Study On Fuel Injection Control And Fault Monitor Of High Pressure Common Rail Diesel Engine For Car

As a type of engine for car, electronic control high pressure common-rail diesel engine is one of the best choices in saving energy and protecting environments. These research of fuel injection control and fault monitor to the high pressure common-rail diesel engine is very important to improve the fuel injection precision, to save energy and decrease emission, to strengthen system operating stability and reliability and to optimize the engine performance. In this dissertation, fuel injection control and fault monitor had been systematically studied by reading abundance correlative literatures and referring oversea correlation products, and supported by "Development on New Generation Energy-saving and Environment-protecting Efficient Internal Combustion Engine for Car" (It's the National High Technology Research and Development Program of China,"863"Program) and "Development and Application on Key Technologies for Clean and Energy-saving Diesel Power System Used in Passenger Car"(It's National Key Technology R&D Program).The main research contents include following respects:(1) Analyzing the sensors and actuators characteristic, the hardware of electronic control unit was designed with core of MPC5634 microcontroller which is a new PowerPC 5600 32-bit processor and is fabricated in 90 nm process. The software architecture on base of component layer model was established. Every layer function and layers'interrelation were discussed. The hardware and software foundation was set up to validate control strategies.(2) A new camshaft with four long teeth and four short teeth was adopted; the segment pattern matching was used to quick position synchronization. The test injections and the pattern recognition were activated when the camshaft or crankshaft sensor signal were missing during limp home. A dynamic plausibility check of camshaft and crankshaft sensor signal was done with predicted windows. The strategy on computation of engine speed was discussed. The bench test results showed that the position synchronization could take place in 180℃A.(3) A new control strategy for the common rail pressure was brought forward based on genetic algorithm and non-linear PID controller. The technologies of integrator separateness and pre-control for pressure governing were introduced. The optimal rail pressure control under different conditions was realized by online adjustment of PID control parameters. The control fluctuation of rail pressure was limited in 1.5%.(4) A new fuel quantity calculation method was put forward on basis of engine torque. The six multiple-injection coordinate control model was upbuilt. The fuel injection energizing time and the start of energizing were calibrated in different conditions and corrected dynamically with environment factors. Some key map date was calibrated with universal calibration software which was developed by us.(5) A new layer model to engine default monitor was built. The functions of every layer and the monitor strategies with some representative default of every layer were discussed. A perfect engine default monitor system was established.(6) All error handling functions were summarized under diagnostic management system. The concepts of default debounced and default healed were introduced, simultaneity their strategy based on time and event was explained. The concept of function identifier was imported, inhibit handler, exclusion list and dynamic priority list were adopted to realize limp home. The detailed fault information was stored to exchange data with diagnosis scanner according with OBD emission legislation.The research work developed by author has been successfully used on DK4A diesel engine in AVL bench. The test results showed that the emission of engine which was controlled by injection control strategy accorded basically with EURO-Ⅲ, the power curve was similar with the level of former electronic control unit; strategies of fault monitor to engine could strengthen markedly system operating stability and reliability. It can be said that the research work offers a new way to upgrade the electronic control unit of high pressure common rail diesel engine, that the research have higher theory and utility value.