Sample records for carburetion

  1. Carburetant and its Selection%增碳剂及其选用

    惠国栋; 许翔; 张潇; 马斌悍; 邵亮峰; 王利民


    增碳剂在铸造时使用,可大幅度增加废钢用量,减少生铁用量或不用生铁。目前绝大多数增碳剂都适用于电炉熔炼,也有少部分吸收速度特别快的增碳剂用于冲天炉。电炉熔炼的投料方式,应将增碳剂随废钢等炉料一起投放,小剂量的添加可以选择加在铁水表面。但是要避免大批量往铁水里投料,以防止氧化过多而出现增碳效果不明显和铸件碳含量不够的情况。增碳剂的加入量根据其他原材料的配比和含碳量决定。不同种类的铸件,根据需要选择不同型号的增碳剂。增碳剂本身选择纯净的含碳石墨化物质,可降低生铁里过多的杂质,增碳剂选择合适可降低铸件生产成本。目前,国内外对增碳剂及其选用的系统性研究报道比较少,本文对增碳剂和增碳剂的选用进行系统性研究。%Carburetant could significantly increase the amount of scrap during casting, reduce the amount of pig iron or no iron. At present, most carburetant were suitable for smelting furnace, a small number of carburetant with particularly fast absorption rate was fit for the cupola. The feeding mode of furnace was carbon agent added together with the scrap charge. To the small dosage, the adding mode of carburetant was added in the surface. The adding of large quantities of iron into the hot metal should be avoid in order to prevent the occurs of carbon ineffective and the deficiency of casting carbon content. The adding amount of carburetant was based on the ratio of carbon content to other raw materials. The selection of carburetant depended on casting need, the suitable choose could reduce the cost of casting production. The carburetant and its selection were reviewed in this paper.

  2. Comparative Studies on Exhaust Emissions from a Low Heat Rejection Diesel Engine with Carbureted Methanol and Jatropha Oil

    V. V. R. Seshagiri Rao


    Full Text Available Investigations were carried out to control the exhaust emissions from different versions of low heat rejection (LHR diesel engine- LHR-1 engine, LHR-2 engine and LHR-3 with carbureted methanol and crude jatropha oil (CJO. Exhaust emissions of smoke, oxides of nitrogen (NOx and aldehydes from different configurations of the LHR engines were determined at peak load operation of the engine with test fuels with varied injection pressure and compared with pure diesel operation on conventional engine (CE. LHR-1 engine contained a ceramic coated cylinder head engine, LHR-2 engine- Air gap insulated piston with 3-mm air gap with superni (an alloy of nickel crown and air gap insulated liner with superni insert, and LHR-3 engine- ceramic coated cylinder head, air gap insulated piston and air gap insulated liner. Smoke and NOx were measured at peak load operation by AVL Smoke meter and Netel Chromatograph NOx analyzer respectively. Aldehydes which include formaldehyde and acetaldehyde at peak load operation were measured by dinitrophenyle (DNPH method. LHR-3 version of the engine decreased exhaust emissions considerably with carbureted methanol. Smoke emissions decreased by 58�20while NOx emissions decreased by 12�0with LHR-3 engine in comparison with CE with pure diesel operation. The emissions decreased further with increase of injection pressure in different versions of the engine.




    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.

  4. Study of liquid fuel transport in a small carburetted engine in the context of cold-start HC emission control

    Sumit Tewari; T N C Anand; M P Nishikant; R V Ravikrishna


    In the present study, a detailed visualization of the transport of fuel film has been performed in a small carburetted engine with a transparent manifold at the exit of the carburettor. The presence of fuel film is observed significantly on the lower half of the manifold at idling, while at load conditions, the film is found to be distributed all throughout the manifold walls. Quantitative measurement of the fuel film in a specially-designed manifold of square cross section has also been performed using the planar laser-induced fluorescence (PLIF) technique. The measured fuel film thickness is observed to be of the order of 1 mm at idling, and in the range of 0.1 to 0.4 mm over the range of load and speed studied. These engine studies are complemented by experiments conducted in a carburettor rig to study the state of the fuel exiting the carburettor. Laser-based Particle/Droplet Image Analysis (PDIA) technique is used to identify fuel droplets and ligaments and estimate droplet diameters. At a throttle position corresponding to idling, the fuel exiting the carburettor is found to consist of very fine droplets of size less than 15 m and large fuel ligaments associated with length scales of the order of 500 m and higher. For a constant pressure difference across the carburettor, the fuel consists of droplets with an SMD of the order of 30 m. Also, the effect of liquid fuel film on the cold start HC emissions is studied. Based on the understanding obtained from these studies, strategies such as manifold heating and varying carburettor main jet nozzle diameter are implemented. These are observed to reduce emissions under both idling and varying load conditions.

