vehicle equipped with optimized steering of two deflectors placed in front of the front wheels

Abstract

The invention relates to a vehicle comprising two front wheels (12, 13) and two rigid deflectors (1, 2) placed in front of the two front wheels (12, 13) each being mounted in rotation between an active position for which it projects under the vehicle in front of a front wheel (12, 13) extending in a vertical and transverse plane YZ of the vehicle, an inactive position for which it is stored in the vehicle. The vehicle comprises a braking system (10) comprising a brake booster (18) and a brake pedal (11).According to the invention, the vehicle comprises a mechanism for actuating the two deflectors (1, 2) based on an actuating circuit (51) originating on the brake booster (18) and opening onto an actuator (52) which is connected to the two deflectors (1, 2), pressure on the brake pedal (11) causing both a braking phase of the vehicle and an activation of the actuator (52) causing a pivoting of the two deflectors (1, 2) until reaching the inactive position. . Figure for the abstract: Figure 4.

Description

Title of the invention: vehicle equipped with optimized steering of two deflectors placed in front of the front wheels

[0001] The present invention relates to a vehicle with optimized steering of two deflectors placed in front of front wheels. We assume that a vehicle according to the invention conventionally comprises front wheels and rear wheels.

[0002] In order to better understand the positioning of the various parts involved in a vehicle according to the invention, the description is carried out with reference to a direct orthonormal reference frame XYZ in which X is a front-rear longitudinal axis of the vehicle oriented towards the rear, Y is a transverse axis oriented towards the right of the vehicle and Z is a vertical axis directed upwards.

[0003] Currently, some motor vehicles are equipped with two deflectors, each placed in front of a front wheel, each of said deflectors being in the form of a rigid and thin flap extending in a transverse and vertical plane YZ of the vehicle. These flaps, generally fixed to a front bumper diffuser, are intended to deflect the air located in front of the vehicle during a rolling phase of the latter, so that this air does not directly impact the front wheels. In this way, these deflectors improve the aerodynamics of the vehicle with the consequence of: - a reduction in the fuel consumption of said vehicle, - a reduction in the emission of CO2 particles, - an increase in the autonomy of the vehicle.

[0004] It was observed that these deflectors have little influence when the vehicle is traveling at a speed less than or equal to 70 km / h, but play a determining role in fuel consumption when said vehicle is traveling at speeds greater than 70 km / h. To meet this targeted need for implementing the deflectors, it was envisaged to be able to control these deflectors in rotation, between an active deployed position and an inactive stowed position. To do this, each deflector is mounted in rotation about a transverse and horizontal rotation axis Y of the vehicle, and can thus pivot about said axis, from the active position for which it projects under the vehicle by extending in a transverse and vertical plane YZ of the vehicle, to the inactive position for which it extends in a horizontal plane by being folded against a horizontal wall of the vehicle.These deflectors are automatically controlled according to a threshold speed of the vehicle, by means of a central computing unit which is embedded in the vehicle. When the input data of this central unit indicates that the deflectors must be placed in one of the two previous positions, said central unit activates an electric motor which is associated with the deflector and which . causes the movement of said deflector to place it in the desired position.

[0005] However, it turns out that controlling these deflectors based solely on the speed of the vehicle to be positioned relative to a threshold speed is not sufficiently precise, and that ultimately, these deflectors play a major role regardless of the speed of the vehicle and that their influence is negligible during vehicle braking phases.

[0006] A vehicle according to the invention is provided with a mechanism for controlling the two flaps allowing said two flaps to be systematically placed in the active position during driving phases of said vehicle, and in the inactive position during braking phases thereof.

[0007] The subject of the invention is a vehicle comprising two front wheels, a front bumper diffuser and two rigid deflectors placed in front of the two front wheels, each being rotatably mounted on the bumper diffuser between an active position in which it projects under the vehicle in front of a front wheel, extending in a vertical and transverse plane YZ of the vehicle, and an inactive position in which it extends horizontally, being stored against the diffuser, said vehicle comprising a braking system comprising a brake booster, a braking circuit including brake fluid, and a brake pedal.

