边界参数对汽油压燃(GCI)小负荷工况燃烧和排放的影响

Simulation of Gasoline Compression Ignition Model Under Low Load Condition

针对小负荷工况下汽油压燃(GCI)燃烧模式燃烧波动和排放超标等问题,建立了单缸四冲程汽油压燃发动机仿真模型,并借助CONVERGE模拟平台,对压缩比、缸内初始涡流比、喷油压力等因素进行了仿真分析。结果表明:压缩比为16.5时,峰值缸压出现在上止点之后,可实现小负荷稳定燃烧。缸内初始涡流比为1.5时,峰值缸内平均温度最高,且排放得到进一步优化。喷油压力为20MPa时,能达到较高的热效率和较低的排放。研究结果为实现小负荷工况稳定燃烧,拓展负荷范围提供了理论基础。

To solve the problems of combustion fluctuation and excessive emission in the gasoline compression ignition(GCI)combustion mode under small load conditions,a single-cylinder four-stroke diesel engine simulation model was established,and the compression ratio,cylinder initial swirl ratio,injection pressure and other factors were simulated by ulitizing the CONVERGE simulation platform.The results show that the peak cylinder pressure appears at the top and bottom points when the compression ratio is 16.5,and the small load stable combustion can be realized.When the initial swirl ratio is 1.5,the peak cylinder average temperature is the highest,and the emission is further optimized.When the injection pressure is 20MPa,higher thermal efficiency and lower emission can be achieved.The research results provide a theoretical basis for the realization of stable combustion under small load conditions and expanding the load range.