A method and device for testing non-exhaust particulate matter emissions of new energy vehicles

Abstract

The present invention relates to the field of vehicle testing technology, and specifically, to a method and device for testing non-exhaust particulate matter emissions of new energy vehicles. In the device, the new energy vehicle travels on the chassis dynamometer in the closed chamber according to specified working conditions; multiple hair dryers blow the bottom and surrounding air of the new energy vehicle to the collection device at the top of the closed chamber at a specified wind speed; a first filter device is set on the top of the closed chamber, and the atmosphere is connected through the first filter device to keep the air pressure in the closed chamber constant; the working conditions of the new energy vehicle are changed, and the controller collects the weight of the first filter device in real time through a weighing device during the test; and the non-exhaust particulate matter emission data under each working condition is obtained. The present invention guides the wind speed of the hair dryer through the weight change rate of the first filter device, which can improve the particle collection efficiency, and can also find the optimal wind speed and save the power loss of the hair dryer.

Description

Technical Field

[0001] The present invention relates to the field of vehicle testing technology, and in particular to a method and device for testing non-exhaust particulate matter emissions of a new energy vehicle. Background Art

[0002] Mobile sources, mainly motor vehicles, have become an important source of urban atmospheric particulate matter, seriously affecting urban air quality and endangering public health. Motor vehicle particulate matter emissions include not only exhaust emissions, but also non-exhaust emissions such as brake wear, tire wear, road wear, and road dust. Light vehicles are the main component of motor vehicles and contribute greatly to motor vehicle particulate matter emissions. Non-exhaust particulate matter emissions in atmospheric emissions have become the main source of emissions. Among non-exhaust particulate matter, tire wear particles are tiny particles produced by friction between tires and the ground when vehicles are driving. They are an important part of non-exhaust emissions and an important source of particulate matter in the atmosphere. At the same time, brake wear is considered to be the most important source of non-exhaust particulate matter emissions from motor vehicles.

[0003] Under the current trend of light vehicles gradually electrifying, people often only focus on the zero-emission feature of new energy vehicles. However, this feature also leads to the non-exhaust emission sources such as brake wear and tire wear particles of new energy vehicles becoming the main particulate matter emission components, which cannot be ignored. However, there is currently insufficient understanding of the potential problems of its non-exhaust particulate matter emissions. Compared with traditional fuel vehicles, new energy vehicles have large torque and good acceleration performance, which may lead to greater friction between the tires and the ground, thereby generating more tire wear particles; in addition, due to the presence of batteries, new energy vehicles are usually heavier than traditional fuel vehicles, which is also an important factor affecting the emission of non-exhaust particulate matter. At the same time, the brake recovery system of new energy vehicles is also an important reason for affecting the emission of brake wear particles. Therefore, conducting related testing and research on non-exhaust particulate matter of new energy vehicles is a research hotspot.

[0004] In the current related test methods, the brake exhaust particulate matter is generally collected by setting a collection cover on the wheel hub, but this method cannot test the non-exhaust particulate matter emissions such as tire wear. Moreover, the existing technology also lacks research on test conditions aimed at reducing non-exhaust emissions. Summary of the invention

[0005] The purpose of the present invention is to provide a non-exhaust particulate matter emission testing method and device for new energy vehicles, so as to realize vehicle-level testing of non-exhaust particulate matter, and at the same time test the non-exhaust particulate matter emission data under different test conditions; by guiding the wind speed of the hair dryer through the weight change rate of the first filter device, the particle collection efficiency can be improved, and the optimal wind speed can also be found, saving the power loss of the hair dryer.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a non-exhaust particulate matter emission test device for a new energy vehicle, comprising: a chassis dynamometer, a closed chamber, a non-exhaust particulate matter collection device, a first filtering device, a second filtering device, a weighing device, a non-exhaust particulate matter analysis device, a plurality of blowers and a controller;

[0008] The new energy vehicle is driven on the chassis dynamometer in the closed room according to the specified test conditions; the specified conditions include driving conditions at different power levels or different ambient temperatures;

[0009] A plurality of blowers blow the bottom and surrounding air of the new energy vehicle toward the collecting device at the top of the closed chamber at a specified wind speed;

[0010] A first filter device is disposed on the top of the closed chamber, and the first filter device absorbs non-exhaust particulate matter in the closed chamber and is connected to the atmosphere to keep the air pressure in the closed chamber constant;

[0011] The test condition of the new energy vehicle is changed, and the controller collects the weight of the first filter device in real time through a weighing device during the test, and if the weight growth rate is higher than a set threshold, the wind speed of the hair dryer is increased until the weight growth rate is lower than the set threshold;

[0012] Under each operating condition, the components of the particulate matter collected by the collecting device are analyzed by an analyzing device; the collected particulate matter is filtered and weighed by the second filtering device, and non-exhaust particulate matter is retained to obtain non-exhaust particulate matter emission data under each test condition.

