Vehicles with a bottom structure for reducing aerodynamic drag

Abstract

A vehicle includes a bottom structure disposed at the rear bottom side of the vehicle, wherein the vehicle is an automobile used on a public road, wherein the bottom structure includes at least a vortex portion that slopes upward when viewed in a direction from the front end to the rear end of the vehicle, wherein the vortex portion substantially covers the width of the vehicle, and is adapted to generate a bottom air vortex below the vortex portion when the vehicle moves forward.

Description

Technical Field

[0001] This invention relates to the technical field of vehicles, such as automobiles used on public roads. In particular, this invention relates to aerodynamics at the rear end of a vehicle and to the underbody structure for a vehicle.

[0002] The project that gave rise to this application has been funded by the EU Horizon 2020 research and innovation program, pursuant to Grant Agreement No. 848620. Background Technology

[0003] Given the impacts of climate change and greenhouse gases, there is a desire to reduce fuel consumption in vehicles. This can be achieved, for example, by reducing the vehicle's aerodynamic drag (e.g., by reducing the drag coefficient). Completely eliminating fossil fuels could be accomplished by providing electric vehicles with electric motors instead of internal combustion engines. One area of ​​current improvement for electric vehicles is the driving range before the need to recharge the battery. Driving range can also be improved by reducing the vehicle's aerodynamic drag.

[0004] It is well known that vehicles should have a teardrop shape to minimize aerodynamic drag. However, in practice, this is often not entirely possible due to practical problems and design constraints. For example, cars typically have a rear trunk that must provide sufficient space. Another example of practical constraints is the departure angle. The departure angle must be large enough to ensure sufficient ground clearance for the vehicle to travel on uneven surfaces such as hills, speed bumps, or holes in the ground. Summary of the Invention

[0005] The object of the present invention is to provide a vehicle with improved aerodynamic performance (e.g., reduced aerodynamic drag and / or drag coefficient), or at least to provide an alternative to a known solution.

[0006] One or more objects of the present invention are achieved by a vehicle comprising a bottom structure disposed at the rear bottom of the vehicle, wherein optionally, the vehicle is, for example, a car used on public roads. According to the present invention, the bottom structure includes:

[0007] It includes at least a vortex portion that slopes upwards when viewed from the front to the rear of the vehicle, wherein the vortex portion optionally substantially covers the width of the vehicle.

[0008] • Suitable for generating bottom air vortexes below the vortex section when the vehicle is moving forward.

[0009] Therefore, the present invention relates to a vehicle. The vehicle may be, for example, an automobile used on public roads. The vehicle may be, for example, a passenger vehicle suitable for transporting multiple people, such as two, four, five, seven, or more. The vehicle may be a cargo vehicle suitable for transporting goods. For example, the vehicle may be an autonomous vehicle, such as an automated guided vehicle or Automated Guided Vehicle adapted to terrain such as warehouses or outdoor environments. The vehicle includes an internal combustion engine for providing propulsion. The vehicle may include an electric motor for providing propulsion. The vehicle may include one or more solar panels for charging the battery and / or for providing energy to the electric motor. Typically, the vehicle moves on the ground.

[0010] In the context of this document, terms such as “front,” “rear,” “bottom,” “upper,” “top,” and “tilt” are defined according to the situation when the vehicle is moving forward on a horizontal surface and / or when the vehicle is horizontally arranged.

[0011] The vehicle includes a bottom structure. The bottom structure is located at the rear bottom of the vehicle. When the vehicle includes front and rear wheels, the bottom structure is positioned, for example, behind the rear wheels. The bottom structure may be positioned, for example, between the rear wheels and the rear end of the vehicle. Optionally, the vortex portion extends to the rear end of the vehicle. The bottom structure is part of the vehicle's bottom, meaning that when the vehicle is positioned on a level surface, no vehicle components are positioned between the bottom structure and the ground. The bottom structure may be, for example, part of the vehicle's floor panel.

[0012] The underbody structure includes at least a vortex portion. When viewed along a first direction from the front to the rear of the vehicle, the vortex portion slopes upwards. That is, the front end of the vortex portion is positioned below the rear end. Between the front and rear ends, the vortex portion may have a variable angle of inclination, for example, the vortex portion may be curved. The vortex portion may optionally substantially cover the width of the vehicle. The vortex portion ensures that the underbody structure of the vehicle is higher when viewed closer to the rear end of the vehicle. This can be particularly advantageous when the vehicle needs to maneuver on non-flat surfaces such as hillsides, holes or obstacles in the ground, or traffic barriers. For example, when the vehicle includes rear wheels, there is a risk that the underbody surface positioned between the rear wheels and the rear end of the vehicle will contact the ground on a non-flat surface. Such contact may result in damage and / or an unpleasant user experience. Because the vortex portion of the underbody structure slopes upwards, the risk of contact with the ground is reduced.

