Common Rail Diesel Engine Fault Diagnosis System (dsm)

The fault diagnosis system of high-pressure common rail diesel engine can acquire kinds of diesel engine's state parameters in real time when vehicles are driving normally, in order to monitor the work status of all component parts of electrical control system continuously. Once there are some abnormal situations resulting in increased emissions, the fault information will be sotred and the corresponding fault emergency module will be started to implement fault-tolerant function which ensures the diesel engine has certain capacity of working under some failures. The fault diagnosis system has made the power and safety of modern diesel engine have been greatly improved, and meet increasingly stringent vehicle emission standards at the same time. While, so far, fault diagnosis systems used in domestic diesel engines are basically mature products from abroad, which requires the self-developed fault diagnosis system urgently.Based on the above condition, this paper has summarized the current status of fault diagnosis system at home and abroad, analyzed its future development direction, and then researched the working principle and related knowledge of fault diagnosis system in detail. Integrated with the theoretical knowledge, international standards of on board diagnosis system and the overall design patterns of high-pressure common-rail ECU in our laboratory, the control strategy of fault diagnosis system on high-pressure common-rail diesel was proposed at full and systematically based on the ASCET software platform. Predebouncing, fault path handling mode and fault state control were applied when designing the fault diagnosis system for solving the difficulties how to distinguish the true or fake failures, how to differentiate various fault type and fault severity and how to determine the time lighting the malfunction indicator lamp and storing the fault information in the error memory.After that, the software of high-pressure common rail diesel fault diagnosis system was designed base on the control strategy. According to the modular design concept, the fault diagnosis system model was established using ASCET software and the main control module was explained detailed. Finally, the main application parameters were calibrated and the each module of fault diagnosis system was simulated respectively. The simulation results verified the correctness of control strategy and the feasibility of the module functions, which indicated that the diagnosis function of fault diagnosis system could be carried out effectively.