Air guiding device of an air flow duct

Abstract

Air guiding device (2) of an air flow duct (30), wherein the air guiding device (2) has a plurality of passage openings (21, 21', 21''), characterized by that each passage opening (21, 21', 21'') is designed as a passage channel which has an upstream mouth (23, 23', 23'') with a first mouth surface having a first area center of gravity (A, A', A'') and an downstream mouth (24, 24', 24'') with a second mouth surface having a second area center of gravity (B, B', B''), and that the connecting lines (c, c', c'') between the respective upstream area centre of gravity (A, A', A'') and the respective downstream area centre of gravity (B, B', B'') of mutually adjacent passage openings (21, 21', 21'') do not run parallel.

Description

TECHNICAL FIELD

[0001] The invention relates to an air guiding device of a flow channel according to the preamble of patent claim 1. It further relates to a motor vehicle with at least one such air guiding device. BACKGROUND OF THE INVENTION

[0002] Ventilation grilles, particularly those in a vehicle's exterior skin, generally serve to allow air to pass through while simultaneously preventing large foreign bodies from entering a space located behind the grille. Conventional ventilation grilles, such as those found in the front panel of a vehicle body or, in the case of rear-engine vehicles, in the rear area of ​​the vehicle, create a significant flow resistance for the air flow passing through the grille.Particularly when the ventilation grille is not directly exposed to the airflow, as is the case with a radiator grille, for example, but rather when the airflow has flowed along an area of ​​the vehicle's outer skin before reaching the ventilation grille, these flow resistances can become greater, as the opening direction of the ventilation grille is then often different from the direction of the airflow flowing around the vehicle's outer skin. Therefore, thin, perforated panels are often used for such ventilation grilles to offer as little flow resistance to the airflow as possible. However, this has the disadvantage that air passing through the ventilation grille largely retains the directional vector of the airflow hitting the ventilation grille. Targeted flow deflection is not possible with such ventilation grilles. DESCRIPTION OF THE INVENTION

[0003] The object of the present invention is to provide a generic air guiding device for an air flow duct, which has a plurality of through-openings and in which the individual through-openings offer reduced flow resistance to a flow field of an air flow impinging on the air guiding device. Furthermore, the object of the present invention is to provide a vehicle with such an air guiding device and a method for producing such an air guiding device.

[0004] The part of the problem directed at the air guiding device is solved with the features of patent claim 1.

[0005] An air guiding device of an air flow duct, which has a plurality of passage openings, is characterized according to the invention in that each passage opening is designed as a passage channel which has an upstream opening with a first mouth surface having a first area centroid and an downstream opening with a second mouth surface having a second area centroid, and in that the connecting lines between the respective upstream area centroid and the respective downstream area centroid of mutually adjacent passage openings do not run parallel. ADVANTAGES

[0006] This inventive design of the air guiding device makes it possible to shape the shape of the individual passage openings, i.e. the shape of the walls separating the individual passage openings from one another, in such a way that the main passage direction for a flow through the respective passage opening is aligned substantially in the direction of the flow vector of the air flow flowing towards the respective passage opening, so that the respective flow resistance of the individual passage openings is minimized.

[0007] Advantageous further developments of the invention are specified in subclaims 2 to 6.

[0008] Preferably, the air guiding device is designed in a grid-like manner and has a plurality of passage openings arranged one-dimensionally or two-dimensionally next to one another in a plane.

[0009] It is advantageous if the connecting line between the upstream center of gravity and the downstream center of gravity forms a straight line.

[0010] In another advantageous embodiment of the invention, the connecting line connecting the upstream-side area center of gravity with the downstream-side area center of gravity runs through an area center of gravity of at least one further cross-sectional area of ​​the passage channel located between the first mouth surface and the second mouth surface.

[0011] The connecting line preferably forms a curve that deviates from a straight line.

[0012] Preferably, the connecting lines between adjacent passage openings have different curves.

[0013] The part of the problem directed at the motor vehicle is solved by the motor vehicle having the features of patent claim 7.

[0014] By using at least one air guiding device designed according to the invention in a motor vehicle, the flow resistance of the motor vehicle and thus its energy consumption can be significantly reduced. Furthermore, a reduction in flow noise in the motor vehicle can also be expected.

[0015] It is particularly advantageous if the air guiding device is provided in an area of ​​the vehicle's outer skin where the air guiding device is exposed to an air flow that previously flowed along an area of ​​the vehicle's outer skin, and if the connecting lines of the individual passage openings are directed substantially parallel to the directional vector of the incoming air flow immediately in front of the respective passage opening. This embodiment ensures particularly low flow resistance of the air guiding device and thus reduced vehicle aerodynamic drag.

