Simulation And Experimental Study On Air Fuel Ratio Control For The PFI Gasoline Engine

Air-fuel ratio control technology is the key to solve the problem of vehicle emissions,but also an important way to improve the engine power and fuel economy.Therefore,this paper takes ZS157FMI-3 type PFI gasoline engine and BYQ125(J) type motorcycle as the object,from the steady-state conditions to broaden transition condition,from a single cylinder engine to extend the vehicle,through simulation and experiment carried out systematically, explores the new methods of the PFI gasoline engine and vehicle air fuel ratio control.Firstly, the PFI gasoline engine air-fuel ratio control simulation under the steady-state conditions.Based on GT-Power simulation platform, access to the engine structure and performance parameters, establish a one-dimensional simulation model of the engine and test calibration.Using the method of exhaust components concentration measurement to build the model of oxygen sensor.Through the design of PID controller and the parameters setting,to achieve the air-fuel ratio closed-loop feedback control under the steady-state conditions.Secondly, the PFI gasoline engine air-fuel ratio control simulation under transient condition.Taking into account the intake port oil film dynamic transmission mechanism and fuel compensation strategy,based on the X ?? oil film model,deduce the x-y discretization of mathematical iterative equation for oil film model.The oil film parameters are identified by test, establishes intake port fuel compensator and verification,to achieve the air-fuel ratio open-loop feedforward control under transient condition.Finally, the vehicle operating conditions air-fuel ratio control simulation and experiment.Based on neural network control to build the engine mean vaule model,using detailed engine model to generate the DOE sample data and train the neural network to achieve the predictive function. Taking BYQ125(J) type motorcycle as the object,build one-dimensional simulation model and carry out calibration. Based on the modification of electric motorcycle,design experimental and simulation conditions, by comparing the experimental values and simulation values,verify the accuracy of the vehicle air-fuel ratio control simulation model.