直喷增压汽油机喷油器匹配及控制策略研究

Research on Matching Experiment of Injector and Control Strategy for Turbocharged Gasoline Direct Injection Engine

针对一款国Ⅵ排放直喷增压汽油机电控系统的匹配,进行了不同喷油器的选型测试,对比研究了不同喷油器喷雾特征和燃烧室形状对发动机排放及油耗的影响。在此基础上,对比研究了喷油时刻、喷油比例以及喷油压力等参数对碳烟排放的影响。结果表明:A型喷油器与平顶活塞的匹配组合最佳;不仅碳烟排放低,而且燃烧速率快,燃烧稳定性好;当采用多次喷油模式时,随着第一次喷油时刻的推迟,碳烟排放有减低趋势。但随着第二次和第三次喷油时刻的推迟,碳烟排放反而呈增大趋势;而当增加第三次喷油比例时,碳烟排放会明显增加;部分负荷工况,采用更高的喷油压力对碳烟排放并无明显改善。而在外特性工况,采用更高的喷油压力时,碳烟排放改善效果明显,同时THC也有一定程度降低。

In order to match electric control system of one type turbocharged gasoline direct injection(GDI) engine for National Stage Ⅵ emissions, experiments with different injector were test. Here, the effects of different injector spray characteristics and combustion chamber on engine emission and fuel consumption were compared. And then the effects of fuel injection time, injection ratio and injection pressure on soot emission were investigated. The results show that the combination of injector A and flat piston is the best. It not only has lower soot emissions, but also increases the combustion rate. When the pattern of multiple injections is used, there is a tendency to reduce soot emissions as the first time of injection is delayed. But with the second and third time of injection delay, soot emissions will be increased. Especially, when the rate of third injection is increased, the soot emissions will increase significantly. At part load condition, a higher fuel injection pressure has no significant improvement in soot emissions. While at full load condition, a higher fuel injection pressure was better for soot emissions. And there is also a slight improvement in hydrocarbon emissions.