  5. Century-Midas steps slowly into the RV (recreational vehicles) LPG conversion market

    Kincaid, J.


    Midas International will obtain LPG carburetion equipment from Century for installation in up to 20,000 RV. The market for gasoline-powered RV has been depressed since the surge in gasoline prices, and the installation of Century's equipment represents an attempt to attract customers by reducing RV operating costs. According to J. Kincaid (Midas Inst.), propane, besides being cheaper than gasoline, is also cheaper than diesel fuel, despite the better mileage obtained with diesel fuel, because the use of diesel fuel requires the installation of a diesel engine, which is far more expensive than installation of LPG carburetion. Although most of the LPG carburetion manufacturers, with a backlog of orders, did not evince interest in Midas' search for conversion equipment for RV, Century responded, at least partly because Midas also manufactures fleet delivery trucks, which represent a potentially much larger market for LPG conversion and use.

  6. Healthy Functions and Mechanisms of Bamboo-Charcoal Modified Polyesters

    WANG Qi; HE Shu-cai


    In this paper, healthy fuactions and mechanismof bamboo-charcoal modified polyesters arc studied. Theresults show that there are five healthy functionsincorporated effectively in bamboo-charcoal modifiedpolyesters, such as good far-lnfrared radiation, good UVprotection, certain negative ion emission, certain anti-bacteria and good absorption functions. The metal elementsand carburets are mainly responsible for far-infrared,negative ion emission functions. UV prevention functionresults mainly from the carbon elements. The absorbabilityand bacteriostasis functions lie in the porous structures.

  7. Corrosion products study of alcohol by Mossbauer spectroscopy

    Simulated corrosion essays in alcohol is presented and corrosion products of storage tanks (CAPASA) were analyzed. The analysis by Mossbauer absortion and transmission spectroscopy shows the formation of hematite substratum in the rust of the storage tanks of carburetant and burning alcohol. In the sample of corrosion with strong rum shows the formation of lepidocrocite and with destilled water besides of lepidocrocite, magnetite (Fe3 O4) is detected

  8. Future development programs. [for defining the emission problem and developing hardware to reduce pollutant levels

    Jedrziewski, S.


    The emission problem or source points were defined and new materials, hardware, or operational procedures were developed to exercise the trends defined by the data collected. The programs to reduce the emission output of aircraft powerplants were listed. Continued establishment of baseline emissions for various engine models, continued characterization of effect of production tolerances on emissions, carbureted engine development and flight tests, and cylinder cooling/fin design programs were several of the programs investigated.

  9. Analysis of technician-economic viability of vehicles conversion to bio combustible, natural gas -gasoline systems for the Colombian case

    This paper shows from an economical and technical point of view the conversion to bi fuel systems for operation with natural gas. The cost benefits obtained is near 49%. The return internal rate analysis is around 12 months and it is function of distance and vehicles efficiency for carbureted spark ignition engines the loss of power and torque is around 25-30%, which affects vehicle velocity in 15-25%

  10. Fuel cycle analysis based evaluation of the fuel and emissions reduction potential of adapting the hybrid technology to tricycles

    Biona, J.B.M. [Don Bosco Technical College, Mandaluyong City (Philippines); De La Salle University, Center for Engineering and Sustainable Development Research, Manila (Philippines); Culaba, A.B. [De La Salle University, Center for Engineering and Sustainable Development Research, Manila (Philippines); Purvis, M.R.I. [University of Portsmouth, Department of Mechanical Design and Engineering, Portsmouth (United Kingdom)


    A preliminary analysis has been conducted to investigate the fuel use and emissions reduction potential of incorporating hybrid systems to two stroke powered tricycles in Metro Manila. Carbureted and direct injection two stroke engine hybrid systems were investigated and compared with the impact of shifting to four stroke engines. Results showed that hybridized direct injection retrofitted two stroke powered systems would be able to provide far better environmental and fuel reduction benefits than the shift to new four strokes tricycles. It is thus recommended that the development of such technology specifically for tricycles be seriously pursued. (orig.)

