Automobile tail weak shock wave drag reduction device and drag reduction method

Abstract

The invention discloses an automobile tail weak shock wave resistance reduction device and a resistance reduction method, and belongs to the technical field of automobile aerodynamics resistance reduction. A pneumatic structure is arranged at the tail of the automobile, high-speed airflow is suddenly blocked and compressed, local controllable weak shock waves are formed, a high-pressure area generated by the weak shock waves is used for filling an automobile tail vacuum area, automobile tail static pressure is improved, the pressure difference between an automobile head and an automobile tail is reduced, and therefore the pressure difference resistance of the whole automobile is reduced. The pneumatic structure is preferably an L-shaped structure, can also adopt other structural forms capable of generating weak shock waves, and can be mounted on the left side, the right side or the two sides of the tail of the vehicle. The device is simple in structure, free of energy consumption, low in cost and remarkable in resistance reduction effect, the protection range covers all schemes for achieving resistance reduction by filling vacuum through weak shock waves, and the device is not limited by the specific appearance and the installation direction.

Description

Technical Field

[0001] This invention relates to the field of automotive aerodynamic drag reduction technology, specifically to a drag reduction device and method that reduces pressure drag by generating a locally controllable weak shock wave at the rear of the vehicle to fill the vacuum area at the rear. Background Technology

[0002] During vehicle operation, a low-pressure vacuum zone forms at the rear of the vehicle, generating significant pressure drag, which is one of the main sources of vehicle drag. Traditional rear drag reduction structures primarily focus on guiding airflow and delaying airflow separation, failing to address the root cause of the vacuum zone and thus offering limited drag reduction. Existing automotive aerodynamic designs generally consider shock waves as a detrimental factor increasing drag and deliberately avoid their generation. This invention breaks with conventional industry understanding by actively utilizing locally controllable weak shock waves to fill the rear vacuum zone, reducing pressure drag at its source, demonstrating significant novelty and inventiveness. Summary of the Invention

[0003] 1. Technical Solution: A drag reduction device for a weak shock wave at the rear of a vehicle, characterized by: an aerodynamic structure installed at the rear of the vehicle, causing a sudden obstruction and local compression of high-speed airflow, forming a locally controllable weak shock wave at the rear; the high-pressure area generated by the weak shock wave fills the vacuum area at the rear of the vehicle, increasing the static pressure on the rear surface and reducing the pressure difference between the front and rear of the vehicle, thereby reducing the overall vehicle pressure drag and achieving net drag reduction. The aerodynamic structure can be installed on the left, right, or both sides of the rear of the vehicle; the installation orientation does not affect its drag reduction working principle. The aerodynamic structure is preferably an L-shaped (seven-shaped) structure, but other structural forms that can suddenly obstruct the airflow and generate a weak shock wave are also possible. The vertical section of the L-shaped structure is used to obstruct the airflow and form a stable weak shock wave, while the horizontal section is used to adhere to the vehicle body and guide the airflow, resulting in a better drag reduction effect. As the preferred implementation, a 3-10 mm airflow channel is reserved between the bottom of the vertical section of the L-shaped aerodynamic structure and the vehicle body surface, allowing airflow to pass under the vertical section and directly impact its windward surface, forming a local weak shock wave; the high-pressure airflow, guided by the vertical section, directly fills the vacuum area at the rear of the vehicle, significantly improving drag reduction efficiency. The aerodynamic structure is preferably located at the rear of the vehicle, close to the vacuum area. 2. Structural dimensions: The dimensions of the L-shaped aerodynamic structure are as follows: the height of the vertical section itself is 6-20 mm (preferably 10 mm); the height of the airflow channel between the bottom of the vertical section and the vehicle body surface is 3-10 mm (preferably 5 mm); the thickness in the front-rear direction is 1-4 mm (preferably 2 mm), with a steep front edge, without rounded transitions or chamfered edges; the horizontal section extends forward along the vehicle body for 10-50 mm (preferably 20-30 mm); the lateral length is 50%-90% of the total width of the rear of the vehicle. 3. Beneficial effects: Simple structure, passive operation, no additional energy consumption, low cost, and easy installation; fills the vacuum area at the rear of the vehicle from the source, effectively reducing pressure difference drag, with a direct drag reduction effect; the L-shaped structure with airflow channels brings the high-pressure area closer to the vacuum area, resulting in higher airflow filling efficiency; suitable for various passenger vehicle models such as sedans, SUVs, and MPVs, without requiring vehicle body modification, and can be flexibly installed on the left, right, or both sides of the rear, with strong versatility; the protection range is based on the core innovative principle and is not limited by specific shape or installation orientation, covering all similar structures that use shock waves to fill the vacuum to achieve drag reduction. Figure 1 This is a schematic cross-sectional view of the preferred L-shaped structure of the present invention; Figure 2 This diagram illustrates the installation location and airflow direction of the L-shaped structure at the rear of the vehicle. Labeling information: 1—Vehicle surface; 2—L-shaped aerodynamic structure; 3—Vertical section; 4—Horizontal section.

Claims

1. A drag reduction device for the rear of a vehicle, characterized in that: An aerodynamic structure is installed at the rear of the vehicle. The aerodynamic structure has a steep frontal surface that suddenly obstructs and compresses the airflow to form a locally controllable weak shock wave at the rear. The high-pressure area generated by the weak shock wave fills the vacuum area at the rear of the vehicle, increasing the static pressure at the rear and reducing the vehicle's pressure drag. The aerodynamic structure can be installed on the left, right, or both sides of the rear of the vehicle.

2. The vehicle rear drag reduction device according to claim 1, characterized in that: The aerodynamic structure is an L-shaped (seven-shaped) structure.

3. The vehicle rear drag reduction device according to claim 2, characterized in that: A 3-10 mm airflow channel is reserved between the bottom of the vertical section of the L-shaped aerodynamic structure and the vehicle surface, allowing airflow to pass through and impact the windward side of the vertical section.

4. The vehicle rear drag reduction device according to claim 1, characterized in that: The aerodynamic structure is located at the rear of the vehicle, near the vacuum zone.

5. The vehicle rear drag reduction device according to claim 2, characterized in that: The vertical section of the L-shaped aerodynamic structure has a height of 6–20 mm, a thickness of 1–4 mm in the front-to-back direction, and a lateral length of 50%–90% of the total width of the rear of the vehicle.

6. The vehicle rear drag reduction device according to claim 1, characterized in that: The aerodynamic structure has a steep leading edge with no rounded transition or chamfered edge.

7. A method for reducing drag at the rear of a vehicle, characterized in that: By suddenly obstructing and compressing the airflow at the rear of the vehicle, a locally controllable weak shock wave is formed. The high pressure of the shock wave fills the vacuum area at the rear of the vehicle, increasing the static pressure at the rear and thus reducing the vehicle's pressure drag. This method is applicable to the left, right, or both sides of the rear of the vehicle, and is applied to one or both sides. The weak shock wave is an oblique shock wave, and the pressure ratio before and after the shock wave is controlled between 1.1 and 1.5 to avoid excessive total pressure loss.

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