废气再循环对天然气发动机性能影响研究  

Influence of EGR on CNG Engine Performance

作　　者：杨立平 马修真[1] 宋恩哲[1] 李君[2] 李学民[1] 

机构地区：[1]哈尔滨工程大学动力与能源工程学院,黑龙江哈尔滨150001 [2]吉林大学汽车工程学院,吉林长春130025

出　　处：《车用发动机》2010年第2期31-34,共4页Vehicle Engine

基　　金：国家"八六三"重点基础研究发展规划资助项目(2006AA11A1B1);哈尔滨市科技攻关计划项目(2009AA2AG060)

摘　　要：利用1台增压中冷天然气发动机，在2840r／min，75％和50％负荷、过量空气系数屯为1．1～1．3稀混合气条件下研究了EGR对天然气发动机性能影响。结果表明：不同负荷和Фa下，随着EGR增加，NOx排放迅速降低，与单纯采用空气稀释相比，稀混合气加EGR联合稀释的方式更具降低NOx排放的潜力，75％负荷、Фa=1．3发动机达到稳定运行界限时（循环变动系数为10％）NOx排放降低到0．3g／（kW·h），而单纯采用空气稀释时只能降低到1．92g／（kW·h）；当EGR率小于10％时，随着EGR增加，HC和CO排放缓慢增加，有效热效率缓慢下降，当EGR率超过10％后，HC，CO排放增加和有效热效率下降的速度都加快。小负荷时产生的NOx排放较少，且达到相同NOx排放目标值时所需的EGR量也较少，但是会产生较高的HC和CO排放及较低的热效率。For a turbocharged inter cooling CNG engine, the influence of EGR on engine performance was researched at the speed of 2 840 r/rain with 75% and 50% load respectively when the excess air coefficient was 1.1-1.3. The results show that the NOx emission decreases with the increase of EGR at different loads and excess coefficients. Compared with only lean burn technology, the learn burn technology with EGR has greater potential to reduce NOx emission. At 75% load when he excess air coefficient is 1.3, the NOx emission can be reduced to 0.3 g/（kW · h）when the engine reaches the limit of steady operation, that is to say, the cycle-to cycle variation coefficient is 10%. While with only lean burn technology, the NOx emission can only be decreased to 1.92 g/（kW · h）. When the EGR is smaller than 10%, the HC and CO emissions increase slowly and the effective thermal efficiency decreases slowly with the increase of EGR. However, when the EGR is beyond 10%, the HC and CO emissions increase rapidly and the effective thermal efficiency decreases rapidly. At low load, the NOx emission is less , the required EGR for the same NO, emission is also smaller, but the higher HC and CO emission and lower thermal efficiency occurs.

关 键 词：天然气发动机 废气再循环 排放控制 热效率 

分 类 号：TK437[动力工程及工程热物理—动力机械及工程]