Numerical Simulation And Idling Control Of A Gasoline Engine

With the promulgation of new automobile emission regulations,higher requirements have been placed on engine performance.To improve engine performance,control strategies and control algorithms are needed to be promoted.For this reason,it is necessary to study engine performance characteristics to provide a basis for formulating control strategies.The engine idling condition is one of the important driving conditions of the engine,and its control performance directly affects the engine’s emissions and energy consumption levels.This paper focuses on the numerical simulation of engine performance and idle speed control.the main works of this paper are the following aspects:(1)The engine bench test was completed,the 475 engine numerical simulation model was built,and the bench test data was used for calibration to ensure that the model was in line with the actual situation.Based on the established GT-POWER model,the effects of the change of air fuel ratio and ignition advance Angle on engine performance were analyzed.The results show that with the increase of air fuel ratio,the engine torque increases first and then decreases,and the effective fuel consumption rate increases gradually.With the increase of ignition Angle,the engine torque and effective fuel consumption firstly increase and then decrease,and the effect of the change of ignition Angle on the effective fuel consumption rate is lower than that of the air-fuel ratio.(2)Build the engine mean value model,and use the bench test and numerical simulation model data to build and calibrate the mean value model.In this paper,the oil film evaporation model and the inlet pressure observation model of the intake pipe are added to make the model can be simulated in steady state and transient state.The power output module is constructed by parameter fitting,which simplifies the model and does not affect the accuracy.The establishment of the mean value model provides a reliable controlled object for the verification of subsequent control algorithms and control strategies.(3)the establishment of an engine speed PID,FUZZY PID and FUZZY neural network PID control algorithm,the engine the engine speed control effect on the average model of model simulation,the simulation results show that the FUZZY neural network PID control algorithm under the regulation of the engine speed has a faster speed,shorter regulating time and smaller overshoot.(4)Based on the influence of the change of engine ignition Angle parameters on the engine torque output characteristics,the engine torque is reserved by reducing the ignition advance Angle.According to the idea of torque reserve,the idle torque compensation model is established.When the engine encounters unexpected load disturbance,the ignition Angle is adjusted to obtain partial torque supplement to maintain the engine idle speed stability.