Method for decoupling a power take-off of a motor vehicle transmission while driving a motor vehicle

Patent metadata

Field	Value
Publication number	US-9381808-B2
Application number	US-201414447845-A
Country	US
Kind code	B2
Filing date	Jul 31, 2014
Priority date	Aug 2, 2013
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A method of decoupling a power take-off drive of a motor vehicle transmission during travel of a motor vehicle in which a form-locking shift element of the power take-off drive is controlled for disengaging the power take-off drive. To implement reliable decoupling without interrupting travel of the motor vehicle, if disengagement of the shift element initially did not occur, control of the shift element is immediately implemented the next time a separating clutch, placed between the motor vehicle transmission and a drive engine of the motor vehicle, is actuated and/or a connection of the shift element toward an output side of the motor vehicle transmission is interrupted, over the course of a subsequent gear shift in the motor vehicle transmission. A drive train of a motor vehicle, a computer program product, and a data carrier having the computer program product.

First claim

The invention claimed is:

1. A method of decoupling a power take-off drive ( 4 ) of a motor vehicle transmission ( 1 ) during travel of a motor vehicle, in which a form-locking shift element ( 3 ) is controlled to disengage the power take-off drive ( 4 ), the method comprising the steps of:
initiating control of the shift element, with a transmission control device, to disengage of the shift element,
checking, with the transmission control device, whether the shift element is disengaged,
if the shift element ( 3 ) is not disengaged, implementing, with the transmission control device, further control of the shift element ( 3 ) for decoupling the power take-off drive when at least one of:
a separating clutch (TK), located between the motor vehicle transmission ( 1 ) and a drive engine (AM) of the motor vehicle, is actuated, and
a connection of the shift element ( 3 ), toward an output side (AB) of the motor vehicle transmission ( 1 ), is interrupted during a subsequent gear shift in the motor vehicle transmission ( 1 ), and

further controlling the shift element, with the transmission control unit, to disengage the shift element and decouple the power take-off drive when at least one of the separating clutch is actuated and the connection between the shift element and the output side of the motor vehicle transmission is interrupted.

2. The method according to claim 1 , further comprising the step of, after the shift element ( 3 ) is initially controlled for a first time, checking, with transmission control device, whether the shift element is disengaged and, if the shift element ( 3 ) is not initially disengaged, interrupting control of the shift element, with the transmission control device, for a time and immediately reimplementing control of the shift element, with the transmission control device, when at least one the separating clutch (TK) is next actuated and the connection of the shift element ( 3 ) toward the output side of the motor vehicle transmission is interrupted.

3. The method according to claim 2 , further comprising the step of, between the initial control of the shift element ( 3 ) for the first time and checking disengagement of the shift element, waiting for a time interval (t) to lapse before reimplementing control of the shift element.

4. The method according to claim 1 , wherein the motor vehicle transmission ( 1 ) has a group design and the shift element ( 3 ) is disposed in a countershaft ( 2 ) of a main group (HG), the method further comprising the step of during the subsequent gear shift, implementing, with the transmission control device, a shift into neutral in at least one of the main group (HG) and a range group (BG) of the motor vehicle transmission ( 1 ) disposed downstream of the main group (HG).

5. The method according to claim 1 , further comprising the step of setting, with the transmission control device, a shift force to a maximum shift force during the subsequent gear shift.

6. The method according to claim 1 , further comprising the step of engaging the separating clutch (TK), with the transmission control device, during a subsequent actuation, in a regulated manner up to a point that a drive torque compensates for a drag torque.

7. The method according to claim 1 , further comprising the step of disengaging the separating clutch (TK), with the transmission control device, during a subsequent actuation, in a regulated manner up to a point that a drive torque compensates for a drag torque.

8. A drive train of a motor vehicle comprising:
a motor vehicle transmission ( 1 ) having at least one power take-off drive ( 4 ) that is drivable, via a shift element, during travel of the motor vehicle, the at least one power take-off drive ( 4 ) being disconnectable during, travel of the motor vehicle, by a method in which the shift element is a form-locking shift element ( 3 ) and is controlled, by a transmission control device, to disengage the power take-off drive ( 4 ), the method comprising the steps of:
the transmission control device initiates controlling the shift element to disengage the shift element and decouple the power take-off drive from the motor vehicle transmission,
the transmission control device determining whether or not the shift element is disengaged, if the transmission control device determines that the shift element ( 3 ) did not disengage initially, then the transmission control device initiates further control of the shift element ( 3 ) when at least one of:
a separating clutch (TK), located between the motor vehicle transmission ( 1 ) and a drive engine (AM) of the motor vehicle, is actuated, and
a connection of the shift element ( 3 ), toward an output side (AB) of the motor vehicle transmission ( 1 ), is interrupted during a subsequent gear shift in the motor vehicle transmission ( 1 ), and

the transmission control device further controlling the shift element to disengage the shift element and decouple the power take-off from the motor vehicle transmission.

9. The drive train according to claim 8 , wherein the transmission control device comprises a computer program product which implements the method for decoupling the power take-off drive ( 4 ) of the motor vehicle transmission ( 1 ) by transmitting control commands stored in software contained within the computer program product with which the transmission control device controls engaging and disengaging of the shift element to couple and decouple the power take-off drive from the motor vehicle transmission.

10. The drive train according to claim 9 , wherein a data carrier carries the computer program product.

11. A method of decoupling a power take-off drive ( 4 ) of a motor vehicle transmission ( 1 ) during travel of a motor vehicle, the motor vehicle transmission has a form-locking shift element ( 3 ) which is controllable for coupling and decoupling the power take-off drive, the form-locking shift element being couplable to drive the power take-off drive which drives and auxiliary assembly and decouplable to stop driving the power take-off drive and the auxiliary assembly, the method comprising the steps of:
initiating, with a transmission control device, the method of decoupling the power take-off drive while the motor vehicle is traveling, and when the form-locking shift element is coupling and driving the power take-off drive and the auxiliary assembly, and when a driver requests stopping drive to the auxiliary assembly;
controlling, with the transmission control device, the form-locking shift element to disengage and decouple the power take-off drive;
determining, with the transmission control device, if the form-locking shift element is disengaged;
if the form-locking shift element is disengaged, then, with the transmission control device, terminating the method of decoupling the power take-off drive;
if the form-locking shift element is determined to be engaged, immediately implementing, with the transmission control device, further control of the shift element when at least one of:
a separating clutch, located between the motor vehicle transmission and a drive engine of the motor vehicle, is actuated, and
a connection of the shift element toward an output side of the motor vehicle transmission is interrupted during a subsequent gear shift in the motor vehicle transmission; and

further controlling the form-locking shift element, with the transmission control device, to disengage and decouple the power take-off drive and the auxiliary assembly when at least one of the separating clutch is actuated and the connection between the shift element and the motor vehicle transmission is interrupted.

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Sauter Ingo
• Hafen Thomas
• Moro-Oliveros Melchor

Classifications

• B60Y2300/423

  Control of power take-off clutches · CPC title

• B60K17/28 Primary

  characterised by arrangement, location, or type of power take-off · CPC title

• Y10T477/6403

  Cross-Sectional Technologies · mapped topic

• B60K25/06 Primary

  from the transmission power take-off · CPC title

• F16H63/44

  Signals to the control unit of auxiliary gearing · CPC title