Method for operating a rear spoiler and rear spoiler control unit

Abstract

Method for operating a rear spoiler (4) of a motor vehicle, which has a self-locking and / or mechanically braked adjustment kinematics (5), wherein, depending on at least one defined operating condition of the motor vehicle, an electric motor (8) acting on the rear spoiler (4) is controlled in order to displace the rear spoiler (4) between defined rear spoiler positions, characterized by the fact that on the basis of a signal provided by a position sensor (10) assigned to the rear spoiler (4), it is checked whether the aerodynamic force acting on the extended rear spoiler (4) while the motor vehicle is traveling is generally smaller or generally greater than a breakaway force and / or braking force or a breakaway torque and / or braking torque of the adjustment kinematics (5), when the aerodynamic force acting on the extended rear spoiler (4) while the motor vehicle is moving is generally greater than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics (5), the electric current is determined with which the electric motor (8) is controlled in order to keep the rear spoiler (4) in the currently extended position while the motor vehicle is moving, wherein the aerodynamic force acting on the rear spoiler (4) is determined as a function of this determined electric current and the breakaway force and / or braking force, when the aerodynamic force acting on the extended rear spoiler (4) while the motor vehicle is moving is generally smaller than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics (5), the electric motor (8) is controlled to move the rear spoiler (4) from the current extended position towards a further extended position, wherein the electric current is determined at which the rear spoiler (4) begins or would begin to move from the current extended position towards the further extended position, and wherein the aerodynamic force acting on the rear spoiler (4) is determined as a function of this determined electrical current and the breakaway force and / or braking force.

Description

[0001] The invention relates to a method for operating a rear spoiler and a rear spoiler control unit for carrying out the method.

[0002] Motor vehicles with rear spoilers are well known in practice. A rear spoiler is positioned in the rear area of ​​the motor vehicle. Depending on at least one defined operating condition, such as the speed of the motor vehicle, the rear spoiler can be moved between at least two defined rear spoiler positions, namely at least between a fully retracted rear spoiler position and a fully extended rear spoiler position. Between the fully retracted rear spoiler position and the fully extended rear spoiler position, a rear spoiler can typically assume at least one intermediate position. Adjustment kinematics, which typically comprises a gear and control arms and is actuated by an electric motor, are used to move the rear spoiler between the rear spoiler positions.A rear spoiler control unit controls the electric motor depending on at least one defined operating condition in order to move the rear spoiler in a defined manner.

[0003] A motor vehicle with a rear spoiler is known from DE 10 2016 218 283 A1. According to this prior art, it is known to determine a first expected contact pressure acting on the rear spoiler and a second expected contact pressure acting on the rear spoiler, whereby the operation of the rear spoiler is controlled based on a deviation between the first expected contact pressure and the second expected contact pressure.

[0004] According to DE 10 2016 218 283 A1, the first expected contact pressure is determined based on the current position of the rear spoiler relative to a vehicle body. The second expected contact pressure is determined based on an electric current used to move the electric motor to move the rear spoiler from the current position to another position.

[0005] DE 10 2015 002 715 A1 and WO 2013 / 117 539 A1 each disclose a method for operating a roof spoiler of a truck.

[0006] WO 2007 / 095 886 A1 relates to the structural design of an air guiding device for a vehicle.

[0007] To operate a rear spoiler, it is desirable to determine the aerodynamic force acting on it. This has been difficult to date. Therefore, there is a need for a rear spoiler control unit and a method for operating a rear spoiler that can easily and reliably determine the aerodynamic force acting on the rear spoiler while the vehicle is moving.

[0008] The object of the invention is to provide a novel method for operating a rear spoiler and a rear spoiler control unit for carrying out the method.

[0009] This object is achieved by a method for operating a rear spoiler according to patent claim 1.

[0010] When the rear spoiler assumes a currently extended position while the motor vehicle is moving, an electric current is detected, which is used to drive the electric motor to hold the rear spoiler in the currently extended position while the motor vehicle is moving or to move it from the currently extended position toward a more extended position while the motor vehicle is moving. An aerodynamic force acting on the rear spoiler is determined based on this detected electric current.

[0011] The rear spoiler's adjustment kinematics are self-locking and / or mechanically braked.