[0013] The underbody structure is adapted to generate an under-air vortex below the vortex section when the vehicle moves forward. As the vehicle moves forward, the air around the vehicle moves. When viewed relative to the vehicle, the air flows from the front to the rear of the vehicle. An under-air vortex is generated, for example, by the effect of the shape of the underbody structure on the flowing air. By generating an under-air vortex, the aerodynamic drag of the vehicle is reduced. This can be understood as follows: Typically, the slant of the vortex section deviates from the theoretically desired teardrop shape. By generating an under-air vortex below the vortex section, the under-airflow is prevented from flowing along the vortex section. The under-airflow includes the surrounding air that flows beneath the vehicle towards the rear end as the vehicle moves forward. The under-airflow separates from the underbody structure before the rear end of the vehicle and flows below the under-air vortex. The under-airflow flows along a contour similar to a teardrop shape rather than the physical shape of the vehicle. This provides a favorable aerodynamic profile. Simultaneously, the favorable physical profile, with its slanted vortex section, allows the vehicle to maneuver on non-flat surfaces.

[0014] The bottom air vortex can be adapted to propagate in a second direction substantially perpendicular to the first direction. For example, the bottom air vortex is adapted to propagate in the second direction toward the left and / or right side of the vehicle. For example, the air vortex is adapted to propagate tangentially to the vehicle. It has been found that this is advantageous for the remaining airflow below and behind the vehicle. Note that this is different from a so-called "vortex generator," which is known, for example, to be arranged on the roof of a car or the wing of an aircraft. The vortex generator produces air vortices that propagate in the direction of travel or flight of the vehicle, i.e., in the first direction.

[0015] In this embodiment, when viewed from the left side of the vehicle, the bottom air vortex is oriented counterclockwise. When viewed from the right side of the vehicle, the bottom air vortex is oriented clockwise. At the bottom of the bottom air vortex, air flows toward the rear end of the vehicle, thereby improving the rearward flow of surrounding air in the bottom airflow. At the top of the bottom air vortex, air flows toward the front end of the vehicle and can provide advantageous friction on the surface of the vortex portion, for example, in the direction of travel.

[0016] In this embodiment, the departure line is defined as a virtual line extending from the ground plane toward the rear end of the vehicle and tangential to the rear wheels. An underbody structure is arranged above the departure line, and an underbody airflow extends beyond the departure line. At least a portion of the underbody airflow is below the departure line. The departure line extends through the underbody airflow. Thus, the underbody airflow flows along an aerodynamic profile that extends beyond the departure line. In this embodiment, the physical profile of the underbody structure is ensured to facilitate vehicle maneuverability on non-flat surfaces, while the underbody airflow flows via a favorable aerodynamic profile. For example, the departure line could be a virtual line between the ground and the rear underside of the vehicle.

[0017] In an embodiment, the departure angle is defined as the angle between the horizontal plane and the departure line, wherein the departure angle is at least 10 degrees. For example, the departure angle can be at least 15 degrees, 18 degrees, or 20 degrees. The departure angle is, for example, suitable for vehicles used on public roads. The departure angle can be further determined based on the intended application of the vehicle. For vehicles used for off-road applications, the departure angle can be, for example, larger than the departure angle used for vehicles primarily used on public roads.

[0018] In an embodiment, the underbody structure further includes an air guide portion, which is positioned prior to the vortex portion when viewed in a direction from the front end to the rear end of the vehicle. The air guide portion abuts the vortex portion at a transition line. The air guide portion may, for example, be positioned between the rear wheel of the vehicle and the vortex portion. The air guide portion may be adapted to guide underbody airflow toward the vortex portion as the vehicle moves forward. The transition line may be adapted to separate the underbody airflow from the underbody structure. Optionally, the air guide portion may include a guiding element for guiding the underbody airflow according to a predetermined flow profile. Optionally, the air guide portion may include a low-friction material and / or surface roughness forming between the underbody structure and the underbody airflow flowing above the air guide portion.

[0019] In this embodiment, the transition angle between the air guide portion and the vortex portion is at least 45 degrees at the transition line. For example, the transition angle can be at least 50 degrees, 60 degrees, or 75 degrees. The inventors have found that having a relatively large transition angle helps to generate bottom air vortices below the vortex portion and to separate the bottom airflow from the bottom structure.

[0020] In embodiments, the air guide portion and the vortex portion are adapted to guide bottom airflow toward the transition line at an approach angle of 60-120 degrees, for example 75-105 degrees, or substantially perpendicular to the transition line, as the vehicle moves forward. For example, the air guide portion may be shaped accordingly and / or have guiding elements. For example, the vortex portion may be shaped accordingly, for example, with its boundary corresponding to the transition line. The inventors have found that, generally, the closer the approach angle is to 90 degrees, the larger the resulting bottom air vortex. Optionally, when viewed in the width direction of the vehicle, the approach angle may be closer to 90 degrees at the center of the transition line than on the left and / or right portions of the transition line. This can allow the generation of a bottom air vortex that is larger below the center of the vortex portion than below the left and / or right portions. The left and / or right portions may be the outer ends of the vortex portion when viewed in the width direction of the vehicle.

