CN109655317B - Motor vehicle tail gas vehicle-mounted test platform based on dynamic dilution method and sampling method - Google Patents
Motor vehicle tail gas vehicle-mounted test platform based on dynamic dilution method and sampling method Download PDFInfo
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- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0011—Sample conditioning
- G01N33/0018—Sample conditioning by diluting a gas
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- G01N2001/2264—Sampling from a flowing stream of gas with dilution
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Abstract
The invention discloses a portable energy-saving vehicle-mounted test platform device for motor vehicle tail gas based on a dynamic dilution method and a sampling method. The tail gas of the motor vehicle passes through the tail gas flow measurement system and then is mixed with zero gas at a sampling port to realize primary dilution; the dilution ratio dynamic adjustment sampling is realized by feeding back and adjusting the mass flowmeter of the dilution system through the concentration change of pollutants in the tail gas of the motor vehicle or the working condition change of the engine; in the dilution process, the tail gas of the motor vehicle does not pass through any air pump and flow meter before entering the detection unit, so that the interference is reduced. The invention can adapt to the real-time working condition emission characteristic of the motor vehicle, improve the measurement accuracy and realize the dynamic dilution of the tail gas of the motor vehicle.
Description
Technical Field
The invention belongs to the technical field of environmental protection monitoring, relates to a tail gas emission monitoring technology, and particularly relates to a vehicle-mounted test platform device for motor vehicle tail gas based on a dynamic dilution method and a sampling method.
Background
The exhaust emission of motor vehicles has become a main source of urban atmospheric pollution at present, and the exhaust gaseous pollutants and particulate matters of motor vehicles have serious adverse effects on the atmospheric environment and human health, so that the research on the exhaust emission characteristics of motor vehicles is necessary. The current motor vehicle exhaust emission measurement mode comprises tunnel test, remote sensing observation, bench test and actual driving test. The comprehensive comparison actual running test can reflect the actual emission level of the motor vehicle, and the new national light motor vehicle emission standard (Guohu) also provides the actual running test requirement of the motor vehicle.
Because the motor vehicle exhaust has the characteristics of high temperature, high humidity and the like, most instruments cannot directly measure the motor vehicle exhaust, and the motor vehicle exhaust is required to be measured after being treated. At present, the tail gas treatment of the motor vehicle is mainly carried out by a condensation water removal mode, for example, the principle of a pretreatment system of the American Sensors company is as follows: and (3) carrying out low-temperature condensation water removal on the tail gas of the motor vehicle after heating the sampling tube, then carrying out secondary drying treatment, and entering a detection unit after water removal through a two-stage drying process. The condensation water removal process in the treatment process can cause part of the motor vehicle emission pollutants to be dissolved in the condensed water, so that the components to be detected are lost.
The Chinese patent (publication No. CN 103076429A) relates to a motor vehicle tail gas measuring device, which is mainly used for collecting particulate matters and VOCs samples. The device introduces a dilution method to achieve the aim of reducing the temperature and humidity of tail gas of the motor vehicle, but adopts single-stage dilution, and the sample gas is diluted after passing through a section of sampling tube, so that the sampling tube is required to be subjected to heat preservation at a higher temperature, and high-activity components are possibly lost in the sampling tube. In addition, because the pollutant discharged by the motor vehicle greatly changes along with the fluctuation of working conditions, the system cannot adapt to the discharge change under different working conditions by adopting fixed dilution ratio sampling, and the measurement error is larger.
With the increasing strictness of the national emissions standards for motor vehicles, new emissions standards for motor vehicles (state 6) put forward actual driving emissions test requirements for motor vehicles. In order to meet the road test of the actual working condition of the motor vehicle, a portable and low-energy-consumption tail gas dynamic dilution system is designed.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a portable energy-saving vehicle-mounted test platform device for motor vehicle tail gas based on a dynamic dilution method and a sampling method, which are used for simulating the mixed dilution cooling and secondary pollutant forming process of the tail gas of a mobile source discharged into the atmosphere environment, and reducing the loss of pollutants. The invention can adapt to the real-time working condition emission of the motor vehicle by the dynamic dilution function, and improves the measurement accuracy.
