Research On Air-Fuel Ratio Control Strategy Of The Engine Burning Ethanol-Gasoline

With the rapid development of economy and the increase of automobile amount, the environmental pollution and energy shortage problem is becoming increasingly serious. In the case of without adjusting the structure parameters of the engine, ethanol-gasoline (E10) as an alternative fuel is widely used. Because the electric control system without making any change, the engine is still in accordance with the gasoline combustion control, which have a certain effect on the engine performance. Air-fuel ratio is an important factor influencing the gasoline engine power performance, fuel consumption and emission of pollutants. So the paper is studying the air-fuel ratio control strategy mainly on the engine burning ethanol-gasoline (E10) with steady-state and transient condition.Firstly, The engine air-fuel ratio control strategy is simple introduced, which is mainly including the classic control strategy and the intelligent control strategy of air-fuel ratio. The ethanol-gasoline (E10) for the physical and chemical and the characteristic of ethanol as fuel are analyzed; The test comparison of engine burning gasoline and ethanol-gasoline (E10), through the test, we can draw power performance, fuel consumption and the concentration of pollutant emissions are contrasted. The research of air-fuel ratio is studied for burning ethanol-gasoline(E10) and gasoline, reaching a conclusion that when the engine fueled with gasoline and ethanol-gasoline (E10), Air fuel ratio is an important factor for the difference performance of gasoline engine.Secondly, This paper presents a mean value engine model(MVEM), which mainly consists of three subsystems--the air-flow dynamics, the fuel-flow dynamics and the crankshaft dynamics. The air-flow dynamics model is mainly consists of three subsystems--throttle body sub-model, intake valve body sub-model and Intake manifold sub-model. Dynamic effects of oil film was analyzed to establish the fuel supply model with compensator. The establishment of a simulation model of engine based on mean value model in Matlab/simulink environment. And mean value engine model burning gasoline carried out simulation of the air-fuel ratio.Finally, In steady-state conditions, the engine is burning ethanol-gasoline(E10) fuel injection pulse width which is corrected and the use of conventional PID controller, The establishment of steady state conditions of air-fuel ratio control model in Matlab/Simulink environment, comparative analysis of simulation results with the engine fueled with gasoline. In transient conditions, Combines classical PID control theory and fuzzy control theory and design of the fuzzy self-tuning PID controller, And the establishment of the transient air fuel ratio control model in Matlab/Simulink environment, and comparative analysis of simulation results with PID controller.