[0008] According to the invention, the vehicle comprises a mechanism for actuating the two deflectors based on an actuating circuit in which the brake fluid circulates and on an actuator, said actuating circuit originating on the brake booster and opening onto the actuator which is connected to the two deflectors, and, during a rolling phase of the vehicle, the deflectors are automatically placed in the active position, pressure on the brake pedal causing both a braking phase of the vehicle and an activation of the actuator causing a pivoting of the two deflectors to the inactive position.The specificity of a vehicle according to the invention is that during a rolling phase of the vehicle, the deflectors are systematically in the active position for which they deflect the air placed in front of the vehicle to the sides of the latter in order in particular to improve its aerodynamics, and during a braking phase they are automatically stored in the inactive position for which they have no action on the air placed in front of the vehicle. In this way, at each braking phase, since the aerodynamics of the vehicle no longer has to be optimized, the deflectors are stored automatically. It should be remembered that the axis of rotation of each of the two reflectors extends along a transverse axis Y of the vehicle.In a vehicle according to the invention, pressure on the brake pedal causes the brake fluid to move, both in the braking circuit and the circuit for actuating the two deflectors, reflecting the fact that at each braking phase the deflectors retract.

[0009] According to a possible characteristic of the invention, the two deflectors are mounted on the same cylindrical actuating rod extending along a transverse axis Y of the vehicle while being fixed on said actuating rod, the actuator when activated by pressure on the brake pedal, causing a rotation of this actuating rod around its axis of revolution to place the two deflectors in the active position. In this way, the actuator is configured to cause a rotation of a given angular amplitude, of the actuating rod joining the two deflectors. The use of a single actuating rod for the two deflectors makes it possible to simplify the actuating mechanism of said deflectors, and to limit the sources of failure by limiting the number of parts involved in the actuating mechanism of said deflectors.

[0010] According to a possible characteristic of the invention, the two deflectors are placed at the two ends of the actuating rod considered along a longitudinal axis of said actuating rod, the actuator acting on a central zone of this actuating rod. Thanks to such a configuration, the actuating mechanism of the two deflectors is balanced, limiting the risk of drift over time of better operation of one of the deflectors to the detriment of the other. Advantageously, the length of the actuating rod joining the central zone to each deflector is constant.

[0011] According to a possible characteristic of the invention, the actuator is a single-acting cylinder having a body receiving the brake fluid, and a sliding rod which is housed in said body, a free end of the sliding rod being connected to a secondary axis which is fixed to the actuating rod while being perpendicular thereto, so that a translational movement of the sliding rod in the body generated by pressure exerted on the brake pedal, causes a movement of the secondary axis which then causes a rotation of the actuating rod around its axis of revolution. For this configuration, a translational movement of the sliding rod in the body of the cylinder causes a rotational movement of the secondary axis around the actuating rod, causing a rotation of said actuating rod around its axis of revolution.Pressure exerted on the brake pedal will first cause the brake fluid to move in the actuation circuit and then in the body of the single-acting cylinder, moving the sliding rod in translation in the body to cause the actuation rod to rotate in a direction which will encourage the deflectors to move towards the inactive position.

[0012] According to a possible characteristic of the invention, the free end of the sliding rod is mounted articulated on the secondary axis.

[0013] According to a possible characteristic of the invention, the actuation circuit comprises a flow limiter placed between the brake booster and the actuator, the flow limiter allowing a delay to be introduced between the moment the brake pedal is released and the moment the deflectors return to the active position. Schematically, the principle of such a limiter is to have a forward and a return brake fluid pipe, so that the cross-section of the return pipe is less than that of the forward pipe. The cross-section of the forward pipe is dimensioned in such a way that it does not induce any influence on the flow of brake fluid traveling towards the cylinder. In this way, after the driver has exerted pressure on the brake pedal to brake the vehicle and place the deflectors in the inactive position, when he releases the pressure on said brake pedal, said deflectors will not instantly return to the active position. The flow limiter will in fact delay the repositioning of these deflectors in the active position.Thus, for example, in the particular case where the vehicle must be braked temporarily when arriving in front of a speed bump, if the driver wishes to cross this speed bump he will release the brake pedal without the deflectors having instantly repositioned themselves in the active position thanks to the presence of the flow limiter. The vehicle will then cross this speed bump while the deflectors are in the inactive position and therefore without risk of damaging these deflectors.

