基于QEPAS的汽车CO排放量检测技术研究

发布时间：2018-04-30 08:31

本文选题：汽车排放检测 + CO　；参考：《东北林业大学》2015年硕士论文

【摘要】：汽车的快速增长和普遍应用,给人们的生活和生产带来便利的同时,其排放的污染物也给我们赖以生存的环境造成严重的污染。要做好汽车排放污染物的监控与防治,首先必须严格做好汽车排放检测工作,禁止不达标的汽车上路行驶。我国从1981年就根据我国的工业水平和国情开始着手制定相应的排放法规,随着我国工业水平的不断提高,出台的排放法规越来越严格,对有害的排放物的限值要求越来越低。这样,就需要高效、可靠、检测下限越来越小和精度越来越高的检测技术与方法。石英增强光声光谱法(QEPAS)在气体检测方面具有灵敏度高、免疫外界干扰强、探测下限低、动态测量范围大和响应与入射光的波长无关等优点。采用QEPAS对汽车排放的CO检测,将为汽车排放检测提供新的思路和方法。本文以气体分子红外吸收理论为基础,选择汽车排放的CO为待测气体,找出与其它气体吸收峰无交叉干扰的吸收谱线。对石英音叉参数和石英增强光声光谱理论进行分析,采用波长调制法和谐波检测法,提高系统的信噪比和精度。利用Matlab软件模拟QEPAS检测汽车C0排放量,为试验奠定理论基础。在石英增强光声光谱理论分析的基础上设计和构建QEPAS汽车CO排放检测系统；选用可调谐DFB激光器及准直聚焦光路作为系统的光路部分；使用石英音叉和共振管作为系统的气路主要部分；采用前置放大器、电子控制单元和计算机组成系统电路部分。对QEPAS汽车CO排放检测系统激光器的波长和功率随温度及电流变化进行测试,并对调制参数进行选择；采用波长调制法对其进行标定,并对其检测下限、重复性和稳定性进行测试；结合国家标准GB 18285-2005《点燃式发动机汽车排气污染物排放限值及测量方法(双怠速法及简易工况法)》对汽车CO排放量进行检测,并将检测结果与尾气分析仪测量结果进行比较。
[Abstract]:The rapid growth and widespread application of automobiles bring convenience to people's life and production, and at the same time, the pollutants emitted by them also cause serious pollution to the environment on which we rely for survival. In order to monitor and control the emission of pollutants, the first step is to strictly monitor the emission of vehicles and prohibit vehicles that do not meet the standards required for running on the road. China began to formulate corresponding emission regulations according to the industrial level and national conditions of our country in 1981. With the continuous improvement of industrial level in China, the emission regulations are becoming more and more strict, and the limit requirements for harmful emissions are becoming lower and lower. In this way, the detection techniques and methods with high efficiency, reliability, lower detection limit and higher precision are needed. Quartz enhanced photoacoustic spectroscopy (QEPAS) has the advantages of high sensitivity, strong immunity to external interference, low detection limit, large dynamic measurement range and independent response to the wavelength of incident light in gas detection. The application of QEPAS to CO detection of automobile emissions will provide new ideas and methods for vehicle emission detection. Based on the infrared absorption theory of gas molecules, the CO emitted from automobile is selected as the gas to be measured, and the absorption spectrum without cross interference with other gas absorption peaks is found. The parameters of quartz tuning fork and the theory of quartz enhanced photoacoustic spectrum are analyzed. The signal-to-noise ratio (SNR) and accuracy of the system are improved by wavelength modulation method and harmonic detection method. The Matlab software is used to simulate QEPAS to detect the C _ 0 emission of automobile, which lays a theoretical foundation for the test. Based on the theoretical analysis of quartz enhanced photoacoustic spectroscopy, the QEPAS vehicle CO emission detection system is designed and constructed, and the tunable DFB laser and collimated focusing light path are selected as the optical path of the system. Quartz tuning fork and resonance tube are used as the main part of the system, and the preamplifier, electronic control unit and computer are used to make up the circuit of the system. The wavelength and power of the QEPAS vehicle CO emission detection system laser are measured with temperature and current, and the modulation parameters are selected, the wavelength modulation method is used to calibrate the laser, and the detection limit is measured. Repeatability and stability are tested, combined with the national standard GB18285-2005 < limit value and measurement method of exhaust pollutant emission from ignition engine (double idling method and simple working condition method) > to detect automobile CO emission, The test results were compared with those measured by tail gas analyzer.
【学位授予单位】：东北林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X831

【参考文献】