Tail gas telemetering device based on near-infrared tunable diode laser spectrum technology

Abstract

The invention discloses a tail gas telemetering device based on a near-infrared tunable diode laser spectrum technology. The tail gas telemetering device comprises a transmitting end and a receiving end located on the same side of a road, and a reflecting end on the other side of the road; the transmitting end mainly comprises a near infrared laser and a collimating lens; the receiving end mainlycomprises a photoelectric detector DP; a data acquisition card used for generating a modulated signal and performing high-speed data sampling, wherein the modulated signal is formed by superimposing alow-frequency triangular wave signal and a high-frequency sine wave signal, and the modulated signal is input to a near infrared current drive; a computer used for analyzing received optical information; and a second harmonic signal is obtained through the operation of a digital lock-in amplifier program, and the real-time gas concentration is obtained by calculating the amplitude of the signal and parameters obtained by calibration in advance. According to the tail gas telemetering device based on the near-infrared tunable diode laser spectrum technology provided by the invention, the concentration of two gases can be measured by one-time scanning, and the complexity of a system is greatly reduced; and due to the fact that the light paths are the same, the obtained concentration ratio ofthe two gases is also more accurate.

Description

technical field [0001] The device relates to a detection technology for carbon monoxide and carbon dioxide in exhaust pollutants of passing vehicles, in particular to a remote detection device for exhaust pollutants based on near-infrared tunable diode laser spectrum technology. Background technique [0002] At present, more and more cities have air pollution problems. As one of the main causes of air pollution, the prevention and control of motor vehicle exhaust pollution in my country is facing a very severe situation. It mainly includes two reasons: first, the continuous growth of the number of motor vehicles in the country leads to a high level of total exhaust emissions; second, the pollution hazards caused by exhaust emissions of motor vehicles are particularly obvious. Therefore, strengthening the control of motor vehicle exhaust pollutants, especially strengthening the supervision of motor vehicle exhaust emissions, plays an important role in improving the air quali...

AI Technical Summary

Problems solved by technology

However, the off-axis hollow paraboloid used in this system is difficult to process and the price is high, and because the optical fiber is used to receive ultraviolet light, the output power of ultraviolet light is low, and a good signal-to-noise ratio cannot be achieved

[0005] The utility model with the patent number CN201820372366.5 discloses an integrated telemetry host, and its existing problems are: when the collimated ultraviolet light is parallel to the infrared laser, the infrared laser is collected by the optical fiber after returning, and the signal propagates in the optical fiber There are multiple modes, which will form crosstalk with each other, and eventually cause the detected signal to be affected by interference and other phenomena; when the collimated ultraviolet light is not parallel to the infrared laser, the infrared laser is converged by the off-axis parabola with the different lengths of the absorption pool The position will be offset, and fine-tuning is required for each erection

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