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.

Numerical investigation on the combined effects of varying piston bowl geometries and ramp injection rate-shapes on the combustion characteristics of a kerosene-diesel fueled direct injection compression ignition engine

International Nuclear Information System (INIS)

Tay, Kun Lin; Yang, Wenming; Zhao, Feiyang; Yu, Wenbin; Mohan, Balaji

2017-01-01

Highlights: • Effect of injection rate-shaping on heat-release is significant with less turbulence. • Two peak heat-releases are seen for the shallow-depth re-entrant piston. • Significant combustion phasing occurs with kerosene usage and high turbulence. - Abstract: In this work, the combustion characteristics of a direct injection compression ignition (DICI) engine fueled with kerosene-diesel blends, using different piston bowl geometries together with varying injection rate-shapes were investigated. A total of three combustion bowl geometries, namely the omega combustion chamber (OCC), the shallow-depth combustion chamber (SCC) and the shallow-depth re-entrant combustion chamber (SRCC), were used together with six different ramp injection rate-shapes and pure diesel, kerosene-diesel and pure kerosene fuels. It is seen that the SRCC geometry, which has the shortest throat length, gives the highest turbulence kinetic energy (TKE) and this resulted in two peak heat-releases, with a primary peak heat-release during the premixed combustion phase and a secondary peak heat-release during the mixing-controlled combustion phase. In addition, the SCC geometry gives rather distinct premixed combustion and mixing-controlled combustion phases due to the fact that combustion is predominantly controlled by the injected fuel spray itself because of less turbulence. Also, when kerosene is used in place of diesel, the heat-release during the premixed combustion phase increases and diminishes during the mixing-controlled and late combustion phases. It is interesting to note that the effect of injection rate-shaping on the heat-release rate is more obvious for bowl geometries that generate less TKE. Moreover, bowl geometries that generate higher TKEs as well as fuels with lower viscosities generally give lower carbon monoxide (CO) emissions and higher nitrogen oxide (NO) emissions. More importantly, it is possible to achieve low NO and CO emissions simultaneously by using the

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...

Engine combustion control via fuel reactivity stratification

Science.gov (United States)

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

2013-12-31

A compression ignition engine uses two or more fuel charges having two or more reactivities to control the timing and duration of combustion. In a preferred implementation, a lower-reactivity fuel charge is injected or otherwise introduced into the combustion chamber, preferably sufficiently early that it becomes at least substantially homogeneously dispersed within the chamber before a subsequent injection is made. One or more subsequent injections of higher-reactivity fuel charges are then made, and these preferably distribute the higher-reactivity matter within the lower-reactivity chamber space such that combustion begins in the higher-reactivity regions, and with the lower-reactivity regions following thereafter. By appropriately choose 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).

Effect of Pilot Injection Timings on the Combustion Temperature Distribution in a Single-Cylinder CI Engine Fueled with DME and ULSD

Directory of Open Access Journals (Sweden)

Jeon Joonho

2016-01-01

Full Text Available Many studies of DiMethyl Ether (DME as an alternative fuel in Compression-Ignition (CI engines have been performed. Although diverse DME engine research has been conducted, the investigation of combustion behavior and temperature distribution in the combustion engine has not progressed due to the fact that there is no sooting flame in DME combustion. In order to investigate the combustion characteristics in this study, the KIVA-3 V code was implemented to research various pilot injection strategies on a single-cylinder CI engines with DME and Ultra-Low-Sulfur Diesel (ULSD fuels. The combustion distribution results obtained from the numerical investigation were validated when compared with the measurement of flame temperature behaviors in the experimental approach. This study showed that long intervals between two injection timings enhanced pilot combustion by increasing the ambient pressure and temperature before the start of the main combustion. Different atomization properties between DME and ULSD fuels contributed to the formation of a fuel-air mixture at the nozzle tip and piston lip regions, separately, which strongly affected the temperature distribution of the two fuels. In addition, the pilot injection timing played a vital role in regard to ignition delay and peak combustion temperatures. Exhaust emissions, such as NOx and soot, are related to the local equivalence ratio and temperature in the combustion chamber, also illustrated by the contrary result on a Φ (equivalence ratio – T (temperature map.

Combustion and emission characteristics of a diesel engine with DME as port premixing fuel under different injection timing

International Nuclear Information System (INIS)

Wang, Ying; Zhao, Yuwei; Xiao, Fan; Li, Dongchang

2014-01-01

Highlights: • Combustion and emission of diesel engine with DME as premixing fuel were examined. • Injection timing has profound effect on HRR of diffusive combustion in PCCI engine. • DME introduction drastically influenced HRR of PCCI combustion, especially for HTR. • Effect of injection timing on emission of PCCI engine is similar to that of DICI engine. - Abstract: This work dealt with the combustion and exhaust performance of a DME premixed charge compression ignition diesel engine. With the port premixing DME, the heat-release process was made up of the premixed charge homogeneous charge compression ignition combustion and diffusion combustion. The in-cylinder fuel injection timing and port premixing DME quantity played the important roles in combustion and emission control. They had little impact on the peak position of heat-release rate (HRR) during LTR phase. However, they had great effects on the peak values and the crank-angle positions corresponding to the HRR peaks during HTR and diffusion combustion phase. The peak value of HRR increased and the crank-angle corresponding to the HRR peak advanced with an incremental DME quantity or an early injection during HTR phase. However, the peak value of HRR dropped with an incremental DME quantity or a late injection during the diffusion combustion phase. p max and T max increased with an incremental DME quantity or an early injection. At the fixed direct-injection timing, BSFC decreased slightly with a rise of DME quantity due to CA50 closer to TDC. At a fixed DME quantity, BSFC was lowest when diesel was injected into cylinder at 7°CA BTDC. Moreover, as more DME was aspirated from port, NO x emissions decreased firstly but this decreasing trend ceased later. Smoke reduced, but CO and HC increased with a rise of DME quantity. Meanwhile, like the conventional DICI operation, NO x increased, but smoke, CO and HC declined with an early direct-injection

Effect of Biodiesel Fuel Injection Timing and Venture for Gaseous Fuel Induction on the Performance, Emissions and Combustion Characteristics of Dual Fuel Engine

Directory of Open Access Journals (Sweden)

Mallikarjun Bhovi

2018-02-01

Full Text Available Advancing or retarding pilot fuel injection timing in a diesel engine provided with either conventional mechanical fuel injection (CMFIS or high pressure injection as in common rail fuel injection (CRDI systems can significantly affect its performance and tail pipe emissions. Performance of diesel engine when fueled with various biofuels as well as gaseous fuels tends to vary with subsequent changes in pilot fuel injection timings. Biodiesel derived from rubber seed oil called Rubber Seed Oil Methyl Ester (RuOME and hydrogen (H2 and hydrogen enriched compressed natural gas called (HCNG both being renewable fuels when used in diesel engines modified to operate in dual fuel mode can provide complete replacement for fossil diesel. In the present study, effect of injection timings and venture design for gas mixing on the performance, combustion and emission characteristics of dual fuel engine fitted with both CMFIS and CRDI injection systems and operated on RuOME and HCNG/hydrogen has been investigated. Results showed that high pressure CRDI assisted injection of RuOME with optimized mixing chamber (carburetor for hydrogen induction in dual fuel engine performed improved compared to that with CMFIS. In addition, for the same fuel combinations, CRDI resulted in lower biodiesel consumption, lower carbon monoxide (BSCO and hydrocarbon (BSHC emissions and increased NOx emissions than CMFIS operation.

Experimental investigation and combustion analysis of a direct injection dual-fuel diesel-natural gas engine

Energy Technology Data Exchange (ETDEWEB)

Carlucci, A.P.; De Risi, A.; Laforgia, D.; Naccarato, F. [Department of Engineering for Innovation, University of Salento, CREA, via per Arnesano, 73100 Lecce (Italy)

2008-02-15

A single-cylinder diesel engine has been converted into a dual-fuel engine to operate with natural gas together with a pilot injection of diesel fuel used to ignite the CNG-air charge. The CNG was injected into the intake manifold via a gas injector on purpose designed for this application. The main performance of the gas injector, such as flow coefficient, instantaneous mass flow rate, delay time between electrical signal and opening of the injector, have been characterized by testing the injector in a constant-volume optical vessel. The CNG jet structure has also been characterized by means of shadowgraphy technique. The engine, operating in dual-fuel mode, has been tested on a wide range of operating conditions spanning different values of engine load and speed. For all the tested operating conditions, the effect of CNG and diesel fuel injection pressure, together with the amount of fuel injected during the pilot injection, were analyzed on the combustion development and, as a consequence, on the engine performance, in terms of specific emission levels and fuel consumption. (author)

Combustion characteristics of a gasoline engine with independent intake port injection and direct injection systems for n-butanol and gasoline

International Nuclear Information System (INIS)

He, Bang-Quan; Chen, Xu; Lin, Chang-Lin; Zhao, Hua

2016-01-01

Highlights: • Different injection approaches for n-butanol and gasoline affect combustion events. • High n-butanol percentage in the total energy of fuels improves combustion stability. • N-butanol promotes ignition and shortens combustion duration. • Lean burn increases indicated mean effective pressure at fixed total energy of fuels. • Different fuel injection methods slightly affect indicated mean effective pressure. - Abstract: N-butanol, as a sustainable biofuel, is usually used as a blend with gasoline in spark ignition engines. In this study, the combustion characteristics were investigated on a four-cylinder spark ignition gasoline engine with independent port fuel injection and direct injection systems for n-butanol and gasoline in different operating conditions. The results show that in the case of port fuel injection of n-butanol with direct injection gasoline at a given total energy released in a cycle, indicated mean effective pressure is slightly affected by spark timing at stoichiometry while it changes much more with delayed spark timing in lean burn conditions and is much higher in lean burn conditions compared to stoichiometry at given spark timings. With the increase of n-butanol percentage in a fixed total energy released in a cycle at given spark timings, ignition timing advances, combustion duration shortens, indicated mean effective pressure and indicated thermal efficiency increase. For the cases of port fuel injection of n-butanol with direction injection gasoline and port fuel injection of gasoline with direction injection n-butanol at a fixed total energy released in a cycle, their indicated mean effective pressures are close. But their combustion processes are dependent on fuel injection approaches.

Numerical investigation of the effect of injection strategy on mixture formation and combustion process in a port injection natural gas rotary engine

International Nuclear Information System (INIS)

Fan, Baowei; Pan, Jianfeng; Yang, Wenming; Liu, Yangxian; Bani, Stephen; Chen, Wei

2017-01-01

Highlights: • For injection timing, the fuel movement is controlled by the intensity of the vortex I. • For injection duration, the fuel movement is controlled by the value of jet flux. • The ideal fuel distribution at ignition timing for high combustion rate is studied. • The optimal injection strategy had an increase in the peak pressure and NO emissions. - Abstract: This work aimed to numerically study the influence of injection strategy on mixture formation and combustion process in a port injection natural gas rotary engine. On the base of a 3D dynamic simulation model which was established in our previous work, some critical information was obtained, which was difficult to obtain through experiment, in terms of the flow field, the fuel distribution, the temperature field and the concentration fields of some intermediates. Simulation results showed that for mixture formation, the movements of fuel in injection stage were mainly controlled by the intensity of the vortex I for injection timing, and the value of jet flux for injection duration respectively. With retarded injection timing, the decreasing intensity of the vortex I resulted in less fuel moving toward the back of the combustion chamber. With the extension in injection duration, the decreasing value of jet flux resulted in more fuel staying at the back of the combustion chamber. For combustion process, the overall combustion rate for injection strategy which had an injection timing of 390 °CA (BTDC) and injection duration of 51.5 °CA (case ID4) was the fastest. This was mainly due to the fact that the accumulation area of fuel was at the middle and front of the combustion chamber. Meanwhile, fuel concentration near the leading and trailing spark plugs was conducive for the flame kernel formation. Compared with the injection strategy which had an injection timing of 450 °CA (BTDC) and an injection duration of 55 °CA (case IT1), the improved combustion rate of case ID4 had a 23% increase in

Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels

International Nuclear Information System (INIS)

Benajes, Jesús; Molina, Santiago; García, Antonio; Monsalve-Serrano, Javier

2015-01-01

Highlights: • E85 requires notable lower premixed energy ratios to achieve a stable combustion. • E10-95 leads to shorter and advanced combustion with higher maximum RoHR peaks. • E20-95, E10-98 and E10-95 reach EURO VI NOx and soot levels for all the engine loads. • E10-95 allows a significant reduction in HC and CO emissions. - Abstract: This work investigates the effects of the direct injection timing and blending ratio on RCCI performance and engine-out emissions at different engine loads using four low reactivity fuels: E10-95, E10-98, E20-95 and E85 (port fuel injected) and keeping constant the same high reactivity fuel: diesel B7 (direct injected). The experiments were conducted using a heavy-duty single-cylinder research diesel engine adapted for dual-fuel operation. All the tests were carried out at 1200 rpm. To assess the blending ratio effect, the total energy delivered to the cylinder coming from the low reactivity fuel was kept constant for the different fuel blends investigated by adjusting the low reactivity fuel mass as required in each case. In addition, a detailed analysis of the air/fuel mixing process has been developed by means of a 1-D in-house developed spray model. Results suggest that notable higher diesel amount is required to achieve a stable combustion using E85. This fact leads to higher NOx levels and unacceptable ringing intensity. By contrast, EURO VI NOx and soot levels are fulfilled with E20-95, E10-98 and E10-95. Finally, the higher reactivity of E10-95 results in a significant reduction in CO and HC emissions, mainly at low load

Effects of port fuel injection (PFI) of n-butanol and EGR on combustion and emissions of a direct injection diesel engine

International Nuclear Information System (INIS)

Chen, Zheng; Liu, Jingping; Wu, Zhenkuo; Lee, Chiafon

2013-01-01

Highlights: • A DI diesel engine with PFI of n-butanol in combination with EGR is investigated. • Butanol concentration and EGR have a coupled impact on combustion process. • A combination of butanol PFI and EGR can break through tradeoff between NOx and soot. • DI diesel with butanol PFI has lower ITE than DI of diesel–butanol blends. - Abstract: An experimental investigation was conducted on a direct injection (DI) diesel engine with exhaust gas recirculation (EGR), coupled with port fuel injection (PFI) of n-butanol. Effects of butanol concentration and EGR rate on combustion, efficiency, and emissions of the tested engine were evaluated, and also compared to a DI mode of diesel–butanol blended fuel. The results show butanol concentration and EGR rate have a coupled impact on combustion process. Under low EGR rate condition, both the peak cylinder pressure and the peak heat release rate increase with increased butanol concentration, but no visible influence was found on the ignition delay. Under high EGR rate condition, however, the peak cylinder pressure and the peak heat release rate both decrease with increased butanol concentration, accompanied by longer ignition delay and longer combustion duration. As regard to the regulated emissions, HC and CO emissions increase with increased butanol concentration, causing higher indicated specific fuel consumption (ISFC) and lower indicated thermal efficiency (ITE). It is also noted that butanol PFI in combination with EGR can change the trade-off relationship between NOx and soot, and simultaneously reduce both into a very low level. Compared with the DI mode of diesel–butanol blended fuel, however, the DI diesel engine with butanol PFI has higher HC and CO emissions and lower ITE. Therefore, future research should be focused on overcoming the identified shortcomings by an improved injection strategy of butanol PFI

Diesel/CNG Mixture Autoignition Control Using Fuel Composition and Injection Gap

Directory of Open Access Journals (Sweden)

Firmansyah

2017-10-01

Full Text Available Combustion phasing is the main obstacle to the development of controlled auto-ignition based (CAI engines to achieve low emissions and low fuel consumption operation. Fuel combinations with substantial differences in reactivity, such as diesel/compressed natural gas (CNG, show desirable combustion outputs and demonstrate great possibility in controlling the combustion. This paper discusses a control method for diesel/CNG mixture combustion with a variation of fuel composition and fuel stratification levels. The experiments were carried out in a constant volume combustion chamber with both fuels directly injected into the chamber. The mixture composition was varied from 0 to 100% CNG/diesel at lambda 1 while the fuel stratification level was controlled by the injection phasing between the two fuels, with gaps between injections ranging from 0 to 20 ms. The results demonstrated the suppressing effect of CNG on the diesel combustion, especially at the early combustion stages. However, CNG significantly enhanced the combustion performance of the diesel in the later stages. Injection gaps, on the other hand, showed particular behavior depending on mixture composition. Injection gaps show less effect on combustion phasing but a significant effect on the combustion output for higher diesel percentage (≥70%, while it is contradictive for lower diesel percentage (<70%.

Numerical Simulations of Hollow Cone Injection and Gasoline Compression Ignition Combustion With Naphtha Fuels

KAUST Repository

Badra, Jihad A.

2016-01-11

Gasoline compression ignition (GCI), also known as partially premixed compression ignition (PPCI) and gasoline direct injection compression ignition (GDICI), engines have been considered an attractive alternative to traditional spark ignition engines. Lean burn combustion with the direct injection of fuel eliminates throttle losses for higher thermodynamic efficiencies, and the precise control of the mixture compositions allows better emission performance such as NOx and particulate matter (PM). Recently, low octane gasoline fuel has been identified as a viable option for the GCI engine applications due to its longer ignition delay characteristics compared to diesel and lighter evaporation compared to gasoline fuel [1]. The feasibility of such a concept has been demonstrated by experimental investigations at Saudi Aramco [1, 2]. The present study aims to develop predictive capabilities for low octane gasoline fuel compression ignition engines with accurate characterization of the spray dynamics and combustion processes. Full three-dimensional simulations were conducted using CONVERGE as a basic modeling framework, using Reynolds-averaged Navier-Stokes (RANS) turbulent mixing models. An outwardly opening hollow-cone spray injector was characterized and validated against existing and new experimental data. An emphasis was made on the spray penetration characteristics. Various spray breakup and collision models have been tested and compared with the experimental data. An optimum combination has been identified and applied in the combusting GCI simulations. Linear instability sheet atomization (LISA) breakup model and modified Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) break models proved to work the best for the investigated injector. Comparisons between various existing spray models and a parametric study have been carried out to study the effects of various spray parameters. The fuel effects have been tested by using three different primary reference fuel (PRF

Numerical Investigation Into Effect of Fuel Injection Timing on CAI/HCCI Combustion in a Four-Stroke GDI Engine

Science.gov (United States)

Cao, Li; Zhao, Hua; Jiang, Xi; Kalian, Navin

2006-02-01

The Controlled Auto-Ignition (CAI) combustion, also known as Homogeneous Charge Compression Ignition (HCCI), was achieved by trapping residuals with early exhaust valve closure in conjunction with direct injection. Multi-cycle 3D engine simulations have been carried out for parametric study on four different injection timings in order to better understand the effects of injection timings on in-cylinder mixing and CAI combustion. The full engine cycle simulation including complete gas exchange and combustion processes was carried out over several cycles in order to obtain the stable cycle for analysis. The combustion models used in the present study are the Shell auto-ignition model and the characteristic-time combustion model, which were modified to take the high level of EGR into consideration. A liquid sheet breakup spray model was used for the droplet breakup processes. The analyses show that the injection timing plays an important role in affecting the in-cylinder air/fuel mixing and mixture temperature, which in turn affects the CAI combustion and engine performance.

Experimental investigation concerning the influence of fuel type and properties on the injection and atomization of liquid biofuels in an optical combustion chamber

International Nuclear Information System (INIS)

Galle, J.; Defruyt, S.; Van de Maele, C.; Rodriguez, R. Piloto; Denon, Q.; Verliefde, A.; Verhelst, S.

2013-01-01

Due to the scarcity of fossil fuels and the future stringent emission limits, there is an increasing interest for the use of renewable biofuels in compression ignition engines. However, these fuels have different physical, chemical and thermodynamic properties affecting atomization, spray development and combustion processes. The results reported in this paper have been obtained by experimentation with a constant volume combustion chamber. The influences of physical fuel properties on injections under non-evaporating conditions are studied, using a pump-line-nozzle system from a medium speed diesel engine with injection pressures up to 1200 bar, by changing the fuel type and temperature. Experiments were conducted for diesel, biodiesel, straight vegetable oils and animal fats. Injection pressure and needle lift measurements were analyzed. A high speed camera was used to visualize the spray, which enabled us to study the spray penetration and spray angle. Our results show that the fuel temperature is an important parameter to control because it significantly affects the fuel properties. Both the injection timing and injection duration are affected by the fuel properties. The influences of these properties on the spray development were less pronounced. At low temperatures, a strongly deteriorated atomization of oils and fats was observed. -- Highlights: • Spray measurements in an optical combustion chamber. • Influence on the injections system is compared for different bio-fuels. •Temperature effects the fuel properties, with strong influence on the injection system. • Viscosity has significant influence on atomization, especially for viscous fuels. • No difference for spray penetration and angle unlike the mass distribution

Fueling an D.I. agricultural diesel engine with waste oil biodiesel: Effects over injection, combustion and engine characteristics

International Nuclear Information System (INIS)

Radu, Rosca; Petru, Carlescu; Edward, Rakosi; Gheorghe, Manolache

2009-01-01

The paper presents the results of a research concerning the use of a biodiesel type fuel in D.I. Diesel engine; the fuel injection system and the engine were tested. The results indicated that the injection characteristics are affected when a blend containing 50% methyl ester and 50% petrodiesel is used as fuel (injection duration, pressure wave propagation time, average injection rate, peak injection pressure). As a result, the engine characteristics are also affected, the use of the biodiesel blend leading to lower output power and torque; the lower autoignition delay and pressure wave propagation time led to changes of the cylinder pressure and heat release traces and to lower peak combustion pressures.

Effect of the Ethanol Injection Moment During Compression Stroke on the Combustion of Ethanol - Diesel Dual Direct Injection Engine

Science.gov (United States)

Liang, Yu; Zhou, Liying; Huang, Haomin; Xu, Mingfei; Guo, Mei; Chen, Xin

2018-01-01

A set of GDI system is installed on a F188 single-cylinder, air-cooled and direct injection diesel engine, which is used for ethanol injection, with the injection time controlled by the crank angle signal collected by AVL angle encoder. The injection of ethanol amounts to half of the thermal equivalent of an original diesel fuel. A 3D combustion model is established for the ethanol - diesel dual direct injection engine. Diesel was injected from the original fuel injection system, with a fuel supply advance angle of 20°CA. The ethanol was injected into the cylinder during compression process. Diesel injection began after the completion of ethanol injection. Ethanol injection starting point of 240°CA, 260°CA, 280°CA, 300°CA and 319.4°CA were simulated and analyzed. Due to the different timing of ethanol injection, the ignition of the ethanol mixture when diesel fires, results in non-uniform ignition distribution and flame propagation rate, since the distribution and concentration gradients of the ethanol mixture in the cylinder are different, thus affecting the combustion process. The results show that, when ethanol is injected at 319.4°CA, the combustion heat release rate and the pressure rise rate during the initial stage are the highest. Also, the maximum combustion pressure, with a relatively advance phase, is the highest. In case of later initial ethanol injection, the average temperature in the cylinder during the initial combustion period will have a faster rise. In case of initial injection at 319.4°CA, the average temperature in the cylinder is the highest, followed by 240°CA ethanol injection. In the post-combustion stage, the earlier ethanol injection will result in higher average temperature in the cylinder and more complete fuel combustion. The injection of ethanol at 319.4°CA produces earlier and highest NOX emissions.

MODELING OF FUEL SPRAY CHARACTERISTICS AND DIESEL COMBUSTION CHAMBER PARAMETERS

Directory of Open Access Journals (Sweden)

G. M. Kukharonak

2011-01-01

Full Text Available The computer model for coordination of fuel spray characteristics with diesel combustion chamber parameters has been created in the paper.  The model allows to observe fuel sprays  develоpment in diesel cylinder at any moment of injection, to calculate characteristics of fuel sprays with due account of a shape and dimensions of a combustion chamber, timely to change fuel injection characteristics and supercharging parameters, shape and dimensions of a combustion chamber. Moreover the computer model permits to determine parameters of holes in an injector nozzle that provides the required fuel sprays characteristics at the stage of designing a diesel engine. Combustion chamber parameters for 4ЧН11/12.5 diesel engine have been determined in the paper.

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

KAUST Repository

Jing, Wei

2016-12-01

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement was implemented by two-color pyrometry under quiescent type diesel engine conditions (1000 K and 21% O2 concentration). Different fuel quantities, which correspond to different injection widths from 0.5 ms to 2 ms under constant injection pressure (1000 bar), were used to simulate different loads in engines. For a given fuel, soot temperature and KL factor show a different trend at initial stage for different fuel quantities, where a higher soot temperature can be found in a small fuel quantity case but a higher KL factor is observed in a large fuel quantity case generally. Another difference occurs at the end of combustion due to the termination of fuel injection. Additionally, BTL flame has a lower soot temperature, especially under a larger fuel quantity (2 ms injection width). Meanwhile, average soot level is lower for BTL flame, especially under a lower fuel quantity (0.5 ms injection width). BTL shows an overall low sooting behavior with low soot temperature compared to diesel, however, trade-off between soot level and soot temperature needs to be carefully selected when different loads are used.

On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

KAUST Repository

Naser, Nimal

2017-06-29

A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of

On the effects of fuel properties and injection timing in partially premixed compression ignition of low octane fuels

KAUST Repository

Naser, Nimal; Jaasim, Mohammed; Atef, Nour; Chung, Suk-Ho; Im, Hong G.; Sarathy, Mani

2017-01-01

A better understanding on the effects of fuel properties and injection timing is required to improve the performance of advanced engines based on low temperature combustion concepts. In this work, an experimental and computational study was conducted to investigate the effects of physical and chemical kinetic properties of low octane fuels and their surrogates in partially premixed compression ignition (PPCI) engines. The main objective was to identify the relative importance of physical versus chemical kinetic properties in predicting practical fuel combustion behavior across a range of injection timings. Two fuel/surrogate pairs were chosen for comparison: light naphtha (LN) versus the primary reference fuel (PRF) with research octane number of 65 (PRF 65), and FACE (fuels for advanced combustion engines) I gasoline versus PRF 70. Two sets of parametric studies were conducted: the first varied the amount of injected fuel mass at different injection timings to match a fixed combustion phasing, and the second maintained the same injected fuel mass at each injection timing to assess resulting combustion phasing changes. Full-cycle computational fluid dynamic engine simulations were conducted by accounting for differences in the physical properties of the original and surrogate fuels, while employing identical chemical kinetics. The simulations were found to capture trends observed in the experiments, while providing details on spatial mixing and chemical reactivity for different fuels and injection timings. It was found that differences in physical properties become increasingly important as injection timing was progressively delayed from premixed conditions, and this was rationalized by analysis of mixture stratification patterns resulting from injection of fuels with different physical properties. The results suggest that accurate descriptions of both physical and chemical behavior of fuels are critical in predictive simulations of PPCI engines for a wide range of

Effects of Fuel Quantity on Soot Formation Process for Biomass-Based Renewable Diesel Fuel Combustion

KAUST Repository

Jing, Wei; Wu, Zengyang; Roberts, William L.; Fang, Tiegang

2016-01-01

Soot formation process was investigated for biomass-based renewable diesel fuel, such as biomass to liquid (BTL), and conventional diesel combustion under varied fuel quantities injected into a constant volume combustion chamber. Soot measurement

Numerical Studies on Controlling Gaseous Fuel Combustion by Managing the Combustion Process of Diesel Pilot Dose in a Dual-Fuel Engine

Directory of Open Access Journals (Sweden)

Mikulski Maciej

2015-06-01

Full Text Available Protection of the environment and counteracting global warming require finding alternative sources of energy. One of the methods of generating energy from environmentally friendly sources is increasing the share of gaseous fuels in the total energy balance. The use of these fuels in compression-ignition (CI engines is difficult due to their relatively high autoignition temperature. One solution for using these fuels in CI engines is operating in a dualfuel mode, where the air and gas mixture is ignited with a liquid fuel dose. In this method, a series of relatively complex chemical processes occur in the engine's combustion chamber, related to the combustion of individual fuel fractions that interact with one another. Analysis of combustion of specific fuels in this type of fuel injection to the engine is difficult due to the fact that combustion of both fuel fractions takes place simultaneously. Simulation experiments can be used to analyse the impact of diesel fuel combustion on gaseous fuel combustion. In this paper, we discuss the results of simulation tests of combustion, based on the proprietary multiphase model of a dual-fuel engine. The results obtained from the simulation allow for analysis of the combustion process of individual fuels separately, which expands the knowledge obtained from experimental tests on the engine.

Effects of Pilot Injection Timing and EGR on Combustion, Performance and Exhaust Emissions in a Common Rail Diesel Engine Fueled with a Canola Oil Biodiesel-Diesel Blend

Directory of Open Access Journals (Sweden)

Jun Cong Ge

2015-07-01

Full Text Available Biodiesel as a clean energy source could reduce environmental pollution compared to fossil fuel, so it is becoming increasingly important. In this study, we investigated the effects of different pilot injection timings from before top dead center (BTDC and exhaust gas recirculation (EGR on combustion, engine performance, and exhaust emission characteristics in a common rail diesel engine fueled with canola oil biodiesel-diesel (BD blend. The pilot injection timing and EGR rate were changed at an engine speed of 2000 rpm fueled with BD20 (20 vol % canola oil and 80 vol % diesel fuel blend. As the injection timing advanced, the combustion pressure, brake specific fuel consumption (BSFC, and peak combustion pressure (Pmax changed slightly. Carbon monoxide (CO and particulate matter (PM emissions clearly decreased at BTDC 20° compared with BTDC 5°, but nitrogen oxide (NOx emissions increased slightly. With an increasing EGR rate, the combustion pressure and indicated mean effective pressure (IMEP decreased slightly at BTDC 20° compared to other injection timings. However, the Pmax showed a remarkable decrease. The BSFC and PM emissions increased slightly, but the NOx emission decreased considerably.

Ducted combustion chamber for direct injection engines and method

Science.gov (United States)

Mueller, Charles

2015-03-03

An internal combustion engine includes an engine block having a cylinder bore and a cylinder head having a flame deck surface disposed at one end of the cylinder bore. A piston connected to a rotatable crankshaft and configured to reciprocate within the cylinder bore has a piston crown portion facing the flame deck surface such that a combustion chamber is defined within the cylinder bore and between the piston crown and the flame deck surface. A fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber has at least one nozzle opening configured to inject a fuel jet into the combustion chamber along a fuel jet centerline. At least one duct defined in the combustion chamber between the piston crown and the flame deck surface has a generally rectangular cross section and extends in a radial direction relative to the cylinder bore substantially along the fuel jet centerline.

Development of High Efficiency and Low Emission Low Temperature Combustion Diesel Engine with Direct EGR Injection

Science.gov (United States)

Ho, R. J.; Kumaran, P.; Yusoff, M. Z.

2016-03-01

Focus on energy and environmental sustainability policy has put automotive research & development directed to developing high efficiency and low pollutant power train. Diffused flame controlled diesel combustion has reach its limitation and has driven R&D to explore other modes of combustions. Known effective mode of combustion to reduce emission are Low temperature combustion (LTC) and homogeneous charge combustion ignition by suppressing Nitrogen Oxide(NOx) and Particulate Matter (PM) formation. The key control to meet this requirement are chemical composition and distribution of fuel and gas during a combustion process. Most research to accomplish this goal is done by manipulating injected mass flow rate and varying indirect EGR through intake manifold. This research paper shows viable alternative direct combustion control via co-axial direct EGR injection with fuel injection process. A simulation study with OpenFOAM is conducted by varying EGR injection velocity and direct EGR injector diameter performed with under two conditions with non-combustion and combustion. n-heptane (C7H16) is used as surrogate fuel together with 57 species 290 semi-detailed chemical kinetic model developed by Chalmers University is used for combustion simulation. Simulation result indicates viability of co-axial EGR injection as a method for low temperature combustion control.

Low-Temperature Combustion of High Octane Fuels in a Gasoline Compression Ignition Engine

Directory of Open Access Journals (Sweden)

Khanh Duc Cung

2017-12-01

Full Text Available Gasoline compression ignition (GCI has been shown as one of the advanced combustion concepts that could potentially provide a pathway to achieve cleaner and more efficient combustion engines. Fuel and air in GCI are not fully premixed compared to homogeneous charge compression ignition (HCCI, which is a completely kinetic-controlled combustion system. Therefore, the combustion phasing can be controlled by the time of injection, usually postinjection in a multiple-injection scheme, to mitigate combustion noise. Gasoline usually has longer ignition delay than diesel. The autoignition quality of gasoline can be indicated by research octane number (RON. Fuels with high octane tend to have more resistance to autoignition, hence more time for fuel-air mixing. In this study, three fuels, namely, aromatic, alkylate, and E30, with similar RON value of 98 but different hydrocarbon compositions were tested in a multicylinder engine under GCI combustion mode. Considerations of exhaust gas recirculating (EGR, start of injection, and boost were investigated to study the sensitivity of dilution, local stratification, and reactivity of the charge, respectively, for each fuel. Combustion phasing (location of 50% of fuel mass burned was kept constant during the experiments. This provides similar thermodynamic conditions to study the effect of fuels on emissions. Emission characteristics at different levels of EGR and lambda were revealed for all fuels with E30 having the lowest filter smoke number and was also most sensitive to the change in dilution. Reasonably low combustion noise (<90 dB and stable combustion (coefficient of variance of indicated mean effective pressure <3% were maintained during the experiments. The second part of this article contains visualization of the combustion process obtained from endoscope imaging for each fuel at selected conditions. Soot radiation signal from GCI combustion were strong during late injection and also more intense

Optimization of combustion chamber geometry and operating conditions for compression ignition engine fueled with pre-blended gasoline-diesel fuel

International Nuclear Information System (INIS)

Lee, Seokhwon; Jeon, Joonho; Park, Sungwook

2016-01-01

Highlights: • Pre-blended gasoline-diesel fuel was used with direct injection system. • KIVA-CHEMKIN code modeled dual-fuel fuel spray and combustion processes with discrete multi-component model. • The characteristics of Combustion and emission on pre-blended fuel was investigated with various fuel reactivities. • Optimization of combustion chamber shape improved combustion performance of the gasoline-diesel blended fuel engine. - Abstract: In this study, experiments and numerical simulations were used to improve the fuel efficiency of compression ignition engine using a gasoline-diesel blended fuel and an optimization technology. The blended fuel is directly injected into the cylinder with various blending ratios. Combustion and emission characteristics were investigated to explore the effects of gasoline ratio on fuel blend. The present study showed that the advantages of gasoline-diesel blended fuel, high thermal efficiency and low emission, were maximized using the numerical optimization method. The ignition delay and maximum pressure rise rate increased with the proportion of gasoline. As the gasoline fraction increased, the combustion duration and the indicated mean effective pressure decreased. The homogeneity of the fuel-air mixture was improved due to longer ignition delay. Soot emission was significantly reduced up to 90% compared to that of conventional diesel. The nitrogen oxides emissions of the blended fuel increased slightly when the start of injection was retarded toward top dead center. For the numerical study, KIVA-CHEMKIN multi-dimensional CFD code was used to model the combustion and emission characteristics of gasoline-diesel blended fuel. The micro genetic algorithm coupled with the KIVA-CHEMKIN code were used to optimize the combustion chamber shape and operating conditions to improve the combustion performance of the blended fuel engine. The optimized chamber geometry enhanced the fuel efficiency, for a level of nitrogen oxides

Investigation on the effects of pilot injection on low temperature combustion in high-speed diesel engine fueled with n-butanol–diesel blends

International Nuclear Information System (INIS)

Huang, Haozhong; Liu, Qingsheng; Yang, Ruzhi; Zhu, Tianru; Zhao, Ruiqing; Wang, Yaodong

2015-01-01

Highlights: • The effects of pre-injected timing and pre-injected mass were studied in CI engine. • The addition of n-butanol consumed OH free radicals, which delayed the ignition time. • With the increase of n-butanol, the BSFC and MPRR increased, NO_x and soot decreased. • With the advance of pilot injection timing, the BSFC increased, NO_x and soot decreased. • With the increase of pilot injection mass, NO_x increased, soot decreased then increased. - Abstract: The effect of pilot injection timing and pilot injection mass on combustion and emission characteristics under medium exhaust gas recirculation (EGR (25%)) condition were experimentally investigated in high-speed diesel engine. Diesel fuel (B0), two blends of butanol and diesel fuel denoted as B20 (20% butanol and 80% diesel in volume), and B30 (30% butanol and 70% diesel in volume) were tested. The results show that, for all fuels, when advancing the pilot injection timing, the peak value of heat release rate decreases for pre-injection fuel, but increases slightly for the main-injection fuel. Moreover, the in-cylinder pressure peak value reduces with the rise of maximum pressure rise rate (MPRR), while NO_x and soot emissions reduce. Increasing the pilot injection fuel mass, the peak value of heat release rate for pre-injected fuel increases, but for the main-injection, the peak descends, and the in-cylinder pressure peak value and NO_x emissions increase, while soot emission decreases at first and then increases. Blending n-butanol in diesel improves soot emissions. When pilot injection is adopted, the increase of n-butanol ratio causes the MPRR increasing and the crank angle location for 50% cumulative heat release (CA50) advancing, as well as NO_x and soot emissions decreasing. The simulation of the combustion of n-butanol–diesel fuel blends, which was based on the n-heptane–n-butanol–PAH–toluene mixing mechanism, demonstrated that the addition of n-butanol consumed OH free radicals

Performance and combustion analysis of Mahua biodiesel on a single cylinder compression ignition engine using electronic fuel injection system

Directory of Open Access Journals (Sweden)

Gunasekaran Anandkumar

2016-01-01

Full Text Available In this investigation, experiment is carried out on a 1500 rpm constant speed single cylinder Diesel engine. The test is carried out with Neat diesel, neat biodiesel, and blend B20. The engine considered was run with electronic fuel injection system supported by common rail direct injection to obtain high atomization and effective air utilization inside the combustion chamber. The performance of the engine in terms of break thermal efficiency and brake specific energy consumption was found and compared. The B20 blend shows 1.11% decrease in break thermal efficiency and 3.35% increase in brake specific energy consumption than diesel. The combustion characteristics found are in-cylinder pressure, rate of pressure rise, and heat release rate and compared for peak pressure load to understand the nature of combustion process. For each fuel test run, the maximum peak pressure is observed at part load condition. The rate of change of pressure and heat release rate of diesel is high compared to pure biodiesel and B20 blend. The diffusion combustion is observed to be predominant in case of B100 than B20 and Neat diesel.

Investigation of Bio-Diesel Fueled Engines under Low-Temperature Combustion Strategies

Energy Technology Data Exchange (ETDEWEB)

Chia-fon F. Lee; Alan C. Hansen

2010-09-30

In accordance with meeting DOE technical targets this research was aimed at developing and optimizing new fuel injection technologies and strategies for the combustion of clean burning renewable fuels in diesel engines. In addition a simultaneous minimum 20% improvement in fuel economy was targeted with the aid of this novel advanced combustion system. Biodiesel and other renewable fuels have unique properties that can be leveraged to reduce emissions and increase engine efficiency. This research is an investigation into the combustion characteristics of biodiesel and its impacts on the performance of a Low Temperature Combustion (LTC) engine, which is a novel engine configuration that incorporates technologies and strategies for simultaneously reducing NOx and particulate emissions while increasing engine efficiency. Generating fundamental knowledge about the properties of biodiesel and blends with petroleum-derived diesel and their impact on in-cylinder fuel atomization and combustion processes was an important initial step to being able to optimize fuel injection strategies as well as introduce new technologies. With the benefit of this knowledge experiments were performed on both optical and metal LTC engines in which combustion and emissions could be observed and measured under realistic conditions. With the aid these experiments and detailed combustion models strategies were identified and applied in order to improve fuel economy and simultaneously reduce emissions.

Effect of main injection timing for controlling the combustion phasing of a homogeneous charge compression ignition engine using a new dual injection strategy

International Nuclear Information System (INIS)

Das, Pranab; Subbarao, P.M.V.; Subrahmanyam, J.P.

