Vehicle-mounted motor vehicle tail gas test platform based on dynamic dilution method and sampling method

Abstract

The invention discloses a portable energy-saving vehicle-mounted motor vehicle tail gas test platform device based on a dynamic dilution method and a sampling method. Through gradual two-stage dilution, the processes of mixing, dilution, cooling and secondary pollutant formation of mobile-source tail gas when the tail gas is discharged into the atmospheric environment are simulated, and the loss of pollutants is reduced as much as possible in the processes. After the motor vehicle tail gas passes through a tail gas flow measuring system, the tail gas is mixed with zero gas at a sampling port to achieve primary dilution; dynamic dilution ratio adjustment sampling is achieved through feedback adjustment of a mass flowmeter of a dilution system on the basis of the concentration change of pollutants in the motor vehicle tail gas or the change of the working condition of an engine. In a dilution process, the motor vehicle tail gas does not pass through any air pump or any flow meter beforeentering a detection unit, so that interference is reduced. The platform can adapt to the emission characteristics of real-time working conditions of motor vehicles, improve the measurement accuracy and achieve dynamic dilution of the motor vehicle tail gas.

Description

technical field [0001] The invention belongs to the technical field of environmental protection monitoring and relates to tail gas emission monitoring technology, in particular to an on-board testing platform device and sampling method for motor vehicle exhaust gas based on a dynamic dilution method. Background technique [0002] Motor vehicle exhaust emission has become the main source of urban air pollution. The gaseous pollutants and particulate matter emitted by motor vehicles have serious adverse effects on the atmospheric environment and human health. Therefore, it is necessary to study the characteristics of motor vehicle exhaust emissions. At present, the measurement methods of motor vehicle exhaust emissions include tunnel test, remote sensing observation, bench test and actual driving test. A comprehensive comparison of the actual driving test can better reflect the real emission level of motor vehicles. The new national light motor vehicle emission standard (Natio...

AI Technical Summary

Problems solved by technology

The device introduces a dilution method to achieve the purpose of reducing the temperature and humidity of motor vehicle exhaust. However, the device uses a single-stage dilution, and the sample gas is diluted after passing through a section of sampling tube. It is necessary to provide a higher temperature for the sampling tube to keep warm and for high activity Components may be lost in the sampling tube. In addition, the device has a large volume and requires a large amount of zero air, which consumes a lot of energy. It is not suitable for the actual driving test of small cars.

In addition, because the pollutants emitted by motor vehicles fluctuate greatly with the working conditions, the system adopts fixed dilution ratio sampling and cannot adapt to the emission changes under different working conditions, resulting in large measurement errors

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