METHODS AND SYSTEM FOR TRANSITIONING BETWEEN CONTROL MODES WHILE CREEPING

• US 20160031431A1
• Filed: 07/30/2014
• Published: 02/04/2016
• Est. Priority Date: 07/30/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Johri, Rajit, Connolly, Francis Thomas, Liang, Wei, Nefcy, Bernard D., Wang, Xiaoyong, Yamazaki, Mark Steven, Kuang, Ming Lang, Doering, Jeffrey Allen
• Granted Patent: US 9,573,579 B2
• Time in Patent Office: Days
• 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 10/06 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/004 of the clutch
• CPC Class Codes: B60W 2510/0233 of torque converter lock-up clutch
• 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 30/18063 Creeping
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

Systems and methods for transitioning a torque source between speed control and torque control modes during a vehicle creep mode are disclosed. In one example, torque of an electric machine is adjusted in response to a torque converter model. The torque converter model provides for a locked or unlocked torque converter clutch.

Claims

1. A driveline method, comprising:

adjusting torque of a torque source in response to a virtual torque converter impeller speed when a torque converter clutch is locked.

2. The method of claim 1, where the torque source is a driveline integrated starter/generator.

3. The method of claim 1, where the torque source is an engine.

4. The method of claim 1, where the virtual torque converter impeller speed is based on torque output of an engine determined when the torque converter clutch is unlocked.

5. The method of claim 1, where the virtual torque converter impeller speed is based on torque output of a driveline integrated starter/generator when the torque converter clutch is unlocked.

6. The method of claim 1, further comprising adjusting the torque of the torque source in response to a speed ratio of the virtual torque converter impeller speed and actual torque converter turbine speed.

7. The method of claim 1, further comprising adjusting the torque of the torque source in response to a torque ratio of a torque converter.

8. A driveline method, comprising:

operating a torque source in a speed control mode during a vehicle creep mode while a clutch of a torque converter is open; and

transitioning operating the torque source from the speed control mode to a torque control mode and locking the clutch during the vehicle creep mode in response to a vehicle operating condition.

9. The method of claim 8, further comprising adjusting torque of a torque source in response to a virtual torque converter impeller speed when a torque converter clutch is locked.

10. The method of claim 9, where the virtual torque converter impeller speed is based on operating conditions of a driveline integrated starter/generator.

11. The method of claim 8, where the virtual torque converter impeller speed is based on operating conditions of an engine.

12. The method of claim 8, further comprising adjusting torque of a torque source in response to torque converter impeller speed when a torque converter clutch is unlocked.

13. The method of claim 8, further comprising adjusting torque of the torque source in the torque control mode in response to a filtered torque.

14. The method of claim 13, where the filtered torque is based on a torque when the torque source operated in the speed control mode.

15. A driveline system, comprising:

an engine;

an electric machine;

a transmission mechanically coupled to the electric machine, the transmission including a torque converter with a torque converter clutch; and

a controller including executable instructions stored in non-transitory memory for adjusting torque of the engine or the electric machine in response to a virtual torque converter impeller speed different from an actual torque converter impeller speed.

16. The driveline system of claim 15, where the virtual torque converter speed is based on operating conditions of the engine.

17. The driveline system of claim 15, where the virtual torque converter speed is based on operating conditions of the electric machine.

18. The driveline system of claim 15, where the operating condition is a battery state of charge.

19. The driveline system of claim 15, where the virtual torque converter impeller speed is determined when the torque converter clutch is locked.

20. The driveline system of claim 15, where the torque of the engine or the electric machine is adjusted in further response to a torque converter model.