Research On Vehicle Exhaust Telemetry Device Based On Differential Optical Absorption Spectroscopy

With the gradual increase of the number of motor vehicles in the city,the emission of pollutants from motor vehicle has become one of the main sources of air pollution,meanwhile has become one of the main culprits affecting people's health.In order to effectively monitor the composition of motor vehicle exhaust in real time,it has significance to develop a remote monitoring system for motor vehicle exhaust.Differential optical absorption spectroscopy(DOAS)is widely used in atmospheric environment monitoring because of its high accuracy and resolution,simultaneous measurement of multiple gases,short monitoring period and low maintenance cost.Based on the problem of air pollution and the necessity of vehicle real-time monitoring,this paper focuses on the development of vehicle exhaust UV telemetry sensing device and the performance test of the device.The main research contents are:1 ? The principle of remote measurement and the requirement for static measurement of pollutant gases in "Automobile Pollutant Emission Limits and Measurement Methods-Compilation Instructions" are analyzed.The degree and measurement index of vehicle exhaust gases can be reflected.Several detection methods of vehicle exhaust gases are analyzed and designed according to the advantages of optical detection technology.A set of vehicle telemetry device based on differential absorption spectroscopy technology is developed.The monitoring of NO and HC in vehicle exhaust provides a feasible method for simultaneous measurement of NO and HC.2?A horizontal UV telemetry device is proposed in this paper.On the basis of the integration of optical fiber transceiver and receiver,the UV pulse xenon lamp is used as the system light source.The spectrometer is developed independently and can synchronously control the xenon lamp to drive the light.It has the advantages of portability and flexibility.The telemetry system has been tested statically,including indication error,repeatability,linearity and stability,all with high correlation coefficients.Compared with the traditional DOAS telemetry system,the measurement structure is simplified and the detection performance is improved.3?A vertical telemetry device was developed for the horizontal telemetry device,furthermore its indication error,repeatability,linearity and stability were tested and compared with the horizontal structure,which was significantly improved.The system continuously monitors the exhaust pollutants NO and HC of the motor vehicle.The results show that the system measurement results are accurate and meet the real-time online monitoring requirements for vehicle exhaust.The research in this paper shows that the horizontal and vertical motor vehicle exhaust telemetry system has good test results for exhaust gas monitoring,which not only meets the national standard requirements and practical application requirements,but also has fast response time and high measurement accuracy compared with other telemetry devices.