Method for vibration damping in the drive train of a motor vehicle and control device therefor

Abstract

Method for vibration damping in the drive train of a motor vehicle, the method comprising: - a detection step (DS) to detect an unwanted vibration in the drive train; - an investigative step (ES) to identify at least one component of the drive train that is related to the unwanted vibration; - a control step (CP) to control at least one actuator of the motor vehicle in order to temporarily influence the interaction between the at least one component of the powertrain and the unwanted vibration; and - a determination step (BS) for determining a termination condition for the control step (AS), wherein, if the termination condition is met, the control operation performed in the control step (AS) is terminated, wherein the termination condition for the control step (AS) is selected from at least one of the following: exceeding a predetermined maximum acceleration value of the motor vehicle (BS1); falling below a predetermined maximum deceleration value of the motor vehicle (BS2).

Description

Technical field

[0001] The present invention relates to a method for vibration damping in the drivetrain of a motor vehicle, in which an actuator of the motor vehicle is controlled to temporarily influence and, in particular, reduce unwanted vibrations in the drivetrain. The invention further relates to a control device configured for vibration damping in the drivetrain of a motor vehicle. State of the art

[0002] Vibrations in a vehicle's drivetrain can lead to uncomfortable driving behavior and shorten the lifespan of vehicle components. Unwanted drivetrain vibrations must therefore be avoided. The causes of unwanted vibrations are very diverse. For example, vibrations can be generated by manufacturing or design-related imbalances in rotating elements. These vibrations can be particularly problematic in the resonance range of the respective element. Currently, these vibrations are either tolerated or influenced by the driver based on experience. For example, the driver can eliminate the vibration by briefly depressing a clutch or brake pedal, which requires experience and can be perceived as disruptive. Description of the invention

[0003] The present invention relates, in a first aspect, to a method for vibration damping in the drivetrain of a motor vehicle. A motor vehicle can be, for example, a construction machine such as a wheel loader or an excavator. Alternatively, a motor vehicle can be a transport vehicle, such as a truck, or an agricultural machine such as a tractor or a combine harvester. Another example of a motor vehicle is a passenger car. The motor vehicle can have an internal combustion engine. Alternatively or additionally, the motor vehicle can have an electric motor. The drivetrain of the motor vehicle can be configured to transmit power from the internal combustion engine or the electric motor to the wheels of the motor vehicle. The drivetrain can comprise several components configured to transmit torque from the internal combustion engine or the electric motor to the wheels of the motor vehicle.For example, the drivetrain can include one or more transmissions or clutches. Additionally, the drivetrain can include at least one rotatably mounted shaft, which is designed to transmit torque from the internal combustion engine or electric motor to the wheels of the vehicle.

[0004] Vibration in the powertrain can be triggered by external influences as well as by design features and vehicle operation. In particular, vibration in the powertrain can be caused by faulty components, such as improperly balanced rotating elements. Vibration damping can be achieved by reducing the amplitude of a vibration frequency. For example, the amplitude can be reduced until a predefined threshold is reached. This threshold can be arbitrarily chosen and can even be zero. Attenuation of the amplitude can be achieved by generating friction along the powertrain. Alternatively or additionally, amplitude reduction can be achieved by introducing power losses into the powertrain. This can create a damping effect that reduces the vibration.

[0005] The procedure includes a detection step to detect unwanted vibration in the drivetrain. A drivetrain vibration can be considered unwanted if the amplitude of the vibration frequency exceeds a predefined threshold. Alternatively or additionally, a drivetrain vibration can be considered unwanted if the duration for which the vibration is detected exceeds a predefined duration. Alternatively or additionally, a drivetrain vibration can be considered unwanted if the vibration occurs at a location along the drivetrain where no vibration occurs during normal vehicle operation. An unwanted vibration can lead to damage to the drivetrain. Alternatively or additionally, an unwanted vibration can lead to a perceptible impairment of the vehicle's handling for the driver.The unwanted vibration can depend on the type of motor vehicle.