[0021] In this embodiment, the vortex portion is arranged at an average tilt angle, and the air guide portion is arranged at an average air guide portion tilt angle, wherein the average tilt angle is greater than the average air guide portion tilt angle. The average air guide portion tilt angle may, for example, be greater than zero degrees. The air guide portion may, for example, be arranged to tilt upwards when viewed from the front to the rear of the vehicle. An average tilt angle greater than the average air guide portion tilt angle means that the vortex portion is more tilted than the air guide portion. This may be advantageous for generating under-air vortices and for separating under-airflow.

[0022] In one embodiment, the vortex portion has a concave shape. In another embodiment, the vortex portion has a parabolic shape with a hyperbolic shape. The inventors have found that these shapes help to generate a bottom air vortex below the vortex portion. Furthermore, when viewed from the side, the bottom air vortex can be substantially circular, and in these embodiments, the shape of the vortex portion allows the bottom air vortex to at least partially fit into the vortex portion. This reduces friction between the bottom air vortex and the vortex portion.

[0023] In this embodiment, the bottom air vortex is larger below the center of the vortex portion than below the left and / or right portions of the vortex portion. When viewed in the width direction of the vehicle, the left and / or right portions may, for example, be the outer ends of the vortex portion. For example, making the bottom air vortex smaller near the side of the vehicle can reduce the influence of the bottom air vortex on the surrounding air flowing along the side of the vehicle, which may be advantageous for the overall aerodynamic profile and aerodynamic drag.

[0024] In embodiments, the underbody structure and / or vehicle further includes a diffuser arranged in front of the vortex portion when viewed from the front to the rear of the vehicle. For example, in embodiments where the underbody structure also includes an air guide portion, the air guide portion may include a diffuser. The diffuser may be adapted to slow down and / or expand the underbody airflow, thereby improving the integration of the airflow with other air, such as behind the rear of the vehicle. The diffuser is preferably arranged adjacent to the vortex portion. This allows the diffuser to influence the underbody airflow before it separates from the underbody structure.

[0025] In an embodiment, the vehicle is adapted to generate at least one rear air vortex behind the rear end of the vehicle as the vehicle moves forward. Optionally, the vehicle is adapted to generate an upper rear vortex and a lower rear vortex, the upper rear vortex being oriented clockwise, for example, when viewed from the left side of the vehicle, and the lower rear vortex being oriented counterclockwise, for example, when viewed from the left side of the vehicle. For example, the shape of the rear end of the vehicle may be adapted to generate at least one rear air vortex. At least one rear air vortex may facilitate the guidance of bottom airflow and optionally guide upper airflow behind the rear end of the vehicle.

[0026] In this embodiment, the vehicle is an automobile that includes an electric motor as a propulsion source. For example, the vehicle may include a battery for supplying power to the electric motor. By providing the vehicle with the underbody structure of the present invention, the driving range required before the battery can be recharged can be increased. Furthermore, using an electric motor instead of an internal combustion engine eliminates the need for an exhaust system at the rear end of the vehicle. From an aerodynamic point of view, an exhaust system may additionally adversely affect the design of the underbody structure and / or vortex section. Moreover, exhaust gases and / or heat emitted via said exhaust system may adversely affect how the surrounding air flows at the rear end of the vehicle.

[0027] In embodiments, the vehicle includes solar panels on the roof and / or upper rear side of the vehicle. For example, the solar panels may be adapted to supply energy to an electric motor or a battery for the electric motor. When a vehicle includes solar panels, it may be desirable to have a relatively large surface area on which the solar panels can be arranged so that the solar energy captured by the solar panels can be optimized. This may result in a relatively long vehicle with a relatively long rear length. A long rear length can cause problems when the vehicle is maneuvering on non-flat surfaces. Simultaneously, it may be desirable to minimize aerodynamic friction as much as possible to increase driving range. The bottom structure according to the invention can also be advantageous.

[0028] The present invention further relates to a bottom structure for a vehicle, adapted to be disposed at the rear bottom of the vehicle to form a rear bottom of the vehicle. The bottom structure includes at least a vortex portion that, when the bottom structure is disposed on the vehicle, slopes upward when viewed from the front to the rear of the vehicle. Optionally, the vortex portion substantially covers the width of the vehicle. The bottom structure is adapted to generate a bottom air vortex below the vortex portion as the vehicle moves forward. It will be understood that the bottom structure may optionally include any of the features or embodiments described herein.

[0029] Although described herein with reference to the underside structure of a vehicle, it will be understood that the invention can also be applied to other applications. Therefore, the present invention relates to a vehicle including an external structure disposed on the outer side of the vehicle. The vehicle may be, for example, an automobile used on public roads. The external structure includes at least a vortex portion, wherein the vortex portion has a concave, parabolic, or hyperbolic shape. The external structure further includes an air guide portion, wherein, when viewed in a direction from the front end to the rear end of the vehicle, the air guide portion is disposed ahead of and adjacent to the vortex portion, and the transition angle between the air guide portion and the vortex portion is at least 45 degrees, for example, at least 60 degrees, at the transition line between the air guide portion and the vortex portion. The external structure is adapted to generate an air vortex adjacent to the vortex portion when the vehicle moves forward.

