What is it about?
The results of experimental studies on load characteristics (3000 rpm) of a two-stroke engine 1D 8.7 / 8.2 with spark ignition, crankcase scavenging, air cooling and direct fuel injection have been considered in the paper. Changing the design of combustion chamber and spray nozzle allowed to accomplish different patterns of fuel and air charge formation. Forming lean fuel-air mixture (1.5 > λcyl > 1.0) is carried out at fixed composition in the clearance volume. Forming rich fuel-air mixture (1.0 > λ > 0.8) in the spark plug area with the air at λcyl < 5 near the clearance volume walls enables to generate a stratified fuel-air charge. Forming lean fuel-air mixture (1.5 > λ > 1.0) in the spark plug area with the air λcyl < 5 near the clearance volume walls enables to generate a stratified lean fuel-air charge. It has been revealed that generating the stratified lean fuel-air charge allows reducing fuel consumption by 16–27 % and to reduce CO and CH emissions with exhaust gases up to 14 times in comparison with the generation of lean fuel-air charge.
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Why is it important?
The aim of the research is to determine the influence of the working processes with lean fuel-air mixture in the cylinder on the indicators of power, efficiency and environment-oriented operation of the engine with spark ignition and direct-injection fuel and the choice of the most efficient process.
Perspectives
According to the experimental data, it is determined that the most effective work process is the generation of a stratified lean fuel-air charge in comparison with the lean fuel-air charge and the stratified fuel-air charge. Therefore, a more detailed study of the special features and the work process with stratified lean fuel-air charge is appropriate for further research.
Volodymyr Korohodskyi
Kharkiv National Automobile and Highway University
The study investigates how different fuel-air charge (FAC) patterns affect the performance, fuel economy, and emissions of a two-stroke 1D 8.7/8.2 spark-ignition (SI) engine equipped with direct fuel injection (DIF). Three combustion strategies were tested: LFAC – homogeneous lean fuel-air charge, SFAC – stratified rich core with air near chamber walls, SLFAC – stratified lean core with air near walls. Methodology: Experiments were conducted at 3000 rpm under various load conditions on a test bench with ISO-compliant performance and emissions measurement systems. Each FAC pattern was implemented using different nozzle designs and combustion chamber geometries. Key parameters, including brake mean effective pressure (bmep), brake specific fuel consumption (bsfc), exhaust gas temperature, and concentrations of CO and CH in exhaust gases, were recorded. Conclusions: The stratified lean fuel-air charge (SLFAC) provides the most efficient and environmentally favorable combustion process in the tested two-stroke SI engine. Its advantages stem from improved mixture formation, reduced heat losses to chamber walls, better gas exchange, and optimized combustion phasing. Further research into SLFAC’s specific mechanisms and optimization is recommended.
Volodymyr Korohodskyi
Kharkiv National Automobile and Highway University
Read the Original
This page is a summary of: Influence of the stratified fuel-air charge pattern on economic and environmental indicators of a two-stroke engine with spark ignition, January 2021, American Institute of Physics,
DOI: 10.1063/5.0068466.
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