进气湿度对电控汽油机怠速排放特性的影响

Influence of intake air humidity on emission performance of EFI gasoline engine at idle speed

本文分析了两台电控汽油机在正常怠速时尾气排放随进气湿度的变化关系。试验结果表明,汽油机进气温度和其他运行参数保持不变时,进气湿度对两台电控汽油机的怠速排放的影响有共同特点,即进气相对湿度从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。其中,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%;另一台丰田2JZ―GE型发动机由于排放超标,只做定性分析,结果表明进气湿度对其怠速排放的影响特点与帕萨特发动机的相同。

This paper analyses the change in emissions of two EFI gasoline engines with intake air humidity at normal idle.The test shows the influence of intake air humidity on emission of two EFI gasoline engines has common features when the intake air temperature and other operating parameters don’ t change.That is NOx significantly decreases when the intake air humidity gradually increases from 40% to 85%,while the HC and CO slightly increases.Among them,NOx emission of Passat B5 engine used in the test decreases by 14.4%,while HC and CO emissions increases by 4.6% and 4.2% respectively.The idle emission of Toyota 2JZ-GE engine is qualitatively studied due to its excessive emissions,which shows the influence of intake air humidity on idle emission has the same characteristics.