WO2018100271A1

WO2018100271A1 - Drag variation system and motor vehicle comprising such a system

Info

Publication number: WO2018100271A1
Application number: PCT/FR2017/053219
Authority: WO
Inventors: Franck Leterrier
Original assignee: Compagnie Plastic Omnium
Priority date: 2016-12-02
Filing date: 2017-11-23
Publication date: 2018-06-07
Also published as: FR3059628A1

Abstract

The invention relates to a drag variation system (1) for a motor vehicle, comprising an extendible device (3) provided with passive aerodynamic means (13) using the air flow on the drag variation system (1) in order to activate the extendible device (3).

Description

A drag variation system and a motor vehicle comprising such a system

The invention relates to a drag variation system for a motor vehicle.

It is already known to form active rear fins according to the speed of the motor vehicle in order to change the deportance especially above 90 km. h ^-1. These fins, usually formed of a rigid blade, are moved using at least one electric motor to give an impact capable of generating maximum grip and traction to the vehicle.

However, these fins are very heavy in particular because of the electromechanical actuators piloted and deployment mechanisms compared to a fixed wing which increases the cost and mass of the motor vehicle on which it is mounted.

The object of the invention is to overcome these drawbacks by providing a drag variation system for a passive type of motor vehicle that makes it possible to limit its impact on the mass of the vehicle.

To this end, the invention relates to a drag variation system for a motor vehicle comprising an extensible device and a fastening device arranged to fasten said system to a motor vehicle, characterized in that the extensible device comprises aerodynamic means. passive using the airflow on the drag variation system to activate the expandable device.

Advantageously according to the invention, the system is of the passive type, that is to say it uses the movement of the vehicle including the natural flow of air around the vehicle to deploy. Thus, the implantation is easier both from the point of view of the volume required and the mass added in particular with respect to active systems such as, for example, a movable wing mentioned above. The system operates autonomously for the user of the vehicle, that is to say it has no manipulation to perform.

According to other optional features of embodiment of the invention:

the fixing device comprises a frame supporting the extensible device;

the extensible device comprises at least one envelope extensible with respect to the fixing device and displaced by the passive aerodynamic means;

the extensible device comprises a plurality of envelopes extensible in a telescopic manner;

the passive aerodynamic means comprise at least one elastic membrane collecting said flow of air so as to selectively vary its volume in order to actuate the extensible device;

the volume of said at least one elastic membrane increases with the increase of the flow of air to actuate the extensible device; said at least one elastic membrane is formed of elastomer;

- The system further comprises a passive return device of the extensible device allowing in the absence of air flow on the drag variation system to fold the extensible device;

the passive return device comprises a spring mounted between the extensible device and the fixing device in order to fold the extensible device in the absence of air flow on the drag variation system.

Finally, the invention relates to a motor vehicle characterized in that it comprises at least one drag variation system as presented above. Preferably, said at least one system is attached to the flag or tailgate of said motor vehicle.

Embodiments of the invention given by way of nonlimiting examples and with reference to the appended figures in which:

FIG. 1 is a perspective representation of a first embodiment of a drag variation system according to the invention;

- Figure 2 is a sectional representation along the plane ll-ll of Figure 1;

- Figure 3 is a perspective representation of a second embodiment of a drag variation system according to the invention in the deployed position;

- Figure 4A is a representation in section along the plane IV-IV of Figure 3;

- Figure 4B is a sectional representation similar to Figure 4A, the drag variation system according to the invention being in the retracted position;

- Figure 5A is a sectional representation along the plane V-V of Figure 3;

- Figure 5B is a sectional representation similar to Figure 5A, the drag variation system according to the invention being in the retracted position;

FIG. 6 is a partial representation of a first variant of the drag variation system according to the invention;

FIG. 7 is a partial representation of a second variant of the drag variation system according to the invention.

In the different figures, identical or similar elements bear the same references. The description of their structure and function is therefore not systematically repeated.

As illustrated in FIGS. 1 and 2, the invention, according to a first embodiment, relates to a drag variation system 1 for a motor vehicle 2, that is to say a system intended to reduce the resistance of the vehicle. the air when moving the motor vehicle to gain speed and / or to save energy.

Preferably, the system 1 forms an air deflector implanted at the level of the flag or the tailgate of the motor vehicle. This air deflector can be a spoiler on the roof, a spoiler on tailgate or a tailgate side baffle, integrated into the side uprights located on each side of the bezel.

In the example of the first embodiment, the drag variation system 1 is intended to be mounted on the upper rear part of a roof 4 of a motor vehicle 2. As best seen in FIG. 2, the system 1 is integrated. to form a spoiler 9 at the flag 4 or the tailgate 12 of the vehicle 2.