[0006] The detection of unwanted vibration can be performed by a detection device designed for electrical signal processing. Detection can be achieved by recording the frequency of the unwanted vibration. Alternatively or additionally, detection can be performed by recording the direction of movement of the component subjected to the unwanted vibration. For example, unwanted vibration can be detected by an accelerometer, which can record the acceleration of a drivetrain component along a predefined direction. The acceleration can be recorded acoustically, optically, or by other means. Alternatively, unwanted vibration can be detected by a speed sensor, which can record the rotational speed and, in particular, the rotational vibration of a drivetrain component.

[0007] The procedure includes an investigative step to identify at least one component of the drivetrain that is associated with the unwanted vibration. This component of the drivetrain could be, for example, a gearbox, a coupling, a rotatably mounted shaft, or a connecting piece between these components. This investigative step can be performed by an investigative device designed for electrical signal processing. Identifying the component of the drivetrain associated with the unwanted vibration can be achieved, for example, by determining the location of a maximum intensity of the unwanted vibration along the drivetrain. This might be the case, for instance, if the unwanted vibration occurs only locally, i.e., originates at the drivetrain component being identified.Determining the location of maximum unwanted vibration intensity can be achieved, for example, by recording the frequency of the unwanted vibration at predetermined positions within the drivetrain and identifying a local extreme value for each recorded vibration frequency. In this case, the component to be identified can be the drivetrain component located in the immediate vicinity of the determined location of the local extreme value.

[0008] The powertrain component could be, for example, a rotating element that is not fully balanced. In this case, the powertrain component could be related to the unwanted vibration in such a way that the unwanted vibration is generated due to the unbalanced rotating element. Alternatively, the powertrain component could be, for example, a torque-transmitting element such as a gearbox or clutch. In this case, the powertrain component could be related to the unwanted vibration in such a way that actuating the torque-transmitting element dampens the unwanted vibration. The component could also be a gearbox housing or another element of the vehicle that can be subjected to unwanted vibration.

[0009] The method comprises a control step for actuating at least one actuator of the motor vehicle in order to temporarily influence the interaction between at least one component of the powertrain and the unwanted vibration. This control step can be performed by a control device designed for electrical signal processing. An actuator of the motor vehicle can be a component of the vehicle designed to convert control signals into mechanical motion or to change physical quantities. For example, the actuator can be actuated to open or close a clutch of the powertrain. Alternatively, the actuator can be actuated to change a gear ratio of a transmission in the powertrain.The actuator can influence the interaction between at least one component of the drivetrain and the unwanted vibration in such a way that the interaction between the drivetrain component and the unwanted vibration is temporarily affected and, in particular, interrupted. Alternatively, the actuator can temporarily attenuate the amplitude of a vibration frequency of the unwanted vibration. Alternatively or additionally, the actuator can change the rotational speed of a rotating component of the drivetrain.

[0010] The procedure includes a determination step to define a termination condition for the control step. If the termination condition is met, the control process performed in the control step can be terminated. The determination of the termination condition can be carried out by a device designed for electrical signal processing. The control process performed in the control step can be terminated, for example, by interrupting a control signal transmitted to the actuator. Alternatively, the control process performed in the control step can be terminated, for example, by transmitting a deactivation signal to the actuator, thereby at least temporarily deactivating the actuator. The termination condition can, for example, be specified by a vehicle manufacturer.Alternatively or additionally, the termination condition can be defined to implement a specific driving behavior, for example, to save fuel or maintain driving safety. The termination condition can be determined, for example, based on a predetermined time duration or based on a predetermined vehicle speed. The termination condition for the control step is selected from at least one of the following: exceeding a predetermined maximum acceleration value of the vehicle; falling below a predetermined maximum deceleration value of the vehicle.

[0011] The proposed method enables the automatic damping of unwanted vibrations in the drivetrain of a motor vehicle. This vibration damping does not require manual intervention from the driver, thereby increasing driving comfort. The unwanted vibration is damped by controlling the vehicle's actuator. The damping of the unwanted vibration can thus be actively influenced by adjusting the actuator's control signal. The vibration damping can therefore be adapted to different types of vehicles and various driving situations. Furthermore, the damping of the unwanted vibration continues only until a termination condition for the control step is met. This ensures that the vibration damping does not unduly affect the vehicle's handling. As a result, the vehicle's driving safety is enhanced.

