进气温度和湿度对汽油机怠速排放的影响

INFLUENCE OF INTAKE AIR TEMPERATURE AND HUMIDITY ON EMISSION PERFORMANCE OF GASOLINE ENGINE AT IDLE SPEED

本文分析了电控汽油发动机在正常怠速时尾气排放分别与进气温度和湿度的变化关系,试验结果表明,进气湿度在42±2%的相对稳定的范围,进气温度从0℃到40℃间隔10℃的增加过程中,HC、NOX和CO三种排放污染物都是先减少后增加。HC在进气温度为0℃时排放最多,20℃时排放量最少,进气温度从0℃升高到20℃时,HC排放下降了7.9%;NOX在进气温度为40℃时排放量最多,20℃时排放量最少,进气温度从20℃升高到40℃时,NOX排放上升了5.1%;CO在进气温度为0℃排放最多,20℃和30℃时排放最低。汽油机进气温度和其他运行参数保持不变时,进气相对湿度从40%逐步增加到85%时,NOX的怠速排放下降明显,HC和CO的怠速排放都有所上升,试验所用的帕萨特B5发动机进气湿度从40%上升到85%时,NOX的怠速排放下降了14.4%,而HC和CO的排放分别上升了4.6%和4.2%。

This paper analyses the change in emissions of EFI gasoline engines with intake air temperature and humidity at normal i- dle. The test showed HC, NOx and CO three emissions decreased first and then increased when intake air temperature increased from 0~C to 40~C with 10~C interval increased as the intake air humidity stayed at 42 ＋ 2% relative stable range. The engine exhausted most and least HC emissions with the inlet temperature was 0~C and 20~C respectively. While intake air temperature increased from O^C to 20~C, the HC emissions decreased by 7.9%. NOx peak and minimal emission reached with the inlet temperature was 40~C and 20~C respectively. NOx emissions increased by 5.1% while the intake air temperature increase from 20~C to 40~C. CO peak emission appeared with the inlet temperature was 0~C while minimal emission appeared with the inlet temperature was 20~C and 30~C. NOx sig- nificantly decreased when the intake air humidity gradually increased from 40% to 85%, while the HC and CO slightly increased when the intake air temperature and other operating parameters didnt change. NOx emission of Passat 135 engine used in the test decreased by 14.4%, while HC and CO emissions increase by 4.6% and 4.2% respectively.