Vehicle System Having Regenerative Brake Control

• US 20080100129A1
• Filed: 09/09/2005
• Published: 05/01/2008
• Est. Priority Date: 09/09/2004
• Status: Active Grant

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Lubbers, Mark D.
• Granted Patent: US 8,152,245 B2
• Time in Patent Office: Days
• US Class Current: 303/113.1
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60T 13/586 the retarders being of the electric type
• CPC Class Codes: B60T 2270/602 ABS features related thereto
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method is provided for controlling the braking of a vehicle that has a first set of friction brakes for applying a first apply brake force to a first set of wheels and a second set of friction brakes for applying a second brake apply force to a second set of wheels. A powertrain assembly is coupled to the second set of wheels. The powertrain assembly includes a regenerative braking unit capable of recapturing kinetic energy from the second set of wheels. The vehicle is braked in a first phase of control using regenerative braking to brake the second set of wheels to achieve up to a first value of braking. The vehicle is braked in a second phase of control using the regenerative braking to maintain braking of the second set of wheels at the first value of braking force while selectively applying the first friction brakes to the first set of wheels up to a second value of braking.

Claims

1. A method of controlling the braking of a vehicle that has a first set of friction brakes for applying a first apply brake force to a first set of wheels, a second set of friction brakes for applying a second brake apply force to a second set of wheels, and a powertrain assembly coupled to said second set of wheels, said powertrain assembly including a regenerative braking unit capable of recapturing kinetic energy from said second set of wheels, said method comprising the steps of:

braking said vehicle in a first phase of control using regenerative braking to brake said second set of wheels to achieve up to a first value of braking; and

braking said vehicle in a second phase of control using said regenerative braking to maintain braking of said second set of wheels at said first value of braking force while selectively applying said first friction brakes to said first set of wheels up to a second value of braking.

2. The method of claim 1 further comprising the step of braking said vehicle in a third phase of control by selectively using said first set of friction brakes to brake said first set of wheels and using said second set of friction brakes to brake said second set of wheels together with a desired amount of regenerative braking when above said second value of braking.

3. The method of claim 2 wherein when braking is applied in said third phase of control, said friction braking of said first set of wheels is greater said friction braking of said second set of wheels for maintaining front bias balance braking control.

4. The method of claim 2 wherein when braking is applied in said third phase of control, said braking of said first set of friction brakes is proportional to said braking of said second set of friction brakes.

5. The method of claim 2 wherein an amount of braking applied to said first set of friction brakes and said second set of friction brakes is determined as a function of a difference between an input vehicle braking demand and the actual regenerative braking applied.

6. The method of claim 1 wherein said step of braking said vehicle in said second phase of control further includes selectively applying said second set of friction brakes together with said first set of friction brakes up to said second value of braking.

7. The method of claim 1 wherein said first set of wheels are front wheels of said vehicle and said second set of wheels are rear wheels of said vehicle.

8. The method of claim 1 wherein said first set of wheels are coupled to a non-driven axle of said vehicle and said second set of wheels are coupled to a driven axle of said vehicle.

9. The method of claim 2 wherein, when braking said vehicle in said third phase of control, said desired amount of regenerative braking decreases as an amount of braking applied by said second set of friction brakes increases.

10. The method of claims 2 wherein, when braking said vehicle in said third phase of control, said desired amount of regenerative braking is decreased preceding the application of said second set of friction brakes.

11. The method of claim 1 wherein, when braking said vehicle in said first phase of control, no friction brakes are used.

12. The method of claim 1 wherein said first value of braking is a maximum output of said regenerative braking torque.

13. The method of claim 1 wherein braking from only said first set of brake and said second set of brakes is applied if a vehicle speed of said is less than a predetermined threshold.

30. The method of claim 1 wherein the step of applying said first friction brakes to said first set of wheels in said second phase of control exceeds a front bias braking balance control of a desired brake balance line.

31. The method of claim 2 wherein the step of braking said vehicle in said third phase of control by applying said first set of friction brakes and said second set of friction brakes includes exceeding a front bias braking control of a desired brake balance line.

14. A method of controlling the braking of a vehicle that has a first set of friction brakes for applying a first brake apply force to a first set of wheels coupled to a non-driven axle, a second set of friction brakes for applying a second brake apply force to a second set of wheels coupled to a driven axle, and a powertrain assembly coupled to said driven axle, said powertrain assembly including a regenerative braking unit capable of recapturing kinetic energy from driven axle, said method comprising the steps of:

braking said vehicle in a first phase of control using regenerative braking to brake said driven axle to achieve up to a first value of braking force;

braking said vehicle in a second phase of control using said regenerative braking to maintain braking of said driven axle at said first value of braking force while selectively applying said first friction brakes to said first set of wheels of said non-driven axle up to a second value of braking force; and

braking said vehicle in a third phase of control by selectively applying said first friction brakes to said first set of wheels and said second friction brakes to said second set of wheels together with a desired amount of regenerative braking when above said second value of braking force.

