天然气的自燃温度较高,要达到其自燃必须采用高压缩比和进气加热,另外一种方法是利用负气门叠开在缸内驻留废气,以减少所需要的进气加热量。本文采用特殊阀的策略,通过与汽油进行对比,发现在相同的发动机负荷下,天然气HCCI需要使用较迟后的气门定时,这导致缸内将截获较少量的废气,因而减小了稀释的效果,使得NOx的排放增加。 Natural gas auto-ignition temperature is higher, in order to achieve its spontaneous combustion must use high compression ratio and intake air heating, the other is to use negative valve stack in the cylinder to park the exhaust gas to reduce the required intake heating. In this paper, a special valve strategy is used to compare with gasoline to find that natural gas HCCI requires later valve timing at the same engine load, which results in a smaller amount of off-gas being captured in the cylinder thus reducing the amount of diluted Effect, making NOx emissions increased.