Study On Electronic Control And Optimizing Techniques Of Fuel Injection System In Small Gasoline Engines

Engine electronic control technology is regarded as an important method to improve both power and economy performance and reduce the exhaust emissions. It is widely used in automobile industry, which becomes a main technology on saving energy and reducing the exhaust emissions. Study of optimization on electronic control system for motorcycle engine K162FM is carried out in this project.Performance testing bench is set up based on the characteristic of small Capacity engine and research requirement. The fuel supply system and the intake system are redesigned. The design principle of software and hardware is proposed. The hardware system of electronic control unit (ECU) is developed using the mix signal system chip of Cygnal Co.. Then the signal modulation circuit and the drive circuit are designed. The software system of ECU is designed according to interrupt plus main control program. Optimization estimate method for electronic control gasoline engine intake flowrate based on extended kalman filter (EKF) is investigated. The intake quantity closer really value is obtained, and the control precision is improved for air-fuel rate of engine. The different control strategies are set up according to various engine performance conditions.The small capacity gasoline engine calibration system is developed for control parameters to fit experiments on electronic control injection sysytem. Real-time communications can be realized with ECU via RS-232C serial port. Analyzing data and calculating, obtaining the best work condition and drawing maps can also be realized by the system. The accurate control parameters are obtained.In this paper, examination experiment of idle condition is designed according to principle of system identification. By off-line parameters identification, dynamic model is built, whose input variable is injection width and output variable is idle speed. The idle model is simplified and corrected. Based on the model, a predictive-PID Controller is built, and it is used to replace optimize control problem of predictive control. Result of simulation indicates that predictive-PID controller has good effective control. It can realize the constant speed control of idle condition. Optimization of control variables is an important part of electronic control gasoline engine research. Multi-object optimizing theory is adopted when control parameters is optimized. The optimization control parameters are gotten according to the data tradeoff. The contrast test is carded out on fuel economy, emission quality and power performance of the electronic controlled engine with the original one. The result indicates that the fuel consumption rate and the exhaust emission decrease in large scale. T power performance is improved. Study shows that the ECU system designed is successful, and the control strategies and optimization method are right. It will have a good prospect application.