15. A method of determining brake control between a non-driven axle and a driven axle in a braking system where said braking system includes an electric motor for applying a regenerative braking force to said driven axle, and where said braking system further includes a first set of friction brakes for applying a first brake apply force to a first set of wheels coupled to said non-driven axle and a second set of friction brakes for applying a second brake apply force to a second set of wheels coupled to said driven axle, said method comprising the steps of:

receiving a pressure input command relating to a total braking force for braking a vehicle;

determining if an actual regenerative braking force is greater than said total braking force demand;

if said actual regenerative braking force is greater than said total braking force demand, using said actual regenerative braking force to brake said driven axle up to said total braking force demand;

if said actual regenerative braking force is less than said total braking force demand, determining said first brake apply force to be applied to said first set of friction brakes of said non-driven axle and said second brake apply force to be applied to said second set of friction brakes of said driven axle, said sum of said first brake apply force and said second brake apply force being equal to said total braking force demand;

determining whether said second brake apply force is greater than said actual regenerative braking force;

if said actual regenerative braking force is greater than said second brake apply force, then applying said actual regenerative braking force to said driven axle up to said second brake apply force and applying said first braking force to said first set of friction brakes of said non-driven axle;

if said actual regenerative braking force is less than said second brake apply force, then determining a brake apply difference between said second braking force and said actual regenerative braking force; and

applying said actual regenerative braking force to said driven axle, applying said first brake apply force to said first set of friction brakes of said non-driven axle, and applying said brake apply difference to said second set of friction brakes of said driven axle in response to said regenerative braking force being less than said second brake apply force.

16. The method of claim 15 wherein said actual regenerative braking force applied to said driven axle is applied up to a first value of braking force.

17. The method of claim 16 wherein said actual regenerative braking force applied to said driven axle and said first brake apply force applied to said first set of friction brakes of said non-driven axle are cooperatively applied up to a second value of braking force.

18. The method of claim 17 wherein said actual regenerative braking force applied to said driven axle, said first brake apply force applied to said first set of friction brakes of said non-driven axle, and said brake force difference applied to said second set of friction brakes of said driven axle are cooperatively applied above said second value of braking force.

19. The method of claim 18 wherein said actual regenerative braking force decreases when above said second value of braking.

20. The method of claim 15 wherein braking from only said first set of friction brakes and said second set of friction brakes is applied if a vehicle speed is less than a predetermined threshold.

21. A method of controlling a vehicular regenerative braking system that includes a first set of friction brakes for applying a first brake apply force to a first set of wheels coupled to said non-driven axle, a second set of friction brakes for applying a second brake apply force to a second set of wheels coupled to a driven axle, a powertrain assembly coupled to said second set of wheels, said powertrain assembly including a regenerative braking unit for applying a regenerative braking force to said driven axle, said method comprising the steps of:

determining a desired brake balance line representative of a ratio of braking forces between a first set of brakes of a non-driven axle and a second set of brakes of a driven axle, said desired brake balance ratio having a first, a second, and a third control phase;

applying said regenerative braking force to said driven axle in said first control phase up to a first value of brake force;

cooperatively applying said first brake apply force and said regenerative braking force in said second control phase up to a second value wherein said second value is in a region of front bias braking balance control; and

cooperatively applying said second brake apply force together with said first brake apply force and said regenerative braking force in a third phase of control up to a third value of braking of braking.

22. The method of claim 21 wherein said third value of braking of braking is disposed in said region of said front bias braking balance control.

23. The method of claim 21 wherein said third value of braking of braking is disposed on said desired brake balance line.

24. The method of claim 21 wherein said second value of braking is disposed on said desired brake balance line.

25. The method of claim 21 wherein said second brake apply force is applied in said second control phase.

26. The method of claim 25 wherein a total of said regenerative braking force, said first brake apply force, and said second brake apply force is proportional between said non-driven axle and said second set of wheels of said driven axle so that a ratio of braking forces between said non-driven axle and said driven axle increases along a line parallel to said desired brake balance line throughout said second control phase as a total brake demand increases.

27. The method of claim 21 wherein said regenerative braking force is not applied if a vehicle speed is less than a predetermined threshold.

28. The method of claim 21 wherein the step of said first brake apply force applied in said second phase of control exceeds said front bias braking balance control of said desired brake balance line.

29. The method of claim 22 wherein said first and second brake apply force applied in said third phase of control exceeds said front bias braking balance control of said desired brake balance line.