Study On Diagnosis Expert System Of Electric Controlled Engine

The wide use of electronic technology in automobile totally changes the automotive structure and performance, new structure theory and devices are springing up and putting forward of higher demands to the maintainers. Now compared to the foreign countries, there were a wide gap of domestic fault diagnosis technology, the study of diagnosis expert system of electronic controlled engine has significance to improved and enhance domestic fault diagnosis technology.This paper elaborates the utilization conditions of electronic technology in engine and sums up the fault feature of electronic controlled engine, deeply analyze the theory and technology of fault diagnosis, theory and limitation of traditional expert system, theory and advantage of the expert system based on neural network. Integrated expert system base on fault diagnosis combined by base on symbol processing and expert system based on neural network is further put forward.The core of this paper is to establish knowledge representation of deterministic fault appearance and reasoning strategy, module design of fault code diagnosis and data flow analyze, software design of fault shape diagnosis based on neural network. According to the knowledge of the structure, principle of the engine and the experiences from experts, the fault trees are established. Extracting the training samples from fault trees is given to neural network for study and for the formation of part acknowledge database of weight value and threshold value after study. In this paper there was a detail account of BP network and its algorithm steps stimulated by "sigmoid" function.The software is designed by VB6.0 and Access, its operation system is windows2000. This system has collected fault code, data flow analysis, inspection method of ignition system and so on, the user can add, delete, alter and inquire conveniently.The main direction of studying to diagnosis expert system is how to better realize inspection and diagnosis on line, establish a sort of diagnosis system that is simple intelligent, adapted to the conditions of our country and can be popularized in practice. So, the studying to fault diagnosis expert system has important economic value and wild utilization prospects.