Simulation And Drive Circuit Research Of Solenoid Valve In Common Rail Injection System

With the future more strict emission legislation and development of electronic control fuel injection systems on diesel engine, common rail injection system, for its advantage, is becoming the evolution trend of diesel engine using in car. Common rail injection system can meet the complex need of jet. Thereby, it is necessary to research on the drive circuit of solenoid valve to improve the response of injector.This thesis presents the research results achieved by the author on the area in drive circuit for electronic controlled injection system of CR diesel engine. Taken CR system of Bosh for example, this thesis has accomplished hardware and software design on injection control and elementary experiment.A simulation model of high speed solenoid valve was developed in this thesis. With the model, the influences of both fabric and control parameters on the characteristic of solenoid was analyzed.Hardware was designed according to character of the control object. The drive circuit adopted two voltage source with high voltage and low voltage, and the solenoid current was controlled by the PWM signal. By simulation and calculation, circuit parameters was ascertained. Finally, the whole system hardware has been designed, including singlechip unit, processing circuit of digital and analog signal from sensor, drive circuit and electrical source circuit , which contained two different methods, boost converter and full-bridge converter.The control strategy of injection quantity and injection timing was also analysed. With MC9S12DP512, the software of signal processing was carried out, as well as the software of injection control, that realized the precise control signal for the drive circuit.Finally, elementary experiment was done. The test result verifies the anticipated control effect of the drive circuit was achieved, which is effective to improve the response of solenoid.