[0012] According to one embodiment, the detection step comprises acquiring an acceleration or velocity value with respect to the powertrain component. The acceleration value can be acquired directly by means of an accelerometer. Alternatively, a velocity value can be derived from the acceleration value acquired by the accelerometer. The acceleration or velocity value can be acquired directly for the powertrain component. Alternatively, the acceleration or velocity value can be acquired for another vehicle component, which is arranged in a predetermined relation to the powertrain component. From this, an acceleration or velocity value for the powertrain component can be derived.The frequency of a drivetrain component's vibration can be derived from the rate of change of the measured acceleration. Therefore, recording an acceleration or velocity value, for example using an accelerometer, allows for the simple and cost-effective determination of the drivetrain component's vibration frequency.

[0013] In another embodiment, the unwanted vibration is detected based on the amplitude of the measured acceleration or velocity value. The amplitude can be the maximum value of the acceleration or velocity measured over a given period. The amplitude can be measured particularly easily and provides information about the maximum intensity of the unwanted vibration.

[0014] According to another embodiment, the control step is executed when the unwanted vibration is detected for at least a predetermined period. This period can be specified by the vehicle manufacturer. The duration can be adjusted depending on the vehicle's driving conditions. For example, the control step can be executed when the unwanted vibration is detected for a period of several seconds, such as 5 seconds. The duration can be adapted to the specific circumstances. By executing the control step when the predetermined period is exceeded, it can be prevented that the unwanted vibration acts on the drivetrain for so long that it causes damage. The vehicle's service life can thus be improved.

[0015] According to a further embodiment, the investigation step includes determining whether a power flow along the drivetrain is interrupted. A power flow along the drivetrain can, for example, be the transmission of force from the motor vehicle to the wheels of the vehicle via the drivetrain components. For example, the drivetrain components can convert the output torque of the motor into the drive torque of the wheels of the vehicle. At least one sensor for detecting the rotational speed, acceleration value, or velocity value of the respective component can be arranged on at least one or more of the drivetrain components. If at least one of these sensors detects no value or only a minimal value of these parameters, it can be assumed that a power flow along the drivetrain is interrupted.Alternatively, the information on whether the power flow along the drivetrain is interrupted can be provided by a central control unit of the vehicle.

[0016] Furthermore, the investigation step can include determining the point at which the power flow along the drivetrain is interrupted. This determination can be achieved, for example, by identifying the position of sensors mounted on the drivetrain components. By identifying an interruption in the power flow, the origin of the vibration can be determined.

[0017] According to a further embodiment, the method is applied to a motor vehicle with a clutch, wherein the clutch is suitable for influencing the unwanted vibration. The control step comprises at least one of the following: controlling the clutch in the opening direction and controlling the clutch in the closing direction. A clutch can be a component of the drivetrain designed to establish or break an active connection between the engine and a transmission of the motor vehicle. When the clutch is actuated in the closing direction, an active connection can be established. This can influence the unwanted vibration. When the clutch is actuated in the opening direction, an active connection can be broken. This can also influence the unwanted vibration.The actuator can actuate the clutch in the opening direction by converting a control signal into a mechanical movement of the clutch in the opening direction. Similarly, the actuator can actuate the clutch in the closing direction by converting a control signal into a mechanical movement of the clutch in the closing direction. Actuating a clutch allows unwanted vibrations to be dampened in a structurally simple manner.

[0018] According to one embodiment, the clutch can only be actuated in the closing direction up to a predetermined starting value of power flow through the clutch. This predetermined starting value can be reached, for example, when a predetermined minimum value of power flow through the clutch is reached. The predetermined minimum value of power flow can be reached when the clutch is in slippage. Therefore, fully closing the clutch is not necessary to dampen unwanted vibrations. This reduces wear on the clutch and increases its service life.

