Application Of PID Controller Performance Evaluation In The Idle Speed Control Of Engine

Control Performance Assessment (CPA), which attracts tremendous concern of the industrial and academic areas, has become a burgeoning field of investigation. Further studies of CPA are of great significance. Moreover, engine idle speed has a huge impact on the engine. Besides, the idle speed control, which aims at maintaining the engine expected speed at a stable level and fulfilling the needs for idle speed emission at the same time, is one of the basic problems of the auto control system. Hence, further researches on the idle speed control have a great significance to reduce emissions, improve the fuel economy of gasoline engine.This article is from the point of view of CPA with taking the control system of engine idle speed as the research object, to design a fuzzy self-tuning PID controller and PID controller by using the PID control circuit which is widely used in industry. With the help of Linear Quadratic Gaussian (LQG), this article will make a comment on the PID controller the idle system.Based on introducing the knowledge of thermodynamics and the average value modeling based on the theory, mathematical modeling of idle system of gasoline engine. To obtain the basic parameters and data engine from the enDYNA simulation software, the fitting model parameters. Through the establishment of Matlab/Simulink mean value model, to calibrate the model at the same input condition, the reliability and the precision of the model is verified.The model of discrete linear selected reference point average value of nonlinear engine, establish the state space equation:the throttle valve to control the input, load torque disturbance input, intake manifold pressure as the state variables of the system, the engine speed to control the output. From the load disturbance rejection based on angle and performance evaluation of LQG reference method for performance analysis of several groups of controller. Evaluation of idle PID control system in the load torque generating capacity of step disturbance from load disturbance rejection angle, while the performance evaluation based on LQG benchmark in the engine load torque disturbance and input and output noise, compared to evaluate the performance of control loop through the closed-loop system corresponding to the actual input and output variance the optimal index and LQG performance limit curve.Through the above evaluation methods, engineers can evaluate the control loop performance at the design stage, and make sure whether it is necessary to construct Fuzzy self-tuning link or other complex control links. Moreover, it can also help the driver to detect and repair control system failures before they actually occurs.