Method and control apparatus for actuating a braking device in the drive train of a vehicle with an automatic transmission

Patent metadata

Field	Value
Publication number	US-9809205-B2
Application number	US-201515121488-A
Country	US
Kind code	B2
Filing date	Feb 25, 2015
Priority date	Feb 26, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

A method for activating a braking device in the drive train of a vehicle with an automatic gear box, a gear-side parking brake, and a braking system. The vehicle, starting from a parked position with an engaged parking lock, and under the presence of a starting condition, a control apparatus independent from a driver request, controls the braking system to secure against the vehicle rolling away by until the parking lock is released.

First claim

The invention claimed is:

1. A method for activating a braking device in the drive train of a vehicle with an automatic gear box, with a parking lock and at least one braking system,
securing a parked vehicle having the parking lock in an engaged state against rolling away by at least one of a service brake and an independently operable parking brake;
releasing the parking brake and disengaging the parking lock of the parked vehicle by a control apparatus in response to a starting condition, wherein the parking lock is only released if the vehicle is secured against rolling away by the service brake;
raising a brake pressure of the service brake in the event that the brake pressure of the service brake is insufficient at the time of releasing the parking brake to secure the vehicle against rolling away,
wherein the release of the parking brake and disengagement of the parking lock is only permitted when the brake pressure of the service brake has been reached with which the vehicle is secured against rolling away.

2. The method according to claim 1 , wherein the control apparatus determines if the brake pressure on the service brake activated at the time of releasing the parking brake is adjusted in such a manner that the vehicle is secured against rolling away.

3. The method according to claim 2 , wherein the disengagement of the parking lock is released by the control apparatus if the brake pressure on the service brake is sufficient to prevent the vehicle from rolling away.

4. A method according to claim 1 , wherein the service brake brake pressure for preventing rolling away is reduced by the control apparatus to a level suitable for a non-neutral gear after changing gear, so that driving away is only permitted when a vehicular propulsion of the vehicle is greater than a slope descending force.

5. The method according to claim 1 , wherein the parking brake is reactivated in the event that a driver, having released the parking brake, does not change from a neutral gear of the automatic gearbox to a non-neutral gear within a predetermined period of time.

6. The method according to claim 1 , wherein the at least one control apparatus only operates when the vehicle is parked with an unloaded engaged parking lock.

7. The method according to claim 1 , wherein the starting condition of the vehicle includes at least one of changing a gear from a park position to a non-neutral gear of the automatic gearbox, the releasing of the parking brake, or the engagement of the service brake present.

8. The method according to claim 1 , wherein in a parking condition, the parking lock is only engaged by means of the control apparatus when the vehicle is secured against rolling away by means of the parking brake or the service brake.

9. The method according to 8 , wherein when the parking condition is met and the service brake is engaged, the control apparatus determines whether the brake pressure of the service brake is set such that the vehicle is secured against rolling away.

10. The method according to claim 9 , wherein the engagement of the parking lock is released by the control apparatus if the brake pressure of the service brake present at the parking condition is sufficient to prevent the vehicle from rolling away.

11. The method according to claim 9 , wherein if the brake pressure from the service break at the present parking condition is not sufficient to secure the vehicle against rolling away, the control apparatus automatically raises the brake pressure of the service brake so the vehicle is secured against rolling away, and the engagement of the parking lock is only released once a brake pressure is achieved that secures the vehicle against rolling away.

12. The method according to claim 8 , wherein the control apparatus, when the parking condition is present, activates the parking brake.

13. The method according to claim 12 , wherein the brake pressure of the service brake present to secure the vehicle against rolling away is maintained by the control apparatus until the parking brake applies a parking brake force to prevent the vehicle from rolling away.

14. The method according to claim 13 , wherein a service brake side brake pressure present to secure the vehicle against rolling away is reduced by the control apparatus after reaching a vehicle moving preventative parking brake force.

15. The method according to claim 8 , wherein when the brake pressure of the service brake at the parking condition is not sufficient to secure the vehicle against rolling away, the control apparatus determines whether the parking brake force of the parking brake present at the parking condition is sufficient to secure the vehicle against rolling away, and the engagement of the parking lock is delayed until the service brake side brake pressure or the parking brake force is sufficient to secure the vehicle against rolling away.

16. A method according to claim 8 , wherein selection of a non-neutral gear of the automatic gearbox provides a parking condition where the parking lock controlled by the control apparatus is engaged.

17. The method according to claim 1 , wherein the control apparatus controls the activation or deactivation of the parking lock, including a pawl of the parking lock, controls a detection, maintenance, or generation of the brake pressure of the service brake, including at least one brake cylinder on at least one vehicle wheel, and controls the activation or deactivation of the parking brake when the vehicle is secured against rolling away.

18. A method according to claim 1 , wherein the control apparatus only operates the braking device when the vehicle is parked on a slope.

19. A control apparatus for activating a braking device in the drive train of a vehicle, comprising:
an automatic gear box;
a parking lock comprising a gear-side parking lock;
a service brake; and
a parking brake,
wherein, when a parked vehicle is parked and the parking lock can disengage so long as the vehicle is secured against rolling away by at least one of the service brake and parking brake until the parking lock is released,
wherein disengagement of the parking lock, starting from the parked vehicle with the parking lock in an engaged state and the parking brake in an engaged state, when loosening the parking brake, the parking brake is only released by the control of the control apparatus if the vehicle is secured from rolling away by means of the service brake,
wherein the parking brake is released and the parking lock is disengaged by the control apparatus in response to a starting condition, wherein the parking lock is only released if the vehicle is secured against rolling away by the service brake;
wherein a brake pressure of the service brake is raised in the event that the brake pressure of the service brake is insufficient at the time of releasing the parking brake to secure the vehicle against rolling away,
wherein the release of the parking brake and the disengagement of the parking lock is only permitted when the brake pressure has been reached with which the vehicle is secured against rolling away.

20. The control apparatus according to claim 19 , further comprising at least one sensor or actuator to engage the parking lock a parking condition is met only when the vehicle is secured against rolling away by the parking brake or service brake.

Assignees

• Audi Ag

Inventors

• Förster Kilian
• Wohnert Dietmar

Classifications

• B60T7/122 Primary

  for locking of reverse movement · CPC title

• B60T1/005

  by locking of wheel or transmission rotation · CPC title

• B60T2201/06

  Hill holder; Start aid systems on inclined road · CPC title

• F16H63/486

  Common control of parking locks or brakes in the transmission and other parking brakes, e.g. wheel brakes · CPC title