2015-01-01

Highlights: • A new dual injection concept is developed by minimum geometry modification. • The occurrence of combustion parameters strongly depend on main injection timing. • At higher load, premixed equivalence ratio dominates over main injection timing. • Retarded of main injection timing tends to retard combustion phasing. • Slightly retarded main injection timing is recommended to avoid intense knocking. - Abstract: Homogeneous charge compression ignition combustion of diesel fuel is implemented using a novel dual injection strategy. A new experimental technique is developed to modify a single cylinder direct injection diesel engine to run on homogeneous combustion mode. Effect of main injection timing is investigated covering a range from 26 to 8 crank angle degrees before top dead center with an interval of 3°. Retarded main injection timing is identified as a control strategy for delaying combustion phasing and a means of controlled combustion phasing of direct injection homogeneous charge compression ignition combustion. Two load conditions were investigated and it was observed that at higher load, start of combustion depends more on fuel air equivalence ratio than main injection timing, whereas at low load, it significantly varies with varying main injection timing. Significant improvements in smoke and oxides of nitrogen emissions are observed when compared with the baseline conventional combustion. By studying different combustion parameters, it is observed that there is an improvement in performance and emissions with marginal loss in thermal efficiency when the main injection timing is 20° before top dead center. This is identified as the optimum main injection timing for such homogeneous combustion under the same operating condition

Experimental study of the effects of natural gas injection timing on the combustion performance and emissions of a turbocharged common rail dual-fuel engine

International Nuclear Information System (INIS)

Yang, Bo; Wei, Xing; Xi, Chengxun; Liu, Yifu; Zeng, Ke; Lai, Ming-Chia

2014-01-01

Highlights: • Natural gas injection timing has obvious effects on combustion of dual-fuel engine. • Combustion performance is improved with optimized natural gas injection timing. • BSHC and BSCO decreased with retarded natural gas injection timing at low load. • BSNO x increased at part load while reduced at high load with delay N.G. injection. • PM is very low and insensitive to the variation of natural gas injection timing. - Abstract: Natural gas combustion with pilot ignition has been considered to be one of the most promising ways to utilize natural gas in existing diesel engine without serious engine modification and it has been widely researched all over the world. In this study, three experiments of different loads (BMEP 0.240 MPa, 0.480 MPa and 0.767 MPa) were performed on a 2.8 L four-cylinder, natural gas manifold injection dual-fuel engine to investigate the effects of natural gas injection timing on engine combustion performance and emissions. The pilot injection parameters (pilot injection timing and pressure) and natural gas injection pressure remain constant at a speed of 1600 rpm in the experiment. The cylinder pressure, HRR, CoV imep , flame development duration, CA50 and brake thermal efficiency were analyzed. The results indicated that under low and part engine loads, the flame development duration and CA50 can be reduced by properly retarding natural gas injection timing, while the CoV imep increased with retarded natural gas injection timing. As a result, the brake thermal efficiency is increased and the combustion stability slightly deteriorates. Meanwhile, under low and part engine loads, PM emissions in the dual-fuel engine is much lower than that in conventional diesel engines, furthermore, at high load, the PM emissions are near zero. CO and HC emissions are reduced with retarded natural gas injection timing under low and part loads, however, NO x emissions are slightly increased. Under high load, the flame development duration

Effects of pilot injection parameters on low temperature combustion diesel engines equipped with solenoid injectors featuring conventional and rate-shaped main injection

International Nuclear Information System (INIS)

D’Ambrosio, S.; Ferrari, A.

2016-01-01

Highlights: • The influence of the principal pilot injection parameters is discussed for low-temperature combustion systems. • Swirl-sweep and dwell-time sweep results are combined to analyze soot emissions. • The pilot injection effects are investigated in injection profiles featuring rate-shaped main injections. - Abstract: The potential of pilot injection has been assessed on a low-temperature combustion diesel engine for automotive applications, which was characterized by a reduced compression-ratio, high EGR rates and postponed main injection timings. Dwell time sweeps have been carried out for pilot injections with distinct energizing times under different representative steady-state working conditions of the medium load and speed area of the New European Driving Cycle. The results of in-cylinder analyses of the pressure, heat-release rate, temperature and emissions are presented. Combustion noise has been shown to decrease significantly when the pilot injected mass increases, while it is scarcely affected by the dwell time between the pilot and main injections. The HC, CO and fuel consumption trends, with respect to both the pilot injection dwell time and mass, are in line with those of conventional combustion systems, and in particular decreasing trends occur as the pilot injection energizing time is increased. Furthermore, a reduced sensitivity of NO_x emissions to both dwell time and pilot injected mass has been found, compared to conventional combustion systems. Finally, it has been observed that soot emissions diminish as the energizing time is shortened, and their dependence on dwell time is influenced to a great extent by the presence of local zones with reduced air-to-fuel ratios within the cylinder. A combined analysis of the results of swirl sweeps and dwell time sweeps is here proposed as a methodology for the detection of any possible interference between pilot combustion burned gases and the main injected fuel. The effect of pilot

Advancing the Limits of Dual Fuel Combustion

Energy Technology Data Exchange (ETDEWEB)

Koenigsson, Fredrik

2012-07-01

There is a growing interest in alternative transport fuels. There are two underlying reasons for this interest; the desire to decrease the environmental impact of transports and the need to compensate for the declining availability of petroleum. In the light of both these factors the Diesel Dual Fuel, DDF, engine is an attractive concept. The primary fuel of the DDF engine is methane, which can be derived both from renewables and from fossil sources. Methane from organic waste; commonly referred to as biomethane, can provide a reduction in greenhouse gases unmatched by any other fuel. The DDF engine is from a combustion point of view a hybrid between the diesel and the otto engine and it shares characteristics with both. This work identifies the main challenges of DDF operation and suggests methods to overcome them. Injector tip temperature and pre-ignitions have been found to limit performance in addition to the restrictions known from literature such as knock and emissions of NO{sub x} and HC. HC emissions are especially challenging at light load where throttling is required to promote flame propagation. For this reason it is desired to increase the lean limit in the light load range in order to reduce pumping losses and increase efficiency. It is shown that the best results in this area are achieved by using early diesel injection to achieve HCCI/RCCI combustion where combustion phasing is controlled by the ratio between diesel and methane. However, even without committing to HCCI/RCCI combustion and the difficult control issues associated with it, substantial gains are accomplished by splitting the diesel injection into two and allocating most of the diesel fuel to the early injection. HCCI/RCCI and PPCI combustion can be used with great effect to reduce the emissions of unburned hydrocarbons at light load. At high load, the challenges that need to be overcome are mostly related to heat. Injector tip temperatures need to be observed since the cooling effect of

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.

Detailed modeling of common rail fuel injection process

NARCIS (Netherlands)

Seykens, X.L.J.; Somers, L.M.T.; Baert, R.S.G.

2005-01-01

Modeling of fuel injection equipment is a tool that is used increasingly for explaining or predicting the effect of advanced diesel injection strategies on combustion and emissions. This paper reports on the modeling of the high-pressure part of a research type Heavy Duty Common Rail (CR) fuel

Combustion of jojoba methyl ester in an indirect injection diesel engine

Energy Technology Data Exchange (ETDEWEB)

Selim, M.Y.E. [United Arab Emirates University, Al-Ain (United Arab Emirates). Mechanical Engineering Dept.; Radwan, M.S.; Elfeky, S.M.S. [Helwan University, Cairo (Egypt). Mechanical Power Engineering Dept.

2003-07-01

An experimental investigation has been carried out to examine for the first time the performance and combustion noise of an indirect injection diesel engine running with new fuel derived from pure jojoba oil, jojoba methyl ester, and its blends with gas oil. A Ricardo E6 compression swirl diesel engine was fully instrumented for the measurement of combustion pressure and its rise rate and other operating parameters. Test parameters included the percentage of jojoba methyl ester in the blend, engine speed, load, injection timing and engine compression ratio. Results showed that the new fuel derived from jojoba is generally comparable and a good replacement to gas oil in diesel engine at most engine operating conditions, in terms of performance parameters and combustion noise produced. (author)

Effect of two-stage injection on combustion and emissions under high EGR rate on a diesel engine by fueling blends of diesel/gasoline, diesel/n-butanol, diesel/gasoline/n-butanol and pure diesel

International Nuclear Information System (INIS)

Zheng, Zunqing; Yue, Lang; Liu, Haifeng; Zhu, Yuxuan; Zhong, Xiaofan; Yao, Mingfa

2015-01-01

Highlights: • Two-stage injection using diesel blended fuel at high EGR (46%) was studied. • Blending fuels induce retarded pilot heat release and have less effect on MPRR. • Effects of injection parameters of blended fuels on emissions are similar to diesel. • Different fuels have little influence on post combustion heat release. • Small quantity post injection close to main results in better efficiency and emissions. - Abstract: The effect of two-stage injection on combustion and emission characteristics under high EGR (46%) condition were experimentally investigated. Four different fuels including pure diesel and blended fuels of diesel/gasoline, diesel/n-butanol, diesel/gasoline/n-butanol were tested. Results show that blending gasoline or/and n-butanol in diesel improves smoke emissions while induces increase in maximum pressure rise rate (MPRR). Adopting pilot injection close to main injection can effectively reduce the peak of premixed heat release rate and MPRR. However, for fuels blends with high percentage of low cetane number fuel, the effect of pilot fuel on ignition can be neglected and the improvement of MPRR is not that obvious. Pilot-main interval presents more obvious effect on smoke than pilot injection rate does, and the smoke emissions decrease with increasing pilot-main interval. A longer main-post interval results in a lower post heat release rate and prolonged combustion duration. While post injection rate has little effect on the start of ignition for post injection. The variation in fuel properties caused by blending gasoline or/and n-butanol into diesel does not impose obvious influence on post combustion. The smoke emission increases first and then declines with retard of post injection timing. Compared to diesel, the smoke emissions of blended fuels are more sensitive to the variation of post injection strategy

From fuel to wheel: how modern fuels behave in combustion engines

Energy Technology Data Exchange (ETDEWEB)

Pischinger, S.; Muether, M.; Fricke, F. [RWTH Aachen (Germany). Inst. for Combustion Engines; Kolbeck, A. [FEV Motorentechnik GmbH und Co KG, Aachen (Germany)

2007-07-01

Fuel consumption/CO{sub 2}-emission reduction for spark-ignited (SI) gasoline engines and pollutant emission reduction for compression-ignited (CI) Diesel engines remain the major challenges for future combustion engine research and development. Currently a variety of technological developments is followed. The fuel has significant influence on the fuel injection and mixing, the self-ignition behaviour and the subsequent combustion process, and hence has considerable impact on the engine conversion efficiency and the emission characteristics. Therefore, a very promising approach to improve the engine efficiency and to lower the pollutant emission is to optimize the fuel composition. Several diesel-like fuels with varying aromatic concentrations (mono-, di-, tri- and total aromatics) and oxygenating components have already shown potential for soot reduction in diesel engines, which is of interest when looking at future biofuel components, which will most likely have particular higher oxygen content. 2nd generation biofuels, e.g. ethanol for SI engines and Fischer-Tropsch diesel for CI engines, have already demonstrated their positive influence on the engine performance, when the combustion system is specifically adapted. The full potential for future high efficient and low emission combustion systems can only be exploited by a simultaneous optimisation of the fuel and the internal combustion engine. (orig.)

Injection and Combustion of RME with Water Emulsions in a Diesel Engine

Directory of Open Access Journals (Sweden)

J. Cisek

2010-01-01

Full Text Available This paper presents ways of using the fully-digitised triggerable AVL VideoScope 513D video system for analysing the injection and combustion inside a diesel engine cylinder fuelled by RME with water emulsions.The research objects were: standard diesel fuel, rapeseed methyl ester (RME and RME – water emulsions. With the aid of a helical flow reactor, stable emulsions with the water fraction up to 30 % weight were obtained, using an additive to prevent the water from separating out of the emulsion.An investigation was made of the effect of the emulsions on exhaust gas emissions (NOX, CO and HC, particulate matter emissions, smoke and the fuel consumption of a one-cylinder HD diesel engine with direct injection. Additionally, the maximum cylinder pressure rise was calculated from the indicator diagram. The test engine was operated at a constant speed of 1 600 rpm and 4 bar BMEP load conditions. The fuel injection and combustion processes were observed and analysed using endoscopes and a digital camera. The temperature distribution in the combustion chamber was analysed quantitatively using the two-colour method. The injection and combustion phenomena were described and compared.A way to reduce NOX formation in the combustion chamber of diesel engines by adding water in the combustion zone was presented. Evaporating water efficiently lowers the peak flame temperature and the temperature in the post-flame zone. For diesel engines, there is an exponential relationship between NOX emissions and peak combustion temperatures. The energy needed to vaporize the water results in lower peak temperatures of the combusted gases, with a consequent reduction in nitrogen oxide formation. The experimental results show up to 50 % NOX emission reduction with the use of 30% water in an RME emulsion, with unchanged engine performance.

Fuel properties to enable lifted-flame combustion

Energy Technology Data Exchange (ETDEWEB)

Kurtz, Eric [Ford Motor Company, Dearborn, MI (United States)

2015-03-15

The Fuel Properties to Enable Lifted-Flame Combustion project responded directly to solicitation DE-FOA-0000239 AOI 1A, Fuels and Lubricants for Advanced Combustion Regimes. This subtopic was intended to encompass clean and highly-efficient, liquid-fueled combustion engines to achieve extremely low engine-out nitrogen oxides (NOx) and particulate matter (PM) as a target and similar efficiency as state-of-the-art direct injection diesel engines. The intent of this project was to identify how fuel properties can be used to achieve controllable Leaner Lifted Flame Combustion (LLFC) with low NOx and PM emissions. Specifically, this project was expected to identify and test key fuel properties to enable LLFC and their compatibility with current fuel systems and to enhance combustion models to capture the effect of fuel properties on advanced combustion. Successful demonstration of LLFC may reduce the need for after treatment devices, thereby reducing costs and improving thermal efficiency. The project team consisted of key technical personnel from Ford Motor Company (FMC), the University of Wisconsin-Madison (UW), Sandia National Laboratories (SNL) and Lawrence Livermore National Laboratories (LLNL). Each partner had key roles in achieving project objectives. FMC investigated fuel properties relating to LLFC and sooting tendency. Together, FMC and UW developed and integrated 3D combustion models to capture fuel property combustion effects. FMC used these modeling results to develop a combustion system and define fuel properties to support a single-cylinder demonstration of fuel-enabled LLFC. UW investigated modeling the flame characteristics and emissions behavior of different fuels, including those with different cetane number and oxygen content. SNL led spray combustion experiments to quantify the effect of key fuel properties on combustion characteristics critical for LLFC, as well as single cylinder optical engine experiments to improve fundamental

Hydrogen fuel injection - the bridge to fuel cells

International Nuclear Information System (INIS)

Gilchrist, J.S.

2004-01-01

'Full text:' For over a century, industry has embraced a wide variety of applications for hydrogen. Since the mid-1970's, the focus of the bulk of hydrogen research has been in the area of fuel cells. Unfortunately, there is limited awareness of more immediate applications for hydrogen as a catalyst designed to improve the performance of existing hydro-carbon fuelled internal combustion engines. Canadian Hydrogen Energy Company manufactures a patented Hydrogen Fuel Injection System (HFI) that produces hydrogen and oxygen from distilled water and injects them, in measured amounts, into the air intake system on any heavy-duty diesel or gasoline application including trucks, buses, stationary generators, etc. In use on over 30 fleets, research is supported by over 40 million miles of field data. The hydrogen acts as a catalyst to promote more complete combustion, with remarkable results. Dramatically reduce emissions, particularly Carbon Monoxide and Particulate Matter. Increase horsepower and torque. Improved fuel efficiency (a minimum 10% improvement is guaranteed). Reduced oil degradation The HFI system offers the first large-scale application of the use of hydrogen and an excellent bridge to the fuel-cell technologies of the future. (author)

Compositional Effects of Gasoline Fuels on Combustion, Performance and Emissions in Engine

KAUST Repository

Ahmed, Ahfaz; Waqas, Muhammad; Naser, Nimal; Singh, Eshan; Roberts, William L.; Chung, Suk-Ho; Sarathy, Mani

2016-01-01

to interpret differences in combustion behavior of gasoline fuels that show similar knock characteristics in a cooperative fuel research (CFR) engine, but may behave differently in direct injection spark ignition (DISI) engines or any other engine combustion

An experimental study of fuel injection strategies in CAI gasoline engine

Energy Technology Data Exchange (ETDEWEB)

Hunicz, J.; Kordos, P. [Department of Combustion Engines and Transport, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin (Poland)

2011-01-15

Combustion of gasoline in a direct injection controlled auto-ignition (CAI) single-cylinder research engine was studied. CAI operation was achieved with the use of the negative valve overlap (NVO) technique and internal exhaust gas re-circulation (EGR). Experiments were performed at single injection and split injection, where some amount of fuel was injected close to top dead centre (TDC) during NVO interval, and the second injection was applied with variable timing. Additionally, combustion at variable fuel-rail pressure was examined. Investigation showed that at fuel injection into recompressed exhaust fuel reforming took place. This process was identified via an analysis of the exhaust-fuel mixture composition after NVO interval. It was found that at single fuel injection in NVO phase, its advance determined the heat release rate and auto-ignition timing, and had a strong influence on NO{sub X} emission. However, a delay of single injection to intake stroke resulted in deterioration of cycle-to-cycle variability. Application of split injection showed benefits of this strategy versus single injection. Examinations of different fuel mass split ratios and variable second injection timing resulted in further optimisation of mixture formation. At equal share of the fuel mass injected in the first injection during NVO and in the second injection at the beginning of compression, the lowest emission level and cyclic variability improvement were observed. (author)

Ultra low injection angle fuel holes in a combustor fuel nozzle

Science.gov (United States)

York, William David

2012-10-23

A fuel nozzle for a combustor includes a mixing passage through which fluid is directed toward a combustion area and a plurality of swirler vanes disposed in the mixing passage. Each swirler vane of the plurality of swirler vanes includes at least one fuel hole through which fuel enters the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes thereby decreasing a flameholding tendency of the fuel nozzle. A method of operating a fuel nozzle for a combustor includes flowing a fluid through a mixing passage past a plurality of swirler vanes and injecting a fuel into the mixing passage in an injection direction substantially parallel to an outer surface of the plurality of swirler vanes.

Sensitivity of dual fuel engine combustion and knocking limits to gaseous fuel composition

Energy Technology Data Exchange (ETDEWEB)

Selim, M.Y.E. [United Arab Emirates University, Al-Ain (United Arab Emirates). Dept. of Mechanical Engineering

2004-02-01

Combustion noise, knock and ignition limits data are measured and presented for a dual fuel engine running on dual fuels of Diesel and three gaseous fuels separately. The gaseous fuels used are liquefied petroleum gas, pure methane and compressed natural gas mixture. The maximum pressure rise rate during combustion is presented as a measure of combustion noise, and the knocking and ignition limits are presented as torque output at the onset of knocking and ignition failure. Experimental investigation on the dual fuel engine revealed the noise generated from combustion, knocking and ignition limits for all gases at different design and operating conditions. A Ricardo E6 Diesel version engine is converted to run on dual fuel of Diesel and the tested gaseous fuel and is used throughout the work. The engine is fully computerized, and the cylinder pressure data, crank angle data and engine operating variables are stored in a PC for off line analysis. The effects of engine speeds, loads, pilot injection angle, pilot fuel quantity and compression ratio on combustion noise, knocking torque, thermal efficiency and maximum pressure are examined for the dual engine running on the three gaseous fuels separately. The combustion noise, knocking and ignition limits are found to relate to the type of gaseous fuels and to the engine design and operating parameters. (author)

Sensitivity of dual fuel engine combustion and knocking limits to gaseous fuel composition

International Nuclear Information System (INIS)

Selim, Mohamed Y.E.

2004-01-01

Combustion noise, knock and ignition limits data are measured and presented for a dual fuel engine running on dual fuels of Diesel and three gaseous fuels separately. The gaseous fuels used are liquefied petroleum gas, pure methane and compressed natural gas mixture. The maximum pressure rise rate during combustion is presented as a measure of combustion noise, and the knocking and ignition limits are presented as torque output at the onset of knocking and ignition failure. Experimental investigation on the dual fuel engine revealed the noise generated from combustion, knocking and ignition limits for all gases at different design and operating conditions. A Ricardo E6 Diesel version engine is converted to run on dual fuel of Diesel and the tested gaseous fuel and is used throughout the work. The engine is fully computerized, and the cylinder pressure data, crank angle data and engine operating variables are stored in a PC for off line analysis. The effects of engine speeds, loads, pilot injection angle, pilot fuel quantity and compression ratio on combustion noise, knocking torque, thermal efficiency and maximum pressure are examined for the dual engine running on the three gaseous fuels separately. The combustion noise, knocking and ignition limits are found to relate to the type of gaseous fuels and to the engine design and operating parameters

Three Dimensional Transient Turbulent Simulations of Scramjet Fuel Injection and Combustion

Science.gov (United States)

Bahbaz, Marwane

2011-11-01

Scramjet is a propulsion system that is more effective for hypersonic flights (M >5). The main objective of the simulation is to understand both the mixing and combustion process of air flow using hydrogen fuel in high speed environment s. The understanding of this phenomenon is used to determine the number of fuel injectors required to increase combustion efficiency and energy transfer. Due to the complexity of this simulation, multiple software tools are used to achieve this objective. First, Solid works is used to draw a scramjet combustor with accurate measurements. Second software tool used is Gambit; It is used to make several types of meshes for the scramjet combustor. Finally, Open Foam and CFD++ are software used to process and post process the scramjet combustor. At this stage, the simulation is divided into two categories. The cold flow category is a series of simulations that include subsonic and supersonic turbulent air flow across the combustor channel with fuel interaction from one or more injectors'. The second category is the combustion simulations which involve fluid flow and fuel mixing with ignition. The simulation and modeling of scramjet combustor will assist to investigate and understand the combustion process and energy transfer in hypersonic environment.

Effect of diesel pre-injection timing on combustion and emission characteristics of compression ignited natural gas engine

International Nuclear Information System (INIS)

Xu, Min; Cheng, Wei; Zhang, Hongfei; An, Tao; Zhang, Shaohua

2016-01-01

Highlights: • Pre-injection timing on combustion and emission of CING engine are studied. • Closely pre-injection operations leads to increase of combustion intensity. • Early pre-injection operations leads to lower combustion intensity. • Early pre-injection modes provide better NO x emission. - Abstract: Pre-injection strategy is considered to be one of the most important ways to improve diesel engine performance, emission and combustion. It is the same important factor in pilot diesel compression ignition natural gas (CING) engine. In this study, effects of pre-injection timing on combustion and emission performances were experimentally studied in a CING engine which was modified from a turbocharged six-cylinder diesel engine. The experiments were conducted at constant speed of 1400 rpm and different engine loads with a constant fuel injection pressure of 1100 bar. Main injection timing was fixed at 10 °CA BTDC in the advance process of pre-injection timing. The cylinder pressure, heart release rate (HRR), pressure rise rate (PRR), start of combustion (SOC) and coefficient of variation (COV IMEP ), as well as NO x , HC and CO emissions were analyzed. The results indicated that closely pre-injection operations lead to the advance of SOC which intensified combustion of in-cylinder mixture, thereby resulting in higher cylinder pressure, HRR and PRR, as well higher NO x emissions and lower HC and CO emissions. However, early pre-injection operations lead to lower cylinder pressure, HRR and PRR due to decreasing in combustion intensity. Pre-injection timing of 70 °CA BTDC is a conversion point in which influence of pre-injection fuel on ignition and combustion of natural gas nearly disappeared and lowest NO x emission could be obtained. Compared with single injection ignition mode, NO x emissions at the conversion point were reduced by 33%, 38% and 7% at engine load of 38%, 60% and 80% respectively. This is important for the conditions that ignition fuel

Apparatus and method for controlling the secondary injection of fuel

Science.gov (United States)

Martin, Scott M.; Cai, Weidong; Harris, Jr., Arthur J.

2013-03-05

A combustor (28) for a gas turbine engine is provided comprising a primary combustion chamber (30) for combusting a first fuel to form a combustion flow stream (50) and a transition piece (32) located downstream from the primary combustion chamber (30). The transition piece (32) comprises a plurality of injectors (66) located around a circumference of the transition piece (32) for injecting a second fuel into the combustion flow stream (50). The injectors (66) are effective to create a radial temperature profile (74) at an exit (58) of the transition piece (32) having a reduced coefficient of variation relative to a radial temperature profile (64) at an inlet (54) of the transition piece (32). Methods for controlling the temperature profile of a secondary injection are also provided.

Quantitative Imaging of Turbulent Mixing Dynamics in High-Pressure Fuel Injection to Enable Predictive Simulations of Engine Combustion

Energy Technology Data Exchange (ETDEWEB)

Frank, Jonathan H. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Reacting Flows Dept.; Pickett, Lyle M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engine Combustion Dept.; Bisson, Scott E. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Remote Sensing and Energetic Materials Dept.; Patterson, Brian D. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). combustion Chemistry Dept.; Ruggles, Adam J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Reacting Flows Dept.; Skeen, Scott A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engine Combustion Dept.; Manin, Julien Luc [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engine Combustion Dept.; Huang, Erxiong [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Reacting Flows Dept.; Cicone, Dave J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engine Combustion Dept.; Sphicas, Panos [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Engine Combustion Dept.

2015-09-01

In this LDRD project, we developed a capability for quantitative high - speed imaging measurements of high - pressure fuel injection dynamics to advance understanding of turbulent mixing in transcritical flows, ignition, and flame stabilization mechanisms, and to provide e ssential validation data for developing predictive tools for engine combustion simulations. Advanced, fuel - efficient engine technologies rely on fuel injection into a high - pressure, high - temperature environment for mixture preparation and com bustion. Howe ver, the dynamics of fuel injection are not well understood and pose significant experimental and modeling challenges. To address the need for quantitative high - speed measurements, we developed a Nd:YAG laser that provides a 5ms burst of pulses at 100 kHz o n a robust mobile platform . Using this laser, we demonstrated s patially and temporally resolved Rayleigh scattering imaging and particle image velocimetry measurements of turbulent mixing in high - pressure gas - phase flows and vaporizing sprays . Quantitativ e interpretation of high - pressure measurements was advanced by reducing and correcting interferences and imaging artifacts.

New concept of combustion technology in small DI diesel engines. 4th Report. Effects of fuel injection rates on MK combustion; Kogata chokufun diesel kikan no shinnensho concept. 4. Funsharitsu no MK nensho eno eikyo

Energy Technology Data Exchange (ETDEWEB)

Kimura, S; Matsui, Y; Kamihara, T [Nissan Motor Co. Ltd., Tokyo (Japan)

1997-10-01

A previous paper showed that EGR cooling and a low compression ratio which prolongs the ignition delay can expand the area of the new combustion concept. Experimental investigations were conducted in this research to examine the effects of the fuel injection rates, the injection pressure and the injection duration, on the exhaust emissions of an engine incorporating the MK concept The results showed that a higher injection pressure was effective in reducing NOx and particulate matter (PM) under MK combustion conditions. 10 refs., 9 figs., 1 tab.

The role of the fuel injection system for combustion process optimization of highly turbocharged PC diesel engines; Die Rolle des Einspritzsystems bei der Brennverfahrensoptimierung von hochaufgeladenen Pkw-Dieselmotoren

Energy Technology Data Exchange (ETDEWEB)

Gerhardt, Juergen; Leonhard, Rolf; Krueger, Michael; Naber, Dirk; Pitt, J. [Robert Bosch GmbH, Stuttgart (Germany)

2008-07-01

In order to comply with continuously rising requirements from emission legislation and fuel economy enhancement, modern Diesel engines for passenger cars still offer a variety of measures. Focus of this paper is the importance of a highly flexible fuel-injection system and an optimized injection strategy as direct measures to improve both, tail-pipe emission as well as vehicle fuel economy. An integrated system approach of high pressure pump, injector and nozzle provides the latest injection patterns combined with an increased rail pressure level with a best-in-class hydraulic efficiency. The resulting improvement in the injection system and thus in the combustion also enables the introduction of additional indirect, very effective measures for fuel consumption reduction, such as downsizing and downspeeding. In order to fully utilize the potent of the mentioned approaches, the application of advanced boosting technology is an additional key factor. Bosch Diesel injection technology and optimized combustion systems pave the way to achieve the goal of efficient emission reduction. (orig.)

Advanced diesel electronic fuel injection and turbocharging

Science.gov (United States)

Beck, N. J.; Barkhimer, R. L.; Steinmeyer, D. C.; Kelly, J. E.

1993-12-01

The program investigated advanced diesel air charging and fuel injection systems to improve specific power, fuel economy, noise, exhaust emissions, and cold startability. The techniques explored included variable fuel injection rate shaping, variable injection timing, full-authority electronic engine control, turbo-compound cooling, regenerative air circulation as a cold start aid, and variable geometry turbocharging. A Servojet electronic fuel injection system was designed and manufactured for the Cummins VTA-903 engine. A special Servojet twin turbocharger exhaust system was also installed. A series of high speed combustion flame photos was taken using the single cylinder optical engine at Michigan Technological University. Various fuel injection rate shapes and nozzle configurations were evaluated. Single-cylinder bench tests were performed to evaluate regenerative inlet air heating techniques as an aid to cold starting. An exhaust-driven axial cooling air fan was manufactured and tested on the VTA-903 engine.

Combustion of alternative fuels in vortex trapped combustor

International Nuclear Information System (INIS)

Ghenai, Chaouki; Zbeeb, Khaled; Janajreh, Isam

2013-01-01

Highlights: ► We model the combustion of alternative fuels in trapped vortex combustor (TVC). ► We test syngas and hydrogen/hydrocarbon mixture fuels. ► We examine the change in combustion performance and emissions of TVC combustor. ► Increasing the hydrogen content of the fuel will increase the temperature and NO x emissions. ► A high combustor efficiency is obtained for fuels with different compositions and LHV. - Abstract: Trapped vortex combustor represents an efficient and compact combustor for flame stability. Combustion stability is achieved through the use of cavities in which recirculation zones of hot products generated by the direct injection of fuel and air are created and acting as a continuous source of ignition for the incoming main fuel–air stream. Computational Fluid Dynamics analysis was performed in this study to test the combustion performance and emissions from the vortex trapped combustor when natural gas fuel (methane) is replaced with renewable and alternative fuels such as hydrogen and synthetic gas (syngas). The flame temperature, the flow field, and species concentrations inside the Vortex Trapped Combustor were obtained. The results show that hydrogen enriched hydrocarbon fuels combustion will result in more energy, higher temperature (14% increase when methane is replaced with hydrogen fuels) and NO x emissions, and lower CO 2 emissions (50% decrease when methane is replaced with methane/hydrogen mixture with 75% hydrogen fraction). The NO x emission increases when the fraction of hydrogen increases for methane/hydrogen fuel mixture. The results also show that the flame for methane combustion fuel is located in the primary vortex region but it is shifted to the secondary vortex region for hydrogen combustion.

Influence of fuel injection pressures on Calophyllum inophyllum methyl ester fuelled direct injection diesel engine

International Nuclear Information System (INIS)

Nanthagopal, K.; Ashok, B.; Karuppa Raj, R. Thundil

2016-01-01

Highlights: • Effect of injection pressure of Calophyllum inophyllum biodiesel is investigated. • Engine characteristics of 100% Calophyllum inophyllum biodiesel has been performed. • Calophyllum inophyllum is a non-edible source for biodiesel production. • Increase in injection pressure of biodiesel, improves the fuel economy. • Incylinder pressure characteristics of biodiesel follows similar trend as of diesel. - Abstract: The trend of using biodiesels in compression ignition engines have been the focus in recent decades due to the promising environmental factors and depletion of fossil fuel reserves. This work presents the effect of Calophyllum inophyllum methyl ester on diesel engine performance, emission and combustion characteristics at different injection pressures. Experimental investigations with varying injection pressures of 200 bar, 220 bar and 240 bar have been carried out to analyse the parameters like brake thermal efficiency, specific fuel consumption, heat release rate and engine emissions of direct injection diesel engine fuelled with 100% biodiesel and compared with neat diesel. The experimental results revealed that brake specific fuel consumption of C. inophyllum methyl ester fuelled engine has been reduced to a great extent with higher injection pressure. Significant reduction in emissions of unburnt hydrocarbons, carbon monoxide and smoke opacity have been observed during fuel injection of biodiesel at 220 bar compared to other fuel injection pressures. However oxides of nitrogen increased with increase in injection pressures of C. inophyllum methyl ester and are always higher than that of neat diesel. In addition the combustion characteristics of biodiesel at all injection pressures followed a similar trend to that of conventional diesel.

Investigation of the effect of heated ethanol fuel on combustion and emissions of an ethanol direct injection plus gasoline port injection (EDI + GPI) engine

International Nuclear Information System (INIS)

Huang, Yuhan; Hong, Guang

2016-01-01

Highlights: • Effect of EDI heating on the EDI + GPI engine performance was investigated. • CO and HC were significantly reduced and NO was slightly increased by EDI heating. • IMEP and combustion speed were slightly reduced by EDI heating. • EDI heating is effective to address the evaporation and over-cooling issues of EDI + GPI engine. - Abstract: Ethanol direct injection plus gasoline port injection (EDI + GPI) is a new technology to utilise ethanol fuel more efficiently and flexibly in spark ignition engines. One issue needs to be addressed in the development of EDI + GPI is the ethanol fuel’s low vapour pressure and large latent heat which slow down the ethanol’s evaporation and result in the mixture unready for combustion by the time of spark ignition and the consequent increase of CO and HC emissions. Heating the ethanol fuel to be directly injected (EDI heating) has been proposed to address this issue. This paper reports the investigation of the effect of EDI heating on the combustion and emissions of a research engine equipped with EDI + GPI. The results showed that EDI heating effectively reduced the CO and HC emissions of the engine due to the increase of evaporation rate and reduced fuel impingement and local over-cooling. The reduction of CO and HC became more significant with the increase of ethanol ratio. When the temperature of the ethanol fuel was increased by 40 °C, the CO and HC were reduced by as much as 43% and 51% respectively in EDI only condition at the original spark timing of 15 CAD BTDC, and 15% and 47% respectively at the minimum spark advance for best torque (MBT) timing of 19 CAD BTDC. On the other hand, the NO emission was slightly increased, but still much smaller than that in GPI only condition due to the strong cooling effect and low combustion temperature of EDI. The IMEP and combustion speed were slightly reduced by EDI heating due to the decrease of injector fuel flow rate and spray collapse of flash-boiling. The

Toyota's innovative concept for a SI direct fuel injection system

Energy Technology Data Exchange (ETDEWEB)

Matsumura, E.; Kanda, M.; Hattori, F. [Toyota Motor Corporation, Shizuoka (Japan)

2013-08-01

To reduce environmental footprint of vehicle, demands have been intensifying for gasoline engines with lower fuel consumption, improved power performance, and lower emissions. The adoption of direct injection technology is rapidly expanding because it is an efficient way to achieve these targets. Originally, gasoline direct injection engines were designed to allow stratified lean combustion, which has a significant fuel consumption reduction effect. However, as exhaust gas emission regulations have become more stringent, the combustion strategy of most gasoline direct injection engines was changed to homogeneous stoichiometric combustion. Stratified lean combustion can nevertheless be used during catalyst heat up phase to fasten it and reduce pollutant emissions. In addition, exhaust gas recirculation (EGR), widely used in Diesel combustion, can also be used in gasoline engine to further reduce fuel consumption by reducing fuel requirement to maintain stoichiometric combustion. Regulations covering the emission of particulate matter (PM), which is an issue of direct injection, have also been strengthened, such as by the introduction of particle number restrictions in Europe. Based on this background, this article introduces the new Toyota direct injection (D-4S) concept that was developed to respond to such requirements. In this concept, combustion speed and air-fuel mixture homogeneity were improved by active usage of spray jets to strengthen the in-cylinder flow. The PM number and oil dilution were significantly reduced by usage of a thin fan-shaped spray formed by a slit nozzle. In addition, this developed slit nozzle has high potential to avoid deposit build-up. Moreover, fast catalyst warming up performance was secured to achieve a low level of emissions compatible with the super ultra low emission vehicle (SULEV) standards in North America. (orig.)

Effects of Injection Timing on Fluid Flow Characteristics of Partially Premixed Combustion Based on High-Speed Particle Image Velocimetry

KAUST Repository

Izadi Najafabadi, Mohammad

2017-03-28

Partially Premixed Combustion (PPC) is a promising combustion concept ,based on judicious tuning of the charge stratification, to meet the increasing demands of emission legislation and to improve fuel efficiency. Longer ignition delays of PPC in comparison with conventional diesel combustion provide better fuel/air mixture which decreases soot and NO emissions. Moreover, a proper injection timing and strategy for PPC can improve the combustion stability as a result of a higher level of fuel stratification in comparison with the Homogeneous Charge Compression Ignition (HCCI) concept. Injection timing is the major parameter with which to affect the level of fuel and combustion stratification and to control the combustion phasing and the heat release behavior. The scope of the present study is to investigate the fluid flow characteristics of PPC at different injection timings. To this end, high-speed Particle Image Velocimetry (PIV) is implemented in a light-duty optical engine to measure fluid flow characteristics, including the flow fields, mean velocity and cycle-resolved turbulence, inside the piston bowl as well as the squish region with a temporal resolution of 1 crank angle degree at 800 rpm. Two injectors, having 5 and 7 holes, were compared to see their effects on fluid flow and heat release behavior for different injection timings. Reactive and non-reactive measurements were performed to distinguish injection-driven and combustion-driven turbulence. Formation of vortices and higher turbulence levels enhance the air/fuel interaction, changing the level of fuel stratification and combustion duration. Results demonstrate clearly how turbulence level correlates with heat release behavior, and provide a quantitative dataset for validation of numerical simulations.

Premixed direct injection nozzle for highly reactive fuels

Science.gov (United States)

Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin Paul; York, William David; Uhm, Jong Ho; Zuo, Baifang

2013-09-24

A fuel/air mixing tube for use in a fuel/air mixing tube bundle is provided. The fuel/air mixing tube includes an outer tube wall extending axially along a tube axis between an inlet end and an exit end, the outer tube wall having a thickness extending between an inner tube surface having a inner diameter and an outer tube surface having an outer tube diameter. The tube further includes at least one fuel injection hole having a fuel injection hole diameter extending through the outer tube wall, the fuel injection hole having an injection angle relative to the tube axis. The invention provides good fuel air mixing with low combustion generated NOx and low flow pressure loss translating to a high gas turbine efficiency, that is durable, and resistant to flame holding and flash back.

