직접분사식 가솔린엔진에서 Cooled HP-EGR 시스템 적용에 따른 북미 시험모드 별 차량 연비개선 포텐셜에 관한 연구

다국어 초록 (Multilingual Abstract)

This paper focuses on the vehicle test result of the US fuel economy test cycles such as FTP75, HWY and US06 with Cooled HP-EGR system on gasoline direct injection(GDI) engine. In general, with EGR system, the mixing exhaust gas with clean air reduces the oxygen concentration in the cylinder charge and increase the heat capacity of the charge mixture. As a result, the combustion temperature drops which is known to improve knocking limit and fuel economy. In this study, 2.4 liters GDI production vehicle was reworked with electrical controlled EGR valve and high efficiency EGR cooler used in diesel serial production. The control algorithm of Cooled HP-EGR system was realized by model based development using SDA-iRPT(internal rapid prototyping) tool from Continental Automotive System. In experiment result, we confirmed that the spark timing was more advanced without knocking and manifold pressure was increased in all cases with EGR system. Furthermore, a positive potential of fuel economy improvement on FTP mode, US06 mode have been shown with EGR system but not for HWY mode where the engine load is quite low and the spark advance is already optimized. Consequently, the fuel economy was increased by maximum 3.3% on FTP mode, 2.7% on US06 mode and decreased by 0.3% on HWY mode respectively with EGR system.