion defect on CTA source images (CTA-SI). Intra-observer reliability was assessed using independently repeated expert panel scan ratings. We assessed observer agreement with Krippendorff's-alpha (K-alpha). Among experienced observers, inter-observer agreement was substantial for the identification of any angiographic abnormality (K-alpha = 0.70) and with an angiography assessment scale (K-alpha = 0.60-0.66). There was less agreement for grades of collateral supply (K-alpha = 0.56) or for identification of a perfusion defect on CTA-SI (K-alpha = 0.32). Radiology trainees performed as well as expert readers when additional training was undertaken (neuroradiology specialist trainees). Intra-observer agreement among experts provided similar results (K-alpha = 0.33-0.72). For most imaging characteristics assessed, CTA has moderate to substantial observer agreement in acute ischaemic stroke. Experienced readers and those with specialist training perform best. (orig.)

Translating knowledge for action against stroke--using 5-minute videos for stroke survivors and caregivers to improve post-stroke outcomes: study protocol for a randomized controlled trial (Movies4Stroke).

Science.gov (United States)

Kamal, Ayeesha Kamran; Khoja, Adeel; Usmani, Bushra; Muqeet, Abdul; Zaidi, Fabiha; Ahmed, Masood; Shakeel, Saadia; Soomro, Nabila; Gowani, Ambreen; Asad, Nargis; Ahmed, Asma; Sayani, Saleem; Azam, Iqbal; Saleem, Sarah

2016-01-27

Two thirds of the global mortality of stroke is borne by low and middle income countries (LMICs). Pakistan is the world's sixth most populous country with a stroke-vulnerable population and is without a single dedicated chronic care center. In order to provide evidence for a viable solution responsive to this health care gap, and leveraging the existing >70% mobile phone density, we thought it rational to test the effectiveness of a mobile phone-based video intervention of short 5-minute movies to educate and support stroke survivors and their primary caregivers. Movies4Stroke will be a randomized control, outcome assessor blinded, parallel group, single center superiority trial. Participants with an acute stroke, medically stable, with mild to moderate disability and having a stable primary caregiver will be included. After obtaining informed consent the stroke survivor-caregiver dyad will be randomized. Intervention participants will have the movie program software installed in their phone, desktop, or Android device which will allow them to receive, view and repeat 5-minute videos on stroke-related topics at admission, discharge and first and third months after enrollment. The control arm will receive standard of care at an internationally accredited center with defined protocols. The primary outcome measure is medication adherence as ascertained by a locally validated Morisky Medication Adherence Scale and control of major risk factors such as blood pressure, blood sugar and blood cholesterol at 12 months post discharge. Secondary outcome measures are post-stroke complications and mortality, caregiver knowledge and change in functional outcomes after acute stroke at 1, 3, 6, 9 and 12 months. Movies4Stroke is designed to enroll 300 participant dyads after inflating 10% to incorporate attrition and non-compliance and has been powered at 95% to detect a 15% difference between intervention and usual care arm. Analysis will be done by the intention

From orbital debris capture systems through internal combustion engines on Mars

Science.gov (United States)

1991-01-01

The investigation and conceptualization of an orbital debris collector was the primary area of design. In addition, an alternate structural design for Space Station Freedom and systems supporting resource utilization at Mars and the moon were studied. Hardware for production of oxygen from simulate Mars atmosphere was modified to permit more reliable operation at low pressures (down to 10 mb). An internal combustion engine was altered to study how Mars atmosphere could be used as a diluent to control combustion temperatures and avoid excess Mars propellant production requirements that would result from either methane-rich or oxygen-rich, methane-oxygen combustion. An elastic loop traction system that could be used for lunar construction vehicles was refined to permit testing. A parabolic heat rejection radiator system was designed and built to determine whether it was capable of increasing heat rejection rates during lunar daytime operation. In addition, an alternate space station truss design, utilizing a pre-integrated concept, was studied and found to reduce estimate extravehicular activity (EVA) time and increase the structural integrity when compared to the original Warren truss concept. An orbital-debris-capturing spacecraft design which could be mated with the Orbital Maneuvering Vehicle was studied. The design identified Soviet C-1B boosters as the best targets of opportunity in Earth orbits between an altitude of 900 km and 1100 km and at an inclination of 82.9 deg. A dual robot pallet, which could be spun to match the tumbling rate of the C-1B booster, was developed as the conceptual design.

Breaststroke swimmers moderate internal work increases toward the highest stroke frequencies.

Science.gov (United States)

Lauer, Jessy; Olstad, Bjørn Harald; Minetti, Alberto Enrico; Kjendlie, Per-Ludvik; Rouard, Annie Hélène

2015-09-18

A model to predict the mechanical internal work of breaststroke swimming was designed. It allowed us to explore the frequency-internal work relationship in aquatic locomotion. Its accuracy was checked against internal work values calculated from kinematic sequences of eight participants swimming at three different self-chosen paces. Model predictions closely matched experimental data (0.58 ± 0.07 vs 0.59 ± 0.05 J kg(-1)m(-1); t(23)=-0.30, P=0.77), which was reflected in a slope of the major axis regression between measured and predicted total internal work whose 95% confidence intervals included the value of 1 (β=0.84, [0.61, 1.07], N=24). The model shed light on swimmers ability to moderate the increase in internal work at high stroke frequencies. This strategy of energy minimization has never been observed before in humans, but is present in quadrupedal and octopedal animal locomotion. This was achieved through a reduced angular excursion of the heaviest segments (7.2 ± 2.9° and 3.6 ± 1.5° for the thighs and trunk, respectively, Paquatic movements. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling the condensation of sulfuric acid and water on the cylinder liner of a large two-stroke marine diesel engine

DEFF Research Database (Denmark)

Cordtz, Rasmus Faurskov; Mayer, Stefan; Eskildsen, Svend S.

2018-01-01

Corrosive wear of cylinder liners in large two-stroke marine diesel engines that burn heavy fuel oil containing sulfur is coupled to the formation of gaseous sulfur trioxide (SO3) and subsequent combined condensation of sulfuric acid (H2SO4) and water (H2O) vapor. The present work seeks to address...... vapor liquid equilibrium. By assuming homogenous cylinder gas mixtures condensation is modeled using a convective heat and mass transfer analogy combined with realistic liner temperature profiles. Condensation of water is significantly altered by the liner temperature and charge air humidity while...... how fuel sulfur content, charge air humidity and liner temperature variations affects the deposition of water and sulfuric acid at low load operation. A phenomenological engine model is applied to simulate the formation of cylinder/bulk gas combustion products and dew points comply with H2O–H2SO4...

Clinical and imaging features associated with intracranial internal carotid artery calcifications in patients with ischemic stroke

Energy Technology Data Exchange (ETDEWEB)

Yilmaz, Arda [Mersin University, Department of Neurology, Faculty of Medicine, Mersin (Turkey); Akpinar, Erhan [Hacettepe University, Department of Radiology, Faculty of Medicine, Ankara (Turkey); Topcuoglu, Mehmet Akif; Arsava, Ethem Murat [Hacettepe University, Department of Neurology, Faculty of Medicine, Ankara (Turkey)

2015-05-01

Intracranial internal carotid artery calcifications (ICAC), a frequent finding on imaging studies, are predictive of future stroke risk in population-based studies. The clinical significance of this observation among ischemic stroke patients is however less clear. In this study, we analyzed ICAC burden in relation to vascular risk factor profile, stroke etiology, and extent of craniocervical vascular calcifications in a consecutive series of ischemic stroke patients. The burden of ICAC was determined both on non-contrast CT and CT-angiography source images by semiquantitative scoring algorithms. The distribution of vascular risk factors, etiologic stroke subtype, and calcification burden in other craniocervical arteries was assessed among patients with no ICAC, mild-moderate ICAC, and severe ICAC. Of 319 patients included into the study, 28 % had no ICAC, 35 % had mild-moderate ICAC, and 37 % had severe ICAC on CT angiography. Independent factors associated with ICAC burden in multivariate analysis included age (p < 0.001), diabetes mellitus (p = 0.006), and coronary artery disease (p < 0.001). Furthermore, a stroke etiology of large artery atherosclerosis or cardioaortic embolism was significantly related to higher ICAC burden (p = 0.006). Patients with severe ICAC were more likely to harbor calcifications in other vascular beds (p < 0.001). All of these findings persisted when analyses were repeated with CT-based ICAC burden assessments. ICAC burden reflects a continuum of atherosclerotic disease involving carotid arteries together with other craniocervical vascular beds. ICAC is significantly associated with stroke of large vessel or cardioembolic origin. This information might help the clinician in prioritizing etiologic work-up in the acute period. (orig.)

Exhaust gas recirculation system for an internal combustion engine

Science.gov (United States)

Wu, Ko-Jen

2013-05-21

An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

The highlighting of an internal combustion engine piston ring radial oscillations

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Djallel ZEBBAR

2016-06-01

Full Text Available This paper deals with the definition of the lube-oil film thickness in the piston ring cylinder liner junction of an internal combustion engine. At first, a mathematical model for the estimation of the film thickness is established. It is used to point out the oscillating motion of the piston ring normal to the cylinder wall. For the first time, has been highlighted and analytically evaluated the oscillating behavior of the piston ring in its housing in the radial direction. Furthermore, it is demonstrated that the radial oscillations frequency is a function of piston ring stiffness, material and geometry.

Assessing the damage importance rank in acoustic diagnostics of technical conditions of the internal combustion engine with multi-valued logical decision trees

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Deptuła Adam

2017-01-01

Full Text Available This paper presents possible applications of acoustic diagnostics in inspecting the technical condition of an internal combustion engine with autoignition on the example of the Fiat drive unit with the common rail system. As a result of measuring the sound pressure level for specific faults and comparing the noise generated by the motor running smoothly, the detailed maps of changes in the acoustic spectrum may be generated. These results may be helpful in future diagnostics of internal combustion engines. In the paper, we present the results from the scientific works in the area of research, design and operation of internal combustion engines, conducted at the Department of Automotive Engineering, in cooperation with the Laboratory of Hydraulic Drives & Vibroacoustics of Machines at the Wroclaw University of Technology. The broader study has so far allowed us to develop an authoritative method of identifying the type of engine damage using gametree structures. The present works assess the possibility of using multi-valued logic trees.

CRITERIA POLLUTANT EMISSIONS FROM INTERNAL COMBUSTION ENGINES IN THE NATURAL GAS INDUSTRY VOLUME 1. TECHNICAL REPORT

Science.gov (United States)

The report summarizes emission factors for criteria pollutants (NOx, CO, CH4, C2H6, THC, NMHC, and NMEHC) from stationary internal combustion engines and gas turbines used in the natural gas industry. The emission factors were calculated from test results from five test campaigns...

MODELING OF ELECTRONIC GASOLINE INJECTION PROCESSES IN TWO STROKE ENGINE

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Hraivoronskyi, Y.

2013-06-01

Full Text Available Basic provision of the processes developed mode, occurring in ignition fuel system with electronically controlled two stroke engine with positive ignition are given. Fuel injection process’ calculation results for the case of placing fuel injector into intake system presented.