[0030] The present invention also relates to an external structure for a vehicle, adapted to be disposed on the outer side of the vehicle. The vehicle may be, for example, an automobile used on public roads. The external structure includes at least a vortex portion, wherein the vortex portion has a concave, parabolic, or hyperbolic shape. The external structure further includes an air guide portion, wherein, when viewed from the front end to the rear end of the vehicle: the air guide portion is disposed before and adjacent to the vortex portion, and the transition angle between the air guide portion and the vortex portion is at least 45 degrees, for example, at least 60 degrees, at the transition line between the air guide portion and the vortex portion. The external structure is adapted to generate an air vortex adjacent to the vortex portion as the vehicle moves forward.

[0031] The external structure can be arranged, for example, on the upper, left, or right side of the vehicle. Air vortices generated near the vortex portion can help reduce aerodynamic drag as the vehicle moves. It will be understood that any features or embodiments explained herein with respect to the bottom structure according to the invention or a vehicle including such a bottom structure can also be applied to the external structure according to the invention or a vehicle including such an external structure.

[0032] This invention further relates to a method for achieving one or more of the objectives of the invention. This method can be performed using a vehicle or underbody structure according to the invention, but is not limited thereto. However, any features explained herein with respect to a vehicle or underbody structure of the invention can be similarly applied to the method according to the invention, and vice versa. Unless otherwise expressly stated, the features and definitions explained with respect to a vehicle or underbody structure of the invention will be interpreted in the same manner with respect to the method according to the invention.

[0033] The present invention relates to a method for operating a vehicle, wherein the vehicle includes a bottom structure comprising at least a vortex portion that slopes upward when viewed from the front to the rear of the vehicle, wherein optionally, the vortex portion substantially covers the width of the vehicle. The method includes the steps of: moving the vehicle forward; and generating a bottom air vortex below the vortex portion of the bottom structure while the vehicle is moving forward. Attached Figure Description

[0034] The invention is described below with reference to the accompanying drawings. These drawings are used as examples to illustrate the invention and are not to be construed as limiting the scope of the claims. In different drawings, the same features are indicated by the same reference numerals.

[0035] In the attached diagram:

[0036] Figure 1a Examples of vehicles that violate the departure angle rule.

[0037] Figure 1b The example vehicle illustrates the potential negative impacts on the departure angle.

[0038] Figure 2 This illustrates a first embodiment of the present invention.

[0039] Figure 3 The second embodiment of the present invention is illustrated schematically.

[0040] Figures 4a-4c The vehicle according to the invention is illustrated from different views. Detailed Implementation

[0041] Figure 1a The rear 21 of vehicle 1 is shown, which is arranged on ground 5, which is a horizontal surface in the case shown. Vehicle 1 is an automobile used on public roads. Vehicle 1 includes a superstructure 24 and a bottom structure 25. The bottom structure 25 is arranged at the rear bottom of vehicle 1, between the rear wheel 23 and the rear end 22.

[0042] The aerodynamic profile is illustrated by arrows 11, 12, 13, and 14. The aerodynamic profile illustrates how the air moves as vehicle 1 moves forward. It will be understood that, for clarity, the aerodynamic profile shown in the figure is simplified. The aerodynamic profile includes an upper airflow 11 and a lower airflow 14, wherein the surrounding air flows along... Figure 1a The airflow flows in the directions indicated by arrows 11 and 14. The upper airflow 11 flows along the upper structure 24 of the vehicle 1 until the rear end 22 of the vehicle 1. The lower airflow 14 flows along the lower structure 25 of the vehicle 1 until the rear end 22 of the vehicle 1. At the rear end 22 of the vehicle 1, the upper airflow 11 and the lower airflow 14 separate from the vehicle 1.

[0043] To minimize aerodynamic drag, an aerodynamic profile resembling a teardrop shape is desired. At the rear 21 of vehicle 1, this means that the upper airflow 11 and the lower airflow 14 should converge towards each other as smoothly as possible. The upper structure 24 and the lower structure 25 are arranged to guide the upper airflow 11 and the lower airflow 14 towards a smooth convergence towards each other.

[0044] Behind the rear end 22 of vehicle 1, the aerodynamic profile further includes a rear upper vortex 12 and a rear lower vortex 13. In the rear upper vortex 12 and the rear lower vortex 13, air flows along... Figure 1a The airflow flows in the directions indicated by arrows 12 and 13. For example, the upper rear vortex 12 and the lower rear vortex 13 can be formed due to the shape of the rear end 22 of the vehicle 1. The upper rear vortex 12 causes the upper airflow 11 to flow above the upper rear vortex 12, thereby flowing substantially in the direction along which the upper airflow 11 flows above the upper structure 24. The lower rear vortex 13 causes the lower bottom airflow 14 to flow below the lower rear vortex 13, thereby flowing substantially in the direction along which the lower bottom airflow 14 flows below the lower bottom structure 25. Figure 1a The aerodynamic profile of vehicle 1 shown is relatively advantageous, with relatively low aerodynamic friction and a low drag coefficient.

