EGR对GDI发动机性能优化潜力的研究

Research on Potential of EGR for GDI Engine Performance Optimization

在成熟标定过的商业化涡轮增压汽油直喷(Gasoline Direct Injection, GDI)发动机上增加一套低压EGR系统,通过对点火参数的优化,在维持动力性不变的前提下探索EGR氛围下废气稀释上限,进而研究废气再循环(EGR)对GDI发动机性能优化的潜力。结果表明:高负荷下循环变动是限制废气稀释上限的主要因素。EGR引入后,各工况废气稀释上限的状态下发动机动力性、经济性得到大幅度提升,NO_(x)以及CO的排放得到有效控制。可以得出结论,动力性边界条件下通过优化点火参数,使废气稀释达到上限,可大幅优化发动机性能。

A set of low-pressure EGR system is added to the commercial turbocharged gasoline direct injection(GDI) engine. By optimizing the ignition parameters, the upper limit of exhaust gas dilution in EGR atmosphere is explored under the premise of maintaining the same power performance, and then the potential of exhaust gas recirculation(EGR) for GDI engine performance optimization is studied. The results show that the cycle variation under high load is the main factor limiting the upper limit of exhaust gas dilution. After the introduction of EGR, the engine power performance and economy are greatly improved under the condition of the upper limit of exhaust gas dilution, and the emissions of NO_(x) and CO are effectively controlled. It can be concluded that the engine performance can be greatly optimized by optimizing the ignition parameters to make the exhaust gas dilution reach the upper limit under the dynamic boundary conditions.