FR3045000A1 - AERODYNAMIC DEFLECTOR DEVICE FOR A MOTOR VEHICLE WHEEL - Google Patents

Abstract

The invention relates to an aerodynamic deflector device (7) for a motor vehicle wheel, comprising: - a deflecting wall (15) movably mounted on a support (11) between on the one hand a retracted position, in which, in the state mounted said deflector wall (15) is raised relative to the support (11), and secondly an extended position, in which, in the mounted state, said deflector wall (15) is lowered relative to the support (11) and an actuator (19) connected to said baffle wall (15) and configured to move said baffle wall (15) between the retracted and deployed positions.

Description

The invention relates to an aerodynamic deflector device for a motor vehicle wheel.

A constant concern in the automotive field is the fuel consumption and the environmental impact of the vehicle, particularly through its greenhouse gas emissions such as CO2 or toxic gases such as NOx. To reduce fuel consumption, car manufacturers are trying to make more efficient propulsion engines on the one hand and to reduce the consumption of vehicle equipment on the other hand.

An important factor in the consumption of a vehicle is determined by the wind catch or aerodynamics of the vehicle.

Indeed, the aerodynamics of a motor vehicle is an important feature because it influences in particular the fuel consumption (and therefore the pollution) as well as the performance including acceleration of said vehicle.

In particular, the drag or aerodynamic resistance to advancement plays a decisive role, especially at higher speeds, because the drag varies depending on the square of the speed of movement of the vehicle.

According to the models used in fluid mechanics, it is possible, for example, to quantify the drag force exerted on a motor vehicle using a reference surface S. As a first approximation, the drag force, denoted Fx, is equal to q * S * Cx, where q denotes the dynamic pressure (q = 1/2 p * V2, p denoting the density of the air and V the velocity of the vehicle relative to the air), Cx denoting a drag coefficient specific to the vehicle.

The reference surface used for a motor vehicle usually corresponds to its front surface. It is therefore understood that to reduce the drag, it is necessary to aim to reduce the reference surface. The analysis of aerodynamic phenomena in more detail has also brought to light the determining role of vehicle wheels.

Indeed, the wheels can significantly increase the aerodynamic resistance because they generate turbulence when the air flow hits the rotating wheel. At high speeds it has been shown that the front wheels can contribute up to 30% of the reference surface.

Indeed, when a motor vehicle moves, the air in which it evolves is deflected according to the profile of the vehicle. The air thus deviated notably reaches the wheel well. The wheel arch is a cavity in the body of the vehicle, and surrounding a wheel (this corresponds to the wing of the vehicle). The wheel arch fulfills several functions. In particular, it limits (by retaining them) projections of water, mud or other materials on which the wheel is likely to circulate and that it may be caused to expel during its rotation. The air reaching the wheel well circulates in particular in the narrow space between the wheel and the wheel arch. It is known that on this occasion, turbulences are formed around wheel turns and create an aerodynamic brake.

It is known to place a fixed deflector in front of a motor vehicle wheel. Such a fixed deflector, which can take the form of a flap (often about 5cm in height), reduces turbulence in the wheel well.

However, such a fixed deflector may be damaged during obstacle clearance (sidewalk, speed bump type, etc.).

The present invention aims to overcome at least partially some of the disadvantages described above. a deflecting wall mounted movably on a support between a retracted position on the one hand, in which, in the mounted state, said deflecting wall is raised with respect to the support, and on the other hand an extended position in which, at mounted state, said baffle wall is lowered relative to the support, and an actuator connected to said baffle wall and configured to move said baffle wall between the retracted and deployed positions.

Thanks to the movement managed by the actuator, the fixed deflector is no longer likely to be damaged during obstacle crossings.

The aerodynamic deflector device according to the invention may comprise one or more of the following characteristics taken alone or in combination:

The deflecting wall has for example in longitudinal section a form of circular arc whose radius of the arc can substantially correspond to the radius of the wheel well of the vehicle.

According to one aspect, the baffle wall has a cross sectional shape divergent in the direction of the air flow striking said wall.