[0016] The part of the problem directed to the method is solved by a method having the features of patent claim 9.

[0017] The additive manufacturing of at least the structure of an air guiding device surrounding the passage openings or of the entire air guiding device makes it possible to produce the air guiding device according to the invention cost-effectively without having to manufacture and use complicated and multi-part injection molds.

[0018] Preferred embodiments of the invention with additional design details and further advantages are described and explained in more detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] It shows: Fig. 1 a rear view of a motor vehicle designed according to the invention, Fig. 2 an exploded view of an air duct arrangement with an air guiding device according to the invention designed as a ventilation grille, Fig. 3 the air guiding device Fig. 2 in enlarged top view and Fig. 4 an enlarged perspective view of a section of an air guiding device according to the invention. PRESENTATION OF PREFERRED EMBODIMENTS

[0020] Fig. 1 shows the rear view of a vehicle 1 configured according to the invention, comprising a vehicle body 12 having an outer vehicle skin 11 and a rear-mounted engine (not shown) arranged in an engine compartment provided at the rear of the vehicle. To supply the engine with combustion air, air guiding devices 2 are provided to the left and right of a rear window 10, which guide a portion of the air flowing around the vehicle body 12 along the outer vehicle skin 11 to the engine. The inventive design of the air guiding device 2, which will be described in more detail below, makes it possible to guide the portion of the air flowing around the vehicle that is diverted for the engine through the air guiding device to the engine as smoothly as possible and without significant flow resistance.

[0021] Fig. Figure 2 shows a schematic exploded view of the structure of an air duct arrangement, namely an air flow duct housing 3 provided with the air guiding device 2, which has an air flow duct 30 divided into individual duct sections 34 by a plurality of rib-like guide vanes 32. On the upstream side, an air collection chamber 31 is formed in the air flow duct housing 3, into which the air flow duct 30 opens. The outwardly open air collection chamber 31 is covered by the air guiding device 2, so that air can enter the air collection chamber 31 through the air guiding device 2, but larger foreign bodies are prevented from entering the air flow duct 30.

[0022] Fig. 3 shows a plan view of the air guiding device 2 designed according to the invention. The air guiding device 2 essentially consists of an air guiding device body 20 which has a plurality of passage openings 21, 21', 21" through which air can enter from outside into the collecting space 31 of the air flow duct housing 3.

[0023] The passage openings 21, 21', 21'' in the example shown are of different cross-sectional shape and irregular size, so that, for example, the Fig. 3. The passage openings 21, 21', 21'' are each surrounded by a wall 22, 22', 22'', each of which defines a passage channel for the air. The structural framework of the air guiding device 2, which forms the walls 22, 22', 22'' of the individual passage openings 21, 21', 21'', is also irregular, both with regard to the directional course of the individual walls 22, 22', 22'', the inclination of the individual walls 22, 22', 22'' relative to the surface of the air guiding device 2 and, for example, also with regard to the thickness course of the walls 22, 22', 22'', which can lead to different wall thicknesses of the wall structure.

[0024] The structure of the passage channels and the shape of the individual passage openings 21, 21', 21'' are described below with reference to the Fig. 4 described in detail. The passage openings 21, 21', 21'' forming the passage channels each have an upstream opening 23, 23', 23'' and a downstream opening 24, 24', 24''. Each upstream opening 23, 23', 23'' has a first, upstream opening surface with a first area center of gravity A, A', A''. Similarly, each downstream opening 24, 24', 24'' has a second, downstream opening surface with a second area center of gravity B, B', B''.

[0025] The connecting lines c, c', c'' of the respective first centroid A, A', A'' with the respective second centroid B, B', B'' run as in Fig. 4, in different directions and thus not parallel to one another. By appropriately designing the shape and inclination of the respective wall 22, 22', 22'', a geometry of the respective passage opening 21, 21', 21'' can be designed in which the respective connecting line c, c', c'' of the upstream area centroids A, A', A'' with the respective downstream area centroids B, B', B'' is adapted to the course of the flow impinging on the respective passage opening 21, 21', 21'', i.e. the respective main flow vector of the portion of the air flowing around the vehicle outer skin 11 entering the respective passage opening 21, 21', 21''. Such an alignment of the respective passage opening 21, 21', 21'', which is individually adapted to the flow pattern, considerably reduces the flow resistance for the air passing through the air guiding device 2.