Tracer-based laser-induced fluorescence measurement technique for quantitative fuel/air-ratio measurements in a hydrogen internal combustion engine.

Science.gov (United States)

Blotevogel, Thomas; Hartmann, Matthias; Rottengruber, Hermann; Leipertz, Alfred

2008-12-10

A measurement technique for the quantitative investigation of mixture formation processes in hydrogen internal combustion engines (ICEs) has been developed using tracer-based laser-induced fluorescence (TLIF). This technique can be employed to fired and motored engine operation. The quantitative TLIF fuel/air-ratio results have been verified by means of linear Raman scattering measurements. Exemplary results of the simultaneous investigation of mixture formation and combustion obtained at an optical accessible hydrogen ICE are shown.

Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

Science.gov (United States)

Roberts, Jr., Charles E.; Chadwell, Christopher J.

2004-09-21

The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

Meeting stroke survivors' perceived needs: a qualitative study of a community-based exercise and education scheme.

Science.gov (United States)

Reed, Mary; Harrington, Rachel; Duggan, Aine; Wood, Victorine A

2010-01-01

A qualitative study using a phenomenological approach, to explore stroke survivors' needs and their perceptions of whether a community stroke scheme met these needs. Semi-structured in-depth interviews of 12 stroke survivors, purposively selected from participants attending a new community stroke scheme. Interpretative phenomenological analysis of interviews by two researchers independently. Participants attending the community stroke scheme sought to reconstruct their lives in the aftermath of their stroke. To enable this they needed internal resources of confidence and sense of purpose to 'create their social self', and external resources of 'responsive services' and an 'informal support network', to provide direction and encouragement. Participants felt the community stroke scheme met some of these needs through exercise, goal setting and peer group interaction, which included social support and knowledge acquisition. Stroke survivors need a variety of internal and external resources so that they can rebuild their lives positively post stroke. A stroke-specific community scheme, based on exercise, life-centred goal setting, peer support and knowledge acquisition, is an external resource that can help with meeting some of the stroke survivor's needs.

Flex-Fuel Two-Stroke Snowmobile: Development of a Flex-Fuel, Two-Stroke, Direct-Injection Snowmobile for Use in the Clean Snowmobile Challenge and National Parks

Science.gov (United States)

2009-09-01

The University of Idaho's entry into the 2009 SAE Clean Snowmobile Challenge (CSC) was a semi-direct-injection (SDI) two-stroke powered REV-XP snowmobile modified to use flex fuel. The flex fuel engine produces stock engine power on any blend of etha...

Control Scheme Formulation for the Production of Hydrogen on Demand to Feed an Internal Combustion Engine

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Jarniel García Morales

2016-12-01

Full Text Available In this work, a control strategy is presented to produce hydrogen on demand to feed an internal combustion (IC engine. For this purpose, the modeling of the IC engine fueled by gasoline blended with 10 % v/v of anhydrous ethanol (E10 and hydrogen as an additive is developed. It is considered that the hydrogen gas is produced according to the IC engine demand, and that the hydrogen gas is obtained by an alkaline electrolyzer. The gasoline–ethanol blend added into the combustion chamber is determined according to the stoichiometric ratio and the production of hydrogen gas is regulated by a proportional and integral controller (P.I.. The controller reference is varying according to the mass flow air induced into the cylinder, in order to ensure an adequate production of hydrogen gas for any operating condition of the IC engine. The main contribution of this work is the control scheme developed, through simulation, in order to produce hydrogen on demand for any operating point of an internal combustion engine fueled by an E10 blend. The simulation results showed that the use of hydrogen gas as an additive in an E10 blend decreases the E10 fuel consumption 23 % on average, and the thermal efficiency is increased approximately 2.13 % , without brake power loss in the IC engine.

Conversion of a gasoline internal combustion engine to operate on hydrogen fuel

International Nuclear Information System (INIS)

Bates, M.; Dincer, I.

2009-01-01

This study deals with the conversion of a gasoline spark ignition internal combustion engine to operate on hydrogen fuel while producing similar power, economy and reliability as gasoline. The conversion engine will have the fuel system redesigned and ignition and fuel timing changed. Engine construction material is of great importance due to the low ignition energy of hydrogen, making aluminum a desirable material in the intake manifold and combustion chamber. The engine selected to convert is a 3400 SFI dual over head cam General Motors engine. Hydrogen reacts with metals causing hydrogen embrittlement which leads to failure due to cracking. There are standards published by American Society of Mechanical Engineers (ASME) to avoid such a problem. Tuning of the hydrogen engine proved to be challenging due to the basic tuning tools of a gasoline engine such as a wide band oxygen sensor that could not measure the 34:1 fuel air mixture needed for the hydrogen engine. Once the conversion was complete the engine was tested on a chassis dynamometer to compare the hydrogen horsepower and torque produced to that of a gasoline engine. Results showed that the engine is not operating correctly. The engine is not getting the proper amount of fuel needed for complete combustion when operated in a loaded state over 3000 rpm. The problem was found to be the use of the stock injector driver that could not deliver enough power for the proper operation of the larger CM4980 injectors. (author)

Retrospective audit of the acute management of stroke in two district general hospitals in the uk.

Science.gov (United States)

Faluyi, O O; Omodara, J A; Tay, K H; Muhiddin, K

2008-06-01

There is some evidence to suggest that the standard of acute medical care provided to patients with cerebrovascular disease is a major determinant of the eventual outcome. Consequently, the Royal College of Physicians (RCP) of London issues periodic guidelines to assist healthcare providers in the management of patients presenting with stroke. An audit of the acute management of stroke in two hospitals belonging to the same health care trust in the UK. Retrospective review of 98 randomly selected case-notes of patients managed for cerebrovascular disease in two acute hospitals in the UK between April and June 2004. The pertinent guidelines of RCP (London) are highlighted while audit targets were set at 70%. 84% of patients presenting with cerebrovascular disease had a stroke rather than a TIA, anterior circulation strokes were commonest. All patients with stroke were admitted while those with TIAs were discharged on the same day but most patients with TIA were not followed up by Stroke specialists. Most CT-imaging of the head was done after 24 hours delaying the commencement of anti-platelets for patients with ischaemic stroke or neurosurgical referral for haemorrhagic stroke. Furthermore, there was a low rate of referral for carotid ultrasound in patients with anterior circulation strokes. Anti-platelets and statins were commenced for most patients with ischaemic stroke while diabetes was well controlled in most of them. However, ACE-inhibitors and diuretics such as indapamide were under-utilized for secondary prevention in such patients. Warfarin anti-coagulation was underutilized in patients with ischaemic stroke who had underlying chronic atrial fibrillation. While there was significant multi-disciplinary team input, dysphagia and physiotherapy assessments were delayed. Similarly, occupational therapy input and psychological assesment were omitted from the care of most patients. Hospital service provision for the management of cerebrovascular disease needs to

Carburetor for internal combustion engines

Science.gov (United States)

Csonka, John J.; Csonka, Albert B.

1978-01-01

A carburetor for internal combustion engines having a housing including a generally discoidal wall and a hub extending axially from the central portion thereof, an air valve having a relatively flat radially extending surface directed toward and concentric with said discoidal wall and with a central conoidal portion having its apex directed toward the interior of said hub portion. The housing wall and the radially extending surface of the valve define an air passage converging radially inwardly to form an annular valving construction and thence diverge into the interior of said hub. The hub includes an annular fuel passage terminating at its upper end in a circumferential series of micro-passages for directing liquid fuel uniformly distributed into said air passage substantially at said valving constriction at right angles to the direction of air flow. The air valve is adjustable axially toward and away from the discoidal wall of the carburetor housing to regulate the volume of air drawn into the engine with which said carburetor is associated. Fuel is delivered under pressure to the fuel metering valve and from there through said micro-passages and controlled cams simultaneously regulate the axial adjustment of said air valve and the rate of delivery of fuel through said micro-passages according to a predetermined ratio pattern. A third jointly controlled cam simultaneously regulates the ignition timing in accordance with various air and fuel supply settings. The air valve, fuel supply and ignition timing settings are all independent of the existing degree of engine vacuum.

Device for controlling the composition of the mixture burnt in the combustion spaces of an internal combustion engine. Einrichtung zur Regelung der Zusammensetzung des in den Brennraeumen einer Brennkraftmaschine zur Verbrennung kommenden Betriebsgemisches

Energy Technology Data Exchange (ETDEWEB)

Latsch, R; Bianchi, V

1986-07-31

The purpose of the invention is to create a device by which the extent of the reaction to the control of the composition of the mixture burnt in the combustion spaces of an internal combustion engine can be measured in a sensitive, responsive and safe way, where the position of the elements detecting the reaction should have a relatively small effect on the accuracy of the measurement and the extent of measurement. According to the invention, this problem is solved by the use of 2 thermal sensors connected to a control device (photo-electric diode, photo-electric transistor), one of which acts catalytically and causes the parts of the gas mixture there to react. The thermal sensor output signals are periodically integrated via the piston work and are entered in the control device. The measured temperature is a measure of how far the method of operation of the internal combustion engine has approached its limits. (HWJ).

DIAGNOSIS OF FAILURE OF COMBUSTION IN THE COMBUSTION CHAMBER WITH A THERMOVISION EQUIPMENT

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S. V. Vorobiev

2014-01-01

Full Text Available The use of thermovision technology to diagnose failure of the combustion flame test tube of the main combustion chamber gas turbine engine is deal with in the article. Join the thermal radiation of the jet of combustion products and the internal elements was carried out using short-wave thermovision system AGA-782 with spectral spectral filters in several ranges from 3.2 to 5.6 microns. Thermovision is mounted on the axis of the flame tube. The output signal was recorded and processed on a computer in real time, allowing monitor the combustion process and the thermal state of the object during the experiment.

Assessment of test-retest reliability and internal consistency of the Wisconsin Gait Scale in hemiparetic post-stroke patients

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Guzik Agnieszka

2016-09-01

Full Text Available Introduction: A proper assessment of gait pattern is a significant aspect in planning the process of teaching gait in hemiparetic post-stroke patients. The Wisconsin Gait Scale (WGS is an observational tool for assessing post-stroke patients’ gait. The aim of the study was to assess test-retest reliability and internal consistency of the WGS and examine correlations between gait assessment made with the WGS and gait speed, Brunnström scale, Ashworth’s scale and the Barthel Index.

Agreement between routine electronic hospital discharge and Scottish Stroke Care Audit (SSCA) data in identifying stroke in the Scottish population.

