Development of control strategy for SI engine cold start

Engine cold start is an important issue in the automobile development. The traditional control strategy of cold start is an open-loop control that results in a high HC emission. In the paper, the improved control strategy for SI engine cold start is discussed. And it indicates that the A/F ratio, ignition time and the desired idle speed are the 3 important parameters for the cold start. In order to control A/F ratio accurately, the study builds an exact fuel injection model of cold start, and uses a closed-loop control strategy thorough measuring cylinder pressure. In the end, one experiment is made on a type of automotive to validate the accuracy of control strategy. The result shows that the time of cold start, about 0.616s, is shorten, the maximum speed is lower from 2000rpm to 1500rpm, and the HC emission can be reduced about 16%.