Plasma control unit for reducing aerodynamic drag

Abstract

Plasma actuator, including: a substrate (18); a first electrode (14) on the substrate (18); a first dielectric layer (12) lying on the substrate (18) and covering the first electrode (14); a second electrode (10) on the first dielectric layer (12); a third electrode on the substrate (18) and covered by a second dielectric layer (12); and a fourth electrode on the second dielectric layer (12) and at a distance from the second electrode (10); characterized by the fact that that the first dielectric layer (12) and the second dielectric layer (12) are a single dielectric layer (12); and that both the first and third electrodes (14) and the second and fourth electrodes (10) are arranged in a mirror image to each other.

Description

TECHNICAL AREA OF THE PRESENT TECHNOLOGY

[0001] The present technology relates generally to transport vehicles such as automobiles and more specifically to a plasma actuator according to the preamble of claim 1 for reducing aerodynamic drag in automobiles. Such a plasma actuator is known essentially from WO 2008 / 058 011 A2.

[0002] Essentially comparable plasma actuators are also described in US 2010 / 0127624A1, US 2010 / 0072777A1 and US 2012 / 0152198A1. BACKGROUND OF THE PRESENT TECHNOLOGY

[0003] Fuel efficiency is one of the key selling points in today's automotive market. Consumers want cars with improved fuel efficiency so they can save money over the lifetime of the vehicle.

[0004] Fuel efficiency depends on several factors, such as engine design, body design, fuel quality, driving habits, and so on. Many factors, including comfort, style, and practicality, are considered when designing a car's body or exterior shape. The exterior shape influences the car's appearance and has a significant impact on aerodynamic drag, which in turn affects the vehicle's fuel efficiency.

[0005] Air resistance can be reduced, or flow separation at the vehicle's surface can be eliminated or controlled. Such flow control at the vehicle's rear requires additional mechanical equipment, which is installed alongside modifications to the body. Air resistance can also be reduced by changing the exterior shape. However, the exterior shape cannot be significantly altered because it changes the vehicle's aesthetics, which naturally also influences its popularity with customers.

[0006] The invention is therefore based on the objective of providing a realization that reduces air resistance and improves the fuel efficiency of automobiles without compromising aesthetics. BRIEF OVERVIEW OF THE TECHNOLOGY'S FORMS

[0007] This problem is solved with a plasma actuator having the features of claim 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings, which are included herein and form part of the specification, illustrate the technology at hand and, together with the description, further serve to explain the principles of the technology and enable a person skilled in the art to use this technology. Fig. Figure 1 is a schematic representation of a cross-sectional view of a conventional plasma actuator. Fig. Figure 2 is a perspective view of the schematic representation of the conventional plasma actuator. Fig. Figure 3 is an alternative schematic representation of a cross-sectional view of a conventional plasma actuator. Fig. Figure 4 is a representation of an automobile with plasma actuators. Fig. Figure 5 is another illustration showing the arrangement of the plasma actuators under the body of an automobile. Fig. Figure 6 is a third illustration of the arrangement of plasma actuators on an automobile. Fig. Figure 7 is a fourth illustration showing the arrangement of the plasma actuators on a side mirror. Fig. Figure 8 illustrates the use of a plasma actuator for boundary layer flow control. Fig. Figure 9 illustrates the application of a plasma actuator. Fig. Figure 10 shows a plasma actuator according to the invention. Fig. Figure 11 shows the contact force of the embodiment according to Fig. 10. Fig. Figure 12 is a representation of a flow control system. Fig. Figure 13 is another illustration of flow control. DETAILED DESCRIPTION OF TECHNOLOGY EXECUTIONS

[0009] Although the technology is described herein primarily in connection with automobiles, the disclosure is not limited to automobiles. The following descriptions can be applied to other moving objects such as airplanes, trucks, trailers, and trains, as just a few non-limiting examples.

[0010] The present disclosure describes a plasma actuator that reduces drag from the aerodynamic airflow. This reduction in aerodynamic drag is achieved by generating a plasma region that controls the flow separation edge on the surface of the vehicle body. The plasma actuator of the present technology is flush with any surface and interferes only minimally with the flow. Advantageously, in various embodiments, the plasma actuator has no moving parts and helps to improve fuel economy by reducing aerodynamic drag, improves vehicle stability control under harsher, unsteady flow environments, reduces wind noise around a vehicle, and reduces emissions and the CO2 footprint through improved fuel efficiency.Because of the lack of moving parts, the plasma actuator is easier to manufacture and is generally very robust and not prone to component failure during or between movements.

