汽油发动机怠速工况富氧燃烧的研究

利用不同进气氧体积分数,实现汽油机富氧燃烧。氧体积分数分别为21.1%,22.6%,25.5%条件下,试验研究了在怠速工况下汽油发动机燃烧特性和排放特性。研究结果表明:在汽油机中怠速工况下,随着氧体积分数的增加,缸压、瞬时放热率明显增大,峰值相位出现时刻提前,累积放热量明显增大;进气中氧浓度加大,循环波动率下降,提高了发动机缸内燃烧的稳定性,燃油消耗量基本保持不变;在怠速工况下实现富氧燃烧,可以大大降低THC和CO的排放,NO2的排放增加,但增加的幅度处于较低的水平。

Oxygen-Enriched Combustion in Idling Condition of Gasoline Engine

Oxygen-enriched combustion is realized on a gasoline engine by controlling the different intake oxygen volume fraction.The characteristics of combustion and emission of a gasoline engine in the idling condition are studied by controlling the oxygen volume fraction at 21.1%,22.6%,25.5% O2.The research results show that with the increment of oxygen volume fraction in idling condition,the in-cylinder pressure and combustion heat release rate increase obviously;the time when the angle of peak appears advances and cumulative heat release increases sharply.As the intake oxygen density increases,the cycle-to-cycle variation decreases,and the combustion stability of the gasoline engine is improved;meanwhile,fuel consumptions are almost invariable.Realizing oxygen-enriched combustion in idling condition,the emission of THC and CO reduces largely and emission of NO2 increases,but the increment is at a low level.