Software Design And Implementation Of Automobile Engine Fault Diagnosis System

The engine fault diagnosis system is a subsystem of the engine electronic control system. The fault diagnosis subsystem is necessary to ensure the safe and reliable operation of the engine. As the representative by the United States, since the 90’s, to control the exhaust gas emissions, supplemented by strict legal text, OBD (Diagnostic On-Board) standards as a starting point, each car manufacturer instead of implementation of its own engine fault diagnosis system, developed into a must be in the form of a unified fault code output, and thus provide standardized engine fault diagnosis service.In this thesis, by analyzing the OBDII standard, and the requirement of engine fault diagnosis software system, the software architecture of fault diagnosis is presented. The design of the key parts is presented, and the validity of the software architecture is verified.The main work done by the author is as follows:(1) The engine fault diagnosis software is a subsystem of the engine control system, the operation will inevitably conflict with the existing control system in resource scheduling. In this research, the solution to the resource conflict is studied, and the method of setting up the backup resource is put forward, which is developed base on the idea of the OSEK-OS (Open Systems and the Corresponding Interfaces for Automotive Electronics-Operating System).(2) The data structure of the software is put forward to realize the OBDII (Diagnostic II OBDII) system’s standard engine fault diagnosis process.The software architecture of the engine fault diagnosis has been applied to a certain car brand, and showing the good scalability and reliability.