Method and apparatus for executing an asynchronous clutch-to-clutch shift in a hybrid transmission

• US 8,801,567 B2
• Filed: 02/17/2012
• Issued: 08/12/2014
• Est. Priority Date: 02/17/2012
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Demirovic, Besim, Gupta, Pinaki, Kaminsky, Lawrence A., Naqvi, Ali K., Heap, Anthony H., Sah, Jy-Jen F.
• Primary Examiner(s): PANG, ROGER L
• Application Number:
  US13/398,993
• Publication Number:
  US 20130217536A1
• Time in Patent Office: 907 Days
• Field of Search: 477/5, 477/98, 477/115, 180/65.285
• US Class Current: 477/5
• CPC Class Codes: B60K 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60W 10/105 of electric type
• CPC Class Codes: B60W 20/20 Control strategies involving selection of hybrid configuration, e.g. selection between series or parallel configuration
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A hybrid transmission includes first and second electric machines. A method for operating the hybrid transmission in response to a command to execute a shift from an initial continuously variable mode to a target continuously variable mode includes increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode. Upon deactivation of the off-going clutch, torque outputs of the first and second electric machines and the torque of the oncoming clutch are controlled to synchronize the oncoming clutch. Upon synchronization of the oncoming clutch, the torque for the oncoming clutch is increased and the transmission is operated in the target continuously variable mode.

Claims

1. Method for operating a hybrid transmission including first and second electric machines in response to a command to execute a shift from an initial continuously variable mode to a target continuously variable mode, comprising:

increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode;

upon deactivation of the off-going clutch, controlling torque outputs of the first and second electric machines and the torque of the oncoming clutch to synchronize the oncoming clutch; and

upon synchronization of the oncoming clutch, increasing the torque of the oncoming clutch and operating the transmission in the target continuously variable mode, wherein increasing the torque of the oncoming clutch occurs at a rate and a magnitude equivalent to the rate and magnitude of decreasing the torque of the off-going clutch.

2. The method of claim 1, wherein increasing the torque of the oncoming clutch and correspondingly decreasing the torque of the off-going clutch comprises controlling the torque of the oncoming clutch to generate a transmission output torque responsive to an output torque request.

4. The method of claim 1, wherein said shift is commanded in response to an output torque request comprising an operator braking request.

5. The method of claim 1, wherein said shift is commanded in response to an output torque request comprising a deceleration event.

3. Method for operating a hybrid transmission including first and second electric machines in response to a command to execute a shift from an initial continuously variable mode to a target continuously variable mode, comprising:

increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode;

upon deactivation of the off-going clutch, controlling torque outputs of the first and second electric machines and the torque of the oncoming clutch to synchronize the oncoming clutch; and

upon synchronization of the oncoming clutch, increasing the torque of the oncoming clutch and operating the transmission in the target continuously variable mode, wherein increasing torque of the oncoming clutch and correspondingly decreasing the torque of the off-going clutch comprises determining torque of the oncoming clutch in accordance with the following relationship;

6. Method for operating a hybrid transmission configured to operate in one of two continuously variable modes, comprising:

monitoring entrance criteria for executing an asynchronous clutch-to-clutch shift in the hybrid transmission; and

executing the asynchronous clutch-to-clutch shift in response to a command to shift the hybrid transmission from an initial continuously variable mode to a target continuously variable mode when the entrance criteria are satisfied;

wherein the asynchronous clutch-to-clutch shift comprises;

increasing torque of an oncoming clutch associated with operating in the target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in the initial continuously variable mode;

upon deactivation of the off-going clutch, controlling torque outputs of first and second electric machines and the torque of the oncoming clutch to synchronize the oncoming clutch; and

upon synchronization of the oncoming clutch, increasing the torque of the oncoming clutch and operating in the target continuously variable mode, wherein increasing the torque of the oncoming clutch occurs at a rate and a magnitude equivalent to the rate and magnitude of decreasing the torque of the off-going clutch.

7. The method of claim 6:

wherein monitoring entrance criteria comprises monitoring transmission temperature; and

wherein entrance criteria are satisfied when the transmission temperature is greater than a threshold temperature.

8. The method of claim 6, wherein increasing the torque of the oncoming clutch comprises controlling the torque of the oncoming clutch to generate a transmission output torque responsive to an output torque request.

9. The method of claim 6, wherein said shift is commanded in response to an output torque request comprising an operator braking request.

10. The method of claim 6, wherein said shift is commanded in response to an output torque request comprising a deceleration event.

11. Method for operating a hybrid transmission including first and second electric machines and a control module configured to execute an asynchronous clutch-to-clutch shift, comprising:

increasing torque of an oncoming clutch associated with operating in a target continuously variable mode and correspondingly decreasing a torque of an off-going clutch associated with operating in an initial continuously variable mode including controlling the torque of the oncoming clutch to control magnitude of the output torque of the electrically-variable transmission, wherein increasing the torque of the oncoming clutch occurs at a rate and a magnitude equivalent to the rate and magnitude of decreasing the torque of the off-going clutch;

upon deactivation of the off-going clutch, controlling torque outputs of the first and second electric machines and the torque of the oncoming clutch to synchronize the oncoming clutch and to respond to an output torque request; and

upon synchronization of the oncoming clutch, increasing the torque of the oncoming clutch and operating in the target continuously variable mode in response to the output torque request.