MODE CHANGEOVER CONTROL DEVICE FOR A HYBRID VEHICLE

• US 20080154455A1
• Filed: 12/18/2007
• Published: 06/26/2008
• Est. Priority Date: 12/26/2006
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Saito, Katsuyuki, Hidaka, Terumasa, Ueno, Munetoshi
• Granted Patent: US 8,060,266 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 6/48 Parallel type
• 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 2200/26 Rail vehicles
• 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 2240/425 Temperature
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 2260/26 Transition between different drive modes
• CPC Class Codes: B60L 2270/145 Structure borne vibrations
• 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: 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 2050/0083 : Setting, resetting, calibration
• CPC Class Codes: B60W 2510/0291 : Clutch temperature
• CPC Class Codes: B60W 2510/081 : Speed
• CPC Class Codes: B60W 2510/087 : Temperature
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 30/1843 : Overheating of driveline components B60W30/186 takes precedence
• CPC Class Codes: B60W 30/186 : excessive wear or burn out of friction elements, e.g. clutches
• CPC Class Codes: B60W 30/192 : Mitigating problems related to power-up or power-down of the driveline, e.g. start-up of a cold engine
• CPC Class Codes: B60W 40/10 : related to vehicle motion
• 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

A mode changeover control device for a hybrid vehicle includes an engine, a motor/generator and at least one driving wheel. A changeover between an electric drive mode using only the electric motor to power the at least one driving wheel and a hybrid drive mode using both the engine and the electric motor to power the at least one driving wheel is controlled. The drive mode is changed from the hybrid drive mode to the electric drive mode if the accelerator opening is less than a first threshold level, and the drive mode is changed from the electric drive mode to the hybrid drive mode if the accelerator opening is greater than a second threshold level. A hysteresis value is defined between the first threshold level and the second threshold level, and the hysteresis value is changed based on a vehicle operating state.

Claims

1. A control device for a hybrid vehicle including an engine, a motor/generator, and at least one driving wheel, the hybrid vehicle operable in an electric drive mode in which the vehicle is powered only by the motor/generator and a hybrid drive mode in which the vehicle is powered by both the engine and the motor/generator, the control device comprising:

a controller configured to;

set a first threshold level of an accelerator opening;

set a second threshold level of the accelerator opening, wherein a hysteresis value is defined between the first threshold level and the second threshold level;

change the hysteresis value based on at least one of a vehicle operating state and a driving environment;

receive a signal corresponding to the accelerator opening;

initiate a changeover from the hybrid drive mode to the electric drive mode if the accelerator opening is less than the first threshold level; and

initiate a changeover from the electric drive mode to the hybrid drive mode if the accelerator opening is greater than the second threshold value.

2. The control device according to claim 1 wherein the at least one of the vehicle operating state and the driving environment includes a vehicle speed;

and wherein the controller is further configured to change the hysteresis value by increasing the hysteresis value as the vehicle speed decreases.

3. The control device according to claim 2 wherein the controller is further configured to change the hysteresis value by adjusting the first threshold level based on the at least one of the vehicle operating state and the driving environment.

4. The control device according to claim 3 wherein the second threshold level remains unchanged in response to a change in the hysteresis value.

5. The control device according to claim 1 wherein the controller is further configured to change the hysteresis value by adjusting the first threshold level based on the at least one of the vehicle operating state and the driving environment.

6. The control device according to claim 5 wherein the second threshold level remains unchanged in response to a change in the hysteresis value.

7. The control device according to claim 1 wherein the controller is further configured to change the hysteresis value by decreasing the first threshold level with vehicle speed and maintaining the second threshold level at a constant value regardless of the vehicle speed.

