To achieve effective control of transient air-fuel ratio for gasoline engines

a composite control method is proposed

which consists of inverse model feedforward based on least squares support vector machine(LS-SVM)and feedback control with model-free adaptive control(MFAC).The inverse model of transient air-fuel ratio system was set up with LS-SVM

which is able to dynamic compensate intake flow with feedforward control. And a MFAC feedback controller was used to as a compensation both internal and external disturbance in real time. Then the inverse model and the composite control method are used to simulate transient operating conditions which are compared with the actual acquisition of the air-fuel ratio. The results show that the inverse model based on LS-SVM can accurately approximate the air fuel ratio transient process

and this method has stronger robustness and anti interference combine the MFAC feedback control. Therefore

the composite control strategy has good control performances and can improve the control precision of air-fuel ratio in transient conditions.