通过对汽油机可变截面增压(VGT)系统和废气再循环(EGR)系统进行匹配数值模拟,研究VGT增压系统对汽油机动力性和燃油经济性等性能的影响.为了最大程度地提高汽油机的动力性能并且有效降低污染物排放,研究VGT和EGR匹配对汽油机主要性能的影响.研究结果表明:低速低负荷采用一定量的EGR,可提高燃油经济性,但EGR过高,会破坏燃油经济性,最大EGR率可达51％；当中高速中高负荷采用EGR率为0时,燃油经济性提高；若增加EGR率,则会降低燃油经济性,EGR率过大还会导致动力不足.%Through the matching numerical simulation of the variable geometry turbocharger (VGT) system and the exhaust gas recirculation (EGR) system, the effects of VGT turbocharging system on the power and the fuel economy of gasoline engine were researched. In order to realize the goal for imporoving the maximum power and reducing the maximum emissions of gasoline engine, the effects of matching VGT and EGR to the main performance of gasoline engine were studied. The results show that the fuel economy is improved by using a certain amount of EGR rate in the low speed and load, but it is reduced in high EGR rate, and the largest EGR rate achieves 51%. When EGR rate is 0 in high speed and high load, the fuel economy can be improved and it will sacrifice the fuel economy if EGR rate is too large and the power can not reach the target value.
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