[0026] The respective connecting line c, c', c'' can, as in the example of Fig.4 is shown in simplified form, be designed as a straight line. In more complex embodiments of the respective passage openings 21, 21', 21'' and their associated wall 22, 22', 22'', the connecting line c, c', c'' can also form a curve deviating from a straight line, for example if the course of the wall is curved in the flow direction, in which case the connecting line c, c', c'' additionally runs through a centroid of at least one further cross-sectional area of ​​the passage channel located between the first opening surface and the second opening surface. In this case, the connecting line c, c', c'' does not connect the upstream area centroid A, A', A'' with the downstream area centroid B, B', B'' via the shortest path, but rather via a detour via a centroid (not shown) of the cross-sectional area of ​​the passage channel located therebetween (not shown).In this variant, it is even possible that the connecting lines c, c', c'' of adjacent passage openings 21, 21', 21'' not only extend in different directions, but also have different curve profiles.

[0027] The complex shape of the air guiding device 2 with its passage openings 21, 21', 21'' oriented in different directions can be produced particularly well using a generative manufacturing process, i.e., by additive material construction, which includes, for example, a 3D printing process. However, other additive material construction processes are also suitable for producing the complex structure of the air guiding device 2 according to the invention.

[0028] The air guiding device 2 according to the invention thus forms a functionally optimized, aerodynamically optimized, and design-optimized ventilation grille, which is preferably manufactured using an additive manufacturing process. This allows for greater flexibility in the design and layout of the components, since even the most complex shapes and undercuts can be manufactured without regard to tools or demoldability. For this reason, additive manufacturing is particularly suitable for such air guiding elements.

[0029] The air duct arrangement, which is improved compared to the prior art, can be manufactured either from three separate parts: the air flow duct housing 3 with the chimney-like air flow duct 30 for lower flow guidance, the perforated plate-like air guide device 2 for covering the air collection chamber 31, and the arrangement of air guide vanes 32 inserted as a separate component into the air flow duct 30, or as a single component that integrates the three aforementioned components. Furthermore, the perforated plate-like air guide device 2 can also be arranged below the arrangement of air guide vanes 32, as an alternative to the example shown.

[0030] The perforated sheet-like air guiding device 2 can be designed in the form of a bionic design. Furthermore, the generative production of the air guiding device 2 allows for a special interplay of appearance and function, allowing for greater design freedom, since the design does not require consideration of the manufacturing process.

[0031] The additively manufactured (e.g. 3D-printed) perforated sheet-like air guiding device contains deep holes as passage openings for the air flow, which have an optimized angle of attack according to the air flow. By individually adjusting the hole orientation, optimal air flow into the air flow channel and onto downstream air guiding elements (not shown) can be achieved. Furthermore, small air scoops can be provided on the individual passage openings 21, 21', 21'', which guide the incoming air into the passage openings 21, 21', 21'' and thereby enable a larger air mass flow. These individually adjusted hole orientations of the passage openings 21, 21', 21'' can be produced using additive manufacturing processes, since demolding this geometry from an injection mold would not be possible.The shape of the holes can be, for example, round, triangular, square, pentagonal, hexagonal or take on a free form.

[0032] As a further feature, boundary layer extraction can be provided on the surface of the air guiding device 2 or the guide vanes 32, which can further influence and improve aerodynamics. The inlets and the flow channels required for boundary layer extraction can be optimally incorporated using additive manufacturing processes at the calculated locations within the component walls, e.g. the walls 22, 22', 22'' surrounding the passage openings 21, 21', 22'', thus eliminating the need for additional external flow channels. The air extracted during boundary layer extraction can be used either to cool the engine compartment or to influence aerodynamics at other locations. Boundary layer extraction enables a laminar flow that lasts for a longer period, which can, for example, reduce the drag coefficient.

[0033] The air guiding device 2 and also the guide vanes 32 can be optimally designed for the flow through production using additive manufacturing processes, without having to consider the manufacturability by injection molding. This means that the guide vanes 32 can also have undercuts or more complex geometries of the walls 22, 22', 22'' and the guide vanes 32 can be implemented. The optimized flow guidance can increase and direct the incoming air mass, thus improving the cooling of the components in the engine compartment. In addition, the adapted aerodynamics may result in a lower pressure loss, which simultaneously improves the vehicle's drag coefficient and allows a higher flow velocity of the cooling air to be achieved. The direction of the flow can also be optimized for improved cooling.

[0034] Additionally, the application of an additive 4D manufacturing process or the use of so-called "smart materials" is conceivable, allowing geometries to be produced that change over time. This allows for the creation of adaptive air intakes that can change the amount of incoming air by opening and closing the passage openings 21, 21', 21'' in the air guiding device 2 depending on the driving speed and / or temperature of the engine compartment. Changing the angle of attack of the guide vanes 32 using smart materials is also conceivable. This allows for further improved optimal cooling of the engine compartment at all times, while simultaneously improving aerodynamics.

