燃烧室EGR策略下气门升程对CAI燃烧的影响

Effects of Valve Lift on Gasoline CAI Combustion Using Combustion Chamber EGR Strategy

在装备电控液压驱动可变气门机构的单缸试验发动机上,研究了燃烧室EGR策略下气门升程对汽油机可控自燃(CAI)燃烧的影响。研究结果表明:在1 000r/min、过量空气系数为1、气门定时一定的工况下,随着气门升程的增加,EGR率下降,负荷增加,燃烧始点滞后,燃烧持续期增长。在不同气门升程下,CAI燃烧定时区域范围有所差别,气门升程越小所能实现的负荷越小。通过燃烧室EGR策略结合气门升程可拓展CAI燃烧的负荷下限。

On a single-cylinder test system equipped with electro-hydraulic variable valve-train system, the effects of valve lift on gasoline controlled auto ignition （CAI） combustion using combustion chamber EGR strategy were studied. The results show that in conditions of 1 000 r/rain, k= 1 and fixed valve timing, as valve lift increasing, the EGR rate decreases and engine load increases, the firing timing delays and the combustion duration extends. Under varying valve lifts, the CAI combustion region is different. The smaller the valve lift, the smaller the achieved load. By using the combustion chamber EGR strategy combined with varying valve lift, the CAI combustion load lower limit can be expanded.