[0011] Plasma actuators add energy to boundary layers with low torque, thereby delaying the flow separation edge. An offset in the electrode arrangement allows the vehicle body to influence the air velocity tangentially to the surface. The force vector of the vehicle body can be controlled by the electrode arrangement and the dielectric material. The actuator is typically built in an asymmetrical configuration with an upper, exposed electrode and a lower, covered electrode separated by a dielectric material. Plasma actuators are compact, lightweight, and offer significant controllability by influencing local flow lines. Plasma actuators use high voltage (e.g., approximately 10 kV RMS) in the frequency range (e.g., around 20 kHz), a low current of 0.2 A, and have relatively low power consumption.The reaction time of the plasma actuator is approximately a few milliseconds, making it much faster than hydraulic, mechanical actuators (more than 100 seconds) currently used in high-performance vehicles.

[0012] Fig. Figure 1 is a schematic diagram of a conventional plasma actuator for reducing flow resistance – e.g., airflow. The plasma actuator has a first electrode 10, which is generally exposed to the airflow 16, a second electrode 14 embedded in a dielectric layer 12, and the plasma actuator is mounted on a substrate 18. The second electrode 14 can extend to the underside of the dielectric layer 12 and touch the substrate 18, as shown in Figure 1. Fig. 1 shown. The substrate 18 and all other parts of the plasma actuator can be flexible to be shaped according to the dimensions of the components of a target automobile, as referenced below.

[0013] In various embodiments, the leading edge of the first electrode 10 is located at a distance (laterally in the view of the Fig. 1) to a leading edge of the dielectric layer 12.

[0014] In various embodiments, a leading edge of the second electrode 14 is located below or adjacent to a trailing edge (in the direction of the airflow 16) of the first electrode 10 in one direction of the airflow 16 during operation. In some implementations, the electrodes are arranged such that they overlap at least partially (in a vertical direction of the view of the Fig. 1) and in others so that they do not overlap at all.

[0015] The first electrode 10 and the second electrode 14 are connected to a power source 20 via two separate terminals. While the power source 20 can be configured to deliver any of a variety of possible output powers, it can effectively deliver 10 kV in various embodiments. The power source 20 can be a DC or AC source. Plasma actuators connected to pulsed DC sources are superior in performance and generate a greater force on the vehicle body at significantly lower voltages compared to AC plasma actuators. The power consumption of pulsed DC plasma actuators with a 40-inch electrode is approximately 1 W, which is about 100 times lower than that of AC plasma actuators.When the air 16 flows over the plasma actuator, when the first electrode 10 and the second electrode 14 are energized by the power source 20, the airflow through the first electrode 10 and the second electrode 14 is ionized, resulting in the process described in . Fig. Figure 2 shows a plasma region 22 that extends from an edge of the first electrode 10. In one example, the thickness of the electrode, measured from top to bottom, is Fig. 1, approximately 0.1 mm, the thickness of the dielectric layer, measured from top to bottom in Fig. 1, varies from approximately 0.1 mm to approximately 6 mm depending on the voltage of the power source. The dielectric layer is configured with sufficient thickness in various embodiments to prevent a short circuit between the two electrodes 10, 14. The width of the electrode, measured from one side to the other in Fig. 1, is approximately 25 mm.

[0016] Fig. Figure 2 shows another embodiment of a conventional plasma actuator. Fig. 2 overlaps the first electrode 10 the second electrode 14. The two electrodes can be separated, as in Fig. 1 shown, or as in Fig. 2 overlap. The second electrode 14 is arranged below the dielectric layer 24 and within the substrate 18, and the plasma region 22 is formed in the direction of the airflow 16 by a trailing edge of the first electrode 10. In various embodiments, a leading upper edge of the first electrode 10 can align with a leading edge of the dielectric layer and / or the substrate, as shown in Fig. 2 shown.

[0017] Fig. Figure 3 shows another embodiment of a conventional plasma actuator. The first electrode 10 is arranged above a dielectric layer 24 and exposed to the airflow 16. The second electrode 14 is arranged at least partially within a substrate 18. The substrate 18 can be smaller than the dielectric layer 24. The first electrode 10 and the second electrode 14 are connected to the power source 20. Similar to the one already described for Fig. 1 and Fig. As described in Figure 2, when the air 16 flows over the first electrode 10 and the electrodes are charged, the air is ionized and forms a plasma region 22 after the trailing edge of the first electrode 10. The plasma introduces energy into the boundary layer of the airflow and thus delays the flow separation.