Science.gov (United States)

Turner, Melanie; Barber, Mark; Dodds, Hazel; Dennis, Martin; Langhorne, Peter; Macleod, Mary-Joan

2015-12-30

In Scotland all non-obstetric, non-psychiatric acute inpatient and day case stays are recorded by an administrative hospital discharge database, the Scottish Morbidity Record (SMR01). The Scottish Stroke Care Audit (SSCA) collects data from all hospitals managing acute stroke in Scotland to support and improve quality of stroke care. The aim was to assess whether there were discrepancies between these data sources for admissions from 2010 to 2011. Records were matched when admission dates from the two data sources were within two days of each other and if an International Classification of Diseases (ICD) code of I61, I63, I64, or G45 was in the primary or secondary diagnosis field on SMR01. We also carried out a linkage analysis followed by a case-note review within one hospital in Scotland. There were a total of 22 416 entries on SSCA and 22 200 entries on SMR01. The concordance between SSCA and SMR01 was 16 823. SSCA contained 5593 strokes that were not present in SMR01, whereas SMR01 contained 185 strokes that were not present in SSCA. In the case-note review the concordance was 531, with SSCA containing 157 strokes that were not present in SMR01 and SMR01 containing 32 strokes that were not present in SSCA. When identifying strokes, hospital administrative discharge databases should be used with caution. Our results demonstrate that SSCA most accurately represents the number of strokes occurring in Scotland. This resource is useful for determining the provision of adequate patient care, stroke services and resources, and as a tool for research.

Stroke in tuberculous meningitis.

Science.gov (United States)

Misra, Usha Kant; Kalita, Jayantee; Maurya, Pradeep Kumar

2011-04-15

Stroke in tuberculous meningitis (TBM) occurs in 15-57% of patients especially in advance stage and severe illness. The majority of strokes may be asymptomatic because of being in a silent area, deep coma or associated pathology such as spinal arachnoiditis or tuberculoma. Methods of evaluation also influence the frequency of stroke. MRI is more sensitive in detecting acute (DWI) and chronic (T2, FLAIR) stroke. Most of the strokes in TBM are multiple, bilateral and located in the basal ganglia especially the 'tubercular zone' which comprises of the caudate, anterior thalamus, anterior limb and genu of the internal capsule. These are attributed to the involvement of medial striate, thalamotuberal and thalamostriate arteries which are embedded in exudates and likely to be stretched by a coexistent hydrocephalus. Cortical stroke can also occur due to the involvement of proximal portion of the middle, anterior and posterior cerebral arteries as well as the supraclinoid portion of the internal carotid and basilar arteries which are documented in MRI, angiography and autopsy studies. Arteritis is more common than infarction in autopsy study. The role of cytokines especially tumor necrosis factor (TNFα), vascular endothelial growth factor (VEGF) and matrix metaloproteineases (MMPs) in damaging the blood brain barrier, attracting leucocytes and release of vasoactive autocoids have been suggested. The prothrombotic state may also contribute to stroke in TBM. Corticosteroids with antitubercular therapy were thought to reduce mortality and morbidity but their role in reducing strokes has not been proven. Aspirin also reduces mortality and its role in reducing stroke in TBM needs further studies. Copyright © 2010 Elsevier B.V. All rights reserved.

Benchmarking the internal combustion engine and hydrogen

International Nuclear Information System (INIS)

Wallace, J.S.

2006-01-01

The internal combustion engine is a cost-effective and highly reliable energy conversion technology. Exhaust emission regulations introduced in the 1970's triggered extensive research and development that has significantly improved in-use fuel efficiency and dramatically reduced exhaust emissions. The current level of gasoline vehicle engine development is highlighted and representative emissions and efficiency data are presented as benchmarks. The use of hydrogen fueling for IC engines has been investigated over many decades and the benefits and challenges arising are well-known. The current state of hydrogen-fueled engine development will be reviewed and evaluated against gasoline-fueled benchmarks. The prospects for further improvements to hydrogen-fueled IC engines will be examined. While fuel cells are projected to offer greater energy efficiency than IC engines and zero emissions, the availability of fuel cells in quantity at reasonable cost is a barrier to their widespread adaptation for the near future. In their current state of development, hydrogen fueled IC engines are an effective technology to create demand for hydrogen fueling infrastructure until fuel cells become available in commercial quantities. During this transition period, hydrogen fueled IC engines can achieve PZEV/ULSLEV emissions. (author)

Carbon Fiber Reinforced Carbon Composites Rotary Valves for Internal Combustion Engines

Science.gov (United States)

Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

1999-01-01

Carbon fiber reinforced carbon composite rotary, sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or warp-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties, do not present the sealing and lubrication problems that have prevented rotary, sleeve, and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

Exhaust gas turbocharger for internal combustion engines. Abgasturbolader fuer Brennkraftmaschinen

Energy Technology Data Exchange (ETDEWEB)

Behnert, R.; Dommes, W.; Gerwig, W.

1982-01-21

The invention aimes at the heat protection of a turbocharger for internal combustion engines. The turbine is feeded with exhaust gas and drives the shaft of a compressor. For resolving this problem a thermal shield has been installed on the backside of the turbine. The shaft is sealed with an elastic gasket ring. This gasket avoids the deposition of dust and dirt. As a consequence of this constructive measure a growth of tinder and oxides can be avoided as well as the deposition of dirt. A constant reflection factor is ensured. The thermal shield can be manufactured of thin sheet with a nickel surface and can fastened with distance pieces on the backside of the turbine case. Furthermore it is possible to use a ceramic heat shield.

Sensitivity Analysis of Heavy Fuel Oil Spray and Combustion under Low-Speed Marine Engine-Like Conditions

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Lei Zhou

2017-08-01

Full Text Available On account of their high power, thermal efficiency, good reliability, safety, and durability, low-speed two-stroke marine diesel engines are used as the main drive devices for large fuel and cargo ships. Most marine engines use heavy fuel oil (HFO as the primary fuel, however, the physical and chemical characteristics of HFO are not clear because of its complex thermophysical properties. The present study was conducted to investigate the effects of fuel properties on the spray and combustion characteristics under two-stroke marine engine-like conditions via a sensitivity analysis. The sensitivity analysis of fuel properties for non-reacting and reacting simulations are conducted by comparing two fuels having different physical properties, such as fuel density, dynamic viscosity, critical temperature, and surface tension. The performances of the fuels are comprehensively studied under different ambient pressures, ambient temperatures, fuel temperatures, and swirl flow conditions. From the results of non-reacting simulations of HFO and diesel fuel properties in a constant volume combustion chamber, it can be found that the increase of the ambient pressure promotes fuel evaporation, resulting in a reduction in the steady liquid penetration of both diesel and HFO; however, the difference in the vapor penetrations of HFO and diesel reduces. Increasing the swirl flow significantly influences the atomization of both HFO and diesel, especially the liquid distribution of diesel. It is also found that the ambient temperature and fuel temperature have the negative effects on Sauter mean diameter (SMD distribution. For low-speed marine engines, the combustion performance of HFO is not sensitive to activation energy in a certain range of activation energy. At higher engine speed, the difference in the effects of different activation energies on the in-cylinder pressure increases. The swirl flow in the cylinder can significantly promote fuel evaporation and

Update on the third international stroke trial (IST-3 of thrombolysis for acute ischaemic stroke and baseline features of the 3035 patients recruited

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Sandercock Peter

2011-11-01

Full Text Available Abstract Background Intravenous recombinant tissue plasminogen activator (rtPA is approved in Europe for use in patients with acute ischaemic stroke who meet strictly defined criteria. IST-3 sought to improve the external validity and precision of the estimates of the overall treatment effects (efficacy and safety of rtPA in acute ischaemic stroke, and to determine whether a wider range of patients might benefit. Design International, multi-centre, prospective, randomized, open, blinded endpoint (PROBE trial of intravenous rtPA in acute ischaemic stroke. Suitable patients had to be assessed and able to start treatment within 6 hours of developing symptoms, and brain imaging must have excluded intracranial haemorrhage and stroke mimics. Results The initial pilot phase was double blind and then, on 01/08/2003, changed to an open design. Recruitment began on 05/05/2000 and closed on 31/07/2011, by which time 3035 patients had been included, only 61 (2% of whom met the criteria for the 2003 European approval for thrombolysis. 1617 patients were aged over 80 years at trial entry. The analysis plan will be finalised, without reference to the unblinded data, and published before the trial data are unblinded in early 2012. The main trial results will be presented at the European Stroke Conference in Lisbon in May 2012 with the aim to publish simultaneously in a peer-reviewed journal. The trial result will be presented in the context of an updated Cochrane systematic review. We also intend to include the trial data in an individual patient data meta-analysis of all the relevant randomised trials. Conclusion The data from the trial will: improve the external validity and precision of the estimates of the overall treatment effects (efficacy and safety of iv rtPA in acute ischaemic stroke; provide: new evidence on the balance of risk and benefit of intravenous rtPA among types of patients who do not clearly meet the terms of the current EU approval; and

TOPSIS Multi-Criteria Decision Modeling Approach for Biolubricant Selection for Two-Stroke Petrol Engines

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Masoud Dehghani Soufi

2015-12-01

Full Text Available Exhaust pollutants from two-stroke petrol engines are a problem for the environment. Biolubricants are a new generation of renewable and eco-friendly vegetable-based lubricants, which have attracted a lot of attention in recent years. In this paper, the applicability of the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS method to support the process of building the scoring system for selecting an appropriate two-stroke lubricant has been analyzed. For this purpose, biolubricants (TMP-triesters based on castor oil, palm oil, and waste cooking oil were produced and then utilized in a 200 cc two-stroke gasoline engine to investigate their effects on its performance and exhaust emissions. The results obtained from the use of the entropy technique in the TOPSIS algorithm showed that palm oil-based lubricant took up the greatest distance from the Negative Ideal Solution (NIS and was selected as the most optimal lubricant for these types of engines.

Design and Implementation of the Control System of an Internal Combustion Engine Test Unit

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Tufan Koç

2014-02-01

Full Text Available Accurate tests and performance analysis of engines are required to minimize measurement errors and so the use of the advanced test equipment is imperative. In other words, the reliable test results depend on the measurement of many parameters and recording the experimental data accurately which is depended on engine test unit. This study aims to design the control system of an internal combustion engine test unit. In the study, the performance parameters of an available internal combustion engine have been transferred to computer in real time. A data acquisition (DAQ card has been used to transfer the experimental data to the computer. Also, a user interface has been developed for performing the necessary procedures by using LabVIEW. The dynamometer load, the fuel consumption, and the desired speed can easily be adjusted precisely by using DAQ card and the user interface during the engine test. Load, fuel consumption, and temperature values (the engine inlet-outlet, exhaust inlet-outlet, oil, and environment can be seen on the interface and also these values can be recorded to the computer. It is expected that developed system will contribute both to the education of students and to the researchers’ studies and so it will eliminate a major lack.

Hydrogen-oxygen powered internal combustion engine

Science.gov (United States)

Cameron, H.; Morgan, N.

1970-01-01

Hydrogen at 300 psi and oxygen at 800 psi are injected sequentially into the combustion chamber to form hydrogen-rich mixture. This mode of injection eliminates difficulties of preignition, detonation, etc., encountered with carburated, spark-ignited, hydrogen-air mixtures. Ignition at startup is by means of a palladium catalyst.

Carbonaceous species emitted from handheld two-stroke engines

Science.gov (United States)

Volckens, John; Olson, David A.; Hays, Michael D.