[0012] Based on a signal provided by a position sensor assigned to the rear spoiler, a check is carried out to determine whether the aerodynamic force acting on the extended rear spoiler while the motor vehicle is moving is generally smaller or generally greater than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics.

[0013] If the aerodynamic force acting on the extended rear spoiler while the vehicle is moving is generally greater than the breakaway force and / or braking force of the adjustment kinematics, the electrical current is determined with which the electric motor is controlled in order to actually keep the rear spoiler in the extended position while the vehicle is moving.

[0014] If the aerodynamic force acting on the extended rear spoiler while the vehicle is moving is generally smaller than the breakaway force and / or braking force of the adjustment kinematics, the rear spoiler control unit controls the electric motor to move the rear spoiler from its current extended position toward a further extended position, while virtually holding the rear spoiler in its current extended position. The electric current at which the rear spoiler just begins, or would begin, to move from its current extended position toward the further extended position is then determined.

[0015] The aerodynamic force acting on the rear spoiler depends on the respective determined electrical current and the breakaway force and / or braking force.

[0016] When the aerodynamic force acting on the rear spoiler while driving is generally greater than the breakaway force and / or braking force of the adjustment kinematics, i.e. when the aerodynamic force acting on the rear spoiler moves the rear spoiler from its currently extended position towards a further retracted position, the rear spoiler control unit controls the rear spoiler with an electric current in such a way that the rear spoiler maintains its currently extended position despite the aerodynamic force acting on it.

[0017] Depending on this electrical current, the aerodynamic force acting on the rear spoiler can also be easily and reliably determined as a function of the breakaway force and / or braking force.

[0018] If, while the vehicle is moving, the aerodynamic force acting on the extended rear spoiler is fundamentally smaller than the breakaway force and / or braking force of the adjustment kinematics, the rear spoiler can be held passively in its currently extended position solely on the basis of the breakaway force and / or braking force, without it being necessary to apply a corresponding force to the adjustment kinematics via the electric motor. In order to nevertheless determine the aerodynamic force acting on the rear spoiler, the electric motor is controlled by the rear spoiler control unit with a current that is required to move the rear spoiler from its currently extended position towards a further extended position, without the rear spoiler actually leaving its currently extended position. The current at which the rear spoiler just starts or stops is therefore determined.would begin to shift from the currently extended position toward the further extended position. Based on this electrical current, the aerodynamic force acting on the rear spoiler can be easily and reliably determined, again as a function of the breakaway force and / or braking force.

[0019] Preferably, the rear spoiler control unit uses the determined aerodynamic force to regulate or control the operation of the rear spoiler. This enables particularly advantageous operation of the rear spoiler.

[0020] The rear spoiler control unit for implementing the method is defined in claim 4. Preferred developments of the invention emerge from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. In the drawing: Fig. 1 a section of the rear area of ​​a motor vehicle; Fig. 2 a block diagram to further clarify the invention.

[0021] Fig. Figure 1 shows a section of the rear section 1 of a motor vehicle in the area of ​​a rear wheel 2, a rear window 3, and a rear spoiler 4. The rear spoiler 4 can be moved between defined rear spoiler positions using an adjustment kinematics 5, which includes a gear 6 and control arms 7. The rear spoiler 4 is moved using an electric motor 8, which acts on the control arms 7 via the gear 6. The electric motor 8 is controlled by a rear spoiler control unit 9.

[0022] The rear spoiler control unit 9 controls the electric motor 8 depending on at least one defined operating condition of the motor vehicle in order to displace the rear spoiler 4 via the adjustment kinematics 5, on which the electric motor 8 acts, in particular in order to displace the rear spoiler 4, starting from a first defined rear spoiler position into a second defined rear spoiler position.

[0023] The first defined rear spoiler position can be a fully retracted rear spoiler position, and the second defined rear spoiler position can be a fully extended rear spoiler position. It is possible that the rear spoiler 4 can assume an intermediate position between the fully retracted rear spoiler position and the fully extended rear spoiler position.

[0024] The present invention relates to details by which the aerodynamic force acting on an extended rear spoiler 4 during travel of the motor vehicle can be safely and reliably determined. To determine the aerodynamic force acting on the extended rear spoiler 4 during travel, the invention proposes a rear spoiler control unit 9 and a method for operating the rear spoiler 4 of the motor vehicle.

