A spoiler device for automotive wind tunnel testing

Abstract

This invention relates to a spoiler device for automotive wind tunnel testing. The spoiler device is installed in an automotive wind tunnel testing apparatus, which includes a wheel rotation unit and a moving belt unit. The wheel rotation unit includes a working belt and a wheel rotation unit chamber. The working belt is installed at one end of the wheel rotation unit chamber, and a gap exists between the working belt and the wheel rotation unit chamber. The spoiler device includes a spoiler installed within the gap between the working belt and the wheel rotation unit chamber. Compared with existing technologies, this invention has advantages such as reducing the influence of the aerodynamic characteristics of the wheel rotation unit on the surrounding flow field by installing a spoiler between the working belt and the wheel rotation unit chamber, thereby reducing aerodynamic drag errors during testing; the spoiler can be a strip plate, a brush, or an air pipe, adapting to the needs of different wheel rotation unit rotation speeds and shapes.

Description

Technical Field

[0001] This invention relates to automotive wind tunnel testing, and more particularly to a spoiler device for automotive wind tunnel testing. Background Technology

[0002] In automotive wind tunnel testing, a wheel-rotating unit and a moving belt system are used to simulate the flow field near the road surface on a real road. Figure 1 and Figure 2 As shown. The wheel rotation unit is an important component of the automotive wind tunnel road condition simulation system, such as... Figure 3 As shown, it is possible to approximate the flow field near the wheel.

[0003] The drag measurement error caused by the wheel-rotating unit in the wind tunnel needs to be corrected. Audi's full-size aeroacoustic wind tunnel uses a miniature moving belt to support the wheels, ensuring that the airflow around the wheels, especially the under-wheel jet, is similar to that of vehicles on actual roads. Wickern et al. studied the effect of a ground simulation system on aerodynamics through wind tunnel measurements. Experiments showed that the moving belt increases drag and decreases rear lift; while the miniature belt with the wheel-rotating unit reduces measured drag and increases front lift. For more accurate results, pad correction is necessary. The article provides a pad correction approach: adding a correction factor to the lift coefficient measurement to compensate for errors caused by differences in the belt and tire contact patch compared to actual conditions. The Stuttgart University Aeroacoustic Wind Tunnel (FKFS) performs a correction measurement before wind tunnel testing. This ensures that the test error is transmitted to the floor through the vehicle's mounting system, allowing the force measurement results to be directly expressed as lift or drag. To correct for the lift coefficient error caused by wheel motion, Yano et al. verified the results through CFD simulation and wind tunnel tests, measuring the pressure distribution of the wheel drive unit near the tire contact surface. They established a lift coefficient error model for the wheel rotation unit using multiple linear regression, which could calculate the lift coefficient error matrix by changing seven parameters and their combinations. Although the numerical fitting results did not agree well with the actual values, the experimental data showed good agreement with the CFD simulation results in their 6-vehicle, 10-condition wind tunnel test, revealing the influence of the wheel drive unit and its surface pressure distribution on the wind tunnel measurement data.

[0004] The error correction techniques mentioned above, such as those used by Wickern et al. and Yano et al., involve adding correction values ​​to aerodynamic measurement results in different ways to obtain corrected results. However, this method has poor versatility and cannot meet the testing correction requirements for different types of wheel rotation units under various wind speeds. The method proposed by Oliver et al., which involves performing correction tests before each formal test, is quite cumbersome. Both of these methods require frequent changes to correction values ​​or multiple sets of correction tests when conducting tests at multiple wind speeds, resulting in long testing times and high costs.