[0019] According to a further embodiment, the method is applied to a motor vehicle with a starting clutch, wherein the starting clutch is suitable for influencing the unwanted vibration. The control step comprises at least one of the following: controlling the starting clutch in the opening direction and controlling the starting clutch in the closing direction. A starting clutch can be a component of the drivetrain designed to establish or break an effective connection between the engine and the wheels of the motor vehicle. When the starting clutch is actuated in the closing direction, an effective connection can be established. This can influence the unwanted vibration. When the starting clutch is actuated in the opening direction, an effective connection can be broken. This can also influence the unwanted vibration.The actuator can actuate the starting clutch in the opening direction by converting a control signal into a mechanical movement of the starting clutch in the opening direction. Similarly, the actuator can actuate the starting clutch in the closing direction by converting a control signal into a mechanical movement of the starting clutch in the closing direction. Actuating a starting clutch allows unwanted vibrations to be dampened in a structurally simple manner.

[0020] In one embodiment, the starting clutch is only engaged in the closing direction up to a predetermined starting value of power flow through the starting clutch. This predetermined starting value can be reached, for example, when a predetermined minimum value of power flow through the starting clutch is reached. The predetermined minimum value of power flow can be reached when the starting clutch is in slippage. Therefore, fully engaging the starting clutch is not necessary to dampen unwanted vibrations. This reduces wear on the starting clutch and increases its service life.

[0021] According to a further embodiment, the method is applied to a motor vehicle with a torque converter lock-up clutch, wherein the torque converter lock-up clutch is suitable for influencing the unwanted vibration. The control step comprises at least one of the following: controlling the torque converter lock-up clutch in the opening direction; and controlling the torque converter lock-up clutch in the closing direction. A torque converter lock-up clutch can be a component of the drivetrain designed to convert an output torque of the engine into a drive torque of the wheels of the motor vehicle.

[0022] When the torque converter lock-up clutch is actuated in the opening direction, it can be designed so that no torque conversion takes place. This can influence the unwanted vibration. When the torque converter lock-up clutch is actuated in the closing direction, slippage can be generated. This can also influence the unwanted vibration. Actuating the torque converter lock-up clutch in the opening direction can be achieved by the actuator by converting a control signal into a mechanical movement of the lock-up clutch in the opening direction. Actuating the torque converter lock-up clutch in the closing direction can also be achieved by the actuator by converting a control signal into a mechanical movement of the lock-up clutch in the closing direction. By actuating a torque converter lock-up clutch, the unwanted vibration can be dampened in a structurally simple manner.

[0023] In a further embodiment, the method is applied to a motor vehicle equipped with a transmission brake, wherein the transmission brake is suitable for influencing the unwanted vibration. The control step comprises actuating the transmission brake. A transmission brake can be a component of the drivetrain designed to establish or interrupt a power flow through a transmission of the motor vehicle. For example, a transmission brake can block the rotational movement of a shaft attached to the transmission. For example, the transmission brake can generate friction that counteracts the rotational movement of the shaft. This can influence the unwanted vibration. The transmission brake can be actuated by the actuator by converting a control signal into a mechanical movement of the transmission brake.By actuating a transmission brake, the unwanted vibration can be dampened in a structurally simple way.

[0024] According to a further embodiment, the method is applied to a motor vehicle with an electric machine, wherein the electric machine is suitable for influencing the unwanted vibration. The control step comprises controlling the electric machine. An electric machine can be designed to convert electrical energy into kinetic energy. For example, an electric machine can be an electric motor or an electric generator. The unwanted vibration can be influenced by the conversion of electrical energy into kinetic energy. Controlling the electric machine can be achieved, for example, by increasing or decreasing its rotational speed or torque. By controlling the electric machine, the unwanted vibration can be dampened in a structurally simple manner.

[0025] According to one embodiment, the termination condition for the control step is further selected from at least one of the following: exceeding a predetermined maximum procedure duration; exceeding a predetermined maximum load value of the drive train; and falling below a threshold value for the unwanted vibration.

