增压中冷柴油机EGR排放特性试验研究

Experimental Investigation on Emission Property of a Supercharged Inter-cooled Diesel Engine

以增压中冷柴油机为研究对象 ,针对其特点设计了废气再循环装置 ,试验研究了不同 EGR率对增压中冷柴油机的动力性、经济性及 NOx、微粒、烟度、HC、CO等排放物的影响规律。研究结果表明 ,增压柴油机借助EGR,可大大降低发动机的 NOx 排放 ,但随着 EGR率的增加 ,柴油机的微粒、烟度、HC、CO排放也相应增加 ,同时对柴油机的扭矩和油耗也造成不利影响。因此 ,在设计增压柴油机 EGR系统时 ,要综合考虑 EGR率对发动机性能和排放的影响规律 ,为各个工况确定最佳 EGR率 ,并采用电控系统保证各个工况的最佳 EGR率。

Exhaust gas recirculation (EGR) is one of the effective technologies to reduce NOx emission from engines. As the pressure in the inlet pipe is greater than that in the outlet pipe, the design of an effective EGR control system for a supercharged inter-cooled diesel engine will be very difficult. A new way to reduce the emission of nitrogen oxide from the diesel engine by EGR is presented in this paper. The effects of different EGR rates on the performances and emissions of the engine were investigated by the engine tests. The results of these tests showed that the NOx emission of the engine could be reduced significantly by EGR, at the same time, however, the emissions of particulates, smoke, HC and CO would increase with the increase of EGR rates in a fixed engine mode. So, the EGR rates of different engine modes should be optimized based on their effects on the engine and an electronically controlled EGR system should be adopted to guarantee the optimum EGR rate.