Research Of In-use Vehicle Emission Management Based On OBD

China's vehicle production and holdings are growing by leaps and bounds. Motor vehicle pollution has become a major source of urban air pollution. Against motor vehicle pollution, every country in the world are actively taking measures through the development of emission regulations and by formulating appropriate strategies to reduce the environmental impact of motor vehicle pollutants.It is significant to alert the driver to maintain the malfuctioned system when failure occurred. Considering this, lots of researches were developed upon OBD (On Board Diagnostics) which can inspect the real-time work state of emission control system.Inspection and Maintenance Program (IM) can control vehicle emission effectively, which has been proved by the implementing in foreign countries. Consequently, the combination of OBD and IM could do great for emission control. Above all, the building of in-use vehicle OBD-IM program in China would bring huge benefit for the improvement of in-use vehicle emission control.This paper studies the OBD-IM program for light-duty gasoline vehicle.This paper studies the development of OBD, and discusses the difference between OBDII and EOBD. Then, this paper researches the principle of OBD system. On the base of the above statement, this paper discusses the MIL status, DTCs, Ready code status and diagnoses tools.This paper also studies the OBD-IM program of American, labors the develop course, inspection content and judge criterion. After that, analyzes the inspection data collected from Wisconsin in American.The conclusions are listed below:Ready code status check is quite significant in the OBD-IM program; There is kind of relationship between MIL status and vehicle mileage; OBDIII is the develop trend for OBD-I/M check.At last, also the most important, this paper introduces the OBD-IM program of Beijing, which includes the regulation for inspection, inspection content and the test result analyse. Finally, gives the implement suggestion for OBD-IM program of China listed below: Establish the specific standard for diagnose connecting port. Enhance the training for technicians in vehicle check field. Develop the suitable diagnose tools based on China regulations. Strenthens the management on OBD-IM program. Collect more effective check data, build the database for OBD check.