摘要
以某轻型车用高压共轨柴油机为样机,研究了在小负荷工况条件下,EGR率对柴油机排放、燃烧过程及燃油消耗的影响。试验结果表明:EGR减小了缸内最高燃烧压力及压力峰值,使压力升高率略有增加,降低了瞬时放热率与峰值,延长了燃烧持续期,降低了缸内温度峰值及平均温度。在小负荷工况,EGR可以同时有效改善NOx,HC及CO排放,当EGR阀全开,EGR率为42%时,NOx排放降低了38.7%,HC降低了39.6%,CO排放降低了21.3%;PM排放先随着EGR率增加而减小,EGR率超过某一值后,PM排放增加,整个PM排放曲线呈现"鱼钩"状变化趋势。EGR对小负荷工况燃油耗性能影响不大。
For a vehicle high-pressure common rail diesel engine, the influence of EGR rate on emission performance, combus- tion process and fuel economy at low loads was researched. The results show that, with the EGR device, the maximum com- bustion pressure decreases, the pressure rise rate increases slightly, the combustion duration extends and the in-cylinder tem- perature decreases. At low loads, EGR can improve the NOx, CO and HC emission simultaneously. When the EGR valve opens completely, the EGR rate is 42%. At such time, the NOx, HC and CO emission reduces by 38.7%, 39.6% and 21.3% respectively. Besides, the PM emission first decreases with the increase of EGR rate and then increases when it exceeds a certain value. The whole PM emission curve presents a shape of fishhook. Wh. ile the influence of EGR on fuel economy is small at low loads.
出处
《车用发动机》
北大核心
2010年第4期74-78,共5页
Vehicle Engine
基金
江苏省动力机械清洁能源与应用重点实验室开放基金项目(QK08006)
江苏省科技成果转化专项资金项目(BA2009060)