More specifically, the deflecting wall may have a convex shape in cross section.

In another aspect, the deflecting wall has a straight cross-sectional shape in the direction of the air flow striking said wall.

It is further provided that the carrier is configured to be mounted in the wheel well of a motor vehicle.

In this case, the support may comprise slides configured to be fixed in the wheel well.

According to another embodiment, the support is made as a rectangular frame configured to be fixed to the chassis of a motor vehicle, for example in a housing provided for this purpose upstream of the wheel, and the deflecting wall is pivotally connected to the frame by side walls forming a sector of a circle.

In another aspect, the actuator comprises a rotary output member in direct or indirect engagement with the baffle wall.

The device may further comprise a rack attached to the baffle wall and the output member comprises a pinion meshing with the rack.

In a variant, the output member comprises a wheel provided on its periphery with an elastomer in contact with the baffle wall for driving it.

Finally, the invention relates to a motor vehicle, characterized in that it comprises at least one aerodynamic deflector device as defined above disposed upstream of a vehicle wheel. Other advantages and features will become apparent upon reading the description of the invention, as well as the accompanying drawings, in which: FIGS. 1A and 1B show side diagrams of the aerodynamic deflector device according to a first embodiment in two positions 2A and 2B show a simplified diagram of the aerodynamic deflector device of FIGS. 1A and 1B respectively in a side perspective view and a cross-sectional view, FIGS. 3A and 3B show perspective diagrams of the deflector device. according to a second embodiment in two different positions; FIG. 4 shows an exploded perspective diagram of a third embodiment, and FIGS. 5A, 5B and 5C show perspective diagrams of different positions of the deflector device. aerodynamic according to the third embodiment.

In this description, "upstream" means that one element is placed before another relative to the direction of flow of the air flow. On the other hand, "downstream" is understood to mean that one element is placed after another relative to the direction of flow of the air flow. By upper, lower, upper and lower, reference is made to the arrangement of the elements in the figures, which generally corresponds to the arrangement of the elements in the assembled state in a motor vehicle.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined to provide other embodiments.

An LH or LTH mark in a figure indicates respectively the longitudinal (L), transverse (T) and height (H) directions corresponding to the x-y-z directions of the vehicle.

In the description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter and second parameter, or first criterion and second criterion, and so on. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria close but not identical. This indexing does not imply a priority of one element, parameter or criterion with respect to another, and it is easy to interchange such denominations without departing from the scope of the present description. This indexing does not imply an order in time either.

Figure 1A shows a simplified schematic side of a front portion 1 of a motor vehicle, in particular a wheel 3 and a wheel well 5 provided with a wind deflector device 7 wheel.

In the diagram of FIG. 1A, the vehicle moves according to the arrow 9, so that an air flow 10 flows towards the vehicle and the wheel 3 and impacts the vehicle and in particular the wheel 3 in the direction reverse.

With reference to FIGS. 2A and 2B showing a simplified diagram of the aerodynamic deflector device of FIGS. 1A and 1B respectively in a side perspective view and a cross sectional view, the aerodynamic deflector device 7 comprises a support 11 configured to be mounted in the passageway wheel of a motor vehicle.

In the present embodiment, the support 11 is made in the form of two lateral guides 13 configured to be fixed in the wheel well 5, for example by screwing or by staples or any other fastening means.

The aerodynamic deflector device 7 further comprises a deflecting wall 15.

As can be seen in FIGS. 1A, 1B and 2A, this deflecting wall 15 has, in longitudinal section, that is to say, in the length direction of the deflector wall 15, a curved shape, more precisely in an arc in order to be able to integrate the deflecting wall 15 without any problem in the wheel arch 5, it is expected that the radius of the arc of a circle corresponds for example substantially to wheel arch radius 5 of the vehicle.

This deflecting wall 15 is movable between on the one hand a retracted or folded position (see FIG. 1A) and on the other hand a lowered or extended position (see FIG. 1B).