[0018] As shown, the novel plasma actuator very effectively reduces air resistance despite its relatively simple design. In various embodiments, the plasma actuator can be constructed as a thin strip of aluminum foil with a thickness similar to that of a strip of aluminum foil, featuring an adhesive layer for easy attachment to a vehicle body, or being bonded to one, and then connected to a power source. The thickness of the plasma actuator corresponds to the voltage of the power source—for example, the thickness of the plasma actuator is configured based on a known voltage, or the power source is selected or configured to supply current at a voltage corresponding to a predetermined thickness of the plasma actuator.Due to the relatively high voltage required to generate the plasma, the voltage level and the configuration of the plasma actuator should match to avoid damage from overvoltage to the plasma actuator and especially its very thin electrodes.

[0019] The plasma actuator can be positioned at various points on a vehicle body, preferably at or adjacent to (in front of or behind) various edges around the body where the boundary layer of the airflow tends to separate. Fig. Figure 4 shows a vehicle body with plasma actuators on different surfaces. As a first example, the plasma actuator can be arranged on the A-pillars (40) to reduce all vortex areas (reference numbers 82 in Fig. 8 as an example), which generally occur around the A-columns 40. The plasma actuator can be positioned, in particular, on or adjacent to each A-column, for example by placing it slightly in front of or behind the column. The plasma actuator can be configured to extend along all the different lengths of the column, including substantially along the entire length of the column, as in Fig. 4 shown. The plasma actuator is curved in various embodiments and / or shaped differently according to the dimensions of the column, and / or the plasma actuator consists of materials (some or all) to make the plasma actuator sufficiently flexible so that it can be shaped flush enough (e.g. bent with the bend of the column).

[0020] A plasma actuator according to the present technology can be used on all vehicle pillars, including one or more of the B-pillars and C-pillars.

[0021] A plasma actuator can also be arranged around the front fender 42 to control the airflow separation edge of the front tires and reduce the front tire wake. The plasma actuator can be positioned at or adjacent to the bumper and along its length. Again, the plasma actuator is curved and / or otherwise shaped according to the dimensions of the bumper in various embodiments, and / or the plasma actuator is made of materials (some or all) that make the plasma actuator sufficiently flexible to be formed flush (e.g., bent to match the curve of the bumper). In such cases, the plasma actuator can be positioned around the relevant vehicle component—e.g., around the bumper.

[0022] A plasma actuator can further be arranged on or adjacent to the rear fender 44 (e.g., a leading upper edge of the rear fender), and / or a plasma actuator can also be arranged on or adjacent to the trailing edge of the rear fender 46 to control the flow separation of the rear boundary layer flow and the resulting vortex vortex region. The plasma actuator can again be positioned on or adjacent to the rear fender or the trailing edge of the rear fender and along a length thereof. And again, the plasma actuator is curved and / or otherwise shaped in various embodiments according to the dimensions of the fender or edge, and / or the plasma actuator is made of materials (some or all) that make the plasma actuator sufficiently flexible to be formed flush enough with the rear fender or the trailing edge of the rear fender (e.g.,(with a bend in the rear fender or the trailing edge of the rear fender). Plasma actuators can be positioned around the relevant vehicle component in such cases – e.g., around the rear fender or the trailing edge of the rear fender.

[0023] The plasma actuator can be positioned in many other locations on the body of a car where airflow disturbances may occur. For example, the following illustrates... Fig. Five example locations on exposed vehicle surface(s) under the chassis of an automobile where the plasma actuator can be positioned. The plasma actuator can be positioned under the front spoiler 50 around the underbody panels 52, 54, 56. By positioning the plasma actuator at these locations under the chassis, airflow disturbance can be reduced and consequently, drag can be lowered.

[0024] Fig. Figure 6 shows locations on the rear of an automobile where plasma actuators can be positioned. The actuators around the trailing edge of the rear fender 64 can improve the vehicle's aerodynamic stability in crosswinds or unsteady flow environments. The plasma actuator 60 positioned at the edge of the roof can also be used to trigger the flow separation edge 66 of the airflow around the body, thereby reducing lift and improving stability in crosswinds. By arranging two opposing plasma actuators ( Fig. 10) A downward force 116 can be generated around the rear edge 62 of the trunk or trunk lid near the rear of the vehicle. The downward force at the rear end improves vehicle stability in strong crosswinds. The airflow 112, which passes over the two opposing plasma actuators 62 (also Fig. 10) flows at the edge of the trunk lid, interacting with the upward flows 114, 110. The interaction between the flows 112 and 114 generates downward forces 116, 103 as shown in Fig. 10 and Fig. 11 shown.