[0005] A search revealed that patent announcement number CN215205104U discloses a wheel spoiler assembly and an automobile, belonging to the field of vehicle technology. The assembly includes a track and a spoiler; the track is mounted on the chassis and located directly in front of the wheel; the spoiler is connected to a sliding component and a driving component; the sliding component is slidably connected to the track and can rotate relative to the track; the driving component is used to move the spoiler away from / approach the track so that the sliding component slides and rotates on the track; the spoiler has a first state where it slides to the front of the wheel to block airflow, and a second state where it slides to the side of the wheel to allow airflow towards the wheel. However, this prior art mainly focuses on spoiler design for automobiles and cannot reduce the aerodynamic drag error of the wheel rotation unit in automobile wind tunnel testing.

[0006] In summary, the technical problem that needs to be solved is how to design a device that can reduce the aerodynamic drag error of the wheel rotation unit in automotive wind tunnel testing and facilitate the testing process. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology, which involves a cumbersome automotive wind tunnel testing process, and to provide a spoiler device for automotive wind tunnel testing.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] According to one aspect of the present invention, a spoiler device for automotive wind tunnel testing is provided, the spoiler device being installed in an automotive wind tunnel testing apparatus, the automotive wind tunnel testing apparatus including a wheel rotation unit and a moving belt unit, the wheel rotation unit including a working belt and a wheel rotation unit chamber, the working belt being installed at one end of the wheel rotation unit chamber, and a gap being provided between the working belt and the wheel rotation unit chamber, the spoiler device including a spoiler being installed in the gap between the working belt and the wheel rotation unit chamber.

[0010] As a preferred technical solution, there are two gaps between the working belt and the wheel rotation unit chamber. The gap on the side where the working belt exits the wheel rotation unit chamber is the first gap, and the gap on the side where the working belt enters the wheel rotation unit chamber is the second gap. A spoiler is installed between the first gap and the second gap.

[0011] As a preferred technical solution, a baffle is installed between the first gap and the second gap.

[0012] As a preferred technical solution, the spoiler is long and strip-shaped with an L-shaped cross-section, including a first strip plate and a second strip plate that are perpendicular to each other. The first strip plate is attached to the edge of the wheel rotation unit chamber. One side of the second strip plate is connected to one side of the first strip plate, and the distance between the other side and the working belt is greater than 0 and less than 1 mm.

[0013] As a preferred technical solution, the spoiler is elongated and includes mutually perpendicular strip plates and brushes. The strip plates are attached to the edge of the wheel rotation unit chamber. One side of the brush is connected to one side of the first strip plate, and the other side is in contact with the working belt. The direction of the brush bristles is parallel to the direction of movement of the working belt.

[0014] As a preferred technical solution, the length of the spoiler is the same as the edge length of the wheel rotation unit chamber.

[0015] As a preferred technical solution, the spoiler includes an air inlet pipe and an air blowing pipe. One end of the air inlet pipe is connected to an air source, and the other end is connected to the air blowing pipe. The air blowing pipe is installed on the edge of the wheel rotating unit chamber and has an air blowing hole. The air blowing direction of the air blowing hole is parallel to the direction of movement of the working belt and opposite to the direction of movement of the working belt.

[0016] As a preferred technical solution, the length of the air blowing pipe is the same as the edge length of the wheel rotation unit chamber.

[0017] As a preferred technical solution, there are at least three air holes, which are evenly arranged on the air blowing pipe.

[0018] As a preferred technical solution, the air blowing pipe is a rigid air blowing pipe.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) This invention weakens the influence of the aerodynamic characteristics of the wheel rotation unit on the surrounding flow field by installing a spoiler between the working belt of the wheel rotation unit and the chamber of the rotation unit in the automotive wind tunnel, thereby reducing the aerodynamic drag error during the test. Since the spoiler can slow down the airflow carried by the belt movement, it restores the aerodynamic low-pressure area formed by this airflow in the wheel rotation unit area, so that the pressure before and after the wheel rotation unit is balanced, and the airflow deceleration effect is enhanced with the increase of wind speed. Therefore, this invention can automatically correct and compensate for the aerodynamic error of the wheel rotation unit according to the changes in wind speed and belt speed.