Effects of turbulence enhancement on combustion process using a double injection strategy in direct-injection spark-ignition (DISI) gasoline engines

International Nuclear Information System (INIS)

Kim, Taehoon; Song, Jingeun; Park, Sungwook

2015-01-01

Highlights: • Using double injection strategy, turbulent kinetic energy can be improved with slight decrease in mixture homogeneity. • Retarded first injection timing reduces vapor fuel loss to intake port. • Double injection increases tumble intensity. • High turbulent intensity caused by double injection increases flame propagation speed. - Abstract: Direct-injection spark-ignition (DISI) gasoline engines have been spotlighted due to their high thermal efficiency. Increase in the compression ratio that result from the heat absorption effect of fuel vaporization induces higher thermal efficiency than found in port fuel injection (PFI) engines. Since fuel is injected at the cylinder directly, various fuel injection strategies can be used. In this study, turbulent intensity was improved by a double injection strategy while maintaining mixture homogeneity. To analyze the turbulence enhancement effects using the double injection strategy, a side fuel injected, homogeneous-charge-type DISI gasoline engine with a multi-hole-type injector was utilized. The spray model was evaluated using experimental data for various injection pressures and the combustion model was evaluated for varied ignition timing. First and second injection timing was swept by 20 degree interval. The turbulent kinetic energy and mixture inhomogeneity index were mapped. First injection at the middle of the intake stroke and second injection early in the compression stroke showed improved turbulent characteristics that did not significantly decrease with mixture homogeneity. A double injection case that showed improved turbulent intensity while maintaining an adequate level of mixture homogeneity and another double injection case that showed significantly improved turbulent intensity with a remarkable decrease in mixture homogeneity were considered for combustion simulation. We found that the improved turbulent intensity increased the flame propagation speed. Also, the mixture homogeneity

Ethanol-fueled low temperature combustion: A pathway to clean and efficient diesel engine cycles

International Nuclear Information System (INIS)

Asad, Usman; Kumar, Raj; Zheng, Ming; Tjong, Jimi

2015-01-01

Highlights: • Concept of ethanol–diesel fueled Premixed Pilot Assisted Combustion (PPAC). • Ultra-low NOx and soot with diesel-like thermal efficiency across the load range. • Close to TDC pilot injection timing for direct combustion phasing control. • Minimum pilot quantity (15% of total energy input) for clean, stable operation. • Defined heat release profile distribution (HRPD) to optimize pilot-ethanol ratio. - Abstract: Low temperature combustion (LTC) in diesel engines offers the benefits of ultra-low NOx and smoke emissions but suffers from lowered energy efficiency due to the high reactivity and low volatility of diesel fuel. Ethanol from renewable biomass provides a viable alternate to the petroleum based transportation fuels. The high resistance to auto-ignition (low reactivity) and its high volatility make ethanol a suitable fuel for low temperature combustion (LTC) in compression-ignition engines. In this work, a Premixed Pilot Assisted Combustion (PPAC) strategy comprising of the port fuel injection of ethanol, ignited with a single diesel pilot injection near the top dead centre has been investigated on a single-cylinder high compression ratio diesel engine. The impact of the diesel pilot injection timing, ethanol to diesel quantity ratio and exhaust gas recirculation on the emissions and efficiency are studied at 10 bar IMEP. With the lessons learnt, successful ethanol–diesel PPAC has been demonstrated up to a load of 18 bar IMEP with ultra-low NOx and soot emissions across the full load range. The main challenge of PPAC is the reduced combustion efficiency especially at low loads; therefore, the authors have presented a combustion control strategy to allow high efficiency, clean combustion across the load range. This work entails to provide a detailed framework for the ethanol-fueled PPAC to be successfully implemented.

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)

Combustion performance, flame, and soot characteristics of gasoline–diesel pre-blended fuel in an optical compression-ignition engine

International Nuclear Information System (INIS)

Jeon, Joonho; Lee, Jong Tae; Kwon, Sang Il; Park, Sungwook

2016-01-01

Highlights: • Gasoline–diesel pre-blended fuel was investigated in an optical direct-injection diesel engine. • KIVA3V-CHEMKIN code modeled blended fuel spray and combustion with discrete multi-component model. • Flame and soot characteristics in the combustion chamber were shown by optical kits. • Combustion performance and soot emissions for gasoline–diesel blended fuel were discussed. - Abstract: Among the new combustion technologies available for internal combustion engines to enhance performance and reduce exhausted emissions, the homogeneous charge compression ignition method is one of the most effective strategies for the compression-ignition engine. There are some challenges to realize the homogeneous charge compression ignition method in the compression-ignition engine. The use of gasoline–diesel blended fuel has been suggested as an alternative strategy to take advantages of homogeneous charge compression ignition while overcoming its challenges. Gasoline and diesel fuels are reference fuels for the spark-ignition and compression-ignition engines, respectively, both of which are widely used. The application of both these fuels together in the compression-ignition engine has been investigated using a hybrid injection system combining port fuel injection (gasoline) and direct injection (diesel); this strategy is termed reactivity controlled compression ignition. However, the pre-blending of gasoline and diesel fuels for direct injection systems has been rarely studied. For the case of direct injection of pre-blended fuel into the cylinder, various aspects of blended fuels should be investigated, including their spray breakup, fuel/air mixing, combustion development, and emissions. In the present study, the use of gasoline–diesel pre-blended fuel in an optical single-cylinder compression-ignition engine was investigated under various conditions of injection timing and pressure. Furthermore, KIVA-3V release 2 code was employed to model the

Fuel Vaporization and Its Effect on Combustion in a High-Speed Compression-Ignition Engine

Science.gov (United States)

Rothrock, A M; Waldron, C D

1933-01-01

The tests discussed in this report were conducted to determine whether or not there is appreciable vaporization of the fuel injected into a high-speed compression-ignition engine during the time available for injection and combustion. The effects of injection advance angle and fuel boiling temperature were investigated. The results show that an appreciable amount of the fuel is vaporized during injection even though the temperature and pressure conditions in the engine are not sufficient to cause ignition either during or after injection, and that when the conditions are such as to cause ignition the vaporization process affects the combustion. The results are compared with those of several other investigators in the same field.

Modulated diesel fuel injection strategy for efficient-clean utilization of low-grade biogas

International Nuclear Information System (INIS)

Wang, Xiaole; Qian, Yong; Zhou, Qiyan; Lu, Xingcai

2016-01-01

Highlights: • Influences of direct injection strategy on biogas RCCI mode are researched. • Excessive early pilot injection timing leads to the retard of combustion. • Overall indicated thermal efficiency of low-grade biogas can be higher than 40%. • Pilot injection timing has strong influence on particle size distribution. • Composition of biogas has a great influence on the gas emissions. - Abstract: Recently, as a kind of renewable fuel, low-grade biogas has been researched to apply in internal combustion engine. In this paper, an experimental study was conducted to study the influence of injection strategies on the efficient utilization of low-grade biogas in Reactivity Controlled Compression Ignition (RCCI) mode with port fuel injection of biogas and in-cylinder direct injection of diesel based on a modified electronic controlled high-pressure directly injected compression ignition engine. Considered the high proportion of inert gas in biogas, a four-components simulated gas (H_2:CO:CH_4:N_2 = 5:40:5:50 vol%) has been selected as test fuels to simulate biogas. The effects of several injection control parameters such as pilot injection timing, main injection timing, common rail pressure and pilot injection ratio on the combustion and emissions are analyzed in detail. The research demonstrates that the main injection timing can effectively control the combustion phase and excessive early pilot injection timing leads to retard of combustion. CO emissions are relatively high due to homogenous charge of biogas. NOx and smoke emissions can be effectively controlled. In RCCI mode, the indicated thermal efficiency of biogas/diesel can reach 40%.

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).

Experimental analysis of ethanol dual-fuel combustion in a heavy-duty diesel engine: An optimisation at low load

International Nuclear Information System (INIS)

Pedrozo, Vinícius B.; May, Ian; Dalla Nora, Macklini; Cairns, Alasdair; Zhao, Hua

2016-01-01

Highlights: • Dual-fuel combustion offers promising results on a stock heavy-duty diesel engine. • The use of split diesel injections extends the benefits of the dual-fuel mode. • Ethanol–diesel dual-fuel combustion results in high indicated efficiencies. • NOx and soot emissions are significantly reduced. • Combustion efficiency reaches 98% with an ethanol energy ratio of 53%. - Abstract: Conventional diesel combustion produces harmful exhaust emissions which adversely affect the air quality if not controlled by in-cylinder measures and exhaust aftertreatment systems. Dual-fuel combustion can potentially reduce the formation of nitrogen oxides (NOx) and soot which are characteristic of diesel diffusion flame. The in-cylinder blending of different fuels to control the charge reactivity allows for lower local equivalence ratios and temperatures. The use of ethanol, an oxygenated biofuel with high knock resistance and high latent heat of vaporisation, increases the reactivity gradient. In addition, renewable biofuels can provide a sustainable alternative to petroleum-based fuels as well as reduce greenhouse gas emissions. However, ethanol–diesel dual-fuel combustion suffers from poor engine efficiency at low load due to incomplete combustion. Therefore, experimental studies were carried out at 1200 rpm and 0.615 MPa indicated mean effective pressure on a heavy-duty diesel engine. Fuel delivery was in the form of port fuel injection of ethanol and common rail direct injection of diesel. The objective was to improve combustion efficiency, maximise ethanol substitution, and minimise NOx and soot emissions. Ethanol energy fractions up to 69% were explored in conjunction with the effect of different diesel injection strategies on combustion, emissions, and efficiency. Optimisation tests were performed for the optimum fuelling and diesel injection strategy. The resulting effects of exhaust gas recirculation, intake air pressure, and rail pressure were

Combustion modelling of a fuel oil flame; Modelisation de la combustion d`une flamme de fuel

Energy Technology Data Exchange (ETDEWEB)

Flour, I.; Mechitouan, N.

1996-10-01

The combustion modelling of a fuel oil flame has been realised in the scope of the R and D `Combustion Turbines`. This report presents the results of the 2D simulation of a fuel oil flame (n-octane), at atmospherical pressure, without swirl, realised using the Eulerian two-phase flow software Melodif. This calculation has been defined in collaboration with IFP, using experimental data from the IFRP. The hollow cone spray of liquid fuel is injected in the middle of the combustion chamber, with a co-flowing annular air. The furnace diameter is 2 meter and its length is 6,25 meter. A large recirculation zone is induced by the air flow, and leads to take into account the whole furnace, in order to avoid some problems with the limit conditions at the outlet. This calculation deals with droplets evaporation, gaseous phase combustion and radiation heat transfer. Predictions concerning gaseous axial mean velocity and mean temperature gradient in the flame, are in good agreement with measurements. However the temperature is too low in the peripheral zone of the flow. This is probably due to the fact that heat exchanges at the wall furnace are not correctly represented, because of a lack of detailed limit conditions for the walls. The mean radial velocity is not so well predicted, but this measurement is also quite difficult in a strongly longitudinal flow. The results concerning the dispersed phase will not be compared, because no measurements on the liquid fuel were available. As it has been experimentally observed, the simulation shows that the fuel oil spray quickly evaporates as it enters the combustion chamber. This result allows to propose to use an homogeneous approach (hypothesis of no-slipping between the two phases) in an Eulerian one-phase flow code, in case of a 3D simulation of liquid fuel turbine. (authors)

Characteristics of pressure wave in common rail fuel injection system of high-speed direct injection diesel engines

Directory of Open Access Journals (Sweden)

Mohammad Reza Herfatmanesh

2016-05-01

Full Text Available The latest generation of high-pressure common rail equipment now provides diesel engines possibility to apply as many as eight separate injection pulses within the engine cycle for reducing emissions and for smoothing combustion. With these complicated injection arrangements, optimizations of operating parameters for various driving conditions are considerably difficult, particularly when integrating fuel injection parameters with other operating parameters such as exhaust gas recirculation rate and boost pressure together for evaluating calibration results. Understanding the detailed effects of fuel injection parameters upon combustion characteristics and emission formation is therefore particularly critical. In this article, the results and discussion of experimental investigations on a high-speed direct injection light-duty diesel engine test bed are presented for evaluating and analyzing the effects of main adjustable parameters of the fuel injection system on all regulated emission gases and torque performance. Main injection timing, rail pressure, pilot amount, and particularly pilot timing have been examined. The results show that optimization of each of those adjustable parameters is beneficial for emission reduction and torque improvement under different operating conditions. By exploring the variation in the interval between the pilot injection and the main injection, it is found that the pressure wave in the common rail has a significant influence on the subsequent injection. This suggests that special attentions must be paid for adjusting pilot timing or any injection interval when multi-injection is used. With analyzing the fuel amount oscillation of the subsequent injections to pilot separation, it demonstrates that the frequency of regular oscillations of the actual fuel amount or the injection pulse width with the variation in pilot separation is always the same for a specified fuel injection system, regardless of engine speed

A numerical study of the effects of injection rate shape on combustion and emission of diesel engines

Directory of Open Access Journals (Sweden)

He Zhixia

2014-01-01

Full Text Available The spray characteristics including spray droplet sizes, droplet distribution, spray tip penetration length and spray diffusion angle directly affects the mixture process of fuel and oxygen and then plays an important role for the improvement of combustion and emission performance of diesel engines. Different injection rate shapes may induce different spray characteristics and then further affect the subsequent combustion and emission performance of diesel engines. In this paper, the spray and combustion processes based on four different injection rate shapes with constant injection duration and injected fuel mass were simulated in the software of AVL FIRE. The numerical models were validated through comparing the results from the simulation with those from experiment. It was found that the dynamic of diesel engines with the new proposed hump shape of injection rate and the original saddle shape is better than that with the injection rate of rectangle and triangle shape, but the emission of NOX is higher. And the soot emission is lowest during the late injection period for the new hump-shape injection rate because of a higher oxidation rate with a better mixture between fuel and air under the high injection pressure.

An Assessment of Combustion Dynamics in a Low-Nox, Second-Generation Swirl-Venturi Lean Direct Injection Combustion Concept

Science.gov (United States)

Tacina, K. M.; Chang, C. T.; Lee, P.; Mongia, H.; Podboy, D. P.; Dam, B.

2015-01-01

Dynamic pressure measurements were taken during flame-tube emissions testing of three second-generation swirl-venturi lean direct injection (SV-LDI) combustor configurations. These measurements show that combustion dynamics were typically small. However, a small number of points showed high combustion dynamics, with peak-to-peak dynamic pressure fluctuations above 0.5 psi. High combustion dynamics occurred at low inlet temperatures in all three SV-LDI configurations, so combustion dynamics were explored further at low temperature conditions. A point with greater than 1.5 psi peak-to-peak dynamic pressure fluctuations was identified at an inlet temperature of 450!F, a pressure of 100 psia, an air pressure drop of 3%, and an overall equivalence ratio of 0.35. This is an off design condition: the temperature and pressure are typical of 7% power conditions, but the equivalence ratio is high. At this condition, the combustion dynamics depended strongly on the fuel staging. Combustion dynamics could be reduced significantly without changing the overall equivalence ratio by shifting the fuel distribution between stages. Shifting the fuel distribution also decreased NOx emissions.

Influence of engine speed and the course of the fuel injection characteristics on forming the average combustion temperature in the cylinder of turbo diesel engine

Directory of Open Access Journals (Sweden)

Piotr GUSTOF

2007-01-01

Full Text Available Average combustion temperatures inside a turbo diesel engine for the same load and the same total doze of fuel for two rotational speeds: 2004 [rpm] and 4250 [rpm] are presented in this paper. The aim of this work is also the evaluation of the influence of the temporary course of the fuel injection characteristics on forming temperature in theengine cylinder space for these temperatures. The calculations were carried out by means of two zone combustion model.

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.

Compositional Effects of Gasoline Fuels on Combustion, Performance and Emissions in Engine

KAUST Repository

Ahmed, Ahfaz

2016-10-17

Commercial gasoline fuels are complex mixtures of numerous hydrocarbons. Their composition differs significantly owing to several factors, source of crude oil being one of them. Because of such inconsistency in composition, there are multiple gasoline fuel compositions with similar octane ratings. It is of interest to comparatively study such fuels with similar octane ratings and different composition, and thus dissimilar physical and chemical properties. Such an investigation is required to interpret differences in combustion behavior of gasoline fuels that show similar knock characteristics in a cooperative fuel research (CFR) engine, but may behave differently in direct injection spark ignition (DISI) engines or any other engine combustion modes. Two FACE (Fuels for Advanced Combustion Engines) gasolines, FACE F and FACE G with similar Research and Motor Octane Numbers but dissimilar physical properties were studied in a DISI engine under two sets of experimental conditions; the first set involved early fuel injection to allow sufficient time for fuel-air mixing hence permitting operation similar to homogenous DISI engines, while the second set consists of advance of spark timings to attain MBT (maximum brake torque) settings. These experimental conditions are repeated across different load points to observe the effect of increasing temperature and pressure on combustion and emission parameters. The differences in various engine-out parameters are discussed and interpreted in terms of physical and thermodynamic properties of the fuels.

Air fuel ratio detector corrector for combustion engines using adaptive neurofuzzy networks

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Nidhi Arora

2013-07-01

Full Text Available A perfect mix of the air and fuel in internal combustion engines is desirable for proper combustion of fuel with air. The vehicles running on road emit harmful gases due to improper combustion. This problem is severe in heavy vehicles like locomotive engines. To overcome this problem, generally an operator opens or closes the valve of fuel injection pump of locomotive engines to control amount of air going inside the combustion chamber, which requires constant monitoring. A model is proposed in this paper to alleviate combustion process. The method involves recording the time-varying flow of fuel components in combustion chamber. A Fuzzy Neural Network is trained for around 40 fuels to ascertain the required amount of air to form a standard mix to produce non-harmful gases and about 12 fuels are used for testing the network’s performance. The network then adaptively determines the additional/subtractive amount of air required for proper combustion. Mean square error calculation ensures the effectiveness of the network’s performance.

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.

Impact of physical properties of mixture of diesel and biodiesel fuels on hydrodynamic characteristics of fuel injection system

Directory of Open Access Journals (Sweden)

Filipović Ivan M.

2014-01-01

Full Text Available One of the alternative fuels, originating from renewable sources, is biodiesel fuel, which is introduced in diesel engines without major construction modifications on the engine. Biodiesel fuel, by its physical and chemical properties, is different from diesel fuel. Therefore, it is expected that by the application of a biodiesel fuel, the characteristic parameters of the injection system will change. These parameters have a direct impact on the process of fuel dispersion into the engine cylinder, and mixing with the air, which results in an impact on the quality of the combustion process. Method of preparation of the air-fuel mixture and the quality of the combustion process directly affect the efficiency of the engine and the level of pollutant emissions in the exhaust gas, which today is the most important criterion for assessing the quality of the engine. The paper presents a detailed analysis of the influence of physical properties of a mixture of diesel and biodiesel fuels on the output characteristics of the fuel injection system. The following parameters are shown: injection pressure, injection rate, the beginning and duration of injection, transformation of potential into kinetic energy of fuel and increase of energy losses in fuel injection system of various mixtures of diesel and biodiesel fuels. For the analysis of the results a self-developed computer program was used to simulate the injection process in the system. Computational results are verified using the experiment, for a few mixtures of diesel and biodiesel fuels. This paper presents the verification results for diesel fuel and biodiesel fuel in particular.

Oxy-fuel combustion of solid fuels

DEFF Research Database (Denmark)

Toftegaard, Maja Bøg; Brix, Jacob; Jensen, Peter Arendt

2010-01-01

Oxy-fuel combustion is suggested as one of the possible, promising technologies for capturing CO2 from power plants. The concept of oxy-fuel combustion is removal of nitrogen from the oxidizer to carry out the combustion process in oxygen and, in most concepts, recycled flue gas to lower the flame...... provide additional options for improvement of process economics are however likewise investigated. Of particular interest is the change of the combustion process induced by the exchange of carbon dioxide and water vapor for nitrogen as diluent. This paper reviews the published knowledge on the oxy......-fuel process and focuses particularly on the combustion fundamentals, i.e. flame temperatures and heat transfer, ignition and burnout, emissions, and fly ash characteristics. Knowledge is currently available regarding both an entire oxy-fuel power plant and the combustion fundamentals. However, several...

Advanced Optical Diagnostic Methods for Describing Fuel Injection and Combustion Flowfield Phenomena

Science.gov (United States)

Locke, Randy J.; Hicks, Yolanda R.; Anderson, Robert C.

2004-01-01

Over the past decade advanced optical diagnostic techniques have evolved and matured to a point where they are now widely applied in the interrogation of high pressure combusting flows. At NASA Glenn Research Center (GRC), imaging techniques have been used successfully in on-going work to develop the next generation of commercial aircraft gas turbine combustors. This work has centered on providing a means by which researchers and designers can obtain direct visual observation and measurements of the fuel injection/mixing/combustion processes and combustor flowfield in two- and three-dimensional views at actual operational conditions. Obtaining a thorough understanding of the chemical and physical processes at the extreme operating conditions of the next generation of combustors is critical to reducing emissions and increasing fuel efficiency. To accomplish this and other tasks, the diagnostic team at GRC has designed and constructed optically accessible, high pressurer high temperature flame tubes and sectar rigs capable of optically probing the 20-60 atm flowfields of these aero-combustors. Among the techniques employed at GRC are planar laser-induced fluorescence (PLIF) for imaging molecular species as well as liquid and gaseous fuel; planar light scattering (PLS) for imaging fuel sprays and droplets; and spontaneous Raman scattering for species and temperature measurement. Using these techniques, optical measurements never before possible have been made in the actual environments of liquid fueled gas turbines. 2-D mapping of such parameters as species (e.g. OH-, NO and kerosene-based jet fuel) distribution, injector spray angle, and fuel/air distribution are just some of the measurements that are now routinely made. Optical imaging has also provided prompt feedback to researchers regarding the effects of changes in the fuel injector configuration on both combustor performance and flowfield character. Several injector design modifications and improvements have

Researches on direct injection in internal-combustion engines

Science.gov (United States)

Tuscher, Jean E

1941-01-01

These researches present a solution for reducing the fatigue of the Diesel engine by permitting the preservation of its components and, at the same time, raising its specific horsepower to a par with that of carburetor engines, while maintaining for the Diesel engine its perogative of burning heavy fuel under optimum economical conditions. The feeding of Diesel engines by injection pumps actuated by engine compression achieves the required high speeds of injection readily and permits rigorous control of the combustible charge introduced into each cylinder and of the peak pressure in the resultant cycle.

Rates of fuel discharge as affected by the design of fuel-injection systems for internal-combustion engines

Science.gov (United States)

Gelalles, A G; Marsh, E T

1933-01-01

Using the method of weighing fuel collected in a receiver during a definite interval of the injection period, rates of discharge were determined, and the effects noted, when various changes were made in a fuel-injection system. The injection system consisted primarily of a by-pass controlled fuel pump and an automatic injection valve. The variables of the system studied were the pump speed, pump-throttle setting, discharge-orifice diameter, injection-valve opening and closing pressures, and injection-tube length and diameter.

Modeling and control of fuel distribution in a dual-fuel internal combustion engine leveraging late intake valve closings

Energy Technology Data Exchange (ETDEWEB)

Kassa, Mateos [Mechanical, Materials, and Aerospace Engineering Department, Illinois Institute of Technology, Chicago, IL, USA; Hall, Carrie [Mechanical, Materials, and Aerospace Engineering Department, Illinois Institute of Technology, Chicago, IL, USA; Ickes, Andrew [Fuels, Engine and Aftertreatment Research, Argonne National Laboratory, Argonne, IL, USA; Wallner, Thomas [Fuels, Engine and Aftertreatment Research, Argonne National Laboratory, Argonne, IL, USA

2016-10-07

Advanced internal combustion engines, although generally more efficient than conventional combustion engines, often encounter limitations in multi-cylinder applications due to variations in the combustion process encountered across cylinders and between cycles. This study leverages experimental data from an inline 6-cylinder heavy-duty dual fuel engine equipped with exhaust gas recirculation (EGR), a variable geometry turbocharger, and a fully-flexible variable intake valve actuation system to study cylinder-to-cylinder variations in power production and the underlying uneven fuel distribution that causes these variations. The engine is operated with late intake valve closure timings in a dual-fuel combustion mode in which a high reactivity fuel is directly injected into the cylinders and a low reactivity fuel is port injected into the cylinders. Both dual fuel implementation and late intake valve closing (IVC) timings have been shown to improve thermal efficiency. However, experimental data from this study reveal that when late IVC timings are used on a multi-cylinder dual fuel engine a significant variation in IMEP across cylinders results and as such, leads to efficiency losses. The difference in IMEP between the different cylinders ranges from 9% at an IVC of 570°ATDC to 38% at an IVC of 610°ATDC and indicates an increasingly uneven fuel distribution. These experimental observations along with engine simulation models developed using GT-Power have been used to better understand the distribution of the port injected fuel across cylinders under various operating conditions on such dual fuel engines. This study revealed that the fuel distribution across cylinders in this dual fuel application is significantly affected by changes in the effective compression ratio as determined by the intake valve close timing as well as the design of the intake system (specifically the length of the intake runners). Late intake valve closures allow a portion of the trapped air

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.

Effects of biobutanol and biobutanol–diesel blends on combustion and emission characteristics in a passenger car diesel engine with pilot injection strategies

International Nuclear Information System (INIS)

Yun, Hyuntae; Choi, Kibong; Lee, Chang Sik

2016-01-01

Highlights: • Effects of biobutanol blends on NOx and soot emission characteristics in a diesel engine. • Comparison of combustion characteristics between biobutanol and diesel fuels. • Effect of pilot injection on combustion and emissions reduction in a diesel engine. - Abstract: In this study, we investigated the effect of biobutanol and biobutanol–diesel blends on the combustion and emission characteristics in a four-cylinder compression ignition engine using pilot injection strategies. The test fuels were a mixture of 10% biobutanol and 90% conventional diesel (Bu10), 20% biobutanol and 80% diesel (Bu20), and 100% diesel fuel (Bu0) based on mass. To study the combustion and emission characteristics of the biobutanol blended fuels, we carried out experimental investigations under various pilot injection timings from BTDC 20° to BTDC 60° with constant main injection timing. As the butanol content in the blended fuel increased, the experimental results indicated that the ignition delay was longer than that of diesel fuel for all pilot injection timings. Also, the indicated specific fuel consumption (ISFC) of the blended fuels was higher than that of diesel at all test conditions. However, the exhaust temperature was lower than that of diesel at all injection timings. Nitrogen oxide (NOx), carbon monoxide (CO) and soot from Bu20 were lower than those from diesel fuel at all test conditions and hydrocarbons (HC) were higher than that from diesel.

Effects of ethanol added fuel on exhaust emissions and combustion in a premixed charge compression ignition diesel engine

Directory of Open Access Journals (Sweden)

Kim Yungjin

2015-01-01

Full Text Available The use of diesel engines for vehicle has been increasing recently due to its higher thermal efficiency and lower CO2 emission level. However, in the case of diesel engine, NOx increases in a high temperature combustion region and particulate matter is generated in a fuel rich region. Therefore, the technique of PCCI (premixed charge compression ignition is often studied to get the peak combustion temperature down and to make a better air-fuel mixing. However it also has got a limited operating range and lower engine power produced by the wall wetting and the difficulty of the ignition timing control. In this research, the effect of injection strategies on the injected fuel behavior, combustion and emission characteristics in a PCCI engine were investigated to find out the optimal conditions for fuel injection, and then ethanol blended diesel fuel was used to control the ignition timing. As a result, the combustion pressures and ROHR (rate of heat release of the blended fuel became lower, however, IMEP showed fewer differences. Especially in the case of triple injection, smoke could be reduced a little and NOx emission decreased a lot by using the ethanol blended fuel simultaneously without much decreasing of IMEP compared to the result of 100% diesel fuel.

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.

Fuel Combustion Laboratory | Transportation Research | NREL

Science.gov (United States)

Fuel Combustion Laboratory Fuel Combustion Laboratory NREL's Fuel Combustion Laboratory focuses on designs, using both today's technology and future advanced combustion concepts. This lab supports the combustion chamber platform for fuel ignition kinetics research, was acquired to expand the lab's

An investigation of the effects of spray angle and injection strategy on dimethyl ether (DME) combustion and exhaust emission characteristics in a common-rail diesel engine

Energy Technology Data Exchange (ETDEWEB)

Yoon, Seung Hyun; Cha, June Pyo [Graduate School of Hanyang University, Hanyang University, 17 Haengdang-dong, Sungdong-gu, Seoul, 133-791 (Korea); Lee, Chang Sik [Department of Mechanical Engineering, Hanyang University, 17 Haengdang-dong, Sungdong-gu, Seoul 133-791 (Korea)

2010-11-15

An experimental investigation was performed on the effects of spray angle and injection strategies (single and multiple) on the combustion characteristics, concentrations of exhaust emissions, and the particle size distribution in a direct-injection (DI) compression ignition engine fueled with dimethyl ether (DME) fuel. In this study, two types of narrow spray angle injectors ({theta}{sub spray} = 70 and 60 ) were examined and its results were compared with the results of conventional spray angle ({theta}{sub spray} = 156 ). In addition, to investigate the optimal operating conditions, early single-injection and multiple-injection strategies were employed to reduce cylinder wall-wetting of the injected fuels and to promote the ignition of premixed charge. The engine test was performed at 1400 rpm, and the injection timings were varied from TDC to BTDC 40 of the crank angle. The experimental results showed that the combustion pressure from single combustion for narrow-angle injectors ({theta}{sub spray} = 70 and 60 ) is increased, as compared to the results of the wide-angle injector ({theta}{sub spray} = 156 ) with advanced injection timing of BTDC 35 . In addition, two peaks of the rate of heat release (ROHR) are generated by the combustion of air-fuel premixed mixtures. DME combustion for all test injectors indicated low levels of soot emissions at all injection timings. The NO{sub x} emissions for narrow-angle injectors simultaneously increased in proportion to the advance in injection timing up to BTDC 25 , whereas BTDC 20 for the wide-angle injector. For multiple injections, the combustion pressure and ROHR of the first injection with narrow-angle injectors are combusted more actively, and the ignition delay of the second injected fuel is shorter than with the wide-angle injector. However, the second combustion pressure and ROHR were lower than during the first injection, and combustion durations are prolonged, as compared to the wide-angle injector. With

An investigation of the effects of spray angle and injection strategy on dimethyl ether (DME) combustion and exhaust emission characteristics in a common-rail diesel engine

International Nuclear Information System (INIS)

Yoon, Seung Hyun; Cha, June Pyo; Lee, Chang Sik

2010-01-01

An experimental investigation was performed on the effects of spray angle and injection strategies (single and multiple) on the combustion characteristics, concentrations of exhaust emissions, and the particle size distribution in a direct-injection (DI) compression ignition engine fueled with dimethyl ether (DME) fuel. In this study, two types of narrow spray angle injectors (θ spray = 70 and 60 ) were examined and its results were compared with the results of conventional spray angle (θ spray = 156 ). In addition, to investigate the optimal operating conditions, early single-injection and multiple-injection strategies were employed to reduce cylinder wall-wetting of the injected fuels and to promote the ignition of premixed charge. The engine test was performed at 1400 rpm, and the injection timings were varied from TDC to BTDC 40 of the crank angle. The experimental results showed that the combustion pressure from single combustion for narrow-angle injectors (θ spray = 70 and 60 ) is increased, as compared to the results of the wide-angle injector (θ spray = 156 ) with advanced injection timing of BTDC 35 . In addition, two peaks of the rate of heat release (ROHR) are generated by the combustion of air-fuel premixed mixtures. DME combustion for all test injectors indicated low levels of soot emissions at all injection timings. The NO x emissions for narrow-angle injectors simultaneously increased in proportion to the advance in injection timing up to BTDC 25 , whereas BTDC 20 for the wide-angle injector. For multiple injections, the combustion pressure and ROHR of the first injection with narrow-angle injectors are combusted more actively, and the ignition delay of the second injected fuel is shorter than with the wide-angle injector. However, the second combustion pressure and ROHR were lower than during the first injection, and combustion durations are prolonged, as compared to the wide-angle injector. With advanced timing of the first injection, narrow

Experimental Combustion Dynamics Behavior of a Multi-Element Lean Direct Injection (LDI) Gas Turbine Combustor

Science.gov (United States)

Acosta, Waldo A.; Chang, Clarence T.

2016-01-01

An experimental investigation of the combustion dynamic characteristics of a research multi-element lean direct injection (LDI) combustor under simulated gas turbine conditions was conducted. The objective was to gain a better understanding of the physical phenomena inside a pressurized flametube combustion chamber under acoustically isolated conditions. A nine-point swirl venturi lean direct injection (SV-LDI) geometry was evaluated at inlet pressures up to 2,413 kPa and non-vitiated air temperatures up to 867 K. The equivalence ratio was varied to obtain adiabatic flame temperatures between 1388 K and 1905 K. Dynamic pressure measurements were taken upstream of the SV-LDI, in the combustion zone and downstream of the exit nozzle. The measurements showed that combustion dynamics were fairly small when the fuel was distributed uniformly and mostly due to fluid dynamics effects. Dynamic pressure fluctuations larger than 40 kPa at low frequencies were measured at 653 K inlet temperature and 1117 kPa inlet pressure when fuel was shifted and the pilot fuel injector equivalence ratio was increased to 0.72.

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.

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.

Study on Combustion Oscillation of Premixed Flame with Pilot Fuel at Elevated Pressures

Science.gov (United States)

Ohtsuka, Masaya; Yoshida, Shohei; Hirata, Yoshitaka; Kobayashi, Nariyoshi

Acoustically-coupled combustion oscillation is studied for premixed flame with pilot fuel to be used in gas turbine combustors. Premixed gas is passed through swirl vanes and burnt with the centrally injected pilot fuel. The dependencies of pressure, fuel to air ratio, premixed fuel rate, inlet velocity and air temperature on the combustion oscillation are investigated. Two kinds of oscillation modes of ˜100Hz and ˜350Hz are activated according to inlet velocities. Fluctuating pressures are amplified when the premixed fuel rate is over ˜80% at elevated pressures. The fluctuating pressure peak moves to a higher premixed fuel ratio region with increased pressure or fuel to air ratio for the Helmholz type mode. Combustion oscillation occurs when the pilot fuel velocity is changed proportionally with the flame length.

Semi-volatile and particulate emissions from the combustion of alternative diesel fuels.

Science.gov (United States)

Sidhu, S; Graham, J; Striebich, R

2001-01-01

Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuel-rich conditions in the temperature range of 800-1200 degrees C at pressures of approximately 24 atm. A single pulse shock tube was used to simulate compression ignition (CI) combustion conditions. Gaseous fuels (CNG and DME) were exposed premixed in air while liquid fuels (diesel and biodiesel) were injected using a high-pressure liquid injector. The results of surface analysis using a scanning electron microscope showed that the particles formed from combustion of all four of the above-mentioned fuels had a mean diameter less than 0.1 microm. From results of gravimetric analysis and fuel injection size it was found that under the test conditions described above the relative particulate yields from CNG, DME, biodiesel, and diesel were 0.30%. 0.026%, 0.52%, and 0.51%, respectively. Chemical analysis of particles showed that DME combustion particles had the highest soluble organic fraction (SOF) at 71%, followed by biodiesel (66%), CNG (38%) and diesel (20%). This illustrates that in case of both gaseous and liquid fuels, oxygenated fuels have a higher SOF than non-oxygenated fuels.

EXPERIMENTAL COMBUSTION ANALYSIS OF A HSDI DIESEL ENGINE FUELLED WITH PALM OIL BIODIESEL-DIESEL FUEL BLENDS

Directory of Open Access Journals (Sweden)

JOHN AGUDELO

2009-01-01

Full Text Available Differences in the chemical nature between petroleum diesel fuels and vegetable oils-based fuels lead to differences in their physical properties affecting the combustion process inside the engine. In this work a detailed combustion diagnosis was applied to a turbocharged automotive diesel engine operating with neat palm oil biodiesel (POB, No. 2 diesel fuel and their blends at 20 and 50% POB by volume (B20 and B50 respectively. To isolate the fuel effect, tests were executed at constant power output without carrying out any modification of the engine or its fuel injection system. As the POB content in the blend increased, there was a slight reduction in the fuel/air equivalence ratio from 0.39 (B0 to 0.37 (B100, an advance of injection timing and of start of combustion. Additionally, brake thermal efficiency, combustion duration, maximum mean temperature, temperature at exhaust valve opening and exhaust gas efficiency decreased; while the peak pressure, exergy destruction rate and specific fuel consumption increased. With diesel fuel and the blends B20 and B50 the same combustion stages were noticed. However, as a consequence of the differences pointed out, the thermal history of the process was affected. The diffusion combustion stage became larger with POB content. For B100 no premixed stage was observed.

Physical and chemical effects of low octane gasoline fuels on compression ignition combustion

KAUST Repository

Badra, Jihad

2016-09-30

Gasoline compression ignition (GCI) engines running on low octane gasoline fuels are considered an attractive alternative to traditional spark ignition engines. In this study, three fuels with different chemical and physical characteristics have been investigated in single cylinder engine running in GCI combustion mode at part-load conditions both experimentally and numerically. The studied fuels are: Saudi Aramco light naphtha (SALN) (Research octane number (RON) = 62 and final boiling point (FBP) = 91 °C), Haltermann straight run naphtha (HSRN) (RON = 60 and FBP = 140 °C) and a primary reference fuel (PRF65) (RON = 65 and FBP = 99 °C). Injection sweeps, where the start of injection (SOI) is changed between −60 and −11 CAD aTDC, have been performed for the three fuels. Full cycle computational fluid dynamics (CFD) simulations were executed using PRFs as chemical surrogates for the naphtha fuels. Physical surrogates based on the evaporation characteristics of the naphtha streams have been developed and their properties have been implemented in the engine simulations. It was found that the three fuels have similar combustion phasings and emissions at the conditions tested in this work with minor differences at SOI earlier than −30 CAD aTDC. These trends were successfully reproduced by the CFD calculations. The chemical and physical effects were further investigated numerically. It was found that the physical characteristics of the fuel significantly affect the combustion for injections earlier than −30 CAD aTDC because of the low evaporation rates of the fuel because of the higher boiling temperature of the fuel and the colder in-cylinder air during injection. © 2016 Elsevier Ltd

Internal combustion engine using premixed combustion of stratified charges

Science.gov (United States)

Marriott, Craig D [Rochester Hills, MI; Reitz, Rolf D [Madison, WI

2003-12-30

During a combustion cycle, a first stoichiometrically lean fuel charge is injected well prior to top dead center, preferably during the intake stroke. This first fuel charge is substantially mixed with the combustion chamber air during subsequent motion of the piston towards top dead center. A subsequent fuel charge is then injected prior to top dead center to create a stratified, locally richer mixture (but still leaner than stoichiometric) within the combustion chamber. The locally rich region within the combustion chamber has sufficient fuel density to autoignite, and its self-ignition serves to activate ignition for the lean mixture existing within the remainder of the combustion chamber. Because the mixture within the combustion chamber is overall premixed and relatively lean, NO.sub.x and soot production are significantly diminished.

Co-combustion of biodiesel with oxygenated fuels in direct injection diesel engine

Directory of Open Access Journals (Sweden)

Tutak Wojciech

2017-01-01

Full Text Available The paper presents results of experimental investigation of cocombustion process of biodiesel (B100 blended with oxygenated fuels with 20% in volume. As the alternative fuels ware used hydrated ethanol, methanol, 1-butanol and 2-propanol. It was investigated the influence of used blends on operating parameters of the test engine and exhaust emission (NOx, CO, THC, CO2. It is observed that used blends are characterized by different impact on engine output power and its efficiency. Using biodiesel/alcohol blend it is possible to improve engine efficiency with small drop in indicated mean effective pressure (IMEP. Due to combustion characteristic of biodiesel/alcohol obtained a slightly larger specific NOx emission. It was also observed some differences in combustion phases due to various values of latent heat of evaporation of used alcohols and various oxygen contents. Test results confirmed that the combustion process occurring in the diesel engine powered by blend takes place in a shorter time than in the typical diesel engine.

