燃料辅助喷射对柴油机起动着火及排放的影响

为了研究辅助燃料对柴油机起动工况着火及排放的影响规律,在柴油机起动过程中,向进气道内分别喷射不同浓度的乙醚和C3H8进行了试验。试验结果表明:辅助喷射适当种类的燃料,可实现诱导、促进着火并改善燃烧的目的。辅助燃料除应具备良好的挥发性外,其着火性也是改善起动性能的重要因素。进气道喷射C3H8会抑制起动着火性,随喷射浓度的增加,燃烧恶化,HC排放升高;喷射适量浓度乙醚,可以促进起动过程着火,完全消除起动工况失火和不完全燃烧循环,在降低HC排放的同时,减少PM排放50%以上。

Effect of Fuel Auxiliary Injection on Ignition and Exhaust Emission of Diesel Engine during Starting

In order to study the effect of auxiliary fuel on the ignition and exhaust emission of diesel engine during starting,the experiments were carried out by injecting different volume fraction of aether and C3H8 into inlet port individually under starting conditions.The results indicate that proper auxiliary fuel injection can induce ignition and improve the combustion performance.Besides the good volatility,the ignitability of auxiliary fuel is also one of the important factors which can improve the startability.The C3H8 injection has negative effect to the ignitability of start.With the increase of volume fraction of injected C3H8,the combustion goes bad and the HC emission increases.To inject proper volume fraction of aether can improve the ignition during starting,entirely eliminate misfiring and incomplete combustion cycles and reduce PM by more than 50 per cent when the HC emission is reduced.