Transient Fuel-Film Compensation Strategy of PFI Gasoline Engine Based on Combined Film Model

Abstract

Abstract. For port-injected gasoline engines, an innovative strategy of transient fuel-film compensation is proposed to eliminate the impact of fuel-film dynamic effects and improve the transient air fuel ratio control accuracy. A combined fuel-film model composes of a long-term fuel-film and a short-term fuel-film was established. A transient fuel-film compensator model was analyzed in detail. The respective term of the fuel-film model is calculated by a share factor. The decay coefficients control the fuel compensation quantity and the active time. The validity of above models were verified though engine bench tests. The results show that this new strategy can effectively suppress the λ offset during engine transient condition, the transient lambda deviation is less than 5% and stabilized within 1 second.