Combustion characteristics of a charcoal slurry in a direct injection diesel engine and the impact on the injection system performance

International Nuclear Information System (INIS)

Soloiu, Valentin; Lewis, Jeffery; Yoshihara, Yoshinobu; Nishiwaki, Kazuie

2011-01-01

The paper presents the research results pertaining to the renewable biomass charcoal-diesel slurries and their use as alternative fuels for combustion in diesel generating plants. The utilization of charcoal slurry fuel aims to reduce diesel oil consumption and would decrease fossil green house emissions into the atmosphere. The paper investigates the formulation, emulsification, sprays, combustion, injection system operation, and subsequent wear with charcoal-diesel slurries. In the research, cedar wood chips were used for the production of charcoal to be emulsified with diesel oil. The slurry's viscosity of 27 cP achieved the target ( o C. Charcoal slurry displayed a high vaporization rate of 75% by wt. at 300 o C. Engine investigations showed that the top combustion pressure at 1200 rpm and 100% load (7.8 brake mean effective pressure (bmep)) was 79 bar for diesel fuel and 78 bar for the charcoal slurry fuel. From the injection and heat release history was found an ignition delay of 1.7 ms for diesel that increased to 2.1 ms for the slurry fuel. A higher net heat release for charcoal slurry was observed, up to 180 J/crank angle degrees (CAD) compared with the diesel at 145 J/CAD The maximum combustion temperature reached 2300 K for diesel and 2330 K for slurry. The heat fluxes for both fuels have similar values and trends during the entire cycle showing the good compatibility of charcoal slurry with a diesel type combustion and low soot radiation. The exhaust temperatures were about 40-50 o C higher for charcoal slurry at 19 o before top dead center (BTDC) injection timing. The engine's bsfc increased as expected due to the lower heating value of the slurry fuel. The smoke Bosch no. was lower for the slurry fuel at any load, and is believed that the oxygen from the charcoal had a beneficial effect. The measured emissions of slurry fuel were better at 13 o BTDC than those of diesel fuel with the original engine settings and the remaining 6-10% oxygen content in

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

Improvement of combustion in a direct injection diesel engine by the use of a combustion-hole injection nozzle; Kumiawase funko nozzle ni yoru chokusetsu funshashiki diesel engine no nensho kaizen

Energy Technology Data Exchange (ETDEWEB)

Shoji, T. [Mitsubishi Motors Corp., Tokyo (Japan); Kamimoto, T. [Tokyo Institute of Technology, Tokyo (Japan)

1998-04-25

Suppression of pre-mixed combustion and activation of diffusion combustion in DI diesel engines are known to be effective in reducing both NOx and fuel consumption. To achieve this concept, the authors have proposed a new type of fuel injection nozzle named combination-hole nozzle. This nozzle has very small holes with a diameter of 0.13 mm below (sub holes) for reducing ignition delay and normal holes (main holes) for keeping reasonable injection duration. The experiments conducted with a single cylinder research engine revealed that the combination-hole nozzle reduced the ignition delay and the peak value of the rate of heat release during the premixed combustion by 10% and 40% respectively compared with the experimental results of conventional nozzles and that the trade-off curve between NOx and fuel consumption sifted to the low level corner at half and full load conditions at a low engine speed. The reason for this improvement was investigated by the measurement of flame temperature distribution in the combustion chamber by means of the two colors method. The result revealed that the flame temperature in regions between sub and main hole`s flames of the nozzle was lower than that of the flames of a conventional nozzle at a full load and a low speed condition. 13 refs., 10 figs., 3 tabs.

Investigating the compression ignition combustion of multiple biodiesel/ULSD (ultra-low sulfur diesel) blends via common-rail injection

International Nuclear Information System (INIS)

Mangus, Michael; Kiani, Farshid; Mattson, Jonathan; Tabakh, Daniel; Petka, James; Depcik, Christopher; Peltier, Edward; Stagg-Williams, Susan

2015-01-01

Researchers across the globe are searching for energy sources to replace the petroleum-based fuels used by the transportation sector. A fuel of particular interest is biodiesel, produced from a diverse variety of feedstock oils with differing fuel properties that alter the operation and emissions of the engines using them. As biodiesel may be mixed with petroleum-based diesel, the fuel being used by a diesel engine may vary by both biodiesel blend percentage and source. Therefore, the influence of biodiesel properties as a function of blend is important to understand. In this study, four biodiesels, produced from palm, jatropha, soybean, and beef tallow, are tested with blends of petroleum diesel at ratios of 5%, 10%, 20%, and 50% biodiesel content. The results are compared with tests of neat diesel and each biodiesel. Using electronic injection, timing is modulated to normalize combustion phasing for all fuels tested to directly investigate the effects of biodiesel on combustion. Results indicate that fuel viscosity, energy content, and molecular structure have distinct influences on combustion that must be considered for engine calibration. When adjusted for combustion timing, biodiesel blends also showed a general decrease in NO x emissions compared to ultra-low sulfur diesel. - Highlights: • Biodiesel injection timing is adjusted to remove cetane number effect on combustion. • When combustion is normalized, biodiesel NO x emissions are lower than those of ULSD. • Four distinct biodiesels used in blends from 0% to 100% biodiesel/ULSD fraction. • Correlating fuel properties to combustion/emissions is useful for engine calibration

Fuel flexible distributed combustion for efficient and clean gas turbine engines

International Nuclear Information System (INIS)

Khalil, Ahmed E.E.; Gupta, Ashwani K.

2013-01-01

Highlights: • Examined distributed combustion for gas turbines applications using HiTAC. • Gaseous, liquid, conventional and bio-fuels are examined with ultra-low emissions. • Novel design of fuel flexibility without any atomizer for liquid fuel sprays. • Demonstrated fuel flexibility with emissions x and CO, low noise, enhanced stability, higher efficiency and alleviation of combustion instability. Distributed reaction conditions were achieved using swirl for desirable controlled mixing between the injected air, fuel and hot reactive gases from within the combustor prior to mixture ignition. In this paper, distributed combustion is further investigated using a variety of fuels. Gaseous (methane, diluted methane, hydrogen enriched methane and propane) and liquid fuels, including both traditional (kerosene) and alternate fuels (ethanol) that cover a wide range of calorific values are investigated with emphasis on pollutants emission and combustor performance with each fuel. For liquid fuels, no atomization or spray device was used. Performance evaluation with the different fuels was established to outline the flexibility of the combustor using a wide range of fuels of different composition, phase and calorific value with specific focus on ultra-low pollutants emission. Results obtained on pollutants emission and OH * chemiluminescence for the specific fuels at various equivalence ratios are presented. Near distributed combustion conditions with less than 8 PPM of NO emission were demonstrated under novel premixed conditions for the various fuels tested at heat (energy) release intensity (HRI) of 27 MW/m 3 -atm. and a rather high equivalence ratio of 0.6. Higher equivalence ratios lacked favorable distributed combustion conditions. For the same conditions, CO emission varied for each fuel; less than 10 ppm were demonstrated for methane based fuels, while heavier liquid fuels provided less than 40 ppm CO emissions. Lower emissions of NO ( x can be possible by

An innovative system for supplying air and fuel mixture to a combustion chamber of an engine

Science.gov (United States)

Saikumar, G. R. Bharath

2018-04-01

Conventional carburetors are being used since decades to ensure that the desired ratio of air and fuel enters the combustion chamber for combustion for the purpose of generating power in an Spark Ignition(SI) internal combustion engine. However to increase the efficiency, the carburetor system is gradually being replaced by fuel injection systems. Fuel injection systems use injectors to supply pressurized fuel into the combustion chamber. Owing to the high initial and maintenance cost, carburetors are still ruling in the low cost vehicle domain. An innovative concept is conceived, which is an alternative method to the carburetor system to supply the air and fuel mixture to a combustion chamber of an engine. This system comprises of an inner hollow cylinder with minute holes drilled along its length with an outer cylinder capable of sliding along its length or its longitudinal axis. This system is placed in the venturi instead of the conventional carburetor system. Fuel enters from the bottom inlet of the inner cylinder and flows out through the holes provided along its length. The fuel flow from the inner cylinder is dependent on the size and the number of holes exposed at that instance by the sliding outer cylinder which in turn is connected to the throttle or accelerator.

Analysis of Fuel Injection and Atomization of a Hybrid Air-Blast Atomizer.

Science.gov (United States)

Ma, Peter; Esclape, Lucas; Buschhagen, Timo; Naik, Sameer; Gore, Jay; Lucht, Robert; Ihme, Matthias

2015-11-01

Fuel injection and atomization are of direct importance to the design of injector systems in aviation gas turbine engines. Primary and secondary breakup processes have significant influence on the drop-size distribution, fuel deposition, and flame stabilization, thereby directly affecting fuel conversion, combustion stability, and emission formation. The lack of predictive modeling capabilities for the reliable characterization of primary and secondary breakup mechanisms is still one of the main issues in improving injector systems. In this study, an unstructured Volume-of-Fluid method was used in conjunction with a Lagrangian-spray framework to conduct high-fidelity simulations of the breakup and atomization processes in a realistic gas turbine hybrid air blast atomizer. Results for injection with JP-8 aviation fuel are presented and compared to available experimental data. Financial support through the FAA National Jet Fuel Combustion Program is gratefully acknowledged.

Reduced NOX combustion method

International Nuclear Information System (INIS)

Delano, M.A.

1991-01-01

This patent describes a method for combusting fuel and oxidant to achieve reduced formation of nitrogen oxides. It comprises: It comprises: heating a combustion zone to a temperature at least equal to 1500 degrees F.; injecting into the heated combustion zone a stream of oxidant at a velocity within the range of from 200 to 1070 feet per second; injecting into the combustion zone, spaced from the oxidant stream, a fuel stream at a velocity such that the ratio of oxidant stream velocity to fuel stream velocity does not exceed 20; aspirating combustion gases into the oxidant stream and thereafter intermixing the aspirated oxidant stream and fuel stream to form a combustible mixture; combusting the combustible mixture to produce combustion gases for the aspiration; and maintaining the fuel stream substantially free from contact with oxidant prior to the intermixture with aspirated oxidant

Combustion and emission characteristics of diesel engine fueled with diesel-like fuel from waste lubrication oil

International Nuclear Information System (INIS)

Wang, Xiangli; Ni, Peiyong

2017-01-01

Highlights: • 100% diesel-like fuel from waste lubricating oil was conducted in a diesel engine. • Good combustion and fuel economy are achieved without engine modifications. • Combustion duration of DLF is shorter than diesel. • NOx and smoke emissions with the DLF are slightly higher than pure diesel. - Abstract: Waste lubricant oil (WLO) is one of the most important types of the energy sources. WLO cannot be burned directly in diesel engines, but can be processed to be used as diesel-like fuel (DLF) to minimize its harmful effect and maximize its useful values. Moreover, there are some differences in physicochemical properties between WLO and diesel fuel. In order to identify the differences in combustion and emission performance of diesel engine fueled with the two fuels, a bench test of a single-cylinder direct injection diesel engine without any engine modification was investigated at four engine speeds and five engine loads. The effects of the fuels on fuel economic performance, combustion characteristics, and emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx) and smoke were discussed. The DLF exhibits longer ignition delay period and shorter combustion duration than diesel fuel. The test results indicate that the higher distillation temperatures of the DLF attribute to the increase of combustion pressure, temperature and heat release rate. The brake specific fuel consumption (BSFC) of the DLF compared to diesel is reduced by about 3% at 3000 rpm under light and medium loads. The DLF produces slightly higher NOx emissions at middle and heavy loads, somewhat more smoke emissions at middle loads, and notably higher HC and CO emissions at most measured points than diesel fuel. It is concluded that the DLF can be used as potential available fuel in high-speed diesel engines without any problems.

New concept for low emission diesel combustion. 2nd Report. Combustion improvement by applying EGR and oxygenated fuel; Teikogai diesel engine no nensho concept. EGR, gansanso nenryo ni yoru nensho kaizen

Energy Technology Data Exchange (ETDEWEB)

Yokota, H.; Nakajima, H.; Kakegawa, T. [Hino Motors, Ltd., Tokyo (Japan)

1998-05-01

Described herein are performance of a new concept of premixed, multiple injection combustion, in which part of the fuel is injected into the combustion chamber at the early stage and the remainder is injected in the ordinary manner, and characteristics of the exhaust gases. Also described are the effects of EGR and oxygenated fuel on reduced HC emissions and fuel consumption. The ordinary premixed, multiple injection combustion system has problems related to fuel efficiency, and HC and particulate missions. When combined with an EGR system, this system reduces HC emissions to one-third. MTBE shows an effect of improving fuel efficiency, when mixed with diesel fuel. No particulate matter is exhausted and fuel efficiency is improved by 6%, when MTBE is present in the fuel at 30% by weight. The pre-mixture is less homogeneous in the absence of EGR and oxygenated fuel, producing a luminous flame observed in the fuel-rich region. No such a flame is observed, when MTBE is added to the fuel and suction air temperature is increased to the level corresponding to that associated with EGR, conceivably resulting from increased suction air temperature and lower boiling point of MTBE, which together make the pre-mixture leaner and more homogeneous. 7 refs., 9 figs., 2 tabs.

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)

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.

Combustion Stratification for Naphtha from CI Combustion to PPC

KAUST Repository

Vallinayagam, R.

2017-03-28

This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed. At early SOI, combustion phasing depends on both intake air temperature and SOI. In order to match the combustion phasing (CA50) of diesel, the intake air temperature is increased to 90°C for naphtha. The combustion stratification from CI to PPC is also investigated for various level of dilution by displacing oxygen with nitrogen in the intake. The start of combustion (SOC) was delayed with the increase in dilution and to compensate for this, the intake air temperature is increased. The mixture homogeneity is enhanced for higher dilution due to longer ignition delay. The results show that high speed image is initially blue and then turned yellow, indicating soot formation and oxidation. The luminosity of combustion images decreases with early SOI and increased dilution. The images are processed to generate the level of stratification based on the image intensity. The level of stratification is same for diesel and naphtha at various SOI. When O concentration in the intake is decreased to 17.7% and 14

Combustion stratification for naphtha from CI combustion to PPC

NARCIS (Netherlands)

Vallinayagam, R.; Vedharaj, S.; An, Y.; Dawood, A.; Izadi Najafabadi, M.; Somers, L.M.T.; Johansson, B.H.

2017-01-01

This study demonstrated the change in combustion homogeneity from conventional diesel combustion via partially premixed combustion towards HCCI. Experiments are performed in an optical diesel engine at a speed of 1200 rpm with diesel fuel. Single injection strategy is employed and the fuel is

Reducing NOx emissions from a biodiesel-fueled engine by use of low-temperature combustion.

Science.gov (United States)

Fang, Tiegang; Lin, Yuan-Chung; Foong, Tien Mun; Lee, Chia-Fon

2008-12-01

Biodiesel is popularly discussed in many countries due to increased environmental awareness and the limited supply of petroleum. One of the main factors impacting general replacement of diesel by biodiesel is NOx (nitrogen oxides) emissions. Previous studies have shown higher NOx emissions relative to petroleum diesel in traditional direct-injection (DI) diesel engines. In this study, effects of injection timing and different biodiesel blends are studied for low load [2 bar IMEP (indicated mean effective pressure)] conditions. The results show that maximum heat release rate can be reduced by retarding fuel injection. Ignition and peak heat release rate are both delayed for fuels containing more biodiesel. Retarding the injection to post-TDC (top dead center) lowers the peak heat release and flattens the heat release curve. It is observed that low-temperature combustion effectively reduces NOx emissions because less thermal NOx is formed. Although biodiesel combustion produces more NOx for both conventional and late-injection strategies, with the latter leading to a low-temperature combustion mode, the levels of NOx of B20 (20 vol % soy biodiesel and 80 vol % European low-sulfur diesel), B50, and B100 all with post-TDC injection are 68.1%, 66.7%, and 64.4%, respectively, lower than pure European low-sulfur diesel in the conventional injection scenario.

Study on the combustion and hydrocarbon emission characteristics of direct injection spark-ignition engines during the direct-start process

International Nuclear Information System (INIS)

Shi, Lei; Xiao, Maoyu; Deng, Kangyao

2015-01-01

Highlights: • Mixture concentration in first-combustion cylinder of direct start is measured. • Factors that affect direct start performances are investigated. • Combustion characteristics of first-combustion cylinder are analyzed. • Hydrocarbon emission is considered to determined control strategies of direct start. - Abstract: This study was conducted to investigate the combustion and emissions characteristics of the first-combustion cylinder in a direct-start process. The explosive energy of the first combustion is important for the success of a direct start, but this combustion was rarely addressed in recent research. For a 2.0 L direct-injection spark-ignition engine, the in-cylinder mixture concentration, cylinder pressure, engine speed and exhaust hydrocarbon concentration were detected to analyze the fuel evaporation, combustion, engine movement and engine emissions, respectively. In the first-combustion cylinder of the direct-start process, the injected fuel was often enriched to ensure that an appropriate mixture concentration was obtained for ignition without misfiring. Approximately one-third of the injected fuel would not participate in the combustion process and would therefore reduce the exhaust hydrocarbon emissions. The start position determined the amount of the total explosive energy in the first-combustion cylinder, and an optimal start position for a direct start was found to be at a 70–80° crank angle before the top dead center to obtain a better combustion performance and lower emissions. A lower coolant temperature increased the maximum explosion energy of the first combustion, but additional hydrocarbon emissions were generated. Because there was almost no problem in the direct-start capability with different coolant temperatures after an idling stop, it was necessary to maintain the coolant temperature when the engine was stopped

Chemical Looping Combustion with Different Types of Liquid Fuels Combustion en boucle chimique avec différentes charges liquides

Directory of Open Access Journals (Sweden)

Hoteit A.

2011-02-01

Full Text Available CLC is a new promising combustion process for CO2 capture with less or even no energy penalty compared to other processes. Up to now, most of the work performed on CLC was conducted with gaseous or solid fuels, using methane and coal and/or pet coke. Liquid fuels such as heavy fuels resulting from oil distillation or conversion may also be interesting feedstocks to consider. However, liquid fuels are challenging feedstock to deal with in fluidized beds. The objective of the present work is therefore to investigate the feasibility of liquid feed injection and contact with oxygen carrier in CLC conditions in order to conduct partial or complete combustion of hydrocarbons. A batch experimental fluidized bed set-up was developed to contact alternatively oxygen carrier with liquid fuels or air. The 20 mm i.d. fluidized bed reactor was filled up with 45 g of NiAl0.44O1.67 and pulses of 1-2 g of liquid were injected in the bed at high temperatures up to 950˚C. Different feedstocks have been injected, from dodecane to heavy fuel oils No.2. Results show that, during the reduction period, it is possible to convert all the fuel injected and there is no coke remaining on particles at the end of the reduction step. Depending upon oxygen available in the bed, either full combustion or partial combustion can be achieved. Similar results were found with different liquid feeds, despite their different composition and properties. Le CLC est un nouveau concept prometteur appliqué à la combustion qui permet le captage de CO en minimisant la pénalité énergétique liée au captage. Jusqu’à présent, l’essentiel des travaux de recherche dans le domaine du CLC concerne les charges gazeuses (méthane et solides (charbon et coke. Les charges liquides, et particulièrement les résidus pétroliers, sont des charges également intéressantes à considérer a priori. La mise en oeuvre de ces charges en lit fluidisé est cependant délicate. L’objet de ce

The effects of de-humidification and O{sub 2} direct injection in oxy-PC combustion

Energy Technology Data Exchange (ETDEWEB)

Choi, C.G.; Na, I.H.; Lee, J.W.; Chae, T.Y.; Yang, W. [Korea Insitute of Industrial Technology, Seoul (Korea, Republic of). Energy System R and D Dept.

2013-07-01

This study is aimed to derive effects of de-humidification and O{sub 2} direct injection in oxy-PC combustion system. Temperature distribution and flue gas composition were observed for various air and oxy-fuel conditions such as effect of various O{sub 2} concentration of total oxidant, O{sub 2} concentration of primary stream and O{sub 2} direct injection through 0-D heat and mass balance calculation and experiments in the oxy-PC combustion system of 0.3 MW scale in KITECH (Korea Institute of Industrial Technology). Flame attachment characteristic related to O{sub 2} direct injection was also observed experimentally. We found that FEGT (furnace exit gas temperature) of 100% de-humidification to oxidizer is lower than humidification condition; difference between two conditions is lower than 20 C in all cases. The efficiency changing of combustion was negligible in O{sub 2} direct injection. But O{sub 2} direct injection should be carefully designed to produce a stable flame.

Ducted fuel injection

Energy Technology Data Exchange (ETDEWEB)

Mueller, Charles J.

2018-03-06

Various technologies presented herein relate to enhancing mixing inside a combustion chamber to form one or more locally premixed mixtures comprising fuel and charge-gas with low peak fuel to charge-gas ratios to enable minimal, or no, generation of soot and other undesired emissions during ignition and subsequent combustion of the locally premixed mixtures. To enable sufficient mixing of the fuel and charge-gas, a jet of fuel can be directed to pass through a bore of a duct causing charge-gas to be drawn into the bore creating turbulence to mix the fuel and the drawn charge-gas. The duct can be located proximate to an opening in a tip of a fuel injector. The duct can comprise of one or more holes along its length to enable charge-gas to be drawn into the bore, and further, the duct can cool the fuel and/or charge-gas prior to combustion.

Fuel and combustion stratification study of Partially Premixed Combustion

OpenAIRE

Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

2016-01-01

Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a clear definition of “fuel and combustion stratifications” is obvious in literature. Hence, it is difficult to compare stratification levels of different PPC strategies or other combustion concepts. T...

Electrically controlled fuel injection device for internal combustion engines with air quantity meter. Elektrisch gesteuerte Kraftstoffeinspritzeinrichtung fuer Brennkraftmaschinen mit Luftmengenmesser

Energy Technology Data Exchange (ETDEWEB)

Kraus, B; Soell, W

1980-12-11

The invention concerns an electrically controlled preferably intermittently working fuel injection device for internal combustion engines with a throttle valve, a solenoid operated injection valve and a transistor circuit, which supplies electrical pulses used to open the injection valve synchronously to the revolution of the crankshaft. The invention is characterized by the fact that an electrical control device is provided, which extends the individual opening pulses in thrust operation (with the throttle valve closed or nearly closed and with a working speed above the speed). The extension produced by the control device decreases from a value at about 20% for the maximum speed to a value of 0 for the tickover speed. Details of the transistor control are made clear by detailed circuit diagrams and 5 patent claims.

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.

On the effect of injection timing on the ignition of lean PRF/air/EGR mixtures under direct dual fuel stratification conditions

KAUST Repository

Luong, Minh Bau; Sankaran, Ramanan; Yu, Gwang Hyeon; Chung, Suk-Ho; Yoo, Chun Sang

2017-01-01

The ignition characteristics of lean primary reference fuel (PRF)/air/exhaust gas recirculation (EGR) mixture under reactivity-controlled compression ignition (RCCI) and direct duel fuel stratification (DDFS) conditions are investigated by 2-D direct numerical simulations (DNSs) with a 116-species reduced chemistry of the PRF oxidation. The 2-D DNSs of the DDFS combustion are performed by varying the injection timing of iso-octane (i-C8H18) with a pseudo-iso-octane (PC8H18) model together with a novel compression heating model to account for the compression heating and expansion cooling effects of the piston motion in an engine cylinder. The PC8H18 model is newly developed to mimic the timing, duration, and cooling effects of the direct injection of i-C8H18 onto a premixed background charge of PRF/air/EGR mixture with composition inhomogeneities. It is found that the RCCI combustion exhibits a very high peak heat release rate (HRR) with a short combustion duration due to the predominance of the spontaneous ignition mode of combustion. However, the DDFS combustion has much lower peak HRR and longer combustion duration regardless of the fuel injection timing compared to those of the RCCI combustion, which is primarily attributed to the sequential injection of i-C8H18. It is also found that the ignition delay of the DDFS combustion features a non-monotonic behavior with increasing fuel-injection timing due to the different effect of fuel evaporation on the low-, intermediate-, and high-temperature chemistry of the PRF oxidation. The budget and Damköhler number analyses verify that although a mixed combustion mode of deflagration and spontaneous ignition exists during the early phase of the DDFS combustion, the spontaneous ignition becomes predominant during the main combustion, and hence, the spread-out of heat release rate in the DDFS combustion is mainly governed by the direct injection process of i-C8H18. Finally, a misfire is observed for the DDFS combustion when

On the effect of injection timing on the ignition of lean PRF/air/EGR mixtures under direct dual fuel stratification conditions

KAUST Repository

Luong, Minh Bau

2017-06-10

The ignition characteristics of lean primary reference fuel (PRF)/air/exhaust gas recirculation (EGR) mixture under reactivity-controlled compression ignition (RCCI) and direct duel fuel stratification (DDFS) conditions are investigated by 2-D direct numerical simulations (DNSs) with a 116-species reduced chemistry of the PRF oxidation. The 2-D DNSs of the DDFS combustion are performed by varying the injection timing of iso-octane (i-C8H18) with a pseudo-iso-octane (PC8H18) model together with a novel compression heating model to account for the compression heating and expansion cooling effects of the piston motion in an engine cylinder. The PC8H18 model is newly developed to mimic the timing, duration, and cooling effects of the direct injection of i-C8H18 onto a premixed background charge of PRF/air/EGR mixture with composition inhomogeneities. It is found that the RCCI combustion exhibits a very high peak heat release rate (HRR) with a short combustion duration due to the predominance of the spontaneous ignition mode of combustion. However, the DDFS combustion has much lower peak HRR and longer combustion duration regardless of the fuel injection timing compared to those of the RCCI combustion, which is primarily attributed to the sequential injection of i-C8H18. It is also found that the ignition delay of the DDFS combustion features a non-monotonic behavior with increasing fuel-injection timing due to the different effect of fuel evaporation on the low-, intermediate-, and high-temperature chemistry of the PRF oxidation. The budget and Damköhler number analyses verify that although a mixed combustion mode of deflagration and spontaneous ignition exists during the early phase of the DDFS combustion, the spontaneous ignition becomes predominant during the main combustion, and hence, the spread-out of heat release rate in the DDFS combustion is mainly governed by the direct injection process of i-C8H18. Finally, a misfire is observed for the DDFS combustion when

Experimental investigations of the effect of pilot injection on performance, emissions and combustion characteristics of Karanja biodiesel fuelled CRDI engine

International Nuclear Information System (INIS)

Dhar, Atul; Agarwal, Avinash Kumar

2015-01-01

Highlights: • Effect of multiple injections on CRDI engine performance, emission and combustion. • Effect of multiple injections, injection pressures and injection timings on biodiesel. • Lower biodiesel blends showed lower BSCO, BSHC but higher BSNOx emissions. • Maximum cylinder pressure at higher FIP was higher at same SOPI and SOMI. • Combustion duration of KOME50 was higher than mineral diesel. - Abstract: Pilot and post injections are being used in modern diesel engines for improving engine performance in addition to meeting stringent emission norms. Biodiesel produced from different feedstocks is gaining global recognition as partial replacement for mineral diesel in compression ignition (CI) engines. In this study, 10%, 20% and 50% Karanja biodiesel blends were used for investigation of pilot injections, injection pressures and injection timings on biodiesel blends. Experiments were carried out in a single cylinder CRDI research engine in multiple injection mode at 500 and 1000 bar fuel injection pressure (FIP) under varying start of pilot injection (SOPI) and start of main injection (SOMI) timings. Brake specific fuel consumption (BSFC) increased with increasing Karanja biodiesel concentration in test fuels however brake thermal efficiency (BTE) of biodiesel blends was slightly higher than mineral diesel. Lower biodiesel blends showed lower brake specific carbon monoxide (BSCO) and brake specific hydrocarbon (BSHC) emissions than mineral diesel. Brake specific nitrogen oxides (BSNOx) emissions from KOME20 and KOME10 were higher than mineral diesel. Combustion duration of KOME50 was also higher than mineral diesel

Experimental investigation of timed manifold injection of acetylene in direct injection diesel engine in dual fuel mode

International Nuclear Information System (INIS)

Lakshmanan, T.; Nagarajan, G.

2010-01-01

The increase in demand and decrease in availability of fossil fuels with more stringent emission norms have led to research in finding an alternative fuel for internal combustion (IC) engines. Among the alternative fuels, gaseous fuels find a great potential. The gaseous fuel taken up for the present study is acetylene, which possesses excellent combustion properties. Preignition is the major problem with this fuel. In the present study, timed manifold injection technique is adopted to induct the fuel into the IC engine. A four-stroke, 4.4 kW diesel engine is selected, with slight modification in intake manifold for holding the gas injector, which is controlled by an electronic control unit (ECU). By using an ECU, an optimized injection timing of 10 o after top dead center and 90 o crank angle duration are arrived. At this condition, experiments were conducted for the various gas flow rates of 110 g/s, 180 g/s and 240 g/s. The performance was nearer to diesel at full load. Oxides of nitrogen, hydrocarbon and carbon monoxide emission decreased due to lean operation with marginal increase in smoke emission. To conclude, a safe operation of acetylene replacement up to 24% was possible with reduction in emission parameters.

Experimental Investigation of the Effect of Biodiesel Blends on a DI Diesel Engine’s Injection and Combustion

Directory of Open Access Journals (Sweden)

Dimitrios N Tziourtzioumis

2017-07-01

Full Text Available Differences in the evolution of combustion in a single cylinder, DI (direct injection diesel engine fuelled by B20 were observed upon processing of the respective indicator diagrams. Aiming to further investigate the effects of biodiesel on the engine injection and combustion process, the injection characteristics of B0, B20, B40, B60, B80 and B100 were measured at low injection pressure and visualized at low and standard injection pressures. The fuel atomization characteristics were investigated in terms of mean droplet velocity, Sauter mean diameter, droplet velocity and diameter distributions by using a spray visualization system and Laser Doppler Velocimetry. The jet break-up characteristics are mainly influenced by the Weber number, which is lower for biodiesel, mainly due to its higher surface tension. Thus, Sauter mean diameter (SMD of sprays with biodiesel blended-fuel is higher. Volume mean diameter (VMD and arithmetic mean diameter (AMD values also increase with blending ratio. Kinematic viscosity and surface tension become higher as the biodiesel blending ratio increases. The SMD, VMD and AMD of diesel and biodiesel blended fuels decreased with an increase in the axial distance from spray tip. Comparison of estimated fuel burning rates for 60,000 droplets’ samples points to a decrease in mean fuel burning rate for B20 and higher blends.

Experimental investigations of a single cylinder genset engine with common rail fuel injection system

Directory of Open Access Journals (Sweden)

Gupta Paras

2014-01-01

Full Text Available Performance and emissions characteristics of compression ignition (CI engines are strongly dependent on quality of fuel injection. In an attempt to improve engine combustion, engine performance and reduce the exhaust emissions from a single cylinder constant speed genset engine, a common rail direct injection (CRDI fuel injection system was deployed and its injection timings were optimized. Results showed that 34°CA BTDC start of injection (SOI timings result in lowest brake specific fuel consumption (BSFC and smoke opacity. Advanced injection timings showed higher cylinder peak pressure, pressure rise rate, and heat release rate due to relatively longer ignition delay experienced.

Injection system used into SI engines for complete combustion and reduction of exhaust emissions in the case of alcohol and petrol alcohol mixtures feed

Science.gov (United States)

Ispas, N.; Cofaru, C.; Aleonte, M.

2017-10-01

Internal combustion engines still play a major role in today transportation but increasing the fuel efficiency and decreasing chemical emissions remain a great goal of the researchers. Direct injection and air assisted injection system can improve combustion and can reduce the concentration of the exhaust gas pollutes. Advanced air-to-fuel and combustion air-to-fuel injection system for mixtures, derivatives and alcohol gasoline blends represent a major asset in reducing pollutant emissions and controlling combustion processes in spark-ignition engines. The use of these biofuel and biofuel blending systems for gasoline results in better control of spark ignition engine processes, making combustion as complete as possible, as well as lower levels of concentrations of pollutants in exhaust gases. The main purpose of this paper was to provide most suitable tools for ensure the proven increase in the efficiency of spark ignition engines, making them more environmentally friendly. The conclusions of the paper allow to highlight the paths leading to a better use of alcohols (biofuels) in internal combustion engines of modern transport units.

Numerical exploration of mixing and combustion in ethylene fueled scramjet combustor

Science.gov (United States)

Dharavath, Malsur; Manna, P.; Chakraborty, Debasis

2015-12-01

Numerical simulations are performed for full scale scramjet combustor of a hypersonic airbreathing vehicle with ethylene fuel at ground test conditions corresponding to flight Mach number, altitude and stagnation enthalpy of 6.0, 30 km and 1.61 MJ/kg respectively. Three dimensional RANS equations are solved along with species transport equations and SST-kω turbulence model using Commercial CFD software CFX-11. Both nonreacting (with fuel injection) and reacting flow simulations [using a single step global reaction of ethylene-air with combined combustion model (CCM)] are carried out. The computational methodology is first validated against experimental results available in the literature and the performance parameters of full scale combustor in terms of thrust, combustion efficiency and total pressure loss are estimated from the simulation results. Parametric studies are conducted to study the effect of fuel equivalence ratio on the mixing and combustion behavior of the combustor.

Effects of Injection Rate Profile on Combustion Process and Emissions in a Diesel Engine

Directory of Open Access Journals (Sweden)

Fuqiang Bai

2017-01-01

Full Text Available When multi-injection is implemented in diesel engine via high pressure common rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are the same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid, and wedge of injection rate profiles were investigated. Modeling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline, rectangle (flat, shape of injection rate can have better balance between NOx and soot emissions than the other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces the highest soot emissions among the five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions were produced by triangle shape due to higher peak injection rate.

Combustor nozzle for a fuel-flexible combustion system

Science.gov (United States)

Haynes, Joel Meier [Niskayuna, NY; Mosbacher, David Matthew [Cohoes, NY; Janssen, Jonathan Sebastian [Troy, NY; Iyer, Venkatraman Ananthakrishnan [Mason, OH

2011-03-22

A combustor nozzle is provided. The combustor nozzle includes a first fuel system configured to introduce a syngas fuel into a combustion chamber to enable lean premixed combustion within the combustion chamber and a second fuel system configured to introduce the syngas fuel, or a hydrocarbon fuel, or diluents, or combinations thereof into the combustion chamber to enable diffusion combustion within the combustion chamber.

Effect of injection timing on combustion and performance of a direct injection diesel engine running on Jatropha methyl ester

Energy Technology Data Exchange (ETDEWEB)

Jindal, S. [Mechanical Engineering Department, College of Technology & Engineering, Maharana Pratap University of Agriculture and Technology, Udaipur 313001 (India)

2011-07-01

The present study aims at evaluation of effect of injection timing on the combustion, performance and emissions of a small power diesel engine, commonly used for agriculture purpose, running on pure biodiesel, prepared from Jatropha (Jatropha curcas) vegetable oil. The effect of varying injection timing was evaluated in terms of thermal efficiency, specific fuel consumption, power and mean effective pressure, exhaust temperature, cylinder pressure, rate of pressure rise and the heat release rate. It was found that retarding the injection timing by 3 degrees enhances the thermal efficiency by about 8 percent.

Numerical simulation of fuel sprays and combustion in a premixed lean diesel engine; Kihaku yokongo diesel kikan ni okeru nenryo funmu to nensho no suchi simulation

Energy Technology Data Exchange (ETDEWEB)

Miyamoto, T; Harada, A; Sasaki, S; Shimazaki, N; Hashizume, T; Akagawa, H; Tsujimura, K

1997-10-01

Fuel sprays and combustion in a direct injection Premixed lean Diesel Combustion (PREDIC) engine, which can make smokeless combustion with little NOx emission, is studied numerically. Numerical simulation was carried out by means of KIVA II based computer code with a combustion submodel. The combustion submodel describes the formation of combustible fuel vapor by turbulent mixing and four-step chemical reaction which includes low temperature oxidation. Comparison between computation and experiment shows qualitatively good agreement in terms of heat release rate and NO emission. Computational results indicate that the combustion is significantly influenced by fuel spray characteristics and injection timing to vary NO emission. 10 refs., 8 figs., 1 tab.

Injection of heavy fuel oil into the blast furnace

Energy Technology Data Exchange (ETDEWEB)

Paloposki, T. [Helsinki Univ. of Technology, Otaniemi (Finland); Hakala, J.; Mannila, P.; Laukkanen, J. [Oulu Univ. (Finland)

1996-12-31

This study deals with the injection and combustion of heavy fuel oil in blast furnaces. The injection of the oil was studied experimentally in a small-scale test rig. The combustion of the oil was analysed with a commercial computer program for flow and combustion simulations. Results from computer simulations show that the combustion of the oil can be improved by decreasing the size of the oil drops and by enhancing the mixing between the oil drops and the hot blast. The devolatilization rate of the oil mainly depends on the size of the oil drops. The combustion rate of the volatiles mainly depends on the effectiveness of turbulent mixing with combustion air. Methods to decrease the size of the oil drops were sought in the experimental part of the study. Experimental results show that the size of the oil drops increases with increasing mass flow rate of the oil and decreases with increasing velocity of the hot blast. Methods to improve the mixing between the oil drops and the hot blast are suggested but have not yet been experimentally tested. (author) (4 refs.)

Injection of heavy fuel oil into the blast furnace

Energy Technology Data Exchange (ETDEWEB)

Paloposki, T [Helsinki Univ. of Technology, Otaniemi (Finland); Hakala, J; Mannila, P; Laukkanen, J [Oulu Univ. (Finland)

1997-12-31

This study deals with the injection and combustion of heavy fuel oil in blast furnaces. The injection of the oil was studied experimentally in a small-scale test rig. The combustion of the oil was analysed with a commercial computer program for flow and combustion simulations. Results from computer simulations show that the combustion of the oil can be improved by decreasing the size of the oil drops and by enhancing the mixing between the oil drops and the hot blast. The devolatilization rate of the oil mainly depends on the size of the oil drops. The combustion rate of the volatiles mainly depends on the effectiveness of turbulent mixing with combustion air. Methods to decrease the size of the oil drops were sought in the experimental part of the study. Experimental results show that the size of the oil drops increases with increasing mass flow rate of the oil and decreases with increasing velocity of the hot blast. Methods to improve the mixing between the oil drops and the hot blast are suggested but have not yet been experimentally tested. (author) (4 refs.)

Exhaust emissions from an indirect injection dual-fuel engine

International Nuclear Information System (INIS)

Abd Alla, G.H.; Badr, O.A.; Soliman, H.A.; Abd Rabbo, M.F.

2000-01-01

Diesel engines operating on gaseous fuels are commonly known as dual-fuel engines. In the present work, a single-cylinder, compression ignition, indirect injection research (Ricardo E6) engine has been installed at United Arab Emirates University for investigation of the exhaust emissions when the engine is operating as a dual-fuel engine. The influence of changes in major operating and design parameters, such as the concentration of gaseous fuel in the cylinder charge, pilot fuel quantity, injection timing and intake temperature, on the production of exhaust emissions was investigated. Diesel fuel was used as the pilot fuel, while methane or propane was used as the main fuel which was inducted in the intake manifold and mixed with the intake air. The experimental investigations showed that the poor emissions at light loads can be improved significantly by increasing the concentration of gaseous fuel (total equivalence ratio), employing a large pilot fuel quantity, advancing the injection timing of the pilot fuel and increasing the intake temperature. It is demonstrated that, in general, any measure that tends to increase the size of the combustion regions within the overly lean cylinder charge will reduce markedly the concentrations of unburned hydrocarbons and carbon monoxide in the exhaust gases. (Author)

Exhaust emissions from an indirect injection dual-fuel engine

Energy Technology Data Exchange (ETDEWEB)

Abd Alla, G.H.; Badr, O.A.; Soliman, H.A.; Abd Rabbo, M.F. [Zagazig Univ., Dept. of Mechanical Engineering, Cairo (Egypt)

2000-04-01

Diesel engines operating on gaseous fuels are commonly known as dual-fuel engines. In the present work, a single-cylinder, compression ignition, indirect injection research (Ricardo E6) engine has been installed at United Arab Emirates University for investigation of the exhaust emissions when the engine is operating as a dual-fuel engine. The influence of changes in major operating and design parameters, such as the concentration of gaseous fuel in the cylinder charge, pilot fuel quantity, injection timing and intake temperature, on the production of exhaust emissions was investigated. Diesel fuel was used as the pilot fuel, while methane or propane was used as the main fuel which was inducted in the intake manifold and mixed with the intake air. The experimental investigations showed that the poor emissions at light loads can be improved significantly by increasing the concentration of gaseous fuel (total equivalence ratio), employing a large pilot fuel quantity, advancing the injection timing of the pilot fuel and increasing the intake temperature. It is demonstrated that, in general, any measure that tends to increase the size of the combustion regions within the overly lean cylinder charge will reduce markedly the concentrations of unburned hydrocarbons and carbon monoxide in the exhaust gases. (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.

