Methods and system for mitigating engine and motor torque disturbances of a hybrid vehicle

• US 9,802,602 B2
• Filed: 01/08/2016
• Issued: 10/31/2017
• Est. Priority Date: 01/08/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Yamazaki, Mark Steven, Thompson, Scott James, Johri, Rajit, Wang, Xiaoyong, Meyer, Jason
• Primary Examiner(s): NGUYEN, TAN QUANG
• Application Number:
  US14/991,659
• Publication Number:
  US 20170197607A1
• Time in Patent Office: 662 Days
• Field of Search: 701 22, 701 51, 701 67, 477 5, 477107
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• 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 10/02 including control of driveline clutches
• 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 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/02 Clutches
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/905 Combustion engine
• CPC Class Codes: Y10S 903/906 Motor or generator
• CPC Class Codes: Y10S 903/912 Drive line clutch

Abstract

Systems and methods for operating a transmission of a hybrid powertrain that includes a motor/generator are described. The systems and methods may improve engine starting during engine starts where little or larger driver demand torques are requested. In one example, engine torque may be commanded to a torque based on a filtered driver demand torque, the filtered driver demand torque filtered based on a position of an accelerator pedal.

Claims

1. A powertrain operating method, comprising:

during engine run-up from cranking speed to a desired speed before a driveline disconnect clutch coupled to an engine is fully closed, commanding an engine torque to a first torque bounded by a lower limit and an upper limit, the lower limit and the upper limit based on an accelerator pedal position, where the upper limit is a torque that is a maximum of a driver demand torque and a second torque that is solely a function of accelerator pedal position.

2. The method of claim 1, further comprising commanding a motor torque to the driver demand torque during the engine run-up.

3. The method of claim 1, where the lower limit is a third torque that is solely a function of accelerator pedal position and different from the second torque.

4. The method of claim 1, where the desired speed is a speed of a motor coupled to a transmission and a second side of the driveline disconnect clutch, and where the engine is coupled to a first side of the driveline disconnect clutch.

5. The method of claim 1, where the driveline disconnect clutch is fully closed when driveline disconnect clutch speed on an engine side of the driveline disconnect clutch is a same speed as driveline disconnect clutch speed on a motor side of the driveline disconnect clutch.

6. A powertrain operating method, comprising:

during engine run-up from cranking speed to a desired speed before a driveline disconnect clutch coupled to an engine is fully closed, commanding an engine torque to a first torque bounded by a lower limit and an upper limit;

commanding engine torque to a predetermined torque during closing of the driveline disconnect clutch; and

commanding engine torque to a driver demand torque including commanding the engine to a filtered driver demand torque in response to the driveline disconnect clutch being fully closed.

7. The method of claim 6, where the filtered driver demand torque includes a filter rate that is based on an accelerator pedal position.

8. The method of claim 6, further comprising commanding a motor torque to a difference between the driver demand torque and an estimated engine torque in response to the driveline disconnect clutch being fully closed.

9. The method of claim 6, where filtering the driver demand torque includes filtering the driver demand torque via a longer time constant at accelerator pedal positions less than a threshold.

10. The method of claim 9, where filtering the driver demand torque includes filtering the driver demand torque via a shorter time constant at accelerator pedal positions greater than the threshold.

11. The method of claim 6, where the predetermined torque is based on a driveline disconnect clutch torque capacity.

12. The method of claim 6, where filtering the driver demand torque includes filtering the driver demand torque via a rate limiting filter.

13. The method of claim 6, where the lower limit and the upper limit are based on an accelerator pedal position.

14. A system, comprising:

an engine;

a motor/generator;

a disconnect clutch positioned in a powertrain between the engine and the motor/generator;

a transmission coupled to the motor/generator; and

a controller including executable instructions stored in non-transitory memory for commanding an engine torque and a motor torque during engine starting to a time when motor torque is zero or less than zero and engine torque is equal to or greater than a driver demand torque, the engine torque commanded based on a rate filtered driver demand torque that reduces a rate of engine torque increase for accelerator pedal positions less than a threshold and increases the rate of engine torque increase for accelerator pedal positions greater than the threshold.

15. The system of claim 14, where the engine torque is commanded based on the rate filtered driver demand torque only after starting to close the disconnect clutch.

16. The system of claim 14, further comprising additional instructions to command motor torque to provide the driver demand torque during engine cranking and run-up to motor speed.

17. The system of claim 14, further comprising additional instructions to command motor torque to zero or less than zero in response to fully closing the disconnect clutch.

18. The system of claim 14, further comprising additional instructions to estimate engine torque based on engine speed and engine load.

19. The system of claim 18, further comprising additional instructions to adjust motor torque based on the estimate of engine torque.