Extending hybrid electric vehicle regenerative braking

• US 9,592,832 B2
• Filed: 03/18/2014
• Issued: 03/14/2017
• Est. Priority Date: 03/18/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, Inc. (Ford Motor Company)
• Inventors: Nedorezov, Felix, Jiang, Hong, Dai, Zhengyu, Yamazaki, Mark S., Colvin, Daniel S.
• Primary Examiner(s): Burgess, Ramya
• Assistant Examiner(s): HANNON, TIMOTHY
• Application Number:
  US14/217,645
• Publication Number:
  US 20150266481A1
• Time in Patent Office: 1,092 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60W 10/026 of lock-up clutches
• CPC Class Codes: B60W 10/196 acting within the driveline, e.g. retarders
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 2510/0208 Clutch engagement state, e.g. engaged or disengaged
• CPC Class Codes: B60W 2510/0241 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 30/18127 Regenerative braking
• CPC Class Codes: F16H 57/04 Features relating to lubrication or cooling or heatingin hydrokinetic gearing F16H41/30; control of lubrication or cooling in hydrostatic gearing F16H61/4165
• CPC Class Codes: F16H 61/143 using electric control means
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A method for controlling regenerative braking in a hybrid electric powertrain includes using an e-pump to supply fluid to a transmission provided an indication that a torque converter clutch disengagement will occur under current powertrain operating conditions is present, and discontinuing use of the e-pump and using a mechanical pump to supply fluid to the transmission provided the indication that a torque converter clutch disengagement will occur under current powertrain operating conditions is absent.

Claims

1. A method for controlling a hybrid electric powertrain, comprising:

(a) while regenerative braking, using an e-pump to supply fluid to a transmission provided an indication that a torque converter clutch disengagement will occur under current powertrain operating conditions is present;

(b) discontinuing use of the e-pump and using a mechanical pump to supply fluid to the transmission provided the indication that a torque converter clutch disengagement will occur under current powertrain operating conditions is absent.

2. The method of claim 1, wherein in step (a) said indication further comprises, while regenerative braking, using the e-pump to supply fluid to the transmission provided a current vehicle speed is less than a reference vehicle speed.

3. The method of claim 1, wherein in step (a) said indication further comprises, while regenerative braking, using the e-pump to supply fluid to the transmission provided a transmission downshift is pending.

4. The method of claim 1, wherein in step (a) said indication further comprises, while regenerative braking, using the e-pump to supply fluid to the transmission provided wheel brake pressure exceeds a reference wheel brake pressure.

5. The method of claim 1, wherein in step (a) said indication further comprises, while regenerative braking, using the e-pump to supply fluid to the transmission provided vehicle deceleration exceeds a reference vehicle deceleration.

6. The method of claim 1, wherein in step (a) said indication further comprises, while regenerative braking, using the e-pump to supply fluid to the transmission provided a current speed ratio produced by the transmission is greater than or less than a reference range of transmission ratios.

7. The method of claim 1, wherein in step (a) said indication further comprises a scheduled disengagement of the torque converter clutch.

8. The method of claim 1, wherein in step (a) said indication further comprises, while regenerative braking, using the e-pump to supply fluid to the transmission provided slip across the torque converter clutch is greater than a reference slip across the torque converter clutch.

9. The method of claim 1, further comprising:

(c) monitoring one of transmission oil temperature, e-pump diagnostic signals, e-pump duty cycle, and system voltage to determine if the e-pump is currently capable of providing a desired magnitude of hydraulic pressure to the transmission.

10. The method of claim 9, further comprising:

(d) reducing a magnitude of regenerative braking, provided the e-pump is currently incapable of providing the desired magnitude of hydraulic pressure to the transmission as indicated by one of transmission oil temperature, e-pump diagnostic signals, e-pump duty cycle, and system voltage.

11. A method for controlling a hybrid electric powertrain, comprising:

(a) during regenerative braking, turning off an e-pump and using a mechanical pump to supply fluid to a transmission provided a transmission downshift is not pending and a vehicle speed is not less than a reference speed;

(b) during regenerative braking, starting the e-pump to supply fluid to the transmission provided the transmission downshift is pending or the vehicle speed is less than the reference speed.

12. The method of claim 11 wherein:

step (a) further comprises turning off the e-pump provided the transmission downshift is not pending, the vehicle speed is not less than a reference speed, and a wheel brake pressure does not exceed a reference pressure;

step (b) further comprises turning on the e-pump provided the transmission downshift is pending, the vehicle speed is less than the reference speed, or the wheel brake pressure does not exceed the reference pressure.

13. The method of claim 11 wherein:

step (a) further comprises turning off the e-pump provided the transmission downshift is not pending, the vehicle speed is not less than a reference speed, and a vehicle deceleration does not exceed a reference deceleration;

step (b) further comprises turning on the e-pump provided the transmission downshift is pending, the vehicle speed is less than the reference speed, or the vehicle deceleration exceeds the reference deceleration.

14. The method of claim 11 wherein:

step (a) further comprises turning off the e-pump provided the transmission downshift is not pending, the vehicle speed is not less than a reference speed, and a slip across a torque converter clutch does not exceed a reference slip;

step (b) further comprises turning on the e-pump provided the transmission downshift is pending, the vehicle speed is less than the reference speed, or the slip across the torque converter clutch exceeds the reference slip.

15. The method of claim 11 further comprising:

(c) determining if the e-pump is currently capable of providing a desired magnitude of hydraulic pressure to the transmission;

(d) reducing a magnitude of regenerative braking, provided the e-pump is not currently capable of providing the desired magnitude of hydraulic pressure to the transmission.

16. A method for controlling a hybrid electric powertrain, comprising:

(a) during regenerative braking, turning off an e-pump and using a mechanical pump to supply fluid to a transmission provided a vehicle deceleration does not exceed a reference deceleration and a wheel brake pressure does not exceed a reference pressure;

(b) during regenerative braking, starting the e-pump to supply fluid to the transmission provided the vehicle deceleration exceeds the reference deceleration or the wheel brake pressure exceeds the reference pressure.

17. The method of claim 16 wherein:

step (a) further comprises turning off the e-pump provided the vehicle deceleration does not exceed the reference deceleration, a wheel brake pressure does not exceed a reference pressure, and a transmission downshift is not pending;

step (b) further comprises turning on the e-pump provided the vehicle deceleration exceeds the reference deceleration, the wheel brake pressure exceeds the reference pressure or the transmission downshift if pending.

18. The method of claim 16 wherein:

step (a) further comprises turning off the e-pump provided the vehicle deceleration does not exceed the reference deceleration, a wheel brake pressure does not exceed a reference pressure, and a vehicle speed is not less than a reference speed;

step (b) further comprises turning on the e-pump provided the vehicle deceleration exceeds the reference deceleration, the wheel brake pressure exceeds the reference pressure or the vehicle speed is less than the reference speed.

19. The method of claim 16 further comprising:

(c) determining if the e-pump is currently capable of providing a desired magnitude of hydraulic pressure to the transmission;

(d) reducing a magnitude of regenerative braking, provided the e-pump is not currently capable of providing the desired magnitude of hydraulic pressure to the transmission.