Method of determining torque limit with motor torque and battery power constraints

• US 7,977,896 B2
• Filed: 09/27/2008
• Issued: 07/12/2011
• Est. Priority Date: 11/01/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Heap, Anthony H., Hsieh, Tung-Ming
• Primary Examiner(s): Leykin; Rita
• Application Number:
  US12/239,761
• Publication Number:
  US 20090115365A1
• Time in Patent Office: 1,018 Days
• Field of Search: 701/99, 701/1, 701/54, 180/65.265, 180/65.285, 903/945, 903/946, 903/947, 298/20, 298/21, 702 63- 65, 477/3, 477/34, 477/40
• US Class Current: 318/9
• 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: B60L 2240/486 Operating parameters
• 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 10/24 including control of energy storage means
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/28 including control of fuel cells
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2050/0029 Mathematical model of the driver
• CPC Class Codes: B60W 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2710/027 : Clutch torque
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 2710/105 : Output torque
• CPC Class Codes: B60W 30/184 : Preventing damage resulting from overload or excessive wear of the driveline
• 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
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

A method to determine a limit torque associated with an electro-mechanical transmission includes determining electric motor torque constraints and battery power constraints. A limit torque function and a standard form of the limit torque function are determined. The limit torque function and the motor torque constraints and the battery power constraints are transposed to the standard form to determine a limit torque.

Claims

1. Method to determine a limit torque associated with an electro-mechanical transmission operatively coupled to first and second electric machines electrically connected to an electrical energy storage device to transfer mechanical power to an output member, comprising:

monitoring operation of the electro-mechanical transmission;

determining motor torque constraints of the first and second electric machines and battery power constraints for the electrical energy storage device;

determining a limit torque function and identifying an original form of the limit torque function;

transposing the limit torque function to a standard form;

transposing the motor torque constraints and the battery power constraints;

determining a transposed limit torque in the standard form based upon the transposed limit torque function and the transposed motor torque constraints and the transposed battery power constraints; and

retransposing the transposed limit torque from the standard form to the original form to determine the limit torque in the original form.

2. The method of claim 1, further comprising:

transforming the motor torque constraints of the first and second electric machines and the battery power constraints and the limit torque function antecedent to transposing the limit torque function to the standard form,

retransforming the determined limit torque in the original form, and

controlling the first and second electric machines based upon the retransformed limit torque.

3. The method of claim 1, further comprising controlling operation of the electro-mechanical transmission and the first and second electric machines based upon the limit torque.

4. The method of claim 3, wherein the limit torque comprises an output torque to the output member.

5. The method of claim 3, further comprising the electro-mechanical transmission including a selectively applicable torque transfer clutch and the limit torque comprising a reactive torque of the selectively applied torque transfer clutch.

6. The method of claim 3, further comprising the electro-mechanical transmission including an input member and the limit torque comprising an input torque to the input member.

7. The method of claim 2, comprising determining the transformed limit torque by simultaneously solving the transformed limit torque function, transformed motor torque constraints, and transformed battery power constraints to determine one of a maximum and a minimum transformed limit torque.

8. The method of claim 1, wherein the limit torque comprises a minimum output torque to the output member achievable within the motor torque constraints and battery power constraints.

9. The method of claim 8, wherein the minimum output torque to the output member comprises a maximum regenerative torque output for electric power generation.

10. The method of claim 1, wherein the limit torque comprises a maximum output torque to the output member achievable within the motor torque constraints and the battery power constraints.

11. The method of claim 10, wherein the maximum output torque to the output member comprises a maximum mechanical torque output for tractive power generation.

12. The method of claim 1, wherein the standard form comprises a combination of a minimum torque output from the first electric machine and a maximum torque output from the second electric machine.

13. The method of claim 1, further comprising transposing the motor torque constraints and the battery power constraints consistent with the transposing the limit torque function to the standard form.

14. Method to determine a limit torque associated with an electro-mechanical transmission, operatively coupled to first and second electric machines electrically connected to an electrical energy storage device to transfer mechanical power to an output member, comprising:

monitoring operation of the electro-mechanical transmission;

determining motor torque constraints of the first and second electric machines and battery power constraints for the electrical energy storage device;

determining a limit torque function and identifying an original form of the limit torque function;

transforming the motor torque constraints of the first and second electric machines, the battery power constraints, and the limit torque function to a TX/TY space;

transposing the transformed limit torque function to a standard form comprising a combination of a minimum torque output from the first electric machine and a maximum torque output from the second electric machine;

transposing the transformed motor torque constraints and the transformed battery power constraints;

determining a transposed transformed limit torque in the standard form based upon the transposed transformed limit torque function and the transposed transformed motor torque constraints and the transposed transformed battery power constraints;

retransposing the transposed transformed limit torque from the standard form to the original form to determine the transformed limit torque in the original form; and

retransforming the transformed limit torque in the original form.

15. The method of claim 14, further comprising controlling operation of the electro-mechanical transmission and the first and second electric machines based upon the retransformed limit torque.

16. The method of claim 15, wherein the limit torque comprises an output torque to the output member.

17. The method of claim 14, further comprising the electro-mechanical transmission including a selectively applicable torque transfer clutch and the limit torque comprising a reactive torque of the selectively applied torque transfer clutch.

18. The method of claim 14, further comprising the electro-mechanical transmission including an input member and the limit torque comprising an input torque to the input member.

19. The method of claim 14, comprising determining the transformed limit torque by simultaneously solving the transformed limit torque function, transformed motor torque constraints, and transformed battery power constraints to determine one of a maximum and a minimum transformed limit torque.