[0045] Besides the aerodynamic profile, another requirement for the design of the rear 21 of vehicle 1 is the desired departure angle 32. The desired departure angle 32 is the angle between the desired departure line 31 and a horizontal surface, in this case, the ground 5. The desired departure line 31 is a virtual line tangent to the rear wheel 23 and pointing towards the rear end 22 of vehicle 1. The desired departure angle 32 and the desired departure line 31 are defined according to the intended application of vehicle 1, particularly non-flat surfaces on which vehicle 1 should be maneuverable. For example, since vehicle 1 is a car used on public roads, it must be able to drive over speed bumps and enter and exit parking garages. Therefore, the desired departure angle 32 can be 10-20 degrees. A larger desired departure angle 32 can be chosen when vehicle 1 is envisioned driving on off-road surfaces. A smaller desired departure angle 32 can be chosen when vehicle 1 is attempting to drive on a racetrack. To ensure that the underbody structure 25 does not contact the non-flat surface, the underbody structure 25 should be above the desired departure line 31. As can be seen, this is not... Figure 1a The situation of vehicle 1 shown.

[0046] Figure 1b Vehicle 2 is shown with a bottom structure 26 above the desired departure line 31. Other features of vehicle 2 are... Figure 1a The features of vehicle 1 shown in the diagram correspond to those of vehicle 1, therefore in Figure 1b The same reference numerals are used to denote them in the accompanying drawings. To ensure that the bottom structure 26 is above the desired departure line 31, the bottom structure 26 and... Figure 1a The bottom structure 25 in the middle slopes upwards more. For example... Figure 1b As can be seen, the bottom airflow 14 flows again along the bottom structure 26 until it reaches the rear end 22 of the vehicle 2, where the rear end is in a more upward-sloping direction. Furthermore, because the bottom structure 26 is higher at the rear end 22, the rear lower vortex 13 and... Figure 1a It was installed at a higher level. This had an impact. Figure 1b The upper vortex 12 and the upper airflow 11 are visible. Figure 1b The aerodynamic profile in it is not like Figure 1a The aerodynamic profile in it is so similar to a teardrop shape. Specifically, Figure 1b The bottom airflow 14 in the vehicle 2 slopes upward at the point where the bottom structure 26 begins to slope upward, and the upper airflow 11 slopes upward at the rear end 22 of the vehicle 2. This increases the downforce of the vehicle and increases wind resistance. Figure 1bThe aerodynamic profile of vehicle 2 shown results in relatively poor pressure recovery at the rear of the vehicle, which leads to lower aerodynamic pressure at the rear of the vehicle and thus a high drag coefficient.

[0047] It is evident from the above explanation that aerodynamic drag and departure angle can cause conflicts in vehicle design requirements. The inventors have discovered a way to meet these conflicting requirements, or at least provided an alternative. Figure 2 The rear portion 121 of a vehicle 101 according to a first embodiment of the present invention is shown. The vehicle 101 is disposed on a ground 105, which is a horizontal surface in the case shown. The vehicle 101 is an automobile used on a public road. The vehicle 101 includes an upper structure 124 and a lower structure 125. The lower structure 125 is disposed on the rear bottom side of the vehicle 101, between the rear wheel 123 and the rear end 122.

[0048] The bottom structure 125 includes a vortex portion 126. When viewed in a first direction d1, the vortex portion 126 slopes upwards. The first direction d1 is defined as a horizontal direction from the front end of vehicle 101 to the rear end 122 of vehicle 101. Although not visible, the vortex portion 126 substantially covers the width of vehicle 101. The width is defined in a second direction d2, which is a horizontal direction perpendicular to the first direction d1. The bottom structure 125 forms the bottom of vehicle 101, meaning that when viewed in a third direction d3, which is a vertical direction, there are no components of vehicle 101 between the ground 105 and vehicle 101.

[0049] Figure 2 Departure line 131 is further illustrated. Departure line 131 is defined as a virtual line extending from ground plane 105 toward the rear end 122 of vehicle 101 and tangent to the rear wheel 123. Departure angle 132 is defined as the angle between the horizontal plane and departure line 132. The departure angle is at least 10 degrees. A vortex portion 126 of the underbody structure 126 is arranged above departure line 132. Therefore, vehicle 101 satisfies departure angle 132, and when vehicle 101 maneuvers on a intended non-flat surface, underbody structure 125 will not contact the ground.