[0014] According to a possible characteristic of the invention, the flow limiter is associated with a mechanical retarder which has been previously dimensioned to allow repositioning of the deflectors in the active position after a given period, after releasing the brake pedal.

[0015] According to a possible characteristic of the invention, a thermostatic valve is fixed to the brake booster, the actuation circuit originating on this thermostatic valve, said electrostatic valve preventing any return of brake fluid to the brake booster if the temperature of said brake fluid has reached a threshold value, keeping the deflectors in the inactive position.

[0016] According to a possible characteristic of the invention, each deflector is flat and has a rectangular shape, said deflector passing from the active position to the inactive position and vice versa by means of a 90° rotation. These deflectors are similar to light and thin shutters which can move easily, without requiring too much actuation energy.

[0017] Another subject of the invention is a method of actuating the two deflectors of a vehicle according to the invention, when said two deflectors are in an active position.

[0018] According to the invention, the method comprises the following steps: - a step of pressure on the brake pedal for a fairly long time, causing both a braking phase of the vehicle and a phase of rotation of the deflectors until each reaches the inactive position, - a step of releasing the brake pedal causing the deflectors to rotate in the opposite direction until reaching the active position.

[0019] The principle of such a method is that each time the brake pedal is pressed for a sufficiently long time, the flaps automatically move to the inactive position, and each time the brake pedal is released, the flaps return to their active position. There is no intermediate position between the active position and the inactive position. The term "sufficiently long time" means "time greater than a predefined threshold value".

[0020] A vehicle according to the invention has the advantage of having deflectors placed in front of the front wheels, the position of which is adjustable solely as a function of the position of the brake pedal: In this way, the brake pedal has a double action: -ensure a braking phase of the vehicle, -cause the deflectors to be stored in the inactive position.

[0021] It follows that the deflectors are deployed in the active position only when needed, i.e. during all phases of vehicle travel not involving any braking phase. A vehicle according to the invention also has the advantage of comprising an actuation mechanism for the two deflectors which is judiciously designed in the vehicle, based on a braking circuit already existing in the vehicle. In this way, the actuation mechanism of these deflectors did not have to be completely reinvented.

[0022] A detailed description of a preferred embodiment of a vehicle according to the invention is given below, with reference to the following figures:

[0023] [Fig-1] [Fig.l] is a schematic perspective view of a vehicle according to the invention showing the location of the deflectors,

[0024] [Fig.2] [Fig.2] is a schematic perspective view of a braking system of a state-of-the-art vehicle,

[0025] [Fig.3] [Fig.3] is a schematic perspective view of a braking system and of a mechanism for actuating the two deflectors of a vehicle according to the invention, the two deflectors being in the active position,

[0026] [Fig.4] [Fig.4] is the schematic view of [Fig.3], the two deflectors being in the inactive position.

[0027] Referring to [Fig.l], some motor vehicles are equipped with two deflectors 1, 2 each placed in front of a front wheel 3, each of said deflectors 1, 2 being in the form of a rigid and thin flap, generally having a rectangular outline. These deflectors 1, 2 extend in a transverse and vertical plane YZ of the vehicle. These deflectors 1, 2 which are generally fixed to a front bumper diffuser 4, have the purpose of deflecting the air located in front of the vehicle during a rolling phase thereof, so that this air does not directly impact the front wheels 3 placed just behind said deflectors 1, 2. In this way, these deflectors 1, 2 improve the aerodynamics of the vehicle with the following main consequences: - a reduction in the fuel consumption of said vehicle, - a reduction in the emission of CO2 particles, - an increase in the autonomy of the vehicle.

