Torque hole filling in a hybrid vehicle during automatic transmission shifting

• US 8,808,141 B2
• Filed: 03/15/2013
• Issued: 08/19/2014
• Est. Priority Date: 05/07/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Shelton, Matthew John, Teslak, Christopher John, Dai, Zhengyu
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US13/834,976
• Publication Number:
  US 20130296127A1
• Time in Patent Office: 522 Days
• Field of Search: None
• US Class Current: 477/5
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• 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 10/115 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2050/0008 Feedback, closed loop systems or details of feedback error signal
• CPC Class Codes: B60W 2510/1025 Input torque
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/1022 Input torque
• 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
• CPC Class Codes: Y10S 903/902 Prime movers comprising electrical and internal combustion motors

Abstract

A system and method for reducing torque disturbances during a shift event for a hybrid vehicle having an engine selectively coupled to a traction motor and an automatic transmission to control or compensate actual transmission input shaft torque based on measured transmission input torque by controlling a torque source, such as a traction motor. The system and method may include an engine, a transmission, a traction motor between the engine and the transmission with the engine being selectively coupled to the motor and the transmission by a disconnect clutch and a controller configured to control motor torque to cause an actual transmission input shaft torque to achieve a target transmission input shaft torque during a transmission shift event.

Claims

1. A method for controlling a hybrid vehicle having a traction motor disposed between an engine and a transmission, the engine being selectively coupled to the motor and the transmission by a disconnect clutch, comprising:

controlling motor torque to cause an actual transmission input shaft torque to achieve a target transmission input shaft torque during a transmission shift event.

2. The method of claim 1, further comprising:

controlling motor torque during a torque phase of the transmission shift event using closed-loop control based on measured transmission input shaft torque feedback.

3. The method of claim 1, further comprising:

increasing an engine torque reserve to a desired level when available motor torque is less than a desired transmission input shaft torque increase to reduce torque disturbances during the transmission shift event.

4. The method of claim 3, wherein the desired transmission input shaft torque increase is based on a difference between the actual transmission input shaft torque and the target transmission input shaft torque.

5. The method of claim 3, wherein the desired level of the engine torque reserve is based on a difference between available motor torque and the desired transmission input shaft torque increase.

6. The method of claim 3, wherein available motor torque is based on measured battery state-of-charge and current operating conditions of the motor.

7. The method of claim 3, further comprising:

coordinating control of engine torque and motor torque in a synchronized manner to cause the actual transmission input shaft torque to achieve the target transmission input shaft torque when available motor torque is less than the desired transmission input shaft torque increase.

8. The method of claim 1, wherein the actual transmission input shaft torque is measured from an input torque signal produced by a torque sensor.

9. The method of claim 1, further comprising:

increasing hydraulic pressure of an on-coming clutch (OCC) during a preparatory phase of the transmission shift event to prepare for engagement of the OCC;

reducing torque capacity of an off-going clutch (OGC) during the preparatory phase to prepare for disengagement of the OGC; and

synchronizing control of motor torque, the OCC and the OGC during a torque phase of the transmission shift event.

10. The method of claim 1, wherein the target transmission input shaft torque is based on a desired output shaft torque profile.

11. A hybrid vehicle, comprising:

an engine;

a transmission having gearing defining multiple torque flow paths from an input shaft to an output shaft of the transmission;

a traction motor disposed between the engine and the transmission, the engine being selectively coupled to the motor and the transmission by a disconnect clutch; and

a controller configured to control motor torque to cause an actual transmission input shaft torque to achieve a target transmission input shaft torque during a transmission shift event.

12. The hybrid vehicle of claim 11, wherein the controller is further configured to detect a start of a torque phase of the transmission shift event and control motor torque during the torque phase using closed-loop control based on measured transmission input shaft torque feedback.

13. The hybrid vehicle of claim 11, wherein the controller is further configured to increase an engine torque reserve to a desired level when available motor torque is less than a desired transmission input shaft torque increase necessary to reduce torque disturbances during the transmission shift event.

14. The hybrid vehicle of claim 13, wherein the desired transmission input shaft torque increase is based on a difference between the actual transmission input shaft torque and the target transmission input shaft torque.

15. The hybrid vehicle of claim 13, wherein the desired level of the engine torque reserve is based on a difference between available motor torque and the desired transmission input shaft torque increase.

16. The hybrid vehicle of claim 13, wherein available motor torque is based on measured battery state-of-charge and current operating conditions of the motor.

17. The hybrid vehicle of claim 13, wherein the controller is further configured to coordinate control of engine torque and motor torque in a synchronized manner to cause the actual transmission input shaft torque to achieve the target transmission input shaft torque when available motor torque is less than the desired transmission input shaft torque increase.

18. The hybrid vehicle of claim 11, wherein the actual transmission input shaft torque is measured from an input torque signal produced by a torque sensor coupled to the input shaft of the transmission.

19. The hybrid vehicle of claim 11, wherein the controller is further configured to increase hydraulic pressure of an on-coming clutch (OCC) during a preparatory phase of the transmission shift event to prepare for engagement of the OCC, reduce torque capacity of an off-going clutch (OGC) during the preparatory phase to prepare for disengagement of the OGC and synchronize control of motor torque, the OCC and the OGC during a torque phase of the transmission shift event.

20. The hybrid vehicle of claim 11, the target transmission input shaft torque is based on a desired output shaft torque profile.