Design Of An Improved Vehicle Exhaust Detection System

Due to the rapid development of China's automobile industry,exhaust pollution problems caused by the use of a large number of cars has affected every aspect of our lives,in order to reduce exhaust pollution,improve the ecological environment,fast and accurate detection of the concentration value of the gas pollution is imminent.This paper first analyzes the principles and methods of vehicle exhaust detection at home and abroad.Combined with the development trend of exhaust detection equipment,an improved vehicle exhaust detection system is designed for the current vehicle exhaust detection equipment with large error,high cost and complex operation.Among them,the concentration of CO,CO2 and HC is detected by the principle of the non spectral infrared absorption(NDIR).After determining the functional requirements of the system,the overall framework of the system is given.In terms of software and hardware design,the system uses STM32 Series MCU as the main controller,and designs peripheral circuits,including data storage module,key and display module,data communication module,sensor module and analog-to-digital conversion module.The human-computer interaction mode of the detection system is a graphical interactive mode,which is realized by the ?c GUI system,and the interface of the design is simple and intuitive.The system can realize idle speed measurement,dual idle speed measurement and data management and other functions.In the aspect of data processing,by inputting different concentration to the detection channel,calibration gas concentration,and the measured gas concentration and multi channel voltage ratio data fitting,the function relationship between the two,and this relation is written to the testing procedures,can introduce different anti voltage ratio the gas concentration.In this paper,the relationship between temperature and gas concentration is measured at different temperatures,and the detection error is calculated and the system is compensated for the temperature.Finally,the performance test and error analysis of the system are carried out.The automobile exhaust detection device designed in this paper has the advantages of small data error,convenient operation,good economy,good portability and so on.