The system 1 comprises an extensible device 3 deployed, preferably, from a predetermined speed of the vehicle on which it is integrated. Preferably, the extensible device 3 comprises a frame 5 and an expandable envelope 7 intended to lengthen back the surface of the spoiler 9 of the vehicle 2 along which the air flows. It is understood that the envelope 7 deployed reduces the drag of the vehicle 2. The term envelope describes a hollow rigid piece to limit the overall mass of the system 1 but also to receive at least a portion of the passive means 13 aerodynamic. For these same considerations, the chassis 5 and the expandable envelope 7 can be made from a plastic material preferentially obtained by an injection molding process.

The drag variation system 1 further comprises a fixing device 10 arranged to integrate the spoiler 9 on a motor vehicle. Preferably, the fixing device 10 comprises a frame 11 supporting the extensible device 3. The frame 11 thus ensures a fixed interface between the extensible device 3 and the roof 4 or the tailgate 12 of the vehicle 2.

As shown in Figure 1, the frame 11 has two grooves 15 for guiding a portion of the flow of air to the passive means 13 aerodynamic. More specifically, the grooves 15 open towards a channel 17 facing the extensible device 3 and more particularly to the frame 5. Finally, it should be noted that the channel 17 can be opened, or not, towards the telescope 6 so as to form an exhaust at air flow deflected by the grooves 15. Of course, the number of grooves 15 can change depending on the passive aerodynamic means 13 used. For example, a single groove 15 could cover most of the width of the spoiler 9 or a number greater than two could be provided to match that of the passive means 13 aerodynamic.

Preferably, the extensible device 3 is arranged to be deployed from a predetermined speed corresponding to a significant drag and overconsumption for the vehicle 2. For example, the extensible device 3 could be arranged to start deploying at 50 km. h ^"1 to be fully deployed in direction A only from 90 km h ^{" 1} . Advantageously according to the invention, the extensible device 3 comprises passive aerodynamic means 13 using the flow of air along the drag variation system 1 to actuate the extensible device 3. Thus, the system 1 is of the passive type, that is to say it uses the speed of movement of the vehicle 2 and, more specifically, the flow of air along the flag 4 or the tailgate 12 induced by the movement of the vehicle 2, to selectively deploy or retract. It is therefore understood that no energy on board or produced by the motor vehicle 2 is necessary to activate the extensible device 3. In addition, the implantation is easier both from the point of view of the volume required and the mass added in particular compared to controlled electromechanical systems.

As illustrated in FIG. 2, the passive aerodynamic means 13 comprise at least one deformable or elastic membrane 19, preferentially made of elastomer, collecting the flow of air that arrives from the channel 17 in order to vary its volume and that its wall exerts and a thrust against the inner walls of the casing 7 to move it towards the rear of the motor vehicle 2. In the example of Figure 2, a diaphragm 19 is shown with a maximum variation of its volume corresponding to the maximum displacement between the frame 5 and the casing 7. The same membrane referenced 19 'has also been shown at rest for better understanding.

In addition, in order to promote the most laminar flow of air possible but also improve the aesthetics of the drag variation system 1, it is visible in FIGS. 1 and 2 that a deflector 21, possibly shaped, by example by molding, with the frame 5, is positioned at the interface between the frame 5 and the casing 7.

Preferably, the system 1 further comprises a device 23 for passive return of the extensible device 3. Indeed, it is preferentially desired that in the absence of sufficient air flow, that is to say below the predetermined speed of the vehicle 2, or that the vehicle stops 2 , the extensible device 3 is fully returned to the rest position, that is to say that the envelope 7 retracts to the maximum in the frame 5.

As can be seen in FIG. 2, the passive return device 23 comprises, for example, at least one coil-type spring 25 mounted between the frame 5 and the end of the casing 7 in order to fold the extensible device 3 into the no airflow on the drag variation system 1. The stiffness of the spring 25 must be selectively selected to allow the deployment of the envelope 7 but will also allow its entry during the deceleration phase and then stop the vehicle 2.

Finally, the frame 5 may also include a pivoting hatch 27 allowing the entry of air into the membrane 19 from a predetermined flow rate and / or retaining the air present to limit the moment when the envelope 7 can move.

A second embodiment of a system 1 according to the invention is presented in FIGS. 3 to 5B. This second embodiment differs essentially from the first embodiment in that the extensible device 3 comprises several envelopes 7 _X preferably extendable telescopically.

As shown in Figure 3, the extensible device 3 comprises a frame 5 and two envelopes 7ι, Ί2 extensible for extending backward the surface of the spoiler 9 of the vehicle 2 along which the air flows. It is understood that the envelopes 7ι, Ί2 deployed reduce the drag of the vehicle 2.

In addition, it can be seen in FIGS. 3 to 5B that a deflector 211, 2I2, possibly integral with the frame 5 and the casing 72 respectively, is positioned at each interface between the frame 5 and the casing 72 respectively. between the envelopes 7i and 72 in order to promote the most laminar flow of air possible but also improve the aesthetics of the drag variation system 1.