  11. Design and emissions of small two- and four-stroke engines



    Contents of this informative publication include: Emissions analysis of small utility engines; Emissions and combustion characteristics from two fuel mixture preparation schemes in a utility engine; The viability of catalyzing a carburetted 50cc two-stroke cycle engine for moped applications; Coefficients of discharge at the apertures of engines; A two-stroke engine model based on advanced simulation of fundamental processes; Analysis of a novel two-stroke engine scavenging arrangement: The neutron engine; and The effects of a heated catalyst on the unsteady gas dynamic process.

  12. Effect of Air Temperature and Relative Humidity at Various Fuel-Air Ratios on Exhaust Emissions on a Per-Mode Basis of an AVCO Lycoming 0-320 Diad Light Aircraft Engine: Volume 1: Results and Plotted Data

    Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempe, E. E., Jr.


    A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions include carburetor lean out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity.

  13. Effect of air temperature and relative humidity at various fuel-air ratios on exhaust emissions on a per-mode basis of an Avco Lycoming 0-320 DIAD light aircraft engine. Volume 2: Individual data points

    Skorobatckyi, M.; Cosgrove, D. V.; Meng, P. R.; Kempke, E. R.


    A carbureted four cylinder air cooled 0-320 DIAD Lycoming aircraft engine was tested to establish the effects of air temperature and humidity at various fuel-air ratios on the exhaust emissions on a per-mode basis. The test conditions included carburetor lean-out at air temperatures of 50, 59, 80, and 100 F at relative humidities of 0, 30, 60, and 80 percent. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased. Even at a fixed fuel-air ratio, the HC emissions increase and the NOx emissions decrease at the higher values of air temperature and humidity. Volume II contains the data taken at each of the individual test points.

  14. Unigas readies for motor fuel surge with supplies from gigantic plant

    Nestled away a short distance from the smog and congestion of Mexico City is a sprawling LP-gas plant from which 72 million gallons of propane are shipped annually. Boasting a storage capacity of 865,000 gal. in 19 tanks, this plant is believed to possess the largest total reserve capacity of any such facility south of the border and in all of Latin America. This paper reports on a tour of the Unigas plant in Ixhuatepec, hosted by general director Carlos Venegas Baeza, which provides insight into three major areas: the operations and plans of one of the largest LP-gas companies in Mexico, the booming market in carburetion, and most noteworthy, the technologically advanced safety/security system that has been installed at this point

  15. Hydrogen engine performance analysis project. Second annual report

    Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.


    Progress in a 3 year research program to evaluate the performance and emission characteristics of hydrogen-fueled internal combustion engines is reported. Fifteen hydrogen engine configurations will be subjected to performance and emissions characterization tests. During the first two years, baseline data for throttled and unthrottled, carburetted and timed hydrogen induction, Pre IVC hydrogen-fueled engine configurations, with and without exhaust gas recirculation (EGR) and water injection, were obtained. These data, along with descriptions of the test engine and its components, the test apparatus, experimental techniques, experiments performed and the results obtained, are given. Analyses of other hydrogen-engine project data are also presented and compared with the results of the present effort. The unthrottled engine vis-a-vis the throttled engine is found, in general, to exhibit higher brake thermal efficiency. The unthrottled engine also yields lower NO/sub x/ emissions, which were found to be a strong function of fuel-air equivalence ratio. (LCL)

  16. Propane vehicles : status, challenges, and opportunities.

    Rood Werpy, M.; Burnham, A.; Bertram, K.; Energy Systems


    Propane as an auto fuel has a high octane value and has key properties required for spark-ignited internal combustion engines. To operate a vehicle on propane as either a dedicated fuel or bi-fuel (i.e., switching between gasoline and propane) vehicle, only a few modifications must be made to the engine. Until recently propane vehicles have commonly used a vapor pressure system that was somewhat similar to a carburetion system, wherein the propane would be vaporized and mixed with combustion air in the intake plenum of the engine. This leads to lower efficiency as more air, rather than fuel, is inducted into the cylinder for combustion (Myers 2009). A newer liquid injection system has become available that injects propane directly into the cylinder, resulting in no mixing penalty because air is not diluted with the gaseous fuel in the intake manifold. Use of a direct propane injection system will improve engine efficiency (Gupta 2009). Other systems include the sequential multi-port fuel injection system and a bi-fuel 'hybrid' sequential propane injection system. Carbureted systems remain in use but mostly for non-road applications. In the United States a closed-loop system is used in after-market conversions. This system incorporates an electronic sensor that provides constant feedback to the fuel controller to allow it to measure precisely the proper air/fuel ratio. A complete conversion system includes a fuel controller, pressure regulator valves, fuel injectors, electronics, fuel tank, and software. A slight power loss is expected in conversion to a vapor pressure system, but power can still be optimized with vehicle modifications of such items as the air/fuel mixture and compression ratios. Cold start issues are eliminated for vapor pressure systems since the air/fuel mixture is gaseous. In light-duty propane vehicles, the fuel tank is typically mounted in the trunk; for medium- and heavy-duty vans and trucks, the tank is located under the body of

