Method and system for shutting down an engine in a hybrid vehicle

• US 20070084653A1
• Filed: 10/18/2005
• Published: 04/19/2007
• Est. Priority Date: 10/18/2005
• Status: Active Grant

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Hughes, Douglas, Busdiecker, Matthew
• Granted Patent: US 8,210,294 B2
• Time in Patent Office: Days
• US Class Current: 180/65.310
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/421 Speed
• 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

A method is provided for shutting down an internal combustion engine in a hybrid vehicle that includes a motor and a generator operatively connected to an engine crankshaft. The method includes the steps of reducing compression in at least one engine cylinder and operating the motor or generator to influence motion of the engine crankshaft during engine shutdown to attenuate oscillations in and expedite reduction of engine crankshaft speed. A system for shutting down a hybrid vehicle internal combustion engine is also provided.

Claims

1. A method for shutting down an internal combustion engine in a hybrid vehicle that includes at least one of a motor and a generator operatively connected to an engine crankshaft, the method comprising the steps of:

reducing compression in at least one engine cylinder; and

operating the motor or the generator to influence motion of the engine crankshaft during engine shutdown to attenuate oscillations in and expedite reduction of engine crankshaft speed.

2. The method of claim 1, wherein the reducing step further includes opening at least one engine valve.

3. The method of claim 1, wherein the reducing step further includes reducing compression in at least one cylinder until compression is substantially eliminated.

4. The method of claim 1, wherein the motor and the generator are integrally packaged as a motor-generator.

5. The method of claim 1, wherein the operating step includes operating the motor or the generator to apply a predetermined torque to the engine crankshaft or a target torque profile that varies with respect to time.

6. The method of claim 5, wherein the torque profile is substantially synchronized with the engine crankshaft speed during engine shutdown.

7. The method of claim 1, wherein the operating step includes operating the motor or the generator at a predetermined speed or according to a target speed profile that varies with respect to time.

8. The method of claim 7, wherein the predetermined speed is approximately zero revolutions per minute.

9. The method of claim 8, wherein the operating step includes alternatively operating the motor and the generator to actively dampen oscillations in engine crankshaft speed during engine shutdown.

10. The method of claim 1, wherein the hybrid powertrain system further includes a clutch between the engine and the motor, and the method further includes the step of activating the clutch to connect the motor to the engine prior to the operating step.

11. A method for shutting down an internal combustion engine in a hybrid vehicle that includes a motor and a generator operatively connected to an engine crankshaft, the method comprising the steps of:

reducing compression in at least one engine cylinder; and

operating the generator to remove energy from the engine crankshaft during engine shutdown, wherein the operating step includes operating the generator to apply a predetermined torque load to the engine crankshaft or a target torque load profile that varies with respect to time, or operating the generator at a predetermined speed or according to a target speed profile that varies with respect to time.

12. The method of claim 11, wherein the motor and generator are integrally packaged as a motor-generator.

13. A system for shutting down a hybrid vehicle internal combustion engine that includes at least one engine cylinder and a crankshaft, the system comprising:

an engine cylinder compression-reducing device;

at least one of a motor and a generator operatively connected to the engine crankshaft and adapted to influence motion of the engine crankshaft during engine shutdown; and

a controller configured to selectively operate the compression-reducing device to reduce compression in at least one engine cylinder and to selectively operate the motor or the generator to influence motion of the engine crankshaft during engine shutdown.

14. The system of claim 13, wherein the reducing step further includes opening at least one engine valve.

15. The system of claim 13, wherein the controller is configured to reduce compression in at least one cylinder until compression is substantially eliminated.

16. The system of claim 13, wherein the motor and the generator are integrally packaged as a motor-generator.

17. The system of claim 13, wherein the controller is configured to operate the motor or the generator to apply a predetermined torque to the engine crankshaft or a target torque profile that varies with respect to time.

18. The system of claim 17, wherein the torque load profile is substantially synchronized with the engine crankshaft speed during engine shutdown.

19. The system of claim 13, wherein the controller is configured to operate the motor or the generator at a predetermined speed or according to a target speed profile that varies with respect to time.

20. The system of claim 19, wherein the predetermined speed is approximately zero revolutions per minute.

21. The system of claim 13, wherein the controller is configured to selectively operate the motor or the generator in a closed-loop manner.

22. The system of claim 13, wherein the controller is configured to alternatively operate the motor and the generator to actively dampen oscillations in engine crankshaft speed during engine shutdown.

23. The system of claim 13, wherein the hybrid powertrain system further includes a clutch between the engine and the motor, and wherein the controller is configured to activate the clutch to connect the motor to the engine prior to the operating the motor.