[0026] A predetermined maximum acceleration value of the vehicle may be exceeded if the acceleration measured after the maximum acceleration value has been exceeded is greater than the acceleration measured before the maximum acceleration value was exceeded. A predetermined maximum deceleration value of the vehicle may be undershot if the acceleration measured after the maximum deceleration value has been exceeded is less than the acceleration measured before the maximum deceleration value was exceeded. The maximum procedure duration may, for example, be specified by the vehicle manufacturer.A maximum load value for the drivetrain can be determined, for example, based on a maximum torque or maximum shear force that can act on the drivetrain without impairing its function. A threshold value for the unwanted vibration can be specified, for example, as a vibration frequency, an acceleration, a rotational speed, or a rotational vibration frequency of the component associated with the unwanted vibration. These termination conditions are particularly easy to determine.

[0027] The present invention relates, in a second aspect, to a control device designed for vibration damping in the drivetrain of a motor vehicle. The control device comprises a detection device for detecting unwanted vibrations in the drivetrain. The control device also includes a detection device for identifying at least one component of the drivetrain that is associated with the unwanted vibration. Furthermore, the control device comprises an actuating device for controlling at least one actuator of the motor vehicle in order to temporarily influence the relationship between the at least one component of the drivetrain and the unwanted vibration.The control device comprises a determining device for defining a termination condition for the actuating device, wherein, upon the occurrence of the termination condition, the actuating of the at least one actuator by the actuating device is terminated, wherein the termination condition for the actuating device is selected from at least one of the following: exceeding a predetermined maximum acceleration value of the motor vehicle; falling below a predetermined maximum deceleration value of the motor vehicle. The control device can be configured to execute the procedure described in the first aspect. The embodiments, technical effects, and advantages explained in the first aspect therefore also apply analogously to the control device according to the second aspect. Brief description of the characters Fig. Figure 1 schematically shows a flowchart with steps of a procedure for vibration damping in the drive train of a motor vehicle. Detailed description of embodiments

[0028] Fig. Figure 1 schematically shows a flowchart with steps of a method for vibration damping in the drivetrain of a motor vehicle (not shown). In the exemplary embodiment of the Fig. 1. The drivetrain comprises an internal combustion engine, a clutch, and a driveshaft rotatably mounted between the internal combustion engine and the clutch. The driveshaft is not fully balanced and therefore vibrates in a frequency range that may lie within the driveshaft's resonance range.

[0029] The process begins with a detection step DS to detect an unwanted vibration in the drivetrain. To detect an unwanted vibration, acceleration values ​​of the drivetrain components are recorded using acceleration sensors, and their respective amplitudes are determined. In the exemplary embodiment of the Fig. 1. Acceleration values ​​of the driveshaft are recorded. From these acceleration values, frequency values ​​of a driveshaft oscillation are determined. If the amplitude of the oscillation frequency exceeds a predetermined threshold value for a specified period of time, the driveshaft oscillation is classified as undesirable. In the exemplary embodiment of the Fig. 1. The vibration of the driveshaft is located within its resonance range and is therefore classified as undesirable. This undesirable vibration can lead to uncomfortable vehicle handling and / or damage to the drivetrain. The proposed method makes it possible to automatically dampen this undesirable vibration.

[0030] The method includes an investigation step ES to identify at least one component of the drive train that is related to the unwanted vibration. In the exemplary embodiment of the Fig. The component responsible for the unwanted vibration is the driveshaft. The driveshaft is not fully balanced, which causes it to vibrate.

[0031] This investigation step determines whether a power flow along the drivetrain is interrupted. In the exemplary embodiment of the Fig. 1. The power flow is determined based on torque transmission along the drivetrain from the internal combustion engine via the driveshaft to the clutch. In this determination step, the position at which the power flow along the drivetrain is interrupted is also determined. To determine the position of the interruption, information on the operating state of the vehicle's drive system, which can be provided by a vehicle control unit, is used. Thus, after this determination step, both the drivetrain component associated with the unwanted vibration, in the exemplary embodiment of the Fig. 1. The drive shaft, as well as its position in the drive train and the operating state of the drive are known, from which the suitability of clutches and brakes in the drive train for influencing the unwanted vibration can be determined.

