多次喷射对柴油机燃烧与排放影响的试验研究

基于1台高压共轨涡轮增压柴油机,采用不同的预喷正时、预喷油量与后喷正时等,研究了多次喷射对燃烧放热、排放生成与燃油经济性的影响,以实现均质压燃和低温燃烧过程。研究结果表明:随预喷正时提前,缸内峰值压力降低,主燃阶段的滞燃期缩短,NOx和炭烟排放均降低;随预喷油量增加,预喷阶段燃烧的放热率和最大压力升高率增大,NOx和HC排放增大,而PM和CO排放降低;随后喷始点推迟,缸内压力与主放热率峰值差异变小,NOx排放降低,但炭烟排放先增大后逐渐降低。

Influence of Multi-Injection on Combustion and Emission of Diesel Engine

On a 6‐cylinder ,turbocharged ,high‐pressure common rail diesel engine ,the influence of multi‐injection on com‐bustion process ,heat release rate ,emission and fuel economy was studied to realize the homogenous compression ignition and low‐temperature combustion based on the pilot injection timing ,pilot injection mass and post injection timing .The results show that the peak in‐cylinder pressure decreases ,the ignition delay of main combustion shortens ,the NOx and soot emissions reduce with the advance of pilot injection timing .With the increase of pilot injection fuel mass ,the heat release rate and maximum pressure rise of pilot injection combustion increase and the NOx and HC emissions and the PM and CO emissions increase and decrease respectively .As the retarding of post injection timing ,the difference of in‐cylinder pressure and peak heat release rate decreases ,the NOx emission reduces ,but the soot emission first increases and then decreases gradually .