[0013] The present invention also provides a new energy vehicle non-exhaust particulate matter emission test method, which is applicable to any new energy vehicle non-exhaust particulate matter emission test device, and the method comprises:

[0014] The new energy vehicle is driven on the chassis dynamometer in the closed room according to the specified test conditions; the specified conditions include driving conditions at different power levels or different ambient temperatures;

[0015] The test conditions of the new energy vehicle are changed. During the test, the weight of the first filter device is collected in real time by a weighing device. If the weight growth rate is higher than a set threshold, the wind speed of the hair dryer is increased until the weight growth rate is lower than the set threshold.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention provides a vehicle-level non-exhaust particulate matter testing device and method, and the whole vehicle is placed in a closed room to collect non-exhaust particulate matter. By arranging multiple hair dryers in the closed room, the bottom and surrounding air of the new energy vehicle are blown to the collection device at the top of the closed room, ensuring that all non-exhaust particulate matter can be fully collected. A first filter device is arranged on the top of the closed room, and the atmosphere is connected through the first filter device to keep the air pressure in the closed room constant during blowing, and due to the adsorption effect of the first filter device, the particles are prevented from leaking out. The new energy vehicle first drives according to the specified test conditions and changes the conditions to obtain emission data under each test condition. The weight growth rate of the first filter device indicates the growth rate of the particles in the closed room. If the growth is relatively fast, it means that a large amount of particles are retained in the closed room and have not been blown out. Then, the specified wind speed of the hair dryer is increased in order to blow out the particles in the closed room as soon as possible. The present invention guides the wind speed of the hair dryer through the weight change rate of the first filter device, which can improve the particle collection efficiency, find the optimal wind speed, and save the power loss of the hair dryer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a structural schematic diagram of a non-exhaust particulate matter emission test device for a new energy vehicle provided by an embodiment of the present invention;

[0020] Figure 2 It is a flow chart of a method for testing non-exhaust particulate matter emissions of a new energy vehicle provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0022] Example 1

[0023] This embodiment provides a non-exhaust particulate matter emission test device for new energy vehicles, which is used to test the non-exhaust particulate matter data of the whole vehicle under different test conditions to determine the test condition with the least amount of non-exhaust particulate matter. Figure 1 The device provided in this embodiment includes: a chassis dynamometer, a closed chamber, a non-exhaust particulate matter collection device, a first filtering device, a second filtering device, a weighing device, a non-exhaust particulate matter analysis device, multiple blowers and a controller.

[0024] The new energy vehicle is driven on the chassis dynamometer in the closed room according to the specified test conditions. The specified test conditions include driving conditions at different power levels or different ambient temperatures. For example, conditions with the same braking recovery strategy and the same test ambient temperature at different power levels, and conditions with the same power level and the same braking recovery strategy at different ambient temperatures.

[0025] The vehicle is driven on a chassis dynamometer according to specified cycle test conditions.

[0026] On the one hand, the closed chamber is used to ensure that the temperature and humidity of the vehicle are controllable during the test process. At the same time, the non-exhaust particulate matter emitted by the vehicle can be retained in the closed chamber for collection and analysis.

[0027] Preferably, the temperature of the sealed chamber is generally controlled by blowing hot air / cold air into the sealed chamber to control the temperature change, and the air inlet is generally designed at the top of the sealed chamber. When the vehicle is running, the temperature and humidity in the sealed chamber need to be controlled within a certain range to avoid significant differences between the emission of non-exhaust particulate matter caused by overheating of the brake pads and tire wear during vehicle driving and the emission during actual driving.

[0028] Since non-exhaust particulate matter will adhere to the ground during the test, if the airflow with controlled temperature and humidity can be used to blow the particulate matter to the top of the closed chamber, it is very beneficial to the collection of the particulate matter. Therefore, this embodiment is provided with multiple blowers to blow the bottom and surrounding air of the new energy vehicle to the collection device at the top of the closed chamber at a specified wind speed. The specified wind speed here can be set based on experience. At the specified wind speed, the non-exhaust particulate matter in the closed chamber can be blown to the collection device.

