喷油策略对离子电流信号与HCCI燃烧相位相关性的影响

摘要

Interdependency between ion current characteristics and HCCI combustion phase in different injection strategies were studied in a GDI-HCCI engine assisted with intake-air heating. Results show that cylinder pressure and ion current amplitude decrease and phases of combustion and ion current delay as retarding the injection timing. With increasing fuel injection amount, cylinder pressure and ion current amplitude are increased, and phases of combustion and ion current are advanced. Interdependency between dQmaxand dImin is the highest, CA50 and Imin takes second place and CA10 and Ist is the lowest, even at knock occurrence, dQmax and dImin still maintain higher interdependency. Injection timing has small influence on the interdependency between ion current and HCCI combustion phase. The adjustment of the first fuel injection quantity has significant effect on interdependency between ion current and HCCI combustion phase than that of the second fuel injection quantity. Closed loop control of HCCI combustion phase based on ion current is achieved through adjusting the first fuel injection quantity.%在一台进气辅助加热的缸内直喷HCCI汽油机上,研究了喷油策略对HCCI燃烧离子电流信号与HCCI燃烧相位之间相关性的影响.结果表明:喷油时刻推迟时,缸压和离子电流峰值均减小,燃烧和离子电流特征值相位亦推后；喷油量增加时,缸压和离子电流峰值增大,燃烧和离子电流特征值相位提前；最大燃烧放热率时的曲轴转角dQmax与离子电流差分最小值相位dImin的相关性最高,50％累积放热量对应的曲轴转角CA50与离子电流信号最小值相位Imin次之,10％累积放热量对应的曲轴转角CA10与离子电流起始点相位Ist最低,即使在爆震燃烧发生时,dQmax与dImin依然具有较高的相关性；喷油时刻对离子电流与燃烧相位的相关性影响不大；与二次喷油量相比,首次喷油量的调整对离子电流与燃烧相位的相关性影响更加明显；可通过调整首次喷油量进行基于离子电流的HCCI燃烧相位的闭环控制.