Method and controller for operating a drivetrain of a vehicle

Patent metadata

Field	Value
Publication number	US-2022010849-A1
Application number	US-201917291777-A
Country	US
Kind code	A1
Filing date	Nov 7, 2019
Priority date	Nov 7, 2018
Publication date	Jan 13, 2022
Grant date	—

Abstract

A method of operating a vehicle drivetrain for rocking the vehicle free. The drivetrain has a transmission with an input and an output that can be coupled by a clutch. The input and output are connected to a drive aggregate and a drive output, respectively. The clutch is actuated based on driver actuation of an accelerator and a rotational speed of the drive output such that following accelerator actuation, when its actuation decreases, the clutch disengages with a first opening gradient. Then, based on a calculated point in time at which drive aggregate torque upon the clutch corresponds to torque on the clutch from the drive output, the clutch disengages with a second, smaller opening gradient. And depending on a rotational speed of the drive output relative to a limit value, the clutch either initiates or terminates engagement with a first closing gradient.

First claim

1 - 8 . (canceled)

9 . A method of operating a drive-train of a vehicle in order to rock the vehicle free, the drive-train having a drive aggregate ( 1 ), a drive output ( 3 ) and a transmission ( 2 ) which is arranged in the drive-train between the drive aggregate ( 1 ) and the drive output ( 3 ), a shaft ( 5 ) on a drive input side is connected by a controllable clutch ( 4 ) to the drive aggregate ( 1 ) and a shaft ( 6 ) on a drive output side is connected by the clutch ( 4 ) to the drive output ( 3 ), the method comprising:
when a rocking-free operating mode is active for rocking the drive-train free, then depending upon an actuation of an accelerator pedal ( 9 ) by a driver, automatically actuating the clutch is to rock the vehicle free, to rock the vehicle free, automatically actuating the clutch ( 4 ) as a function of actuation of the accelerator pedal ( 9 ) by the driver and as a function of a rotational speed of the drive output ( 3 ), in such manner that initially opening the clutch ( 4 ) with a defined first opening gradient, when the accelerator pedal ( 9 ) is actuated and the actuation of the accelerator pedal ( 9 ) is decreased, thereafter, as a function of a calculated point in time when a value of a torque from the drive aggregate ( 1 ) that acts upon the clutch ( 4 ) corresponds to a torque acting upon the clutch ( 4 ) from the drive output ( 3 ), terminating disengagement of the clutch ( 4 ) with the defined first opening gradient and disengaging the clutch ( 4 ) by a defined second opening gradient, which is smaller than the first opening gradient, then, when a value of a gradient of the rotational speed of the drive output ( 3 ) becomes larger than a limit value, commencing engagement the clutch ( 4 ) with a defined first closing gradient, and then, when the value of the gradient of the rotational speed of the drive output ( 3 ) becomes smaller than a limit value, terminating engagement of the clutch ( 4 ) with the defined first closing gradient.

10 . The method according to claim 9 , further comprising when the engagement of the clutch ( 4 ) with the defined first closing gradient is terminated, maintaining the engagement position of the clutch ( 4 ) constant until the accelerator pedal ( 9 ) is actuated again.

11 . The method according to claim 10 , further comprising when the accelerator pedal ( 9 ) is actuated again, engaging the clutch ( 4 ) with a defined second closing gradient which is larger than the first closing gradient.

12 . The method according to claim 11 , further comprising engaging the clutch ( 4 ) with the second closing gradient until a torque transmitted by the clutch ( 4 ) corresponds to a torque desired by the driver as a function of actuation of the accelerator pedal ( 9 ).

