METHOD AND APPARATUS TO MONITOR OUTPUT OF AN ELECTRO-MECHANICAL TRANSMISSION

• US 20090112412A1
• Filed: 10/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Stanowski, Paul A., Cawthorne, William R., Buur, Hanne, Wozniak, Leonard G.
• Granted Patent: US 8,078,371 B2
• Time in Patent Office: Days
• US Class Current: 701/54
• 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 6/40 characterised by the assembly or relative disposition of components
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60W 10/023 Fluid 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 10/115 with planetary gears
• 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 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/105 Output torque
• 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: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/902 : Prime movers comprising electrical and internal combustion motors

Abstract

Controlling a hybrid powertrain includes monitoring an operator torque request, determining maximum and minimum allowable transmission output torques based upon the operator torque request, determining a commanded transmission output torque, and comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques.

Claims

1. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to transmit mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches, the method comprising:

monitoring an operator torque request;

determining maximum and minimum allowable transmission output torques based upon the operator torque request;

determining a commanded transmission output torque; and

comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques.

2. The method of claim 1, wherein determining the maximum allowable transmission output torque based upon the operator torque request comprises combining the operator torque request, an electrical regeneration torque, and a positive torque offset.

3. The method of claim 2, wherein the positive torque offset comprises an acceleration rate of substantially 0.2 g.

4. The method of claim 2, wherein determining the minimum allowable transmission output torque based upon the operator torque request comprises establishing a minimum threshold torque when the operator torque request is positive.

5. The method of claim 4, wherein the minimum threshold torque comprises an acceleration rate of substantially −

0.15 g.

6. The method of claim 1, wherein determining the minimum allowable transmission output torque based upon the operator torque request comprises subtracting a negative torque offset from the operator torque request when the operator torque request is negative.

7. The method of claim 1, further comprising intervening when the commanded transmission output torque falls outside of one of the maximum and minimum allowable transmission output torques X times out of Y preceding executions of the code.

8. The method of claim 7, wherein intervening comprises adjusting an electric machine torque command.

9. The method of claim 8, adjusting an electric machine torque command comprises shutting down the electric machine.

10. The method of claim 9, further comprising deactivating torque transfer clutches.

11. The method of claim 9, further comprising adjusting an internal combustion engine output torque command.

12. The method of claim 11, wherein adjusting an internal combustion engine torque command comprises shutting down the internal combustion engine.

13. The method of claim 1, wherein monitoring the operator torque request comprises monitoring a magnitude and a rotational direction of the operator torque request.

14. The method of claim 13, further comprising:

determining a commanded rotational direction of the transmission output torque, and

comparing a rotational direction of the operator torque request to the commanded rotational direction of the transmission output torque.

15. The method of claim 14, further comprising deactivating the monitoring of the rotational direction of the operator torque request when a change in the operator torque request exceeds a predetermined threshold.

16. Article of manufacture, comprising a storage medium having a machine-executable program encoded therein to monitor operation of an electro-mechanical transmission adapted to transmit mechanical power flow to an output shaft, the program comprising:

code to monitor an operator torque request and an operator command for rotational direction;

code to determine maximum and minimum allowable transmission output torques based upon the operator torque request;

code to determine a commanded transmission output torque and a rotational direction of the output;

code to compare the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques; and

code to compare the rotational direction of the output to the operator command for rotational direction.

17. The article of claim 16, wherein the code to determine the maximum allowable transmission output torque based upon the operator torque request comprises arithmetically adding the operator torque request, any commanded electrical regeneration torque, and a positive torque offset.

18. The article of claim 16, wherein the code to determine the minimum allowable transmission output torque based upon the operator torque request comprises establishing a minimum threshold torque when the operator torque request is positive.

19. The article of claim 16, wherein the code to intervene comprises one of code to adjust an electric machine output torque, code to deactivate an actuated torque-transfer clutch, and code to adjust an internal combustion engine output torque.

20. Article of manufacture, comprising a storage medium having a machine-executable computer program encoded therein operative to control a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and a plurality of electric machines each adapted for mechanical power flow to an output through selective actuation of a plurality of torque-transfer clutches;

the program comprising;

code to monitor an operator torque request;

code to determine maximum and minimum allowable transmission output torques based upon the operator torque request;

code to determine a regeneration torque;

code to determine electric machine torque commands;

code to determine a commanded transmission output torque based upon the electric machine torque commands; and

code to compare the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques.