METHOD FOR CONTROLLING REGENERATIVE BRAKING AND FRICTION BRAKING

• US 20090118887A1
• Filed: 10/29/2008
• Published: 05/07/2009
• Est. Priority Date: 11/03/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), Daimler AG (Mercedes-Benz Group AG), GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Chrysler LLC (Stellantis NV)
• Inventors: Logan, Jon K., Rask, Eric M., Minarcin, Monika A., Wang, Jian M.
• Granted Patent: US 8,135,526 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2220/18 Reluctance machines
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/662 Temperature
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/18 Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 1/10 by utilising wheel movement for accumulating energy, e.g. driving air compressors
• CPC Class Codes: B60T 13/586 the retarders being of the electric type
• CPC Class Codes: B60T 2270/604 Merging friction therewith; Adjusting their repartition
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 : including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 : including control of braking systems
• 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 2050/0006 : Digital architecture hierarchy
• CPC Class Codes: B60W 2510/0671 : Engine manifold pressure
• CPC Class Codes: B60W 2510/0676 : Engine temperature
• CPC Class Codes: B60W 2510/1015 : Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2510/104 : Output speed
• CPC Class Codes: B60W 2520/10 : Longitudinal speed
• CPC Class Codes: B60W 2520/28 : Wheel speed
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2540/16 : Ratio selector position
• CPC Class Codes: B60W 2555/20 : Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0605 : Throttle position
• CPC Class Codes: B60W 2710/0616 : Position of fuel or air injector
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 30/18109 : Braking
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: F16H 3/728 : with means to change ratio in the mechanical gearing
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

A vehicle includes a powertrain system and a friction braking system communicating tractive torque with a driveline, the powertrain system including a torque machine, and an energy storage device connected to the torque machine, said torque machine communicating tractive torque with the driveline. A method for controlling regenerative braking and friction braking includes monitoring a vehicle operating point, determining a braking torque request, determining a regenerative braking motor torque ratio based upon the vehicle operating point wherein the regenerative braking motor torque ratio is non-linearly dependent on the vehicle operating point, and actuating the friction brake based upon the regenerative braking motor torque ratio and the braking torque request.

Claims

1. Method for controlling regenerative braking and friction braking in a vehicle, the vehicle comprising a powertrain system and a friction braking system communicating tractive torque with a driveline, the powertrain system including a torque machine, and an energy storage device connected to the torque machine, said torque machine communicating tractive torque with the driveline, the method comprising:

monitoring a vehicle operating point;

determining a braking torque request;

determining a regenerative braking motor torque ratio based upon the vehicle operating point wherein the regenerative braking motor torque ratio is non-linearly dependent on the vehicle operating point; and

actuating the friction brake based upon the regenerative braking motor torque ratio and the braking torque request.

2. The method of claim 1, wherein the vehicle operating point comprises at least one of vehicle speed, vehicle power, and vehicle torque.

3. The method of claim 1, wherein the regenerative braking motor torque ratio is determined based upon the vehicle operating point such that a profile correlating the vehicle operating point to the regenerative braking motor torque ratio comprises a first region in which the regenerative braking motor torque ratio exponentially decreases with decreasing vehicle operating point, a second region in which the regenerative braking motor torque ratio decreases at a substantially constant rate with decreasing vehicle operating point, and a third region in which the regenerative braking motor torque ratio logarithmically decreases with decreasing vehicle operating point.

4. The method of claim 1, wherein the regenerative braking motor torque ratio is determined based upon the vehicle operating point such that a profile correlating the vehicle operating point to the regenerative braking motor torque ratio comprises a region in which the regenerative braking motor torque ratio exponentially decreases with decreasing vehicle operating point.

5. The method of claim 4, wherein the profile correlating the vehicle operating point to the regenerative braking motor torque ratio comprises a regenerative braking transition region for transitioning between pure friction braking and blended friction and regenerative braking.

6. The method of claim 1, wherein the regenerative braking motor torque ratio is determined based upon the vehicle operating point such that a profile correlating the vehicle operating point to the regenerative braking motor torque ratio comprises a region in which the regenerative braking motor torque ratio logarithmically decreases with decreasing vehicle operating point.

7. The method of claim 6, wherein the profile correlating the vehicle operating point to the regenerative braking motor torque ratio comprises a friction braking transition region for transitioning between pure regenerative braking and blended friction and regenerative braking.

8. The method of claim 1, wherein the regenerative braking motor torque ratio is determined based upon vehicle operating point such that a profile correlating the vehicle speed to the regenerative braking motor torque ratio comprises a region in which the regenerative braking motor torque ratio decreases with vehicle speed at a substantially constant rate.

9. The method of claim 1, further comprising determining the regenerative braking motor torque based upon the friction braking torque and the operator torque request.

10. The method of claim 1, further comprising determining a regenerative braking motor torque based upon the friction braking torque and a system constraint.

11. The method of claim 1, further comprising:

providing a first threshold vehicle speed; and

determining a regenerative braking motor torque ratio of less than one when the vehicle speed is less than the first threshold vehicle speed.

12. The method of claim 11, further comprising:

providing a second threshold vehicle speed; and

determining a regenerative braking motor torque ratio of zero when the vehicle speed is less than the second threshold speed.

13. Method for controlling a regenerative braking system and a friction braking system providing braking torque to a driveline of a vehicle, the method comprising:

monitoring speed of the vehicle;

determining a braking torque request;

determining a regenerative braking motor torque ratio based upon the speed of the vehicle such that the regenerative braking motor torque ratio is non-linearly dependent on the speed of the vehicle; and

determining a friction braking torque command for the friction braking system based upon the regenerative braking motor torque ratio.

14. The method of claim 13, further comprising:

determining a regenerative braking motor torque command based upon the regenerative braking motor torque ratio.

15. The method of claim 13, wherein the regenerative braking motor torque ratio is determined based upon vehicle speed such that a profile correlating the speed of the vehicle to the regenerative braking motor torque ratio comprises a region in which the regenerative braking motor torque ratio exponentially increases with increasing vehicle speed.

16. The method of claim 15, wherein the profile correlating the vehicle speed to the regenerative braking motor torque ratio comprises a regenerative braking transition region for transitioning between pure friction braking and blended friction and regenerative braking.

17. The method of claim 13, wherein the regenerative braking motor torque ratio is determined based upon vehicle speed such that a profile correlating the vehicle speed to the regenerative braking motor torque ratio comprises a region in which the regenerative braking motor torque ratio logarithmically increases with increasing vehicle speed.

18. The method of claim 17, wherein the profile correlating the vehicle speed to the regenerative braking motor torque ratio comprises a friction braking transition region for transitioning between pure regenerative braking and blended friction and regenerative braking.

19. The method of claim 13, wherein the regenerative braking motor torque ratio is determined based upon vehicle speed such that a profile correlating the vehicle speed to the regenerative braking motor torque ratio comprises a region in which the regenerative braking motor torque ratio increases with vehicle speed at a substantially constant rate.

20. Method for controlling regenerative braking and friction braking in hybrid electric vehicle, the vehicle comprising a powertrain system and a friction braking system selectively communicating tractive torque with a driveline, the powertrain system including an engine, an electric machine, and an energy storage device electrically connected to the electric machine, and a transmission device communicating tractive torque between the output member, the engine and the electric machine, the method comprising:

monitoring vehicle speed;

determining a braking torque request;

determining a regenerative braking motor torque ratio based upon the vehicle speed such that the regenerative braking motor torque ratio is non-linearly dependant on vehicle speed; and

determining a friction braking torque command for the friction braking system based upon the regenerative braking motor torque ratio.