Method for controlling regenerative braking in a vehicle

• US 8,204,664 B2
• Filed: 10/29/2008
• Issued: 06/19/2012
• Est. Priority Date: 11/03/2007
• Status: Expired due to Fees

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: Bayerische Motoren Werke AG, GM Global Technology Operations LLC (General Motors Company), Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Inventors: Minarcin, Monika A, Logan, Jon K., Wang, Jian M, Rask, Eric M.
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Shafi, Muhammad
• Application Number:
  US12/260,263
• Publication Number:
  US 20090118888A1
• Time in Patent Office: 1,329 Days
• Field of Search: 701/22, 701/35, 701/208, 701/211, 701/213, 701/300, 701/25, 701/70, 701/84, 180/65.21, 180 651- 658, 340/995.1, 340/995.19, 903/930
• US Class Current: 701/70
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• 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 2240/423 Torque
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60T 2270/604 Merging friction therewith; Adjusting their repartition
• 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 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/18 Braking system
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: F16H 2037/0866 : Power split variators with distributing differentials, with the output of the CVT connected or connectable to the output shaft
• CPC Class Codes: F16H 2037/102 : the input or output shaft of the transmission is connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/104 : Power split variators with one end of the CVT connected or connectable to two or more differentials
• CPC Class Codes: F16H 2037/106 : with switching means to provide two variator modes or ranges
• 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

Abstract

A vehicle includes a friction braking system and a powertrain system including a torque machine operative to react tractive torque input from a wheel of the vehicle. A method for controlling braking in a vehicle includes monitoring operation of the powertrain system, determining a driver intended total brake torque, determining a regenerative braking capacity based upon the operation of the powertrain system, determining a regenerative braking request based upon a time-rate change in the regenerative braking capacity, and determining a motor torque command for the torque machine based upon the regenerative braking request.

Claims

1. Method for controlling braking in a vehicle including a friction braking system and a powertrain system including a torque machine operative to react tractive torque input from a wheel of the vehicle, a microprocessor performs the following steps:

monitoring operation of the powertrain system;

determining a driver intended total brake torque;

determining a regenerative braking capacity based upon the operation of the powertrain system;

determining a regenerative braking request based upon a time-rate change in the regenerative braking capacity comprising determining the regenerative braking request based upon the regenerative braking capacity modified using a first slope regulating function when the time-rate change in the regenerative braking capacity exceeds a threshold and determining the regenerative braking request based upon the regenerative braking capacity modified using a second slope regulating function when the time-rate change in the regenerative braking capacity is within the threshold; and

determining a motor torque command for the torque machine based upon the regenerative braking request;

wherein determining the regenerative braking request based upon the regenerative braking capacity modified using the first slope regulating function when the time-rate change in the regenerative braking capacity exceeds the threshold comprises applying a three-term Weibull function in a forward-fitting large curve fit operation to maximize the regenerative braking request based upon the regenerative braking capacity; and

wherein determining the regenerative braking request based upon the regenerative braking capacity modified using the second slope regulating function when the time-rate change in the regenerative braking capacity is within the threshold comprises applying a three-term Weibull function in a forward fitting small curve fit operation to maximize the regenerative braking request based upon the regenerative braking capacity.

2. The method of claim 1, further comprising determining a braking torque command to the friction brakes based upon the driver intended total brake torque and the regenerative braking request.

3. The method of claim 1, wherein determining the regenerative braking request based upon the regenerative braking capacity modified using the first slope regulating function further comprises determining the regenerative braking request based upon the regenerative braking capacity modified using a slope regulating function determined based upon the time-rate change in the regenerative braking capacity.

4. The method of claim 3, wherein the slope regulating function includes a first curve portion whereat the regenerative braking request increases exponentially with increasing regenerative braking capacity, a second curve portion in which the regenerative braking request increases at a substantially constant rate with increasing regenerative braking capacity near an inflection point, and a third curve portion in which the regenerative braking request logarithmically increases with increasing regenerative braking capacity.

5. The method of claim 3, wherein the slope regulating function includes a first curve portion whereat the regenerative braking request decreases exponentially with decreasing regenerative braking capacity, a second curve portion in which the regenerative braking request decreases at a substantially constant rate with decreasing regenerative braking capacity near an inflection point, and a third curve portion in which the regenerative braking request logarithmically decreases with decreasing regenerative braking capacity.

6. Method for controlling braking in a vehicle including a friction braking system and a powertrain system including a plurality of torque machines operative to react tractive torque input from a driveline, a microprocessor performs the following steps:

monitoring operation of the powertrain system;

determining a driver intended total brake torque;

determining a regenerative braking capacity based upon the operation of the powertrain system;

determining a regenerative braking request based upon the regenerative braking capacity modified using a slope regulating function comprising determining the regenerative braking request based upon the regenerative braking capacity modified using a first slope regulating function when the time-rate change in the regenerative braking capacity exceeds a threshold and determining the regenerative braking request based upon the regenerative braking capacity modified using a second slope regulating function when the time-rate change in the regenerative braking capacity is less than the threshold;

determining motor torque commands for the first and second torque machines based upon the regenerative braking request, and

determining a braking torque command to the friction brakes based upon the driver intended total brake torque and the regenerative braking request.

7. The method of claim 6, further comprising determining the regenerative braking request based upon the regenerative braking capacity modified using the slope regulating function determined based upon the time-rate change in the regenerative braking capacity.

8. Method for controlling braking in a vehicle including a friction braking system and a powertrain system including a torque machine operative to react tractive torque input from a driveline, a microprocessor performs the following steps:

determining a regenerative braking capacity based upon the operation of the powertrain system;

determining a regenerative braking request based upon the regenerative braking capacity modified using a slope regulating function, wherein the slope regulating function comprises a first slope regulating function when the time-rate change in the regenerative braking capacity exceeds a threshold and the slope regulating function comprises a second slope regulating function when the time-rate change in the regenerative braking capacity is less than the threshold;

determining a motor torque command for the torque machine based upon the regenerative braking request, and

determining a braking torque command to the friction brakes based upon the driver intended total brake torque and the regenerative braking request;

wherein determining the regenerative braking request based upon the regenerative braking capacity modified using the first slope regulating function comprises applying a three-term Weibull function in a forward-fitting large curve fit operation to maximize the regenerative braking request based upon the regenerative braking capacity; and

wherein determining the regenerative braking request based upon the regenerative braking capacity modified using the second slope regulating function comprises applying a three-term Weibull function in a forward-fitting small curve fit operation to maximize the regenerative braking request based upon the regenerative braking capacity.