Simulation of Timing-Sequential Regionalized Combustion of a Diesel Engine Based on Post Injection Strategy

According to preceding researches,combustion of post injection fuel can be seen as a kind of regionalized combustion based on timing sequence. In order to understand this kind of regionalized combustion deeply,simulations were carried out on combustion of a common rail diesel engine under post injection mode. The results indicate that much oxygen moves into injection-cone region guided by tumble flow in the interim period between main injection and post injection and forms a rich-oxygen region,and then post injection fuel is injected into this region. So regionalized combustion is realized and post injection fuel burns more completely,which results in a remarkable reduction of soot. In order to organize the best regionalized combustion,the interval between main injection and post injection should be as small as possible on the premise that oxygen is enough.