[0032] The process continues with a control step AS. In the control step AS, at least one actuator of the motor vehicle is controlled to temporarily influence the interaction between at least one component of the drivetrain and the unwanted vibration. As already explained, an imbalance in the driveshaft leads to the unwanted vibration. In the exemplary embodiment of the Fig. 1. Torque transmission is interconnected with both the combustion engine and the clutch. By influencing this interaction, the unwanted vibration of the driveshaft can be dampened. Therefore, in a first control step AS1, the clutch is actuated in the opening direction. For this purpose, an actuator of the vehicle is controlled by means of a control signal. The actuator converts this control signal into a movement of the clutch in its opening direction. When the clutch moves in the opening direction, torque transmission via the clutch is influenced or even interrupted. The interaction between the unwanted vibration of the driveshaft and the clutch is thus temporarily interrupted. The unwanted vibration of the driveshaft therefore subsides.

[0033] In an alternative embodiment, the undesired vibration of the driveshaft occurs while the vehicle's clutch is open. In this case, to dampen the undesired vibration, the clutch is actuated in the closing direction in a control step AS2. For this purpose, the vehicle's actuator is controlled by means of a control signal. The actuator converts this control signal into a mechanical movement of the clutch in a closing direction opposite to the opening direction. The clutch is actuated in the closing direction only until a predetermined starting value of a power flow through the clutch is reached. In the embodiment of the Fig. 1 is the specified starting value reached when the clutch is in slippage.

[0034] In another embodiment, the vehicle's drivetrain includes a starting clutch, which interacts with the driveshaft and the internal combustion engine to transmit torque. The undesirable vibration again arises from insufficient balancing of the driveshaft.

[0035] In this embodiment, the detection step DS and the investigation step ES are performed analogously to the previous embodiments. However, in a control step AS3, the starting clutch is controlled in an opening direction by means of an actuator in the vehicle. This temporarily interrupts the interaction between the unwanted vibration of the driveshaft and the starting clutch. The unwanted vibration of the driveshaft thus subsides.

[0036] In an alternative embodiment, the unwanted vibration of the driveshaft occurs while the vehicle's starting clutch is disengaged. In this case, to dampen the unwanted vibration, the starting clutch is actuated in the closing direction in a control step AS4. For this purpose, the vehicle's actuator is controlled by means of a control signal. The actuator converts this control signal into a mechanical movement of the starting clutch in a closing direction opposite to the opening direction. The starting clutch is actuated in the closing direction only until a predetermined starting value of power flow through the starting clutch is reached. In this embodiment, the predetermined starting value is reached when the starting clutch is in slippage.

[0037] In another embodiment, the vehicle's drivetrain includes a torque converter lock-up clutch, which interacts with the driveshaft and the internal combustion engine to transmit torque. The undesirable vibration again arises from insufficient balancing of the driveshaft.

[0038] In this embodiment, the detection step DS and the investigation step ES are performed analogously to the previous embodiments. However, in a control step AS5, the torque converter lock-up clutch is actuated in an opening direction by means of an actuator in the vehicle. This temporarily interrupts the interaction between the unwanted vibration of the driveshaft and the torque converter lock-up clutch. The unwanted vibration of the driveshaft then subsides.

[0039] In an alternative embodiment, the undesired vibration of the driveshaft occurs while the vehicle's torque converter lock-up clutch is open. In this case, to dampen the undesired vibration, the torque converter lock-up clutch is actuated in the closing direction in a control step AS6. For this purpose, the vehicle's actuator is controlled by means of a control signal. The actuator converts this control signal into a mechanical movement of the torque converter lock-up clutch in a closing direction opposite to the opening direction.

[0040] In another embodiment, the vehicle's drivetrain includes a transmission brake, which is operatively connected to the driveshaft and the internal combustion engine for torque transmission. The undesirable vibration again arises due to insufficient balancing of the driveshaft.

[0041] In this embodiment, the detection step DS and the investigation step ES are performed analogously to the previous embodiments. However, in a control step AS7, the transmission brake is controlled by an actuator of the vehicle, so that the transmission brake dampens the rotational movement of the driveshaft. This temporarily interrupts the effect of the unwanted vibration of the driveshaft. The unwanted vibration of the driveshaft then subsides.

