过量空气系数对HCCI汽油机燃烧特性的影响

Effect of Lambda on Combustion Characteristics of an HCCI Gasoline Engine

在一台Ricardo Hydra单缸四气门汽油机上,利用气门重叠负角方法实现了均质充量压缩着火(HCCI)燃烧,并通过试验研究了过量空气系数对HCCI汽油机燃烧特性的影响.研究结果表明,在相同的转速和气门相位角下,随着过量空气系数的增加,平均指示压力减小,缸内残余废气率也减小,但燃油消耗率的变化趋势与转速有关.在大多数工况下,过量空气系数为1.05时,HCCI发动机的着火时刻最早,燃烧持续期最短.过量空气系数对循环波动的影响与转速和气门相位角有关.随着转速的增加,循环波动增大.

Homogeneous charge compression ignition （HCCI） combustion was achieved on a Ricardo Hydra four-stroke single cylinder port fuel injection gasoline engine through negative overlap. The effect of lambda on HCCI combustion characteristics was also investigated. The results show that when lambda increases at the same engine speed and under the same valve timing conditions, indicated mean effective pressure pi and residuals decrease, but indicated specific fuel onnsumption is related to engine speeds. In most cases, the earliest ignition takes place and the shortest combustion duration occurs when lambda is 1.05. The effect of lambda on coefficient of variation （COV） of pi is also dependent on valve timing and engine speed. COV of pi inereases with engine speed.