基于Taguchi方法的多段预混压燃发动机喷油策略优化

摘要

在一台4缸柴油机上使用一种低辛烷值G80混合燃料(汽油和柴油的体积比为80∶20)进行了多段预混压燃(MPCI)模式的研究.通过Taguchi试验设计方法和方差分析,解析了喷油时刻、喷油比例等变量对燃烧和排放性能的影响,结果表明:指示燃油消耗率和NOx排放主要受次喷时刻影响,碳烟排放主要受首喷时刻影响.基于上述结果,协同优化喷油时刻和喷油比例,实现了低于原柴油机的NOx、碳烟排放和指示燃油消耗率.通过能量利用分析,发现低传热损失和低排气损失是G80压燃发动机获得高指示热效率的主要原因.%Multiple premixed compression ignition (MPCI)combustion mode was investigated in a four-cylinder diesel engine fueled with a low octane number fuel named G80 (80％ gasoline and 20％ diesel by volume).By applying Taguchi method and analysis of variance (ANOVA),the effect of double injection timings and fuel split ratio on combustion and emissions was studied.The results show that the second injection timing mainly affects the indicated specific fuel consumption (ISFC)and indicated specific nitrogen oxides (ISNOx),while the first injection timing affects the soot emission.The injection timings and split ratio were optimized to achieve lower ISFC,ISNOx and soot emissions simultaneously with G80 fuel compared with diesel.It is found by energy balance analysis that low heat transfer loss and low exhaust loss are the main reason of high thermal efficiency of G80.