[0021] 2) The present invention installs a deflector in the gap on one or both sides of the working belt and the rotating unit chamber to adapt to the requirements of different wheel rotating unit rotation speeds; the deflector can be a strip plate, a brush or an air pipe to adapt to the requirements of different wheel rotating unit rotation speeds and shape structures.

[0022] 3) The length of the spoiler in this invention is equal to the edge length of the rotating unit chamber, ensuring that it can block the airflow carried by the belt at various positions during the belt movement, so as to balance the pressure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an automotive wind tunnel testing system.

[0024] Figure 2 Front view of the automotive wind tunnel testing system;

[0025] Figure 3 This is a schematic diagram of the wheel rotation unit structure;

[0026] Figure 4 A schematic diagram of the surface pressure distribution at the centerline of the working belt;

[0027] Figure 5 This is a schematic diagram of the first angle of the installation position of the spoiler on the wheel rotating unit in Embodiment 1 of the present invention;

[0028] Figure 6 This is a schematic diagram of the second angle of the installation position of the spoiler on the wheel rotating unit in Embodiment 1 of the present invention;

[0029] Figure 7 This is a schematic diagram of the spoiler structure in Embodiment 1 of the present invention;

[0030] Figure 8 This is a schematic diagram showing the installation position of the spoiler on the wheel rotating unit in Embodiment 2 of the present invention;

[0031] Figure 9 This is a schematic diagram showing the installation position of the spoiler on the wheel rotation unit in Embodiment 3 of the present invention;

[0032] Figure 10Comparison of ambient pressure around the working belt and wheel rotation unit with and without a spoiler installed;

[0033] Figure 11 These are wind tunnel test results for Embodiments 1, 2, and 3 of the present invention;

[0034] The numbers in the diagram are as follows:

[0035] 1. Wind tunnel floor; 2. Wheel rotation unit; 3. Moving belt unit; 4. Force balance; 5. Vehicle; 6. Wheel rotation unit cover plate; 7. Working belt; 8. Lifting lug; 9. Side opening; 10. Wheel rotation unit chamber; 11. Belt; 12. Motor; 13. Slide rail; 14. Base; 15. First internal roller; 16. Reinforcing rib; 17. Second internal roller; 18. Spoiler; 19. First gap; 20. Second gap; 21. First opening; 22. Second opening; 23. First strip plate; 24. Second strip plate; 25. Strip plate; 26. Brush; 27. Air blowing pipe; 28. Air inlet pipe. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] In automotive wind tunnel testing, the flow field near the road surface is simulated using a wheel rotation unit 2 and a moving belt system, such as... Figure 1 and Figure 2 As shown. Among them, the moving belt unit 3 simulates the movement of the road surface under the chassis of the test vehicle 5, and the wheel rotating unit 2 (WRU) simulates the movement of the road surface near the wheel and drives the wheel to rotate.

[0038] like Figure 3As shown, the wheel rotation unit 2 is an important component of the automotive wind tunnel road surface condition simulation system, capable of approximating the flow field near the wheel. The rotation unit chamber is mounted on the base 14 and the slide rail 13. The distance between the wheel rotation units 2 can be adjusted via the slide rail 13 to accommodate tests on vehicles 5 with different wheelbases. The base 14 is mounted on the force balance 4. By directly reading the balance's measurements, the lift and drag forces applied to the wheel rotation unit 2 are obtained. The wheel rotation unit cover plate 6 is mounted on the wind tunnel floor 1 via a stepped groove. It should be noted that the aerodynamic force measured by the force balance 4 is the force applied to the entire wheel rotation unit 2, i.e., the wheel rotation unit chamber 10 and the working belt 7 together constitute an internal force system. The force applied to this internal force system is the aerodynamic force measured by the force balance 4. The weight of the wheel rotation unit cover plate 6 and the forces applied to it are shielded and are not measured by the force balance 4. In addition, there are other accessories such as reinforcing ribs 16 to increase the rigidity of the wheel rotation unit chamber 10, lifting lugs 8 to facilitate the wheel rotation unit 2 to move in and out of the sinking chamber, and side openings 9 to balance the air pressure inside and outside the chamber, which together ensure the normal operation of the wheel rotation unit 2.