In the retracted position, the deflecting wall 15 is raised in the wheel well 5 and therefore does not obstruct the flow of air 10 impacting the wheel 5.

This retracted position is generally adopted for low speeds, for example less than 50km / h.

Indeed, for small speeds, the effect of the deflecting wall 15 is small, especially with respect to the reference surface.

In addition, it is at speeds below about 50km / h that we cross obstacles such as sidewalks, speed bumps like Donkey, cushion Berlin, etc. By taking the retracted position at these low speeds, the deflecting wall 15 is protected against breakage.

In the lowered or deployed position shown in FIG. 1B, the deflecting wall 15 is placed upstream of the wheel 3 of the vehicle being at least partially below the axis of rotation 17 of said wheel 3. this position lowered or active, that the air flow 10 is deflected so as not to be able to rush into the wheel well 5. This avoids the creation of turbulence in the wheel well 5 which contribute to the increase significant of the reference surface.

Thus, the drag force can be contained at more acceptable values.

To move the baffle wall 15 between the retracted and deployed positions, the aerodynamic deflector device 7 further comprises an actuator 19.

According to the embodiment of FIGS. 1A, 1B and 2A, 2B, the actuator 19 is for example an electric motor and comprises a rotary output member 21 engaged directly or indirectly with the deflecting wall 15.

As can be seen in FIG. 2A, the aerodynamic deflector device 7 comprises a curved rack 23 whose curvature is adapted to that of the deflecting wall 15 to which the rack 23 is fixed. The rotary output member 21 is a pinion which meshes with the rack 23 to move the baffle wall 15 between the retracted and deployed positions. The actuator 19 is for example connected to a control unit 24 comprising for example an electronic circuit such as a microprocessor or a microcontroller receiving a speed information from a speed sensor, and ordering the deployment or retraction of the baffle wall 15 accordingly.

According to one possible implementation, a hysteresis mechanism is provided in order to avoid threshold effects. Thus, it is possible to provide that the control unit 24 triggers the deployment of the deflector wall 15 as soon as the speed exceeds a given threshold (for example 50km / h), but that the retraction of the deflector is triggered only when the speed drops below a threshold below the aforementioned threshold (for example a threshold of 40km / h).

Thus, the circuit avoids inadvertently trigger alternation of deployment and retraction when the vehicle is traveling at a speed close to the initial threshold and passes permanently on one side and the other of this threshold.

The deployment trigger (eg 50km / h) is chosen to be high enough for deployment to have a noticeable effect on aerodynamic drag. The drag varies with the square of the speed. For low speeds, the drag itself is very low. Deploying the baffle is not helpful.

The triggering threshold of the retraction (for example 40 km / h) is chosen so as to be sufficiently high so that the driver can reasonably consider the crossing of obstacles (sidewalks, speed bumps, etc.) at the speed considered. . Thus, it is avoided that the motor vehicle is brought to cross such an obstacle (likely to damage the deflector) while the deflector is deployed.

According to yet another variant, the control unit 24 also receives geolocation data associated with information on the driving situation.

For example, the control unit 24 may be configured to inhibit any deployment of the deflecting wall 15 in agglomeration where the speed is limited. Indeed, it is in agglomeration that there is the most risk of having to cross obstacles that may damage the deflecting wall 15.

Figures 3A and 3B show perspective diagrams of the aerodynamic deflector device 7 according to a second embodiment. This aerodynamic deflector device 7 is for example mounted in a housing provided for this purpose upstream of the wheel 3.

According to this embodiment, the deflecting wall 15 also has in the direction of the air flow striking said deflecting wall 15 in longitudinal section a shape of an arc of a circle and a straight form in cross section.

According to a variant not shown, the deflecting wall 15 may also have a divergent shape in cross section in the direction of the air flow striking said wall, in particular a curved shape.

In order to impart greater mechanical rigidity to the aerodynamic deflector device 7, the support 11 comprises a frame 25 of rectangular shape configured to be fixed to the chassis of a motor vehicle, from below, in particular by screwing.