[0050] The bottom structure 125 is adapted to generate a bottom air vortex 115 when the vehicle 101 moves forward. The bottom air vortex 115 is located below the vortex portion 126 of the bottom structure 125. In the bottom air vortex 115, air flows in the direction of arrow 115. Therefore, the aerodynamic profile of the vehicle 101 includes an upper airflow 111, a bottom airflow 114, a rear upper vortex 112, a rear lower vortex 113, and a bottom air vortex 115. The bottom airflow 114 flows along the bottom structure 125 along an air guide portion 127 arranged before the vortex portion 126. Below the vortex portion 126, the bottom air vortex 115 causes the bottom airflow 114 to no longer flow along the bottom structure 125. Instead, the bottom airflow 114 separates from the bottom structure 125 before the rear end 122 of the vehicle 101. The bottom airflow 114 flows below the bottom air vortex 115. The resulting aerodynamic profile is similar to... Figure 1a The aerodynamic profile shown, but Figure 2 The vehicle 101 shown satisfies a departure angle of 132. Furthermore, the bottom air vortex 115 can exceed the departure line 131, as... Figure 2 As can be seen, departure line 131 extends through bottom air vortex 115. Therefore, bottom airflow 114 flows as if bottom structure 125 would exceed departure line 131.

[0051] When from Figure 2 Viewed from the left side, the bottom air vortex 115 is oriented counterclockwise. The air in the bottom air vortex 115 rotates counterclockwise. At the bottom of the bottom air vortex 115, the air flows substantially in the same direction as the bottom airflow 114, i.e., in the first direction d1. Thus, the friction between the bottom airflow 114 and the bottom air vortex 115 is relatively low. At the top of the bottom air vortex 115, the air flows substantially in the propulsion direction of the vehicle 101, which is oriented opposite to the first direction d1. Any friction between the bottom air vortex 115 and the vortex portion 126 at the top of the bottom air vortex 115 results in a frictional force on the vehicle 101 pointing in the propulsion direction of the vehicle 101.

[0052] The bottom air vortex 115 propagates in a second direction d2, which is a horizontal direction perpendicular to the first direction d1. The second direction d2 is directed toward the left or right side of the vehicle 101. The bottom air vortex 115 is therefore oriented tangentially to the vehicle 101.

[0053] Figure 3A schematic diagram of a vehicle 201 according to a second embodiment of the present invention is shown. The vehicle 201 is disposed on ground 205 and includes an upper structure 224 and a lower structure 225. The lower structure 225 is disposed between the rear wheel 223 and the rear end 222 of the vehicle 201. The lower structure 225 includes a vortex portion 226 and an air guide portion 227. When the vehicle 201 moves forward, the lower structure 225 is adapted to generate a bottom air vortex (not shown for clarity) below the vortex portion 226. When viewed from the front end of the vehicle 201 to the rear end 222 of the vehicle 201 in a first direction d1, the air guide portion 227 is disposed before the vortex portion 226. The air guide portion 227 and the vortex portion 226 are adjacent in a transition line 228, which... Figure 3 In the side view, it extends in a direction perpendicular to the paper. A transition angle 229 can be defined, which represents the transition of the bottom structure 225 from the air guide portion 227 to the vortex portion 226. The transition angle 229 is the angle between the virtual extension line 227' and the vortex portion 226 at the transition line 228. The virtual extension line 227' extends in a direction from the air guide portion 227 upward to the transition line 228. The transition angle 229 is at least 45 degrees, preferably at least 60 degrees. Having a relatively large transition angle 229 helps to generate a bottom air vortex below the vortex portion 226 and helps to separate the bottom airflow from the bottom structure 225.

[0054] The vortex portion 226 has a concave shape. This allows a bottom air vortex to be arranged below the vortex portion 226 and to flow at least partially along the shape of the vortex portion 226. This helps to generate a bottom air vortex and reduces aerodynamic friction when the bottom air vortex is present. The vortex portion can be, for example, parabolic in shape with a hyperbolic shape.

[0055] Figure 3 The vortex portion 226 is further shown to be inclined upwards at an average tilt angle 226a. A virtual average tilt line 226b may be defined between the transition line 228 and the rear end of the vortex portion 226. Figure 3 In the process, the rear end of the vortex section 226 is arranged at the rear end 222 of the vehicle 201. The average tilt angle 226a is defined as the angle between the average tilt line 226b and the horizontal line 226c.

[0056] exist Figure 3 In the illustrated embodiment, the air guide portion 227 is also tilted upwards. A virtual average air guide portion tilt line 227b can be defined between the front end of the air guide portion 227 and the transition line 228. Figure 3 In the state shown, because the air guide section 227 is a flat structure arranged at an angle, so from Figure 3In a side view, the average air guide slope line 227b coincides with the air guide portion 227. In other embodiments, the air guide portion 227 may be a concave or convex structure, which may be determined, for example, according to the desired downforce. The average air guide slope angle 227a may be defined between the average air guide slope line 227b and the horizontal line 227c. The average air guide slope angle 227a is smaller than the average slope angle 226a.

[0057] Figures 4a-4c A third embodiment of the vehicle 301 according to the present invention is shown. Figure 4a The rear view is shown. Figure 4b A rear perspective view is shown. Figure 4c A rear bottom perspective view is shown. Vehicle 301 includes an upper structure 324 and a bottom structure 325. The bottom structure 325 is arranged around the rear wheel 323 of vehicle 301. Figure 4a The bottom structure 325 includes a vortex portion 326 and an air guide portion 327. Below the vortex portion 325, as the vehicle 301 moves forward, a bottom air vortex (not shown for clarity) is generated. The air guide portion 327 abuts the vortex portion 326 at a transition line 328. The transition angle between the air guide portion 327 and the vortex portion 326 at the transition line 328 is at least 45 degrees, preferably at least 60 degrees.

