Research And Application Of Driving Module And The Fault Diagosis For High Pressure Common Rail System

High Pressure Common Rail System (CRS) is widely used on the diesel to meet the increasingly stringent emission regulations. CRS has the functionality of controlling injection pressure, injection quantity, injection timing and injection rate independently and flexibly. It is necessary to improve our country’s self-research on the CRS. Based on it, the thesis has finished the design of driving module and the fault diagnosis for the CRS and the development of rail pressure control.Firstly, the development status and trends of CRS were introduced in the thesis. Then the mechanical assembly and its working principle were elaborated based on the Bosch’s common rail injection system. Referring to the characteristic of solenoid valve’s driving, the design of driving circuit was finished to meet the requirement of CRS’s driving module. And the respective driving current was derived. Due to lots of high speed solenoid valve used on the CRS, the design of the universal method for fault diagnosis of solenoid valve was completed. The circuit was finished according to the driving character of solenoid valve. And software of fault diagnosis by the way of Fuzzy AHP was completed after analyzing the condition of fault diagnosis. Based on the research of driving circuit’s characteristic of pump and injector’s solenoid valve, corresponding circuit for fault detecting and diagnosing was proposed. And its veracity was proved through simulating circuit by software on the PC. The integrated fault diagnosis module was completed after the diagnosis algorithm was proposed.Based on the design of CRS’s driving circuit, the way of closed-loop control strategy of rail pressure and respective algorithm was put forward after deeply research the principle of rail pressure control. And the calibration was finished on pump test bench. Then the experiment of rail pressure control was finished on diesel test bench when the diesel was on the state of start-up and speed-up. So the security of driving module and validity of rail pressure control strategy was validated.