喷油定时对GDI汽油机燃用含水乙醇汽油的燃烧和颗粒排放的影响

Influence of Injection Timing on Combustion and Particulate Emission of GDI Engine Fueled with Hydrous Ethanol Gasoline

在1台2.0 L直列4缸GDI汽油机上,分别燃用汽油、含水乙醇汽油E10W、E20W,保持转速和平均指示压力不变,在不同喷油定时下分析汽油、E10W、E20W的燃烧特性和颗粒物排放特性。结果表明:随着喷油定时的推迟,缸内压力、放热率和缸内平均温度三者峰值均呈现下降趋势,且放热率和缸内平均温度峰值位置推迟。燃用含水乙醇汽油E20W的CO和THC排放与燃用汽油相差不大,燃用E10W的CO和THC排放均比燃用汽油高;燃用E10W和E20W的NO_(x)排放量比燃用汽油高。燃用E10W和E20W排放的颗粒物数浓度相对燃用汽油有较大幅度的降低;三种燃料颗粒物总数浓度、核态和积聚态颗粒物均在喷油时刻为300°BTDC时达到最小值;随着含水乙醇含量的增加,颗粒物粒径的最大值呈减小趋势,且积聚态颗粒物数浓度也降低。

The combustion and particulate matter emission characteristics of gasoline and E10W and E20W hydrous ethanol gasoline were analyzed at different injection timings on a 2.0 L inline 4-cylinder GDI engine at the same speed and average indicated pressure.The results show that the peak values of in-cylinder pressure,heat release rate and in-cylinder average temperature all show a downward trend and the peak positions of the two latter ones delay with the delay of injection timing.Compared with gasoline,the CO and THC emissions of E20W almost keep the same and those of E10W have an increase,the NO_(x) emissions of E10W and E20W also increase,but particulate matter emissions of both have a significant reduction.the total particulate number,nuclear and accumulated particulate matter of the three fuels all reach the minimum at 300°BTDC.With the increase of hydrous ethanol content,the maximum particle size shows a drop trend and the number of aggregated particles also decreases.