Carborne Information System Based On USB

Carborne information system is the integration of all the electronic equipments of the car, it mainly consists of carborne information display system and malfunction diagnosis system. The carborne information display system can display the electronical map and the position of the car etc, on the LCD when the car is running. The malfunction diagnosis system can display the real-time status of all the key parts on LCD, such as the pressure of the tires, whether the engine is ok, whether the temperature is ok etc. At the same time, it can also transmit the data through the carborne network, using the special diagnose devices examine the car through the interface of the car.The base of the malfunction diagnosis system is carborne network in the car. Now, in the existing cars that have the malfunction diagnosis function, the familiar networks are car body network CAN (Controller Area Network) and malfunction diagnosis network K line and L line. CAN network and K and L line network are two absolute network. The CAN network can transmit at a speed of 256Kbps, it belongs to the high-speed network and is special for connecting the high-speed equipments such as engine, draw controller etc. It can ensure the real-time feature of the data gathering. K line and L line are the physics layer of the KWP2000 malfunction diagnose special communication protocol, it is used specially to gather the malfunction information of all parts, then sends these information to the application layer of KWP2000.The malfunction diagnosis system that discussed in the paper uses car body network instead of the K and L line network, it unites the two abstract network to one, predigests the inner network more. It uses car body network transmit the real-time data of all parts, uses the CAN/USB gateway realize the conversion between CAN data frames and USB data frames, then transmit the CAN data to malfunction-diagnosis program that in the portable computer through USB. The program uses the universal malfunction diagnosis codes in the world, it can ensure the currency of the system.The malfunction-diagnosis program in the portable computer is used toanalyze the standard malfunction codes to ensure the reason and location of the malfunction. It can make the maintenance workers maintain the cars quickly and conveniently. Using this technology in the malfunction diagnose of the cars can reduce the difficulty and expense of automobile reparation greatly.