喷气对相继增压柴油机切出过程影响研究

摘要

This study performs an air injection test on the switching-out process at the optimum switching-out delay time to improve the transient performance of a diesel engine in the switching-out process of a sequential turbocharg-ing system.The effect of the air injection on the transient performance of the diesel engine is investigated, and a three-dimensional flow field is calculated for the combustion inside the cylinder.The research results show that the transient performance of the diesel engine significantly improved after adopting the air injection technology because the inlet pressure of the diesel engine increased.Furthermore, the speed fluctuation decreased by 42%, and the quantity of the working cycles of the air cylinder reduced by 46%when the stable rotation speed was reached.The emission performance also improved.The smoke emission reduced by approximately 50%,and the hydrocarbon e-mission reduced by approximately 30%.Moreover,the CO emission reduced by approximately 35%.On the con-trary,the NOx emission increased by approximately 20%.%为了改善相继增压系统切出过程中柴油机的瞬态性能,在最佳切出延迟时间时进行了切出过程的喷气试验,研究了喷气对柴油机瞬态性能的影响,并对缸内燃烧进行了三维流场计算.研究结果表明:采用了喷气技术后,由于柴油机的进气压力增加,柴油机瞬态性能得到了明显改善;转速波动减少了42%,达到稳定转速时气缸工作循环数减少了46%.排放性能也得到了改善,烟度排放量减少约50%,HC排放量减少了约30%,CO排放量减少了约35%,但是NOx排放量增加了约20%.