[0025] When the rear spoiler 4 assumes a currently extended position while the motor vehicle is traveling, an electric current is determined, which is used to control the electric motor 8 in order to hold the rear spoiler 4 in the currently extended position while the motor vehicle is traveling or to move it from the currently extended position towards a further extended position while the motor vehicle is traveling, without the rear spoiler 4 actually leaving the currently extended position. Depending on this determined electric current, the aerodynamic force acting on the rear spoiler 4 is then determined. This method is carried out by the rear spoiler control unit 9, which, on the one hand, controls the electric motor 8 with an electric current and determines this electric current, and, depending on this electric current, determines the aerodynamic force acting on the rear spoiler 4.

[0026] Further details of the invention will be explained with reference to the signal flow diagram of Fig. 2, specifically for the preferred case in which the adjustment kinematics 5 of the rear spoiler 4 is self-locking and / or mechanically braked.

[0027] For example, the gear 6, through which the electric motor 8 acts on the control arms 7 of the adjustable kinematics 5, can be designed to be self-locking. Alternatively or additionally, the adjustable kinematics 5 can also be mechanically braked.

[0028] In a block 11 of the signal flow diagram of the Fig. Block 2 checks whether the rear spoiler 4 is currently in an extended position while the motor vehicle is moving, and whether the aerodynamic force acting on the rear spoiler 4 should be determined. If this is the case, the system branches from block 11 to block 12 of the signal flow diagram 2.

[0029] In block 12, it is checked whether, while the motor vehicle is traveling, the aerodynamic force acting on the extended rear spoiler 4 is fundamentally greater than a breakaway force and / or braking force or a breakaway torque and / or braking torque of the adjustment kinematics 5, or whether the aerodynamic force acting on the rear spoiler 4 is fundamentally smaller than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5. For this purpose, in the exemplary embodiment shown, a signal detected by a position sensor 10 assigned to the rear spoiler 4 and provided to the rear spoiler control unit 9 is evaluated.

[0030] If the aerodynamic force acting on the extended rear spoiler 4 is greater than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5, the aerodynamic force is large enough to move the rear spoiler 4 from its currently extended position towards a more retracted position. This can be detected by the position sensor 10. In this case, the electric motor 8 is controlled by the rear spoiler control unit 9 with an electric current in order to hold the rear spoiler 4 in its currently extended position while the motor vehicle is driving. Although in this case the aerodynamic force acting on the rear spoiler 4 attempts to move the rear spoiler 4 into a more retracted position, a force is then applied to the adjustment kinematics 5 via the electric motor 8.A moment is applied that is just sufficient to actually hold the rear spoiler 4 in its currently extended position against the aerodynamic force. This occurs in block 13 of the signal flow diagram of the . Fig. 2. If, based on the signal provided by position sensor 10, it is determined that the aerodynamic force acting on the extended rear spoiler 4 is fundamentally greater than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5, then the system branches from block 12 to block 13, wherein in block 13 the rear spoiler control unit 9 then controls the electric motor 8 with an electric current that is just sufficient to hold the rear spoiler 4 in its currently extended position, thus counteracting the amount of force by which the aerodynamic force acting on the rear spoiler 4 is greater than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5.

[0031] In a block 14, the aerodynamic force acting on the rear spoiler 4 is then determined depending on the determined electrical current and the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5 known on the control side.

[0032] If it is determined in block 12 on the basis of the signal provided by the position sensor 10 that the aerodynamic force acting on the extended rear spoiler 4 while the motor vehicle is moving is fundamentally smaller than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5, then starting from block 12, block 15 of the signal flow diagram of the Fig. 2 branches.

[0033] In this case, the electric motor 8 does not need to be energized to hold the rear spoiler 4 in its extended position, since the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5 is sufficient to hold the rear spoiler in the extended position. Nevertheless, in block 15, the electric motor 8 is controlled by an electric current from the rear spoiler control unit 9 in order to move the rear spoiler 4 from the currently extended position towards a further extended position. For this purpose, the electric current with which the electric motor 8 is controlled is increased continuously or discontinuously in stages in block 15. In a block 16 of the Fig.2 it is then checked whether the electric current with which the electric motor 8 is controlled in block 15 is sufficient to move the rear spoiler 4, whereby for this purpose the signal provided by the position sensor 10 of the rear spoiler 4 is again evaluated.