According to the second embodiment of the invention, the passive aerodynamic means 13 comprise at least one deformable or elastic membrane 19, preferably made of elastomer, collecting the flow of air that arrives from the channel 17 in order to vary its volume and its wall thus exerts a thrust against the inner walls of the two envelopes 7i, 72. to move them towards the rear of the motor vehicle 2. Comparing FIGS. 4A-5A and 4B-5B representing the device 3 extensible respectively in its position deployed and retracted, it is better to see the variation of the volume of the membrane 19 between Figure 4A representing its maximum variation and, Figure 4B, its minimum variation.

As for the first embodiment, the system 1 of the second embodiment may further comprise a device 23 for passive return of the extensible device 3 comprising, for example, at least one coil-type spring 25 mounted between the frame 5 and the end of the envelope 7i to fold the extensible device 3 in the absence of air flow on the drag variation system 1, that is to say go from Figures 5A to Figure 5B.

The stiffness of said at least one spring 25 must be selectively selected to allow the deployment of the envelopes 7i, 72 but will also allow their retraction during the deceleration and stopping phase of the vehicle 2. For example, springs 25 with different stiffnesses could be respectively attached to the envelopes 7i, 72 to program a predetermined deployment of the envelopes 7i, 72. For example, the extensible device 3 could be arranged to begin to deploy, 50 km. h ^"1 , the envelope 72 to be fully deployed only from 70 km h ^{" 1} . At this same last speed, the extensible device 3 could begin to deploy the envelope 7i to be fully deployed only from 90 km. h ^"1.

Finally, the frame 5 may also include a pivoting hatch 27 allowing the entry of air into the membrane 19 from a predetermined flow rate and / or retaining the air present to limit the moment when the envelopes 7ι, Ί2 can move.

The invention is not limited to the embodiments presented and other embodiments will become apparent to those skilled in the art. It is possible in particular that several drag variation systems 1 are attached to the same vehicle 2 or that the system 1 is not mounted on the roof 4 but, alternatively, on the tailgate 6 or another part of the vehicle body 2.

The geometry of the system 1 can not be limited to those presented in FIGS. 1 to 5B. It is particularly immediate that the extensible devices 3 presented below use a kinematics whose direction is substantially parallel to the flag 4. However, the kinematics and / or the shape of the envelopes 7, 7 _X could be modified to increase the deportation of the vehicle by providing a direction of oblique deployment relative to the upper surface of the roof 4.

As illustrated in FIG. 6, it is also possible for several membranes 19i, 192, 193, 19 ₄ , 19o to be used. The number of envelopes will be calculated according to the effort required for the deployment of the envelopes 7, 7 _X but will also eventually have to overcome the stiffness of the springs 25.

Finally, the membrane 19 is shown in Figures 2 and 4A according to its maximum volume for which the membrane 19 is pressed against the frame 5 and the casing 7, 7 _X. Indeed, this configuration avoids from a certain air flow no longer able to further inflate the membrane 19 to prevent tearing.

As seen in Figure 7, alternatively, at least one hole 20 in the membrane 19 could be provided to create a leakage flow B able to cap the maximum volume achievable by the membrane 19 to prevent tearing.

Claims

1. System (1) for variation of drag for a motor vehicle comprising an extensible device (3) and a fastening device (10) arranged to secure said system to an automobile vehicle (2), characterized in that the extensible device (3) comprises passive aerodynamic means (13) using the air flow on the drag variation system (1) to activate the extensible device (3).

2. System (1) according to the preceding claim, wherein the device (10) for fixing comprises a frame (11) supporting the device (3) extensible.

3. System (1) according to any one of the preceding claims, wherein the extensible device (3) comprises at least one envelope (7, 7ι, I2) expandable relative to the fixing device (10) and moved by the means (13) passive aerodynamics.

4. System (1) according to the preceding claim, wherein the extensible device (3) comprises a plurality of envelopes (7, 7ι, I2) extendable telescopically.

5. System (1) according to any one of the preceding claims, wherein the passive aerodynamic means (13) comprise at least one elastic membrane (19) collecting said flow of air so as to selectively vary its volume to actuate the air. extensible device (3).

6. System (1) according to the preceding claim, wherein the volume of said at least one elastic membrane (19) increases with the increase in the flow of air to actuate the device (3) extensible.

7. System (1) according to claim 5 or 6, wherein said at least one membrane (19) elastic is formed of elastomer.

8. System (1) according to any one of the preceding claims, wherein the system (1) further comprises a device (23) passive return of the device (3) expandable in the absence of air flow on the drag variation system (1) to fold the extensible device (3).

9. System (1) according to the preceding claim, wherein the device (23) passive return comprises a spring (25) mounted between the device (3) extensible and the device (10) for fixing to fold the device (3). ) expandable in the absence of airflow on the drag variation system (1).

10. Motor vehicle (2) characterized in that it comprises at least one drag variation system (1) according to one of the preceding claims.

11. Motor vehicle (2) according to the preceding claim, wherein said at least one system (1) is attached to the roof (4) or the tailgate (6) of said vehicle automobile.