CONTROL APPARATUS AND METHOD FOR CONTROLLING A HYBRID VEHICLE

• US 20110165992A1
• Filed: 02/27/2009
• Published: 07/07/2011
• Est. Priority Date: 03/03/2008
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Saito, Masakazu, Ueno, Muetoshi
• Granted Patent: US 8,414,450 B2
• Time in Patent Office: Days
• US Class Current: 477/9
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/48 Parallel 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 10/115 with planetary gears
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 30/18072 Coasting
• CPC Class Codes: B60W 30/18109 Braking
• CPC Class Codes: B60W 30/18136 Engine braking
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/123 the fuel injection being cut-off
• CPC Class Codes: Y02T 10/60 Other road transportation technologies with climate change mitigation effect
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A hybrid vehicle in which a clutch is disposed between an engine and a motor/generator is controlled to suppress frequent engagement/disengagement of the clutch in a case of a coasting drive while dragging the engine. A clutch control apparatus controls the clutch and selects any one of the following drive modes: 1) an EV drive mode where the vehicle travels by only driving force of the motor/generator with the clutch disengaged; 2) an HEV drive mode where the vehicle travels by driving force of the engine and/or the motor/generator with the clutch engaged; and 3) an engine brake drive mode in which the vehicle coasts or travels by the driving force of the motor/generator while dragging the engine where the clutch is engaged, and the fuel supply is stopped when a charge of the battery is greater than or equal to a threshold value.

Claims

1. A control apparatus of a hybrid vehicle including an engine, a motor/generator and a clutch arranged between the engine and the motor/generator and capable of connecting and disconnecting the engine and the motor/generator, the control apparatus comprising:

a controller configured;

to select at least one of the following driving modes as a drive mode of the hybrid vehicle;

(a) an EV drive mode in which the vehicle travels by only driving force of the motor/generator with the clutch disengaged; and

(b) an engine brake drive mode in which the vehicle travels while dragging the engine under a condition where the clutch is engaged and a fuel supply is stopped;

to select the engine brake drive mode and to perform a coasting drive when a demand for driving force ends; and

to keep the engine brake drive mode and to perform a driving by the driving force of the motor/generator when a new demand for driving force is made during the coasting drive in the engine brake drive mode.

2. The control apparatus according to claim 1 wherein the hybrid vehicle further includes a battery that supplies power to and receives power from the motor/generator;

and wherein;

the controller is configured to select the engine brake drive mode when an amount of charge of the battery is greater than or equal to a predetermined threshold value and the demand for driving force ends.

3. The control apparatus according to claim 1 wherein the hybrid vehicle further includes a battery that supplied power to and receives power from the motor/generator;

and wherein;

the controller is configured to select the engine brake drive mode when the amount of charge of the battery is greater than or equal to a first charge threshold value and a vehicle speed is greater than or equal to a first vehicle speed threshold value and a desired driving force is zero.

4. The control apparatus according to claim 1, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged;

and wherein the controller is further configured;

to delay a shift from the engine brake drive mode to the EV drive mode or the HEV drive mode until a duration of the engine brake drive mode exceeds a certain time.

5. The control apparatus according to claim 1, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged;

and wherein the controller is further configured;

to delay a shift from the engine brake drive mode to the EV drive mode or the HEV drive mode until a duration of the engine brake drive mode exceeds a certain time and a desired driving force becomes greater than or equal to a driving force threshold value.

6. The control apparatus according to claim 2, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged;

and wherein the controller is further configured;

to shift from the engine brake drive mode to the HEV drive mode without shifting through the EV drive mode in accordance with at least one of a vehicle speed and a desired driving force when the amount of charge of the battery is smaller than or equal to a second charge threshold value, the second charge threshold value being smaller than a first charge threshold value.

7. The control apparatus according to claim 1, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged;

and wherein the controller is further configured;

to shift from the engine brake drive mode to the HEV drive mode without shifting through the EV drive mode when a desired driving force exceeds a threshold value defined according to a vehicle speed.

8. The control apparatus according to claim 1, wherein:

the controller is configured to shift from the engine brake drive mode to the EV drive mode when the engine brake drive mode is selected and a vehicle speed lowers to a speed smaller than or equal to a second vehicle speed threshold value.

9. A method of controlling a hybrid vehicle including an engine, a motor/generator and a clutch arranged between the engine and the motor/generator and capable of connecting and disconnecting the engine and the motor/generator, the method comprising:

selecting at least one of the following driving modes as a drive mode of the hybrid vehicle;

(a) an EV drive mode in which the vehicle travels by only driving force of the motor/generator with the clutch disengaged; and

(b) an engine brake drive mode in which the vehicle travels while dragging the engine under a condition where the clutch is engaged and a fuel supply is stopped;

selecting the engine brake drive mode and performing a coasting drive when a demand for driving force ends; and

keeping the engine brake drive mode and performing a driving by the driving force of the motor/generator when a new demand for driving force is made during the coasting drive in the engine brake drive mode.

10. The method according to claim 9 wherein the hybrid vehicle further includes a battery that supplies power to and receives power from the motor/generator;

and wherein selecting the engine brake drive mode further comprises selecting the engine brake drive mode when an amount of charge of the battery is greater than or equal to a predetermined threshold value and the demand for driving force ends.

11. The method according to claim 9 wherein the hybrid vehicle further includes a battery that supplied power to and receives power from the motor/generator;

and wherein selecting the engine brake drive mode further comprises selecting the engine brake drive mode when the amount of charge of the battery is greater than or equal to a first charge threshold value and a vehicle speed is greater than or equal to a first vehicle speed threshold value and a desired driving force is zero.

12. The method according to claim 9, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged, the method further comprising:

delaying a shift from the engine brake drive mode to the EV drive mode or the HEV drive mode until a duration of the engine brake drive mode exceeds a certain time and optionally until a desired driving force becomes greater than or equal to a driving force threshold value.

13. The method according to claim 10, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged, the method further comprising:

shifting from the engine brake drive mode to the HEV drive mode without shifting through the EV drive mode in accordance with at least one of a vehicle speed and a desired driving force when the amount of charge of the battery is smaller than or equal to a second charge threshold value, the second charge threshold value being smaller than a first charge threshold value.

14. The method according to claim 9, wherein the driving modes include an HEV drive mode in which the vehicle travels by at least a driving force of the engine with the clutch engaged, the method further comprising:

shifting from the engine brake drive mode to the HEV drive mode without shifting through the EV drive mode when a desired driving force exceeds a threshold value defined according to a vehicle speed.

15. The method according to claim 9, further comprising:

shifting from the engine brake drive mode to the EV drive mode when the engine brake drive mode is selected and a vehicle speed lowers to a speed smaller than or equal to a second vehicle speed threshold value.