Methods and systems for restarting an engine

• US 9,393,950 B2
• Filed: 07/22/2013
• Issued: 07/19/2016
• Est. Priority Date: 07/22/2013
• 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, Connolly, Francis Thomas, Doering, Jeffrey Allen, Wang, Xiaoyong, Johri, Rajit
• Primary Examiner(s): Shaawat, Mussa A
• Application Number:
  US13/947,947
• Publication Number:
  US 20150025724A1
• Time in Patent Office: 1,093 Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/48 Parallel 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 10/08 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 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/021 Clutch engagement state
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/184 Preventing damage resulting from overload or excessive wear of the driveline
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

Systems and methods for improving operation of a hybrid vehicle are presented. In one example, torque output of a motor is controlled to include a reserve torque for starting an engine that may be selectively coupled to the motor. Additionally, the motor torque compensates for disconnect clutch closing.

Claims

1. A method for operating a hybrid driveline, comprising:

in response to an increase in a driver demand torque, supplying a portion of the increase in the driver demand torque to the hybrid driveline before starting an engine, where supplying the portion of the increased driver demand torque includes increasing torque to vehicle wheels, and where increasing torque to vehicle wheels includes increasing motor torque output to the hybrid driveline up to a first driver demand torque limit;

starting the engine in response to the driver demand torque exceeding the first driver demand torque limit;

supplying a remainder of the increase in driver demand torque to the hybrid driveline after starting the engine in response to speed of the engine being within a predetermined speed of a speed of a motor;

increasing the driver demand torque limit to a second torque limit in response to a speed of the engine being within a predetermined speed of the motor; and

partially closing a driveline disconnect clutch during starting the engine.

2. The method of claim 1, where the first torque limit is based on available torque from the motor minus engine starting torque.

3. The method of claim 1, where the first torque limit is a driver demand torque limit.

4. The method of claim 2, where the available torque from the motor varies with motor temperature and battery state of charge.

5. A method for operating a hybrid driveline, comprising:

in response an increase in driver demand torque, supplying torque to the hybrid driveline up to a first driver demand torque limit, the first driver demand torque limit based on a maximum torque from a motor minus engine starting torque;

starting an engine via the motor in response to the driver demand torque exceeding the first driver demand torque limit; and

supplying torque to the hybrid driveline greater than the first driver demand torque limit in response to a speed of the engine being within a predetermined speed of a speed of the motor.

6. The method of claim 5, further comprising partially closing a driveline disconnect clutch to start the engine.

7. The method of claim 6, further comprising opening the driveline disconnect clutch in response to starting the engine.

8. The method of claim 7, further comprising closing the disconnect clutch in response to the speed of the engine being within the predetermined speed of a speed of the motor.

9. The method of claim 8, further comprising increasing motor torque to the maximum torque from the motor during closing the disconnect clutch.

10. The method of claim 5, where torque supplied to the hybrid driveline is provided via the motor before starting the engine.

11. The method of claim 5, further comprising supplying the driver demand torque after starting the engine.

12. A hybrid vehicle system, comprising:

an engine;

a motor selectively coupled to the engine via a driveline disconnect clutch; and

a controller including non-transitory instructions executable to start the engine in response to a desired driver demand torque being within a threshold torque of a first driver demand torque limit, the first driver demand torque limit based on maximum torque from the motor minus engine starting torque, and additional instructions to increase the first driver demand torque limit after the driveline disconnect clutch is fully closed.

13. The hybrid vehicle system of claim 12, further comprising additional instructions to partially close the driveline disconnect clutch to start the engine.

14. The hybrid vehicle system of claim 12, where the driveline disconnect clutch is positioned between the engine and the motor and further comprising additional instructions to fully close the driveline disconnect clutch after the engine is started.

15. The hybrid vehicle system of claim 14, further comprising additional instructions to increase torque output from the motor while fully closing the driveline disconnect clutch.

16. The hybrid vehicle system of claim 12, further comprising additional instructions to determine a second torque limit, the second torque limit an amount of available torque the motor has the capacity to produce.