Small, handheld two-stroke engines used for lawn and garden work (e.g., string trimmers, leaf blowers, etc.) can emit a variety of potentially toxic carbonaceous air pollutants. Yet, the emissions effluents from these machines go largely uncharacterized, constraining the proper development of human exposure estimates, emissions inventories, and climate and air quality models. This study samples and evaluates chemical pollutant emissions from the dynamometer testing of six small, handheld spark-ignition engines—model years 1998-2002. Four oil-gas blends were tested in each engine in duplicate. Emissions of carbon dioxide, carbon monoxide, and gas-phase hydrocarbons were predominant, and the PM emitted was organic matter primarily. An ANOVA model determined that engine type and control tier contributed significantly to emissions variations across all identified compound classes; whereas fuel blend was an insignificant variable accounting for engines were generally intermediate in magnitude compared with other gasoline-powered engines, numerous compounds traditionally viewed as motor vehicle markers are also present in small engine emissions in similar relative proportions. Given that small, handheld two-stroke engines used for lawn and garden work account for 5-10% of total US emissions of CO, CO 2, NO x, HC, and PM 2.5, source apportionment models and human exposure studies need to consider the effect of these small engines on ambient concentrations in air polluted environments.

Late night activity regarding stroke codes: LuNAR strokes.

Science.gov (United States)

Tafreshi, Gilda; Raman, Rema; Ernstrom, Karin; Rapp, Karen; Meyer, Brett C

2012-08-01

similarity was further supported in similar rates of tissue plasminogen activator administration. Late night strokes may warrant a more rapid stroke specialist evaluation due to the longer time elapsed from symptom onset and the longer time to computed tomography scan. © 2011 The Authors. International Journal of Stroke © 2011 World Stroke Organization.

CRITERIA POLLUTANT EMISSIONS FROM INTERNAL COMBUSTION ENGINES IN THE NATURAL GAS INDUSTRY VOLUME II. APPENDICES A-I

Science.gov (United States)

The report summarizes emission factors for criteria pollutants (NOx, CO, CH4, C2H6, THC, NMHC, and NMEHC) from stationary internal combustion engines and gas turbines used in the natural gas industry. The emission factors were calculated from test results from five test campaigns...

Knowledge of Stroke Risk Factors among Stroke Survivors in Nigeria

OpenAIRE

Grace Vincent-Onabajo; Taritei Moses

2016-01-01

Background. Knowledge of stroke risk factors is expected to reduce the incidence of stroke?whether first-ever or recurrent. This study examined knowledge of stroke risk factors and its determinants among stroke survivors. Methods. A cross-sectional survey of consenting stroke survivors at two physiotherapy facilities in Nigeria was carried out. Sociodemographic and clinical data were obtained and knowledge of stroke risk factors (defined as the ability to mention at least one correct risk fac...

Ipsilateral hemiparesis in ischemic stroke patients.

Science.gov (United States)

Inatomi, Y; Nakajima, M; Yonehara, T; Ando, Y

2017-07-01

To investigate clinical characteristics of ipsilateral hemiparesis in ischemic stroke patients. Patients with acute ischemic stroke were prospectively examined. Ipsilateral hemiparesis was defined as hemiparesis ipsilateral to recent stroke lesions. Patients with ipsilateral hemiparesis were examined with functional neuroimaging studies including transcranial magnetic stimulation (TMS) and functional MRI. Of 8360 patients, ipsilateral hemiparesis was detected in 14 patients (0.17%, mean age 71±6 years, eight men). Lesions responsible for the recent strokes were located in the frontal cortex in three patients, corona radiata in seven, internal capsule in one, and pons in three. These lesions were located along the typical route of the corticospinal tract in all but one patient. Thirteen patients also had a past history of stroke contralateral to the recent lesions; 12 of these had motor deficits contralateral to past stroke lesions. During TMS, ipsilateral magnetic evoked potentials were evoked in two of seven patients and contralateral potentials were evoked in all seven. Functional MRI activated cerebral hemispheres ipsilaterally in eight of nine patients and contralaterally in all nine. Most patients with ipsilateral hemiparesis had a past history of stroke contralateral to the recent one, resulting in motor deficits contralateral to the earlier lesions. Moreover, functional neuroimaging findings indicated an active crossed corticospinal tract in all of the examined patients. Both findings suggest the contribution of the uncrossed corticospinal tract contralateral to stroke lesions as a post-stroke compensatory motor system. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Proceedings of the 12. meeting of the International Post-Combustion CO{sub 2} Capture Network

Energy Technology Data Exchange (ETDEWEB)

Topper, J. [IEA Greenhouse Gas R and D Programme, Cheltenham, Gloucestershire (United Kingdom)] (comp.)

2009-07-01

This conference provided a forum to discuss new developments in post combustion capture of carbon dioxide (CO{sub 2}) emissions from fossil-fueled power plants. Since the creation of the Post-Combustion Capture Network in 2000, these conferences have provided exposure to latest research findings, acted as a conduit for trial of latest ideas and served as a means of encouraging trans-national co-operation. As host of the conference, the University of Regina is among the leading institutions in the world with expertise in working on solvent based capture and promoting international activity through the International Test Centre. The topics of discussion ranged from amine based solvent investigations; ammonia as an alternative means of capture; pilot plant progress reports; simulation and modelling studies; latest developments by technology providers; national programs with a special interest in demonstration plant proposals; and more novel techniques such as membranes. The sessions of the conference were entitled: fundamental studies; pilot plant work and scale-up; modelling and plant studies; and commercial and other aspects. This meeting featured 49 presentations, of which 46 have been catalogued separately for inclusion in this database. refs., figs.

Experimental validation for combustion analysis of GOTHIC code in 2-dimensional combustion chamber

International Nuclear Information System (INIS)

Lee, J. W.; Yang, S. Y.; Park, K. C.; Jung, S. H.

2002-01-01

In this study, the prediction capability of GOTHIC code for hydrogen combustion phenomena was validated with the results of two-dimensional premixed hydrogen combustion experiment executed by Seoul National University. The experimental chamber has about 24 liter free volume (1x0.024x1 m 3 ) and 2-dimensional rectangular shape. The test were preformed with 10% hydrogen/air gas mixture and conducted with combination of two igniter positions (top center, top corner) and two boundary conditions (bottom full open, bottom right half open). Using the lumped parameter and mechanistic combustion model in GOTHIC code, the SNU experiments were simulated under the same conditions. The GOTHIC code prediction of the hydrogen combustion phenomena did not compare well with the experimental results. In case of lumped parameter simulation, the combustion time was predicted appropriately. But any other local information related combustion phenomena could not be obtained. In case of mechanistic combustion analysis, the physical combustion phenomena of gas mixture were not matched experimental ones. In boundary open cases, the GOTHIC predicted very long combustion time and the flame front propagation could not simulate appropriately. Though GOTHIC showed flame propagation phenomenon in adiabatic calculation, the induction time of combustion was still very long compare with experimental results. Also, it was found that the combustion model of GOTHIC code had some weak points in low concentration of hydrogen combustion simulation

Proceedings of the Sixth International Conference on Fluidized Bed Combustion. Volume 1. Plenary sessions

Energy Technology Data Exchange (ETDEWEB)

None

1980-08-01

The Sixth International Conference on Fluidized Bed Combustion was held at the Atlanta Hilton, Atlanta, Georgia, April 9-11, 1980. The papers in this volume involved presentation of the research and development programs of the US (US DOE, TVA, EPRI and US EPA), United Kingdom, Federal Republic of Germany and the People's Republic of China. Eight papers from Vol. 1 (Plenary Sessions) of the proceedings have been entered individually into EDB and ERA. (LTN)

Conflict between internal combustion engine and thermoelectric generator during waste heat recovery in cars

Science.gov (United States)

Korzhuev, M. A.

2011-02-01

It is shown that an internal combustion engine and a thermoelectric generator (TEG) arranged on the exhaust pipe of this engine come into the conflict of thermal machines that is related to using the same energy resource. The conflict grows with increasing useful electric power W e of the TEG, which leads to the limitation of both the maximum TEG output power ( W {e/max}) and the possibility of waste heat recovery in cars.

Some comments on combusting flows and instrumentation for two-phase flows

International Nuclear Information System (INIS)

Whitelaw, J.H.

1985-01-01

Measurements of the velocity characteristics of combusting flows have been reported over the past 15 years and have Encompassed an extensive range of flows configurations. Difficulties in applying instrumentation and interpreting results are, however, still experienced and this presentation describes two experiments which are useful examples of successful applications. The first is concerned with a gas-turbine combustion chamber which involves limited optical access with high heat release but does not require measurement accuracy such as that of, for example, external aerodynamic flows. The second combines laser velocimetry with digitally compensated thermocouples to provide detailed information of a premixed, bluff-body stabilized flame and involves conditionally sampled results so as to determine the separate flow characteristics of products and reactants

Numerical study of heat transfer and combustion in IC engine with a porous media piston region

International Nuclear Information System (INIS)

Zhou, Lei; Xie, Mao-Zhao; Luo, Kai Hong

2014-01-01

Based on superadiabatic combustion in porous medium (PM), the porous medium engine as a new combustion concept is proposed to achieve high combustion efficiency and low emissions. In this paper, an axisymmetric model with detailed chemistry and two-temperature treatment is implemented into a variant of the KIVA-3V code to simulate the working process of the PM engine. Comparisons with the same engine but without PM are conducted. Temperature evolution of the PM and its effects are discussed in detail. Key factors affecting heat transfer, combustion and emissions of the PM engine, such as porosity, the initial PM temperature and equivalence ratio, are analyzed. The results show that the characteristics of heat transfer, emissions and combustion of the PM engine are superior to the engine without PM, providing valuable support for the PM engine concept. In particular, the PM engine is shown to sustain ultra lean combustion. - Graphical abstract: In the PM engine, a PM reactor is mounted on the piston head as shown in Fig. 1 which shows the schematic diagram of the computational domain. The heat exchange process between PM material and compressed air increases with upward motion of piston at compression stroke. At the TDC, almost all the air is compressed and closed to PM volume, meanwhile, the fuel is injected into PM chamber to achieve homogenization combustion. - Highlights: •Two-temperature treatment studies the working process of the PM engine. •Self-balancing temperature of the PM determines the continued and stable work. •Stronger heat exchange occurs between gas and PM with smaller porosity. •The PM engine can have lower levels of NO x , unburnt HC and CO emissions

Possibility of reducing CO2 emissions from internal combustion engines

Science.gov (United States)

Drabik, Dawid; Mamala, Jarosław; Śmieja, Michał; Prażnowski, Krzysztof

2017-10-01

Article defines on the possibility of reduction CO2 of the internal combustion engine and presents the analysis based on originally conducted studies. The increase in overall engine efficiency is sought after by all engineers dealing with engine construction, one of the major ways to reduce CO2 emissions is to increase the compression ratio. The application of the compression ratio that has been increased constructional in the engine will, on one hand, bring about the increase in the theoretical efficiency, but, on the other hand, require a system for pressure control at a higher engine load in order to prevent engine knocking. For the purposes of the article there was carried out a number of studies and compiled results, and on their basis determined what have a major impact on the reducing CO2.