Turbulence-combustion interaction in direct injection diesel engine

Directory of Open Access Journals (Sweden)

Bencherif Mohamed

2014-01-01

Full Text Available The experimental measures of chemical species and turbulence intensity during the closed part of the engine combustion cycle are today unattainable exactly. This paper deals with numerical investigations of an experimental direct injection Diesel engine and a commercial turbocharged heavy duty direct injection one. Simulations are carried out with the kiva3v2 code using the RNG (k-ε model. A reduced mechanism for n-heptane was adopted for predicting auto-ignition and combustion processes. From the calibrated code based on experimental in-cylinder pressures, the study focuses on the turbulence parameters and combustion species evolution in the attempt to improve understanding of turbulence-chemistry interaction during the engine cycle. The turbulent kinetic energy and its dissipation rate are taken as representative parameters of turbulence. The results indicate that chemistry reactions of fuel oxidation during the auto-ignition delay improve the turbulence levels. The peak position of turbulent kinetic energy coincides systematically with the auto-ignition timing. This position seems to be governed by the viscous effects generated by the high pressure level reached at the auto-ignition timing. The hot regime flame decreases rapidly the turbulence intensity successively by the viscous effects during the fast premixed combustion and heat transfer during other periods. It is showed that instable species such as CO are due to deficiency of local mixture preparation during the strong decrease of turbulence energy. Also, an attempt to build an innovative relationship between self-ignition and maximum turbulence level is proposed. This work justifies the suggestion to determine otherwise the self-ignition timing.

EMISSION AND COMBUSTION CHARACTERISTICS OF DIFFERENT FUELS IN A HCCI ENGINE

OpenAIRE

S. Sendilvelan; S.Mohanamurugan

2011-01-01

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 combus...

Combustion and exhaust emission characteristics of a dual fuel compression ignition engine operated with pilot Diesel fuel and natural gas

International Nuclear Information System (INIS)

Papagiannakis, R.G.; Hountalas, D.T.

2004-01-01

Towards the effort of reducing pollutant emissions, especially soot and nitrogen oxides, from direct injection Diesel engines, engineers have proposed various solutions, one of which is the use of a gaseous fuel as a partial supplement for liquid Diesel fuel. These engines are known as dual fuel combustion engines, i.e. they use conventional Diesel fuel and a gaseous fuel as well. This technology is currently reintroduced, associated with efforts to overcome various difficulties of HCCI engines, using various fuels. The use of natural gas as an alternative fuel is a promising solution. The potential benefits of using natural gas in Diesel engines are both economical and environmental. The high autoignition temperature of natural gas is a serious advantage since the compression ratio of conventional Diesel engines can be maintained. The present contribution describes an experimental investigation conducted on a single cylinder DI Diesel engine, which has been properly modified to operate under dual fuel conditions. The primary amount of fuel is the gaseous one, which is ignited by a pilot Diesel liquid injection. Comparative results are given for various engine speeds and loads for conventional Diesel and dual fuel operation, revealing the effect of dual fuel combustion on engine performance and exhaust emissions

Numerical Analysis of the Combustion and Emission Characteristics of Diesel Engines with Multiple Injection Strategies Using a Modified 2-D Flamelet Model

Directory of Open Access Journals (Sweden)

Gyujin Kim

2017-08-01

Full Text Available The multiple injection strategy has been widely used in diesel engines to reduce engine noise, NOx and soot formation. Fuel injection developments such as the common-rail and piezo-actuator system provide more precise control of the injection quantity and time under higher injection pressures. As various injection strategies become accessible, it is important to understand the interaction of each fuel stream and following combustion process under the multiple injection strategy. To investigate these complex processes quantitatively, numerical analysis using CFD is a good alternative to overcome the limitation of experiments. A modified 2-D flamelet model is further developed from previous work to model multi-fuel streams with higher accuracy. The model was validated under various engine operating conditions and captures the combustion and emissions characteristics as well as several parametric variations. The model is expected to be used to suggest advanced injection strategies in engine development processes.

Diesel Combustion and Emission Using High Boost and High Injection Pressure in a Single Cylinder Engine

Science.gov (United States)

Aoyagi, Yuzo; Kunishima, Eiji; Asaumi, Yasuo; Aihara, Yoshiaki; Odaka, Matsuo; Goto, Yuichi

Heavy-duty diesel engines have adopted numerous technologies for clean emissions and low fuel consumption. Some are direct fuel injection combined with high injection pressure and adequate in-cylinder air motion, turbo-intercooler systems, and strong steel pistons. Using these technologies, diesel engines have achieved an extremely low CO2 emission as a prime mover. However, heavy-duty diesel engines with even lower NOx and PM emission levels are anticipated. This study achieved high-boost and lean diesel combustion using a single cylinder engine that provides good engine performance and clean exhaust emission. The experiment was done under conditions of intake air quantity up to five times that of a naturally aspirated (NA) engine and 200MPa injection pressure. The adopted pressure booster is an external supercharger that can control intake air temperature. In this engine, the maximum cylinder pressure was increased and new technologies were adopted, including a monotherm piston for endurance of Pmax =30MPa. Moreover, every engine part is newly designed. As the boost pressure increases, the rate of heat release resembles the injection rate and becomes sharper. The combustion and brake thermal efficiency are improved. This high boost and lean diesel combustion creates little smoke; ISCO and ISTHC without the ISNOx increase. It also yields good thermal efficiency.

Effects of Oxygen Content of Fuels on Combustion and Emissions of Diesel Engines

Directory of Open Access Journals (Sweden)

Haiwen Song

2016-01-01

Full Text Available Effects of oxygen content of fuels on combustion characteristics and emissions were investigated on both an optical single cylinder direct injection (DI diesel engine and a multi-cylinder engine. Three fuels were derived from conventional diesel fuel (Finnish City diesel summer grade by blending Rapeseed Methyl Ester (RME or Diglyme and Butyl-Diglyme of different quantities to make their oxygen content 3%, 3% and 9%, respectively. The experimental results with three tested fuels show that the fuel spray development was not affected apparently by the oxygenating. Compared with the base fuel, the ignition delay to pilot injection was shortened by 0%, 11% and 19% for three oxygenated fuels, respectively. The ignition delay to main injection was shortened by 10%, 19% and 38%, respectively. With regard to emissions, the smoke level was reduced by 24% to 90%, depending on fuel properties and engine running conditions. The penalties of increased NOx emissions and fuel consumption were up to 19% and 24%, respectively.

Research on the combustion, energy and emission parameters of diesel fuel and a biomass-to-liquid (BTL) fuel blend in a compression-ignition engine

International Nuclear Information System (INIS)

Rimkus, Alfredas; Žaglinskis, Justas; Rapalis, Paulius; Skačkauskas, Paulius

2015-01-01

Highlights: • Researched physical–chemical and performance properties of diesel fuel and BTL blend (85/15 V/V). • BTL additive reduced Brake Specific Fuel Consumption, improved engine efficiency. • Simpler BTL molecular chains and lower C/H ratio reduced CO_2 emission and smokiness. • Higher cetane number of BTL reduced heat release in beginning of combustion and NO_x emission. • Advanced start of fuel injection caused reduced fuel consumption and smokiness, increased NO_x emission. - Abstract: This paper presents the comparable research results of the physical–chemical and direct injection (DI) diesel engine properties of diesel fuel and BTL (biomass-to-liquid) blend (85/15 V/V). The energy, ecological and in-cylinder parameters were analysed under medium engine speed and brake torque load regimes; the start of fuel injection was also adjusted. After analysis of the engine bench tests and simulation with AVL BOOST software, it was observed that the BTL additive shortened the fuel ignition delay phase, reduced the heat release in the pre-mixed intensive combustion phase, reduced the nitrogen oxide (NO_x) concentration in the engine exhaust gases and reduced the thermal and mechanical load of the crankshaft mechanism. BTL additive reduced the rates of carbon dioxide (CO_2), incompletely burned hydrocarbons (HC) emission and smokiness due to its chemical composition and combustion features. BTL also reduced Brake Specific Fuel Consumption (BSFC, g/kW h) and improved engine efficiency (η_e); however, the volumetric fuel consumption changed due to the lower density of BTL. The start of fuel injection was adjusted for maximum engine efficiency; concomitantly, reductions in the CO_2 concentration, HC concentration and smokiness were achieved. However, the NO_x and thermo-mechanical engine load increased.

Auto-Ignition and Combustion of Diesel Fuel in a Constant-Volume Bomb

Science.gov (United States)

Selden, Robert F

1938-01-01

Report presents the results of a study of variations in ignition lag and combustion associated with changes in air temperature and density for a diesel fuel in a constant-volume bomb. The test results have been discussed in terms of engine performance wherever comparisons could be drawn. The most important conclusions drawn from this investigation are: the ignition lag was essentially independent of the injected fuel quantity. Extrapolation of the curves for the fuel used shows that the lag could not be greatly decreased by exceeding the compression-ignition engines. In order to obtain the best combustion and thermal efficiency, it was desirable to use the longest ignition lag consistent with a permissible rate of pressure rise.

Comprehensive study of biodiesel fuel for HSDI engines in conventional and low temperature combustion conditions

Energy Technology Data Exchange (ETDEWEB)

Tormos, Bernardo; Novella, Ricardo; Garcia, Antonio; Gargar, Kevin [CMT-Motores Termicos, Universidad Politecnica de Valencia, Valencia, ES, Campus de Vera, s/n, Edificio 6D. Camino de Vera s/n, 46022 Valencia (Spain)

2010-02-15

In this research, an experimental investigation has been performed to give insight into the potential of biodiesel as an alternative fuel for High Speed Direct Injection (HSDI) diesel engines. The scope of this work has been broadened by comparing the combustion characteristics of diesel and biodiesel fuels in a wide range of engine loads and EGR conditions, including the high EGR rates expected for future diesel engines operating in the low temperature combustion (LTC) regime. The experimental work has been carried out in a single-cylinder engine running alternatively with diesel and biodiesel fuels. Conventional diesel fuel and neat biodiesel have been compared in terms of their combustion performance through a new methodology designed for isolating the actual effects of each fuel on diesel combustion, aside from their intrinsic differences in chemical composition. The analysis of the results has been sequentially divided into two progressive and complementary steps. Initially, the overall combustion performance of each fuel has been critically evaluated based on a set of parameters used as tracers of the combustion quality, such as the combustion duration or the indicated efficiency. With the knowledge obtained from this previous overview, the analysis focuses on the detailed influence of biodiesel on the different diesel combustion stages known ignition delay, premixed combustion and mixing controlled combustion, considering also the impact on CO and UHC (unburn-hydrocarbons) pollutant emissions. The results of this research explain why the biodiesel fuel accelerates the diesel combustion process in all engine loads and EGR rates, even in those corresponding with LTC conditions, increasing its possibilities as alternative fuel for future DI diesel engines. (author)

Effects of MTBE blended diesel fuel on diesel combustion and emissions; MTBE kongo keiyu ga diesel nensho haiki ni oyobosu eikyo

Energy Technology Data Exchange (ETDEWEB)

Shundo, S; Yokota, H; Kakegawa, T [Hino Motors, Ltd., Tokyo (Japan)

1997-10-01

The effects of MTBE (Methyl-t-butyl ether) blended diesel fuel on diesel combustion and emissions were studied. In conventional diesel combustion, the testing mode was carried out in conformity with the Japanese 13 mode. Furthermore, this fuel was applied to a new combustion system (Homogeneous Charge Intelligent Multiple Injection). MTBE blended diesel fuel is more effective in the case of new combustion system and very low NOx, PM capability is suggested. 6 refs., 6 figs., 2 tabs.

Influence of the technique for injection of flue gas and the configuration of the swirl burner throat on combustion of gaseous fuel and formation of nitrogen oxides in the flame

Science.gov (United States)

Dvoinishnikov, V. A.; Khokhlov, D. A.; Knyaz'kov, V. P.; Ershov, A. Yu.

2017-05-01

How the points at which the flue gas was injected into the swirl burner and the design of the burner outlet influence the formation and development of the flame in the submerged space, as well as the formation of nitrogen oxides in the combustion products, have been studied. The object under numerical investigation is the flame of the GMVI combined (oil/gas) burner swirl burner fitted with a convergent, biconical, cylindrical, or divergent throat at the burner outlet with individual supply of the air and injection of the gaseous fuel through tubing. The burners of two designs were investigated; they differ by the absence or presence of an inlet for individual injection of the flue gas. A technique for numerical simulation of the flame based on the CFD methods widely used in research of this kind underlies the study. Based on the summarized results of the numerical simulation of the processes that occur in jet flows, the specific features of the aerodynamic pattern of the flame have been established. It is shown that the flame can be conventionally divided into several sections over its length in all investigations. The lengths of each of the sections, as well as the form of the fields of axial velocity, temperatures, concentrations of the fuel, oxygen, and carbon and nitrogen oxides, are different and determined by the design features of the burner, the flow rates of the agent, and the compositions of the latter in the burner ducts as well as the configuration of the burner throat and the temperature of the environment. To what degree the burner throat configuration and the techniques for injection of the flue gas at different ambient temperatures influence the formation of nitrogen oxides has been established. It is shown that the supply of the recirculation of flue gas into the fuel injection zone enables a considerable reduction in the formation of nitrogen oxides in the flame combustion products. It has been established that the locations of the zones of

Experimental and theoretical analysis of the combustion process at low loads of a diesel natural gas dual-fuel engine

International Nuclear Information System (INIS)

Li, Weifeng; Liu, Zhongchang; Wang, Zhongshu

2016-01-01

To construct an effective method to analyze the combustion process of dual fuel engines at low loads, effects of combustion boundaries on the combustion process of an electronically controlled diesel natural gas dual-fuel engine at low loads were investigated. Three typical combustion modes, including h, m and n, appeared under different combustion boundaries. In addition, the time-sequenced characteristic and the heat release rate-imbalanced characteristic were found in the dual fuel engine combustion process. To quantify these characteristics, two quantitative indicators, including the TSC (time-sequenced coefficient) and the HBC (HRR-balanced coefficient) were defined. The results show that increasing TSC and HBC can decrease HC (hydrocarbon) emissions and improve the BTE (brake thermal efficiency) significantly. The engine with the n combustion mode can obtain the highest BTE and the lowest HC emissions, followed by m, and then h. However, the combustion process of the engine will deteriorate sharply if boundary conditions are not strictly controlled in the n combustion mode. Based on the n combustion mode, advancing the start of diesel injection significantly, using large EGR (exhaust gas recirculation) rate and appropriately intake throttling can effectively reduce HC emissions and improve the BTE of dual fuel engines at low loads with relatively high natural gas PES (percentage energy substitution). - Highlights: • We reported three typical combustion modes of a dual-fuel engine at low loads. • Time-sequenced characteristic was put forward and qualified. • HRR-imbalanced characteristic was put forward and qualified. • Three combustion modes appeared as equivalence ratio/diesel injection timing varied. • The engine performance varied significantly with different combustion mode.

Fuels Combustion Research: Supercritical Fuel Pyrolysis

National Research Council Canada - National Science Library

Glassman, Irvin

2001-01-01

.... The focus during the subject period was directed to understanding the pyrolysis and combustion of endothermic fuels under subcritical conditions and the pyrolysis of these fuels under supercritical conditions...

Fuels Combustion Research: Supercritical Fuel Pyrolysis

National Research Council Canada - National Science Library

Glassman, Irvin

2000-01-01

.... The focus during the subject period was directed to understanding the pyrolysis and combustion of endothermic fuels under subcritical conditions and the pyrolysis of these fuels under supercritical conditions...

Investigation of High Pressure, Multi-Hole Diesel Fuel Injection Using High Speed Imaging

Science.gov (United States)

Morris, Steven; Eagle, Ethan; Wooldridge, Margaret

2012-10-01

Research to experimentally capture and understand transient fuel spray behavior of modern fuel injection systems remains underdeveloped. To this end, a high-pressure diesel common-rail fuel injector was instrumented in a spherical, constant volume combustion chamber to image the early time history of injection of diesel fuel. The research-geometry fuel injector has four holes aligned on a radial plane of the nozzle with hole sizes of 90, 110, 130 and 150 μm in diameter. Fuel was injected into a non-reacting environment with ambient densities of 17.4, 24.0, and 31.8 kg/m3 at fuel rail pressures of 1000, 1500, and 2000 bar. High speed images of fuel injection were taken using backlighting at 100,000 frames per second (100 kfps) and an image processing algorithm. The experimental results are compared with a one-dimensional fuel-spray model that was historically developed and applied to fuel sprays from single-hole fuel injectors. Fuel spray penetration distance was evaluated as a function of time for the different injector hole diameters, fuel injection pressures and ambient densities. The results show the differences in model predictions and experimental data at early times in the spray development.

Effect of ethanol/water blends addition on diesel fuel combustion in RCM and DI diesel engine

International Nuclear Information System (INIS)

Nour, Mohamed; Kosaka, Hidenori; Sato, Susumu; Bady, Mahmoud; Abdel-Rahman, Ali K.; Uchida, Kenta

2017-01-01

Highlights: • Effect of ethanol/water addition on diesel combustion studied using optical diagnostics. • The addition of water to ethanol improves engine combustion and soot oxidation. • Ethanol/water injection into exhaust manifold eliminates their endothermic effect. • Ethanol with high water content is recommended for better engine combustion. • Soot concentration reduced by 50% and NO x emissions reduced by 88%. - Abstract: The effect of ethanol/water blends addition on diesel fuel combustion and emissions is investigated experimentally in this study using optical diagnostics. Basic study is performed using rapid compression machine (RCM) under CI conditions. The tested ethanol energy fractions varied in the range of 10–40% of the total added fuel energy, while water volume ratios varied in the range of 10–40% of the injected ethanol. Ethanol and water were evaporated before entering the combustion chamber to eliminate their endothermic effect. Results reveal that addition of ethanol/water blends to diesel fuel results in longer ignition delay and promote the apparent heat release rate (AHRR) at the premixed combustion phase compared to absolute ethanol addition. Additionally, soot and NO x emissions are reduced with ethanol/water addition compared to absolute ethanol addition and neat diesel combustion. The basic study is then extended to investigate the effect ethanol/water blends addition on diesel fuel combustion using single cylinder diesel engine. Waste heat in exhaust manifold is utilized to vaporize ethanol/water blends before combustion. Results reveal that ethanol/water blends injection leads to increase in peak cylinder pressure, indicated mean effective pressure (IMEP), and AHRR at premixed combustion phase. Additionally, the ignition delay increased with ethanol/water addition. NO x emission is decreased up to 88% along with a reduction in soot by 50%. The lower ethanol to water volume ratios show better combustion efficiency, IMEP

Research into three-component biodiesel fuels combustion process using a single droplet technique

Directory of Open Access Journals (Sweden)

L. Raslavičius

2007-12-01

Full Text Available In order to reduce the engine emission while at same time improving engine efficiency, it is very important to clarify the combustion mechanism. Even if, there are many researches into investigating the mechanism of engine combustion, so that to clarify the relationship between complicated phenomena, it is very difficult to investigate due to the complicated process of both physical and chemical reaction from the start of fuel injection to the end of combustion event. The numerical simulations are based on a detailed vaporization model and detailed chemical kinetics. The influence of different physical parameters like droplet temperature, gas phase temperature, ambient gas pressure and droplet burning velocity on the ignition delay process is investigated using fuel droplet combustion stand. Experimental results about their influence on ignition delay time were presented.

A Comparison of Combustion Dynamics for Multiple 7-Point Lean Direct Injection Combustor Configurations

Science.gov (United States)

Tacina, K. M.; Hicks, Y. R.

2017-01-01

The combustion dynamics of multiple 7-point lean direct injection (LDI) combustor configurations are compared. LDI is a fuel-lean combustor concept for aero gas turbine engines in which multiple small fuel-air mixers replace one traditionally-sized fuel-air mixer. This 7-point LDI configuration has a circular cross section, with a center (pilot) fuel-air mixer surrounded by six outer (main) fuel-air mixers. Each fuel-air mixer consists of an axial air swirler followed by a converging-diverging venturi. A simplex fuel injector is inserted through the center of the air swirler, with the fuel injector tip located near the venturi throat. All 7 fuel-air mixers are identical except for the swirler blade angle, which varies with the configuration. Testing was done in a 5-atm flame tube with inlet air temperatures from 600 to 800 F and equivalence ratios from 0.4 to 0.7. Combustion dynamics were measured using a cooled PCB pressure transducer flush-mounted in the wall of the combustor test section.

Experimental study on the impact of operating conditions and fuel composition on PCCI combustion

Energy Technology Data Exchange (ETDEWEB)

Leermakers, C.A.J.

2010-03-15

Premixed Charge Compression Ignition (PCCI) is a combustion concept that holds the promise of combining emission levels of a spark-ignition (SI) engine with the efficiency of a compressionignition (CI) engine. In a short term scenario, PCCI combustion will be used in the low load part of the engine operating range only. This would guarantee low engine-out emission levels at operating conditions where exhaust temperatures are too low for effective NOx reduction through catalytic after treatment. At higher loads, the engine would run in conventional CI combustion mode, with emission requirements met through catalytic NOx reduction. Implicit with this scenario is that engine hardware design would be very close to that of current modern diesel engines. Compression ratio could be made load dependent through implementation of variable valve actuation. The PCCI experiments presented here have been performed using a modified 6 cylinder 12.6 liter heavy duty DI DAF XE 355 C engine. Experiments are conducted in one dedicated cylinder, which is equipped with a stand-alone fuel injection system, EGR circuit, and air compressor. For the low to medium load operating range the compression ratio has been lowered to 12:1 by means of a thicker head gasket. As engine hardware should - in the short term - preferably remain close to current diesel engines, optimizing operating conditions should focus on parameters like EGR level, intake temperature, intake pressure and injection timing. While past work in the Combustion Technology group has focused on low load PCCI combustion, in this report the effects on engine performance and emission behavior are investigated for both low and medium load PCCI combustion, up to 40% of full load. In the interpretation of experimental results, emphasis lies on the effect on combustion phasing and maximum pressure rise rate, which are inherent challenges to enable viable PCCI combustion. As in the short term scenario fuels will be used that are not too

Thermodynamic modeling of LPG combustion in dual-fuel engines; Modelisation thermodynamique de la combustion du GPL dans les moteurs dual-fuel

Energy Technology Data Exchange (ETDEWEB)

Bilcan, A.; Le Corre, O.; Tazerout, M. [Ecole des Mines de Nantes, 44 (France); Ramesh, A. [Indian Institute of Technology Madras (India)

2002-07-01

Dual-fuel engines are modified diesel engines burning simultaneously two fuels inside the cylinder: a gaseous one, called the primary fuel and a liquid one, called the pilot fuel. The thermal efficiency of the dual-fuel engine and of the diesel engine are comparable; the level of emissions is lower compared to the diesel one. This article presents a new procedure for the combustion modeling in a LPG-diesel dual-fuel engine. The procedures deals with the ignition delay period and with the rate of heat release inside the cylinder. This procedure is validated using experimental data issued front a collaboration with the Indian Institute of Technology from Madras, India. The used engine is a single-cylinder one, air-cooled. The pilot fuel is direct injected inside the cylinder The engine was run at constant load and with different diesel substitutions, i.e. for different air to fuel ratios of the primary fuel-air mixture. The general error of the procedure is below 10%. (authors)

Theoretical study of the effects of pilot fuel quantity and its injection timing on the performance and emissions of a dual fuel diesel engine

International Nuclear Information System (INIS)

Papagiannakis, R.G.; Hountalas, D.T.; Rakopoulos, C.D.

2007-01-01

Various solutions have been proposed for improving the combustion process of conventional diesel engines and reducing the exhaust emissions without making serious modifications on the engine, one of which is the use of natural gas as a supplement for the conventional diesel fuel, the so called dual fuel natural gas diesel engines. The most common type of these is referred to as the pilot ignited natural gas diesel engine (PINGDE). Here, the primary fuel is natural gas that controls the engine power output, while the pilot diesel fuel injected near the end of the compression stroke auto-ignites and creates ignition sources for the surrounding gaseous fuel mixture to be burned. Previous research studies have shown that the main disadvantage of this dual fuel combustion is its negative impact on engine efficiency compared to the normal diesel operation, while carbon monoxide emissions are also increased. The pilot diesel fuel quantity and injection advance influence significantly the combustion mechanism. Then, in order to examine the effect of these two parameters on the performance and emissions, a comprehensive two-zone phenomenological model is employed and applied on a high-speed, pilot ignited, natural gas diesel engine located at the authors' laboratory. According to the results, the simultaneously increase of the pilot fuel quantity accompanied with an increase of its injection timing results to an improvement of the engine efficiency (increase) and of the emitted CO emissions (decrease) while it has a negative effect (increase) of NO emissions

Improvement of combustion in a direct injection diesel engine by micro-hole nozzle; Micro hole nozzle wo mochiita chokusetsu funshashiki diesel kikan no nensho kaizen

Energy Technology Data Exchange (ETDEWEB)

Murata, M. [Keio University, Tokyo (Japan); Kobori, S. [Tokyo Institute of Technology, Tokyo (Japan); Iida, N. [Keio University, Tokyo (Japan). Faculty of Science and Technology

2000-07-25

In an attempt to promote the atomization of fuel spray and the mixing of fuel and air in diesel engines, a micro-hole nozzle which has orifices with a diameter smaller than 0.10mm was developed. In this study, the combustion tests were carried out using a single cylinder diesel engine equipped with a micro-hole nozzle and a common rail type high-pressure fuel injection system. A comparison with the results of a conventional nozzle experiment showed that the peak of initial premixed combustion increased, but the peak of diffusion combustion decreased. As a result, when nozzle orifice diameter become small from {phi} 0.15 mm to {phi} 0.10 mm, the combustion was accompanied by smokeless with the same levels of NO{sub x} emission and fuel economy. And results of a comparison the toroidal type chamber with the shallow dish type chamber revealed that the optimization of combustion chamber is necessary for the increase of the injection stage with increasing of the number of nozzle orifice. If an orifice diameter becomes {phi} 0.06 mm, the diffusion combustion can not be observed and the combustion is formed of only premixed combustion. The combustion in the case of {phi} 0.06 mm was accompanied with the drastic deterioration of fuel economy, smoke and HC with all over load. But the micro-hole nozzle has a potential for the formation of the lean and homogeneous premixed mixture until the fuel-air mixture ignites. (author)

NO-diagnostics in the combustion chamber of a gasoline direct-injection engine with spray-guided combustion process in a four-cylinder transparent engine; NO-Diagnostik im Brennraum eines direkteinspritzenden Ottomotors mit strahlgefuehrtem Brennverfahren an einem Vierzylinder-Transparentmotor

Energy Technology Data Exchange (ETDEWEB)

Suck, G.; Jakobs, J. [Volkswagen AG - Konzernforschung, Wolfsburg (Germany); Nicklitzsch, S. [IAV GmbH - Versuch Ottomotoren, Chemnitz (Germany); Bessler, W.G.; Hofmann, M.; Schulz, C. [PCI, Universitaet Heidelberg (Germany)

2004-07-01

For further reduction of fuel consumption in modern gasoline direct-injection engines, the Volkswagen Group Research is investigating the spray-guided combustion process. To benefit from fuel economy achieved by this combustion process in the sustained development of the Volkswagen FSI {sup registered} -technology, minimizing the engine-out NO{sub x}-emissions is necessary. In this proceeding, we report on the application of several measurement techniques, which include NO-LIF, in-cylinder gas sampling and fast CLD. The aim is the identification of major factors which effect NO-formation in a spray-guided combustion process. Double-injection during the compression stroke allows the generation of double-stratification of the air-fuel mixture cloud. A fuel-rich core with good ignition characteristics is surrounded by a fuel-lean gas mixture. These conditions show that NO-emissions can significantly be reduced while maintaining the good fuel economy. Spray-guided direct-injection allows the expansion of the operation-map area with stratified operation in comparison to recent serial production gasoline DI engines with wall-guided or air-guided combustion processes. It is, however, only possible to benefit from this advantage under realistic conditions of an operating automobile application when the engine-out NO{sub x}-flux is below a limit given by the storage capacity of the catalyst. NO{sub x} exhaust aftertreatment with storage catalysts requires regeneration cycles with fuel-air equivalent ratios {phi} > 1, which effectively increase fuel consumption. (orig.)

AN EXPERIMENTAL NOX REDUCTION POTENTIAL INVESTIGATION OF THE PARTIAL HCCI APPLICATION, ON A HIGH PRESSURE FUEL INJECTION EQUIPPED DIESEL ENGINE BY IMPLEMENTING FUMIGATION OF GASOLINE PORT INJECTION

OpenAIRE

ERGENÇ, Alp Tekin; YÜKSEK, Levent; ÖZENER, Orkun; IŞIN, Övün

2016-01-01

This work investigates the effects of partial HCCI (Homogeneous charge compression ignition) application on today's modern diesel engine tail pipe NOx emissions. Gasoline fumigation is supplied via a port fuel injection system located in the intake port of DI(Direct injection) diesel engine to maintain partial HCCI conditions and also diesel fuel injected directly into the combustion chamber before TDC(Top dead center). A single cylinder direct injection diesel research engine equipped w...

COMBUSTION HEAT RELEASE RATE ANALYSIS OF C.I. ENGINE WITH SECONDARY CO-INJECTION OF DEE-H2O SOLUTION - A VIBRATIONAL APPROACH

Directory of Open Access Journals (Sweden)

Y. V. V. SATYANARAYANA MURTHY

2015-08-01

Full Text Available This paper discusses the combustion propensity of single cylinder direct injection engine fueled with palm kernel methyl ester (PKME, which is non- edible oil and a secondary co-injection of saturated Diethyl ether (DEE with water. DEE along with water is fumigated through a high pressure nozzle fitted to the inlet manifold of the engine and the flow rate of the secondary injection was electronically controlled. DEE is known to improve the cold starting problem in engines when used in straight diesel fuel. However, its application in emulsion form is little known. Experimental results show that for 5% DEE- H2O solution injection, occurrence of maximum net heat release rate is delayed due to controlled premixed combustion, which normally helped in better torque conversion when the piston is in accelerated mode. Vibration measurements in the frequency range of 900Hz to 1300Hz revealed that a new mode of combustion has taken place with different excitation frequencies.

Effect of Fuel Injection Strategy on the Carbonaceous Structure Formation and Nanoparticle Emission in a DISI Engine Fuelled with Butanol

Directory of Open Access Journals (Sweden)

Simona Silvia Merola

2017-06-01

Full Text Available Within the context of ever wider expansion of direct injection in spark ignition engines, this investigation was aimed at improved understanding of the correlation between fuel injection strategy and emission of nanoparticles. Measurements performed on a wall guided engine allowed identifying the mechanisms involved in the formation of carbonaceous structures during combustion and their evolution in the exhaust line. In-cylinder pressure was recorded in combination with cycle-resolved flame imaging, gaseous emissions and particle size distribution. This complete characterization was performed at three injection phasing settings, with butanol and commercial gasoline. Optical accessibility from below the combustion chamber allowed visualization of diffusive flames induced by fuel deposits; these localized phenomena were correlated to observed changes in engine performance and pollutant species. With gasoline fueling, minor modifications were observed with respect to combustion parameters, when varying the start of injection. The alcohol, on the other hand, featured marked sensitivity to the fuel delivery strategy. Even though the start of injection was varied in a relatively narrow crank angle range during the intake stroke, significant differences were recorded, especially in the values of particle emissions. This was correlated to the fuel jet-wall interactions; the analysis of diffusive flames, their location and size confirmed the importance of liquid film formation in direct injection engines, especially at medium and high load.

Experimental investigation on combustion performance of cavity-strut injection of supercritical kerosene in supersonic model combustor

Science.gov (United States)

Sun, Ming-bo; Zhong, Zhan; Liang, Jian-han; Wang, Hong-bo

2016-10-01

Supersonic combustion with cavity-strut injection of supercritical kerosene in a model scramjet engine was experimentally investigated in Mach 2.92 facility with the stagnation temperatures of approximately 1430 K. Static pressure distribution in the axial direction was determined using pressure transducers installed along the centerline of the model combustor top walls. High speed imaging camera was used to capture flame luminosity and combustion region distribution. Multi-cavities were used to and stabilize the combustion in the supersonic combustor. Intrusive injection by thin struts was used to enhance the fuel-air mixing. Supercritical kerosene at temperatures of approximately 780 K and various pressures was prepared using a heat exchanger driven by the hot gas from a pre-burner and injected at equivalence ratios of approximately 1.0. In the experiments, combustor performances with different strut injection schemes were investigated and compared to direct wall injection scheme based on the measured static pressure distributions, the specific thrust increments and the images obtained by high-speed imaging camera. The experimental results showed that the injection by thin struts could obtain an enhanced mixing in the field but could not acquire a steady flame when mixing field cannot well match cavity separation region. There is no significant difference on performance between different schemes since the unsteady intermittent and oscillating flame leads to no actual combustion efficiency improvement.

Gasoline Ultra Efficient Fuel Vehicle with Advanced Low Temperature Combustion

Energy Technology Data Exchange (ETDEWEB)

Confer, Keith [Delphi Automotive Systems, LLC, Troy, MI (United States)

2014-12-18

The objective of this program was to develop, implement and demonstrate fuel consumption reduction technologies which are focused on reduction of friction and parasitic losses and on the improvement of thermal efficiency from in-cylinder combustion. The program was executed in two phases. The conclusion of each phase was marked by an on-vehicle technology demonstration. Phase I concentrated on short term goals to achieve technologies to reduce friction and parasitic losses. The duration of Phase I was approximately two years and the target fuel economy improvement over the baseline was 20% for the Phase I demonstration. Phase II was focused on the development and demonstration of a breakthrough low temperature combustion process called Gasoline Direct- Injection Compression Ignition (GDCI). The duration of Phase II was approximately four years and the targeted fuel economy improvement was 35% over the baseline for the Phase II demonstration vehicle. The targeted tailpipe emissions for this demonstration were Tier 2 Bin 2 emissions standards.

A Second Generation Swirl-Venturi Lean Direct Injection Combustion Concept

Science.gov (United States)

Tacina, Kathleen M.; Chang, Clarence T.; He, Zhuohui Joe; Lee, Phil; Dam, Bidhan; Mongia, Hukam

2014-01-01

A low-NO (sub x) aircraft gas turbine engine combustion concept was developed and tested. The concept is a second generation swirl-venturi lean direct injection (SV-LDI) concept. LDI is a lean-burn combustion concept in which the fuel is injected directly into the flame zone. Three second generation SV-LDI configurations were developed. All three were based on the baseline 9-point SV-LDI configuration reported previously. These second generation configurations had better low power operability than the baseline 9-point configuration. Two of these second generation configurations were tested in a NASA Glenn Research Center flametube; these two configurations are called the at dome and 5-recess configurations. Results show that the 5-recess configuration generally had lower NO (sub x) emissions than the flat dome configuration. Correlation equations were developed for the flat dome configuration so that the landing-takeoff NO (sub x) emissions could be estimated. The flat dome landing-takeoff NO (sub x) is estimated to be 87-88 percent below the CAEP/6 standards, exceeding the ERA project goal of 75 percent reduction.

Mixing enhancement in a scramjet combustor using fuel jet injection swirl

Science.gov (United States)

Flesberg, Sonja M.

The scramjet engine has proven to be a viable means of powering a hypersonic vehicle, especially after successful flights of the X-51 WaveRider and various Hy-SHOT test vehicles. The major challenge associated with operating a scramjet engine is the short residence time of the fuel and oxidizer in the combustor. The fuel and oxidizer have only milliseconds to mix, ignite and combust in the combustion chamber. Combustion cannot occur until the fuel and oxidizer are mixed on a molecular level. Therefore the improvement of mixing is of utmost interest since this can increase combustion efficiency. This study investigated mixing enhancement of fuel and oxidizer within the combustion chamber of a scramjet by introducing swirl to the fuel jet. The investigation was accomplished with numerical simulations using STAR-CCM+ computational fluid dynamic software. The geometry of the University of Virginia Supersonic Combustion Facility was used to model the isolator, combustor and nozzle of a scramjet engine for simulation purposes. Experimental data from previous research at the facility was used to verify the simulation model before investigating the effect of fuel jet swirl on mixing. The model used coaxial fuel jet with a swirling annular jet. Single coaxial fuel jet and dual coaxial fuel jet configurations were simulated for the investigation. The coaxial fuel jets were modelled with a swirling annular jet and non-swirling core jet. Numerical analysis showed that fuel jet swirl not only increased mixing and entrainment of the fuel with the oxidizer but the mixing occurred further upstream than without fuel jet swirl. The burning efficiency was calculated for the all the configurations. An increase in burning efficiency indicated an increase in the mixing of H2 with O2. In the case of the single fuel jet models, the maximum burning efficiency increase due to fuel injection jet swirl was 23.3%. The research also investigated the possibility that interaction between two

Chemistry and radiation in oxy-fuel combustion

DEFF Research Database (Denmark)

Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

2011-01-01

In order to investigate the role of combustion chemistry and radiation heat transfer in oxy-fuel combustion modeling, a computational fluid dynamics (CFD) modeling study has been performed for two different oxy-fuel furnaces. One is a lab-scale 0.8MW oxy-natural gas flame furnace whose detailed in....... Among the key issues in combustion modeling, e.g., mixing, radiation and chemistry, this paper derives useful guidelines on radiation and chemistry implementation for reliable CFD analyses of oxy-fuel combustion, particularly for industrial applications....

Modeling of large-scale oxy-fuel combustion processes

DEFF Research Database (Denmark)

Yin, Chungen

2012-01-01

Quite some studies have been conducted in order to implement oxy-fuel combustion with flue gas recycle in conventional utility boilers as an effective effort of carbon capture and storage. However, combustion under oxy-fuel conditions is significantly different from conventional air-fuel firing......, among which radiative heat transfer under oxy-fuel conditions is one of the fundamental issues. This paper demonstrates the nongray-gas effects in modeling of large-scale oxy-fuel combustion processes. Oxy-fuel combustion of natural gas in a 609MW utility boiler is numerically studied, in which...... calculation of the oxy-fuel WSGGM remarkably over-predicts the radiative heat transfer to the furnace walls and under-predicts the gas temperature at the furnace exit plane, which also result in a higher incomplete combustion in the gray calculation. Moreover, the gray and non-gray calculations of the same...

Preliminary study on the combustion and emission in a direct injection LPG spark ignition engine

Energy Technology Data Exchange (ETDEWEB)

Oh, Seungmook; Lee, Seokhwan [Korea Institute of Machinery and Materials (Korea, Republic of)

2010-07-01

In the energy sector, with the implementation of stringent regulations on combustion emissions and the depletion of conventional fuels, there is an important need for low carbon fuel and advanced engine technology. Korea is the country with the most LPG vehicles in the world and the aim of this study, performed by the Korea Institute of Machinery and Materials, is to compare the performance of LPG direct injection spark ignition (DISI) with gasoline DISI. Heat release analyses were conducted to determine the combustion characteristics of both systems and experiments were performed to determine gaseous and nanoparticle emissions. Results showed that LPG provides a better thermal efficiency than gasoline and that THC, NOx, and particulate emissions were lower for LPG than for gasoline. This study demonstrated that LPG DISI can provide better combustion efficiency and lower emissions than gasoline DISI.

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.

Experimental studies on the combustion characteristics and performance of a direct injection engine fueled with biodiesel/diesel blends

International Nuclear Information System (INIS)

Qi, D.H.; Chen, H.; Geng, L.M.; Bian, Y. ZH.

2010-01-01

Biodiesel is an alternative diesel fuel that can be produced from different kinds of vegetable oils. It is an oxygenated, non-toxic, sulphur-free, biodegradable, and renewable fuel and can be used in diesel engines without significant modification. However, the performance, emissions and combustion characteristics will be different for the same biodiesel used in different types of engine. In this study, the biodiesel produced from soybean crude oil was prepared by a method of alkaline-catalyzed transesterification. The effects of biodiesel addition to diesel fuel on the performance, emissions and combustion characteristics of a naturally aspirated DI compression ignition engine were examined. Biodiesel has different properties from diesel fuel. A minor increase in brake specific fuel consumption (BSFC) and decrease in brake thermal efficiency (BTE) for biodiesel and its blends were observed compared with diesel fuel. The significant improvement in reduction of carbon monoxide (CO) and smoke were found for biodiesel and its blends at high engine loads. Hydrocarbon (HC) had no evident variation for all tested fuels. Nitrogen oxides (NOx) were slightly higher for biodiesel and its blends. Biodiesel and its blends exhibited similar combustion stages to diesel fuel. The use of transesterified soybean crude oil can be partially substituted for the diesel fuel at most operating conditions in terms of the performance parameters and emissions without any engine modification.