[0058] exist Figure 4c The diagram indicates that transition line 328 includes a left portion 328a, a central portion 328b, and a right portion 328c. The central portion 328b extends substantially in a direction from the left side of vehicle 301 to the right side of vehicle 301. The left portion 328a and the right portion 328c of transition line 328 are partially curved and extend partially toward the rear end 322 of vehicle 301.

[0059] A portion of the bottom airflows 314a, 314b, 314c guided upward to transition line 328 is indicated by arrows 314a, 314b, 314c. The bottom airflows 314a, 314b, 314c comprise air flowing from the front end of vehicle 301 to the rear end 322 of vehicle 301 below vehicle 301. Below bottom structure 325, the bottom airflows 314a, 314b, 314c flow substantially upward along air guide portion 327 to transition line 328. Below vortex portion 326, a bottom air vortex is generated. The bottom airflows 314a, 314b, 314c separate from bottom structure 325 at transition line 325 and flow below the bottom air vortex.

[0060] The approach angle can be defined at the transition line 328. The approach angle is the angle at which the bottom airflows 314a, 314b, and 314c approach the transition line 328. The approach angle depends on how the bottom airflows 314a, 314b, and 314c are guided below the air guide section 327 and the shape of the transition line 328. Generally, the closer the approach angle is to 90 degrees, the larger the bottom air vortex generated below the vortex section 326. Therefore, the air guide section 327, the vortex section 326, and the transition line 328 are designed such that the approach angle is 60-120 degrees.

[0061] At the central portion 328b of transition line 328, the central portion 314b of the bottom airflow is guided toward transition line 328 in a manner substantially perpendicular to transition line 328. At the curved left and right portions 328a and 328c of transition line 328, where the left and right portions 314a and 314c are respectively close to transition line 328, the approach angle deviates further by 90 degrees. Therefore, the bottom air vortex below the central portion 326b of vortex portion 326 is larger than the bottom air vortex below the left and right portions 326a and 326c of vortex portion 326. This reduces the influence of the bottom air vortex on the lateral airflow including the air flowing on the left and right sides of vehicle 301.

[0062] Figure 4c The bottom structure 325 is further shown to include a diffuser 330. The diffuser 330 improves the integration of the bottom airflows 314a, 314b, 314c with other airflows behind the rear end 322 of the vehicle 301.

[0063] Figures 4a-4c The vehicle 301 shown is an electric vehicle, including an electric motor as a thrust source. The driving range of vehicle 301 is improved due to the underbody structure 325. Furthermore, no exhaust system is needed at the rear end 322 of vehicle 301 to discharge exhaust gases from the internal combustion engine. The underbody structure 325, particularly the vortex section 326, can be designed without considering an exhaust system. Moreover, exhaust gases could adversely affect airflow behind the vehicle.

[0064] The vehicle's superstructure 324 includes a roof 351 and a rear upper side 352. In some embodiments, the rear upper side 352 may be a window. In some embodiments, solar panels may be disposed on the roof 351 and / or the rear upper side 352. The solar panels may be used to provide power to an electric motor, for example, to power a battery.

[0065] Figure 3An example is shown where the rear length 241 of vehicle 201 can be defined as the distance between the axle 223a of the rear wheel 223a and the rear end 222. The rear length 241 is relatively long. As the rear length 241 of vehicle 201 increases, a departure angle violation is more likely. On the other hand, a larger rear length 241 may be advantageous for aerodynamic profiles and can, for example, provide more space for arranging solar panels. The present invention helps to satisfy this conflicting requirement.

[0066] Detailed embodiments of the invention have been disclosed herein as needed; however, it should be understood that the disclosed embodiments are merely examples of the invention, which can be implemented in various forms. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as the basis for the claims and as a representative basis for teaching those skilled in the art to employ the invention differently with virtually any suitable detailed structure. Furthermore, the terminology and phrases used herein are not intended to be limiting, but rather to provide an understandable description of the invention.

[0067] As used herein, the terms "a" or "an" are defined as one or more. As used herein, terms include and / or have are defined as including (i.e., open-ended language, not excluding other elements or steps). Any reference numerals in the claims should not be construed as limiting the scope of the claims or the invention.

[0068] The mere fact that certain measures are described in mutually different dependent claims does not imply that combinations of these measures cannot be used advantageously.

[0069] A single processor or other unit can perform the functions of several items recited in the specification and claims, such as the functions of a control unit. According to known methods, any communication between features can be wired or wireless.

[0070] The method according to the present invention can be implemented as a program, computer program, or software application, etc. A program, computer program, or software application may include subroutines, functions, procedures, object methods, object implementations, executable applications, applets, service applets, source code, object code, shared libraries / dynamically loaded libraries, and / or other sequences of instructions designed for execution on a computer system.

[0071] Computer programs may be stored and / or distributed on suitable media, such as optical storage media or solid-state media provided with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems.

