Research On Remote Communication System Of Fault Information For SI Engine

With the improvement of people's safety consciousness,OBD(on-board diagnosis)system has received more and more attention because of the safty,reliability and stability of engine,The latest emission regulation “China VI” also propose more stringent requirements.In addition,the application of information technology in the engine field in recent years has become a research hotspot for some companies and universities.Besides the OBD standard is gradually transitioning from the current OBD-II to the future OBD-?,in which the fault information telecommunication can not only be the basis for providing information exchange with remote platforms,but also can greatly improve the real-time performance and reliability of OBD systems.In this paper,the fault information remote communication system of vehicle engine is designed.This system is mainly used to diagnose the engine and upload the diagnostic results to the remote end for processing.The system contains three parts.The first part is the design of few added systematic diagnostic modules for the emission regulations “China VI”.The second part is the realization of CAN to WiFi remote communication.And the third part is the development of remote end software and establish of fault code database.Compared with the emission regulations “China V”,the emission regulation“China VI” has added four new diagnostic projects.The diagnosis of the fuel evaporation system(EVAP)and the crankcase ventilation system(PCV)are selected in this paper to respectively analysis their failure hazards,failure causes and diagnosis methods.Based on this,the corresponding logic is formulated through MATLAB/Simulink and the diagnostic condition is designed to start the diagnosis module.The selected CAN to WiFi communication hardware is from the CAN to WiFi module designed by the Beijing HaoLian Technology Co.,Ltd.CAN message send module is according to CAN 2.0B standard and packed by MATLAB / Simulink.WiFi communication standard is IEEE 802.11 b / g.The maximum communicationspeed is up to 54 MB / s.The protocol conversion from CAN to WiFi is realized by the hardware module and the wireless communications uses relatively secure TCP connection mode.WiFi communication is coded by C # language according to communication socket function to achieve.According to the requirements of OBD-?,the fault diagnosis system not only needs to correctly diagnose the fault code,but also needs to constrain the user's behavior.Therefore,the fault code database is established to complete the fault inquiry and sending functions.The software on remote side can access the SQL database and call the SQL operating language through ADO.NET.The fault message is send by mail to the users for warning.Finally,the signal generator from Simulink module library is used to simulate the fault signal.Then the designed diagnostic module can be verified by the simulated signal.The communication system test platform is set up to test the function and performance of the designed remote communication system.The test results show that the designed remote communication system can correctly diagnose the fault information and wirelessly transmit the message to the remote side for related processing.The communication is fast and accurate and the software function runs as expected.