  17. Emissions of an AVCO Lycoming 0-320-DIAD air cooled light aircraft engine as a function of fuel-air ratio, timing, and air temperature and humidity

    Meng, P. R.; Skorobatckyi, M.; Cosgrove, D. V.; Kempke, E. E., Jr.


    A carbureted aircraft engine was operated over a range of test conditions to establish the exhaust levels over the EPA seven-mode emissions cycle. Baseline (full rich production limit) exhaust emissions at an induction air temperature of 59 F and near zero relative humidity were 90 percent of the EPA standard for HC, 35 percent for NOx, and 161 percent for CO. Changes in ignition timing around the standard 25 deg BTDC from 30 deg BTDC to 20 deg BTDC had little effect on the exhaust emissions. Retarding the timing to 15 deg BTDC increased both the HC and CO emissions and decreased NOx emissions. HC and CO emissions decreased as the carburetor was leaned out, while NOx emissions increased. The EPA emission standards were marginally achieved at two leanout conditions. Variations in the quantity of cooling air flow over the engine had no effect on exhaust emissions. Temperature-humidity effects at the higher values of air temperature and relative humidity tested indicated that the HC and CO emissions increased significantly, while the NOx emissions decreased.




    Full Text Available In this work a single cylinder two stroke three wheeler SI engine (199.3cc, 6.2 kW and 4500 rpm was used for the test. The engine manifold was altered to run in LPG mode. The gas carburetor was used here to mix the air and LPG thoroughly. Initially the engine was operated with gasoline in carburetor mode for the constant speed of 3000 rpm at different load. Then the engine was operated with LPG mode at the same speed. The performance and emission parameters were compared with gasoline carburetion mode. The maximum brake thermal efficiency with LPG was 22.3% and that with gasoline was 20.3%. The engine could generally operate with lean mixtures with LPG due to its good mixture formation capability. The brake specific fuel consumption decreased for LPG compared to gasoline. The HC and CO levels were lower considerably at LPG mode compared to gasoline operation. High NO and exhaust gas temperature levels were the main problems with LPG.

  19. Multivariate analysis between driving condition and vehicle emission for light duty gasoline vehicles during rush hours

    Qu, Liang; Li, Mengliang; Chen, Dong; Lu, Kaibo; Jin, Taosheng; Xu, Xiaohong


    Fourteen light-duty gasoline vehicles were tested by an OBS-2200 portable emission measurement system (PEMS). Vehicle speed, acceleration and emission rates of HC, CO, NOx and CO2 were recorded during rush hours (7:00-9:00 and 16:30-18:30 local time) in Tianjin, China. The emission factors of HC, CO and NOx for carbureted vehicles were 10, 4, 3 times higher than those with MPI (multi-points injection) and TWC (three-way catalytic converter), respectively. The emission factors of CO2 for carburetor car were 29% lower than those with MPI and TWC. For both types of vehicles, the Pearson correlation coefficients, between speed and CO2 emission in the mode of accelerating as well as between VSP (vehicle specific power) and CO2 emission when VSP > 0, remained relatively high (r > 0.5, p correlation was also found for NOx in carburetor vehicles. Linear trends between emission rates and VSP (bin-averaged data) were observed for NOx and CO2 from MPI vehicles, and HC, NOx and CO2 from carburetor vehicles.

  20. Hydrogen engine performance analysis. First annual report

    Adt, Jr., R. R.; Swain, M. R.; Pappas, J. M.


