中文摘要：

对一台改制稀燃汽油机分别采用EGR、LNT催化器及EGR耦合LNT系统对该发动机的NOx排放控制效果进行对比分析。结果发现，单独采用EGR时，当EGR率超过30％以后发动机开始出现工况运转不稳的状况，并且当EGR率为15％至30％之间时，可以对NOx的排放起到明显的降低效果；单独采用LNT催化器时，LNT催化器的NOx转化效率可以稳定地保持在89．3％左右；采用EGR耦合LNT系统时，EGR率为10％至20％之间时，两种技术的耦合使得系统总体的NOx排放控制效果最佳。相比于单独采用EGR和单独采用LNT，EGR耦合LNT系统具有同时实现低NO。排放及低成本的潜力。

英文摘要：

A comparative analysis of the effect of sole EGR, sole LNT and EGR-LNT coupling system on NOx emission control is conducted in a lean-burn gasoline engine. Results show that, in the case of sole EGR, unstable operation do not occur until EGR rate is higher than 30%, and there is a significant effect of NOx reduction when EGR rate ranges between 15% and 30%. In the case of sole LNT, its NOx conversion efficiency can be stably maintained at about 89.3%. In the case of EGR-LNT coupling system, the coupling of that two technologies can make the system achieve the best effect of NOx reduction when EGR ranges between 10% and 20%. Compared with sole EGR and sole LNT, EGR-LNT coupling system has the potential to achieve both low NOx emission and low cost.