Device for measuring NO2 concentration of high-sensitivity diesel engine emissions based on TDLAS technology

Abstract

The invention relates to the field of devices for measuring the NO2 concentration of high-sensitivity diesel engine emissions based on a TDLAS technology. The measurement device comprises a laser, a reference gas pool, a hollow-core optical fiber, an optical window mirror, a compressed air interface, a diesel exhaust pipe, a convergence lens, a laser detector and a data processing module. The reference gas pool is connected with the optical window mirror through the hollow-core optical fiber. The optical window mirror and the convergence lens are symmetrically distributed on two sides of the diesel exhaust pipe. The convergence lens is connected with the laser detector through the hollow-core optical fiber. According to the invention, the system structure is simplified by inserting the reference gas pool to omit a reference channel; during the operation of a diesel engine, original mechanical noise and low-frequency noise of an instrument are relatively large, which easily affects themeasurement; and the addition of the reference gas pool can effectively improve the signal-to-noise ratio of the device and improve the test sensitivity and accuracy.

Description

technical field [0001] The invention relates to the field of laser measuring devices, in particular to a high-sensitivity diesel engine emission NO sensor based on TDLAS technology. 2 The field of concentration measuring devices. Background technique [0002] With the increasingly serious global environmental problems, all countries attach great importance to the protection of the environment. In our country, environmental problems have also become a problem that restricts social development and affects the national economy and people's livelihood. In terms of air pollution, the discharge of ship power plants has always been an important problem. The Ministry of Transport also has further requirements and restrictions on the emission of pollutants from ships, which also puts forward new requirements for corresponding test methods and devices. Traditional test methods have been difficult to meet the new requirements. In the future, the test method of pollutants emitted by m...

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Problems solved by technology

However, in the actual measurement, it is not difficult to find that there are certain problems in the diesel engine emission test based on TDLAS technology. The more obvious ones include: (1) The marine diesel engine will produce a lot of vibration during the actual operation process, which will affect the testing equipment. Vibration resistance puts forward certain requirements; (2) The measurement principle based on the direct absorption method is relatively simple, but its measurement results are greatly affected by low-frequency noise, resulting in a certain limitation in accuracy; (3) If the harmonic measurement method is used, the low-frequency noise, but it also makes the structure and principle of the device more complicated, and it is not convenient to carry out experiments on diesel engines

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