A Model-based Air-fuel Ratio Control Scheme for Gasoline Engines under Fuel Injection Path Changing

This paper presents a model-based design approach to feedback air-fuel ratio control for SI engines during fuel injection path changing. For the SI engines, emission performance during transient mode is remarkably influenced by air-fuel control, and to improve the efficiency of combustion engines, the fuel injection path is frequently changed from port-injection to direct injection or reverse. Therefore, how to describe the dynamics during the fuel path changes and to compensate the fuel injection are important issues to achieve good transient performance of air-fuel ratio. In this paper, a feedback control scheme with a mode changing command triggered feedforward compensation is proposed, and experimental validation on a six cylinders engine will be demonstrated.