The technical scheme provided by the invention is as follows:
A vehicle-mounted test platform device for motor vehicle tail gas based on a dynamic dilution method comprises a vehicle-mounted OBD decoder (On Board Diagnostics, a vehicle-mounted automatic diagnosis system), a motor vehicle tail gas flow measurement system, a heating and heat-preserving sampling tube and a tail gas dynamic dilution system. The vehicle-mounted OBD decoder is used for reading real-time engine parameters; the motor vehicle tail gas flow measuring system consists of a stainless steel tube, a temperature sensor, a pitot tube flowmeter and a differential pressure sensor; the stainless steel tube in the motor vehicle exhaust gas flow measuring system is heated and insulated by using the exhaust waste heat of the motor vehicle, so that the condensation loss of the exhaust gas on the inner wall is reduced; the heating sampling tube consists of a polytetrafluoroethylene tube, a heating and heat-preserving layer and a temperature sensor, and can be heated and preserved to 60 ℃ so as to reduce the condensation loss of pollutants; the tail gas dynamic dilution system comprises a mass flowmeter, a primary diluter, a secondary diluter, an electromagnetic valve, a temperature and humidity sensor and an air pump, wherein the primary diluter and the secondary diluter comprise a sample gas inlet, a zero gas inlet and a dilution cavity; and a mass flowmeter is arranged before the zero gas enters the primary diluter and the secondary diluter to control the flow, so that the flow is accurately controlled.
Aiming at the dynamic dilution sampling device for the motor vehicle tail gas, further, the inner wall of the stainless steel pipe of the motor vehicle tail gas flow measurement system adopts a Teflon plating layer to prevent the adsorption and degradation of active components in pollutants;
The motor vehicle tail gas flow measurement system comprises a stainless steel cylinder with the overall length of 650mm and the diameter of 63.5mm, wherein a temperature sensor is respectively arranged at a position 60mm and a position 360mm away from an inlet of the stainless steel cylinder, a pitot tube flowmeter is arranged at a position 260mm in an open pore manner, and two reserved sampling ports are arranged at a position 410mm and a position 450 mm;
the Pitot tube flowmeter adopts an S-shaped Pitot tube; the differential pressure sensor adopts a high-precision differential pressure transmitter; compared with an L-shaped pitot tube, the S-shaped pitot tube has the advantage of being less prone to blockage.
By utilizing the vehicle-mounted test platform for the tail gas of the motor vehicle based on the dynamic dilution method, the invention also provides a dynamic secondary dilution sampling method for the tail gas of the motor vehicle, and the mixed dilution cooling and secondary pollutant forming process of the tail gas of the mobile source discharged into the atmosphere environment is simulated through two-stage gradual dilution; the tail gas (sample gas) of the motor vehicle passes through the tail gas flow measurement system and then enters the primary diluter at the reserved sampling port to be mixed with zero gas so as to realize primary dilution, and the diluted sample gas enters the heating insulation sampling tube. In order to prevent the rapid cooling and condensing of the sample gas after the primary dilution, a progressive dilution method (two-stage dilution) is adopted, and a primary diluter and a sampling tube of the tail gas dynamic dilution system are heated and insulated (to 60 ℃). The pollutant concentration in the tail gas of the motor vehicle or the engine working condition change (such as engine rotating speed data) read by the vehicle-mounted OBD decoder is fed back to the dynamic dilution system to realize dynamic dilution ratio adjustment sampling; in the whole dilution process, the tail gas of the motor vehicle does not pass through any air pump and flow meter before entering the detection unit, so that the interference and loss of components to be detected by the air pump and the flow meter are prevented. The method specifically comprises the following steps:
1) The motor vehicle tail gas enters a motor vehicle tail gas flow measuring system through an exhaust pipe, the exhaust temperature and the exhaust flow are measured in the flow measuring system, two sampling ports are reserved, the simultaneous measurement of particulate matters and gaseous pollutants is met, and the whole flow measuring system is insulated by utilizing the waste heat of the motor vehicle tail gas;
2) Designing a structure of a motor vehicle tail gas flow measurement system, and sequentially arranging and installing a first temperature sensor, a pitot tube flowmeter, a second temperature sensor, a first reserved sampling port and a second reserved sampling port in a stainless steel cylinder; the structure of the motor vehicle tail gas flow measurement system completely meets the related measurement technical requirements of GB 18352.6;
In the specific implementation, the motor vehicle exhaust flow measurement system main body comprises a stainless steel cylinder with the overall length of 650mm and the diameter of 63.5mm, temperature sensors are respectively arranged at the positions 60mm and 360mm away from an inlet of the stainless steel cylinder, a pitot tube flowmeter is arranged at a position of 260mm in an open pore manner, and two reserved sampling ports are arranged at the positions 410mm and 450 mm.