    Many problems associated with the design and development of hydrogen-air breathing internal combustion engines for automotive applications have been identified by various domestic and foreign researchers. This project addresses the problems identified in the literature, seeks to evaluate potential solutions to these problems, and will obtain and document a design data-base convering the performance, operational and emissions characteristics essential for making rational decisions regarding the selection and design of prototype hydrogen-fueled, airbreathing engines suitable for manufacture for general automotive use. Information is included on the operation, safety, emission, and cost characteristics of hydrogen engines, the selection of a test engine and testing facilities, and experimental results. Baseline data for throttled and unthrottled, carburetted, hydrogen engine configurations with and without exhaust gas recirculation and water injection are presented. In addition to basic data gathering concerning performance and emissions, the test program conducted was formulated to address in detail the two major problems that must be overcome if hydrogen-fueled engines are to become viable: flashback and comparatively high NO/sub x/ emissions at high loads. In addition, the results of other hydrogen engine investigators were adjusted, using accepted methods, in order to make comparisons with the results of the present study. The comparisons revealed no major conflicts. In fact, with a few exceptions, there was found to be very good agreement between the results of the various studies.

  1. [Investigation of emission characteristics for light duty vehicles with a portable emission measurement system].

    Wang, Hai-Kun; Fu, Li-Xin; Zhou, Yu; Lin, Xin; Chen, Ai-Zhong; Ge, Wei-hu; Du, Xuan


    Emission from 7 typical light-duty vehicles under actual driving conditions was monitored using a portable emission measurement system to gather data for characterization of the real world vehicle emission in Shenzhen, including the effects of driving modes on vehicle emission, comparison of fuel consumption based emission factors (g x L(-1) with mileage based emission factors (g x km(-1)), and the average emission factors of the monitored vehicles. The acceleration and deceleration modes accounted for 66.7% of total travel time, 80.3% of traveling distance and 74.6%-79.2% of vehicle emission; the acceleration mode contributed more than other driving modes. The fuel based emission factors were less dependent on the driving speed; they may be utilized in building macro-scale vehicle emission inventory with smaller sensitivity to the vehicle driving conditions. The effect of vehicle technology on vehicle emission was significant; the emission factors of CO, HC and NO(x) of carbureted vehicles were 19.9-20.5, 5.6-26.1 and 1.8-2.0 times the more advanced vehicles of Euro II, respectively. Using the ECE + EUDC driving cycle would not produce the desired real-world emission rates of light duty vehicles in a typical Chinese city. PMID:19143403

  2. Direct Fuel Injection of LPG in Small Two-Stroke Engines

    Yew Heng Teoh


    Full Text Available The commonly used carburetted two-stroke engines in developing countries have high exhaust emission and poor fuel efficiency. To meet more rigid emissions requirements, two-stroke vehicles are typically phase out in favour of four-stroke engines. The problems of ubiquitous legacy two-stroke vehicles remain unsolved by these measures and they are likely to be a major source of transport for many years to come. A number of technologies are available for solving the problems associated with two-stroke engines such as catalytic after-treatment and direct fuel injection (DI. However, these solutions are relatively high cost and have shown only slow market acceptance for applications in developing countries. Research in recent years has demonstrated that direct fuel injection is a well developed and readily deployable solution to existing two-stroke engines. Gaseous fuels such as Liquefied Petroleum Gas (LPG are considered a promising energy source and in many countries provide fuel cost savings. LPG coupled with DI two-stroke technologies, is expected to be clean and cost effective retrofit solution for two-stroke engines. In this research project, direct injection (DI of Liquefied Petroleum Gas (LPG is introduced and tested on a typical two-stroke engine. Results of in cylinder combustion pressure translated to fuel mass fraction burned, engine performance and exhaust emissions are taken and compared for various injection timings from premixed (early injection to fully direct injection mode (late injection. Results show that DI of LPG effectively reduces exhaust hydrocarbon and can substantially improve the fuel economy of two-stroke engines.

  3. On board emission and fuel consumption measurement campaign on petrol-driven passenger cars

    De Vlieger, I.

    Realistic emission and fuel consumption rates of petrol-driven cars were determined by on-the-road experiments in 1995. A validated, in-house developed, on-board measuring system was used. Six three-way catalyst (TWC) cars and one carburetted non-catalyst car were measured. The effects of road type, driving behaviour and cold start on CO, HC and NO x emissions and fuel consumption were analysed. In real traffic situations, emissions for TWC cars were found to be at least 70% lower than for the non-catalyst car. For TWC cars, emissions decreased across the board from city to rural and motorway traffic. Without a catalyst, motorway traffic resulted in the highest NO x emissions. Compared to normal driving, aggressive driving gave emissions which were up to four times higher. Except for NO x, calm driving resulted in lower emissions still. Comparable fuel consumption rates were obtained from normal and calm driving. Those from aggressive driving were higher, by as much as 40% in city traffic. Cold starts resulted in significantly higher CO and HC emission values than hot starts. These differences were less pronounced for NO x. Emissions from TWC cars were higher than generally expected, compared to the European emission limit values (91/441/EEC) and the emission factors used in Flanders and the Netherlands (Klein,1993) for the national emission inventories. Low-emitting cars during the emission test on a chassis dynamometer, as prescribed by the 91/441/EEC directive, did not necessarily give low emissions in real traffic situations.