[0028] However, it has been observed that these deflectors 1, 2 were not always useful, whatever the phases of use of the vehicle. For this reason, one solution consisted of mounting each of said two deflectors 1, 2 in rotation around an axis of rotation integral with the shield diffuser 4, and extending along a transverse axis Y of the vehicle. In this way, each deflector 1, 2 is mounted in rotation on said diffuser 4, between an active position for which it extends under the vehicle in a vertical and transverse plane YZ of said vehicle and an inactive position for which it is stored against a wall of the shield diffuser 4 while extending in a horizontal plane. In this way, each deflector 1, 2 passes from one to the other of the positions by means of a rotation of 90°.Software from a central computing unit on board the vehicle then controls the movement of these deflectors 1, 2 between the active position and the inactive position, according to the needs encountered, linked to the different phases of use of the vehicle and in particular to its speed.

[0029] Following this first observation allowing the conclusion that the deflectors 1, 2 were not always useful whatever the phase of use of the vehicle, it was found that these deflectors 1, 2 were simply not useful during the braking phases of the vehicle. Rather than reprogramming the software of the central computing unit so that it places the two deflectors 1, 2 in the inactive position at each braking phase of the vehicle, the present invention consists of indexing the actuation mechanism of the two deflectors 1, 2 directly on the braking system 10 of the vehicle. In this way, pressure exerted on a brake pedal 11 of a vehicle according to the invention will have a double action: -cause a braking phase of the vehicle, -move deflectors 1, 2 until they reach the inactive position.

[0030] Referring to [Fig. 2], a vehicle generally comprises two front wheels 12, 13 and two rear wheels 14, 15, as well as a braking system 10, comprising the brake pedal 11, and a brake booster 18. The braking system 10 also comprises a front circuit 16 for circulating a brake fluid and a rear circuit 17 for circulating a brake fluid, the brake fluid being the same in said front circuit 16 and said rear circuit 17. Schematically, the front circuit 16 for circulating the brake fluid comprises a component connecting the brake booster 18 to a braking element 19 acting on a front wheel 12, 13 and another component connecting the brake booster 18 to a braking element 20 acting on the other front wheel 12, 13. These two braking elements 19, 20 may for example be constituted by brake discs. Similarly and schematically, the rear circuit 17 for circulating the brake fluid comprises a component connecting the brake booster 18 to a braking element 21 acting on a rear wheel 14, 15 and another component connecting the brake booster 18 to a braking element 22 acting on the other rear wheel 14, 15. These two braking elements may for example be constituted by shoes. Pressure on the brake pedal 11 which interacts with the brake booster 18 causes the brake fluid to move in the front circuit 16 and in the rear circuit 17, causing the various braking elements 19, 20, 21, 22 to be activated, which tightly grip the various wheels 12, 13, 14, 15 to ensure braking of the vehicle.Releasing the brake pedal 11 instantly stops the vehicle from braking and it can then move without restriction.

[0031] In the context of the present invention, the brake system which is already well known on existing vehicles is described in summary form, without going into operational details.

[0032] Referring to Figures 3 and 4, the actuating mechanism 50 of the deflectors 1, 2 of a vehicle according to the invention is directly grafted onto the braking system 10 of said vehicle. This actuating mechanism 50 comprises an actuating circuit 51, and an actuator 52 placed upstream of the two deflectors 1, 2.

[0033] For a vehicle according to the invention, the two deflectors 1, 2 are fixed to an actuating rod 53 extending along a transverse axis Y of the vehicle. This actuating rod 53 is cylindrical and elongated, and the two deflectors 1, 3 are fixed to the two ends of this actuating rod 53 considered along a longitudinal axis of said actuating rod 53, without projecting beyond the actuating rod. A secondary axis 54 in the form of a rectilinear cylindrical rod is fixed in the middle of the actuating rod 53 so as to extend perpendicularly thereto. There is no possibility of movement between the two deflectors 1, 2 and the actuating rod 53 and between the secondary axis 54 and said actuating rod 53. It should be noted that the actuating rod 53 is rectilinear.