[0035] It is also possible to manufacture the air guiding device 2 using conventional additive 3D manufacturing processes, wherein the control of any aeroelastic elements provided for opening and closing the passage openings 21, 21', 21'' or for adjusting the angle of attack of the air guiding vanes 32 can be carried out, for example, by actuators.

[0036] The materials used for the air guiding device 2 can be, for example, plastic, fiber-reinforced plastic, metal or ceramic, whereby material combinations between or within the components are also possible.

[0037] By manufacturing these components using an additive manufacturing process, they can also be made hollow at any location, which saves weight compared to the previously used injection molding process. This allows, for example, the air guide vanes 32 to be manufactured hollow or flow channels for boundary layer extraction to be integrated.

[0038] The invention achieves the following advantages: - Improved compromise between optimized aerodynamics (low drag coefficient) and optimal cooling - Optimization of aerodynamic function while maintaining design freedom - Symbolization of sustainability through bionic design possible - Optimized flow guidance through individual angle of attack of the holes in the air guide device - Weight savings possible through the production of hollow components.

[0039] The invention is not limited to the above embodiment, which merely serves to generally explain the core concept of the invention. Within the scope of protection, the device according to the invention may also take on embodiments other than those described above. In particular, the device may have features that represent a combination of the respective individual features of the claims.

[0040] Reference signs in the claims, the description and the drawings serve only to improve the understanding of the invention and are not intended to limit the scope of protection. List of reference symbols 1 vehicle 2 air guiding device 3 air flow duct housing 10 rear windows 11 Vehicle outer skin 12 Vehicle body 20 air deflector bodies 21 Passage opening 21' passage opening 21'' passage opening 22 wall 22' wall 22'' wall 23 upstream mouth 23' upstream mouth 23'' upstream outlet 24 downstream mouth 24' downstream mouth 24'' downstream outlet 30 Air flow channel 31 Air collection chamber 32 guide vanes 34 canal sections A upstream centroid A' upstream centroid A'' upstream center of gravity B downstream centroid B' downstream centroid B'' downstream centroid c connecting line c' connecting line c'' connecting line

Claims

[1] Air guiding device (2) of an air flow duct (30), wherein the air guiding device (2) has a plurality of passage openings (21, 21', 21''), characterized by , that each passage opening (21, 21', 21'') is designed as a passage channel which has an upstream mouth (23, 23', 23'') with a first mouth surface having a first area center of gravity (A, A', A'') and an downstream mouth (24, 24', 24'') with a second mouth surface having a second area center of gravity (B, B', B''), and that the connecting lines (c, c', c'') between the respective upstream area centre of gravity (A, A', A'') and the respective downstream area centre of gravity (B, B', B'') of mutually adjacent passage openings (21, 21', 21'') do not run parallel. [2] Air guiding device (2) according to claim 1, characterized bythat the air guiding device (2) is designed like a grid and has a plurality of one-dimensionally or two-dimensionally arranged passage openings (21, 21', 21''). [3] Air guiding device (2) according to claim 1 or 2, characterized by that the connecting line (c, c', c'') of the upstream centroid (A, A', A'') and the downstream centroid (B, B', B'') forms a straight line. [4] Air guiding device (2) according to claim 1 or 2, characterized by that the connecting line (c, c', c'') connecting the upstream area center of gravity (A, A', A'') with the downstream area center of gravity (B, B', B'') runs through an area center of gravity of at least one further cross-sectional area of ​​the passage channel located between the first mouth surface and the second mouth surface. [5] Air guiding device (2) according to claim 4, characterized bythat the connecting line (c, c', c'') forms a curve that deviates from a straight line. [6] Air guiding device (2) according to claim 5, characterized by that the connecting lines (c, c', c'') of adjacent passage openings (21, 21', 21'') have different curve profiles. [7] Motor vehicle (1) with at least one air guiding device (2) according to one of the preceding claims. [8] Motor vehicle (1) according to claim 7, characterized by , that the air guiding device (2) is provided in a region of the vehicle outer skin (11) at which the air guiding device (2) is subjected to an air flow which has previously flowed along a region of the vehicle outer skin (11), and that the connecting lines (c, c', c'') of the individual passage openings (21, 21', 21'') are directed substantially parallel to the direction vector of the incoming air flow immediately in front of the respective passage opening (21, 21', 21''). [9] Method for producing an air guiding device (2) according to one of claims 1 to 6, in which at least the structure surrounding the passage opening (21, 21', 21'') is manufactured by additive material construction, in particular by 3D printing.

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