预喷正时对柴油机燃烧与排放影响的试验研究

通过台架试验,分析对比柴油机各参数随预喷正时的变化,研究多次喷射预喷正时对柴油机燃烧和排放性能的影响。试验表明,预喷正时决定缸内燃烧的放热始点和放热率,影响缸内的燃烧温度、爆发压力、NOx排放和碳烟的生成,预喷正时为20°时,爆发压力最大;预喷正时为35°时,热效率最高,油耗率和烟度最低;预喷正时为45°时,NOx排放最小。综合分析选择预喷正时40°作为折中优化方案,降低发动机油耗和NOx、碳烟排放,同时提高发动机的热效率。

Experimental research on the pilot injection timing effect of combustion and emission of diesel engine

The effect of pilot injection timing in multiple injection on the combustion and emission performance of a diesel engine is studied.Tests show that the pilot injection timing determines the starting point and heat release rate of combustion,and affects the combustion temperature,explosion pressure,NOx and soot emissions.When the pilot injection timing is 20°,the explosion pressure is the largest;the thermal efficiency is highest at pilot injection timing of 35°,and the fuel consumption and smoke are the lowest;NOx emissions are the smallest at the pilot injection timing of 45°.Finally,the pilot injection timing of 40°is a compromise optimization scheme to reduce the fuel consumption and NOx and soot emissions,and improving the engine′s thermal efficiency.