[0025] A plasma actuator of the present technology can have different designs that allow for better control of the induced airflow. Fig. Figure 10 shows a plasma actuator according to the invention consisting of a combination of two plasma actuators 102 and 104. Each of the plasma actuators 102 and 104 has a similar structure to that shown in Figure 10. Fig. 1 described on. In one embodiment, one or both plasma actuators are as described in Fig. Figure 2 shows that the plasma actuators 102 and 104 are opposite each other and mirror each other. The plasma actuators 102 and 104 can be arranged on a common substrate 18, and each plasma actuator consists of an exposed electrode 10 above a dielectric layer 12 with another electrode 14 embedded in the dielectric layer 12, as well as a power source 20 connected to both electrodes 10 and 14. Each plasma actuator modifies the incoming airflow above the plasma actuator. Since two plasma actuators 102, 104 are arranged opposite each other, the induced flows 106, 108 are opposite to each other, thus generating an upward flow 110. This embodiment of the plasma actuator, when placed on the edge of a car's trunk lid, generates a downward force 103 due to the upward flow 110. Although in Fig. Figure 10 shows two separate dielectric layers; according to the invention, it is provided that they are replaced by a single dielectric layer over both plasma actuators 104. Furthermore, the two plasma actuators 102, 104 can be powered by a single current source.

[0026] The plasma actuator of Fig. 1 can be as in Fig. Figure 7 shows the plasma actuator being arranged around the front pillar (A-pillar). The plasma actuator 70 reduces the vortex 78 that forms at or adjacent to the windshield 74 and the front windscreen 76, thereby reducing the overall drag of the vehicle. The plasma actuator can also be arranged around the exterior mirror 72 to reduce vortices around the exterior mirror and thus reduce the overall drag of the vehicle.

[0027] The plasma actuator can also be used to control boundary layer flows. Fig. Figure 8 shows the flowing air 80 in a direction generally parallel to the lengths of electrodes 10 and 14. As the air 80 flows over the plasma actuator, the plasma actuator induces an airflow 16 from the exposed electrode 10, forming a plasma region 22. The induced airflow 16 forms the vortex 82 around the plasma region 22. The intensity of the induced airflow 16 and the vortex 82 depends on the size or strength of the plasma region 22, which in turn depends on the voltage intensity of the power source. The plasma region 22 also depends on the distance between the two electrodes. The boundary layer of a flow can be controlled by positioning the plasma actuator relative to the airflow. Fig. Figure 12 shows the positioning of the plasma actuator 122 with an induced airflow 126 flowing against the air 124 flowing over the plasma actuator. When the air 124 flows against the induced air 126, a flow separation edge is generated in the area 128. Fig. Figure 13 shows the positioning of the plasma actuator 132 such that the induced air 136 flows in the same direction as the incoming airflow 134.

[0028] The plasma actuator changes the properties of a flowing fluid over a surface, and the plasma actuator of the present technology can be used for many different applications. Fig.Figure 9 shows the arrangement of a plasma actuator 94 on a wing 90 of an aircraft. When the plasma actuator 94 is activated, it induces an incoming airflow 16 that flows closer to the surface of the wing 90 and prevents the premature or premature appearance of the flow separation edge 92. The plasma actuator can also be arranged on the edge of a submarine propeller and modify the submarine's acoustic properties.

Claims

[1] Plasma actuator comprising: a substrate (18); a first electrode (14) on the substrate (18); a first dielectric layer (12) lying on the substrate (18) and covering the first electrode (14); a second electrode (10) on the first dielectric layer (12); a third electrode on the substrate (18) and covered by a second dielectric layer (12); and a fourth electrode on the second dielectric layer (12) and spaced from the second electrode (10); characterized by , that the first dielectric layer (12) and the second dielectric layer (12) are a single dielectric layer (12); and that both the first and third electrodes (14) and the second and fourth electrodes (10) are arranged mirror-inverted to one another. [2] Automobile, comprising: a surface; and at least one plasma actuator according to claim 1 on the surface of the automobile. [3] The automobile of claim 2, further comprising a trunk lid, wherein the surface is a surface of the trunk lid and the plasma actuator is disposed at an edge of the trunk lid. [4] The automobile of claim 2, further comprising a chassis, wherein the surface is below the chassis. [5] The automobile of claim 2, further comprising a side mirror (72), wherein the surface is part of the side mirror (72) and the plasma actuator is disposed around a portion of or all of the side mirror (72).

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