Fuel Combustion and Engine Performance | Transportation Research | NREL

Science.gov (United States)

Fuel Combustion and Engine Performance Fuel Combustion and Engine Performance Photo of a gasoline emissions in advanced engine technologies. Photo by Dennis Schroeder, NREL NREL's combustion research and combustion and engine research activities include: Developing experimental and simulation research platforms

IN-SITU Optical Diagnostics Of Diesel Spray Injection And Combustion For Engine-Like Conditions

Energy Technology Data Exchange (ETDEWEB)

Bougie, B.; Tulej, M.; Dreier, T.; Gerber, T.

2004-03-01

A combination of shadowgraphy, laser elastic scattering, laser-induced incandescence and chemiluminescence imaging was conducted to characterize the propagation, vaporization and soot formation due to combustion of Diesel fuel injection into a hot (550-850 K), high pressure (4-6 MPa) gaseous environment as provided by the PSI high temperature pressure vessel (HTDZ). (author)

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...

Combustion of fuels with low sintering temperature

Energy Technology Data Exchange (ETDEWEB)

Dalin, D

1950-08-16

A furnace for the combustion of low sintering temperature fuel consists of a vertical fuel shaft arranged to be charged from above and supplied with combustion air from below and containing a system of tube coils extending through the fuel bed and serving the circulation of a heat-absorbing fluid, such as water or steam. The tube-coil system has portions of different heat-absorbing capacity which are so related to the intensity of combustion in the zones of the fuel shaft in which they are located as to keep all parts of the fuel charge below sintering temperature.

Experimental Studies of Diestrol-Micro Emulsion Fuel in a Direct Injection Compression Ignition Engine under Varying Injection Pressures and Timings

Science.gov (United States)

Kannan, Gopal Radhakrishnan

2018-02-01

The research work on biodiesel becomes more attractive in the context of limited availability of petroleum fuels and rapid increase of harmful emissions from diesel engine using conventional fossil fuels. The present investigation has dealt with the influence of biodiesel-diesel-ethanol (diestrol) water micro emulsion fuel (B60D20E20M) on the performance, emission and combustion characteristics of a diesel engine under different injection pressure and timing. The results revealed that the maximum brake thermal efficiency of 32.4% was observed at an injection pressure of 260 bar and injection timing of 25.5°bTDC. In comparison with diesel, micro emulsion fuel showed reduction in carbon monoxide (CO) and total hydrocarbon (THC) by 40 and 24%, respectively. Further, micro emulsion fuel decreased nitric oxide (NO) emission and smoke emission by 7 and 20.7%, while the carbon dioxide (CO2) emission is similar to that of diesel.

Fuel spray and combustion characteristics of butanol blends in a constant volume combustion chamber

International Nuclear Information System (INIS)

Liu, Yu; Li, Jun; Jin, Chao

2015-01-01

Highlights: • A sudden drop is observed in spray penetration for B10S10D80 fuel at 800 and 900 K. • With increasing of temperature, auto-ignition timings of fuels become unperceivable. • Low n-butanol addition has little effect on autoignition timings from 800 to 1200 K. • n-Butanol additive can reduce soot emissions at the near-wall regions. • Larger soot reduction is seen at higher ambient temperatures for n-butanol addition. - Abstract: The processes of spray penetrations, flame propagation and soot formation and oxidation fueling n-butanol/biodiesel/diesel blends were experimentally investigated in a constant volume combustion chamber with an optical access. B0S20D80 (0% n-butanol, 20% soybean biodiesel, and 80% diesel in volume) was prepared as the base fuel. n-Butanol was added into the base fuel by volumetric percent of 5% and 10%, denoted as B5S15D80 (5% n-butanol/15% soybean biodiesel/80% diesel) and B10S10D80 (10% n-butanol/10% soybean biodiesel/80% diesel). The ambient temperatures at the time of fuel injection were set to 800 K, 900 K, 1000 K, and 1200 K. Results indicate that the penetration length reduces with the increase of n-butanol volumes in blending fuels and ambient temperatures. The spray penetration presents a sudden drop as fueling B10S10D80 at 800 K and 900 K, which might be caused by micro-explosion. A larger premixed combustion process is observed at low ambient temperatures, while the heat release rate of high ambient temperatures presents mixing controlled diffusion combustion. With a lower ambient temperature, the auto-ignition delay becomes longer with increasing of n-butanol volume in blends. However, with increasing of ambient temperatures, the auto-ignition timing between three fuels becomes unperceivable. Generally, low n-butanol addition has a limited or no effect on the auto-ignition timing in the current conditions. Compared with the base fuel of B0S20D80, n-butanol additive with 5% or 10% in volume can reduce soot

Formation of fuel NOx during black-liquor combustion

International Nuclear Information System (INIS)

Nichols, K.M.; Lien, S.J.

1993-01-01

Fuel NOx and thermal NOx were measured in combustion gases from black liquors in two laboratory furnaces. Combustion at 950 C in air (8% O 2 ) produced NOx concentrations of 40-80ppm. Combustion at 950 C in synthetic air containing no nitrogen (21% 0 2 in Ar) produced the same result, demonstrating that all of the NOx produced during combustion at 950 C was fuel NOx. Formation of fuel NOx increased moderately with increasing temperature in the range of 800-1,000 C, but temperature sensitivity of fuel NOx was much less than that of thermal NOx. The results imply that the major source of NOx in recovery furnace emissions is the fuel NOx in recovery furnace formed by conversion of liquor-bound nitrogen during combustion. This is consistent with thermal NOx theory, which postulates that black-liquor combustion temperatures are too low to generate significant amounts of thermal NOx

Optimization of the combustion system of a medium duty direct injection diesel engine by combining CFD modeling with experimental validation

International Nuclear Information System (INIS)

Benajes, Jesus; Novella, Ricardo; Pastor, Jose Manuel; Hernández-López, Alberto; Hasegawa, Manabu; Tsuji, Naohide; Emi, Masahiko; Uehara, Isshoh; Martorell, Jordi; Alonso, Marcos

2016-01-01

Highlights: • A DOE-based optimization of the combustion system of a CI engine has been performed. • Improving efficiency controlling emissions needs optimizing bowl design and settings. • Swirl-supported with re-entrant bowl combustion system is required after optimizing. • Computationally optimized combustion system has been validated by engine tests. - Abstract: The research in the field of internal combustion engines is currently driven by the needs of decreasing fuel consumption and CO_2 emissions, while fulfilling the increasingly stringent pollutant emissions regulations. In this framework, this research work focuses on describing a methodology for optimizing the combustion system of Compression Ignition (CI) engines, by combining Computational Fluid Dynamics (CFD) modeling, and the statistical Design of Experiments (DOE) technique known as Response Surface Method (RSM). As a key aspect, in addition to the definition of the optimum set of values for the input parameters, this methodology is extremely useful to gain knowledge on the cause/effect relationships between the input and output parameters under investigation. This methodology is applied in two sequential studies to the optimization of the combustion system of a 4-cylinder 4-stroke Medium Duty Direct Injection (DI) CI engine, minimizing the fuel consumption while fulfilling the emission limits in terms of NO_x and soot. The first study targeted four optimization parameters related to the engine hardware including piston bowl geometry, injector nozzle configuration and mean swirl number (MSN) induced by the intake manifold design. After the analysis of the results, the second study extended to six parameters, limiting the optimization of the engine hardware to the bowl geometry, but including the key air management and injection settings. For both studies, the simulation plans were defined following a Central Composite Design (CCD), providing 25 and 77 simulations respectively. The results

Fuel and Additive Characterization for HCCI Combustion

International Nuclear Information System (INIS)

Aceves, S M; Flowers, D; Martinez-Frias, J; Espinosa-Loza, F; Pitz, W J; Dibble, R

2003-01-01

This paper shows a numerical evaluation of fuels and additives for HCCl combustion. First, a long list of candidate HCCl fuels is selected. For all the fuels in the list, operating conditions (compression ratio, equivalence ratio and intake temperature) are determined that result in optimum performance under typical operation for a heavy-duty engine. Fuels are also characterized by presenting Log(p)-Log(T) maps for multiple fuels under HCCl conditions. Log(p)-Log(T) maps illustrate important processes during HCCl engine operation, including compression, low temperature heat release and ignition. Log(p)-Log(T) diagrams can be used for visualizing these processes and can be used as a tool for detailed analysis of HCCl combustion. The paper also includes a ranking of many potential additives. Experiments and analyses have indicated that small amounts (a few parts per million) of secondary fuels (additives) may considerably affect HCCl combustion and may play a significant role in controlling HCCl combustion. Additives are ranked according to their capability to advance HCCl ignition. The best additives are listed and an explanation of their effect on HCCl combustion is included

Oxy-fuel combustion with integrated pollution control

Science.gov (United States)

Patrick, Brian R [Chicago, IL; Ochs, Thomas Lilburn [Albany, OR; Summers, Cathy Ann [Albany, OR; Oryshchyn, Danylo B [Philomath, OR; Turner, Paul Chandler [Independence, OR

2012-01-03

An oxygen fueled integrated pollutant removal and combustion system includes a combustion system and an integrated pollutant removal system. The combustion system includes a furnace having at least one burner that is configured to substantially prevent the introduction of air. An oxygen supply supplies oxygen at a predetermine purity greater than 21 percent and a carbon based fuel supply supplies a carbon based fuel. Oxygen and fuel are fed into the furnace in controlled proportion to each other and combustion is controlled to produce a flame temperature in excess of 3000 degrees F. and a flue gas stream containing CO2 and other gases. The flue gas stream is substantially void of non-fuel borne nitrogen containing combustion produced gaseous compounds. The integrated pollutant removal system includes at least one direct contact heat exchanger for bringing the flue gas into intimated contact with a cooling liquid to produce a pollutant-laden liquid stream and a stripped flue gas stream and at least one compressor for receiving and compressing the stripped flue gas stream.

Coal char combustion under a CO{sub 2}-rich atmosphere: Implications for pulverized coal injection in a blast furnace

Energy Technology Data Exchange (ETDEWEB)

Borrego, A.G.; Casal, M.D. [Instituto Nacional del Carbon, CSIC. P.O. Box 73, 33080 Oviedo (Spain); Osorio, E.; Vilela, A.C.F. [Laboratorio de Siderurgia, DEMET/PPGEM - Universidade Federal do Rio Grande do Sul. P.O. Box 15021, 91501-970 Porto Alegre (Brazil)

2008-11-15

Pulverized coal injection (PCI) is employed in blast furnace tuyeres attempting to maximize the injection rate without increasing the amount of unburned char inside the stack of the blast furnace. When coal is injected with air through the injection lance, the resolidified char will burn in an atmosphere with a progressively lower oxygen content and higher CO{sub 2} concentration. In this study an experimental approach was followed to separate the combustion process into two distinct devolatilization and combustion steps. Initially coal was injected into a drop tube furnace (DTF) operating at 1300 C in an atmosphere with a low oxygen concentration to ensure the combustion of volatiles and prevent the formation of soot. Then the char was refired into the DTF at the same temperature under two different atmospheres O{sub 2}/N{sub 2} (typical combustion) and O{sub 2}/CO{sub 2} (oxy-combustion) with the same oxygen concentration. Coal injection was also performed under a higher oxygen concentration in atmospheres typical for both combustion and oxy-combustion. The fuels tested comprised a petroleum coke and coals currently used for PCI injection ranging from high volatile to low volatile bituminous rank. Thermogravimetric analyses and microscopy techniques were used to establish the reactivity and appearance of the chars. Overall similar burnouts were achieved with N{sub 2} and CO{sub 2} for similar oxygen concentrations and therefore no loss in burnout should be expected as a result of enrichment in CO{sub 2} in the blast furnace gas. The advantage of increasing the amount of oxygen in a reacting atmosphere during burnout was found to be greater, the higher the rank of the coal. (author)

Co-combustion of Fossil Fuels and Waste

DEFF Research Database (Denmark)

Wu, Hao

The Ph.D. thesis deals with the alternative and high efficiency methods of using waste-derived fuels in heat and power production. The focus is on the following subjects: 1) co-combustion of coal and solid recovered fuel (SRF) under pulverized fuel combustion conditions; 2) dust-firing of straw...

Low-Emission combustion of fuel in aeroderivative gas turbines

Science.gov (United States)

Bulysova, L. A.; Vasil'ev, V. D.; Berne, A. L.

2017-12-01

The paper is the first of a planned set of papers devoted to the world experience in development of Low Emission combustors (LEC) for industrial Gas Turbines (GT). The purpose of the article is to summarize and analyze the most successful experience of introducing the principles of low-emission combustion of the so-called "poor" (low fuel concentration in air when the excess air ratio is about 1.9-2.1) well mixed fuelair mixtures in the LEC for GTs and ways to reduce the instability of combustion. The consideration examples are the most successful and widely used aero-derivative GT. The GT development meets problems related to the difference in requirements and operation conditions between the aero, industrial, and power production GT. One of the main problems to be solved is the LEC development to mitigate emissions of the harmful products first of all the Nitrogen oxides NOx. The ways to modify or convert the initial combustors to the LEC are shown. This development may follow location of multiburner mixers within the initial axial envelope dimensions or conversion of circular combustor to the can type one. The most interesting are Natural Gas firing GT without water injection into the operating process or Dry Low emission (DLE) combustors. The current GT efficiency requirement may be satisfied at compressor exit pressure above 3 MPa and Turbine Entry temperature (TET) above 1500°C. The paper describes LEC examples based on the concept of preliminary prepared air-fuel mixtures' combustion. Each combustor employs its own fuel supply control concept based on the fuel flow-power output relation. In the case of multiburner combustors, the burners are started subsequently under a specific scheme. The can type combustors have combustion zones gradually ignited following the GT power change. The combustion noise problem experienced in lean mixtures' combustion is also considered, and the problem solutions are described. The GT test results show wide ranges of stable

Combustion characteristics of the LO2/GCH4 fuel-rich preburners for staged combustion cycle rocket engines

Science.gov (United States)

Ono, Fumiei; Tamura, Hiroshi; Sakamoto, Hiroshi; Sasaki, Masaki

1991-09-01

The combustion characteristics of Liquid Oxygen (LO2)/Gaseous Methane (GCH4) fuel rich preburners were experimentally studied using subscale hardware. Three types of preburners with coaxial type propellant injection elements were designed and fabricated, and were used for hot fire testing. LO2 was used as oxidizer, and GCH4 at room temperature was used as fuel. The tests were conducted at chamber pressures ranging from 6.7 to 11.9 M Pa, and oxidizer to fuel ratios ranged from 0.16 to 0.42. The test results, which include combustion gas temperature T(sub c), characteristic velocity C(sup *) and soot adhesion data, are presented. The T(sub c) efficiency and the C(sup *) efficiency were found to be a function of oxidizer to fuel ratio and chamber pressure. These efficiencies are correlated by an empirical correlation parameter which accounts for the effects of oxidizer to fuel ratio and chamber pressure. The exhaust plumes were colorless and transparent under all tests conditions. There was some soot adhesion to the chamber wall, but no soot adhesion was observed on the main injector simulator orifices. Higher temperature igniter gas was required to ignite the main propellants of the preburner compared with that of the LO2/Gaseous Hydrogen (GH2) propellants combination.

Application of macro-cellular SiC reactor to diesel engine-like injection and combustion conditions

Science.gov (United States)

Cypris, Weclas, M.; Greil, P.; Schlier, L. M.; Travitzky, N.; Zhang, W.

2012-05-01

One of novel combustion technologies for low emissions and highly efficient internal combustion engines is combustion in porous reactors (PM). The heat release process inside combustion reactor is homogeneous and flameless resulting in a nearly zero emissions level. Such combustion process, however is non-stationary, is performed under high pressure with requirement of mixture formation directly inside the combustion reactor (high pressure fuel injection). Reactor heat capacity resulting in lowering of combustion temperature as well as internal heat recuperation during the engine cycle changes the thermodynamic conditions of the process as compared to conventional engine. For the present investigations a macro-cellular lattice structure based on silicon carbide (non-foam structure) with 600 vertical cylindrical struts was fabricated and applied to engine-like combustion conditions (combustion chamber). The lattice design with a high porosity > 80% was shaped by indirect three-dimensional printing of a SiC powder mixed with a dextrin binder which also serves as a carbon precursor. In order to perform detailed investigations on low-and high-temperature oxidation processes in porous reactors under engine-like conditions, a special combustion chamber has been built and equipped with a Diesel common-rail injection system. This system simulates the thermodynamic conditions at the time instance of injection onset (corresponding to the nearly TDC of compression in a real engine). Overall analysis of oxidation processes (for variable initial pressure, temperature and air excess ratio) for free Diesel spray combustion and for combustion in porous reactor allows selection of three regions representing different characteristics of the oxidation process represented by a single-step and multi-step reactions Another characteristic feature of investigated processes is reaction delay time. There are five characteristic regions to be selected according to the delay time (t) duration

Combustion characteristics and air pollutant formation during oxy-fuel co-combustion of microalgae and lignite.

Science.gov (United States)

Gao, Yuan; Tahmasebi, Arash; Dou, Jinxiao; Yu, Jianglong

2016-05-01

Oxy-fuel combustion of solid fuels is seen as one of the key technologies for carbon capture to reduce greenhouse gas emissions. The combustion characteristics of lignite coal, Chlorella vulgaris microalgae, and their blends under O2/N2 and O2/CO2 conditions were studied using a Thermogravimetric Analyzer-Mass Spectroscopy (TG-MS). During co-combustion of blends, three distinct peaks were observed and were attributed to C. vulgaris volatiles combustion, combustion of lignite, and combustion of microalgae char. Activation energy during combustion was calculated using iso-conventional method. Increasing the microalgae content in the blend resulted in an increase in activation energy for the blends combustion. The emissions of S- and N-species during blend fuel combustion were also investigated. The addition of microalgae to lignite during air combustion resulted in lower CO2, CO, and NO2 yields but enhanced NO, COS, and SO2 formation. During oxy-fuel co-combustion, the addition of microalgae to lignite enhanced the formation of gaseous species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multi-zone modeling of combustion and emissions formation in DI diesel engine operating on ethanol-diesel fuel blends

International Nuclear Information System (INIS)

Rakopoulos, C.D.; Antonopoulos, K.A.; Rakopoulos, D.C.; Hountalas, D.T.

2008-01-01

A multi-zone model for calculation of the closed cycle of a direct injection (DI) diesel engine is applied for the interesting case of its operation with ethanol-diesel fuel blends, the ethanol (bio-fuel) being considered recently as a promising extender to petroleum distillates. Although there are many experimental studies, there is an apparent scarcity of theoretical models scrutinizing the formation mechanisms of combustion generated emissions when using bio-fuels. This is a two dimensional, multi-zone model with the issuing fuel jets divided into several discrete volumes, called 'zones', formed along and across the direction of the fuel injection. The model follows each zone, with its own time history, as the spray penetrates into the swirling air environment of the combustion chamber. Droplet evaporation and jet mixing models are used to determine the amount of fuel and entrained air in each zone available for combustion. The mass, energy and state equations are applied in each zone to provide local temperatures and cylinder pressure histories. The concentrations of the various constituents are calculated by adopting a chemical equilibrium scheme for the C-H-O-N system of eleven species considered, together with chemical rate equations for calculation of nitric oxide (NO) and a model for net soot formation. The results from the computer program, implementing the analysis, for the in cylinder pressure, exhaust NO concentration and soot density compare well with the corresponding measurements from an experimental investigation conducted on a fully automated test bed, standard 'Hydra', DI diesel engine located at the authors' laboratory, which is operated with ethanol-diesel fuel blends containing 5%, 10% and 15% (by vol.) ethanol. Iso-contour plots of equivalence ratio, temperature, NO and soot inside the cylinder at various instants of time, when using these ethanol-diesel fuel blends against the diesel fuel (baseline fuel), shed light on the mechanisms

Lube-oil dilution of gasoline direct-injection engines with ethanol fuels; Schmieroelverduennung von direkteinspritzenden Ottomotoren unter Kaltstartrandbedingungen

Energy Technology Data Exchange (ETDEWEB)

Kuepper, Carsten; Pischinger, Stefan [RWTH Aachen Univ. (Germany). Lehrstuhl fuer Verbrennungskraftmaschinen (VKA); Artmann, Chrsitina; Rabl, Hans-Peter [Hochschule Regensburg (Germany). Labor fuer Verbrennungsmotoren und Abgasnachbehandlung

2013-09-15

Ethanol fuel mixtures account for the majority of biofuels used worldwide. However, their properties make these fuels more difficult to use in cold conditions and especially when starting a cold engine. As part of the FVV research project 'Lubricant Dilution with Ethanol Fuels under Cold Start Conditions', the Institute for Combustion Engines (VKA) at RWTH Aachen University and the Combustion Engines and Emission Control Laboratory at Regensburg University of Applied Sciences have investigated the influence of the ethanol content in fuels on the dilution of the lubricating oil in modern direct-injection gasoline engines. (orig.)

Combustion and emissions control in diesel-methane dual fuel engines: The effects of methane supply method combined with variable in-cylinder charge bulk motion

International Nuclear Information System (INIS)

Carlucci, Antonio P.; Laforgia, Domenico; Saracino, Roberto; Toto, Giuseppe

2011-01-01

Highlights: → We studied dual fuel combustion in diesel engines. → Bulk flow structure of in-cylinder charge and methane supply method were investigated. → Swirl charge motion is capable to enhance air-methane mixture oxidation at low loads. → Methane port injection is capable to reduce unburned hydrocarbons and nitric oxides. - Abstract: In this paper, the results of an extensive experimental campaign about dual fuel combustion development and the related pollutant emissions are reported, paying particular attention to the effect of both the in-cylinder charge bulk motion and methane supply method. A diesel common rail research engine was converted to operate in dual fuel mode and, by activating/deactivating the two different inlet valves of the engine (i.e. swirl and tumble), three different bulk flow structures of the charge were induced inside the cylinder. A methane port injection method was proposed, in which the gaseous fuel was injected into the inlet duct very close to the intake valves, in order to obtain a stratified-like air-fuel mixture up to the end of the compression stroke. For comparison purposes, a homogeneous-like air-fuel mixture was obtained injecting methane more upstream the intake line. Combining the different positions of the methane injector and the three possible bulk flow structures, seven different engine inlet setup were tested. In this way, it was possible to evaluate the effects on dual fuel combustion due to the interaction between methane injector position and charge bulk motion. In addition, methane injection pressure and diesel pilot injection parameters were varied setting the engine at two operating conditions. For some interesting low load tests, the combustion development was studied more in detail by means of direct observation of the process, using an in-cylinder endoscope and a digital CCD camera. Each combustion image was post-processed by a dedicated software, in order to extract only those portions with flame

The effect of injection timing on energy and exergy analysis of a diesel engine with biodiesel fuel

Directory of Open Access Journals (Sweden)

A Farhadi

2017-05-01

with the experimental data shows that there was a good agreement between the model and experimental results. The results showed that advancing fuel injection timing increases the peak cylinder pressure. When fuel injecting occurs before the standard injection timing, the pressure and temperature of the charged air in the cylinder is less than that of the fuel when it is injected at standard injection timing. Thus, ignition delay of the injected fuel extends further. As a consequence, the reaction between fuel and air improves, which prepares a good mixture for burning. When the combustion starts, the rate of heat release increases in the premixed or rapid combustion phase of the combustion process due to the suitability of the mixture of air and fuel and hence the peak pressure of cylinder increases. When the injection timing is retarded, the fuel is injected into charged air that has a high temperature and pressure. Thus, in the injection timing of 10 degrees before top dead center, the maximum of incylinder pressure and temperature are reduced compared to the standard injection timing. By retarding the fuel injection into the cylinder, the indicator availability, the heat loss availability by heat transfer from cylinder walls and irreversibility are increased and by advancing the fuel injection into the cylinder, the indicator availability, the heat loss availability by heat transfer from the cylinder walls and irreversibility are reduced. High temperature will increase the produced entropy, so by advancing the injection timing the produced entropy will increase while the retarding injection timing reduces the produced entropy. Exergy and energy efficiencies increased by advancing the injection timing. At 2000 rpm the total availability and heat loss availability by heat transfer was increased compared to 1200 and 1600 rpm. Conclusions The proposed model was able to predict the pressure and temperature of the cylinder at different injection timings. By advancing the

Oxy-fuel combustion of pulverized fuels

DEFF Research Database (Denmark)

Yin, Chungen; Yan, Jinyue

2016-01-01

Oxy-fuel combustion of pulverized fuels (PF), as a promising technology for CO2 capture from power plants, has gained a lot of concerns and also advanced considerable research, development and demonstration in the last past years worldwide. The use of CO2 or the mixture of CO2 and H2O vapor as th...

Fuel and combustion stratification study of Partially Premixed Combustion

NARCIS (Netherlands)

Izadi Najafabadi, M.; Dam, N.; Somers, B.; Johansson, B.

2016-01-01

Relatively high levels of stratification is one of the main advantages of Partially Premixed Combustion (PPC) over the Homogeneous Charge Compression Ignition (HCCI) concept. Fuel stratification smoothens heat release and improves controllability of this kind of combustion. However, the lack of a

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...

Influence of injection timing on the exhaust emissions of a dual-fuel CI engine

Energy Technology Data Exchange (ETDEWEB)

Sayin, Cenk [Department of Mechanical Education, Marmara University, 34722 Istanbul (Turkey); Uslu, Kadir [Department of Automotive Education, Fatih Vocational High School, 54100 Sakarya (Turkey); Canakci, Mustafa [Department of Mechanical Education, Kocaeli University, 41380 Kocaeli (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Kocaeli (Turkey)

2008-06-15

Environmental concerns and limited amount of petroleum fuels have caused interests in the development of alternative fuels for internal combustion (IC) engines. As an alternative, biodegradable, and renewable fuel, ethanol is receiving increasing attention. Therefore, in this study, influence of injection timing on the exhaust emission of a single cylinder, four stroke, direct injection, naturally aspirated diesel engine has been experimentally investigated using ethanol blended diesel fuel from 0% to 15% with an increment of 5%. The engine has an original injection timing 27 CA BTDC. The tests were performed at five different injection timings (21 , 24 , 27 , 30 , and 33 CA BTDC) by changing the thickness of advance shim. The experimental test results showed that NO{sub x} and CO{sub 2} emissions increased as CO and HC emissions decreased with increasing amount of ethanol in the fuel mixture. When compared to the results of original injection timing, at the retarded injection timings (21 and 24 CA BTDC), NO{sub x} and CO{sub 2} emissions increased, and unburned HC and CO emissions decreased for all test conditions. On the other hand, with the advanced injection timings (30 and 33 CA BTDC), HC and CO emissions diminished, and NO{sub x} and CO{sub 2} emissions boosted for all test conditions. (author)

Effects of pilot injection timing and EGR on a modern V6 common rail direct injection diesel engine

Science.gov (United States)

Rosli Abdullah, Nik; Mamat, Rizalman; Wyszynski, Miroslaw L.; Tsolakis, Anthanasios; Xu, Hongming

2013-12-01

Nitric oxide and smoke emissions in diesel engine can be controlled by optimising the air/fuel mixture. Early injection produces premixed charge resulted in simultaneous NOx and smoke emissions reduction. However, there could be an increase in hydrocarbons and CO emissions due to fuel impinged to the cylinder wall. The focus of the present work is to investigate the effects of a variation of pilot injection timing with EGR to NOx and smoke level on a modern V6 common rail direct injection. This study is carried out at two different engine load conditions of 30 Nm and 55 Nm, at constant engine speed of 2000 rpm. The results show that the early pilot injection timing contributed to the lower smoke level and higher NOx emissions. The higher level of NOx is due to higher combustion temperatures resulting from the complete combustion. Meanwhile, the lower smoke level is due to complete fuel combustion and soot oxidation. The early pilot injection timing produces an intermediate main ignition delay which also contributed to complete combustion. The formation of smoke is higher at a high engine load compared with low engine load due to the higher amount of fuel being injected.

Prediction of air-fuel and oxy-fuel combustion through a generic gas radiation property model

International Nuclear Information System (INIS)

Yin, Chungen

2017-01-01

Highlights: • A gas radiation model for general combustion CFD presented, programmed & verified. • Its general applicability/practical accuracy demonstrated in air-fuel and oxy-fuel. • Useful guidelines for air-fuel and oxy-fuel combustion CFD suggested. • Important to include the impact of CO in gas radiation for oxy-fuel combustion CFD. - Abstract: Thermal radiation plays an important role in heat transfer in combustion furnaces. The weighted-sum-of-gray-gases model (WSGGM), representing a good compromise between computational efficiency and accuracy, is commonly used in computational fluid dynamics (CFD) modeling of combustion processes for evaluating gaseous radiative properties. However, the WSGGMs still have some limitations in practical use, e.g., unable to naturally accommodate different combustion environments, difficult to accurately address the variations in species concentrations in a flame, and inconvenient to account for the impacts of participating species other than H_2O and CO_2. As a result, WSGGMs with different coefficients have been published for specific applications. In this paper, a reliable generic model for gaseous radiation property calculation, which is a computationally efficient exponential wide band model (E-EWBM) applicable to combustion CFD and able to naturally solve all the practical limitations of the WSGGMs, is presented, programmed and verified. The model is then implemented to CFD simulation of a 300 kW air-fuel and a 0.8 MW oxy-fuel combustion furnace, respectively, to demonstrate its computational applicability to general combustion CFD and its capability in producing reliable CFD results for different combustion environments. It is found that the usefulness of the WSGGMs in oxy-fuel combustion CFD is compromised if the important impacts of high levels of CO under oxy-fuel combustion cannot be accounted for. The E-EWBM that appropriately takes the impacts of H_2O, CO_2, CO and CH_4 into account is a good replacement

Demonstration project: Oxy-fuel combustion at Callide-A plant

Energy Technology Data Exchange (ETDEWEB)

Makino, Keiji; Misawa, Nobuhiro; Kiga, Takashi; Spero, Chris

2007-07-01

Oxy-fuel combustion is expected to be one of the promising systems on CO2 recovery from pulverized-coal power plant, and enable the CO2 to be captured in a more cost-effective manner compared to other CO2 recover process. An Australia-Japan consortium was established in 2004 specifically for the purpose of conducting a feasibility study on the application of oxy-fuel combustion to an existing pulverized-coal power plant that is Callide-A power plant No.4 unit at 30MWe owned by CS Energy in Australia. One of the important components in this study has been the recent comparative testing of three Australian coals under both oxy-fuel and air combustion conditions using the IHI combustion test facilities. The tests have yielded a number of important outcomes including a good comparison of normal air with oxy-fuel combustion, significant reduction in NOx mass emission rates under oxy-fuel combustion. On the basis of the feasibility study, the project under Australia-Japan consortium is now under way for applying oxy-fuel combustion to an existing plant by way of demonstration. In this project, a demonstration plant of oxy-fuel combustion will be completed by the end of 2008. This project aims at recovering CO2 from an actual power plant for storage. (auth)

Effects of Mixture Stratification on Combustion and Emissions of Boosted Controlled Auto-Ignition Engines

Directory of Open Access Journals (Sweden)

Jacek Hunicz

2017-12-01

Full Text Available The stratification of in-cylinder mixtures appears to be an effective method for managing the combustion process in controlled auto-ignition (CAI engines. Stratification can be achieved and controlled using various injection strategies such as split fuel injection and the introduction of a portion of fuel directly before the start of combustion. This study investigates the effect of injection timing and the amount of fuel injected for stratification on the combustion and emissions in CAI engine. The experimental research was performed on a single cylinder engine with direct gasoline injection. CAI combustion was achieved using negative valve overlap and exhaust gas trapping. The experiments were performed at constant engine fueling. Intake boost was applied to control the excess air ratio. The results show that the application of the late injection strategy has a significant effect on the heat release process. In general, the later the injection is and the more fuel is injected for stratification, the earlier the auto-ignition occurs. However, the experimental findings reveal that the effect of stratification on combustion duration is much more complex. Changes in combustion are reflected in NOX emissions. The attainable level of stratification is limited by the excessive emission of unburned hydrocarbons, CO and soot.

Fuel injection assembly for use in turbine engines and method of assembling same

Science.gov (United States)

Berry, Jonathan Dwight; Johnson, Thomas Edward; York, William David; Uhm, Jong Ho

2015-12-15

A fuel injection assembly for use in a turbine engine is provided. The fuel injection assembly includes an end cover, an endcap assembly, a fluid supply chamber, and a plurality of tube assemblies positioned at the endcap assembly. Each of the tube assemblies includes housing having a fuel plenum and a cooling fluid plenum. The cooling fluid plenum is positioned downstream from the fuel plenum and separated from the fuel plenum by an intermediate wall. The plurality of tube assemblies also include a plurality of tubes that extends through the housing. Each of the plurality of tubes is coupled in flow communication with the fluid supply chamber and a combustion chamber positioned downstream from the tube assembly. The plurality of tube assemblies further includes an aft plate at a downstream end of the cooling fluid plenum. The plate includes at least one aperture.

Evaluation of High Pressure Components of Fuel Injection Systems Using Speckle Interferometry

OpenAIRE

Basara, Adis

2007-01-01

The modern high pressure fuel injection systems installed in engines provide a highly efficient combustion process accompanied by low emissions of exhaust gases and an impressive level of dynamic response. The design and development of mechanical components for such systems pose a great challenge, since they have to operate under extremely high fluctuating pressures (e.g. up to 2000 bar) for a long lifetime (more than 1000 injections per minute). The permanent change between a higher and a lo...

Combustion of oil shale, fluidized coal and pyrolysis fuel oil in a gas turbine for electricity generation

Energy Technology Data Exchange (ETDEWEB)

Korosi, A; Basler, B; Pepper, M W

1984-04-01

A combustion test programme has been carried out with a Brown, Boveri and Cie. (BBC) type 9, gas turbine, at the BBC works in Muenchenstein, Switzerland, in order to clarify the combustion possibilities of three unconventional fuels. The programme has been organized and financed by BBC, Stone and Webster and Exxon. Approximately 95,000 litres of each fuel at various turbine load conditions have been burned. At certain points water was injected for NOsub(x) reduction. The tests show that the commercially available gas turbine can be used without modification with these tested, unconventional fuels. They also show that direct application of inferior petrochemical materials, which are produced today, is possible.

Analysis of the Effect of Injection Pressure on Ignition Delay and Combustion Process of Biodiesel from Palm Oil, Algae and Waste Cooking Oil

Science.gov (United States)

Irham Anas, Mohd; Khalid, Amir; Hakim Zulkifli, Fathul; Jaat, Norrizam; Faisal Hushim, Mohd; Manshoor, Bukhari; Zaman, Izzuddin

2017-10-01

Biodiesel is a domestically produced, renewable fuel that can be manufactured from vegetable oils, animal fats, or recycled restaurant grease for use in diesel engines. The objective of this research is investigation the effects of the variant injection pressure on ignition delay and emission for different biodiesel using rapid compression machine. Rapid Compression Machine (RCM) is used to simulate a single compression stroke of an internal combustion engine as a real engine. Four types of biodiesel which are waste cooking oil, crude palm oil, algae and jatropha were tested at injection pressure of 80 MPa, 90 MPa and 130 MPa under constant ambient temperature at 950 K. Increased in injection pressure resulted shorter ignition delay proven by WCO5 which decreased from 1.3 ms at 80 MPa to 0.7 ms at 130 MPa. Meanwhile, emission for CO2 increased due to better fuel atomization for fuel-air mixture formation lead to completed combustion.

An effort to enhance hydrogen energy share in a compression ignition engine under dual-fuel mode using low temperature combustion strategies

International Nuclear Information System (INIS)

Chintala, V.; Subramanian, K.A.

2015-01-01

Highlights: • H 2 energy share increased from 18% with DDM to 36% with WDM (water injection). • H 2 energy share improved marginally with retarded injection timing mode (RDM). • Energy efficiency increased with increasing amount of H 2 in dual-fuel engine. • NO x emission decreased with water injection and retarded pilot fuel injection. • HC, CO and smoke emissions increased slightly with low temperature combustion. - Abstract: A limited hydrogen (H 2 ) energy share due to knocking is the major hurdle for effective utilization of H 2 in compression ignition (CI) engines under dual-fuel operation. The present study aims at improvement of H 2 energy share in a 7.4 kW direct injection CI engine under dual-fuel mode with two low temperature combustion (LTC) strategies; (i) retarded pilot fuel injection timing and (ii) water injection. Experiments were carried out under conventional strategies of diesel dual-fuel mode (DDM) and B20 dual-fuel mode (BDM); and LTC strategies of retarded injection timing dual-fuel mode (RDM) and water injected dual-fuel mode (WDM). The results explored that the H 2 energy share increased significantly from 18% with conventional DDM to 24, and 36% with RDM, and WDM respectively. The energy efficiency increased with increasing H 2 energy share under dual-fuel operation; however, for a particular energy share of 18% H 2 , it decreased from 34.8% with DDM to 33.7% with BDM, 32.7% with WDM and 29.9% with RDM. At 18% H 2 energy share, oxides of nitrogen emission decreased by 37% with RDM and 32% with WDM as compared to conventional DDM due to reduction of in-cylinder temperature, while it increased slightly about 5% with BDM. It is emerged from the study that water injection technique is the viable option among all other strategies to enhance the H 2 energy share in the engine with a slight penalty of increase in smoke, hydrocarbon, and carbon monoxide emissions

Fuel processor for fuel cell power system. [Conversion of methanol into hydrogen

Science.gov (United States)

Vanderborgh, N.E.; Springer, T.E.; Huff, J.R.

1986-01-28

A catalytic organic fuel processing apparatus, which can be used in a fuel cell power system, contains within a housing a catalyst chamber, a variable speed fan, and a combustion chamber. Vaporized organic fuel is circulated by the fan past the combustion chamber with which it is in indirect heat exchange relationship. The heated vaporized organic fuel enters a catalyst bed where it is converted into a desired product such as hydrogen needed to power the fuel cell. During periods of high demand, air is injected upstream of the combustion chamber and organic fuel injection means to burn with some of the organic fuel on the outside of the combustion chamber, and thus be in direct heat exchange relation with the organic fuel going into the catalyst bed.