[0039] The belt 11 mechanism in the wheel rotation unit 2 is driven by the motor 12. The drive belt 11 rotates the first internal roller 15, causing the working belt 7 to reach the required speed. The ground opening exposes the translational portion of the upper surface of the working belt 7 to the wind tunnel test section. When the wheel is placed on the upper surface of the working belt 7, the friction between the moving working belt 7 and the wheel surface due to pressure drives the wheel to rotate. To avoid motion interference, gaps are unavoidable between the working belt 7 and the wind tunnel floor, and between the working belt 7 and the rotation unit chamber. When the working belt 7 moves, due to the boundary layer effect of the moving surface, the air in the boundary layer of the working belt 7 moves with the working belt 7. When this moving airflow passes through the first gap 19 and the second gap 20, the gaps act as Venturi channels, and the airflow carried by the working belt 7 accelerates, causing changes in the wall pressure of the gap portion. When the wheel rotation unit 2 is working, the working belt 7 always moves from front to back, which leads to uneven pressure in the airflow at the first gap 19 and the second gap 20. Figure 4 As shown. Since the movement of the working belt 7 belongs to the internal system of the balance, the internal force will not be measured by the balance. Therefore, the reason for the additional resistance is that the pressure is unevenly applied to the internal force system composed of the wheel rotation unit chamber 10 and the working belt 7, which in turn generates longitudinal pressure along the vehicle 5, which is measured by the force balance 4 and reflected macroscopically as the aerodynamic resistance error of the wheel rotation unit 2.

[0040] Example 1

[0041] like Figures 5-7As shown, this invention provides a spoiler device for automotive wind tunnel testing, including a wheel rotation unit 2, a moving belt unit 3, and a spoiler 18. The wheel rotation unit 2 includes a working belt 7 and a rotation unit chamber. The working belt 7 is installed at one end of the rotation unit chamber, and there is a gap between the working belt 7 and the rotation unit chamber. The spoiler 18 is installed in the gap between the working belt 7 and the rotation unit chamber. The function of the spoiler 18 is to impede the airflow carried by the movement of the working belt 7, thereby reducing the influence of the flow on the pressure field distribution.

[0042] There are two gaps between the working belt 7 and the rotating unit chamber. The gap on the side where the working belt 7 exits the rotating unit chamber is the first gap 19, and the gap on the side where the working belt 7 enters the rotating unit chamber is the second gap 20. A spoiler 18 is installed between the first gap 19, or between the second gap 20, or both the first gap 19 and the second gap 20 are equipped with a spoiler 18.

[0043] The spoiler 18 is long and narrow with an L-shaped cross-section. It includes a first strip plate 23 and a second strip plate 24 that are perpendicular to each other. The first strip plate 23 is attached to the edge of the rotating unit chamber. One side of the second strip plate 24 is connected to one side of the first strip plate 23, and the distance between the other side and the working belt 7 is greater than 0 and less than 1 mm, thus blocking the airflow. The length of the second strip plate 24 is the same as the length of the edge of the rotating unit chamber.

[0044] Example 2

[0045] like Figure 8 As shown, this invention provides a spoiler device for automotive wind tunnel testing, including a wheel rotation unit 2, a moving belt unit 3, and a spoiler 18. The wheel rotation unit 2 includes a working belt 7 and a rotation unit chamber. The working belt 7 is installed at one end of the rotation unit chamber, and there is a gap between the working belt 7 and the rotation unit chamber. The spoiler 18 is installed in the gap between the working belt 7 and the rotation unit chamber. The function of the spoiler 18 is to impede the airflow carried by the movement of the working belt 7, thereby reducing the influence of the flow on the pressure field distribution.

