Study And Optimization Of Control Strategy For Electronically Controlled High Pressure Common Rail Diesel Engine

With the stricter emission legislations and the need of improving the engine performance, the electronically controlled fuel injection system has been universally applied for the advance diesel engine. High pressure common rail fuel injection technology, which is capable of achieving the goals of low emission, high performance, low fuel consumption and low noise level for the future engine, has been researched and developed by the overseas diesel engine manufactures. The GD-1 electronically controlled high pressure common rail system, as one domestic independently researched engine management system, had been launched since 2000.The research thesis of the paper is to study and optimize the control strategy for electronically controlled high pressure common rail diesel engine. The research comprises the general design of diesel engine governor, the design of torque controller, design and optimization of control scheduler, and design of injection pressure controller, and etc. The research is described as following:1. Based on investigation and research of the control strategy and operation principle of the foreign advance fuel injection systems, the control function, design target and technological measure of the GD-1 diesel management system had been decided.2. GD-1 diesel engine basic input controller and the engine operation state controller had been designed; as a result, the control accuracy and reliability of the engine governor for complex operating points had be improved. 3. For the application of the GD-1 diesel engine in the hybrid bus, a torque-based engine controller had been designed to replace the old fuel quantity based governor. Then the dynamics, economy, driveability and match flexibility had been improved.4. Based on the Matlab/Simulink tool, a simulation model had been designed to output the speed signal, design and validate the scheduler control strategy, which is used to detect the engine position quickly, precisely drive PCV valves and injector valves, and execute limp home function. So the operation reliability of GD-1 system had been improved.5. The injection pressure controller, comprises injection pressure control mode module and PCV driving mode module had been designed to improve the control flexibility and accuracy of the injection pressure for every diesel operating state.6. Based on the Matlab/Simulink tool, a simulation model had been built to analyze the common rail pressure build-up characteristics in the initial cranking process, in which the engine position had not acquired; then a novel frequently driving method had been designed to achieve targeted injection pressure as soon as possible, at last the optimized driving frequency of 30Hz had been obtained.7. In order to reduce the time for ascertaining the engine position when the only the crank wheel signal is useful in GD-1 engine cranking process, a novel strategy driving the PCV in long-duration pulse is designed. By use of the new strategy, the start performance in fault state had been optimized.8. During the development process of the GD-1 diesel engine, the method and measure to achieve the target of passing emission test had been researched, and the calibration process and method of the electronically controlled common rail diesel engine had been summarized.