Research On Transient Air-fuel Ratio Control Of Motorcycle Gasoline Engine To Deal With China ? Emission Standard

Environmental pollution,energy scarcity are becoming increasingly serious,emission regulations are becoming more and more stringent.In order to solve the increasingly serious problem of emissions,motorcycle engine has gone toward the direction of EFI gradually and reduced the use of traditional carburetor.For this stage the China III emission standards is in the implementation and the China IV regulations will be implemented,the solution is still in the three way catalytic converter.And the use of three element catalytic converter need air-fuel ratio controlled near theoretical air-fuel ratio.In the actual use of motorcycle engine,in most cases are under the transient conditions of throttle opening and speed changing,increase the difficulty of air fuel ratio control.The air-fuel ratio deviated from the theoretical air-fuel ratio,not only make the engine performance decline,will also affect the efficiency of three element catalytic converter,the emission of engine would rise.Therefore,the research of the transient air fuel ratio control has important practical significance to reduce the emission of the engine.This paper used the engine mean value model modeling method to build the engine model,including the intake model and fuel dynamic model.In addition,considering the air-fuel ratio signal delay,a delay model was built,making the model more accurate.Genetic algorithms was used to identify parameter,and the model was proved by bench test data,verifid the validity and accuracy of the engine model.The results show that the ratio overshoot is less than 10% of the air-fuel ratio control using transient air flow prediction model based on BP neural network,can quickly make the mixed gas recovery to stoichiometric mixture within 2S,and also avoiding the swing of traditional PID control.Using the transient air flow prediction model based on BP neural network with oil film compensation,its overshoot is reduced by about.It is proved that the algorithm can effectively reduce the influence of the dynamic characteristics of the fuel transport,and can improve the control precision of the air fuel ratio...