3) After the tail gas exhausted by the motor vehicle passes through the motor vehicle tail gas flow measuring system, the tail gas is directly mixed with zero gas in a primary diluter of the tail gas dynamic diluting system at a sampling port, so that possible loss of the sample gas from the sampling port to a primary diluter pipeline is eliminated. The tail gas dynamic dilution system comprises a heating sampling tube, a mass flowmeter, a primary diluter, a secondary diluter, an electromagnetic valve, a temperature and humidity sensor and an air pump;
In the specific implementation, in order to prevent the tail gas from condensing in the primary diluter and the sampling tube, the primary diluter and the sampling tube are heated and kept at 60 ℃. And after primary dilution, the temperature and humidity of the sample gas are measured, so that the humidity is ensured to be within a reasonable range, and liquid condensation water is not generated.
4) The tail gas is divided into two paths after primary dilution, and one path directly enters the first detection unit; the other path of the sample gas enters a secondary diluter, the sample gas is subjected to secondary cooling and dehumidifying in the secondary diluter to enable the temperature and humidity of the sample gas to be close to ambient air, and the sample gas enters another detection unit (a second detection unit) after being subjected to secondary dilution.
5) The power of the whole set of dilution system is at the rear end of the dilution gas; when the diluent gas outlet is not connected with the detection unit, the bypass flow is adjusted by closing the corresponding pipeline electromagnetic valve to control the diluent ratio.
For the pollutant detection unit capable of rapidly responding, the pollutant concentration signal of the detection unit is fed back to the bypass mass flowmeter, and the dilution ratio is dynamically adjusted in two stages by adjusting the two bypass flows, so that the dynamic dilution sampling of the tail gas of the motor vehicle is realized; when the pollutant concentration response of the detection unit is slower, the engine rotating speed read by the vehicle-mounted OBD decoder is fed back to the bypass mass flow, and the dynamic adjustment of the dilution ratio is realized by adjusting the bypass flow, namely the dynamic dilution sampling of the tail gas of the motor vehicle is realized.
The dynamic dilution sampling method for the motor vehicle tail gas keeps the temperature of the motor vehicle tail gas flow measurement system, measures the temperature of the tail gas at the inlet and the outlet of the motor vehicle tail gas flow measurement system, and ensures that the motor vehicle tail gas is maintained in an in-situ state before entering the dilution system; the condensation loss of pollutants is reduced through two-stage dilution; and through dynamic adjustment of the dilution ratio, the concentration of the pollutant discharged by the tail gas under each working condition of the motor vehicle is measured more accurately.
Compared with the prior art, the invention has the beneficial effects that:
The invention provides a portable energy-saving motor vehicle tail gas flow measuring and dynamic diluting sampling method and device, which have the following main technical advantages compared with the prior art:
1. mixing the sample gas with the primary dilution gas at the outlet of the tail gas flowmeter, reducing the interference and loss of the sampling pipeline on pollutants and reducing the heat tracing energy consumption of the sampling pipeline;
2. The sample gas is subjected to two-stage dilution treatment, so that the contaminant condensation loss caused by the rapid cooling of one-stage dilution is prevented.
3. The mass flow meters are respectively added at the zero gas inlet and the diluent gas outlet of the primary diluter and the secondary diluter to control the zero gas quantity entering the primary diluter and the secondary diluter, and the dilution ratio can be conveniently adjusted by adjusting the bypass flow of the outlet;
4. The heating and heat preservation of the sampling pipeline are adopted, and the natural dilution process in the pollutant discharge process is simulated, so that the interference and loss of components to be tested in the dilution process are reduced to the greatest extent without physical and chemical drying treatment in the whole dilution process;
5. the bypass flow is regulated by measuring the concentration of pollutants or feeding back the real-time working condition of the engine so as to realize dynamic dilution;
6. The heat tracing temperature of the sampling pipeline after primary dilution is not required to be too high, the required zero air quantity is smaller, a large air compressor is not required to provide compressed air, and the energy consumption is saved;
7. The whole diluting device is smaller and more portable by reducing the volume of the diluting cavity, and meanwhile, the diluting device can be conveniently installed and transported on a small-sized motor vehicle.
