Speed Control Strategy

• US 20080195290A1
• Filed: 10/07/2005
• Published: 08/14/2008
• Est. Priority Date: 10/07/2004
• Status: Active Grant

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Spieker, Arnie
• Granted Patent: US 7,925,410 B2
• Time in Patent Office: Days
• US Class Current: 701/72
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 2240/06 Wheel load; Wheel lift
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/1763 responsive to the coefficient of friction between the wheels and the ground surface B60T8/1764 takes precedence
• CPC Class Codes: B60T 8/1766 Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle
• CPC Class Codes: B60T 8/50 having means for controlling the rate at which pressure is reapplied to or released from the brake

Abstract

A method is provided for efficiently decelerating a vehicle having a braking circuit for braking a set of brake actuators. A flow of pressurized brake fluid is generated within the braking circuit. Normal force parameters exerted on each wheel of the braking circuit are determined. At least one respective brake actuator is isolated from receiving pressurized brake fluid for increasing the flow of pressurized brake fluid to a non-isolated wheel of the brake circuit in response to the normal force parameters.

Claims

1. A method for efficiently decelerating a vehicle having a braking circuit for braking a set of brake actuators, the method comprising the steps of:

generating a flow of pressurized brake fluid within said braking circuit;

determining normal force parameters exerted on each wheel of said braking circuit; and

isolating at least one respective brake actuator of said braking circuit from receiving pressurized brake fluid for increasing said flow of pressurized brake fluid to a non-isolated brake actuator of said brake circuit in response to said normal force parameters.

2. The method of claim 1 wherein isolating at least one respective brake actuator includes isolating said at least one brake actuator for a wheel having a lower normal force than a wheel of said non-isolated brake actuator having a higher normal force.

3. The method of claim 1 further comprising the steps of:

generating a flow of pressurized brake fluid within a second braking circuit;

determining normal force parameters exerted on each wheel of said second braking circuit; and

isolating at least one respective brake actuator of said second braking circuit from receiving pressurized brake fluid for increasing said flow of pressurized brake fluid to a non-isolated brake actuator of said second brake circuit in response to said normal force parameters.

4. The method of claim 3 wherein isolating at least one respective brake actuator of said second braking circuit includes isolating said at least one respective brake actuator for a wheel having a lower normal force than a wheel of said non-isolated brake actuator having a higher normal force.

5. The method of claim 1 wherein said step of isolating at least one brake actuator and applying braking to a non-isolated brake actuator is applied during a vehicle stability control operation.

6. A method for efficiently decelerating a vehicle having at least two split braking circuits for supplying pressurized brake fluid to a set of brake actuators, the method comprising the steps of:

generating a flow of said pressurized brake fluid within said at least two braking circuits;

determining normal force parameters exerted on each wheel of each braking circuit; and

isolating at least one respective brake actuator from receiving said pressurized brake fluid for a wheel when braking is initially applied for increasing said flow of pressurized brake fluid to at least one non-isolated brake actuator of a same brake circuit in response to said normal force parameters.

7. The method of claim 6 wherein said at least one respective brake actuator is isolated from receiving said pressurized brake fluid for a wheel having a lower normal force for increasing said flow of pressurized brake fluid to said at least one non-isolated brake actuator for another wheel of said same brake circuit having a higher normal force.

8. The method of claim 7 further comprising the steps of un-isolating each brake actuator for a wheel of each braking circuit after an initial stage of braking for allowing pressurized braking fluid to be applied to all brake actuators.

9. The method of claim 7 wherein braking is applied in a vertical split braking circuit.

10. The method of claim 7 wherein braking is applied in a diagonal split braking circuit.

11. The method of claim 6 wherein said step of isolating at least one brake actuator and applying pressurized braking fluid to a non-isolated brake actuator is applied during a vehicle stability control operation.

12. The method of claim 11 wherein said vehicle stability control operation includes applying anti-lock braking.

13. The method of claim 11 wherein said vehicle stability control operation includes applying traction control.

14. The method of claim 11 wherein said vehicle stability control operation includes applying yaw stability control.

15. The method of claim 11 wherein said vehicle stability control operation includes applying roll mitigation braking.

16. The method of claim 6 wherein said step of generating a flow of pressurized brake fluid is generated in response to a driver'"'"'s braking demand input.

17. The method of claim 6 wherein said step of generating a flow of said pressurized brake fluid is generated in response to a vehicle stability control operation.

18. A method for efficiently decelerating a vehicle, the method comprising the steps of:

generating a flow of said pressurized brake fluid within a braking circuit having at least two brake actuators;

determining normal force parameters exerted on each wheel of said braking circuit; and

isolating said pressurized brake fluid from at least one brake actuator of a wheel of said braking circuit during an initial braking stage in response to said normal force parameters.

19. The method of claim 18 further comprising the steps of applying pressurized brake fluid to all vehicle wheels of said brake circuit after a predetermined period of time.

20. A vehicle stability control system for efficiently decelerating a vehicle, said vehicle stability control system comprising:

a braking circuit for braking a set of brake actuators coupled to a set of wheels;

a brake fluid pressurization system coupled to said braking circuit;

a brake control module for controlling hydraulic pressure to each brake actuator;

a controller having stored a vehicle dynamic model of said vehicle; and

at least one sensor for generating a signal indicative of normal force parameters;

wherein said brake fluid pressurization system generates a flow of pressurized brake fluid within said braking circuit, wherein said at least one respective brake actuator of a wheel is isolated from receiving brake fluid in response to said normal force parameters, and wherein said flow of pressurized brake fluid is increased to at least one non-isolated brake actuator for a wheel of a same brake circuit in response to isolating said at least one brake actuator.

21. The system of claim 20 wherein said normal force parameter is a measured normal force.

22. The system of claim 20 wherein said normal force parameter is a predicted normal force.

23. The system of claim 20 wherein said non-isolated brake actuator has a higher normal force relative to said isolated brake actuator.

24. The system of claim 20 wherein each brake actuator of each braking circuit is un-isolated after an initial stage of braking for allowing pressurized braking fluid to be applied to each brake actuator.

25. The system of claim 20 wherein said brake control module includes a hydraulic braking boost system.

26. The system of claim 20 wherein said brake control module includes a vehicle stability control module for performing a vehicle stability control operation.

27. The system of claim 26 wherein isolating at least one brake actuator and applying pressurized braking fluid to a non-isolated brake actuator is performed during said vehicle stability control operation.

28. The system of claim 20 wherein said vehicle stability control module includes anti-lock brake functionality.

29. The system of claim 20 wherein said vehicle stability control module includes traction control functionality.

30. The system of claim 26 wherein said vehicle stability control module includes yaw stability control functionality.

31. The system of claim 20 wherein said vehicle stability control module includes roll mitigation functionality.

32. The system of claim 20 wherein said braking circuit includes a vertical split braking circuit.

33. The system of claim 20 wherein said braking circuit includes a diagonal split braking circuit.