[0046] There are two gaps between the working belt 7 and the rotating unit chamber. The gap on the side where the working belt 7 exits the rotating unit chamber is the first gap 19, and the gap on the side where the working belt 7 enters the rotating unit chamber is the second gap 20. A spoiler 18 is installed between the first gap 19, or between the second gap 20, or both the first gap 19 and the second gap 20 are equipped with a spoiler 18.

[0047] The deflector 18 is elongated and includes mutually perpendicular strip plates 25 and brushes 26. The strip plates 25 are attached to the edge of the rotating unit chamber. One side of the brush 26 is connected to one side of the first strip plate 23, and the other side of the brush 26 is in contact with the working belt 7 to block the airflow. The brush 26 can be closely attached to the working belt 7 to achieve a better sealing effect. The direction of the brush bristles of the brush 26 is parallel to the direction of movement of the belt 11, and the length of the brush 26 is the same as the length of the edge of the rotating unit chamber.

[0048] Example 3

[0049] like Figure 9 As shown, this invention provides a spoiler device for automotive wind tunnel testing, including a wheel rotation unit 2, a moving belt unit 3, and a spoiler 18. The wheel rotation unit 2 includes a working belt 7 and a rotation unit chamber. The working belt 7 is installed at one end of the rotation unit chamber, and there is a gap between the working belt 7 and the rotation unit chamber. The spoiler 18 is installed in the gap between the working belt 7 and the rotation unit chamber. The function of the spoiler 18 is to impede the airflow carried by the movement of the working belt 7, thereby reducing the influence of the flow on the pressure field distribution.

[0050] There are two gaps between the working belt 7 and the rotating unit chamber. The gap on the side where the working belt 7 exits the rotating unit chamber is the first gap 19, and the gap on the side where the working belt 7 enters the rotating unit chamber is the second gap 20. A spoiler 18 is installed between the first gap 19, or between the second gap 20, or both the first gap 19 and the second gap 20 are equipped with a spoiler 18.

[0051] The spoiler 18 includes an air inlet pipe 28 and an air blowing pipe 27. One end of the air inlet pipe 28 is connected to a high-pressure air source, and the other end is connected to the air blowing pipe 27. The air blowing pipe 27 is installed at the edge of the rotating unit chamber and has air blowing holes. The air blowing direction of the air blowing holes is parallel to and opposite to the direction of movement of the belt 11, so that the gas is ejected in the opposite direction to the belt 11 at the position of the spoiler 18, thereby slowing down the airflow on the surface of the belt 11. The length of the air blowing pipe 27 is the same as the length of the edge of the rotating unit chamber. There are four air blowing holes, which are evenly arranged on the air blowing pipe 27. The air blowing pipe 27 is a rigid air blowing pipe to prevent uneven air blowing caused by deformation.

[0052] The influence of the wheel rotating unit 2 was analyzed by wind tunnel test section and flow field near the wheel rotating unit 2 using Star-CCM+ software. A simplified model of the wheel rotating unit 2 was used, with the inlet velocity set to 140 kph. The motion of the working belt 7 was simulated using the moving wall module in the software, and the surface moving velocity of the working belt 7 was also set to 140 kph. Two sets of simulations were set up for the conditions with and without the turbulence generator 18. The results are as follows. Figure 10 As shown. Analysis Figure 10It can be seen that the working belt 7, moving under the action of viscosity, drives the airflow, generating a significant pressure drop when passing through the first gap 19 and the second gap 20, causing turbulence at the first opening 21 and the second opening 22 on the ground of the wheel rotating unit 2. The airflow also generates a certain pressure drop when passing through the first gap 19 and the second gap 20, and the turbulence generated at the side opening of the wheel rotating unit 2 causes a certain pressure change. The pressure at the first gap 19 is greater than the pressure at the second gap 20, thus generating a force along the positive x-axis, which is reflected in the measurement results as a positive drag. After adding the spoiler 18, the pressure generated by the first gap 19 and the second gap 20 increases to a certain extent compared to when the spoiler 18 is not installed. The pressure increase at the second gap 20 is more significant than that at the first gap 19, which reduces the pressure difference of the working belt 7 along the x-direction, resulting in a decrease in drag.