[0029] Preferably, the plurality of blowers are arranged on the outside of the tire, the front of the vehicle and the rear of the vehicle respectively. Figure 1 , an air flow pipe of a hair dryer is introduced into the wall of the closed chamber corresponding to the direction of the four tires of the vehicle, the air flow is introduced into the closed chamber, and an air outlet is set on the outside of the vehicle tire to blow vertically toward the vehicle; counter-airflow is set on the outside of the wheel and in front and behind the vehicle, which can blow up the generated particulate matter and concentrate it on the top of the closed chamber, and can also play a role in cooling the braking system.

[0030] In addition, a hair dryer at the front of the vehicle can be used to dissipate heat, and the air flow from the hair dryer will flow to the rear of the vehicle. A hair dryer is also set at the rear of the vehicle, so that the air at the front and rear of the vehicle can blow against each other, and the air can be blown to the top of the closed chamber, which is conducive to the upward gathering of materials at the bottom of the vehicle and improves the collection efficiency.

[0031] It should be noted that the air intake of the multiple hair dryers is clean air of a specified temperature and a specified humidity. As the hair dryers blow, the air pressure in the closed room will increase. Therefore, in this embodiment, a first filter device is provided at the top of the closed room, and the non-exhaust particulate matter in the closed room is adsorbed by the first filter device, and the air is connected to the atmosphere at the same time to keep the air pressure in the closed room constant. In other words, the air in the closed room can enter the outside world through the first filter device, and at the same time, the first filter device can adsorb non-exhaust particulate matter to prevent the non-exhaust particulate matter from escaping into the atmosphere.

[0032] Since the first filter device absorbs part of the particles, the particles collected by the collection device will be reduced, affecting the test results. Based on this, the present embodiment provides two air branches and a micro fan to remix the particles absorbed by the first filter device into the closed chamber.

[0033] Continue to see Figure 1 The device has a first air branch at the top of the closed chamber, and a second air branch connected to both ends of the first air branch.

[0034] The first filter device is located in the first air branch, and the micro fan is located in the second air branch. A first valve is provided at the contact point between the first filter device and the first air branch, and a second valve is provided at the contact point between the first filter device and the second air branch.

[0035] The controller is set outside the closed room and can control the opening and closing of the first valve and the second valve wirelessly or wired. During the test, the controller controls the second valve to close and the first valve to open to disconnect the second air branch and connect to the atmosphere through the first filter device. At the same time, the first filter device absorbs non-exhaust particulate matter. After completing a test condition, multiple blowers can be controlled to close. The controller controls the second valve to open and the first valve to close to disconnect the first air branch, and the particulate matter in the first filter device is blown into the collection device through the micro fan. Figure 1 The hollow arrows in the figure indicate the direction of air flow. Since the air volume of the micro fan is relatively small, it will not affect the air pressure in the closed room.

[0036] In order to ensure that the particles adsorbed by the first filter device are successfully blown out, the first filter device is a filter element type filter, and the micro fan reversely introduces gas from the outlet end of the filter element, so that the airflow passes through the filter element in the reverse direction, blows up the particles originally adsorbed on the surface of the filter element, and carries them out of the filter with the reverse airflow. Figure 1 , the particles are blown out of the filter and directly enter the collection device.

[0037] Optionally, after a test condition is completed and the adsorbed particles are blown into the collection device, the collection device collects all the particles obtained in this test, and then the particles are analyzed.

[0038] Then the next working condition is tested, for example, the new energy vehicle runs at 60% power, and the power is gradually reduced on the basis of the previous 80% power. During the test, the controller collects the weight of the first filter device in real time through the weighing device. Optionally, the weighing device includes a pressure sensor, which is arranged below the first filter device. When the first filter device adsorbs more and more particulate matter, the weight of the first filter device detected by the pressure sensor is also increasing. Assuming that under the wind force of multiple hair dryers, the non-exhaust particulate matter generated by the vehicle will be evenly distributed above the closed chamber, then the weight change of the first filter device indicates the weight change of the adsorbed particulate matter, and also reflects the growth of the number of particulate matter in the closed chamber. The controller collects the weight sent by the weighing device and calculates the weight growth rate in real time. If the weight growth rate is higher than the set threshold (for example, 20%), it means that there are more particulate matter generated by the vehicle in the closed chamber, and a large amount of particulate matter is retained in the closed chamber and has not been blown into the collection device; in other words, the speed at which the vehicle generates particulate matter is greater than the speed at which it is blown into the collection device. Then, the controller (based on the specified wind speed) increases the wind speed of the hair dryer to speed up the flow of particulate matter to the collection device. The weight growth rate of the first filter device is calculated at intervals of a set time (e.g., 5s). If the weight growth rate decreases but is still higher than the set threshold, the wind speed of the hair dryer needs to be further increased. The weight growth rate of the first filter device is calculated at intervals of a set time. If the weight growth rate is lower than the set threshold, the current wind speed of the hair dryer is maintained.