[0042] In another embodiment, the vehicle's drivetrain includes an electric machine which is operatively connected to the driveshaft and a clutch for torque transmission. The undesirable vibration again arises due to insufficient balancing of the driveshaft.

[0043] In this embodiment, the detection step DS and the investigation step ES are performed analogously to the previous embodiments. However, in a control step AS8, the electric machine is controlled, thus increasing its torque. This temporarily influences the interaction between the unwanted vibration of the driveshaft and the electric machine. The unwanted vibration of the driveshaft then subsides.

[0044] In an alternative embodiment, the unwanted vibration of the driveshaft occurs while the electric motor generates a comparatively high torque. In this case, the electric motor is controlled in such a way that its torque is reduced. This temporarily interrupts the interaction between the unwanted vibration of the driveshaft and the electric motor. The unwanted vibration of the driveshaft then subsides.

[0045] The control step AS is executed until a termination condition for the control step AS is determined in a determination step BS. If the termination condition is met, the control process performed in the control step is terminated. In the exemplary embodiment of the Fig.1. The first control step AS1 is executed until a predefined maximum acceleration value of the vehicle is exceeded. In a first determination step BS1, exceeding the maximum acceleration value is defined as the termination condition. The actuation of the actuator in the control step AS is terminated, and the detection step DS is executed again.

[0046] Exceeding a predetermined maximum acceleration value of the motor vehicle can also be determined in the determination step BS1 as a termination condition for the control steps AS2 to AS8.

[0047] In another embodiment, the control step AS1 is executed until a predetermined maximum deceleration value of the vehicle is undershot. In a second determination step BS2, falling below the maximum deceleration value is defined as the termination condition. The actuation of the actuator in the control step AS is terminated, and the detection step DS is executed again.

[0048] The failure to fall below a predetermined maximum deceleration value of the motor vehicle can also be determined in the determination step BS2 as a termination condition for the control steps AS2 to AS8.

[0049] In another embodiment, the control step AS1 is executed until a predefined maximum process duration is exceeded. In a third determination step BS3, exceeding the maximum process duration is defined as the termination condition. The actuation of the actuator in the control step AS is terminated, and the detection step DS is executed again.

[0050] Exceeding a predetermined maximum procedure duration can also be determined in the determination step BS3 as a termination condition for the control steps AS2 to AS8.

[0051] In another embodiment, the control step AS1 is executed until a predefined maximum load value of the drive train is exceeded. In a fourth determination step BS4, exceeding the predefined maximum load value of the drive train is defined as the termination condition. The control of the actuator in the control step AS is terminated, and the detection step DS is executed again.

[0052] Exceeding a predetermined maximum load value of the drive train can also be determined as a termination condition for the control steps AS2 to AS8 in the determination step BS4.

[0053] In another embodiment, the control step AS1 is executed until a predefined threshold for the unwanted vibration is undershot. In a fifth determination step BS5, undershooting the threshold for the unwanted vibration is defined as the termination condition. The actuation of the actuator in the control step AS is terminated, and the detection step DS is executed again.

[0054] Falling below a threshold value for the unwanted vibration in the determination step BS5 can also be defined as a termination condition for the control steps AS2 to AS8. Reference sign DS detection step ES investigation step AS control step AS1 Controlling the clutch in the opening direction AS2 Controlling the clutch in the closing direction AS3 Controlling the starting clutch in the opening direction AS4 Controlling the starting clutch in the closing direction AS5 Controlling the torque converter lock-up clutch in the opening direction AS6 Controlling the torque converter lock-up clutch in the opening direction AS7 Controlling the transmission brake AS8 Controlling the electric machine BS Determination Step BS1 Exceeding a predetermined maximum acceleration value BS2 Falling below a specified maximum delay value BS3 Exceeding a specified maximum procedure time BS4 Exceeding a predetermined maximum load value of the drivetrain BS5 Falling below a threshold for the unwanted vibration

