Study Of Control Software Of High Pressure Common Rail System On Embeded System

High pressure common rail fuel system is a high flexible fuel system, delegates the developing tendency of diesel engine fuel injection technology and has been the researching hotspot for famous diesel producers all over the world. Its excellent performance provides enormous possibility to optimize diesel engine performance. GD-1 (the first generation green diesel)is one of the high pressure common rail systems, which are developed independently in China. Embedded real-time operating system (RTOS) was introduced in the control software of GD-1 high pressure common rail system, this paper describes the researching work on control software overall design, multitask design, control program realization, code generator, calibration and monitoring system design, hardware-in-loop simulation system design.1. Based on RTOS, the control software of high pressure common rail system was studied, the control strategy was designed in hierarchy structural programming mode and corresponding control algorithm was studied. Embedded RTOS was introduced to study control software of GD-1 high pressure common rail system, based on this RTOS, the control software was designed as a whole and divided into many modules. All modules of control strategy were compartmentalized into 12 tasks; every task was detailedly designed and assigned specific priority. Tasks were managed and scheduled, the priority-based scheduler made better use of software/hardware resources of ECU, and allowed all events to be handled as quickly and as efficiently as possible.2. The control algorithms and functions were graphically designed and written in Matlab/Simulink, and transformed into ANSI C codes by a automatic code generation software Targetlink, which shorten the debugging peirod and even ease of development process. They also provide with powerful simulation and analysis functions, help to find, analyze and settle those problems on control model during the developing process. The"makefile"file was hand written to ease the compiling process and to shorten the compiling time by"make"instruction. Consequently the control software was completed based on embedded RTOS.3. A calibration and monitoring system was designed and developed firstly in china based on embedded RTOS. CAN communication hardware is realized, and corresponding programs were designed: controller area network (CAN) driver, CAN calibration protocol (CCP) driver, monitoring task and calibration task were designed: The cyclic mode was used in monitoring task and the interrupt mode was used in calibration task, and their task priorities were assigned lowest, which ensured the real-time communication and interruption for main control program simultaneously. The online calibration memory was designed and online calibration was carried out to those data in calibration RAM. Mirror memory and calibration RAM optimized write and read accesses to the controller.4. A hardware-in-loop (HIL) simulation system for high pressure common rail diesel engine was designed based on CAN communication and multithread technology. The simulation ECU was developed to convert and send all necessary parameters for object ECU and PC. An accurate measurement was achieved to actuator signals with no-contact current sensors. Multithread technology was used: Labview was used to develop the monitor-control interface as main thread; diesel model and communication threads were programmed by Visual C++ and ran in the background as sub threads. CAN communication protocol was adopted and communication programs were developed separately for simulation ECU and PC, communication data were converted with an USBCAN card and an accurate, reliable and quick communication was achieved between simulation ECU and PC, with baud rate up to 500k bit/s.5. Finally V-type development platform based RTOS was achieved independently. Function modules were implemented by Matlab/Simulink, and program code were generated by Targetlink, cut down debug phase and development period. HIL simulation system was used to test ECU, reduced the development period and costs. Highly efficient calibration and monitoring system reduced the developing period of engine and improved efficiency of the ECU. Based on embedded RTOS, compartmentalizing the control software into separate tasks simplified design process; Function modules were managed and scheduled by RTOS, made the control system be easily designed and expanded during developing process of control software.6. This platform has been successfully used in studying the control software of GD-1 high pressure common rail system. After the following test and debugging, HIL simulation, fuel pump test bench and diesel test bench, GD-1 high pressure common rail diesel engine has achieved quick start, steady idle control and good transient performance. The results showed that the control software and scheduling strategy were rational, and accomplished good control function. The control software of GD-1 high pressure common rail system was feasible.