Claims

1. A vehicle including a bottom structure disposed at the rear bottom side of the vehicle, wherein the vehicle is an automobile used on public roads, wherein the bottom structure: It includes at least a vortex portion that, when viewed in a first direction from the front end to the rear end of the vehicle, tilts upwards. • Suitable for generating a bottom air vortex below the vortex portion when the vehicle moves forward. Furthermore, the departure line is defined as a virtual line extending from the ground plane toward the rear end of the vehicle and tangent to the rear wheels. in: ●The bottom structure is arranged above the departure line, and ●The bottom air vortex exceeds the departure line.

2. The vehicle of claim 1, wherein the bottom air vortex is adapted to propagate in a second direction oriented substantially perpendicular to the first direction.

3. The vehicle according to claim 1 or 2, wherein the bottom air vortex is oriented counterclockwise when viewed from the left side of the vehicle.

4. The vehicle of claim 1, wherein the departure angle is defined as the angle between the horizontal plane and the departure line, wherein the departure angle is at least 10 degrees.

5. The vehicle according to claim 1 or 2, wherein the underbody structure further includes an air-guiding portion, wherein when viewed in a direction from the front end to the rear end of the vehicle: ● The air guide portion is arranged before the vortex portion and adjacent to the vortex portion at the transition line. ● The transition angle between the air guide portion and the vortex portion is at least 45 degrees at the transition line.

6. The vehicle of claim 5, wherein the air guiding portion and the vortex portion are adapted to guide bottom airflow toward the transition line at an approach angle of 60-120 degrees with respect to the transition line.

7. The vehicle of claim 5, wherein the vortex portion is arranged at an average tilt angle, and the air guide portion is arranged at an average air guide portion tilt angle, wherein the average tilt angle is greater than the average air guide portion tilt angle.

8. The vehicle according to claim 1 or 2, wherein the vortex portion has a concave shape.

9. The vehicle according to claim 1 or 2, wherein the vortex portion has a hyperbolic or parabolic shape.

10. The vehicle according to claim 1 or 2, wherein the bottom air vortex is larger below the center of the vortex portion than below the left and / or right portions of the vortex portion, and the left and / or right portions of the vortex portion are the outer ends of the vortex portion when viewed in the width direction of the vehicle.

11. The vehicle according to claim 1 or 2, further comprising a diffuser arranged in front of the vortex portion when viewed in a direction from the front end to the rear end of the vehicle.

12. The vehicle according to claim 1 or 2, wherein the vehicle is an automobile that includes an electric motor as a propulsion source.

13. The vehicle according to claim 1 or 2, wherein the vehicle includes a solar panel on the roof and / or upper rear side of the vehicle.

14. The vehicle of claim 1, wherein the vortex portion covers the width of the vehicle.

15. A bottom structure for a vehicle, adapted to be disposed at the rear side of the bottom of the vehicle to form the rear bottom of the vehicle, wherein the bottom structure: • Includes at least a vortex portion, which, when the bottom structure is arranged on the vehicle, tilts upward when viewed from the front to the rear of the vehicle. • Suitable for generating a bottom air vortex below the vortex portion when the vehicle moves forward, and wherein the departure line is defined as a virtual line extending from the ground plane toward the rear end of the vehicle and tangent to the rear wheel. in: ●The bottom structure is adapted to be positioned above the departure line, and ●The bottom air vortex exceeds the departure line.

16. The underbody structure for a vehicle according to claim 15, wherein the vortex portion covers the width of the vehicle.

17. A vehicle including an external structure disposed on the outer side of the vehicle, wherein the vehicle is an automobile used on public roads, wherein, The external structure: It includes at least a vortex portion, wherein the vortex portion has a concave, parabolic, or hyperbolic shape. • Includes an air-guiding section, wherein when viewed in a direction from the front end to the rear end of the vehicle: i. The air guiding portion is arranged before and adjacent to the vortex portion, and ii. The transition angle between the air guide portion and the vortex portion is at least 45 degrees at the transition line between the air guide portion and the vortex portion. ●Suitable for generating air vortices adjacent to the vortex portion when the vehicle moves forward, wherein the departure line is defined as a virtual line extending from the ground plane toward the rear end of the vehicle and tangent to the rear wheel. in: ●The external structure is adapted to be arranged above the departure line, and ●The air vortex exceeds the departure line.

18. A method for operating a vehicle, wherein the vehicle includes a bottom structure, the bottom structure including at least a vortex portion that, when viewed in a direction from the front end to the rear end of the vehicle, is inclined upwards. The method includes the following steps: ● Move the vehicle forward. As the vehicle moves forward, a bottom air vortex is generated below the vortex portion of the bottom structure. Furthermore, the departure line is defined as a virtual line extending from the ground plane toward the rear end of the vehicle and tangent to the rear wheels. in: ●The bottom structure is adapted to be positioned above the departure line, and • The bottom air vortex exceeds the departure line.

19. The method for operating a vehicle according to claim 18, wherein the vortex portion covers the width of the vehicle.

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