Predictive piston motion control in a free-piston internal combustion engine

Energy Technology Data Exchange (ETDEWEB)

Mikalsen, R.; Jones, E.; Roskilly, A.P. [Sir Joseph Swan Institute for Energy Research, Newcastle University, Newcastle upon Tyne, NE1 7RU England (United Kingdom)

2010-05-15

A piston motion controller for a free-piston internal combustion engine is presented. To improve dynamic performance in the control of the piston motion and engine compression ratio, the controller response is determined from a prediction of engine top dead centre error rather than the measured value from the previous cycle. The proposed control approach showed superior performance compared with that of standard PI feedback control known from the literature due to a reduced control action time delay. The manipulation of fuel injection timing to reduce in-cylinder pressure peaks and cycle-to-cycle variations was also studied, indicating that with the piston motion estimation, the injection timing is a powerful control variable for this purpose. (author)

Motor vehicles and internal combustion engines; Kraftfahrwesen und Verbrennungsmotoren

Energy Technology Data Exchange (ETDEWEB)

Bargende, M.; Wiedemann, J. [eds.

1999-07-01

The book comprises the papers presented at the 3rd Stuttgart symposium. It reviews the state of the art in science and engineering and outlines future perspectives in the fields of motor vehicles and internal combustion engines. As the conference, the book comprises three sections: 'Engines' on DI spark ignition engines and diesel engines, mixing, combustion and exhaust purification. 'Motor cars' discusses acoustics and aeroacoustics, aerodynamics and wind tunnel technology, comfort, driving gear and stability control. 'Motor vehicle systems' contains papers on thermomanagement, control and automation, real-time applications in motor car simulation, software tools in the control systems development process, and simulation in motor vehicle systems development. Finally, the plenary paper 'Fuel cells, a solution for non-polluting motor car drives' by Dr.-Ing. F. Panik is also contained in the book. [German] Das vorliegende Buch enthaelt die Vortraege des 3. Stuttgarter Symposiums. Es gibt einen Ueberblick ueber den aktuellen Stand von Wissenschaft und Technik und zeigt zukuenftige Perspektiven im Bereich Kraftfahrwesen und Verbrennungsmotoren. Entsprechend der Tagung gliedert sich das Buch in drei Teile. Teil 1 'Motoren' besteht aus Vortraegen ueber Ottomotoren mit Direkteinspritzung und Dieselmotoren, Gemischbildung, Verbrennung und Abgasnachbehandlung, Analyse, Simulation und Motorkomponenten. Teil 2 'Kraftfahrzeuge' enthaelt Arbeiten ueber Fahrzeugakustik und Aeroakustik, Fahrzeug-Aerodynamik und Windkanaltechnik, Fahrzeugkomfort, Fahrwerk und Fahrdynamik. Teil 3 'Kraftfahrzeugsystemtechnik' enthaelt Beitraege ueber Thermomanagement, Regelungs- und Automatisierungstechnik, Echtzeitanwendungen in der Kfz-Simulationstechnik, Softwaretools im Steuergeraete-Entwicklungsprozess und Simulation in der Kraftfahrzeug-Systementwicklung. Der abschliessende Plenarvortrag des Symposiums &apos

Scavenging processes in high speed two-stroke engines studied with laser diagnostics

Energy Technology Data Exchange (ETDEWEB)

Ekenberg, M.

1998-12-31

The major problem with the carburetted two-stroke engine is the short-circuiting of fuel that occurs during the scavenging phase. This leads to large emissions of unburned hydrocarbons. The object of this thesis has been to map the flow behaviour in the cylinder during the scavenging phase, and to detect differences between different cylinder designs. The measurement techniques used has been Laser Doppler Velocimetry (LDV), Laser Induced Fluorescence (LIF) and Laser Sheet Droplet Illumination (LSDI). Of these measurement methods, LDV and LSDI has been used inside the cylinder. LIF was used outside the exhaust port. All measurements were performed in engines running at their rated speeds, 9000 rpm for three of the designs and 5800 rpm for one design. All engines were run at full load with combustion. The LDV measurements inside the cylinder show that cylinders with cup handle transfer channels have a flow pattern inside the cylinder that gives less short-circuiting, and hence less emissions of hydrocarbons, than the cylinder with open transfer channels has. The LIF measurements outside the exhaust port show that the HC emissions that are caused by short-circuiting comes earlier in the scavenging phase for the cylinder with open transfer channels than is the case for the cylinders with cup handle transfer channels. The LSDI measurements in the cylinder give the transfer channel flow angle, for the cylinders with cup handle transfer channels. For the cylinder with open transfer channels, the results are not as useful; fuel droplet vaporization close to the exhaust port ruins the results 35 refs, 43 figs

Numerical Study on the Performance Characteristics of Hydrogen Fueled Port Injection Internal Combustion Engine

OpenAIRE

Rosli A. Bakar; Mohammed K. Mohammed; M. M. Rahman

2009-01-01

This study was focused on the engine performance of single cylinder hydrogen fueled port injection internal combustion engine. GT-Power was utilized to develop the model for port injection engine. One dimensional gas dynamics was represented the flow and heat transfer in the components of the engine model. The governing equations were introduced first, followed by the performance parameters and model description. Air-fuel ratio was varied from stoichiometric limit to a lean limit and the rota...

Equipment for heating the exhaust gases of internal combustion engines in order to improve afterburning

Energy Technology Data Exchange (ETDEWEB)

Masaki,

1976-04-15

The device described here serves to heat exhaust gases of internal combustion engines by heat exchange with hot gases and also, in cold engines, to raise the temperature of the fuel-air mixture drawn in by the engine. The device is installed next to the outlet opening of the engine. It consists of a burner to generate the hot gas, as well as a heat exchanger permitting heat supply to the exhaust gases and a hot-gas line leading to the intake line. Heating of the air is taken in leads to a better atomization of the mixture and thus to improved combustion. Heating of the exhaust gases improves afterburning. The burner generating the hot gas is shut off when the normal operational temperature of the engine is reached. The temperature is controlled by means of a temperature sensor installed in the device.

Stroke Prevention Trials in Sickle Cell Anemia

Directory of Open Access Journals (Sweden)

J Gordon Millichap

2006-06-01

Full Text Available As part of an International Pediatric Stroke Study launched in 2002, the Stroke Prevention Trial in Sickle Cell Anemia (STOP reports a reduction in the number of overt clinical strokes in children with critically high transcranial Doppler velocities (>200 cm/sec who were regularly transfused.

Numerical investigation of CAI Combustion in the Opposed- Piston Engine with Direct and Indirect Water Injection

Science.gov (United States)

Pyszczek, R.; Mazuro, P.; Teodorczyk, A.

2016-09-01

This paper is focused on the CAI combustion control in a turbocharged 2-stroke Opposed-Piston (OP) engine. The barrel type OP engine arrangement is of particular interest for the authors because of its robust design, high mechanical efficiency and relatively easy incorporation of a Variable Compression Ratio (VCR). The other advantage of such design is that combustion chamber is formed between two moving pistons - there is no additional cylinder head to be cooled which directly results in an increased thermal efficiency. Furthermore, engine operation in a Controlled Auto-Ignition (CAI) mode at high compression ratios (CR) raises a possibility of reaching even higher efficiencies and very low emissions. In order to control CAI combustion such measures as VCR and water injection were considered for indirect ignition timing control. Numerical simulations of the scavenging and combustion processes were performed with the 3D CFD multipurpose AVL Fire solver. Numerous cases were calculated with different engine compression ratios and different amounts of directly and indirectly injected water. The influence of the VCR and water injection on the ignition timing and engine performance was determined and their application in the real engine was discussed.

Relationship between functional disability and costs one and two years post stroke

Science.gov (United States)

Lekander, Ingrid; Willers, Carl; von Euler, Mia; Lilja, Mikael; Sunnerhagen, Katharina S.; Pessah-Rasmussen, Hélène; Borgström, Fredrik

2017-01-01

Background and purpose Stroke affects mortality, functional ability, quality of life and incurs costs. The primary objective of this study was to estimate the costs of stroke care in Sweden by level of disability and stroke type (ischemic (IS) or hemorrhagic stroke (ICH)). Method Resource use during first and second year following a stroke was estimated based on a research database containing linked data from several registries. Costs were estimated for the acute and post-acute management of stroke, including direct (health care consumption and municipal services) and indirect (productivity losses) costs. Resources and costs were estimated per stroke type and functional disability categorised by Modified Rankin Scale (mRS). Results The results indicated that the average costs per patient following a stroke were 350,000SEK/€37,000–480,000SEK/€50,000, dependent on stroke type and whether it was the first or second year post stroke. Large variations were identified between different subgroups of functional disability and stroke type, ranging from annual costs of 100,000SEK/€10,000–1,100,000SEK/€120,000 per patient, with higher costs for patients with ICH compared to IS and increasing costs with more severe functional disability. Conclusion Functional outcome is a major determinant on costs of stroke care. The stroke type associated with worse outcome (ICH) was also consistently associated to higher costs. Measures to improve function are not only important to individual patients and their family but may also decrease the societal burden of stroke. PMID:28384164

Relationship between functional disability and costs one and two years post stroke.

Directory of Open Access Journals (Sweden)

Ingrid Lekander

Full Text Available Stroke affects mortality, functional ability, quality of life and incurs costs. The primary objective of this study was to estimate the costs of stroke care in Sweden by level of disability and stroke type (ischemic (IS or hemorrhagic stroke (ICH.Resource use during first and second year following a stroke was estimated based on a research database containing linked data from several registries. Costs were estimated for the acute and post-acute management of stroke, including direct (health care consumption and municipal services and indirect (productivity losses costs. Resources and costs were estimated per stroke type and functional disability categorised by Modified Rankin Scale (mRS.The results indicated that the average costs per patient following a stroke were 350,000SEK/€37,000-480,000SEK/€50,000, dependent on stroke type and whether it was the first or second year post stroke. Large variations were identified between different subgroups of functional disability and stroke type, ranging from annual costs of 100,000SEK/€10,000-1,100,000SEK/€120,000 per patient, with higher costs for patients with ICH compared to IS and increasing costs with more severe functional disability.Functional outcome is a major determinant on costs of stroke care. The stroke type associated with worse outcome (ICH was also consistently associated to higher costs. Measures to improve function are not only important to individual patients and their family but may also decrease the societal burden of stroke.

Public perception related to a hydrogen hybrid internal combustion engine transit bus demonstration and hydrogen fuel

International Nuclear Information System (INIS)

Hickson, Allister; Phillips, Al; Morales, Gene

2007-01-01

Hydrogen has been widely considered as a potentially viable alternative to fossil fuels for use in transportation. In addition to price competitiveness with fossil fuels, a key to its adoption will be public perceptions of hydrogen technologies and hydrogen fuel. This paper examines public perceptions of riders of a hydrogen hybrid internal combustion engine bus and hydrogen as a fuel source

Novel Tribotester for Cylinder Liner/Piston Ring Contacts of Two Stroke Marine Diesel Engines

DEFF Research Database (Denmark)

Pedersen, Michael Torben; Imran, Tajammal; Klit, Peder

2009-01-01

A good tribological description for the cylinder liner and piston ring materials is always desired in order to achieve an improved combination of the materials. The piston ring package in a two-stroke-diesel engine operates in three lubrication regimes and the materials must be characterized...... in relation to this before a final selection is made. A tribo-test-apparatus is developed to study the tribological performance and to rank the different combinations of cylinder liner and piston ring materials of two stroke marine diesel engines. The test apparatus is based on the block-on-ring principle...