Drawings
FIG. 1 is a schematic diagram of the composition structure of a dynamic dilution sampling device for motor vehicle exhaust provided by an embodiment of the invention;
FIG. 2 is a dimensional view of an automotive exhaust flowmeter structure provided in an embodiment of the present invention;
1-motor vehicle exhaust pipe in FIGS. 1-2; 2-stainless steel clamp; 3-a temperature sensor; 4-a motor vehicle exhaust flow measurement system body; 5-pitot tube flow meter; 6-a temperature sensor; 7-a first reserved sampling port; 8-a second reserved sampling port; 9-a dilution system; 10-heating the sampling tube; 11-a mass flowmeter; 12-a primary diluter; 13, a temperature and humidity sensor; 14-a mass flowmeter; 15-a pressure sensor; 16-high pressure zero gas; 17-a secondary dilution chamber; 18-a temperature and humidity sensor; 19-a mass flowmeter; 20-a mass flowmeter; 21-an electromagnetic valve; 22-an electromagnetic valve; 23-an air pump; 24-on-board OBD decoder; 25—a temperature sensor interface; 26-pitot tube flow meter interface; 27—a temperature sensor interface;
Detailed Description
The invention is further described by way of examples in the following with reference to the accompanying drawings, but in no way limit the scope of the invention.
The invention provides a portable energy-saving dynamic dilution sampling method and a vehicle-mounted test platform device for motor vehicle tail gas based on the dynamic dilution method. The device comprises a vehicle-mounted OBD decoder, a motor vehicle tail gas flow measuring system, a heating sampling tube and a tail gas dynamic diluting system; the vehicle-mounted OBD decoder is connected with a data interface of the engine of the motor vehicle and reads real-time working condition data of the engine; the motor vehicle tail gas flow measurement system comprises a stainless steel tube, a temperature sensor, a pitot tube flowmeter and a differential pressure sensor; the tail gas dynamic dilution system comprises a mass flowmeter, a primary diluter, a secondary diluter, an electromagnetic valve, a temperature and humidity sensor and an air pump. Only zero air dilution is carried out on the tail gas of the motor vehicle to meet the detection requirement of a detection unit, so that the pollutant loss caused by physical and chemical drying is reduced; the sampling flow is calculated by the total flow and the dilution flow, so that the influence of an air pump and a mass flowmeter is avoided; dynamic dilution is achieved through concentration feedback and rapid response of the mass flowmeter.
In specific implementation, the vehicle-mounted test platform device for the tail gas of the motor vehicle based on the dynamic dilution method mainly comprises the following components: two parts of tail gas flow measuring and tail gas dynamic diluting devices of motor vehicles. Fig. 1 shows the structure of the device. The motor vehicle tail gas pipe is fixedly connected with the motor vehicle tail gas flow measuring system through a clamp, and the motor vehicle tail gas flow measuring system 4 comprises a pitot tube flowmeter 5, temperature sensors 3 and 6 and sampling ports 7 and 8. The motor vehicle exhaust gas flow measurement system 4 is provided with two reserved sampling ports (a first reserved sampling port 7 and a second reserved sampling port 8 are respectively used for sampling particulate matters and gaseous pollutants), so that the simultaneous sampling of the particulate matters and the gaseous pollutants is satisfied. FIG. 2 is a dimensional illustration of an automotive exhaust flow meter structure provided by an embodiment of the invention, as shown, with the left side being a front view and the right side being a side view; wherein the total length of the flow measurement system is 650mm, and the diameter is 63.5mm; the tail gas is directly mixed with the primary dilution gas at the sampling port, and the mixed sample gas enters the secondary diluter through the sampling tube 10, and the heating sampling tube 10 is heated and kept at the temperature of 60 ℃. The dilution system comprises a high-pressure zero gas, a primary dilution mixing cavity, a secondary dilution mixing cavity, a mass flowmeter, a temperature and humidity sensor, an air pump, an electromagnetic valve and the like.
When the vehicle-mounted test platform for the tail gas of the motor vehicle based on the dynamic dilution method works, the temperature and the humidity of the tail gas are monitored in real time after the tail gas is subjected to primary dilution, and the humidity of the sample gas after the primary dilution is ensured to be less than 60 percent. The flow rate of the primary dilution zero gas is controlled to be Q1 through a mass flowmeter 11, and the flow rate of the secondary dilution zero gas is controlled to be Q2 through a mass flowmeter 14. The primary dilution bypass mass flowmeter 19 and the detection unit 1 are controlled to have a total flow rate Q3. The total flow through the control of the secondary dilution bypass mass flowmeter 20 and the sensing unit 2 is approximately Q4 (dynamically adjustable). The primary dilution ratio is (Q4-Q2 + Q3)/(Q4-Q2 + Q3-Q1), and the secondary dilution ratio is equal to Q4/(Q4-Q2). When the first-level dilution gas or the second-level dilution gas is not connected with a monitoring instrument, the total flow is regulated by closing the corresponding pipeline electromagnetic valves 22 and 23 and simultaneously regulating the corresponding bypass mass flow meters (19 and 20), and the dilution ratio is controlled within the required range. The tail gas flow measurement and dynamic dilution sampling of the motor vehicle are realized.
