Study On Electronic Control System For Gasoline Engine Based On Real Time Operating System (RTOS)

Under the stress of strict emission laws, more and more advanced technology has been applied on engines. Almost all of the technology is implemented via electronic control system, thus leading the complexity of engine control system. With the development of MCU and electronic technology, the embedded operating system has been utilized widely in recent years .Therefore, the development of engine control system based on embedded operating system has been the focus and trend in the field of automotive electronics. The industry standard OSEK/VDX for vehicle embedded operating system was published in 1993 in Europe, providing the base for application of real time operating system.After reviewing a quantity of technical issue and literatures, the project of developing engine control system based on embedded operating system has been carried out. First, the OSEK/VDX standard and working principle of embedded operating system are analyzed. Furthermore, several popular embedded operating systems have been investigated, and open source real time operating systemμC/OS-Ⅱis chosen considering the condition of research lab . Secondly, the kernel configuration ofμC/OS-Ⅱand porting rules are familiarized by author and the system is ported to INTEL80C196KC MCU. For the characteristic of 80C196KC, the porting program is designed and tested, and the testing results indicate the success of porting. Then according to the function requirement of control system, the schematic and PCB design of ECU arefinished, including: MCU system hardware design, sensors input channel and actuator output channel designs, also the RS232 communication circuit design between MCU and PC computer. The bad condition of high temperature,vibration and strong electromagnetic radiation under which the engine control system works being taken into consideration, many anti-interference methods are employed during the PCB designing process.After the design of hardware for control system,the software based on embedded operating system is developed. Based on control system function and software demanding analysis, the general design project for control system software is carried out.In the porting system the application program for electronic control system is developed for the requirement of engine operation. For the reason that the embedded operating systems are working based on tasks, the tasks are classified and the priority of the task is determined by author initially. For theμC/OS-Ⅱis a preemptive kernel for priority instead of quantum, the task must be given a unique determined priority. From the viewpoint of engine control strategy and development cost, the Semaphore is chosen for communication between tasks. Because theμC/OS-Ⅱis only a real time kernel,the drive programs need to be designed so as to connect the software and hardware.For the reason above ,two drive programs ,that is,A/D conversion and SCI communication are designed by author repectively.After the development of control system, it needs to be verified. The DA468 engine produced by Dongan Engine, Ltd is chosen as research object. The testing bench is setup and testing devices are commissioned, then the research is carried through in this bench. The injector is the most important actuator, so the flow characteristic must be calibrated firstly. The ECT sensor plays a role as correction for injection and ignition, therefore the output characteristic should also be calibrated exactly. The fuel injection quantity is decided by fuel injection pulse width if the flow characteristic of injector is determined.For the fuel injection pulse width map is determined via look-up tables in engine control system, it ought to be made initially. The ordinary engineoperation conditions being considered, the engine speed and MAP are classified to cover the high-frequency domain of engine operation conditions. The ignition advance angle map is made after the fuel injection pulse width map. For the ECT (engine coolant temperature) effect injection and ignition significantly, the correction map base on ECT is a plus for system. The engine characteristic test is implemented afterwards, and the engine performance curves indicate that: the electronic control system based on embedded operating systems can make the engine output target power and torque, which means the success of control system.