[0039] Similarly, non-exhaust particulate matter under various test conditions can be obtained through the collection device. Under each test condition, the analysis device performs component analysis on the particulate matter collected by the collection device; the collected particulate matter is filtered and weighed by the second filtering device, and the non-exhaust particulate matter is retained to obtain the non-exhaust particulate matter emission data under each test condition.

[0040] Optional, see Figure 1 The device also includes a condensation device and a particle size analysis device; the condensation device condenses the gas collected in the collection device; the particle size analysis device separates and analyzes the background particle size of the collected particulate matter.

[0041] For details, see Figure 1, the collection device is connected to the condensation device, and the volatile substances such as VOCs are condensed and solidified through the condensation device, and only non-exhaust particulate matter remains after condensation. The component analysis device is used to perform quantitative and qualitative analysis on non-exhaust particulate matter. On the one hand, quantitative analysis can obtain the total amount of non-exhaust particulate matter emitted during vehicle driving. On the other hand, qualitative analysis can analyze the components of non-exhaust particulate matter through analytical instruments. Specifically, the analytical instruments can be selected as X-ray fluorescence spectrometer (XRF), inductively coupled plasma mass spectrometer (ICP-MS), inductively coupled plasma spectrometer (ICP-OES), etc., which can analyze the elemental composition of particulate matter and obtain the impact of its emissions on the environment and human health.

[0042] Optionally, before the test begins, first clean and remove impurities in the closed room. Then do a background test to detect the particle size of the remaining impurities in the closed room, select the corresponding filter, and separate the impurities above the background particle size. After separation, measure the components and particle size distribution of non-exhaust particulate matter through the component analysis device and the particle size analysis device.

[0043] The second filter device collects the generated non-exhaust particulate matter, specifically by filtering and weighing through a filter membrane, and finally analyzes to obtain non-exhaust particulate matter emission data, such as emission factors, types and weights of non-exhaust particulate matter, etc. Finally, the air is discharged.

[0044] Optionally, for hybrid vehicles, the device should also include an engine air intake pipeline extending to the engine air intake system to ensure engine air intake.

[0045] Optionally, the exhaust pipe of the new energy vehicle is connected to the outside of the closed chamber through a sealed pipeline to avoid collecting the exhaust gas.

[0046] The present invention provides a vehicle-level non-exhaust particulate matter testing device and method, and the whole vehicle is placed in a closed room to collect non-exhaust particulate matter. By arranging multiple hair dryers in the closed room, the bottom and surrounding air of the new energy vehicle are blown to the collection device at the top of the closed room, ensuring that all non-exhaust particulate matter can be fully collected. A first filter device is arranged on the top of the closed room, and the atmosphere is connected through the first filter device to keep the air pressure in the closed room constant during blowing, and due to the adsorption effect of the first filter device, the particles are prevented from leaking out. The new energy vehicle first drives according to the specified test conditions and changes the conditions to obtain emission data under each test condition. The weight growth rate of the first filter device indicates the growth rate of the particles in the closed room. If the growth is relatively fast, it means that a large amount of particles are retained in the closed room and have not been blown out. Then, the specified wind speed of the hair dryer is increased in order to blow out the particles in the closed room as soon as possible. The present invention guides the wind speed of the hair dryer through the weight change rate of the first filter device, which can improve the particle collection efficiency, find the optimal wind speed, and save the power loss of the hair dryer.

[0047] Example 2

[0048] This embodiment provides a method for testing non-exhaust particulate matter emissions from new energy vehicles, using the device provided in Example 1 for testing. The execution subject is a controller. Figure 2 , the method provided in this embodiment includes the following operations:

[0049] S110. The new energy vehicle is driven on a chassis dynamometer in a closed room according to specified test conditions; the specified test conditions include driving conditions at different power levels or different ambient temperatures.

