A transient fuel film identification model for gasoline engines was built based on wavelet networks. The ant colony optimization (ACO) was used to initialize wavelet networks parameters as the initial values for the model so as to improve its convergence and precision. Transient air-fuel ratio was tested with this model, simulated with experimental data and compared with the actual air-fuel ratio. Results show that the model initialized with the ACO can effectively and precisely identify the transient fuel film with faster convergence and bette...