[0053] Before adding spoiler 18, the drag analysis of the left front wheel rotating unit 2 yielded a drag result that converged to around 2.57 N. After adding spoiler 18, the drag result converged to around 1.85 N. The simulation results showed that the drag decreased by 27.7% compared with before adding spoiler 18, reflecting that the installation of spoiler 18 has a certain effect on reducing drag.

[0054] like Figure 11 As shown, after wind tunnel tests in Examples 1, 2, and 3, different types of spoilers 18 and single-sided or double-sided installation methods all showed a certain drag reduction effect. This invention proposes a spoiler device for automotive wind tunnel testing to study the mechanism of drag error generation in the wheel rotation unit. Adding spoilers 18 is expected to be applicable to various wind speeds and operating conditions, reducing drag error at its source. From the wind tunnel test results, the additional drag caused by the movement of the working belt 11 in the wheel rotation unit increases with the increase of the wind tunnel nozzle speed and the working belt 11 speed. Different types of spoilers all have a certain reduction effect on the additional drag caused by the belt movement in the wheel rotation unit. Adding brush spoilers at the slits on the front and rear walls of the wheel rotation unit cavity 17 has the best effect; as the wind tunnel nozzle speed and the working belt 11 speed increase, the drag reduction achieved by the spoilers also gradually increases.

[0055] This invention reduces the error in drag measurement results caused by the aerodynamic state of the wheel rotating unit 2 in automotive wind tunnels. Specifically, it addresses the drag error source by adding a spoiler 18 to the wheel rotating unit 2, weakening its aerodynamic characteristics. Specifically, the wheel rotating unit 2 generates a pressure difference between its front and rear sections during operation, leading to drag error. Compared to mainstream solutions such as the pad correction proposed by Wickern et al., which involve adding or subtracting correction values ​​based on function fitting or pre-experiments, the proposed solution reduces the aerodynamic drag error of the wheel rotating unit 2 to a certain extent without requiring correction tests or pre-experiments. Furthermore, under varying wind speeds and belt speeds in the test section, no manual adjustment of correction values ​​is needed. The spoiler slows down the airflow carried by the belt movement, restoring the aerodynamic low-pressure zone formed in the wheel rotating unit 2 region, thus balancing the pressure before and after the wheel rotating unit 2. The airflow slowing effect increases with wind speed. Therefore, the solution provided by this invention can automatically correct and compensate for the aerodynamic error of the wheel rotating unit 2 according to changes in wind speed and belt speed.

[0056] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A spoiler device for automotive wind tunnel testing, the spoiler device being installed in an automotive wind tunnel testing apparatus, the automotive wind tunnel testing apparatus comprising a wheel rotation unit (2) and a moving belt unit (3), the wheel rotation unit (2) comprising a working belt (7) and a wheel rotation unit chamber (10), the working belt (7) being installed at one end of the wheel rotation unit chamber (10), and a gap being present between the working belt (7) and the wheel rotation unit chamber (10), characterized in that, The spoiler device includes a spoiler (18) which is installed in the gap between the working belt (7) and the wheel rotation unit chamber (10); The spoiler (18) is long and has an L-shaped cross-section. It includes a first strip plate (23) and a second strip plate (24) that are perpendicular to each other. The first strip plate (23) is attached to the edge of the wheel rotation unit chamber (10). One side of the second strip plate (24) is connected to one side of the first strip plate (23), and the other side is at a distance greater than 0 and less than 1 mm from the working belt (7). Alternatively, the spoiler (18) is long and includes mutually perpendicular strip plates (25) and brushes (26). The strip plates (25) are attached to the edge of the wheel rotation unit chamber (10). One side of the brush (26) is connected to one side of the first strip plate (23), and the other side is in contact with the working belt (7). The direction of the brush bristles (26) is parallel to the direction of movement of the working belt (7). Alternatively, the spoiler (18) includes an air inlet pipe (28) and an air blowing pipe (27). One end of the air inlet pipe (28) is connected to an air source, and the other end is connected to the air blowing pipe (27). The air blowing pipe (27) is installed on the edge of the wheel rotating unit chamber (10) and has an air blowing hole. The air blowing direction of the air blowing hole is parallel to the movement direction of the working belt (7) and opposite to the movement direction of the working belt (7).