[0034] The actuation circuit 51 originates on the brake booster 18 and opens into the actuator 52. This actuation circuit 51 is crossed by brake fluid and the actuator 52 is constituted by a single-acting cylinder. This single-acting cylinder 52 comprises a hollow and cylindrical body 55 in which is placed a sliding rod 56 preferably of cylindrical shape. The body 55 is delimited by a cylindrical side wall 55 and by a flat bottom 57 of circular shape. The sliding rod 56 is mounted in the hollow body 55 by means of a prestressed return element 59, such as for example a spiral spring, having a tendency by default to push back said sliding rod 56, from the bottom 57 of the body 55. The length of the sliding rod 56 is greater than that of the body 55, so that said sliding rod 56 emerges from said body 55 when it is in contact with the bottom 57 of said body 55. The sliding rod 56 thus has a first end which is located opposite the bottom 57 of the body 55, and a second end which emerges from said body 55 and which is mounted articulated on the secondary axis 54 which is fixed to the actuating rod 53. The first end and the second end mentioned above are to be considered relative to a longitudinal axis of the sliding rod 56.

[0035] Referring to [Fig. 3], when the vehicle is in the rolling phase and no foot pressure is exerted on the brake pedal 11, the deflectors 1, 2 are in the active position for which they extend in a transverse and vertical plane YZ of the vehicle. They can thus deflect the air located at the front of the vehicle and thus improve its aerodynamics.

[0036] Referring to [Fig.4], when the driver exerts pressure on the brake pedal 11 while the vehicle is in the rolling phase, two simultaneous actions are generated: - a conventional braking phase of the vehicle for which each brake element 19, 20, 21, 22 exerts pressure on the wheel concerned 12, 13, 14, 15, - rotation of the deflectors 1, 2 which thus pass from the active position to the inactive position for which they are stored along the vehicle and no longer perform any air deflection function.

[0037] The method of switching the deflectors 1, 2 from the active position to the inactive position follows the following steps: - a pressure step with the foot on the brake pedal 11 which will cause a movement of the brake fluid circulating in the actuation circuit 51, - a step of inflow of brake fluid into the body 55 of the single-acting cylinder 52, - a step of displacement of the sliding rod 56 towards the bottom 57 of the body 55 under the effect of the inflow of brake fluid into said body, said displacement being carried out by overcoming the force produced by default by the prestressed return element 59 which naturally tends to push the sliding rod 56 away from the bottom 57, - a step of rotating the secondary axis 54 which is fixed in an articulated manner to the sliding rod 56, this rotation taking place around the actuating rod 53 which then pivots around its axis of revolution, - a step of simultaneous pivoting of the two deflectors 1, 2 which then reach the inactive position.

[0038] As long as the brake pedal 11 remains depressed, the deflectors 1, 2 remain in the inactive position. Releasing the brake pedal 11 allows the two deflectors 1, 2 to instantly return to the active position, the steps of the method below before described being carried out in the opposite direction: a part of the brake fluid leaves the body 55 of the single-acting cylinder 52 allowing the prestressed element 59 to bring the sliding rod 56 back to the bottom of the body 55, this movement of the sliding rod 56 causing the secondary axis 54 to pivot in the opposite direction which causes the actuating rod 53 to pivot in the opposite direction around its axis of revolution.

[0039] The actuation circuit 51 is provided with a flow limiter 60 placed upstream of the actuator 52, between the brake booster 18 and said actuator 52, to delay an instantaneous repositioning of the two deflectors 1, 2 in the active position, when the driver releases the pressure on the brake pedal 11. Schematically, the principle of such a limiter 60 is to have a forward conduit and a return conduit for brake fluid, so that the cross-section of the return conduit is less than that of the forward conduit. The cross-section of the forward conduit is dimensioned in such a way that it does not induce any influence on the flow of brake fluid traveling towards the cylinder. Thus, for example, in the particular case where the vehicle must be braked temporarily when arriving in front of a speed bump.When the driver decides to cross this speed bump, he will release the brake pedal without the deflectors having instantly repositioned themselves in the active position thanks to the presence of the flow limiter. The vehicle will then be able to cross this speed bump while the deflectors are in the inactive position and therefore without risk of damaging these deflectors.

[0040] During a rolling phase of the vehicle, it may happen that the brake fluid heats up and reaches too high a temperature. A thermostatic valve 61 is then fixed to the brake booster 18 so that the actuation circuit 51 originates on this thermostatic valve 61, said electrostatic valve 61 preventing any return of the brake fluid to the brake booster 18 if the temperature of said brake fluid has reached a threshold value, keeping the deflectors 1, 2 in the inactive position.