It should be noted that the purpose of the disclosed embodiments is to aid further understanding of the present invention, but those skilled in the art will appreciate that: various alternatives and modifications are possible without departing from the spirit and scope of the invention and the appended claims. Therefore, the invention should not be limited to the disclosed embodiments, but rather the scope of the invention is defined by the appended claims.
Claims (10)
1. A dynamic dilution sampling method for motor vehicle tail gas is characterized in that real-time working condition data of a motor vehicle engine are read through a vehicle-mounted OBD decoder; simulating a mixed dilution cooling and secondary pollutant formation process of the tail gas of the mobile source discharged to the atmosphere environment through two-stage gradual dilution; the tail gas of the motor vehicle passes through the tail gas flow measurement system and then is mixed with zero gas at a sampling port to realize primary dilution; the dilution ratio dynamic adjustment sampling is realized by the feedback adjustment of the mass flowmeter of the dilution system through the concentration change of pollutants in the tail gas of the motor vehicle or the real-time working condition change of the engine; in the dilution process, the tail gas of the motor vehicle does not pass through any air pump and flow meter before entering the detection unit; the dynamic dilution sampling method for the tail gas of the motor vehicle comprises the following steps: 1) The method comprises the steps that motor vehicle tail gas enters a motor vehicle tail gas flow measuring system through an exhaust pipe, the exhaust temperature and the exhaust flow are measured by the flow measuring system, two sampling ports are reserved for simultaneously measuring particulate matters and gaseous pollutants, and the flow measuring system is insulated by utilizing the waste heat of the motor vehicle tail gas;
2) Designing a structure of a motor vehicle tail gas flow measurement system, and sequentially installing a first temperature sensor, a pitot tube flowmeter, a second temperature sensor, a first reserved sampling port and a second reserved sampling port in a stainless steel cylinder;
3) The motor vehicle tail gas enters a tail gas dynamic dilution system after passing through a motor vehicle tail gas flow measurement system; the tail gas dynamic dilution system comprises a mass flowmeter, a primary diluter, a secondary diluter, an electromagnetic valve, a temperature and humidity sensor and an air pump; firstly, directly mixing the tail gas of the motor vehicle with zero gas in a primary diluter at a sampling port;
4) The tail gas is subjected to primary dilution, then is divided into two paths through a heating heat-preserving sampling tube, and one path directly enters a detection unit; the other path enters a secondary diluter for secondary dilution and then enters another detection unit; performing secondary dilution on the tail gas to enable the temperature and the humidity of the tail gas to be close to the ambient air condition;
5) The power sampled by the tail gas dynamic dilution system is positioned at the rear end of the dilution gas; when the dilution gas outlet is not connected with the detection unit, the bypass flow is adjusted by closing the corresponding pipeline electromagnetic valve to control the dilution ratio, so that the dynamic adjustment of the dilution ratio is realized;
The method specifically comprises the following steps: for a detection unit for rapidly responding to pollutants, the concentration signal of the pollutants is fed back to the bypass mass flowmeter through the detection unit, and the two-stage dynamic adjustment of the dilution ratio is realized by adjusting the two bypass flows; for a detection unit with slow pollutant concentration response, the engine rotating speed read by the vehicle-mounted OBD decoder is fed back to the bypass mass flow, and the dynamic adjustment of the dilution ratio is realized by adjusting the bypass flow; through the steps, dynamic dilution sampling of the tail gas of the motor vehicle is realized, so that the method is suitable for real-time working condition emission of the motor vehicle, and the accuracy of measuring the concentration of pollutants in the tail gas emission under each working condition of the motor vehicle is improved.
2. The method for dynamically diluting and sampling motor vehicle exhaust according to claim 1, wherein the structure of the motor vehicle exhaust flow measurement system designed in the step 2) meets the technical requirements of GB18352.6 related measurement.