  4. Dual-fuelling of a direct-injection automotive diesel engine by diesel and compressed natural gas

    Application of Compressed Natural Gas in diesel engines has always been important, especially in the field of automotive engineering. This is due to easy accessibility, better mixing quality and good combustion characteristics of the Compressed Natural Gas fuel. In this study the application of Compressed Natural Gas fuel along with diesel oil in a heavy duty direct-injection automotive diesel engine is experimentally investigated. In order to convert a diesel engine into a diesel-gas one, the so called mixed diesel-gasapproach has been used and for this purpose a carbureted Compressed Natural Gas fuel system has been designed and manufactured. For controlling quantity of Compressed Natural Gas, the gas valve is linked to the diesel fuel injection system by means of a set of rods. Then, the dual-fuel system is adjusted so that, at full load conditions, the quantity of diesel fuel is reduced to 20% and 80% of its equivalent energy is substituted by Compressed Natural Gas fuel. Also injection pressure of pilot jet is increased by 11.4%. Performance and emission tests are conducted under variation of load and speed on both diesel and diesel-gas engines. Results show that, with equal power and torque, the diesel-gas engine has the potential to improve overall engine performance and emission. For example, at rated power and speed, fuel economy increases by 5.48%, the amount of smoke decreases by 78%, amount of CO decreases by 64.3% and mean exhaust gas temperature decreases by 6.4%

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

    Ekenberg, M.


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

  6. Improving the performance and fuel consumption of dual chamber stratified charge spark ignition engines

    Sorenson, S.C.; Pan, S.S.; Bruckbauer, J.J.; Gehrke, G.R.


    A combined experimental and theoretical investigation of the nature of the combustion processes in a dual chamber stratified charge spark ignition engine is described. This work concentrated on understanding the mixing process in the main chamber gases. A specially constructed single cylinder engine was used to both conduct experiments to study mixing effects and to obtain experimental data for the validation of the computer model which was constructed in the theoretical portion of the study. The test procedures are described. Studies were conducted on the effect of fuel injection timing on performance and emissions using the combination of orifice size and prechamber to main chamber flow rate ratio which gave the best overall compromise between emissions and performance. In general, fuel injection gave slightly higher oxides of nitrogen, but considerably lower hydrocarbon and carbon monoxide emissions than the carbureted form of the engine. Experiments with engine intake port redesign to promote swirl mixing indicated a substantial increase in the power output from the engine and, that an equivalent power levels, the nitric oxide emissions are approximately 30% lower with swirl in the main chamber than without swirl. The development of a computer simulation of the combustion process showed that a one-dimensional combustion model can be used to accurately predict trends in engine operation conditions and nitric oxide emissions even though the actual flame in the engine is not completely one-dimensional, and that a simple model for mixing of the main chamber and prechamber intake gases at the start of compression proved adequate to explain the effects of swirl, ignition timing, overall fuel air ratio, volumetric efficiency, and variations in prechamber air fuel ratio and fuel rate percentage on engine power and nitric oxide emissions. (LCL)

  7. Devices to improve the performance of a conventional two-stroke spark ignition engine

    Poola, R.B. [Argonne National Lab., IL (United States); Nagalingam, B.; Gopalakrishnan, K.V. [Indian Inst. of Tech., Madras (India)


