Research And Development Of Vehicle OBD Emissions Testing System

With the rapid economic development,people's living standards continue to improve.Transportation like cars,has entered the household,led the development of the automotive industry.Car ownership and abroad have gradually increased vehicle production also increased steadily.However,in providing people with convenient car and also accompanied by alarming environmental problems.Vehicle emissions within the city has become one of the incentives decline in air quality and even the formation of haze.So for control and detection technology has become a hot car exhaust emissions in recent years,domestic and foreign regulations also increasingly harsh.Based on the analysis of existing automobile exhaust gas detector based on proposed exhaust gas analysis of vehicle OBD diagnosis to achieve its design of vehicle exhaust gas analysis.In the design of instruments,exhaust gas analysis using infrared absorption method to complete exhaust gas CO,CO2,NOx and the concentration of CH measuring using electrochemical measurement of O2.OBD Diagnostics section complete with PC through RS232 computer communication,to read the required engine parameters in real time.Through the MFC programming,building PC software interfaces,by actual measurement data,combined with the quality rate of conversion rules,achieve real-time monitoring of the quality of vehicle exhaust emission rates and curves.Hardware design of instrument circuits section,STM32 module is used as main chip for data storage and communication modules and digital-analog conversion principles and working methods are introduced,according to system requirements the power scheme selected.In the PCB in the process of drawing,in order to be reasonable,focused on the principles of layout and routing rules.Software make full use of powerful computational advantage,data integration and calculation.The issue of car exhaust gas analyzer design has mobility,portable,real-time characteristics.After the design is complete,respectively in the three vehicles for a duplicate vehicle tested,analyzed the results and judge.Finally in order to verify the accuracy of equipment conversion principle,using Eddy current dynamometer exhaust Analyzer combines traditional,complete sets of experiments,data integration,by error analysis,verify the accuracy of the instrument.The design of vehicle tail gas Analyzer with mobile,portable,real-time and so on.