8. The control device according to claim 7 wherein the hybrid vehicle further comprises a first clutch disposed between the engine and the motor/generator to change a torque transmission capacity between the engine and the motor/generator and a second clutch disposed between the motor/generator and the at least one driving wheel to change a torque transmission capacity between the motor/generator and the at least one driving wheel;

and wherein the control system further comprises;

the controller configured to initiate the changeover to the electric drive mode by signaling disengagement the first clutch and engagement of the second clutch and to initiate the changeover to the hybrid drive mode by signaling engagement of the first clutch and the second clutch; and

wherein

the controller configured to change the hysteresis value by increasing the hysteresis value as the temperature of the second clutch increases.

9. The control device according to claim 1 wherein the controller is configured to change the hysteresis value by increasing the hysteresis value as the temperature of an electric drive control system including the motor/generator increases.

10. A control device of a hybrid vehicle including an engine, a motor/generator, and at least one driving wheel, the hybrid vehicle operable in an electric drive mode in which the vehicle is powered only by the motor/generator and a hybrid drive mode in which the vehicle is powered by both the engine and the motor/generator, the control system comprising:

means for setting a first threshold level of an accelerator opening;

means for setting a second threshold level of the accelerator opening, wherein a hysteresis value is defined between the first threshold level and the second threshold level;

means for changing the hysteresis value based on at least one of a vehicle operating state and a driving environment;

means for receiving a signal corresponding to the accelerator opening;

means for initiating a changeover from the hybrid drive mode to the electric drive mode if the accelerator opening is less than the first threshold level; and

means for initiating a changeover from the electric drive mode to the hybrid drive mode if the accelerator opening is greater than the second threshold value.

11. A method for controlling a hybrid vehicle including an engine, a motor/generator, and at least one driving wheel, the hybrid vehicle operable in an electric drive mode in which the vehicle is powered only by the motor/generator and a hybrid drive mode in which the vehicle is powered by both the engine and the motor/generator, the method comprising:

setting a first threshold level of an accelerator opening;

setting a second threshold level of the accelerator opening, wherein a hysteresis value is defined between the first threshold level and the second threshold level;

changing the hysteresis value based on at least one of a vehicle operating state and a driving environment;

receiving a signal corresponding to the accelerator opening;

initiating a changeover from the hybrid drive mode to the electric drive mode if the accelerator opening is less than the first threshold level; and

initiating a changeover from the electric drive mode to the hybrid drive mode if the accelerator opening is greater than the second threshold value.

12. The method according to claim 11 wherein the at least one of the vehicle operating state and the driving environment includes a vehicle speed;

and wherein changing the hysteresis value further comprises increasing the hysteresis value as the vehicle speed decreases.

13. The method according to claim 12 wherein changing the hysteresis value further comprises:

increasing the hysteresis value as the temperature of an electric drive control system including the motor/generator increases.

14. The method according to claim 11 wherein changing the hysteresis value further comprises:

adjusting the first threshold level based on the at least one of the vehicle operating state and the driving environment.

15. The method according to claim 14 wherein changing the hysteresis value further comprises:

increasing the hysteresis value as the temperature of an electric drive control system including the motor/generator increases.

16. The method according to claim 11 wherein changing the hysteresis value further comprises:

decreasing the first threshold level with vehicle speed based on a total amount of a change to the hysteresis value; and

maintaining the second threshold level unchanged in response to the change to the hysteresis value.

17. The method according to claim 16 wherein the hybrid vehicle further comprises a first clutch disposed between the engine and the motor/generator to change a torque transmission capacity between the engine and the motor/generator and a second clutch disposed between the motor/generator and the at least one driving wheel to change a torque transmission capacity between the motor/generator and the at least one driving wheel, the method further comprising:

initiating the changeover to the electric drive mode by signaling disengagement the first clutch and engagement of the second clutch; and

initiating the changeover to the hybrid drive mode by signaling engagement of the first clutch and the second clutch; and

wherein changing the hysteresis value by increasing the hysteresis value as the temperature of the second clutch increases.

18. The method according to claim 11 wherein changing the hysteresis value further comprises:

increasing the hysteresis value as the temperature of an electric drive control system including the motor/generator increases.