    This paper presents research efforts made in three different phases with the objective of improving the fuel economy of and reducing exhaust emissions from conventional, carbureted, two-stroke spark ignition (SI) engines, which are widely employed in two-wheel transportation in India. A review concerning the existing two-stroke engine technology for this application is included. In the first phase, a new scavenging system was developed and tested to reduce the loss of fresh charge through the exhaust port. In die second phase, the following measures were carried out to improve the combustion process: (1) using an in-cylinder catalyst, such as copper, chromium, and nickel, in the form of coating; (2) providing moderate thermal insulation in the combustion chamber, either by depositing thin ceramic material or by metal inserts; (3) developing a high-energy ignition system; and (4) employing high-octane fuel, such as methanol, ethanol, eucalyptus oil, and orange oil, as a blending agent with gasoline. Based on the effectiveness of the above measures, an optimized design was developed in the final phase to achieve improved performance. Test results indicate that with an optimized two-stroke SI engine, the maximum percentage improvement in brake thermal efficiency is about 31%, together with a reduction of 3400 ppm in hydrocarbons (HC) and 3% by volume of carbon monoxide (CO) emissions over the normal engine (at 3 kW, 3000 rpm). Higher cylinder peak pressures (3-5 bar), lower ignition delay (2-4{degrees}CA){degrees} and shorter combustion duration (4-10 {degrees}CA) are obtained. The knock-limited power output is also enhanced by 12.7% at a high compression ratio (CR) of 9:1. The proposed modifications in the optimized design are simple, low-cost and easy to adopt for both production and existing engines.

  8. Gasoline-Related Compounds in Lakes Mead and Mohave, Nevada, 2004-06

    Lico, Michael S.; Johnson, B. Thomas


    The distribution of man-made organic compounds, specifically gasoline-derived compounds, was investigated from 2004 to 2006 in Lakes Mead and Mohave and one of its tributary streams, Las Vegas Wash. Compounds contained in raw gasoline (benzene, toluene, ethylbenzene, xylenes; also known as BTEX compounds) and those produced during combustion of gasoline (polycyclic aromatic hydrocarbon compounds; also known as PAH compounds) were detected at every site sampled in Lakes Mead and Mohave. Water-quality analyses of samples collected during 2004-06 indicate that motorized watercraft are the major source of these organic compounds to the lakes. Concentrations of BTEX increase as the boating season progresses and decrease to less than detectable levels during the winter when few boats are on the water. Volatilization and microbial degradation most likely are the primary removal mechanisms for BTEX compounds in the lakes. Concentrations of BTEX compounds were highest at sampling points near marinas or popular launching areas. Methyl tert-butyl ether (MTBE) was detected during 2004 but concentrations decreased to less than the detection level during the latter part of the study; most likely due to the removal of MTBE from gasoline purchased in California. Distribution of PAH compounds was similar to that of BTEX compounds, in that, concentrations were highest at popular boating areas and lowest in areas where fewer boats traveled. PAH concentrations were highest at Katherine Landing and North Telephone Cove in Lake Mohave where many personal watercraft with carbureted two-stroke engines ply the waters. Lake-bottom sediment is not a sink for PAH as indicated by the low concentrations detected in sediment samples from both lakes. PAH compounds most likely are removed from the lakes by photochemical degradation. PAH compounds in Las Vegas Wash, which drains the greater Las Vegas metropolitan area, were present in relatively high concentrations in sediment from the upstream

  9. Potential of a range extender concept for inner city scooters. An alternative to pure electric mobility?; Potenzial eines REX Konzeptes fuer Stadtscooter. Eine Alternative zur rein elektrischen Mobilitaet?

    Kirchberger, Roland; Schacht, Hans-Juergen; Eichlseder, Helmut [Technische Univ. Graz (Austria). Inst. fuer Verbrennungskraftmaschinen und Thermodynamik


    Nowadays the scooter market class L1e (<50cm{sup 3}, speed limited to 45km/h) is dominated by low-cost two-stroke carburetted engines. With the implementation of the new EURO 3 regulation, obligatory for new type approval by 2014 and for all newly licenced types by 2015, the market will suffer the loss of these low cost vehicles due to the requested durability of exhaust gas after treatment systems. More complex drive units, like lambda controlled 4-stroke engines or 2-stroke engines with direct injection will have to follow. Pure electric scooters pose a further possibility to fill the resulting gap. A significant cost increase is common to all of these approaches. Necessary additional system components will cause the increase for ICE variants, whereas battery costs are responsible for the electric variant. The goal is to find an alternative to be able to comply with the requirements of emission legislation and to keep the product price as low as possible at the same time. A technological comparison of different approaches revealed the serial hybrid variant as most promising. The evaluated system and the derived concept consist of a combination of an electric scooter with a halved battery size (cost reduction) and a Range Extender with the possibility to extend, if necessary, the range to the standard of conventional ICE variants. This alternative is able to offer electro-mobility and therewith local zero emissions without the immanent ''range anxiety'' usually caused by pure electric vehicles [8]. Having defined the system layout as plug-in hybrid-electric vehicle (PHEV) and checked the characteristics of single components in numerous preliminary investigations, a longitudinal backward simulation was carried out. It permits the testing of different operational strategies in combination with a subsequent evaluation of the fuel consumption reduction potential [16]. A packaging analysis could verify the constructive feasibility. Finally, the

