Control system for a hybrid powertrain system

• US 8,827,865 B2
• Filed: 08/31/2011
• Issued: 09/09/2014
• Est. Priority Date: 08/31/2011
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Naqvi, Ali K., Demirovic, Besim, Gupta, Pinaki, Kaminsky, Lawrence A.
• Primary Examiner(s): Holmes, Justin
• Assistant Examiner(s): FLUHART, STACEY A
• Application Number:
  US13/223,052
• Publication Number:
  US 20130053212A1
• Time in Patent Office: 1,105 Days
• Field of Search: 477/5
• US Class Current: 477/5
• 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: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/113 with two input flow paths, e.g. double clutch transmission selection of one of the torque flow paths by the corresponding input clutch
• 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 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A vehicle includes a powertrain with an engine, first and second torque machines, and a hybrid transmission. A method for operating the vehicle includes operating the engine in an unfueled state, releasing an off-going clutch which when engaged effects operation of the hybrid transmission in a first continuously variable mode, and applying a friction braking torque to a wheel of the vehicle to compensate for an increase in an output torque of the hybrid transmission resulting from releasing the off-going clutch. Subsequent to releasing the off-going clutch, an oncoming clutch which when engaged effects operation of the hybrid transmission in a second continuously variable mode is synchronized. Subsequent to synchronization of the oncoming clutch, the oncoming clutch is engaged.

Claims

1. Method for operating a vehicle including a hybrid transmission having first and second torque machines, comprising:

decreasing a clutch pressure of an off-going clutch associated with operating the hybrid transmission in a first continuously variable mode and decreasing a clutch torque holding capacity of the off-going clutch and applying a friction braking torque to a wheel of the vehicle coincident with decreasing the clutch pressure of the off-going clutch;

operating the hybrid transmission in a neutral operating mode and synchronizing an oncoming clutch associated with operating the hybrid transmission in a second continuously variable mode; and

applying the oncoming clutch and coincidentally releasing the applied friction braking torque when the oncoming clutch is synchronized.

2. The method of claim 1, wherein synchronizing the oncoming clutch comprises controlling torque of the first and second torque machines to synchronize the oncoming clutch.

3. The method of claim 2, wherein synchronizing the oncoming clutch comprises synchronizing the oncoming clutch at a predetermined rate.

4. The method of claim 1, wherein applying the oncoming clutch when the oncoming clutch is synchronized comprises increasing a clutch pressure of the oncoming clutch and increasing a clutch torque holding capacity of the oncoming clutch.

5. The method of claim 4, further comprising pre-filling the oncoming clutch prior to applying the oncoming clutch.

6. Method for operating a vehicle including a powertrain including an engine, first and second torque machines, and a hybrid transmission, comprising:

operating the engine in an unfueled state;

releasing an off-going clutch which when engaged effects operation of the hybrid transmission in a first continuously variable mode;

applying a friction braking torque to a wheel of the vehicle to compensate for an increase in an output torque of the hybrid transmission resulting from releasing the off-going clutch;

subsequent to releasing the off-going clutch, releasing the applied friction braking torque and synchronizing an oncoming clutch which when engaged effects operation of the hybrid transmission in a second continuously variable mode; and

subsequent to synchronization of the oncoming clutch, engaging the oncoming clutch.

7. The method of claim 6, wherein operating the engine in the unfueled state comprises operating the engine in an off state.

8. The method of claim 6, wherein operating the engine in the unfueled state comprises operating the engine in a fuel cut-off mode.

9. The method of claim 6, wherein synchronizing the oncoming clutch comprises controlling torque of the first and second torque machines to synchronize the oncoming clutch.

10. The method of claim 9, wherein synchronizing the oncoming clutch comprises synchronizing the oncoming clutch at a predetermined rate.

11. Hybrid vehicle system, comprising:

an internal combustion engine;

at least one electric machine;

a transmission operatively coupled to said internal combustion engine and said at least one electric machine, said transmission including a first clutch which when engaged effects operation of the transmission in a first continuously variable mode and a second clutch which when engaged effects operation of the transmission in a second continuously variable mode;

a friction brake operative on a wheel operatively coupled to the transmission;

a control module effecting a shift of the transmission from the first continuously variable mode to the second continuously variable mode, comprising

operating the engine in an unfueled state;

releasing the first clutch;

applying the friction brake to compensate for an increase in an output torque of the transmission resulting from releasing the first clutch;

subsequent to releasing the first clutch, synchronizing the second clutch; and

subsequent to synchronization of the second clutch, releasing the applied friction brake and engaging the second clutch.