Control apparatus and method for controlling a hybrid vehicle

• US 8,414,450 B2
• Filed: 02/27/2009
• Issued: 04/09/2013
• Est. Priority Date: 03/03/2008
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Ueno, Muetoshi, Saito, Masakazu
• Primary Examiner(s): Le, David D
• Assistant Examiner(s): Hansen, Colby M
• Application Number:
  US12/920,382
• Publication Number:
  US 20110165992A1
• Time in Patent Office: 1,502 Days
• Field of Search: 477/5, 477/9, 477/118, 180/65.265, 701/68
• US Class Current: 477/5
• 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 one of a plurality of driving modes as a drive mode of the hybrid vehicle, wherein the driving modes include at least;

(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;

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

keep the engine brake drive mode and 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 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.

4. 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.

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.

6. 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.

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 an engine brake drive mode when a demand for driving force ends, wherein the hybrid vehicle has at least the following driving modes available 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) the 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;

performing a coasting drive when a demand for driving force ends and while the engine brake drive mode is selected; 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 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.

12. 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.

13. 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.

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.