  10. Efeito do CO2 e etileno no período de dormência de minitubérculos de batata cv. Macaca Effect of CO2 and ethylene on the dormancy period of potato cv. Macaca minitubers

    Dilson Antônio Bisognin


    Full Text Available Avaliou-se o efeito do CO2 e etileno no período de dormência de minitubérculos de batata da cultivar Macaca produzidos em telado durante duas safras. Imediatamente após a colheita, os minitubérculos foram submetidos aos tratamentos de abafamento com etileno (1000 mL L-1 por 72 h; CO2 (20% por 72 h; carbureto de cálcio (200 g m-3 por 72 h; e 1-metilciclopropeno (1-MCP (1mL L-1 por 24 h (apenas na safrinha; e imersão em solução de ethephon (840 mg L-1 por 5 s. A testemunha não recebeu nenhum tratamento. O delineamento experimental foi um fatorial (safras x tratamentos no inteiramente casualizado, com quatro repetições de 15 minitubérculos. Em intervalos semanais foram avaliadas a respiração e a produção de etileno. A cada 15 dias avaliou-se o número de brotos e a percentagem de tubérculos brotados, calculando-se a área abaixo da curva de progressão. Os minitubérculos produzidos durante a safra, comparados com os da safrinha, apresentaram menor período de dormência e aumentaram a taxa respiratória durante o período de armazenamento, claramente relacionados com a brotação dos minitubérculos. O CO2 e etileno não promoveram o encurtamento, enquanto que o 1-MCP prolongou o período de dormência de minitubérculos de batata cv. Macaca.The effect of CO2 and ethylene treatments were evaluated on the dormancy period of 'Macaca' minitubers produced in greenhouse during two growing seasons. Minitubers were treated soon after harvesting. The treatments were suffocation with ethylene (1000 mL L-1 during 72 h; CO2 (20 % during 72 h; calcium carburet (200 g m-3 during 72 h; and 1-methylcyclopropene (1-MCP (1 mL L-1 during 24 h (only for second season; and immersion with 2-cloroetil fosfonic acid (840 mg L-1 during 5 s. Control minitubers did not receive any treatment. The experiment was a factorial (seasons x treatments in a randomized design, with four replications of 15 minitubers. Respiration and ethylene production were

  11. Evaluating the effect of methanol-unleaded gasoline blends on SI engine performance

    B Sabahi


    Full Text Available Introduction: Today, all kinds of vehicle engines work with fossil fuels. The limited fossil fuel resources and the negative effects of their consumption on the environment have led researchers to focus on clean, renewable and sustainable energy systems. In all of the fuels being considered as an alternativefor gasoline, methanol is one of the more promising ones and it has experienced major research and development. Methanol can be obtained from many sources, both fossil and renewable; these include coal, natural gas, food industry and municipal waste, wood and agricultural waste. In this study, the effect of using methanol–unleaded gasoline blends on engine performance characteristics has been experimentally investigated. The main objective of the study was to determine engine performance parameters using unleaded gasoline and methanol-unleaded gasoline blends at various engine speeds and loads, and finally achieving an optimal blend of unleaded gasoline and methanol. Materials and Methods: The experimental apparatus consists of an engine test bed with a hydraulic dynamometer which is coupled with a four cylinder, four-stroke, spark ignition engine that is equipped with the carbureted fuel system. The engine has a cylinder bore of 81.5 mm, a stroke of 82.5 mm, and a compression ratio of 7.5:1 with maximum power output of 41.8 kW. The engine speed was monitored continuously by a tachometer, and the engine torque was measured with a hydraulic dynamometer. Fuel consumption was measured by using a calibrated burette (50cc and a stopwatch with an accuracy of 0.01s. In all tests, the cooling water temperature was kept at 82±3˚C. The test room temperature was kept at 29±3˚C during performing the tests. The experiments were performed with three replications. The factors in the experiments were four methanol- unleaded gasoline blends (M0, M10, M20 and M30 and six engine speeds (2000, 2500. 3000, 3500, 4000 and 4500 rpm. Methanol with a purity of