Combustion characteristics, performance and exhaust emissions of a diesel engine fueled with a waste cooking oil biodiesel mixture

International Nuclear Information System (INIS)

Can, Özer

2014-01-01

Highlights: • High quality biodiesel fuels can be produced by using different waste cooking oils. • Biodiesel fuel blends (in 5 and 10% vol) can be used without any negative effects. • Effects of biodiesel addition on the combustion and exhaust emissions were investigated. - Abstract: In this study, a mixture of biodiesel fuels produced from two different kinds of waste cooking oils was blended in 5% and 10% with No. 2 diesel fuel. The biodiesel/No. 2 diesel fuel blends were tested in a single-cylinder, direct injection, four-stroke, natural aspirated diesel engine under four different engine loads (BMEP 0.48–0.36–0.24–0.12 MPa) and 2200 rpm engine speed. Despite of the earlier start of injection, the detailed combustion and engine performance results showed that the ignition delay with the biodiesel addition was decreased for the all engine loads with the earlier combustion timings due to higher cetane number of biodiesel fuel. Meanwhile the maximum heat release rate and the in-cylinder pressure rise rate were slightly decreased and the combustion duration was generally increased with the biodiesel addition. However, significant changings were not observed on the maximum in-cylinder pressures. In addition, it was observed that the indicated mean effective pressure values were slightly varied depending on the start of combustion timing and the center of heat release location. It was found that 5% and 10% biodiesel fuel addition resulted in slightly increment on break specific fuel consumption (up to 4%) and reduction on break thermal efficiency (up to 2.8%). The biodiesel additions also increased NO x emissions up to 8.7% and decreased smoke and total hydrocarbon emissions for the all engine loads. Although there were no significant changes on CO emissions at the low and medium engine loads, some reductions were observed at the full engine load. Also, CO 2 emissions were slightly increased for the all engine loads

Determination of performance and combustion characteristics of a diesel engine fueled with canola and waste palm oil methyl esters

Energy Technology Data Exchange (ETDEWEB)

Ozsezen, Ahmet Necati [Department of Automotive Engineering Technology, Kocaeli University, 41380 Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Izmit (Turkey); Canakci, Mustafa, E-mail: canakci@kocaeli.edu.t [Department of Automotive Engineering Technology, Kocaeli University, 41380 Izmit (Turkey); Alternative Fuels R and D Center, Kocaeli University, 41040 Izmit (Turkey)

2011-01-15

In this study, the performance, combustion and injection characteristics of a direct injection diesel engine have been investigated experimentally when it was fueled with canola oil methyl ester (COME) and waste (frying) palm oil methyl ester (WPOME). In order to determine the performance and combustion characteristics, the experiments were conducted at constant engine speeds under the full load condition of the engine. The results indicated that when the test engine was fueled with WPOME or COME instead of petroleum based diesel fuel (PBDF), the brake power reduced by 4-5%, while the brake specific fuel consumption increased by 9-10%. On the other hand, methyl esters caused reductions in carbon monoxide (CO) by 59-67%, in unburned hydrocarbon (HC) by 17-26%, in carbon dioxide (CO{sub 2}) by 5-8%, and smoke opacity by 56-63%. However, both methyl esters produced more nitrogen oxides (NO{sub x}) emissions by 11-22% compared with those of the PBDF over the speed range.

Determination of performance and combustion characteristics of a diesel engine fueled with canola and waste palm oil methyl esters

International Nuclear Information System (INIS)

Ozsezen, Ahmet Necati; Canakci, Mustafa

2011-01-01

In this study, the performance, combustion and injection characteristics of a direct injection diesel engine have been investigated experimentally when it was fueled with canola oil methyl ester (COME) and waste (frying) palm oil methyl ester (WPOME). In order to determine the performance and combustion characteristics, the experiments were conducted at constant engine speeds under the full load condition of the engine. The results indicated that when the test engine was fueled with WPOME or COME instead of petroleum based diesel fuel (PBDF), the brake power reduced by 4-5%, while the brake specific fuel consumption increased by 9-10%. On the other hand, methyl esters caused reductions in carbon monoxide (CO) by 59-67%, in unburned hydrocarbon (HC) by 17-26%, in carbon dioxide (CO 2 ) by 5-8%, and smoke opacity by 56-63%. However, both methyl esters produced more nitrogen oxides (NO x ) emissions by 11-22% compared with those of the PBDF over the speed range.

Validation of a zero-dimensional and 2-phase combustion model for dual-fuel compression ignition engine simulation

Directory of Open Access Journals (Sweden)

Mikulski Maciej

2017-01-01

Full Text Available Increasing demands for the reduction of exhaust emissions and the pursuit to re-duce the use of fossil fuels require the search for new fuelling technologies in combustion engines. One of the most promising technologies is the multi-fuel compression ignition engine concept, in which a small dose of liquid fuel injected directly into the cylinder acts as the ignition inhibitor of the gaseous fuel. Achieving the optimum combustion process in such an engine requires the application of advanced control algorithms which require mathematical modelling support. In response to the growing demand for new simulation tools, a 0-D model of a dual-fuel engine was proposed and validated. The validation was performed in a broad range of engine operating points, including various speeds and load condition, as well as different natural gas/diesel blend ratios. It was demonstrated that the average model calculation error within the entire cycle did not exceed 6.2%, and was comparable to the measurement results cycle to cycle variations. The maximum model calculation error in a single point of a cycle was 15% for one of the complex (multipoint injection cases. In other cases, it did not exceed 11%.

Combustion characteristics of the mustard methyl esters

International Nuclear Information System (INIS)

Bannikov, M.G.; Vasilev, I.P.

2011-01-01

Mustard Methyl Esters (further bio diesel) and regular diesel fuel were tested in direct injection diesel engine. Analysis of experimental data was supported by an analysis of fuel injection and combustion characteristics. Engine fuelled with bio diesel had increased brake specific fuel consumption, reduced nitrogen oxides emission and smoke opacity, moderate increase in carbon monoxide emission with essentially unchanged unburned hydrocarbons emission. Increase in fuel consumption was attributed to lesser heating value of bio diesel and partially to decreased fuel conversion efficiency. Analysis of combustion characteristics revealed earlier start of injection and shorter ignition delay period of bio diesel. Resulting decrease in maximum rate of heat release and cylinder pressure was the most probable reason for reduced emission of nitrogen oxides. Analysis of combustion characteristics also showed that cetane index determined by ASTM Method D976 is not a proper measure of ignition quality of bio diesel. Conclusion was made on applicability of mustard oil as a source for commercial production of bio diesel in Pakistan. Potentialities of on improving combustion and emissions characteristics of diesel engine by reformulating bio diesel were discussed. (author)

Improving of diesel combustion-pollution-fuel economy and performance by gasoline fumigation

International Nuclear Information System (INIS)

Şahin, Zehra; Durgun, Orhan

2013-01-01

Highlights: • The effects of gasoline fumigation on the engine performance and NO x emission were investigated in Ford XLD 418 T automotive diesel engine. • Gasoline at approximately (2, 4, 6, 8 10, and 12)% (by vol.) ratios was injected into intake air by a carburetor. • GF enhances effective power and reduces brake specific fuel consumption, cost, and NO x emission. - Abstract: One of the most important objectives of the studies worldwide is to improve combustion of diesel engine to meet growing energy needs and to reduce increasing environmental pollution. To accomplish this goal, especially to reduce pollutant emissions, researchers have focused their interest on the field of alternative fuels and alternative solutions. Gasoline fumigation (GF) is one of these alternative solutions, by which diesel combustion, fuel economy, and engine performance are improved, and environmental pollution is decreased. In the fumigation method, gasoline is injected into intake air, either by a carburetor, which main nozzle section is adjustable or by a simple injection system. In the present experimental study, a simple carburetor was used, and the effects of gasoline fumigation at (2, 4, 6, 8, 10, 12)% (by vol.) gasoline ratios on the combustion, NO x emission, fuel economy, and engine performance sophisticatedly investigated for a fully instrumented, four-cylinder, water-cooled indirect injection (IDI), Ford XLD 418 T automotive diesel engine. Tests were conducted for each of the above gasoline fumigation ratios at three different speeds and for (1/1, 3/4, and 1/2) fuel delivery ratios (FDRs). GF test results showed that NO x emission is lower than that of neat diesel fuel (NDF). NO x emission decreases approximately 4.20%, 2.50%, and 9.65% for (1/1, 3/4, and 1/2) FDRs, respectively. Effective power increases approximately 2.38% for 1/1 FDR. At (2500 and 3000) rpms, effective power decreases at low gasoline ratios, but it increases at high gasoline ratios for 3/4 and 1

Advanced technique for computing fuel combustion properties in pulverized-fuel fired boilers

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R. (Vsesoyuznyi Teplotekhnicheskii Institut (Russian Federation))

1992-03-01

Reviews foreign technical reports on advanced techniques for computing fuel combustion properties in pulverized-fuel fired boilers and analyzes a technique developed by Combustion Engineering, Inc. (USA). Characteristics of 25 fuel types, including 19 grades of coal, are listed along with a diagram of an installation with a drop tube furnace. Characteristics include burn-out intensity curves obtained using thermogravimetric analysis for high-volatile bituminous, semi-bituminous and coking coal. The patented LFP-SKM mathematical model is used to model combustion of a particular fuel under given conditions. The model allows for fuel particle size, air surplus, load, flame height, and portion of air supplied as tertiary blast. Good agreement between computational and experimental data was observed. The method is employed in designing new boilers as well as converting operating boilers to alternative types of fuel. 3 refs.

Effect of injection pressure on performance, emission, and combustion characteristics of diesel-acetylene-fuelled single cylinder stationary CI engine.

Science.gov (United States)

Srivastava, Anmesh Kumar; Soni, Shyam Lal; Sharma, Dilip; Jain, Narayan Lal

2018-03-01

In this paper, the effect of injection pressure on the performance, emission, and combustion characteristics of a diesel-acetylene fuelled single cylinder, four-stroke, direct injection (DI) diesel engine with a rated power of 3.5 kW at a rated speed of 1500 rpm was studied. Experiments were performed in dual-fuel mode at four different injection pressures of 180, 190, 200, and 210 bar with a flow rate of 120 LPH of acetylene and results were compared with that of baseline diesel operation. Experimental results showed that highest brake thermal efficiency of 27.57% was achieved at injection pressure of 200 bar for diesel-acetylene dual-fuel mode which was much higher than 23.32% obtained for baseline diesel. Carbon monoxide, hydrocarbon, and smoke emissions were also measured and found to be lower, while the NO x emissions were higher at 200 bar in dual fuel mode as compared to those in other injection pressures in dual fuel mode and also for baseline diesel mode. Peak cylinder pressure, net heat release rate, and rate of pressure rise were also calculated and were higher at 200 bar injection pressure in dual fuel mode.

Control issues in oxy-fuel combustion

Energy Technology Data Exchange (ETDEWEB)

Snarheim, Dagfinn

2009-08-15

Combustion of fossil fuels is the major energy source in todays society. While the use of fossil fuels is a necessity for our society to function, there has been an increasing concern on the emissions of CO{sub 2} resulting from human activities. Emissions of CO{sub 2} are considered to be the main cause for the global warming and climate changes we have experienced in recent years. To fight the climate changes, the emissions of CO{sub 2} must be reduced in a timely fashion. Strategies to achieve this include switching to less carbon intensive fuels, renewable energy sources, nuclear energy and combustion with CO{sub 2} capture. The use of oxy-fuel combustion is among the alternative post- and pre combustion capture concepts, a strategy to achieve power production from fossil fuels with CO{sub 2} capture. In an oxy-fuel process, the fuel is burned in a mixture of oxygen and CO{sub 2} (or steam), leaving the exhaust consisting mainly of CO{sub 2} and steam. The steam can be removed by use of a condenser, leaving (almost) pure CO{sub 2} ready to be captured. The downside to CO{sub 2} capture is that it is expensive, both in capital cost of extra equipment, and in operation as it costs energy to capture the CO{sub 2}. Thus it is important to maximize the efficiency in such plants. One attractive concept to achieve CO{sub 2} capture by use of oxy-fuel, is a semi-closed oxy-fuel gas turbine cycle. The dynamics of such a plant are highly integrated, involving energy and mass recycle, and optimizing efficiency might lead to operational (control) challenges. In these thesis we investigate how such a power cycle should be controlled. By looking at control at such an early stage in the design phase, it is possible to find control solutions otherwise not feasible, that leads to better overall performance. Optimization is used on a nonlinear model based on first principles, to compare different control structures. Then, closed loop simulations using MPC, are used to validate

Reducing emissions from diesel combustion

International Nuclear Information System (INIS)

Anon.

1992-01-01

This paper contains information dealing with engine design to reduce emissions and improve or maintain fuel economy. Topics include: Observation of High Pressure Fuel Spray with Laser Light Sheet Method; Determination of Engine Cylinder Pressures from Crankshaft Speed Fluctuations; Combustion Similarity for Different Size Diesel Engines: Theoretical Prediction and Experimental Results; Prediction of Diesel Engine Particulate Emission During Transient Cycles; Characteristics and Combustibility of Particulate Matter; Dual-Fuel Diesel Engine Using Butane; Measurement of Flame Temperature Distribution in D.I. Diesel Engine with High Pressure Fuel Injection: and Combustion in a Small DI Diesel Engine at Starting

Combustion Characterization of Bio-derived Fuels and Additives

DEFF Research Database (Denmark)

Hashemi, Hamid

Climate change has become a serious concern nowadays. The main reason is believed to be the high emission of greenhouse gases, namely CO2 which is mainly produced from the combustion of fossil fuels. At the same time, energy demand has increased exponentially while the energy supply mainly depends...... on fossil fuels, especially for transportation. The practical strategy to address such problems in medium term is to increase the efficiency of combustion-propelled energy-production systems, as well as to reduce the net release of CO2 and other harmful pollutants, likely by using nonconventional fuels....... Modern internal combustion engines such as Homogeneous Charge Compression Ignition (HCCI) engines are more efficient and fuel-flexible compared to the conventional engines, making opportunities to reduce the release of greenhouse and other polluting gases to the environment. Combustion temperature...

An experimental investigation into combustion and performance characteristics of an HCCI gasoline engine fueled with n-heptane, isopropanol and n-butanol fuel blends at different inlet air temperatures

International Nuclear Information System (INIS)

Uyumaz, Ahmet

2015-01-01

Highlights: • Combustion was retarded with the increase of the amount of isopropanol and n-butanol in the test fuels. • Combustion was advanced with the increase of air inlet temperature on HCCI combustion. • Isopropanol seems more suitable fuel due to controlling the HCCI combustion and preventing knocking. • Almost zero NO emissions were measured when alcohol used except for n-heptane and B20 test fuels. - Abstract: An experimental study was conducted in a single cylinder, four stroke port injection Ricardo Hydra test engine in order to determine the effects of pure n-heptane, the blends of n-heptane and n-butanol fuels B20, B30, B40 (including 20%, 30%, 40% n-butanol and 80%, 70%, 60% n-heptane by vol. respectively) and the blends of n-heptane and isopropanol fuels P20, P30, P40 (including 20%, 30%, 40% isopropanol and 80%, 70%, 60% n-heptane by vol. respectively) on HCCI combustion. Combustion and performance characteristics of n-heptane, n-butanol and isopropanol were investigated at constant engine speed of 1500 rpm and λ = 2 in a HCCI engine. The effects of inlet air temperature were also examined on HCCI combustion. The test results showed that the start of combustion was advanced with the increasing of inlet air temperature for all test fuels. Start of combustion delayed with increasing percentage of n-butanol and isopropanol in the test fuels. Knocking combustion was seen with B20 and n-heptane test fuels. Minimum combustion duration was observed in case of using B40. Almost zero NO emissions were measured with test fuels apart from n-heptane and B20. The test results also showed that CO and HC emissions decreased with the increase of inlet air temperature for all test fuels. Isopropanol showed stronger resistance for knocking compared to n-butanol in HCCI combustion due to its higher octane number. It was determined that n-butanol was more advantageous according to isopropanol as thermal efficiency. As a result it was found that the HCCI

UV-visible digital imaging of split injection in a Gasoline Direct Injection engine

Directory of Open Access Journals (Sweden)

Merola Simona Silvia

2015-01-01

Full Text Available Ever tighter limits on pollutant emissions and the need to improve energy conversion efficiency have made the application of gasoline direct injection (GDI feasible for a much wider scale of spark ignition engines. Changing the way fuel is delivered to the engine has thus provided increased flexibility but also challenges, such as higher particulate emissions. Therefore, alternative injection control strategies need to be investigated in order to obtain optimum performance and reduced environmental impact. In this study, experiments were carried out on a single-cylinder GDI optical engine fuelled with commercial gasoline in lean-burn conditions. The single-cylinder was equipped with the head of a commercial turbocharged engine with similar geometrical specifications (bore, stroke, compression ratio and wall guided fuel injection. Optical accessibility was ensured through a conventional elongated hollow Bowditch piston and an optical crown, accommodating a fused-silica window. Experimental tests were performed at fixed engine speed and injection pressure, whereas the injection timing and the number of injections were adjusted to investigate their influence on combustion and emissions. UV-visible digital imaging was applied in order to follow the combustion process, from ignition to the late combustion phase. All the optical data were correlated with thermodynamic analysis and measurements of exhaust emissions. Split injection strategies (i.e. two injections per cycle with respect to single injection increased combustion efficiency and stability thanks to an improvement of fuel air mixing. As a consequence, significant reduction in soot formation and exhaust emission with acceptable penalty in terms of HC and NOx were measured.

Improvement of fuel combustion technologies

Energy Technology Data Exchange (ETDEWEB)

Tumanovskii, A.G.; Babii, V.I.; Enyakin, Y.P.; Kotler, V.R.; Ryabov, G.V.; Verbovetskii, E.K.; Nadyrov, I.I. [All-Russian Thermal Engineering Institute, Moscow (Russian Federation)

1996-07-01

The main problems encountered in the further development of fuel combustion technologies at thermal power stations in Russia are considered. Experience is generalized and results are presented on the efficiency with which nitrogen oxide emissions are reduced by means of technological methods when burning natural gas, fuel oil, and coal. The problems that arise in the introduction of new combustion technologies and in using more promising grades of coal are considered. The results studies are presented that show that low grade Russian coals can be burnt in circulating fluidized bed boilers. 14 refs., 5 figs., 4 tabs.

Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber

KAUST Repository

Jing, Wei

2015-01-01

This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O2 concentrations were used, spanning 10-21%. These ambient conditions can be used to mimic practical diesel engine working conditions under different fuel injection timings and exhaust gas recirculation (EGR) levels. Both transient and quasi-steady state analyses were conducted. The transient analysis focused on the flame development from the beginning to the end of the combustion process, illustrating how the flame structure evolves with time. The quasi-steady state analysis concentrated on the stable flame structure and compared the flame emissions in terms of spatially integrated intensity, flame effective area, and intensity per pixel. The transient analysis was based on measurements using high-speed imaging of both OH∗ chemiluminescence and broadband natural luminosity (NL). For the quasi-steady state analysis, three flame narrow-band emissions (OH∗ at 310 nm, Band A at 430 nm and Band B at 470 nm) were captured using an ICCD camera. Based on the current Jet-A data and diesel data obtained from previous experiments, a comparison between Jet-A and diesel was made in terms of flame development during the transient state and spatially integrated intensity, flame effective area, and intensity per pixel during the quasi-steady state. For the transient results, Jet-A shares a similar flame development trend to diesel, but featuring a narrower region of NL and a wider region of OH∗ with the increase of ambient temperature and O2 concentration. The soot cloud is oxidized more quickly for Jet-A than diesel at the end of combustion, evident by comparing the area of NL, especially under high O2 concentration. The quasi-steady state results suggest that soot is oxidized effectively under high O2 concentration conditions by the

Investigation of combustion characteristics of methane-hydrogen fuels

Science.gov (United States)

Vetkin, A. V.; Suris, A. L.; Litvinova, O. A.

2015-01-01

Numerical investigations of combustion characteristics of methane-hydrogen fuel used at present in tube furnaces of some petroleum refineries are carried out and possible problems related to change-over of existing furnaces from natural gas to methane-hydrogen fuel are analyzed. The effect of the composition of the blended fuel, associated temperature and emissivity of combustion products, temperature of combustion chamber walls, mean beam length, and heat release on variation in the radiation heat flux is investigated. The methane concentration varied from 0 to 100%. The investigations were carried out both at arbitrary given gas temperatures and at effective temperatures determined based on solving a set of equations at various heat-release rates of the combustion chamber and depended on the adiabatic combustion temperature and the temperature at the chamber output. The approximation dependence for estimation of the radiation heat exchange rate in the radiant chamber of the furnace at change-over to fuel with a greater hydrogen content is obtained. Hottel data were applied in the present work in connection with the impossibility to use approximated formulas recommended by the normative method for heat calculation of boilers to determine the gas emissivity, which are limited by the relationship of partial pressures of water steam and carbon dioxide in combustion products . The effect of the methane-hydrogen fuel on the equilibrium concentration of nitrogen oxides is also investigated.

Alternate fuels; Combustibles alternos

Energy Technology Data Exchange (ETDEWEB)

Romero Paredes R, Hernando; Ambriz G, Juan Jose [Universidad Autonoma Metropolitana. Iztapalapa (Mexico)

2003-07-01

In the definition and description of alternate fuels we must center ourselves in those technological alternatives that allow to obtain compounds that differ from the traditional ones, in their forms to be obtained. In this article it is tried to give an overview of alternate fuels to the conventional derivatives of petroleum and that allow to have a clear idea on the tendencies of modern investigation and the technological developments that can be implemented in the short term. It is not pretended to include all the tendencies and developments of the present world, but those that can hit in a relatively short term, in accordance with agreed with the average life of conventional fuels. Nevertheless, most of the conversion principles are applicable to the spectrum of carbonaceous or cellulosic materials which are in nature, are cultivated or wastes of organic origin. Thus one will approach them in a successive way, the physical, chemical and biological conversions that can take place in a production process of an alternate fuel or the same direct use of the fuel such as burning the sweepings derived from the forests. [Spanish] En la definicion y descripcion de combustibles alternos nos debemos centrar en aquellas alternativas tecnologicas que permitan obtener compuestos que difieren de los tradicionales, al menos en sus formas de ser obtenidos. En este articulo se pretende dar un panorama de los combustibles alternos a los convencionales derivados del petroleo y que permita tener una idea clara sobre las tendencias de la investigacion moderna y los desarrollos tecnologicos que puedan ser implementados en el corto plazo. No se pretende abarcar todas las tendencias y desarrollos del mundo actual, sino aquellas que pueden impactar en un plazo relativamente corto, acordes con la vida media de los combustibles convencionales. Sin embargo, la mayor parte de los principios de conversion son aplicables al espectro de materiales carbonaceos o celulosicos los cuales se

Modelling the effect of injection pressure on heat release parameters and nitrogen oxides in direct injection diesel engines

Directory of Open Access Journals (Sweden)

Yüksek Levent

2014-01-01

Full Text Available Investigation and modelling the effect of injection pressure on heat release parameters and engine-out nitrogen oxides are the main aim of this study. A zero-dimensional and multi-zone cylinder model was developed for estimation of the effect of injection pressure rise on performance parameters of diesel engine. Double-Wiebe rate of heat release global model was used to describe fuel combustion. extended Zeldovich mechanism and partial equilibrium approach were used for modelling the formation of nitrogen oxides. Single cylinder, high pressure direct injection, electronically controlled, research engine bench was used for model calibration. 1000 and 1200 bars of fuel injection pressure were investigated while injection advance, injected fuel quantity and engine speed kept constant. The ignition delay of injected fuel reduced 0.4 crank angle with 1200 bars of injection pressure and similar effect observed in premixed combustion phase duration which reduced 0.2 crank angle. Rate of heat release of premixed combustion phase increased 1.75 % with 1200 bar injection pressure. Multi-zone cylinder model showed good agreement with experimental in-cylinder pressure data. Also it was seen that the NOx formation model greatly predicted the engine-out NOx emissions for both of the operation modes.

An insight on hydrogen fuel injection techniques with SCR system for NO{sub X} reduction in a hydrogen-diesel dual fuel engine

Energy Technology Data Exchange (ETDEWEB)

Saravanan, N. [ERC Engines, Hall 11A, Tata Motors, Pimpri, Pune 411019, Maharashtra (India); Nagarajan, G. [Department of Mechanical Engineering, ICE Division, College of Engineering, Guindy, Anna University-Chennai, Chennai 600 025 (India)

2009-11-15

Internal combustion engines continue to dominate in many fields like transportation, agriculture and power generation. Among the various alternative fuels, hydrogen is a long-term renewable and less polluting fuel (Produced from renewable energy sources). In the present experimental investigation, the performance and emission characteristics were studied on a direct injection diesel engine in dual fuel mode with hydrogen inducted along with air adopting carburetion, timed port and manifold injection techniques. Results showed that in timed port injection, the specific energy consumption reduces by 15% and smoke level by 18%. The brake thermal efficiency and NO{sub X} increases by 17% and 34% respectively compared to baseline diesel. The variation in performance between port and manifold injection is not significant. The unburnt hydrocarbons and carbon monoxide emissions are lesser in port injection. The oxides of nitrogen are higher in hydrogen operation (both port and manifold injection) compared to diesel engine. In order to reduce the NO{sub X} emissions, a selective catalytic converter was used in hydrogen port fuel injection. The NO{sub X} emission reduced upto a maximum of 74% for ANR (ratio of flow rate of ammonia to the flow rate of NO) of 1.1 with a marginal reduction in efficiency. Selective catalytic reduction technique has been found to be effective in reducing the NO{sub X} emission from hydrogen fueled diesel engines. (author)

Advanced modeling of oxy-fuel combustion of natural gas

Energy Technology Data Exchange (ETDEWEB)

Chungen Yin

2011-01-15

The main goal of this small-scale project is to investigate oxy-combustion of natural gas (NG) through advanced modeling, in which radiation, chemistry and mixing will be reasonably resolved. 1) A state-of-the-art review was given regarding the latest R and D achievements and status of oxy-fuel technology. The modeling and simulation status and achievements in the field of oxy-fuel combustion were also summarized; 2) A computer code in standard c++, using the exponential wide band model (EWBM) to evaluate the emissivity and absorptivity of any gas mixture at any condition, was developed and validated in detail against data in literature. A new, complete, and accurate WSGGM, applicable to both air-fuel and oxy-fuel combustion modeling and applicable to both gray and non-gray calculation, was successfully derived, by using the validated EWBM code as the reference mode. The new WSGGM was implemented in CFD modeling of two different oxy-fuel furnaces, through which its great, unique advantages over the currently most widely used WSGGM were demonstrated. 3) Chemical equilibrium calculations were performed for oxy-NG flame and air-NG flame, in which dissociation effects were considered to different degrees. Remarkable differences in oxy-fuel and air-fuel combustion were revealed, and main intermediate species that play key roles in oxy-fuel flames were identified. Different combustion mechanisms are compared, e.g., the most widely used 2-step global mechanism, refined 4-step global mechanism, a global mechanism developed for oxy-fuel using detailed chemical kinetic modeling (CHEMKIN) as reference. 4) Over 15 CFD simulations were done for oxy-NG combustion, in which radiation, chemistry, mixing, turbulence-chemistry interactions, and so on were thoroughly investigated. Among all the simulations, RANS combined with 2-step and refined 4-step mechanism, RANS combined with CHEMKIN-based new global mechanism for oxy-fuel modeling, and LES combined with different combustion

Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

Directory of Open Access Journals (Sweden)

Jacek Hunicz

2015-01-01

Full Text Available In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

Characterization of Swirl-Venturi Lean Direct Injection Designs for Aviation Gas-Turbine Combustion

Science.gov (United States)

Heath, Christopher M.

2013-01-01

Injector geometry, physical mixing, chemical processes, and engine cycle conditions together govern performance, operability and emission characteristics of aviation gas-turbine combustion systems. The present investigation explores swirl-venturi lean direct injection combustor fundamentals, characterizing the influence of key geometric injector parameters on reacting flow physics and emission production trends. In this computational study, a design space exploration was performed using a parameterized swirl-venturi lean direct injector model. From the parametric geometry, 20 three-element lean direct injection combustor sectors were produced and simulated using steady-state, Reynolds-averaged Navier-Stokes reacting computations. Species concentrations were solved directly using a reduced 18-step reaction mechanism for Jet-A. Turbulence closure was obtained using a nonlinear ?-e model. Results demonstrate sensitivities of the geometric perturbations on axially averaged flow field responses. Output variables include axial velocity, turbulent kinetic energy, static temperature, fuel patternation and minor species mass fractions. Significant trends have been reduced to surrogate model approximations, intended to guide future injector design trade studies and advance aviation gas-turbine combustion research.

Concept for premixed combustion of hydrogen-containing fuels in gas turbines; Konzept zur vorgemischten Verbrennung wasserstoffhaltiger Brennstoffe in Gasturbinen

Energy Technology Data Exchange (ETDEWEB)

Mayer, Christoph

2012-07-19

One of the main challenges for future gas turbines and their combustion systems is to provide fuel flexibility. The fuel range is expected to reach from the lowly reactive natural gas to highly reactive hydrogen-containing syngases. The objective of the project in which this work was pursued is to develop such a combustion system. The burner has to ensure premixed operation with an aerodynamically stabilized flame. The focus of this work is on characterizing and optimizing the operational safety of the system, but also on ensuring sufficientmixing and lowemissions. A burner and fuel injection design is achieved that leads not only to emissions far below the permissible values, but also to flashback safety for hydrogen combustion that comes close to the theoretically achievable maximum at atmospheric pressure conditions. In this design flashback due to combustion-induced vortex breakdown and wall boundary layer flashback is avoided. Flashback only takes place when the flow velocity reaches the flame velocity.

Experimental Study of Injection Characteristics of a Multi-hole port injector on various Fuel Injection pressures and Temperatures

Directory of Open Access Journals (Sweden)

Ommi F

2013-04-01

Full Text Available The structures of the port injector spray dominates the mixture preparation process and strongly affect the subsequent engine combustion characteristics over a wide range of operating conditions in port-injection gasoline engines. All these spray characteristics are determined by particular injector design and operating conditions. In this paper, an experimental study is made to characterize the breakup mechanism and spray characteristics of a injector with multi-disc nozzle (SAGEM,D2159MA. A comparison was made on injection characteristics of the multi-hole injectors and its effects on various fuel pressure and temperature. The distributions of the droplet size and velocity and volume flux were characterized using phase Doppler anemometry (PDA technique. Through this work, it was found that the injector produces a finer spray with a wide spray angle in higher fuel pressure and temperature.

Experimental Study of Injection Characteristics of a Multi-hole port injector on various Fuel Injection pressures and Temperatures

Science.gov (United States)

Movahednejad, E.; Ommi, F.; Nekofar, K.

2013-04-01

The structures of the port injector spray dominates the mixture preparation process and strongly affect the subsequent engine combustion characteristics over a wide range of operating conditions in port-injection gasoline engines. All these spray characteristics are determined by particular injector design and operating conditions. In this paper, an experimental study is made to characterize the breakup mechanism and spray characteristics of a injector with multi-disc nozzle (SAGEM,D2159MA). A comparison was made on injection characteristics of the multi-hole injectors and its effects on various fuel pressure and temperature. The distributions of the droplet size and velocity and volume flux were characterized using phase Doppler anemometry (PDA) technique. Through this work, it was found that the injector produces a finer spray with a wide spray angle in higher fuel pressure and temperature.

Effect of glycerol ethoxylate as an ignition improver on injection and combustion characteristics of hydrous ethanol under CI engine condition

International Nuclear Information System (INIS)

Munsin, R.; Laoonual, Y.; Jugjai, S.; Matsuki, M.; Kosaka, H.

2015-01-01

Highlights: • Glycerol ethoxylate (GE) shows the similar results as the commercial additive. • GE decreases injection rate, but increases injection delay and duration of ethanol. • GE shortens ignition delay and decreases heat released in premixed burn of ethanol. • GE has a minor effect on flame temperature of ethanol. • KL factor and soot of ethanol are sensitive to both GE and the commercial additive. - Abstract: This paper investigates the effects of glycerol ethoxylate as an ignition improver on injection and combustion characteristics of hydrous ethanol under a CI engine condition. Injection characteristics were investigated by an in-house injection rate measurement device based on the Zeuch method, while spray combustion has been performed in the rapid compression and expansion machine (RCEM). The CI engine condition indicated as density, pressure and temperature of compressed synthetic gas, consisting of 80% argon and 20% oxygen, at fuel injection timing in RCEM of 21 kg/m 3 , 4.4 MPa and 900 K, respectively. This condition is equivalent to the isentropic compression of air of the actual CI engine with compression ratio of 22. Hydrous ethanol without ignition improver (Eh95) and the ethanol dedicated for heavy duty vehicles (ED95: composed of hydrous ethanol with the commercial additive for ED95) are reference fuels representing low and high quality ethanol fuel for CI engines, respectively. All test fuels are injected at constant heat input. The results indicate that the additional ignition improvers change injection characteristics, i.e. injection delay, injection rate and discharge coefficient of hydrous ethanol. The maximum injection rates at fully opened needle for the ethanol dedicated for heavy duty vehicles (ED95) and hydrous ethanol with 5% glycerol ethoxylate (5%GE) are lower than that of hydrous ethanol without ignition improver (Eh95) by approximately 10%. Additional injection duration is required for ED95 and 5%GE to maintain a

Numerical Investigation of Injection Timing Influence on Fuel Slip and Influence of Compression Ratio on Knock Occurrence in Conventional Dual Fuel Engine

Directory of Open Access Journals (Sweden)

Mario Sremec

2017-12-01

Full Text Available Compressed natural gas can be used in diesel engine with great benefits, but because of its low reactivity it is usually used in a so called dual fuel combustion process. Optimal parameters for dual fuel engines are not yet investigated thoroughly which is the motivation for this work. In this work, a numerical study performed in a cycle simulation tool (AVL Boost v2013 on the influence of different injection timings on fuel slip into exhaust and influence of compression ratio on knock phenomena in port injected dual fuel engine was conducted. The introduction of natural gas into the intake port of a diesel engine usually results in some fuel slipping into the exhaust port due to valve overlap. By analysing the simulation results, the injection strategy that significantly decreases the natural gas slip is defined. The knock occurrence study showed that the highest allowed compression ratio that will result in knock free operation of the presented engine is 18 for ambient intake condition, while for charged intake conditions the compression ratio should be lowered to 16.

Control of the low-load region in partially premixed combustion

Science.gov (United States)

Ingesson, Gabriel; Yin, Lianhao; Johansson, Rolf; Tunestal, Per

2016-09-01

Partially premixed combustion (PPC) is a low temperature, direct-injection combustion concept that has shown to give promising emission levels and efficiencies over a wide operating range. In this concept, high EGR ratios, high octane-number fuels and early injection timings are used to slow down the auto-ignition reactions and to enhance the fuel and are mixing before the start of combustion. A drawback with this concept is the combustion stability in the low-load region where a high octane-number fuel might cause misfire and low combustion efficiency. This paper investigates the problem of low-load PPC controller design for increased engine efficiency. First, low-load PPC data, obtained from a multi-cylinder heavy- duty engine is presented. The data shows that combustion efficiency could be increased by using a pilot injection and that there is a non-linearity in the relation between injection and combustion timing. Furthermore, intake conditions should be set in order to avoid operating points with unfavourable global equivalence ratio and in-cylinder temperature combinations. Model predictive control simulations were used together with a calibrated engine model to find a gas-system controller that fulfilled this task. The findings are then summarized in a suggested engine controller design. Finally, an experimental performance evaluation of the suggested controller is presented.

Effect of aviation fuel type and fuel injection conditions on the spray characteristics of pressure swirl and hybrid air blast fuel injectors

Science.gov (United States)

Feddema, Rick

Feddema, Rick T. M.S.M.E., Purdue University, December 2013. Effect of Aviation Fuel Type and Fuel Injection Conditions on the Spray Characteristics of Pressure Swirl and Hybrid Air Blast Fuel Injectors. Major Professor: Dr. Paul E. Sojka, School of Mechanical Engineering Spray performance of pressure swirl and hybrid air blast fuel injectors are central to combustion stability, combustor heat management, and pollutant formation in aviation gas turbine engines. Next generation aviation gas turbine engines will optimize spray atomization characteristics of the fuel injector in order to achieve engine efficiency and emissions requirements. Fuel injector spray atomization performance is affected by the type of fuel injector, fuel liquid properties, fuel injection pressure, fuel injection temperature, and ambient pressure. Performance of pressure swirl atomizer and hybrid air blast nozzle type fuel injectors are compared in this study. Aviation jet fuels, JP-8, Jet A, JP-5, and JP-10 and their effect on fuel injector performance is investigated. Fuel injector set conditions involving fuel injector pressure, fuel temperature and ambient pressure are varied in order to compare each fuel type. One objective of this thesis is to contribute spray patternation measurements to the body of existing drop size data in the literature. Fuel droplet size tends to increase with decreasing fuel injection pressure, decreasing fuel injection temperature and increasing ambient injection pressure. The differences between fuel types at particular set conditions occur due to differences in liquid properties between fuels. Liquid viscosity and surface tension are identified to be fuel-specific properties that affect the drop size of the fuel. An open aspect of current research that this paper addresses is how much the type of aviation jet fuel affects spray atomization characteristics. Conventional aviation fuel specifications are becoming more important with new interest in alternative

The effects of hydrous ethanol gasoline on combustion and emission characteristics of a port injection gasoline engine

OpenAIRE

Xiaochen Wang; Zhenbin Chen; Jimin Ni; Saiwu Liu; Haijie Zhou

2015-01-01

Comparative experiments were conducted on a port injection gasoline engine fueled with hydrous ethanol gasoline (E10W), ethanol gasoline (E10) and pure gasoline (E0). The effects of the engine loads and the additions of ethanol and water on combustion and emission characteristics were analyzed deeply. According to the experimental results, compared with E0, E10W showed higher peak in-cylinder pressure at high load. Increases in peak heat release rates were observed for E10W fuel at all the op...

National Jet Fuels Combustion Program – Area #3 : Advanced Combustion Tests

Science.gov (United States)

2017-12-31

The goal of this study is to develop, conduct, and analyze advanced laser and optical measurements in the experimental combustors developed under ASCENT National Fuel Combustion Program to measure sensitivity to fuel properties. We conducted advanced...

Second law comparison of oxy-fuel combustion and post-combustion carbon dioxide separation

International Nuclear Information System (INIS)

Simpson, Adam P.; Simon, A.J.

2007-01-01

To define 2nd law efficiency targets for novel separation technologies, a simplified model of a power plant with two forms of CO 2 capture was developed. In this investigation, oxy-fuel combustion and post-combustion CO 2 separation were compared on an exergetic basis. Using exergy balances and black-box models of power plant components, multiple scenarios were run to determine the impact of plant configuration and separation unit efficiency on overall plant performance. Second law efficiency values from the literature were used to set the baseline performance of various CO 2 separation configurations. Assumed advances in 2nd law efficiency were used to determine the potential for overall system performance improvement. It was found that the 2nd law efficiency of air separation must reach a critical value before the thermodynamics of oxy-fuel combustion become favorable. Changes in operating equivalence ratio significantly move the tipping-point between post-combustion and oxy-fuel strategies

Combustion of Refuse Derived Fuels; Foerbraenning av utsorterade avfallsfraktioner

Energy Technology Data Exchange (ETDEWEB)

Berg, Magnus; Wikman, Karin [AaF-Energi och Miljoe, Stockholm (Sweden); Andersson, Christer; Myringer, Aase; Helgesson, Anna [Vattenfall Utveckling AB, Aelvkarleby (Sweden); Eskilsson, David; Ekvall, Annika [SP Swedish National Testing and Research Inst., Boraas (Sweden); Oehman, Marcus; Geyter, Sigrid de [Umeaa Univ. (Sweden). Energy Technology and Thermal Process Chemistry

2005-03-01

the different fuel mixtures shows that addition of PWP-fuel results in locally lower O{sub 2}-levels and higher CO-levels close to the front wall. This results in an increased risk for local corrosion on the furnace walls. The measurements in Johannes showed that co-combustion with PWP increased the alkali chloride concentration in the flue gas but an increase in the amount of deposits could not be measured. However, the deposits contained more chlorine during co-combustion of PWP, which should yield increased risk for corrosion. The increase can be correlated with the wood and paper fractions of the fuel. Injection of sulphate in the furnace resulted in increased SO{sub 2} concentration and reduced alkali chloride concentration, which resulted in reduced deposit formation. Addition of sulphate also reduced the chlorine concentration in the deposits thereby reducing the corrosion risk. The sub micron particles in the flue gas before gas cleaning mainly contain KCl and K2SO{sub 4} but with sulphate addition KCl to a large extent is converted to K{sub 2}SO{sub 4}. Altogether, this shows that this kind of fuel yields an increased risk for corrosion and deposits on superheaters and furnace walls. However, these problems can to a large extent be avoided by the addition of sulphur (concerning superheater corrosion) and adjustment of the air and fuel feed equipment (concerning furnace wall corrosion). Also in the tests in Hoegdalen the SO{sub 2} concentration increased and the alkali chloride concentration decreased in the flue gas when sulphur was added, resulting in decreased deposit formation. At the same time the chlorine concentration decreased and the sulphur concentration increased in the deposits. However, the chlorine concentration of the deposits was still high and did not decrease as much as in Johannes. Using elementary sulphur or sulphate as an additive had no noticeable influence on deposit growth or on the chemical composition of the deposits. Neither did the

Development and application of multi-zone model for combustion and pollutants formation in direct injection diesel engine running with vegetable oil or its bio-diesel

International Nuclear Information System (INIS)

Rakopoulos, C.D.; Antonopoulos, K.A.; Rakopoulos, D.C.

