Development Of ECU Hardware System And Key Control Strategy For High Pressure Common Rail Injection System

Due to High Pressure Common Rail Fuel Injection System (CRS)'s functionality of controlling injection pressure, injection quantity, injection timing and injection rate independently and flexibly, it has become the best choice to meet the increasingly stringent emission regulations.Firstly, the development status and trends of CRS are introduced in the thesis, and then the mechanical assembly and its working principle are elaborated based on the Bosch's third generation common rail injection system. Design of ECU hardware systems based on circuit simulation software has being the mainstream design method, therefore the drive circuits and diagnosis modules for injector and pump solenoid valves are designed in the PSPice platform. The V type development flowchart of ECU control software and software architecture are deeply studied, the Matlab/Simulink and RTW Embedded Coder tool sets are used to implement the control strategy modeling and automatic code generation, thus enhances the control software's portability. As the functionality and complexity of electronic control unit increases, the real-time scheduling solution is designed to complete the reasonable control software scheduling.The maturity of the control strategy is the prerequisite to achieve the precise control of multiple injections of CRS. The pressure wave characteristics in injector nozzle and pipe bore, caused by multiple injections, are deeply studied in pump test bench. Then, the control strategies for pressure control and multiple injections are completed. Finally, the calibration of target diesel engine is implemented to prove the hardware reliability and effectiveness of control strategies.