六ストロークディーゼル機関の性能

OpenAIRE

岡本, 雄一郎; 荻原, 五郎; 天谷, 賢児; 新井, 雅隆

1998-01-01

A Six-stroke diesel engine was developed and its performance was evaluated. This engine had second compression and second combustion strokes which were added on the four stroke diesel engine. To control the fuel injection ratio and injection timings for first and second combustion strokes independently, two fuel pumps were attached to the engine. Effect of the fuel allocation ratio between first and second combustion strokes on the engine performance was investigated. Engine performance of th...

Effectiveness of two rehabilitation strategies provided by nurses for stroke patients in Mexico.

Science.gov (United States)

Torres-Arreola, Laura del Pilar; Doubova Dubova, Svetlana Vladislavovna; Hernandez, Sergio F; Torres-Valdez, Laura E; Constantino-Casas, Norma P; Garcia-Contreras, Fernando; Torres-Castro, Sara

2009-11-01

Rehabilitation strategies have been developed to improve functional state in stroke patients. The main objective of this study was to evaluate the effectiveness of the early rehabilitation at hospital and its continuity at home provided by nurses, on the functional recovery of basic and social activities in stroke patients compared with conventional care. A randomised clinical trial was carried out in three general hospitals of the Mexican Institute of Social Security (IMSS) in Mexico City between April 2003-May 2004. Stroke patients. Two rehabilitation strategies provided by nurses for stroke patients were compared: physiotherapy plus caregiver education in rehabilitation (strategy 1, S1) vs. education alone (strategy 2, S2). The main outcome variables were the basic (Barthel index) and social (Frenchay activities index) activities of daily living, of each patient. Age, sex, morbidity, stroke symptoms, complications, neurological damage (Canadian Scale), cognitive state (mini-mental state examination questionnaire) and duration of hospitalisation were defined as the control variables. Patients were evaluated at baseline and months one, three and six thereafter. One hundred and ten patients with ischaemic stroke were enrolled and randomised; 59 were assigned to S1 and 51 to S2. Comparison of the outcome variables showed that patients improved significantly over time, but no differences were observed between groups. We observed no significant difference in strategy performance with regard to the basic and instrumental activities of daily living. Participants who received physiotherapy with additional caregiver education benefit no more than those whose caregivers received education alone. Those countries that do not have integral rehabilitation programmes for stroke patients should understand their importance and budget resources for them. Meanwhile, both caregiver education and nurses trained in specific care and physiotherapy are alternatives that benefit these

Effects of Centralizing Acute Stroke Services on Stroke Care Provision in Two Large Metropolitan Areas in England

Science.gov (United States)

Morris, Stephen; Hoffman, Alex; Hunter, Rachael M.; Boaden, Ruth; McKevitt, Christopher; Perry, Catherine; Pursani, Nanik; Rudd, Anthony G.; Turner, Simon J.; Tyrrell, Pippa J.; Wolfe, Charles D.A.; Fulop, Naomi J.

2015-01-01

Background and Purpose— In 2010, Greater Manchester and London centralized acute stroke care into hyperacute units (Greater Manchester=3, London=8), with additional units providing ongoing specialist stroke care nearer patients’ homes. Greater Manchester patients presenting within 4 hours of symptom onset were eligible for hyperacute unit admission; all London patients were eligible. Research indicates that postcentralization, only London’s stroke mortality fell significantly more than elsewhere in England. This article attempts to explain this difference by analyzing how centralization affects provision of evidence-based clinical interventions. Methods— Controlled before and after analysis was conducted, using national audit data covering Greater Manchester, London, and a noncentralized urban comparator (38 623 adult stroke patients, April 2008 to December 2012). Likelihood of receiving all interventions measured reliably in pre- and postcentralization audits (brain scan; stroke unit admission; receiving antiplatelet; physiotherapist, nutrition, and swallow assessments) was calculated, adjusting for age, sex, stroke-type, consciousness, and whether stroke occurred in-hospital. Results— Postcentralization, likelihood of receiving interventions increased in all areas. London patients were overall significantly more likely to receive interventions, for example, brain scan within 3 hours: Greater Manchester=65.2% (95% confidence interval=64.3–66.2); London=72.1% (71.4–72.8); comparator=55.5% (54.8–56.3). Hyperacute units were significantly more likely to provide interventions, but fewer Greater Manchester patients were admitted to these (Greater Manchester=39%; London=93%). Differences resulted from contrasting hyperacute unit referral criteria and how reliably they were followed. Conclusions— Centralized systems admitting all stroke patients to hyperacute units, as in London, are significantly more likely to provide evidence-based clinical

Carbon Fiber Reinforced Carbon Composite Rotary Valve for an Internal Combustion Engine

Science.gov (United States)

Northam, G.Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

2000-01-01

Carbon fiber reinforced carbon composite rotary sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or wrap-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties do not present the sealing and lubrication problems that have prevented rotary sleeve and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

Vibration survey of internal combustion engines for use on unmanned air vehicles

International Nuclear Information System (INIS)

Duanis, B.

1998-01-01

This paper describes the method, the procedure and data results of engine vibration test which is carried out on engines for use on unmanned air vehicles. The paper focuses on the testing of rotating propulsion systems powered by an internal combustion engine which is composed of main rotating components such as the alternator, gearbox, propeller , dampers and couplings. Three measurement methods for measuring torsional and lateral vibrations are presented: a. Gear tooth pulse signal. b. Shaft Strain Gage. c. Laser Displacement Sensors The paper also presents data from tests which were performed using each method and discusses the applications, the advantages and disadvantages of each method

Suboptimal lipid management before and after ischaemic stroke and TIA-the North Dublin Population Stroke Study.

Science.gov (United States)

Ní Chróinín, Danielle; Ní Chróinín, Chantelle; Akijian, Layan; Callaly, Elizabeth L; Hannon, Niamh; Kelly, Lisa; Marnane, Michael; Merwick, Áine; Sheehan, Órla; Horgan, Gillian; Duggan, Joseph; Kyne, Lorraine; Dolan, Eamon; Murphy, Seán; Williams, David; Kelly, Peter J

2018-01-24

Few population-based studies have assessed lipid adherence to international guidelines for primary and secondary prevention in stroke/transient ischaemic attack (TIA) patients. This study aims to evaluate adherence to lipid-lowering therapy (LLT) guidelines amongst patients with ischaemic stroke/TIA. Using hot and cold pursuit methods from multiple hospital/community sources, all stroke and TIA cases in North Dublin City were prospectively ascertained over a 1-year period. Adherence to National Cholesterol Education Programme (NCEP) III guidelines, before and after index ischaemic stroke/TIA, was assessed. Amongst 616 patients (428 ischaemic stroke, 188 TIA), total cholesterol was measured following the qualifying event in 76.5% (471/616) and low-density lipoprotein (LDL) in 60.1% (370/616). At initial stroke/TIA presentation, 54.1% (200/370) met NCEP III LDL goals. Compliance was associated with prior stroke (odds ratio [OR] 2.19, p = 0.02), diabetes (OR 1.91, p = 0.04), hypertension (OR 1.57, p = 0.03), atrial fibrillation (OR 1.78, p = 0.01), pre-event LLT (OR 2.85, p TIA onset, 32.7% (195/596) was on LLT. Nonetheless, LDL exceeded individual NCEP goal in 29.2% (56/192); 21.6% (53/245) warranting LLT was not on treatment prior to stroke/TIA onset. After index stroke/TIA, 75.9% (422/556) was on LLT; 15.3% (30/196) meeting NCEP III criteria was not prescribed a statin as recommended. By 2 years, actuarial survival was 72.8% and 11.9% (59/497) experienced stroke recurrence. No association was observed between initial post-event target adherence and 2-year outcomes. In this population-based study, LLT recommended by international guidelines was under-used, before and after index stroke/TIA. Strategies to improve adherence are needed.

Self adaptive internal combustion engine control for hydrogen mixtures using piezoelectric transducers for dynamic cylinder pressure monitoring

Energy Technology Data Exchange (ETDEWEB)

Courteau, R.; Bose, T.K. [Quebec Univ., Trois-Rivieres, PQ (Canada). Institut de recherche sur l' hydrogene

2004-07-01

Hydrogen internal combustion engine research at the Hydrogen Research Institute includes the following infrastructure: a 20 square metre test cell, an engine preparation room, a 150 hp dynamometer, exhaust gas analysers and a hydrogen supply. The goal of the research is to develop internal combustion engine technologies that can use hydrogen as a fuel without knocking, backfires, excessive engine wear, and with low emissions. As well as hydrogen, fuels such as biogas are also investigated. Technologies under investigation include adaptive control algorithms, as well as advanced sensors and actuators. The latter include piezolelectrics, optical fibres, nitrogen oxide detectors, and chemical composition detectors. Developments include microprocessor-controlled injection and ignition control systems for both single cylinder and multicylinder engines. Research on the influence of fuel composition on best ignition timing is presented. There is also dynamic cylinder pressure monitoring to prevent knocking make engine state assessments and perform engine calibration. Piezoelectric cylinder pressure sensors are employed, either integrated with the spark plugs, or stand-alone, inserted through separate holes through the cylinder head. tabs, figs.

Application of a high-repetition-rate laser diagnostic system for single-cycle-resolved imaging in internal combustion engines.

Science.gov (United States)

Hult, Johan; Richter, Mattias; Nygren, Jenny; Aldén, Marcus; Hultqvist, Anders; Christensen, Magnus; Johansson, Bengt

2002-08-20

High-repetition-rate laser-induced fluorescence measurements of fuel and OH concentrations in internal combustion engines are demonstrated. Series of as many as eight fluorescence images, with a temporal resolution ranging from 10 micros to 1 ms, are acquired within one engine cycle. A multiple-laser system in combination with a multiple-CCD camera is used for cycle-resolved imaging in spark-ignition, direct-injection stratified-charge, and homogeneous-charge compression-ignition engines. The recorded data reveal unique information on cycle-to-cycle variations in fuel transport and combustion. Moreover, the imaging system in combination with a scanning mirror is used to perform instantaneous three-dimensional fuel-concentration measurements.

Burden of stroke in Cambodia.

Science.gov (United States)

Loo, Keat Wei; Gan, Siew Hua

2013-08-01

In Cambodia, stroke is not ranked among the top 10 leading causes of death, but infectious disease are among the top three leading causes of death. This finding could be attributed to a lack of awareness among Cambodians of the signs and symptoms of stroke or to poor reporting, incomplete data, lack of neurologists and neurosurgeons, or low accessibility to the hospitals. The only study of stroke in Cambodia is the Prevalence of Non-Communicable Disease Risk Factors in Cambodia survey, which identified several stroke-related risk factors in the population. Tobacco chewing or smoking is the main risk factor for stroke in Cambodia. Traditional therapies, such as oyt pleung (moxibustion) and jup (cupping), are widely practiced for stroke rehabilitation. In Cambodia, there are few neurologists and few important equipment, such as magnetic resonance imaging machines and computed tomography scanners. The Cambodian government should cooperate with the World Health Organization and the United Nations Children's Fund to attract foreign expertise and technologies to treat stroke patients. © 2012 The Authors. International Journal of Stroke © 2012 World Stroke Organization.