[0034] If the electrical current provided in block 15 is not sufficient to move the rear spoiler 4 from its currently extended position towards a further extended position, the position sensor 10 detects no change and, starting from block 16, a branch is made back to block 15 and the electrical current with which the electric motor 8 is controlled is increased.

[0035] If, however, it is determined in block 16 that, as a result of the control of the electric motor 8 with the electric current, the rear spoiler 4 is just beginning or is just beginning or would begin to move from the currently extended position towards the further extended position, i.e. if it is determined in block 16 that the position sensor 10 is providing a corresponding signal, then the process branches off from block 16 to block 17.

[0036] In block 17, the electric current controlling the rear spoiler 4 is not increased any further. Instead, the current controlling the electric motor 8 is determined, and at which the rear spoiler 4 has just begun or would begin to move from the currently extended position toward the further extended position.

[0037] In block 17, the electric current with which the electric motor 8 was controlled is then reduced again, since the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5 is already sufficient to hold the rear spoiler 4 in its currently extended position.

[0038] In a subsequent step 18, the aerodynamic force acting on the rear spoiler 4 is determined on the basis of the electrical current determined in block 17 and on the basis of the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5 known on the control side.

[0039] If the aerodynamic force acting on the rear spoiler is actually smaller than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics 5 of the rear spoiler 4, the aerodynamic force acting on the rear spoiler 4 is determined by virtually holding the rear spoiler 4 in its currently extended position. To this end, as already explained above, the electrical control current for the electric motor 8 is successively increased in order to determine the electrical current at which the rear spoiler 4 begins or would begin to move from its currently extended position towards a further extended position, without, however, actually moving the rear spoiler 4 from its currently extended position. Depending on this electrical current and the breakaway force and / or braking force orThe aerodynamic force acting on the rear spoiler 4 can then be determined from the breakaway torque and / or braking torque of the adjustment kinematics 5.

[0040] The aerodynamic force acting on the rear spoiler 4, determined in the above manner, can be used to regulate and / or control the operation of the rear spoiler 4.

[0041] Preferably, the aerodynamic force acting on the rear spoiler 4 is determined cyclically by the rear spoiler control unit 9, i.e., at defined time intervals. It is also possible for the rear spoiler control unit 9 to determine the aerodynamic force in an event-controlled manner, i.e., when a defined operating condition of the motor vehicle is present.

Claims

[1] Method for operating a rear spoiler (4) of a motor vehicle, which has a self-locking and / or mechanically braked adjustment kinematics (5), wherein, depending on at least one defined operating condition of the motor vehicle, an electric motor (8) acting on the rear spoiler (4) is controlled in order to displace the rear spoiler (4) between defined rear spoiler positions, characterized by the fact that on the basis of a signal provided by a position sensor (10) assigned to the rear spoiler (4), it is checked whether the aerodynamic force acting on the extended rear spoiler (4) while the motor vehicle is traveling is generally smaller or generally greater than a breakaway force and / or braking force or a breakaway torque and / or braking torque of the adjustment kinematics (5), when the aerodynamic force acting on the extended rear spoiler (4) while the motor vehicle is moving is generally greater than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics (5), the electric current is determined with which the electric motor (8) is controlled in order to keep the rear spoiler (4) in the currently extended position while the motor vehicle is moving, wherein the aerodynamic force acting on the rear spoiler (4) is determined as a function of this determined electric current and the breakaway force and / or braking force, when the aerodynamic force acting on the extended rear spoiler (4) while the motor vehicle is moving is generally smaller than the breakaway force and / or braking force or the breakaway torque and / or braking torque of the adjustment kinematics (5), the electric motor (8) is controlled to move the rear spoiler (4) from the current extended position towards a further extended position, wherein the electric current is determined at which the rear spoiler (4) begins or would begin to move from the current extended position towards the further extended position, and wherein the aerodynamic force acting on the rear spoiler (4) is determined as a function of this determined electrical current and the breakaway force and / or braking force. [2] Method according to claim 1, characterized bythat the determined aerodynamic force is used to regulate or control the operation of the rear spoiler. [3] Method according to claim 1 or 2, characterized by that the aerodynamic force is determined cyclically. [4] Rear spoiler control unit (9) of a rear spoiler (4) which is designed to carry out the method according to one of claims 1 to 3.

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