Research Of Air-Fuel Ratio Control Strategies For Motorcycle Engine And Emission Control Technology

With quantity increasing rapidly,motorcycles bring not only so much convenience for mankind but also serious problems of pollution emissions. National stage III emission standards engender serious challenge for motorcycle manufacturers. EFI(electronic fuel injection) system and Three-way catalylitic converters are the most effctive means to resolve National stage III emission standards. Precise air-fuel ratio can not only reduce the generation of pollutants effectively but is the necessary condition to ensure the transformation efficiency of three-way catalytic convertres.In this paper, important motorcycle emissions regulations in the world,EFI system and Three way catalylitic converters are introduced. Several methods applied to the air-fuel ratio control are presented respectively,such as the common control strategy based on the look-uping tables,other control strategies based on classical theory, intelligent control theory and modern control technology.And control strategy based on fuzzy-PID are designed for motorcycle engines.Air-fuel ratio control model including the air-flow dynamics submodel and the fuel-flow dynamics submodel are established in this paper,and the air-fuel ratio control simulation model is built up under the Matlab/Simulink environment.Compared with PID controllers based on classical control theory, fuzzy-PID controller designed in this paper has higher precision. The results of simulated experiment show that the control method can achieve precise control of air-fuel ratio and the air-fuel ratio can be controlled near the theory air-fuel ratio.According to K157FMI engine's original emission characteristics, the catalyst composition and amount, volume of carrier, expansion tube angle of three-way catalytic converters are designed and calculated.