EMISSION AND COMBUSTION CHARACTERISTICS OF DIFFERENT FUELS IN A HCCI ENGINE

Directory of Open Access Journals (Sweden)

S. Sendilvelan

2011-06-01

Full Text Available Different intake valve timings and fuel injection amounts were tested in order to identify their effects on exhaust emissions and combustion characteristics using variable valve actuation (VVA in a Homogeneous Charge Compression Ignition (HCCI engine. The HCCI engine is a promising concept for future automobile engines and stationary power plants. The two-stage ignition process in a HCCI engine creates advanced ignition and stratified combustion, which makes the ignition timing and combustion rate controllable. Meanwhile, the periphery of the fuel-rich zone leads to fierce burning, which results in slightly high NOx emissions. The experiments were conducted in a modified single cylinder water-cooled diesel engine. In this experiment we use diesel, bio-diesel (Jatropha and gasoline as the fuel at different mixing ratios. HCCI has advantages in high thermal efficiency and low emissions and could possibly become a promising combustion method in internal combustion engines.

Thermal and dynamic loads on the EPR containment due to hydrogen combustion

International Nuclear Information System (INIS)

Eyink, J.; Movahed, M.; Petzold, K.G.; Kotchourko, A.; Royl, P.; Travis, J.R.

2001-01-01

A major aspect of the EPR safety concept is to cope with severe accidents including core melt and to maintain the integrity of the containment even for those hypothetical events. One potential threat for the containment is related to the combustion of hydrogen, which may be produced in a large amount during core degradation. The European Pressurized Water Reactor (EPR) hydrogen mitigation concept consists of about 44 recombiners, located mainly in the equipment rooms (only 4 recombiners are located in the dome area). This paper is devoted to two important potential threats on the containment related to hydrogen removal: - Thermal loads resulting from recombiner action and/or combustion are of importance also with respect to the integrity of the local composite liner foreseen at some crucial locations of the containment; - Dynamic loads resulting from fast deflagration may impair containment wall or internal walls even if the AICC (adiabatic isochoric complete combustion) pressure is below the design pressure. Two types of combustion calculations have been performed: a) In cases, where fast deflagration cannot be excluded, combustion has been calculated with COM3D, a special CFD code developed to calculate dynamic pressure loads on walls, and b) 'Standing flame' combustion as well as recombination processes have been calculated with GASFLOW for bounding scenarios in order to evaluate maximum containment wall surface temperatures for cases of long-lasting combustion, mainly with emphasis on the application of a partial liner. Because of the depressurization of the reactor coolant system directly into the containment atmosphere via a relief tank and rupture discs a high concentration of steam is available for nearly all scenarios. For these scenarios no threat to internal walls is expected based on the combustion loads identified by the analyses presented here. In case of fast secondary cool-down a large amount of energy is removed to the secondary side of the SG and

A systematic review of perceived barriers and motivators to physical activity after stroke.

Science.gov (United States)

Nicholson, Sarah; Sniehotta, Falko F; van Wijck, Frederike; Greig, Carolyn A; Johnston, Marie; McMurdo, Marion E T; Dennis, Martin; Mead, Gillian E

2013-07-01

Physical fitness is impaired after stroke, may contribute to disability, yet is amenable to improvement through regular physical activity. To facilitate uptake and maintenance of physical activity, it is essential to understand stroke survivors' perceived barriers and motivators. Therefore, we undertook a systematic review of perceived barriers and motivators to physical activity after stroke. Electronic searches of EMBASE, Medline, CINAHL, and PsychInfo were performed. We included peer-reviewed journal articles, in English, between 1 January 1966 and 30 August 2010 reporting stroke survivors' perceived barriers and motivators to physical activity. Searches identified 73,807 citations of which 57 full articles were retrieved. Six articles were included, providing data on 174 stroke survivors (range 10 to 83 per article). Two reported barriers and motivators, two reported only motivators, and two reported only barriers. Five were qualitative articles and one was quantitative. The most commonly reported barriers were lack of motivation, environmental factors (e.g. transport), health concerns, and stroke impairments. The most commonly reported motivators were social support and the need to be able to perform daily tasks. This review has furthered our understanding of the perceived barriers and motivators to physical activity after a stroke. This review will enable the development of tailored interventions to target barriers, while building upon perceived motivators to increase and maintain stroke survivors' physical activity. © 2012 The Authors. International Journal of Stroke © 2012 World Stroke Organization.

Two-stroke engine with gaseous and liquid fuel injection

Energy Technology Data Exchange (ETDEWEB)

Laursen, Rene Sejer [MAN Diesel and Turbo SE, Copenhagen (Denmark)

2012-08-15

The need to lower emissions of CO{sub 2}, NO{sub x}, SO{sub x} and particulates as well as rising oil prices have increased engine operators' interest in alternative fuels and fuel flexibility. The low speed two-stroke ME-GI and ME-LGI dual-fuel engines with diesel pilot injection from MAN Diesel and Turbo offer the opportunity of utilising fuels such as LNG, LPG, and methanol in a wide range of liquid to gaseous fuel ratios. (orig.)

Proceedings of IEA combustion 2009 : IEA 31. task leaders meeting on energy conservation and emissions reduction in combustion

International Nuclear Information System (INIS)

2009-01-01

The International Energy Agency (IEA) supports research and development in energy technology. This meeting provided a forum to discuss combustion processes, which is fundamental to achieving further improvements in fuel use efficiency, reducing the production of pollutants such as nitrogen oxides, and facilitating the transition to alternative fuels. The presentations demonstrated recent studies in improving the efficiency and fuel flexibility of automotive engines; improving the performance of industrial furnaces; emissions formation and control mechanisms; and fuel injection and fuel/air mixing. The conference also highlighted studies involving hydrogen combustion, alternative fuels, particulate diagnostics, fuel sprays, gas turbines, and advanced combustion processes such as homogeneous charge compression ignition (HCCI). The sessions were entitled: HCCI fuels; sprays; nanoparticle diagnostics; alternative fuels; hydrogen internal combustion engines; turbines; energy security; and collaborative task planning. All 45 presentations from the conference have been catalogued separately for inclusion in this database. refs., tabs., figs.

Transient flow combustion

Science.gov (United States)

Tacina, R. R.

1984-01-01

Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

Molten salt combustion of radioactive wastes

International Nuclear Information System (INIS)

Grantham, L.F.; McKenzie, D.E.; Richards, W.L.; Oldenkamp, R.D.

1976-01-01

The Atomics International Molten Salt Combustion Process reduces the weight and volume of combustible β-γ contaminated transuranic waste by utilizing air in a molten salt medium to combust organic materials, to trap particulates, and to react chemically with any acidic gases produced during combustion. Typically, incomplete combustion products such as hydrocarbons and carbon monoxide are below detection limits (i.e., 3 ) is directly related to the sodium chloride vapor pressure of the melt; >80% of the particulate is sodium chloride. Essentially all metal oxides (combustion ash) are retained in the melt, e.g., >99.9% of the plutonium, >99.6% of the europium, and >99.9% of the ruthenium are retained in the melt. Both bench-scale radioactive and pilot scale (50 kg/hr) nonradioactive combustion tests have been completed with essentially the same results. Design of three combustors for industrial applications are underway

Scale Effects on Solid Rocket Combustion Instability Behaviour

OpenAIRE

David R. Greatrix

2011-01-01

The ability to understand and predict the expected internal behaviour of a given solid-propellant rocket motor under transient conditions is important. Research towards predicting and quantifying undesirable transient axial combustion instability symptoms necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. A numerical model incorporating pertinent elements, such as a representative transient, frequency-dependent combusti...

Does national expenditure on research and development influence stroke outcomes?

Science.gov (United States)

Kim, Young Dae; Jung, Yo Han; Norrving, Bo; Ovbiagele, Bruce; Saposnik, Gustavo

2017-10-01

Background Expenditure on research and development is a macroeconomic indicator representative of national investment. International organizations use this indicator to compare international research and development activities. Aim We investigated whether differences in expenditures on research and development at the country level may influence the incidence of stroke and stroke mortality. Methods We compared stroke metrics with absolute amount of gross domestic expenditure on R&D (GERD) per-capita adjusted for purchasing power parity (aGERD) and relative amount of GERD as percent of gross domestic product (rGERD). Sources included official data from the UNESCO, the World Health Organization, the World Bank, and population-based studies. We used correlation analysis and multivariable linear regression modeling. Results Overall, data on stroke mortality rate and GERD were available from 66 countries for two periods (2002 and 2008). Age-standardized stroke mortality rate was associated with aGERD (r = -0.708 in 2002 and r = -0.730 in 2008) or rGERD (r = -0.545 in 2002 and r = -0.657 in 2008) (all p < 0.001). Multivariable analysis showed a lower aGERD and rGERD were independently and inversely associated with higher stroke mortality (all p < 0.05). The estimated prevalence of hypertension, diabetes, or obesity was higher in countries with lower aGERD. The analysis of 27 population-based studies showed consistent inverse associations between aGERD or rGERD and incident risk of stroke and 30-day case fatality. Conclusions There is higher stroke mortality among countries with lower expenditures in research and development. While this study does not prove causality, it suggests a potential area to focus efforts to improve global stroke outcomes.

Stroke in Commercial Flights.

Science.gov (United States)

Álvarez-Velasco, Rodrigo; Masjuan, Jaime; DeFelipe, Alicia; Corral, Iñigo; Estévez-Fraga, Carlos; Crespo, Leticia; Alonso-Cánovas, Araceli

2016-04-01

Stroke on board aircraft has been reported in retrospective case series, mainly focusing on economy class stroke syndrome. Data on the actual incidence, pathogenesis, and prognosis of stroke in commercial flights are lacking. A prospective registry was designed to include all consecutive patients referred from an international airport (40 million passengers a year) to our hospital with a diagnosis of ischemic stroke or transient ischemic attack and onset of symptoms during a flight or immediately after landing. Forty-four patients (32 ischemic strokes and 12 transient ischemic attacks) were included over a 76-month period (January 2008 to April 2014). The estimated incidence of stroke was 1 stroke in 35 000 flights. Pathogeneses of stroke or transient ischemic attack were atherothrombotic in 16 (36%), economy class stroke syndrome in 8 (18%), cardioembolic in 7 (16%), arterial dissection in 4 (9%), lacunar stroke in 4 (9%), and undetermined in 5 (12%) patients. Carotid stenosis >70% was found in 12 (27%) of the patients. Overall prognosis was good, and thrombolysis was applied in 44% of the cases. The most common reason for not treating patients who had experienced stroke onset midflight was the delay in reaching the hospital. Only 1 patient with symptom onset during the flight prompted a flight diversion. We found a low incidence of stroke in the setting of air travel. Economy class stroke syndrome and arterial dissection were well represented in our sample. However, the main pathogenesis was atherothrombosis with a high proportion of patients with high carotid stenosis. © 2016 American Heart Association, Inc.