[0050] S120, changing the working condition of the new energy vehicle, collecting the weight of the first filter device in real time through a weighing device during the test, and if the weight growth rate is higher than a set threshold, increasing the wind speed of the hair dryer until the weight growth rate is lower than the set threshold.

[0051] Optionally, the non-exhaust particulate emission data under various test conditions are counted and compared to obtain the test condition with the least amount of non-exhaust particulates. For example, after collecting the particulates under each test condition, the weight of various non-exhaust particulates is calculated, and the test condition with the smallest weight is selected.

[0052] Optionally, the controller can also control the wind speed of the hair dryer, and the opening and closing of the first valve and the second valve. For details, please refer to the description of Example 1, which will not be repeated here.

[0053] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0054] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A non-exhaust particulate matter emission test device for new energy vehicles, characterized in that: include: A chassis dynamometer, a closed chamber, a collection device for non-exhaust particulate matter, a first filtering device, a second filtering device, a weighing device, an analysis device for non-exhaust particulate matter, a plurality of blowers, and a controller; The new energy vehicle is driven on the chassis dynamometer in the closed room according to the specified test conditions; the specified test conditions include driving conditions at different power levels or different ambient temperatures; A plurality of blowers blow the bottom and surrounding air of the new energy vehicle toward the collecting device at the top of the closed chamber at a specified wind speed; A first filter device is disposed on the top of the closed chamber, and the first filter device absorbs non-exhaust particulate matter in the closed chamber and is connected to the atmosphere to keep the air pressure in the closed chamber constant; The test condition of the new energy vehicle is changed, and the controller collects the weight of the first filter device in real time through a weighing device during the test, and if the weight growth rate is higher than a set threshold, the wind speed of the hair dryer is increased until the weight growth rate is lower than the set threshold; Under each test condition, the particulate matter collected by the collecting device is analyzed for components by an analyzing device; the collected particulate matter is filtered and weighed by the second filtering device, non-exhaust particulate matter is retained, and non-exhaust particulate matter emission data under each test condition is obtained; The device also includes a first air branch at the top of the closed chamber, and a second air branch connected to both ends of the first air branch; The first filter device is located in the first air branch, and the micro fan is located in the second air branch; a first valve is provided at the contact between the first filter device and the first air branch, and a second valve is provided at the contact between the first filter device and the second air branch; During the test, the controller controls the second valve to close and the first valve to open, so as to disconnect the second air branch and connect to the atmosphere through the first filter device; After completing a test condition, the controller controls the second valve to open and the first valve to close, so as to disconnect the first air branch, and blow the particles in the first filter device into the collection device through the micro fan; The first filter device is a cartridge filter; The micro fan introduces gas in the reverse direction from the outlet end of the filter element, so that the airflow passes through the filter element in the reverse direction, blows up the particles originally adsorbed on the surface of the filter element, and carries them out of the filter with the reverse airflow.

2. The non-exhaust particulate matter emission test device for new energy vehicles according to claim 1, characterized in that: The weighing device comprises a pressure sensor, which is arranged below the first filtering device.

3. The non-exhaust particulate matter emission test device for new energy vehicles according to claim 1, characterized in that: Multiple blowers are arranged on the outside of the tire, the front and the rear of the vehicle.

4. The non-exhaust particulate matter emission test device for new energy vehicles according to claim 1, characterized in that: It also includes condensation equipment and particle size analysis equipment; The condensing device condenses the air collected by the collecting device, including substances such as VOCs generated by fuel evaporation when the hybrid vehicle engine is started; The particle size analysis device separates and analyzes the background particle size of the collected non-exhaust particulate matter.

5. A method for testing non-exhaust particulate matter emissions from new energy vehicles, characterized in that: Using the non-exhaust particulate matter emission test device for new energy vehicles according to any one of claims 1 to 4, the method comprises: The new energy vehicle is driven on the chassis dynamometer in the closed room according to the specified test conditions; the specified test conditions include driving conditions at different power levels or different ambient temperatures; The test conditions of the new energy vehicle are changed. During the test, the weight of the first filter device is collected in real time by a weighing device. If the weight growth rate is higher than a set threshold, the wind speed of the hair dryer is increased until the weight growth rate is lower than the set threshold.

6. The non-exhaust particulate matter emission test method for new energy vehicles according to claim 5, characterized in that: The non-exhaust particulate emission data under various test conditions are collected and compared to obtain the test condition with the least amount of non-exhaust particulates.

Images