Research On The Influence Of Gasoline/natural Gas Engines Performance

Gasoline/natural gas engine concomitant combustion can make full use of incylinder direct injection liquid fuel evaporation to reduce the temperature inside the cylinder,improve the effect of port injection natural gas on the charging efficiency,and utilize the high octane number,low carbon-hydrogen ratio and low price of natural gas.These advantages can ensure the power of gasoline/natural gas engines,low CO2 emissions and better economics.In this paper,the development of a dual-fuel engine test platform for gasoline/natural gas simultaneous injection in a gasoline-cylinder direct injection and natural gas inlet injection is carried out.The PES(Percentage of Energy Substitution),ignition timing and injection timing of the impact of the combustion process on the gasoline/natural gas engines are studied through bench test.Test results:(1)The torque and thermal efficiency of gasoline/natural gas co-combustion are optimal at PES40 torque and effective thermal efficiency.The effective thermal efficiency of PES40 is 26.78%,which is 7.46% higher than the effective thermal efficiency of PES60.And the effective thermal efficiency of pure gasoline is also increased by about 0.71%.In addition,the cyclical variation of the PES 40 is lower than the pure gasoline mode.(2)As the ignition advance angle increases,the torque and effective thermal efficiency of gasoline/natural gas co-combustion increase.And the ignition timing has a certain influence on SOC,MBF50% and cyclical variation.The ignition timing has little effect on the combustion duration.The ignition timing has a small effect on the burning speed.Compared with the PES,the ignition advance angle has little effect on the cocombustion process of the gasoline/natural gas engine.(3)The injection timing has little effect on the improvement of the parameters of the gasoline/natural gas engines co-combustion process,so the injection timing of the original gasoline engines can be maintained.The three variables of PES,ignition timing and fuel injection time are the PES for the gasoline/natural gas co-combustion from high to small,followed by the ignition timing and the minimum injection timing.This study provides a basis for the subsequent performance improvement of gasoline/natural gas engines.