3. The method for dynamic dilution and sampling of motor vehicle exhaust according to claim 2, wherein the motor vehicle exhaust flow measurement system comprises a stainless steel cylinder with an overall length of 650mm and a diameter of 63.5mm, temperature sensors are respectively installed at a distance of 60mm and 360mm from the inlet of the stainless steel cylinder, a pitot tube flowmeter is installed at a distance of 260mm from the inlet of the stainless steel cylinder, and two reserved sampling ports are respectively installed at a distance of 410mm and 450mm from the inlet of the stainless steel cylinder.
4. The method for dynamically diluting and sampling the tail gas of the motor vehicle according to claim 1, wherein in the step 3), both the primary diluter and the sampling tube are heated and kept at 60 ℃; and after primary dilution, the temperature and humidity of the sample gas are measured, so that the tail gas is prevented from being condensed by water vapor caused by rapid cooling of primary dilution.
5. The method for dynamically diluting and sampling the tail gas of the motor vehicle according to claim 1, wherein in the step 5), the pollutant concentration of the detection unit or the working condition data of the engine are fed back to the bypass mass flowmeter, and the dynamic dilution ratio adjustment is realized by adjusting the bypass flow, so that the dynamic dilution and sampling of the tail gas of the motor vehicle is realized.
6. A vehicle-mounted test platform for motor vehicle tail gas based on a dynamic dilution method by adopting the dynamic dilution sampling method for motor vehicle tail gas according to claim 1, which is characterized by comprising a vehicle-mounted OBD decoder, a motor vehicle tail gas flow measuring system, a heating and heat preserving sampling tube and a tail gas dynamic dilution system;
The vehicle-mounted OBD decoder is connected with the motor vehicle engine data interface and is used for reading real-time working condition data of the engine;
The motor vehicle tail gas flow measurement system comprises a stainless steel tube, a temperature sensor, a pitot tube flowmeter and a differential pressure sensor; the stainless steel tube is heated and insulated by utilizing exhaust waste heat of the motor vehicle, so that condensation loss of tail gas on the inner wall is reduced;
The heating and heat-preserving sampling tube comprises a polytetrafluoroethylene tube, a heating and heat-preserving layer and a temperature sensor, and can be used for heating and heat preservation, so that the condensation loss of pollutants is reduced;
The tail gas dynamic dilution system comprises a mass flowmeter, a primary diluter, a secondary diluter, an electromagnetic valve, a temperature and humidity sensor and an air pump, wherein the primary diluter and the secondary diluter comprise a sample gas inlet, a zero gas inlet and a dilution cavity; and a mass flowmeter is arranged before the zero gas enters the primary diluter and the secondary diluter to control the flow, so that the flow is accurately controlled.
7. The vehicle-mounted test platform for the tail gas of the motor vehicle based on the dynamic dilution method according to claim 6, wherein the inner wall of the stainless steel tube of the tail gas flow measuring system of the motor vehicle is coated with a Teflon coating, so that the adsorption and degradation of active components in pollutants are prevented.
8. The vehicle exhaust on-board test platform based on the dynamic dilution method according to claim 6, wherein the vehicle exhaust flow measurement system comprises a stainless steel cylinder with an overall length of 650mm and a diameter of 63.5 mm; and a temperature sensor, a pitot tube flowmeter and a reserved sampling port are respectively arranged in the stainless steel cylinder.
9. The vehicle-mounted test platform for the tail gas of the motor vehicle based on the dynamic dilution method according to claim 8, wherein the temperature sensors are respectively arranged at the positions 60mm and 360mm away from the inlet of the stainless steel cylinder, the pitot tube flowmeter is arranged at the position 260mm, and two reserved sampling ports are arranged at the positions 410mm and 450 mm.
10. The vehicle-mounted test platform for motor vehicle tail gas based on a dynamic dilution method according to claim 6, wherein the pitot tube flowmeter adopts an S-shaped pitot tube; the differential pressure sensor adopts a high-precision differential pressure transmitter.
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| CN110531036A (en) * | 2019-09-30 | 2019-12-03 | 华南理工大学 | Motor-vehicle tail-gas real-time detecting system |
| CN112629929B (en) * | 2020-12-11 | 2021-10-08 | 山东大学 | Motor vehicle tail gas sampling device and tail gas detection system |
| CN114558512A (en) * | 2022-03-07 | 2022-05-31 | 西安多普多信息科技有限公司 | Volatile organic compound removing device and method |
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