| The development of automotive industry, carries convenience to people, but inthe other hand, has much negative influence as well. More accurate and reasonablemonitor and diagnostic technology will improve the vehicle performance. Besides,there are more and more electronic components in the automotive, and field buswill take the place of the traditional harnessto transmit the information. Based onCAN bus mechanism, the task build up new message transmitting methods,differential service mode inside nodes, and more perfect diagnostic system.As thestartup of bus communication and diagnostic technology is later in china than thatin abroad, there are no similar technology with self-owned intellectual propertyrights in china, and from1stJuly2009, every automotive must be installed with OBD(on board diagnostic) system, so the diagnostic technology with self-ownedintellectual property rights must be developed as soon, and it is the emphases ofthis paper.The progeny of this paper:(1) Analyzing the development trend of global automotive industry in detail, tofinally decidethe theme of the paper;(2) Based on the international organization for standardization, analyzing theprinciple of CAN bus communication and principle specification, and compilingthe configuration of network principle; rising up a new message transmittingmode of based-social routing, and network encode communication mechanism;(3) Analyzing the diagnostic strategy and theory on vehicle emission diagnosticsystem, redefine differential service mode of message in node;(4) Analyzing the fault types, debugging the developed system, and realizing theinteraction between operator and diagnostic system componsed by ECU and PC,based on the actual program, adjust the OBD system successfully.The communication mechanism of CAN bus, the service flow of OBD and thestructure of require and response frame of DTC are analyzed in this paper, message transmission based on social network encode communicationmechanism, and differential service mode in node are introduced in the task,and be realized by principle configuration. The OBD system in paper has beenrealized, and it is important for the development of diagnostic and bus in china. |
