Method and apparatus to offload offgoing clutch torque with asynchronous oncoming clutch torque, engine and motor torque for a hybrid powertrain system

• US 8,221,285 B2
• Filed: 10/15/2008
• Issued: 07/17/2012
• Est. Priority Date: 11/04/2007
• 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: Heap, Anthony H., Sah, Jy-Jen F.
• Primary Examiner(s): Young, Edwin A
• Application Number:
  US12/251,463
• Publication Number:
  US 20090118086A1
• Time in Patent Office: 1,371 Days
• Field of Search: 477/5, 477/77, 477/83, 477/180, 477/181
• US Class Current: 477/5
• 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 10/105 of electric type
• 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 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 2061/0433 by torque supply with an electric motor
• CPC Class Codes: F16H 2306/44 Removing torque from current gears
• CPC Class Codes: F16H 2306/52 Applying torque to new gears
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 63/502 for smoothing gear shifts
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A powertrain includes an electromechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member. A method for controlling the powertrain includes commanding a shift from a first operating range state to a second operating range state, identifying an off-going clutch, controlling torque output from said electric machine to offload reactive torque transmitted through said off-going clutch, selectively applying an oncoming clutch to offload reactive torque transmitted through said off-going clutch, and reducing a clutch torque capacity of said off-going clutch when said reactive torque transmitted through said off-going clutch is substantially zero.

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 selectively transmit mechanical power to an output member, said method comprising:

commanding a shift from a first operating range state to a second operating range state;

identifying an off-going clutch;

controlling torque output from said electric machine to offload reactive torque transmitted through said off-going clutch;

selectively applying an oncoming clutch to offload reactive torque transmitted through said off-going clutch; and

reducing a clutch torque capacity of said off-going clutch when said reactive torque transmitted through said off-going clutch is substantially zero.

2. The method of claim 1, further comprising controlling torque output from a second electric machine to off-load reactive torque transmitted through said off-going clutch.

3. The method of claim 1, wherein selectively applying said oncoming clutch is based upon a torque required to assist said electric machine to fully offload reactive torque transmitted through said off-going clutch.

4. The method of claim 3, further comprising applying an engine torque based upon a torque required to assist said electric machine and said oncoming clutch to fully offload reactive torque transmitted through said off-going clutch.

5. The method of claim 1, wherein selectively applying said oncoming clutch is based upon determining that said oncoming clutch will reduce reactive torque in said off-going clutch.

6. The method of claim 5, wherein determining that said oncoming clutch will reduce reactive torque in said off-going clutch is based upon monitoring slip speed in said oncoming clutch.

7. The method of claim 1, wherein selectively applying said oncoming clutch is based upon determining a clutch energy limit and limiting said applying said oncoming clutch based upon said clutch energy limit.

8. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said method comprising:

initiating a shift event comprising

identifying an off-going clutch to be synchronously offloaded, and

identifying an oncoming clutch to be loaded;

monitoring an electric machine torque capability to offload said off-going clutch;

determining a torque required to assist said electric machine to offload said off-going clutch;

applying torque with said electric machine to offload said off-going clutch; and

selectively applying torque through said oncoming clutch based upon said torque required to assist said electric machine to offload said off-going clutch.

9. The method of claim 8,

wherein monitoring an electric machine torque capability to offload said off-going clutch comprises

monitoring a torque capability for said electric machine, and

monitoring a torque capability of a second electric machine;

and

further comprising applying torque with said second electric machine to offload said off-going clutch.

10. The method of claim 8, further comprising:

determining a torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch; and

applying torque with said engine based upon said determining said torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch.

11. The method of claim 8, further comprising:

determining a clutch energy limit based upon intended operation of said oncoming clutch; and

wherein said selectively applying torque through said oncoming clutch is further based upon said clutch energy limit.

12. Apparatus for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said apparatus comprising:

an identified off-going clutch;

an identified oncoming clutch; and

a powertrain control system including programming to

monitor a torque capability of said electric machine to offload reactive torque from said off-going clutch,

determine a torque required to assist said electric machine to offload said off-going clutch,

command torque from said electric machine to offload said off-going clutch, and

selectively command torque through said oncoming clutch based upon said torque required to assist said electric machine to offload said off-going clutch.

13. The apparatus of claim 12, wherein said powertrain control system further includes programming to

monitor a torque capability of a second electric machine to offload reactive torque from said off-going clutch, and

command torque from said second electric machine to offload said off-going clutch.

14. The apparatus of claim 12, wherein said powertrain control system further includes programming to

determine a torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch, and

command torque from said engine based upon said determining said torque required to assist said electric machine and said oncoming clutch to offload said off-going clutch.

15. The apparatus of claim 12, wherein said powertrain control system further includes programming to

determine a clutch energy limit based upon intended operation of said oncoming clutch, and

limit said selectively commanded torque through said oncoming clutch based upon said clutch energy limit.