2. The spoiler device for automotive wind tunnel testing according to claim 1, characterized in that, There are two gaps between the working belt (7) and the wheel rotation unit chamber (10). The gap on the side where the working belt (7) exits from the wheel rotation unit chamber (10) is the first gap (19), and the gap on the side where the working belt (7) enters the wheel rotation unit chamber (10) is the second gap (20). A spoiler (18) is installed between the first gap (19) and the second gap (20).

3. A spoiler device for automotive wind tunnel testing according to claim 2, characterized in that, A spoiler (18) is installed between the first gap (19) and the second gap (20).

4. A spoiler device for automotive wind tunnel testing according to claim 1, characterized in that, When the spoiler (18) is long and has an L-shaped cross-section, including a first strip plate (23) and a second strip plate (24) that are perpendicular to each other, the first strip plate (23) is attached to the edge of the wheel rotation unit chamber (10), one side of the second strip plate (24) is connected to one side of the first strip plate (23), and the distance between the other side and the working belt (7) is greater than 0 and less than 1 mm; Alternatively, the spoiler (18) is long and includes mutually perpendicular strip plates (25) and brushes (26). The strip plates (25) are attached to the edge of the wheel rotation unit chamber (10). One side of the brush (26) is connected to one side of the first strip plate (23), and the other side is in contact with the working belt (7). When the direction of the brush bristles (26) is parallel to the direction of movement of the working belt (7); The length of the spoiler (18) is the same as the edge length of the wheel rotation unit chamber (10).

5. A spoiler device for automotive wind tunnel testing according to claim 1, characterized in that, When the spoiler (18) includes an air inlet pipe (28) and an air blowing pipe (27), one end of the air inlet pipe (28) is connected to an air source and the other end is connected to the air blowing pipe (27); the air blowing pipe (27) is installed on the edge of the wheel rotating unit chamber (10) and has an air blowing hole on it, and the air blowing direction of the air blowing hole is parallel to the movement direction of the working belt (7) and opposite to the movement direction of the working belt (7); The length of the air blowing pipe (27) is the same as the edge length of the wheel rotation unit chamber (10).

6. A spoiler device for automotive wind tunnel testing according to claim 1, characterized in that, When the spoiler (18) includes an air inlet pipe (28) and an air blowing pipe (27), one end of the air inlet pipe (28) is connected to an air source and the other end is connected to the air blowing pipe (27); the air blowing pipe (27) is installed on the edge of the wheel rotating unit chamber (10) and has an air blowing hole on it, and the air blowing direction of the air blowing hole is parallel to the movement direction of the working belt (7) and opposite to the movement direction of the working belt (7); The air blowing holes are at least three in number and are evenly arranged on the air blowing pipe (27).

7. A spoiler device for automotive wind tunnel testing according to claim 1, characterized in that, When the spoiler (18) includes an air inlet pipe (28) and an air blowing pipe (27), one end of the air inlet pipe (28) is connected to an air source and the other end is connected to the air blowing pipe (27); the air blowing pipe (27) is installed on the edge of the wheel rotating unit chamber (10) and has an air blowing hole on it, and the air blowing direction of the air blowing hole is parallel to the movement direction of the working belt (7) and opposite to the movement direction of the working belt (7); The air blowing pipe (27) is a rigid air blowing pipe (27).

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