2007-01-01

A multi-zone model for calculation of the closed cycle of a direct injection (DI) Diesel engine is presented and applied for the interesting case of its operation with vegetable oil (cottonseed) or its derived bio-diesel (methyl ester) as fuels, which recently are considered as promising alternatives (bio-fuels) to petroleum distillates. Although there are many experimental studies, there is an apparent scarcity of theoretical models scrutinizing the formation mechanisms of combustion generated emissions when using these fuels. The model is two dimensional, multi-zone with the issuing jets (from the nozzle) divided into several discrete volumes, called 'zones', formed along the direction of the fuel injection and across it. The model follows each zone, with its own time history, as the spray penetrates into the swirling air environment (forming the non-burning zone) of the combustion chamber, before and after wall impingement. Droplet evaporation and jet mixing models are used to determine the amount of fuel and entrained air in each zone available for combustion. The mass, energy and state equations are applied in each zone to yield local temperatures and cylinder pressure histories. The concentrations of the various constituents are calculated by adopting a chemical equilibrium scheme for the C-H-O-N system of 11 species considered, together with the chemical rate equations for the calculation of nitric oxide (NO). A model for evaluation of soot formation and oxidation rates is included. The results from the relevant computer program for the in cylinder pressure, exhaust nitric oxide concentration (NO) and soot density are compared favorably with the corresponding measurements from an experimental investigation conducted on a fully automated test bed, standard 'Hydra', DI Diesel engine installed at the authors' laboratory. Iso-contour plots of equivalence ratio, temperature, NO and soot inside the combustion chamber at various instants of time when using these

Spray combustion of Jet-A and diesel fuels in a constant volume combustion chamber

International Nuclear Information System (INIS)

Jing, Wei; Roberts, William L.; Fang, Tiegang

2015-01-01

This work investigates the spray combustion of Jet-A fuel in an optical constant-volume combustion chamber under different ambient initial conditions. Ambient temperature was varied at 800 K, 1000 K, and 1200 K and five different ambient O 2 concentrations were used, spanning 10–21%. These ambient conditions can be used to mimic practical diesel engine working conditions under different fuel injection timings and exhaust gas recirculation (EGR) levels. Both transient and quasi-steady state analyses were conducted. The transient analysis focused on the flame development from the beginning to the end of the combustion process, illustrating how the flame structure evolves with time. The quasi-steady state analysis concentrated on the stable flame structure and compared the flame emissions in terms of spatially integrated intensity, flame effective area, and intensity per pixel. The transient analysis was based on measurements using high-speed imaging of both OH ∗ chemiluminescence and broadband natural luminosity (NL). For the quasi-steady state analysis, three flame narrow-band emissions (OH ∗ at 310 nm, Band A at 430 nm and Band B at 470 nm) were captured using an ICCD camera. Based on the current Jet-A data and diesel data obtained from previous experiments, a comparison between Jet-A and diesel was made in terms of flame development during the transient state and spatially integrated intensity, flame effective area, and intensity per pixel during the quasi-steady state. For the transient results, Jet-A shares a similar flame development trend to diesel, but featuring a narrower region of NL and a wider region of OH ∗ with the increase of ambient temperature and O 2 concentration. The soot cloud is oxidized more quickly for Jet-A than diesel at the end of combustion, evident by comparing the area of NL, especially under high O 2 concentration. The quasi-steady state results suggest that soot is oxidized effectively under high O 2 concentration conditions by

High pressure combustion of liquid fuels. [alcohol and n-paraffin fuels

Science.gov (United States)

Canada, G. S.

1974-01-01

Measurements were made of the burning rates and liquid surface temperatures for a number of alcohol and n-paraffin fuels under natural and forced convection conditions. Porous spheres ranging in size from 0.64-1.9 cm O.D. were emloyed to simulate the fuel droplets. The natural convection cold gas tests considered the combustion in air of methanol, ethanol, propanol-1, n-pentane, n-heptane, and n-decane droplets at pressures up to 78 atmospheres. The pressure levels of the natural convection tests were high enough so that near critical combustion was observed for methanol and ethanol vaporization rates and liquid surface temperature measurements were made of droplets burning in a simulated combustion chamber environment. Ambient oxygen molar concentrations included 13%, 9.5% and pure evaporation. Fuels used in the forced convection atmospheric tests included those listed above for the natural convection tests. The ambient gas temperature ranged from 600 to 1500 K and the Reynolds number varied from 30 to 300. The high pressure forced convection tests employed ethanol and n-heptane as fuels over a pressure range of one to 40 atmospheres. The ambient gas temperature was 1145 K for the two combustion cases and 1255 K for the evaporation case.

Fuel Flexible Combustion Systems for High-Efficiency Utilization of Opportunity Fuels in Gas Turbines

Energy Technology Data Exchange (ETDEWEB)

Venkatesan, Krishna

2011-11-30

The purpose of this program was to develop low-emissions, efficient fuel-flexible combustion technology which enables operation of a given gas turbine on a wider range of opportunity fuels that lie outside of current natural gas-centered fuel specifications. The program encompasses a selection of important, representative fuels of opportunity for gas turbines with widely varying fundamental properties of combustion. The research program covers conceptual and detailed combustor design, fabrication, and testing of retrofitable and/or novel fuel-flexible gas turbine combustor hardware, specifically advanced fuel nozzle technology, at full-scale gas turbine combustor conditions. This project was performed over the period of October 2008 through September 2011 under Cooperative Agreement DE-FC26-08NT05868 for the U.S. Department of Energy/National Energy Technology Laboratory (USDOE/NETL) entitled "Fuel Flexible Combustion Systems for High-Efficiency Utilization of Opportunity Fuels in Gas Turbines". The overall objective of this program was met with great success. GE was able to successfully demonstrate the operability of two fuel-flexible combustion nozzles over a wide range of opportunity fuels at heavy-duty gas turbine conditions while meeting emissions goals. The GE MS6000B ("6B") gas turbine engine was chosen as the target platform for new fuel-flexible premixer development. Comprehensive conceptual design and analysis of new fuel-flexible premixing nozzles were undertaken. Gas turbine cycle models and detailed flow network models of the combustor provide the premixer conditions (temperature, pressure, pressure drops, velocities, and air flow splits) and illustrate the impact of widely varying fuel flow rates on the combustor. Detailed chemical kinetic mechanisms were employed to compare some fundamental combustion characteristics of the target fuels, including flame speeds and lean blow-out behavior. Perfectly premixed combustion experiments were conducted to

Heavy-Duty Low-Temperature and Diesel Combustion & Heavy-Duty Combustion Modeling

Energy Technology Data Exchange (ETDEWEB)

Musculus, Mark P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-11-01

Regulatory drivers and market demands for lower pollutant emissions, lower carbon dioxide emissions, and lower fuel consumption motivate the development of clean and fuel-efficient engine operating strategies. Most current production engines use a combination of both in-cylinder and exhaust emissions-control strategies to achieve these goals. The emissions and efficiency performance of in-cylinder strategies depend strongly on flow and mixing processes associated with fuel injection. Various diesel engine manufacturers have adopted close-coupled post-injection combustion strategies to both reduce pollutant emissions and to increase engine efficiency for heavy-duty applications, as well as for light- and medium-duty applications. Close-coupled post-injections are typically short injections that follow a larger main injection in the same cycle after a short dwell, such that the energy conversion efficiency of the post-injection is typical of diesel combustion. Of the various post-injection schedules that have been reported in the literature, effects on exhaust soot vary by roughly an order of magnitude in either direction of increasing or decreasing emissions relative to single injections (O’Connor et al., 2015). While several hypotheses have been offered in the literature to help explain these observations, no clear consensus has been established. For new engines to take full advantage of the benefits that post-injections can offer, the in-cylinder mechanisms that affect emissions and efficiency must be identified and described to provide guidance for engine design.

Combustion of solid alternative fuels in the cement kiln burner

DEFF Research Database (Denmark)

Nørskov, Linda Kaare

In the cement industry there is an increasing environmental and financial motivation for substituting conventional fossil fuels with alternative fuels, being biomass or waste derived fuels. However, the introduction of alternative fuels may influence emissions, cement product quality, process...... stability, and process efficiency. Alternative fuel substitution in the calciner unit has reached close to 100% at many cement plants and to further increase the use of alternative fuels rotary kiln substitution must be enhanced. At present, limited systematic knowledge of the alternative fuel combustion...... properties and the influence on the flame formation is available. In this project a scientific approach to increase the fundamental understanding of alternative fuel conversion in the rotary kiln burner is employed through literature studies, experimental combustion characterisation studies, combustion...

Combustion characterization of beneficiated coal-based fuels

Energy Technology Data Exchange (ETDEWEB)

Chow, O.K.; Levasseur, A.A.

1995-11-01

The Pittsburgh Energy Technology Center (PETC) of the U.S. Department of Energy is sponsoring the development of advanced coal-cleaning technologies aimed at expanding the use of the nation`s vast coal reserves in an environmentally and economically acceptable manner. Because of the lack of practical experience with deeply beneficiated coal-based fuels, PETC has contracted Combustion Engineering, Inc. to perform a multi-year project on `Combustion Characterization of Beneficiated Coal-Based Fuels.` The objectives of this project include: (1) the development of an engineering data base which will provide detailed information on the properties of Beneficiated Coal-Based Fuels (BCs) influencing combustion, ash deposition, ash erosion, particulate collection, and emissions; and (2) the application of this technical data base to predict the performance and economic impacts of firing the BCFs in various commercial boiler designs.

Use of combustible wastes as fuel

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.; Salamov, A.A.

1983-01-01

Achievements of science and technology in creating and using units for combustion of wastes with recovery of heat of the escaping gases has been systematized and generalized. Scales and outlooks are examined for the use of general, industrial and agricultural waste as fuel, composition of the waste, questions of planning and operating units for combustion of solid refuse, settling of waste water and industrial and agricultural waste. Questions are covered for preparing them for combustion use in special units with recovery of heat and at ES, aspects of environmental protection during combustion of waste, cost indicators of the employed methods of recovering the combustible waste.

Multidimensional modeling of the effect of fuel injection pressure on temperature distribution in cylinder of a turbocharged DI diesel engine

Directory of Open Access Journals (Sweden)

Sajjad Emami

2013-06-01

Full Text Available In this study, maintaining a constant fuel rate, injection pressure of 275 bar to 1000 bar (275×102 kPa to 1000×102 kPa, has been changed. Effect of injection pressure, the pressure inside the cylinder on the free energy, power, engine indicators, particularly indicators of fuel consumption, pollutants and their effects on parameters affecting the output of the engine combustion chamber have been studied in droplet diameter. Finally, the effects of fuel mixture equivalence, Cantor temperature, soot and NOx due to the increase of injection pressure, engine efficiency and emissions have been examined.

Realisations in the field of combustion for a new type of gaseous fuel based on hydrogen

Energy Technology Data Exchange (ETDEWEB)

Paunescu, L.; Surugiu, G. [Metallurgical Research Inst., Bucharest (Romania); Dica, C. [Rokura Industrial Applications, Bucharest (Romania); Stanescu, P.D. [Univ. for Technical Installation, Bucharest (Romania); Iorga, G. [Uzinsider Engineering, Galati (Romania); Necula, H. [Politechnica Univ., Bucharest (Romania); Ivan, I. [Mittal Steel, Galati (Romania)

2006-07-01

The trend towards the use of non-polluting energy sources to reduce or eliminate environmentally damaging combustion products such as carbon dioxide, carbon monoxide and nitrous oxides was discussed. Water electrolysis experiments were conducted to obtain an oxy-hydric gaseous fuel known as Klein gas. Klein gas contains hydrogen and oxygen in an almost stoichiometric proportion and has a unique molecular structure. From an energetic point of view, Klein gas behaves differently from other gases depending on the conditions where ignition and combustion occur. The temperature inside the flame varies from about 130 degrees C during free combustion under normal temperature and pressure conditions, up to the melting temperatures of some metals or refractory materials. If ignited Klein gas comes in contact with the surfaces of such a materials it can be used for cutting, brazing or welding. In order to use Klein gas in combustion installations such as industrial heating furnaces in iron and steel mills or in the ceramic and refractory industry, it should be used in combination with other gaseous fuels before ignition or by injection into an existing flame. This paper presented experimental results obtained by a Romanian team of researchers regarding the use of Klein gas in combustion installations with natural gas. The combustion rate was found to intensify as flame temperature increased, depending on the proportion of Klein gas used. The optimal proportion between the two fuels was found to be 1:5. 5 refs., 3 tabs., 4 figs.

A new concept of auxiliary fuel injection through tuyeres in blast furnaces developed by numerical simulations

Directory of Open Access Journals (Sweden)

Bruno Orlando de Almeida Santos

2014-04-01

Full Text Available The Injection of powdered materials in blast furnaces is a great option for reducing costs, increasing productivity and satisfy the environmental norms. Thus, this paper presents a study on the use of a flame stabilization system with rotation, designed to promote greater coal injection in the combustion zone, reducing losses and increasing the efficiency of the equipment. A physical model was used to evaluate scattering of pulverized fuel and is compared with numerical results in the same scale. In the second step, a combustion model was added to the numerical simulation, using dimensions of a real blast furnace. Fields like temperature, velocity and behavior of chemical reactions were analyzed. The results showed that double lances promote better particle injection when compared with simple lance for reduced material injection. The new injection system proposed, with swirl numbers of 0.12 and 0.24, promoted a better injection of both reduced material and temperature in the raceway zone. The swirl 0.24 showed superior performance when compared to other injection systems.

A method for determining the completeness of fuel combustion

Energy Technology Data Exchange (ETDEWEB)

Tavger, M.D.; Chepkin, V.M.; Gruzdev, V.N.; Talantov, A.V.

1982-01-01

The current of conductivity (ionization) of gaseous combustion products, which forms with feeding of electric voltage to a special probe, is proposed for determining the completeness of fuel combustion. Here, the charged particles are formed from substances which form in the intermediate stages of the combustion reaction. The volume of charged particles is proportional to the volume of the intermediate substances, whose presence attests to the incompleteness of the combustion reaction. The fullness of fuel combustion is determined from a formula which includes the stoichiometric coefficient, a gas constant, the energy of activation, the characteristics of the chemical activity of the intermediate substances, the coefficient of air excess, the temperature of the combustion products and the conductivity current.

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.

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)

Improvements of diesel combustion with pilot and main injections at different piston positions; Piston iso wo koryoshita pilot funsha ni yoru diesel nenshono kaizen

Energy Technology Data Exchange (ETDEWEB)

Li, C.; Ogawa, H.; Miyamoto, N. [Hokkaido University, Sapporo (Japan); Sakai, A. [Nissan Motor Co. Ltd., Tokyo (Japan)

2000-06-25

The fuel spray distribution in a DI diesel engine with a pilot injection was actively controlled by pilot and main fuel injections at different piston positions to avoid the main fuel injection from hitting the pilot flame. A CFD analysis demonstrated that the movement of the piston with a cavity divided by a central lip along the center of the sidewall effectively separated the cores of the pilot and main fuel sprays. The experiments showed that more smoke was emitted with pilot injection in an ordinary cavity without the central lip while smokeless and low NO{sub x} operation was realized with pilot injection in a cavity divided by a central lip even at heavy loads where ordinary operation without pilot injection emitted smoke so much. The indicated specific energy consumption ISEC was a little bit higher with the pilot injection, mainly because of the reduction in the degree of constant volume combustion. With the advanced pilot injection, ISEC was improved more than that with the retarded pilot injection while the NO{sub x} is a little higher than the retarded pilot injection maintaining still much lower than in ordinary operation. (author)

Steam-moderated oxy-fuel combustion

International Nuclear Information System (INIS)

Seepana, Sivaji; Jayanti, Sreenivas

2010-01-01

The objective of the present paper is to propose a new variant of the oxy-fuel combustion for carbondioxide (CO 2 ) sequestration in which steam is used to moderate the flame temperature. In this process, pure oxygen is mixed with steam and the resulting oxidant mixture is sent to the boiler for combustion with a fossil fuel. The advantage of this method is that flue gas recirculation is avoided and the volumetric flow rates through the boiler and auxiliary components is reduced by about 39% when compared to the conventional air-fired coal combustion power plant leading to a reduction in the size of the boiler. The flue gas, after condensation of steam, consists primarily of CO 2 and can be sent directly for compression and sequestration. Flame structure analysis has been carried out using a 325-step reaction mechanism of methane-oxidant combustion to determine the concentration of oxygen required to ensure a stable flame. Thermodynamic exergy analysis has also been carried out on SMOC-operated CO 2 sequestration power plant and air-fired power plant, which shows that though the gross efficiency increases the absolute power penalty of ∼8% for CO 2 sequestration when compared to air-fired power plant.

Steam-moderated oxy-fuel combustion

Energy Technology Data Exchange (ETDEWEB)

Seepana, Sivaji; Jayanti, Sreenivas [Department of Chemical Engineering, IIT Madras, Adyar, Chennai 600 036 (India)

2010-10-15

The objective of the present paper is to propose a new variant of the oxy-fuel combustion for carbondioxide (CO{sub 2}) sequestration in which steam is used to moderate the flame temperature. In this process, pure oxygen is mixed with steam and the resulting oxidant mixture is sent to the boiler for combustion with a fossil fuel. The advantage of this method is that flue gas recirculation is avoided and the volumetric flow rates through the boiler and auxiliary components is reduced by about 39% when compared to the conventional air-fired coal combustion power plant leading to a reduction in the size of the boiler. The flue gas, after condensation of steam, consists primarily of CO{sub 2} and can be sent directly for compression and sequestration. Flame structure analysis has been carried out using a 325-step reaction mechanism of methane-oxidant combustion to determine the concentration of oxygen required to ensure a stable flame. Thermodynamic exergy analysis has also been carried out on SMOC-operated CO{sub 2} sequestration power plant and air-fired power plant, which shows that though the gross efficiency increases the absolute power penalty of {proportional_to}8% for CO{sub 2} sequestration when compared to air-fired power plant. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Saanum, Inge

2008-07-01

. % hydrogen to the methane, but 5 vol. % hydrogen also resulted in a noticeable increase. The flame structure was also influenced by the hydrogen addition as the flame front had a higher tendency to become wrinkled or cellular. The effect is believed to mainly be caused by a reduction in the effective Lewis number of the mixture. In the gas engine experiments, the effect of adding 25 vol. % hydrogen to natural gas was investigated when the engine was run on lean air/fuel mixtures and on stoichiometric mixtures with exhaust gas recirculation. The hydrogen addition was found to extend the lean limit of stable combustion and hence caused lower NO{sub x} emissions. The brake thermal efficiency increased with the hydrogen addition, both for the fuel lean and the stoichiometric mixtures with exhaust gas recirculation. This is mainly because of shorter combustion durations when the hydrogen mixture was used, leading to thermodynamically improved cycles. Two types of experiments were performed in compression ignition engines. First, homogenous charge compression ignition (HCCI) experiments were performed in a single cylinder engine fueled with natural gas and diesel oil. As HCCI engines have high thermal efficiency and low NO{sub x} and PM emissions it may be more favorable to use natural gas in HCCI engines than in spark ignition engines. The mixture of natural gas, diesel oil and air was partly premixed before combustion. The natural gas/diesel ratio was used to control the ignition timing as the fuels have very different ignition properties. The natural gas was also replaced by a 20 vol. % hydrogen/natural gas mixture to study the effect of hydrogen on the ignition and combustion process. Also, rape seed methyl ester (RME) was tested instead of the diesel oil. The combustion phasing was found to mainly be controlled by the amount of liquid fuel injected. The last experiments with compression ignition were performed by using a standard Scania diesel engine where the possibilities

Pulsed, supersonic fuel jets-A review of their characteristics and potential for fuel injection

International Nuclear Information System (INIS)

Milton, B.E.; Pianthong, K.

2005-01-01

High pressure fuel injection has provided considerable benefits for diesel engines, substantially reducing smoke levels while increasing efficiency. Current maximum pressures provide jets that are at less than the sonic velocity of the compressed air in the cylinders at injection. It has been postulated that a further increase into the supersonic range may benefit the combustion process due to increased aerodynamic atomization and the presence of jet bow shock waves that provide higher temperatures around the fuel. Pulsed, supersonic injection may also be beneficial for scramjet engines. The current program is examining pulsed, supersonic jets from a fundamental viewpoint both experimentally and numerically. Shock wave structures have been viewed for jets ranging from 600 to 2400 m/s, velocity attenuation and penetration distance measured, different nozzle designs examined and autoignition experiments carried out. Inside the nozzle, numerical simulation using the Autodyne code has been used to support an analytic approach while in the spray, the FLUENT code has been used. While benefits have not yet been defined, it appears that some earlier claims regarding autoignition at atmospheric conditions were optimistic but that increased evaporation and mixing are probable. The higher jet velocities are likely to mean that wall interactions are increased and hence matching such injectors to engine size and airflow patterns will be important

Investigation into the effect of different fuels on ignition delay of M-type diesel combustion process

Directory of Open Access Journals (Sweden)

Bibić Dževad

2008-01-01

Full Text Available An ignition delay is a very complex process which depends on a great number of parameters. In practice, definition of the ignition delay is based on the use of correlation expressions. However, the correlation expressions have very often limited application field. This paper presents a new correlation which has been developed during the research project on the direct injection M-type diesel engine using both the diesel and biodiesel fuel, as well as different values of a static injection timing. A dynamic start of injection, as well as the ignition delay, is defined in two ways. The first approach is based on measurement of a needle lift, while the second is based on measurement of a fuel pressure before the injector. The latter approach requires calculation of pressure signals delay through the fuel injection system and the variation of a static advance injection angle changing. The start of a combustion and the end of the ignition delay is defined on the basis of measurements of an in-cylinder pressure and its point of separation from a skip-fire pressure trace. The developed correlation gives better prediction of the ignition delay definition for the M-type direct injection diesel engine in the case of diesel and biodiesel fuel use when compared with the classic expression by the other authors available in the literature.

Combustion Characterization and Ignition Delay Modeling of Low- and High-Cetane Alternative Diesel Fuels in a Marine Diesel Engine

OpenAIRE

Petersen, John; Seivwright, Doug; Caton, Patrick; Millsaps, Knox

2014-01-01

The article of record as published may be found at http://dx.doi.org/10.1021/ef500565t In support of an ongoing U.S. Navy alternative fuel evaluation program, the combustion characteristics of two very different alternative diesel fuels were evaluated in a direct-injection marine diesel engine across a variety of speeds and loads. The fuels were an algal-based hydrotreated renewable diesel fuel (HRD) with cetane number of ∼75 and a synthetic paraffinic kerosene (SPK) with cetane n...

Modeling analysis of urea direct injection on the NOx emission reduction of biodiesel fueled diesel engines

International Nuclear Information System (INIS)

An, H.; Yang, W.M.; Li, J.; Zhou, D.Z.

2015-01-01

Highlights: • The effects of urea direct injection on NO x emissions reduction was investigated. • Aqueous urea solution was proposed to be injected after the fuel injection process. • The optimized injection strategy achieved a reduction efficiency of 58%. • There were no severe impacts on the CO emissions and BSFC. - Abstract: In this paper, a numerical simulation study was conducted to explore the possibility of an alternative approach: direct aqueous urea solution injection on the reduction of NO x emissions of a biodiesel fueled diesel engine. Simulation studies were performed using the 3D CFD simulation software KIVA4 coupled with CHEMKIN II code for pure biodiesel combustion under realistic engine operating conditions of 2400 rpm and 100% load. The chemical behaviors of the NO x formation and urea/NO x interaction processes were modeled by a modified extended Zeldovich mechanism and urea/NO interaction sub-mechanism. To ensure an efficient NO x reduction process, various aqueous urea injection strategies in terms of post injection timing, injection angle, and injection rate and urea mass fraction were carefully examined. The simulation results revealed that among all the four post injection timings (10 °ATDC, 15 °ATDC, 20 °ATDC and 25 °ATDC) that were evaluated, 15 °ATDC post injection timing consistently demonstrated a lower NO emission level. The orientation of the aqueous urea injection was also shown to play a critical role in determining the NO x removal efficiency, and 50 degrees injection angle was determined to be the optimal injection orientation which gave the most NO x reduction. In addition, both the urea/water ratio and aqueous urea injection rate demonstrated important roles which affected the thermal decomposition of urea into ammonia and the subsequent NO x removal process, and it was suggested that 50% urea mass fraction and 40% injection rate presented the lowest NO emission levels. At last, with the optimized injection

Fundamental characterization of alternate fuel effects in continuous combustion systems

Energy Technology Data Exchange (ETDEWEB)

Blazowski, W.S.; Edelman, R.B.; Harsha, P.T.

1978-09-11

The overall objective of this contract is to assist in the development of fuel-flexible combustion systems for gas turbines as well as Rankine and Stirling cycle engines. The primary emphasis of the program is on liquid hydrocarbons produced from non-petroleum resouces. Fuel-flexible combustion systems will provide for more rapid transition of these alternate fuels into important future energy utilization centers (especially utility power generation with the combined cycle gas turbine). The specific technical objectives of the program are to develop an improved understanding of relationships between alternate fuel properties and continuous combustion system effects, and to provide analytical modeling/correlation capabilities to be used as design aids for development of fuel-tolerant combustion systems. Efforts this past year have been to evaluate experimental procedures for studying alternate fuel combustion effects and to determine current analytical capabilities for prediction of these effects. Jet Stirred Combustor studies during this period have produced new insights into soot formation in strongly backmixed systems and have provided much information for comparison with analytical predictions. The analytical effort included new applications of quasi-global modeling techniques as well as comparison of prediction with the experimental results generated.

Experimental and theoretical study on spray behaviors of modified bio-ethanol fuel employing direct injection system

Directory of Open Access Journals (Sweden)

Ghahremani Amirreza

2017-01-01

Full Text Available One of the key solutions to improve engine performance and reduce exhaust emissions of internal combustion engines is direct injection of bio-fuels. A new modified bio-ethanol is produced to be substituted by fossil fuels in gasoline direct injection engines. The key advantages of modified bio-ethanol fuel as an alternative fuel are higher octane number and oxygen content, a long-chain hydro-carbon fuel, and lower emissions compared to fossil fuels. In the present study spray properties of a modified bio-ethanol and its atomization behaviors have been studied experimentally and theoretically. Based on atomization physics of droplets dimensional analysis has been performed to develop a new non-dimensional number namely atomization index. This number determines the atomization level of the spray. Applying quasi-steady jet theory, air entrainment and fuel-air mixing studies have been performed. The spray atomization behaviors such as atomization index number, Ohnesorge number, and Sauter mean diameter have been investigated employing atomization model. The influences of injection and ambient conditions on spray properties of different blends of modified bio-ethanol and gasoline fuels have been investigated performing high-speed visualization technique. Results indicate that decreasing the difference of injection and ambient pressures increases spray cone angle and projected area, and decreases spray tip penetration length. As expected, increasing injection pressure improves atomization behaviors of the spray. Increasing percentage of modified bio-ethanol in the blend, increases spray tip penetration and decreases the projected area as well.

Influence of injection timing on DI diesel engine characteristics fueled with waste transformer oil

Directory of Open Access Journals (Sweden)

S. Prasanna Raj Yadav

2015-12-01

Full Text Available This research work targets on the effective utilization of WTO (waste transformer oil in a diesel engine, which would rather reduce environmental problems caused by disposing of it in the open land. The waste transformer oil was compared with the conventional diesel fuel and found that it can also be used as fuel in compression ignition engines since the WTO is also a derivative of crude oil. In this present work, the WTO has been subjected to traditional base-catalyzed trans-esterification process in order to reduce the high viscosity of the WTO which helps to effectively utilize WTO as a fuel in DI diesel engine. The objective of the work is to study the influence of injection timing on the performance, emission and combustion characteristics of a single cylinder, four stroke, direct injection diesel engine using TWTO (trans-esterified waste transformer oil as a fuel. Experiments were performed at four injection timings (23°, 22°, 21°, and 20° bTDC. The results indicate that the retarded injection timing of 20° bTDC resulted in decreased oxides of nitrogen, carbon monoxide and unburned hydrocarbon by 11.57%, 17.24%, and 10% respectively while the brake thermal efficiency and smoke increased under all the load conditions when compared to that of standard injection timing.

Numerical and Experimental Investigation of Combustion and Knock in a Dual Fuel Gas/Diesel Compression Ignition Engine

Directory of Open Access Journals (Sweden)

A. Gharehghani

2012-01-01

Full Text Available Conventional compression ignition engines can easily be converted to a dual fuel mode of operation using natural gas as main fuel and diesel oil injection as pilot to initiate the combustion. At the same time, it is possible to increase the output power by increasing the diesel oil percentage. A detailed performance and combustion characteristic analysis of a heavy duty diesel engine has been studied in dual fuel mode of operation where natural gas is used as the main fuel and diesel oil as pilot. The influence of intake pressure and temperature on knock occurrence and the effects of initial swirl ratio on heat release rate, temperature-pressure and emission levels have been investigated in this study. It is shown that an increase in the initial swirl ratio lengthens the delay period for auto-ignition and extends the combustion period while it reduces NOx. There is an optimum value of the initial swirl ratio for a certain mixture intake temperature and pressure conditions that can achieve high thermal efficiency and low NOx emissions while decreases the tendency to knock. Simultaneous increase of intake pressure and initial swirl ratio could be the solution to power loss and knock in dual fuel engine.

Combustion engine. [for air pollution control

Science.gov (United States)

Houseman, J. (Inventor)

1977-01-01

An arrangement for an internal combustion engine is provided in which one or more of the cylinders of the engine are used for generating hydrogen rich gases from hydrocarbon fuels, which gases are then mixed with air and injected into the remaining cylinders to be used as fuel. When heavy load conditions are encountered, hydrocarbon fuel may be mixed with the hydrogen rich gases and air and the mixture is then injected into the remaining cylinders as fuel.

Optimization of combustion chamber geometry for stoichiometric diesel combustion using a micro genetic algorithm

Energy Technology Data Exchange (ETDEWEB)

Park, Sung Wook

2010-11-15

This paper describes the optimization of combustion chamber geometry and engine operating conditions for stoichiometric diesel combustion, targeting lower gross indicated specific fuel consumption. The KIVA code, coupled with a micro genetic algorithm population of nine for each generation was used. The optimization variables were composed of ten variables related to the combustion chamber geometry and engine operating conditions. In addition, an auto mesh generator was developed for generating various kinds of combustion chambers, such as open-crater, re-entrant, deep, and shallow types. In addition, the computational models were validated against the experimental results for a stoichiometric process in terms of the combustion pressure history and emissions. Through the preset optimization, a 35% improvement in the gross indicated that specific fuel consumption was achieved. In addition, the optimization results showed that the optimum engine operating conditions employed a premixed charge compression ignition combustion regime with early injection and a narrow spray included angle. Furthermore, a higher boost pressure was used to prevent fuel film formation. (author)

Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

Energy Technology Data Exchange (ETDEWEB)

Wooldridge, Margaret [Univ. of Michigan, Ann Arbor, MI (United States)

2017-02-24

Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecular structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.

Combustion means for solid fuels

Energy Technology Data Exchange (ETDEWEB)

Murase, D.

1987-09-23

A combustion device for solid fuel, suitable for coal, coke, charcoal, coal-dust briquettes etc., comprising:- a base stand with an opening therein, an imperforate heat resistant holding board locatable to close said opening; a combustion chamber standing on the base stand with the holding board forming the base of the combustion chamber; a wiper arm pivoted for horizontal wiping movement over the upper surface of the holding board; an inlet means at a lower edge of said chamber above the base stand, and/or in a surrounding wall of said chamber, whereby combustion air may enter as exhaust gases leave the combustion chamber; an exhaust pipe for the exhaust gases; generally tubular gas-flow heat-exchange ducting putting the combustion chamber and exhaust pipe into communication; and means capable of moving the holding board into and out of the opening for removal of ash or other residue. The invention can be used for a heating system in a house or in a greenhouse or for a boiler.

Energy efficiency impact of EGR on organizing clean combustion in diesel engines

International Nuclear Information System (INIS)

Divekar, Prasad S.; Chen, Xiang; Tjong, Jimi; Zheng, Ming

2016-01-01

Highlights: • Studied EGR impact on efficiency and emissions of diesel and dual-fuel combustion. • Quantified effectiveness of intake dilution for NOx reduction using EGR. • Identified suitable EGR ranges for mitigating emissions–efficiency trade-off. • Developed careful control of intake dilution and in-cylinder excess ratio. • Enabled ultra-low NOx in both diesel and dual-fuel combustion via EGR control. - Abstract: Exhaust gas recirculation (EGR) is a commonly recognized primary technique for reducing NOx emissions in IC engines. However, depending on the extent of its use, the application of EGR in diesel engines is associated with an increase in smoke emissions and a reduction in thermal efficiency. In this work, empirical investigations and parametric analyses are carried out to assess the impact of EGR in attaining ultra-low NOx emissions while minimizing the smoke and efficiency penalties. Two fuelling strategies are studied, namely diesel-only injection and dual-fuel injection. In the dual-fuel strategy, a high volatility liquid fuel is injected into the intake ports, and a diesel fuel is injected directly into the cylinder. The results suggest that the reduction in NOx can be directly correlated with the intake dilution caused by EGR and the correlation is largely independent of the fuelling strategy, the intake boost, and the engine load level. Simultaneously ultra-low NOx and smoke emissions can be achieved at high intake boost and intake dilution levels in the diesel-only combustion strategy and at high ethanol fractions in the dual-fuel strategy. The efficiency penalty associated with EGR is attributed to two primary factors; the combustion off-phasing and the reduction in combustion efficiency. The combustion off-phasing can be minimized by the closed loop control of the diesel injection timing in both the fuelling strategies, whereas the combustion efficiency can be improved by limiting the intake dilution to moderate levels. The

Combustion in a High-Speed Compression-Ignition Engine

Science.gov (United States)

Rothrock, A M

1933-01-01

An investigation conducted to determine the factors which control the combustion in a high-speed compression-ignition engine is presented. Indicator cards were taken with the Farnboro indicator and analyzed according to the tangent method devised by Schweitzer. The analysis show that in a quiescent combustion chamber increasing the time lag of auto-ignition increases the maximum rate of combustion. Increasing the maximum rate of combustion increases the tendency for detonation to occur. The results show that by increasing the air temperature during injection the start of combustion can be forced to take place during injection and so prevent detonation from occurring. It is shown that the rate of fuel injection does not in itself control the rate of combustion.

Low-cost high-efficiency GDCI engines for low octane fuels

Energy Technology Data Exchange (ETDEWEB)

Kolodziej, Christopher P.; Sellnau, Mark C.

2018-01-09

A GDCI engine has a piston arranged within a cylinder to provide a combustion chamber. According to one embodiment, the GDCI engine operates using a method that includes the steps of supplying a hydrocarbon fuel to the combustion chamber with a research octane number in the range of about 30-65. The hydrocarbon fuel is injected in completely stratified, multiple fuel injections before a start of combustion and supplying a naturally aspirated air charge to the combustion chamber.

Hexaaluminate Combustion Catalysts for Fuel Cell Fuel Reformers

National Research Council Canada - National Science Library

Thomas, Fred S; Campbell, Timothy J; Shaaban, Aly H; Binder, Michael J; Holcomb, Frank H; Knight, James

2004-01-01

.... When heat is produced by combustion of logistics fuel in an open-flame or radiant burner, the rate of hydrogen production in the steam reforming reactor is generally limited by the rate of heat transfer from the burner...

PERFORMANCE AND EMISSION STUDIES ON DI-DIESEL ENGINE FUELED WITH PONGAMIA METHYL ESTER INJECTION AND METHANOL CARBURETION

Directory of Open Access Journals (Sweden)

HARIBABU, N.

2010-03-01

Full Text Available The target of the present study is to clarify ignition characteristics, combustion process and knock limit of methanol premixture in a dual fuel diesel engine, and also to improve the trade-off between NOx and smoke markedly without deteriorating the high engine performance. Experiment was conducted to evaluate the performance and emission characteristics of direct injection diesel engine operating in duel fuel mode using Pongamia methyl ester injection and methanol carburetion. Methanol is introduced into the engine at different throttle openings along with intake air stream by a carburetor which is arranged at bifurcated air inlet. Pongamia methyl ester fuel was supplied to the engine by conventional fuel injection. The experimental results show that exhaust gas temperatures are moderate and there is better reduction of NOx, HC, CO and CO2 at methanol mass flow rate of 16.2 mg/s. Smoke level was observed to be low and comparable. Improved thermal efficiency of the engine was observed.

Characteristics of Flameless Combustion in 3D Highly Porous Reactors under Diesel Injection Conditions

Directory of Open Access Journals (Sweden)

M. Weclas

2013-01-01

Full Text Available The heat release process in a free volume combustion chamber and in porous reactors has been analyzed under Diesel engine-like conditions. The process has been investigated in a wide range of initial pressures and temperatures simulating engine conditions at the moment when fuel injection starts. The resulting pressure history in both porous reactors and in free volumes significantly depends on the initial pressure and temperature. At lower initial temperatures, the process in porous reactors is accelerated. Combustion in a porous reactor is characterized by heat accumulation in the solid phase of the porous structure and results in reduced pressure peaks and lowered combustion temperature. This depends on reactor heat capacity, pore density, specific surface area, pore structure, and heat transport properties. Characteristic modes of a heat release process in a two-dimensional field of initial pressure and temperature have been selected. There are three characteristic regions represented by a single- and multistep oxidation process (with two or three slopes in the reaction curve and characteristic delay time distribution has been selected in five characteristic ranges. There is a clear qualitative similarity of characteristic modes of the heat release process in a free volume and in porous reactors. A quantitative influence of porous reactor features (heat capacity, pore density, pore structure, specific surface area, and fuel distribution in the reactor volume has been clearly indicated.

Gas turbines with complete continuous combustion of the fuels

Energy Technology Data Exchange (ETDEWEB)

Koch, C

1976-10-21

The invention concerns a gas turbine plant with complete continuous combustion of the fuel. The fuel is taken to a gas generator in which the preheated fuel is catalytically converted at high temperature in a fuel mixture using an oxygen carrier. Heating of the fuel takes place in a heat exchanger which is situated in the outlet pipe of the turbine. The efficiency is increased and the emission of noxious gas is kept as low as possible using the heat exchanger as a fuel evaporator and by using part of the waste formed in the combustion chamber to carry oxygen to the gas generator via an outlet pipe.

Numerical simulation of combustion and soot under partially premixed combustion of low-octane gasoline

KAUST Repository

An, Yanzhao

2017-09-23

In-cylinder combustion visualization and engine-out soot particle emissions were investigated in an optical diesel engine fueled with low octane gasoline. Single injection strategy with an early injection timing (−30 CAD aTDC) was employed to achieve partially premixed combustion (PPC) condition. A high-speed color camera was used to record the combustion images for 150 cycles. The regulated emission of carbon dioxide, carbon monoxide, nitrogen oxides and soot mass concentration were measured experimentally. Full cycle engine simulations were performed using CONVERGE™ and the simulation results matched with the experimental results. The in-cylinder soot particle evolution was performed by coupling a reduced toluene reference fuel mechanism including the PAHs formation/oxidation reactions with particulate size mimic model. The results showed that PPC presents typical stratified combustion characteristics, which is significantly different from the conventional diesel spray-driven combustion. The in-cylinder temperature and equivalence ratio overlaid with soot-NO formation regime revealed that PPC operating condition under study mostly avoided the main sooting conditions throughout the entire combustion. The evaluation of temperature distribution showed formaldehyde could be regarded as an indicator for low temperature reactions, while hydroxyl group represents the high temperature reactions. Soot evolution happened during the combustion process, hydroxyl radicals promoted the soot oxidation.