Based On The CAN Bus Fault Diagnosis System On Board For Vehicle

With the growth of the automobile industry and the introduction of electronic controltechnology, electronic degree of vehicle increases, power performance, control stability,safety and fuel economy of vehicle increase dramatically, relieves the environmental, energysaving and traffic safety problems globally. While introducing the electronic controltechnology, there are also other problems introduced, for example, thick wiring harnessmakes the limited space of vehicle more limited, operational reliability declines, probabilityof failure increases, difficulty of maintenance and repair also increases, data informationcontent needed to share rises. As a result, bussing technique and failure diagnosis technologyemerge as the times require, this makes the development of vehicle failure real-time diagnosissystem necessary.In this thesis, the bus with CAN bus network is research object, whose application layeris in accordance with SAE J1939protocol based on CAN bus protocol, through real-timeextraction and resolving the status and failure information from vehicle network, the real-timemonitoring of vehicle running status is performed. Applying data flow analysis method tocarry out online failure diagnosis, real-time warning and data storage, so that, the driver canbe well informed on vehicle status, the analysis can also help to provide the basis for vehiclemaintenance and repair effectively. This thesis mainly focuses on research and analysis ofCAN bus technology and SAE J1939protocol, analyzes the categories and characteristic ofvehicle failure, classification of failure diagnosis and diagnostic method of electronic controlsystem failure. According to the system requirement, data flow analysis method which issuitable to online failure diagnosis is employed, the suitable chip is selected to carry outhardware and software design. According to SAE J1939protocol, using CANoe software toperform hardware in the loop simulation and real vehicle test through extraction, resolvingvehicle information from CAN network and carrying out failure diagnosis. The result showsthat design of online failure diagnosis is reasonable and feasible.The failure diagnosis system proposed in this thesis has good suitability, its vehicle testhas been carried out on buses from KINGLONG, ANKAI and Foton. It can process correctfailure diagnosis and warning through real-time extraction of vehicle status and failureinformation, alarm the driver correctly.