Research On Vertical Telemetry Technology Of Vehicle Exhaust And Design Of Spectrum Processing Algorithm

Along with the rapid development of the national economy and the continuous improvement of people's living standards,the motor vehicle possession in China is increasing,and motor vehicle exhaust emissions have become the main mobile pollution source of the atmosphere.It's shown in studies that within the total amount of motor vehicle pollution,exhaust emissions from the vehicles exceeding the standard should account for a large proportion.Therefore,the development of rapid detection equipment for the exhaust emissions form motor vehicles to realize the rapid identification of the road driving vehicles with excessive emissions is of great significance for the supervision of vehicle exhaust emissions.Aiming at the problem of multi-lane mutual interference in the remote sensing equipment of roadside motor vehicle exhaust,in this paper,the vertical telemetry technology for the vehicle exhaust and its spectral processing algorithm design are both researched.The main research work completed is as follows:(1)The detection method of vehicle exhaust emission is described,the principle and characteristics of the roadside horizontal and vertical telemetry system for the vehicle exhaust CO&CO2 are analyzed respectively,which shows the advantage that the vertical telemetry technology system can be expanded into multiple lanes.Then the key issues that the vertical telemetry system needs to study are analyzed.(2)The principle of tunable semiconductor laser absorption spectroscopy(TDLAS)technology is described in detail.Then telemetry experiment system for the vehicle exhaust emissions is built.With it the laser echo signals of different reflective materials are measured through experiments.The diffusion characteristics of the vehicle exhaust plume are simulated by the FLUENT software,and the relationship of the exhaust concentration dilution ratio changed with the distance between the measuring point and the exhaust pipe is analyzed.(3)The Voigt reconstruction process for the absorbance curve of the CO absorption spectroscopy is optimized.The application of Voigt linear triangular substitution model in absorption spectroscopy is proposed,the reconstruction results of absorbance curves of CO in different concentrations are used for compare with Gauss-Hermite method and another fast reconstruction model:Normalized Lorentz model,The experimental results show that the average time-consuming of the proposed triangular substitution method is 15.81%of that of the Gauss-Hermite method and 16.27%of that of the Normalized Lorentz method.(4)In this paper,an adaptive hierarchical Savitzky-Golay smoothing filter algorithm is proposed and its fitting order and sliding window size is selected adaptively.The experimental results show that after filtering the noisy CO absorption spectrum,the maximum error of the absorption peak reduces from 25.152%to 5.917%and the maximum error of the integral absorbance reduces from 18.1%to 3.9%.After filtering the noisy CO2 absorption spectrum,the maximum error of the absorption peak reduces from 12.76%to 4.72%.The maximum error of the integral absorbance reduces from 8.49%to 4.12%.(5)The control and data processing software for the vertical telemetry system of the vehicle exhaust has been developed,with which the functions of spectrum acquisition,filtering,concentration inversion,data display and preservation can be realized.The calibration and performance testing experiments of the system have been carried out,during which the telemetry experiments have been carried out on the CO and CO2 concentrations of multiple motor vehicles in different working conditions,and detection results are compared with those of the vehicle-mounted CO and CO2 concentration detection modules.Then the CO and CO2 emission laws of the motor vehicle exhaust under different working conditions have been analyzed.