13 . A control unit for operating a transmission of a vehicle, such that when a rocking-free operating mode of the drive-train for rocking the vehicle free is active, the control unit automatically actuates a clutch ( 4 ) to rock the vehicle free, as a function of an actuation of an accelerator pedal ( 9 ) by a driver,
the control unit automatically actuates the clutch ( 4 ) to rock the vehicle free, as a function of actuation of the accelerator pedal ( 9 ) by the driver and as a function of a rotational speed of an drive output ( 3 ), in such manner that when, after an actuation of the accelerator pedal ( 9 ), the actuation of the accelerator pedal ( 9 ) is decreased, the control unit first actuates the clutch ( 4 ) with a defined first opening gradient, then, as a function of a calculated point in time when a value of torque from a drive aggregate ( 1 ) that acts upon the clutch ( 4 ) corresponds to a torque acting upon the clutch ( 4 ) from the drive output ( 3 ), the control unit terminates the disengagment of the clutch ( 4 ) with the defined first opening gradient and actuates the clutch ( 4 ) with a defined second opening gradient, which is smaller than the first opening gradient, and then, if a value of a gradient of the rotational speed of the drive output ( 3 ) becomes larger than a limit value, the control unit actuates the clutch ( 4 ) with a defined first closing gradient, and then, if the value of the gradient of the rotational speed of the drive output ( 3 ) becomes smaller than a limit value, the control unit terminates the engagement of the clutch ( 4 ) with the defined first closing gradient.

14 . The control unit according to claim 13 , wherein when the control unit terminates engagement of the clutch ( 4 ) with the defined first closing gradient, the control unit maintains a closing position of the clutch ( 4 ) constant until the actuation of the accelerator pedal ( 9 ) is increased again.

15 . The control unit according to claim 14 , wherein when new actuation of the accelerator pedal ( 9 ) is increased, the control unit actuates the clutch ( 4 ) with a defined second closing gradient which is larger than the first closing gradient.

16 . The control unit according to claim 15 , wherein with the second closing gradient, the control unit engages the clutch ( 4 ) until a torque transmitted by the clutch ( 4 ) corresponds to a torque desired by the driver that depends on the actuation of the accelerator pedal ( 9 ).

17 . A method of operating a drive-train of a vehicle for rocking the vehicle free from a depression, the drive-train having, in a direction of toque transmission, a drive aggregate ( 1 ) connected to an input shaft ( 5 ) of a transmission ( 2 ), a controllable clutch ( 4 ) having an input side connected to the input shaft and an output side connected to an output shaft ( 6 ) of the transmission, the output shaft ( 6 ) being connected to a drive output ( 3 ), the clutch ( 4 ) being automatically actuatable to disengage and engaged to controllably transmit drive from the input shaft to the output shaft, the method comprising:
activating a rocking-free operating mode for rocking the vehicle free, and automatically actuating the clutch ( 4 ) to rock the vehicle free as a function of actuation of the accelerator pedal by a driver and as a function of a rotational speed of the drive output ( 3 ) such that: disengaging the clutch ( 4 ) with a defined first opening gradient when the accelerator pedal ( 9 ) is actuated and actuation of the accelerator pedal ( 9 ) decreases, terminating the disengagement of the clutch ( 4 ) with the defined first opening gradient and disengaging the clutch ( 4 ) with a defined second opening gradient, which is smaller than the first defined opening gradient, as a function of a calculated point in time when a value of torque from the drive aggregate ( 1 ) that acts upon the clutch ( 4 ) corresponds to torque acting upon the clutch ( 4 ) from the drive output ( 3 ), initiating engagement of the clutch ( 4 ) with a defined first closing gradient when a value of a gradient of the rotational speed of the drive output ( 3 ) is larger than a limit value, and terminating engagement of the clutch ( 4 ) with the defined first closing gradient when the value of the gradient of the rotational speed of the drive output ( 3 ) is smaller than the limit value.

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Leingruber Kai

Classifications

• F16D2500/3027

  Torque · CPC title

• F16D48/06 Primary

  Control by electric or electronic means, e.g. of fluid pressure · CPC title

• F16D2500/30428

  Speed change rate of the output shaft · CPC title

• F16D2500/30412

  Torque of the input shaft · CPC title

• F16D2500/70412

  Clutch position change rate · CPC title