Smoothing hybrid vehicle engine shutdown

• US 9,227,630 B2
• Filed: 02/17/2014
• Issued: 01/05/2016
• Est. Priority Date: 02/17/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: McGee, Ryan A., Johri, Rajit, Liang, Wei, Yamazaki, Mark S., Wang, Xiaoyong, Kuang, Ming L.
• Primary Examiner(s): Hlavka, David J
• Application Number:
  US14/181,905
• Publication Number:
  US 20150232086A1
• Time in Patent Office: 687 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 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• 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 20/40 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 2030/206 related or induced by the engine
• CPC Class Codes: B60W 2710/027 Clutch torque
• CPC Class Codes: B60W 2710/0661 Speed change rate
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 15/08 the gearing being of friction type
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

A method of smoothing hybrid vehicle engine shutdown. A powered and rotating electric machine is used to slow deceleration of an unpowered and rotating engine by transferring torque through a clutch from the machine to the unpowered engine. Prior to the machine being powered, torque may be transferred through the clutch from the unpowered and rotating engine to the unpowered machine to accelerate passage of the engine through a resonance frequency.

Claims

1. A method of smoothing hybrid vehicle engine shutdown comprising:

powering an engine and rotating an electric machine while a clutch between the engine and machine is disengaged;

unpowering the engine while the machine remains rotating with the clutch disengaged;

controlling deceleration of the unpowered engine by controlling the clutch to transfer torque from the rotating machine to the unpowered engine and decreasing rotation of the machine.

2. The method of claim 1 wherein rotation of the machine is decreased more slowly than a natural deceleration rate of the engine.

3. The method of claim 1 wherein rotation of the powered machine is decreased to zero while the clutch is transferring torque from the machine to the unpowered engine.

4. The method of claim 1 wherein, after a period of transferring torque from the rotating machine to the unpowered engine to decelerate the engine, the clutch is disengaged prior to the engine completely stopping rotation.

5. The method of claim 1 wherein the machine is an electric motor.

6. The method of claim 1 wherein the machine is a belted integrated starter generator.

7. The method of claim 1 wherein, before unpowering the engine, the engine is slowed to an idle speed.

8. A method of smoothing hybrid vehicle engine shutdown comprising:

powering and rotating an engine while a clutch between the engine and an unpowered, electric machine is disengaged;

while the engine is powered and rotating, and the machine unpowered, unpowering the engine;

rotating the unpowered machine by controlling the clutch to transfer torque from the unpowered and rotating engine to the machine;

when rotation of the engine and machine are each non-zero and within a predetermined speed range, powering the rotating machine; and

controlling deceleration of the unpowered engine by decreasing rotation of the powered and rotating machine and controlling the clutch to transfer torque from the powered and rotating machine to the unpowered engine.

9. The method of claim 8 wherein rotation of the powered machine is decreased more slowly than a natural deceleration rate of the engine.

10. The method of claim 8 wherein rotation of the powered machine is decreased to zero while the clutch is controlled to transfer torque from the machine to the unpowered engine.

11. The method of claim 8 wherein, after a period of transferring torque from the rotating machine to the unpowered engine to decelerate the engine, the clutch is disengaged prior to the engine completely stopping rotation.

12. The method of claim 8 wherein the machine is an electric motor.

13. The method of claim 12 wherein transferring torque from the engine to the machine generates an electrical current stored in a battery.

14. The method of claim 8 wherein, during transfer of torque from the unpowered engine to the unpowered machine, the engine is rotating at a greater speed than the machine at a time when the clutch is initially controlled to transfer torque.

15. The method of claim 14 wherein the machine is an electric motor.

16. The method of claim 8 wherein the machine is a belted integrated starter generator.

17. The method of claim 8 wherein, before unpowering the engine, the engine is slowed to idle speed.

18. A method of smoothing hybrid vehicle engine shutdown comprising:

powering an engine while a clutch interposed between the engine and a machine is disengaged;

unpowering the engine while the clutch remains disengaged;

powering the machine and controlling the clutch to transfer torque from the rotating machine to the unpowered engine to control deceleration of the unpowered engine while decreasing rotation of the machine.

19. The method of claim 18 wherein rotation of the powered machine is decreased to zero while the clutch is controlled to transfer torque from the machine to the unpowered engine.

20. The method of claim 18 wherein, after a period of transferring torque from the rotating machine to the unpowered engine to decelerate the engine, the clutch is disengaged prior to the engine completely stopping rotation.