Producer gas production of Indonesian biomass in fixed-bed downdraft gasifier as an alternative fuels for internal combustion engines

Science.gov (United States)

Simanjuntak, J. P.; Lisyanto; Daryanto, E.; Tambunan, B. H.

2018-03-01

downdraft biomass gasification reactors, coupled with reciprocating internal combustion engines (ICE) are a viable technology for small scale heat and power generation. The direct use of producer gas as fuel subtitution in an ICE could be of great interest since Indonesia has significant land area in different forest types that could be used to produce bioenergy and convert forest materials to bioenergy for use in energy production and the versatility of this engine. This paper will look into the aspect of biomass energie as a contributor to energy mix in Indonesia. This work also contains information gathered from numerous previews study on the downdraft gasifier based on experimental or simulation study on the ability of producer gas as fuels for internal combustion engines aplication. All data will be used to complement the preliminary work on biomass gasification using downdraft to produce producer gas and its application to engines.

Multi-stage combustion using nitrogen-enriched air

Science.gov (United States)

Fischer, Larry E.; Anderson, Brian L.

2004-09-14

Multi-stage combustion technology combined with nitrogen-enriched air technology for controlling the combustion temperature and products to extend the maintenance and lifetime cycles of materials in contact with combustion products and to reduce pollutants while maintaining relatively high combustion and thermal cycle efficiencies. The first stage of combustion operates fuel rich where most of the heat of combustion is released by burning it with nitrogen-enriched air. Part of the energy in the combustion gases is used to perform work or to provide heat. The cooled combustion gases are reheated by additional stages of combustion until the last stage is at or near stoichiometric conditions. Additional energy is extracted from each stage to result in relatively high thermal cycle efficiency. The air is enriched with nitrogen using air separation technologies such as diffusion, permeable membrane, absorption, and cryogenics. The combustion method is applicable to many types of combustion equipment, including: boilers, burners, turbines, internal combustion engines, and many types of fuel including hydrogen and carbon-based fuels including methane and coal.

STROKE IN YOUNG ADULTS: A RETROSPECTIVE STUDY OF 68 CASES

Directory of Open Access Journals (Sweden)

M. H. Harirchian

2006-06-01

Full Text Available Numerous etiologies are responsible for cases of stroke in young adults. This study reviews the causes of two types of stroke (ischemic and intracerebral hemorrhage in young adults aged 15 to 40years, admitted to our center (a tertiary care center from 1997 to 2002. The purpose of this study is to determine the relative frequency of causes of stroke in young adults and compare this with published data in the literature. Using the codes 46.0 to 46.8 of the International Classification of Diseases- 10th Edition (ICD-10, cases were identified from the records of the stroke patients admitted in Imam Khomeini Hospital and the data were collected from their files using a comprehensive questionnaire. Forty-two cases of ischemic stroke (62% and 26 cases of intracerebral hemorrhage (38% were identified. The leading cause of ischemic stroke was cardioembolism (38.1%, followed by atherosclerosis in 5 cases (11.9%. Among cardiac causes infarction was attributable to consequences of rheumatic heart disease in 8 cases. In 3 cases a cessation or decrease in dose of warfarin was followed directly by an ischemic stroke. The most leading cause of intracerebral hemorrhage was hypertension (30.8%. Other causes were anticoagulant therapy, intratumoral hemorrhage, aplastic anemia, leukemia, arteriovenous malformations, and chronic active hepatitis. In conclusion, cardioembolism and hypertension were the most leading causes of ischemic and hemorrhagic stroke in young adults admitted in our hospital.

Effects of Scavenging System Configuration on In-Cylinder Air Flow Organization of an Opposed-Piston Two-Stroke Engine

Directory of Open Access Journals (Sweden)

Fukang Ma

2015-06-01

Full Text Available In-cylinder air flow is very important from the point of view of mixture formation and combustion. In this direction, intake chamber structure and piston crown shape play a very crucial role for in-cylinder air pattern of opposed-piston two-stroke (OP2S engines. This study is concerned with the three-dimensional (3D computational fluid dynamics (CFD analysis of in-cylinder air motion coupled with the comparison of predicted results with the zero-dimensional (0D parametric model. Three configurations viz., a flat piston uniform scavenging chamber, a flat piston non-uniform scavenging chamber and a pit piston non-uniform scavenging chamber have been studied. 0D model analysis of in-cylinder air flow is consistent with 3D CFD simulation. It is concluded that a pit piston non-uniform scavenging chamber is the best design from the point of view of tumble ratio, turbulent kinetic energy and turbulent intensity, which play very important roles in imparting proper air motion. Meanwhile a flat piston uniform scavenging chamber can organize a higher swirl ratio and lower tumble ratio which is important to improve the scavenging process.

Effect of using hydrogen in the power and performance of an internal combustion engine

Directory of Open Access Journals (Sweden)

Edwin Tamayo

2016-12-01

Full Text Available This study analyzed the real working parameters of an Otto cycle internal combustion engine, using as fuel hydrogen plus gasoline. Two stoichiometric equations were determined. In the first equation, the reagents are octane and air, in the second equation was added the quantity of 3.86 H2 moles obtained from a hydrogen cell. Two sets of equations, for consumption and power, were determined from the chemical equations, working at the conditions of Quito: altitude 2850 msnm, 72.794 kPa of atmospheric pressure and 300 K of temperature. A single cylinder engine powered with hydrogen plus gasoline was used for getting real data of engine power, using mixtures of air-gasoline and hydrogen; the theoretical power without H2 was 3.91 HP and with H2 5.41 HP, it increased 27.1%, the real power is 3.78 HP without H2 and 4.66 HP with H2, it increased 16.7%. Theoretical fuel consumption is 401.61 g/kWh and addition of H2 is less to 373.52 g/kWh, the actual consumption that indicates the manufacturer is 395 g/kWh.

Cold flow simulation of an internal combustion engine with vertical valves using layering approach

Science.gov (United States)

Martinas, G.; Cupsa, O. S.; Stan, L. C.; Arsenie, A.

2015-11-01

Complying with emission requirements and fuel consumption efficiency are the points which drive any development of internal combustion engine. Refinement of the process of combustion and mixture formation, together with in-cylinder flow refinement, is a requirement, valves and piston bowl and intake exhaust port design optimization is essential. In order to reduce the time for design optimization cycle it is used Computational Fluid Dynamics (CFD). Being time consuming and highly costly caring out of experiment using flow bench testing this methods start to become less utilized. Air motion inside the intake manifold is one of the important factors, which govern the engine performance and emission of multi-cylinder diesel engines. Any cold flow study on IC is targeting the process of identifying and improving the fluid flow inside the ports and the combustion chamber. This is only the base for an optimization process targeting to increase the volume of air accessing the combustion space and to increase the turbulence of the air at the end of the compression stage. One of the first conclusions will be that the valve diameter is a fine tradeoff between the need for a bigger diameter involving a greater mass of air filling the cylinder, and the need of a smaller diameter in order to reduce the blind zone. Here there is room for optimization studies. The relative pressure indicates a suction effect coming from the moving piston. The more the shape of the inlet port is smoother and the diameter of the piston is bigger, the aerodynamic resistance of the geometry will be smaller so that the difference of inlet port pressure and the pressure near to piston face will be smaller. Here again there is enough room for more optimization studies.

[Forensic medical evaluation of a burn injury from combustion of flammable fluids on the human body based on morphological changes in internal organs].

Science.gov (United States)

Khushkadamov, Z K

2009-01-01

The author describes morphological features of splanchnic organs in the patients that suffered an injury from combustion of flammable fluids at the body surface. The burn injury is a specific form of trauma originating from a combination of several injurious factors including thermoinhalation and intoxication with combustion products in the absence of oxygen in the centre of the hot spot. A rather specific combination of morphological changes in internal organs along with results of laboratory studies provides the most reliable criterion for forensic medical diagnosis of burn injuries from combustion of flammable fluids on the human body.

Diesel emission reduction using internal exhaust gas recirculation

Science.gov (United States)

He, Xin [Denver, CO; Durrett, Russell P [Bloomfield Hills, MI

2012-01-24

A method for controlling combustion in a direct-injection diesel engine includes monitoring a crankshaft rotational position of a cylinder of the engine, monitoring an engine load, determining an intake stroke within the cylinder based upon the crankshaft rotational position, and when the engine load is less than a threshold engine load, opening an exhaust valve for the cylinder during a portion of the intake stroke.

The Riks-Stroke story: building a sustainable national register for quality assessment of stroke care.

Science.gov (United States)

Asplund, Kjell; Hulter Åsberg, Kerstin; Appelros, Peter; Bjarne, Daniela; Eriksson, Marie; Johansson, Asa; Jonsson, Fredrik; Norrving, Bo; Stegmayr, Birgitta; Terént, Andreas; Wallin, Sari; Wester, Per-Olov

2011-04-01

Riks-Stroke, the Swedish Stroke Register, is the world's longest-running national stroke quality register (established in 1994) and includes all 76 hospitals in Sweden admitting acute stroke patients. The development and maintenance of this sustainable national register is described. Riks-Stroke includes information on the quality of care during the acute phase, rehabilitation and secondary prevention of stroke, as well as data on community support. Riks-Stroke is unique among stroke quality registers in that patients are followed during the first year after stroke. The data collected describe processes, and medical and patient-reported outcome measurements. The register embraces most of the dimensions of health-care quality (evidence-based, safe, provided in time, distributed fairly and patient oriented). Annually, approximately 25,000 patients are included. In 2009, approximately 320,000 patients had been accumulated (mean age 76-years). The register is estimated to cover 82% of all stroke patients treated in Swedish hospitals. Among critical issues when building a national stroke quality register, the delicate balance between simplicity and comprehensiveness is emphasised. Future developments include direct transfer of data from digital medical records to Riks-Stroke and comprehensive strategies to use the information collected to rapidly implement new evidence-based techniques and to eliminate outdated methods in stroke care. It is possible to establish a sustainable quality register for stroke at the national level covering all hospitals admitting acute stroke patients. Riks-Stroke is fulfilling its main goals to support continuous quality improvement of Swedish stroke services and serve as an instrument for following up national stroke guidelines. © 2010 The Authors. International Journal of Stroke © 2010 World Stroke Organization.

Quantitative measurements of in-cylinder gas composition in a controlled auto-ignition combustion engine

Science.gov (United States)

Zhao, H.; Zhang, S.

2008-01-01

One of the most effective means to achieve controlled auto-ignition (CAI) combustion in a gasoline engine is by the residual gas trapping method. The amount of residual gas and mixture composition have significant effects on the subsequent combustion process and engine emissions. In order to obtain quantitative measurements of in-cylinder residual gas concentration and air/fuel ratio, a spontaneous Raman scattering (SRS) system has been developed recently. The optimized optical SRS setups are presented and discussed. The temperature effect on the SRS measurement is considered and a method has been developed to correct for the overestimated values due to the temperature effect. Simultaneous measurements of O2, H2O, CO2 and fuel were obtained throughout the intake, compression, combustion and expansion strokes. It shows that the SRS can provide valuable data on this process in a CAI combustion engine.

Quantitative measurements of in-cylinder gas composition in a controlled auto-ignition combustion engine

International Nuclear Information System (INIS)