Claims

Claims

1. Vehicle comprising two front wheels (12, 13), a front bumper diffuser (4) and two rigid deflectors (1, 2) placed in front of the two front wheels (12, 13) each being rotatably mounted on the bumper diffuser (4) between an active position for which it projects under the vehicle in front of a front wheel (12, 13) extending in a vertical and transverse plane YZ of the vehicle, to an inactive position for which it extends horizontally being stored against the diffuser (4), said vehicle comprising a braking system (10) comprising a brake booster (18), a braking circuit (16, 17) including brake fluid, and a brake pedal (11), characterized in that it comprises a mechanism for actuating the two deflectors (1, 2) based on an actuating circuit (51) in which the brake fluid circulates and on an actuator (52),said actuation circuit (51) originating on the brake booster (18) and opening onto the actuator (52) which is connected to the two deflectors (1, 2), and in that during a rolling phase of the vehicle the deflectors (1, 2) are automatically placed in the active position, pressure on the brake pedal (11) causing both a braking phase of the vehicle and an activation of the actuator (52) causing a pivoting of the two deflectors (1, 2) until reaching the inactive position.

2. Vehicle according to claim 1, characterized in that the two deflectors (1, 2) are mounted on the same cylindrical actuating rod (53) extending along a transverse axis Y of the vehicle while being fixed on said actuating rod (53), and in that the actuator (52) when activated by pressure on the brake pedal (11), causes this actuating rod (53) to rotate around its axis of revolution to place the two deflectors (1, 2) in the active position.

3. Vehicle according to claim 2, characterized in that the two deflectors (1, 2) are placed at the two ends of the actuating rod (53) considered along a longitudinal axis of said actuating rod (53), and in that the actuator (53) acts on a central zone of this actuating rod (53).

4. Vehicle according to any one of claims 2 or 3, characterized in that the actuator is a single-acting cylinder (52) having a body (55) receiving the brake fluid, and a sliding rod (56) which is housed in said body (55), and in that a free end of the sliding rod (56) is connected to a secondary axis (54) which is fixed to the actuating rod (53) while being perpendicular to the latter, so that a translational movement of the sliding rod (56) in the body (55) generated by pressure exerted on the brake pedal (11), causes a movement of the secondary axis (54) which then causes the actuating rod (53) to rotate around its axis of revolution.

5. Vehicle according to claim 4, characterized in that the free end of the sliding rod (56) is mounted articulated on the secondary axis (54).

6. Vehicle according to any one of claims 1 to 5, characterized in that the actuation circuit (51) comprises a flow limiter (60) placed between the brake booster (18) and the actuator (52), and in that the flow limiter (60) makes it possible to introduce a delay between the moment when the brake pedal (11) is released and the moment when the deflectors (1, 2) return to the active position.

7. Vehicle according to claim 6, characterized in that the flow limiter (60) is associated with a mechanical retarder which has been previously dimensioned to allow repositioning of the deflectors (1, 2) in the active position after a given period, after release of the brake pedal (11).

8. Vehicle according to any one of claims 1 to 7, characterized in that a thermostatic valve (61) is fixed to the brake booster (18), and in that the actuation circuit (51) originates on this thermostatic valve (61), said thermostatic valve (61) preventing any return of brake fluid to the brake booster (18) if the temperature of said brake fluid has reached a threshold value, keeping the deflectors (1, 2) in the inactive position.

9. Vehicle according to any one of claims 1 to 8, characterized in that each deflector (1,2) is flat and has a rectangular shape, and in that said deflector (1,2) passes from the active position to the inactive position and vice versa by means of a rotation of 90°.

10. Method for actuating the two deflectors (1, 2) of a vehicle according to any one of claims 1 to 9 when said two deflectors (1, 2) are in an active position, characterized in that it comprises the following steps: - a step of pressing the brake pedal (11) for a fairly long time, causing both a braking phase of the vehicle and a phase of rotating the deflectors (1, 2) until each reaches the inactive position, - a step of releasing the brake pedal (11) causing the deflectors (1, 2) to rotate in the opposite direction until the active position is reached.

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