Claims

[1] Method for vibration damping in the drive train of a motor vehicle, the method comprising: - a detection step (DS) to detect an unwanted vibration in the drive train; - an investigative step (ES) to identify at least one component of the drive train that is related to the unwanted vibration; - a control step (CP) to control at least one actuator of the motor vehicle in order to temporarily influence the interaction between the at least one component of the powertrain and the unwanted vibration; and - a determination step (BS) for determining a termination condition for the control step (AS), wherein, if the termination condition is met, the control operation performed in the control step (AS) is terminated, wherein the termination condition for the control step (AS) is selected from at least one of the following: exceeding a predetermined maximum acceleration value of the motor vehicle (BS1); falling below a predetermined maximum deceleration value of the motor vehicle (BS2). [2] Method according to claim 1, wherein the detection step (DS) comprises detecting an acceleration value or a velocity value with respect to the component of the drive train that is related to the unwanted vibration. [3] Method according to claim 2, wherein the unwanted vibration is detected based on an amplitude of the detected acceleration value or the detected velocity value. [4] Method according to any of the preceding claims, wherein the control step (AS) is executed when the unwanted vibration is detected for at least a predetermined time period. [5] Method according to any of the preceding claims, wherein the investigation step (ES) comprises determining whether a power flow along the drive train is interrupted. [6] Method according to one of the preceding claims, wherein the method is applied to a motor vehicle with a clutch, wherein the clutch is suitable for influencing the unwanted vibration, wherein the actuation step (AS) comprises at least one of the following: actuation of the clutch in the opening direction (AS1); and actuation of the clutch in the closing direction (AS2). [7] Method according to claim 6, wherein the actuation of the switching clutch in the closing direction (AS2) only takes place up to a predetermined starting value of a power flow via the switching clutch. [8] Method according to one of the preceding claims, wherein the method is applied to a motor vehicle with a starting clutch, wherein the starting clutch is suitable for influencing the unwanted vibration, wherein the control step (AS) comprises at least one of the following: controlling the starting clutch in the opening direction (AS3); and controlling the starting clutch in the closing direction (AS4). [9] Method according to claim 8, wherein the actuation of the starting clutch in the closing direction (AS4) only takes place up to a predetermined starting value of a power flow via the starting clutch. [10] Method according to one of the preceding claims, wherein the method is applied to a motor vehicle with a torque converter lock-up clutch, wherein the torque converter lock-up clutch is suitable for influencing the unwanted vibration, wherein the control step (AS) comprises at least one of the following: controlling the torque converter lock-up clutch in the opening direction (AS5); and controlling the torque converter lock-up clutch in the closing direction (AS6). [11] Method according to one of the preceding claims, wherein the method is applied to a motor vehicle with a transmission brake, wherein the transmission brake is suitable for influencing the unwanted vibration, wherein the control step (AS) comprises controlling the transmission brake (AS7). [12] Method according to one of the preceding claims, wherein the method is applied to a motor vehicle with an electric machine, wherein the electric machine is suitable for influencing the unwanted vibration, wherein the control step (AS) comprises controlling the electric machine (AS8). [13] Method according to one of the preceding claims, wherein the termination condition for the control step (AS) is further selected from at least one of the following: exceeding a predetermined maximum procedure duration (BS3); exceeding a predetermined maximum load value of the drive train (BS4); and falling below a threshold value for the unwanted vibration (BS5). [14] Control device which is designed to dampen vibrations in the drive train of a motor vehicle, the control device comprising: - a detection device for detecting an unwanted vibration in the drive train; - a detection device for identifying at least one component of the powertrain that is related to the unwanted vibration; - a control device for controlling at least one actuator of the motor vehicle in order to temporarily influence the relationship between the at least one component of the powertrain and the unwanted vibration; and - a determination device for determining a termination condition for the control device, wherein, when the termination condition is met, the control of the at least one actuator by the control device is terminated, wherein the termination condition for the control device is selected from at least one of the following: exceeding a predetermined maximum acceleration value of the motor vehicle (BS1); falling below a predetermined maximum deceleration value of the motor vehicle (BS2).

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