부산대학교 도서관

In this paper, the transient conditions during fast startup are investigated to develop a fuel metering strategyunder HEV-like mode. The fuel mixture preparation and its effects on the combustion are analyzed in detail. Specifically, thecombustion in the first cycle is characterized under both conventional low-speed cranking startup and HEV-like fast startupmodes. The test results show that the enhancement of cranking speed has marginal effects on mixture preparation in the firstcycle. However, it prolongs the combustion duration and reduces HC emissions. The sensitivity of the fuel metering isevaluated for the initial cycles. The combustion in the 3rd ~ 5th cycles during startup is found to be fairly sensitive to the fuelmetering due to the effects of transient fuel film vaporization. The fuel metering in the first cycle has the most significant effecton the combustion and emissions during fast startup. Optimized fuel metering in the first cycle shows effective reduction ofHC emissions during fast startup process.