Engine starting control device for a hybrid vehicle

• US 20070056783A1
• Filed: 09/07/2006
• Published: 03/15/2007
• Est. Priority Date: 09/08/2005
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Joe, Shinichiro, Okuda, Tadashi
• Granted Patent: US 7,766,107 B2
• Time in Patent Office: Days
• US Class Current: 180/65.265
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 2250/24 by lever actuation
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2260/26 Transition between different drive modes
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• 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 10/10 : including control of change-speed gearings
• CPC Class Codes: B60W 10/115 : with planetary gears
• 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 20/30 : Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• 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: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

An engine of a hybrid vehicle is lift started by reducing a rotational speed of a motor/generator of the hybrid vehicle by adjusting a gearshift ratio of a transmission coupled to the motor/generator, and engaging a clutch to couple the engine, while in a stopped state, to the rotating motor/generator for imparting the rotation to the engine.

Claims

1. A drive device for a hybrid vehicle, comprising:

an engine;

a motor/generator;

a first clutch disposed between the engine and the motor/generator having an adjustable torque capacity;

a transmission disposed between the motor/generator and drive wheels of the hybrid vehicle that can change a gearshift ratio continuously or in steps; and

a control system that can control the engine, the motor/generator, the first clutch, and the transmission;

wherein the control system comprises a controller adapted to engage the first clutch from a released state and lift-start the engine when there is a request to switch to a hybrid operation mode from an electric operation mode; and

wherein lift-starting the engine, performed according to the controller, comprises reducing a transmission input rotation speed by controlling a gearshift ratio of the transmission and, engaging the first clutch.

2. The drive device for a hybrid vehicle according to claim 1, wherein lift-starting of the engine, performed according to the controller, reduces the transmission input rotation speed to within a range that is the same or more than a rotation speed that is possible to start the engine.

3. The drive device for a hybrid vehicle according to claim 1, wherein the controller upshifts the transmission and then completes the engagement of the first clutch while operating in the electric operation mode.

4. The drive device for a hybrid vehicle according to claim 3, wherein the controller raises a torque of the motor/generator in accordance with the upshift.

5. The drive device for a hybrid vehicle according to claim 1, wherein the controller compensates for a drag torque of the first clutch using the motor/generator when lift-starting the engine.

6. The drive device for a hybrid vehicle according to claim 1, wherein the controller further comprises a shift map showing a relationship between a gear shift and an operating state of the vehicle in which an upshift line and a downshift line, when a target mode is the electric operation mode, are set more toward the high vehicle speed side than the upshift line and downshift line for when the target mode is the hybrid operation mode in relation to the shift map.

7. The drive device for a hybrid vehicle according to claim 1, wherein the drive device for the hybrid vehicle comprises a second clutch disposed between the motor/generator and the transmission that can change a transfer torque capacity.

8. The drive device for a hybrid vehicle according to claim 1, wherein the drive device for the hybrid vehicle comprises a second clutch disposed between the transmission and drive wheels of the hybrid vehicle that can change a transfer torque capacity.

9. A drive device for a hybrid vehicle, comprising:

an engine;

a motor/generator;

a first clutch disposed between the engine and the motor/generator having an adjustable torque capacity;

a transmission disposed between the motor/generator and drive wheels of the hybrid vehicle that can change a gearshift ratio continuously or in steps; and

a control system that can control the engine, the motor/generator, the first clutch, and the transmission;

wherein the control system comprises a controller adapted to engage the first clutch from a released state and lift-start the engine when there is a gear shift request and when there is a request to switch to a hybrid operation mode from an electric operation mode; and

wherein lift-starting the engine, performed according to the controller, comprises;

engaging the first clutch before a gear shift when a transmission input rotation speed before the gear shift is lower than the transmission input rotation speed after the gear shift; and

engaging the first clutch after the gear shift when the transmission input rotation speed before the gear shift is higher than the transmission input rotation speed after the gear shift.

10. The drive device for a hybrid vehicle according to claim 9, wherein the controller completes an upshift of the transmission in conjunction with an upshift request while operating in the electric operation mode, and then engages the first clutch and lift-starts the engine a drag torque of the first clutch.

11. The drive device for a hybrid vehicle according to claim 10, wherein lift-starting the engine, performed according to the controller, upshifts so that the transmission input rotation speed is in a range that is the same or more than the rotation speed that is possible to start the engine.

12. The drive device for a hybrid vehicle according to claim 10, wherein the controller raises a torque of the motor/generator in accordance with the upshift.

13. The drive device for a hybrid vehicle according to claim 9, wherein the controller completes the lift-start of the engine while using a drag torque of the first clutch in conjunction with a downshift request while operating in the electric operation mode, and then starts the downshift of the transmission.

14. The drive device for a hybrid vehicle according to claim 9, wherein the controller compensates for a drag torque of the first clutch by using the motor/generator when lift-starting the engine.

15. The drive device for a hybrid vehicle according to claim 9, wherein the controller further comprises a shift map showing a relationship between a gear shift and an operating state of the vehicle in which an upshift line and a downshift line for when a target mode is the electric operation mode are set more toward a high vehicle speed side than the upshift line and downshift line for when the target mode is the hybrid operation mode in relation to the shift map.

16. The drive device for a hybrid vehicle according to claim 9, wherein the drive device for the hybrid vehicle comprises a second clutch disposed between the motor/generator and the transmission that can change a transfer torque capacity.

17. The drive device for a hybrid vehicle according to claim 9, wherein the drive device for the hybrid vehicle comprises a second clutch disposed between the transmission and drive wheels of the hybrid vehicle that can change a transfer torque capacity.

18. A method of lift starting an engine of a hybrid vehicle, comprising:

when there is a gear shift request, reducing a rotational speed of a motor/generator of the hybrid vehicle by adjusting a gearshift ratio of a transmission coupled to the motor/generator; and

engaging a clutch to couple the engine, while in a stopped state, to the rotating motor/generator for imparting the rotation to the engine.

19. The method of claim 18, wherein reducing the rotational speed of the motor/generator comprises reducing the rotational speed of the motor/generator to about a rotational speed that is just possible to start the engine.

20. The method of claim 18, wherein reducing the rotational speed of the motor/generator is in response to a request to switch to a hybrid operation mode from an electric operation mode.

21. The method of claim 18, wherein adjusting a gearshift ratio of the transmission comprises upshifting the transmission while the hybrid vehicle is operating in an electric operation mode.

22. The method of claim 21, further comprising raising a torque of the motor/generator in accordance with a decrease in a torque transfer ratio in the transmission that accompanies upshifting the transmission.

23. The method of claim 18, further comprising downshifting the transmission after engaging the clutch.