In addition, the baffle wall 15 is pivotally connected to the frame 25 by side walls 27 forming a circular sector.

As best seen in FIG. 3B, the lateral walls 27 are connected by a closure wall 28 preventing dirt from reaching the actuator 19. The deflecting wall 15 with the side walls 27 and the closure wall then define a body only. open on one side and having a general shape of a shovel. The actuator 19 of this embodiment comprises a rotary output member 21 in direct contact with the deflecting wall 15. For this purpose, the rotary output member 21 comprises a wheel 29 provided on its periphery with an elastomer in contact rubbing with the baffle wall 15 for driving thereof between the retracted position (Figure 3A) and deployed (Figure 3B).

Figure 4 shows an exploded perspective diagram of a third embodiment.

This embodiment is very close to that of FIGS. 3A and 3B and differs in particular by the drive of the actuator 19.

Indeed, a curved rack 23 is fixed against the deflecting wall 15 (see arrow 31) and the rotary output member 21 of the actuator is in the form of a pinion meshing with the rack.

FIGS. 5A, 5B and 5C show different positions of the deflecting wall 15, namely a retracted position (FIG. 5A), an intermediate position (FIG. 5B) and an extended position (FIG. 5C).

Many other embodiments or examples are conceivable without departing from the scope of the present invention.

Thus, it can be expected that the extent of deployment is adjustable by the drive of the actuator 19 and under certain driving conditions, the baffle wall is only half-deployed as shown in Figure 5B.

It is thus clear that the aerodynamic deflector device 7 according to the invention makes it possible to improve the aerodynamic drag of the vehicle and therefore in particular the fuel consumption of the vehicle while allowing by its controlled or active character the crossing of obstacles at low speed. all security.

Claims (13)

Aerodynamic deflector device (7) for a motor vehicle wheel, comprising: a deflecting wall (15) movably mounted on a support (11) between on the one hand a retracted position, in which, in the mounted state, said wall; deflector (15) is raised relative to the support (11), and on the other hand an extended position, in which, in the mounted state, said deflecting wall (15) is lowered relative to the support (11), and - an actuator (19) connected to said baffle wall (15) and configured to move said baffle wall (15) between the retracted and deployed positions. 2. Device according to claim 1, characterized in that the deflecting wall (15) has in longitudinal section a circular arc shape. 3. Device according to claim 2, characterized in that the radius of the arc corresponds substantially to the radius of the wheel well (5) of the vehicle. 4. Device according to any one of claims 1 to 3, characterized in that the baffle wall (15) has in cross section a divergent shape in the direction of the air flow (10) striking said wall (15). 5. Device according to claim 4, characterized in that the deflecting wall (15) has a convex shape in cross section. 6. Device according to any one of claims 1 to 3, characterized in that the baffle wall (15) has a straight cross-section in the direction of the air flow (10) striking said wall. 7. Device according to any one of claims 1 to 6, characterized in that the carrier (11) is configured to be mounted in the wheel well (5) of a motor vehicle. 8. Device according to claim 7, characterized in that the carrier (11) comprises slides (13) configured to be fixed in the wheel well (7). 9. Device according to claims 2 or 3 taken together with claim 6, characterized in that the support (11) is formed as a frame (25) of rectangular shape configured to be fixed to the frame of a motor vehicle and in the deflecting wall (15) is pivotally connected to the frame (25) by side walls (27) forming a circle sector. 10. Device according to any one of claims 1 to 9, characterized in that the actuator (19) comprises a rotary output member (21) in direct or indirect engagement with the baffle wall (15). 11. Device according to claim 10, characterized in that it further comprises a rack (23) fixed to the baffle wall (15) and in that the output member (21) comprises a pinion meshing with the rack ( 23). 12. Device according to claim 10, characterized in that the output member (21) comprises a wheel (29) provided on its periphery with an elastomer in contact with the deflecting wall (15) for the training of the latter. this. 13. Motor vehicle, characterized in that it comprises at least one aerodynamic deflector device (7) according to any one of claims 1 to 12 disposed upstream of a vehicle wheel.