利用机内和后处理措施改善柴油机的排放特性

采用低排放缩口型燃烧室且推迟供油提前角的方法降低轻型车用柴油机的NOx排放，同时采用氧化型催化后处理装置进一步降低CO、HC排放。试验结果表明，采用催化剂含量不同的氧化催化装置后，对柴油机排放净化效果不同。结合机内控制NOx排放的技术措施，采用氧化型后处理方式可明显改善车用柴油机的排放特性。氧化型催化转换装置的转换率与催化剂的含量有关，对一定结构催化转换装置存在最佳的催化剂含量，而且其转换率随空燃比的变化而变化。

Emission Improvement of Vehicle Diesel Engine by Fuel Injection Timing and After-treatment

In this paper, the fuel supply advance angle was decreased to reduce NO x emission of the light-duty diesel engine with low emission combustion chambers. At the same time, the oxidation catalytic converter was also used to reduce CO and HC emission. The experiment results showed that the conversion efficiency was different by using different catalyst loading in the oxidation catalytic converters and there were an optimum catalyst loading of oxidation catalytic converter. This kind of oxidation catalytic converter is very effective to decrease emission level with control NO x level in engine. The conversion efficiency varies with the catalyst loading and air-fuel ratio, moreover, every oxidation catalytic converter has its optimum catalyst loading.