HILL ROLL-BACK AND ROLL-FORWARD CONTROL SYSTEMS AND METHODS

• US 20120187750A1
• Filed: 01/21/2011
• Published: 07/26/2012
• Est. Priority Date: 01/21/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: VERNACCHIA, MARK A., KISH, JONATHAN P., MOSCHETTA, JENNIFER A., BURTCH, JOSEPH B., RIZZO, MICHAEL DOUGLAS
• Granted Patent: US 8,833,870 B2
• Time in Patent Office: Days
• US Class Current: 303/10
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 2201/06 Hill holder; Start aid systems on inclined road
• CPC Class Codes: B60T 7/122 for locking of reverse movement

Abstract

A triggering module selectively generates a triggering signal when a vehicle is stopped, a grade of a surface is one of greater than a predetermined positive grade and less than a predetermined negative grade, and a brake pedal position is greater than a predetermined position. A brake actuator provides brake fluid to a braking system when the brake pedal position is greater than the predetermined position. A brake releasing module, after the triggering signal is generated, begins releasing the brake fluid from the braking system a predetermined period after the brake pedal position reaches the predetermined position. A brake applying module selectively operates a brake fluid pump after the triggering signal is generated based on a comparison of a vehicle speed and a predetermined vehicle speed. The brake fluid pump provides brake fluid to the braking system when the brake fluid pump is operated.

Claims

1. A system for a vehicle on a surface, comprising:

a triggering module that selectively generates a triggering signal when the vehicle is stopped, a grade of the surface is one of greater than a predetermined positive grade and less than a predetermined negative grade, and a brake pedal position is greater than a predetermined brake pedal position,

wherein a brake actuator provides brake fluid to a braking system of the vehicle when the brake pedal position is greater than the predetermined brake pedal position;

a brake releasing module that, after the triggering signal is generated, begins releasing the brake fluid from the braking system a predetermined period after the brake pedal position reaches the predetermined brake pedal position; and

a brake applying module that selectively operates a brake fluid pump after the triggering signal is generated based on a comparison of a vehicle speed and a predetermined vehicle speed,

wherein the brake fluid pump provides brake fluid to the braking system when the brake fluid pump is operated.

2. The system of claim 1 wherein the brake releasing module releases the brake fluid from the braking system based on a period between a present time and a time when the triggering signal is generated.

3. The system of claim 2 further comprising a valve actuator module opens a valve that releases brake fluid from the braking system based on a desired valve opening,

wherein the brake releasing module determines the desired valve opening based on the period.

4. The system of claim 2 wherein the brake applying module begins to selectively operate the brake fluid pump when the period is greater than a second predetermined period.

5. The system of claim 1 further comprising a distance determination module that determines a distance traveled since the vehicle was stopped,

wherein the brake releasing module releases the brake fluid from the braking system based on the distance.

6. The system of claim 5 further comprising a valve actuator module opens a valve that releases brake fluid from the braking system based on a desired valve opening,

wherein the brake releasing module determines the desired valve opening based on the distance.

7. The system of claim 5 wherein the brake applying module begins selectively operating the brake fluid pump when the distance is greater than a predetermined distance.

8. The system of claim 1 further comprising a disabling module that selectively disables the brake releasing module and the brake applying module when at least one of the brake pedal position is greater than the predetermined brake pedal position and an accelerator pedal position is greater than a predetermined accelerator pedal position.

9. The system of claim 1 wherein the triggering module generates the triggering signal when the grade is greater than the predetermined positive grade and a desired mode of operation is one of Drive and a forward gear ratio.

10. The system of claim 1 wherein the triggering module generates the triggering signal when the grade is less than the predetermined negative grade and a desired mode of operation is Reverse.

11. A system for a vehicle on a surface, comprising:

a direction triggering module that selectively generates a signal when one of (i) a direction of movement of a vehicle is in a first direction and a desired mode of operation is a second direction that is opposite the first direction and (ii) the direction of movement is in the second direction and the desired mode of operation is in the first direction; and

a brake applying module that selectively operates a brake fluid pump after the signal is generated based on a comparison of a vehicle speed and a predetermined vehicle speed,

wherein the brake fluid pump pumps brake fluid to a braking system of the vehicle when the brake fluid pump is operated, and

wherein a brake actuator provides brake fluid to the braking system based on actuation of a brake pedal.

12. A method for a vehicle on a surface, comprising:

selectively generating a triggering signal when the vehicle is stopped, a grade of the surface is one of greater than a predetermined positive grade and less than a predetermined negative grade, and a brake pedal position is greater than a predetermined brake pedal position,

wherein a brake actuator provides brake fluid to a braking system of the vehicle when the brake pedal position is greater than the predetermined brake pedal position;

after the triggering signal is generated, beginning to release the brake fluid from the braking system a predetermined period after the brake pedal position reaches the predetermined brake pedal position; and

selectively operating a brake fluid pump after the triggering signal is generated based on a comparison of a vehicle speed and a predetermined vehicle speed,

wherein the brake fluid pump provides brake fluid to the braking system when the brake fluid pump is operated.

13. The method of claim 12 further comprising releasing the brake fluid from the braking system based on a period between a present time and a time when the triggering signal is generated.

14. The method of claim 13 further comprising:

opening a valve that releases brake fluid from the braking system based on a desired valve opening; and

determining the desired valve opening based on the period.

15. The method of claim 13 further comprising beginning to selectively operate the brake fluid pump when the period is greater than a second predetermined period.

16. The method of claim 12 further comprising:

determining a distance traveled since the vehicle was stopped; and

releasing the brake fluid from the braking system based on the distance.

17. The method of claim 16 further comprising:

opening a valve that releases brake fluid from the braking system based on a desired valve opening; and

determining the desired valve opening based on the distance.

18. The method of claim 16 further comprising beginning to selectively operate the brake fluid pump when the distance is greater than a predetermined distance.

19. The method of claim 12 further comprising selectively disabling the releasing of the brake fluid from the braking system and the selective operation of the brake fluid pump when at least one of the brake pedal position is greater than the predetermined brake pedal position and an accelerator pedal position is greater than a predetermined accelerator pedal position.

20. The method of claim 12 further comprising generating the triggering signal when one of (i) the grade is greater than the predetermined positive grade and a desired mode of operation is one of Drive and a forward gear ratio and (ii) the grade is less than the predetermined negative grade and a desired mode of operation is Reverse.