MODE CHANGE CONTROL SYSTEM FOR HYBRID VEHICLE

• US 20080275601A1
• Filed: 04/03/2008
• Published: 11/06/2008
• Est. Priority Date: 05/02/2007
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Ueno, Munetoshi, Saito, Katsuyuki, Tsukidate, Hidetoshi
• Granted Patent: US 8,688,299 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 2006/541 without reverse ratio using instead electric reversing
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/081 Speed
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2520/06 Direction of travel
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/103 Accelerator thresholds, e.g. kickdown
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 : Torque
• CPC Class Codes: B60W 2710/24 : Energy storage means
• CPC Class Codes: B60W 30/18036 : Reversing
• 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 50/0097 : Predicting future conditions
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

In a hybrid vehicle in which a mode change between an electric drive mode and a hybrid drive mode is carried out based on information concerning an operating condition and a driving status, an impairment of operability due to a change of the drive mode at a reverse travel of the vehicle is prevented. Upon a start of the reverse travel, the drive mode before the start of the reverse travel is continued at the start of the reverse travel.

Claims

1. A mode change control system of a hybrid vehicle including an engine and a motor/generator, the control system comprising:

a controller configured to select and change between an electric drive mode in which the vehicle is driven only by power of the motor/generator with the engine stopped and a hybrid drive mode in which the vehicle is driven by power of at least the engine based on information concerning an operating condition and a driving status of the vehicle; and

wherein

the controller is further configured to continue a drive mode before a start of a reverse travel at the start of the reverse travel.

2. The mode change control system according to claim 1 wherein the controller is further configured to:

judge a drive mode of a forward travel based on whether the information concerning the operating condition and the driving status of the vehicle indicates an electric drive area where the electric drive mode should be selected or a hybrid drive area where the hybrid drive mode should be selected;

temporarily judge a drive mode for the reverse travel based on the drive mode at the forward travel so that the drive mode at the forward travel is continued at the start of the reverse travel;

judge whether the information concerning the operating condition and the driving status of the vehicle at the start of the reverse travel indicates the electric drive area where the electric drive mode should be selected or the hybrid drive area where the hybrid drive mode should be selected; and

execute a final judgment to select the hybrid drive mode as the drive mode for the reverse travel even if the temporarily judged drive mode is the electric drive mode when the information concerning the operating condition and the driving status at the start of the reverse travel indicates the hybrid drive area where the hybrid drive mode should be selected; and

wherein the electric drive area for the reverse travel is greater than the electric drive area for the forward travel.

3. The mode change control system according to claim 2 wherein:

the information concerning the operating condition and the driving status is an accelerator opening of the vehicle;

the electric drive area is an area where the accelerator opening is smaller than a predetermined value; and

the hybrid drive area is an area where the accelerator opening is greater than or equal to the predetermined value.

4. The mode change control system according to claim 1 wherein the vehicle further comprises a battery configured to receive power from and to provide power to the motor/generator;

and wherein the controller is further configured to;

estimate a battery power amount to be consumed in the electric drive mode during the reverse travel; and

start the engine at the start of the reverse travel even if the drive mode before the start of the reverse travel is the electric drive mode where an estimation battery charge state obtained by subtracting the estimation battery power amount from a battery charge state at the start of the reverse travel is under a lower limit of an allowable range of the battery charge state.

5. The mode change control system according to claim 1 wherein the controller is further configured to obtain the battery charge state of the battery.

6. The mode change control system according to claim 1 wherein the information includes a usage state of the battery, a usage state of the motor/generator, and a usage state of an electric circuit connecting the motor/generator and the battery;

and wherein the controller is further configured to;

judge whether or not at least one of the usage states at the start of the reverse travel is within an allowable range where the selection of the electric drive mode is allowed;

detect an operation of a brake by a driver; and

gradually reduce a driving force of wheels to zero and start the engine when a vehicle speed is 0 and the brake operation is ON even if the drive mode before the start of the reverse travel is the electric drive mode where the at least one usage state at the start of the reverse travel is not within the allowable range.

7. The mode change control system according to claim 6 wherein the controller is further configured to:

judge whether or not the usage state at the forward travel is within an allowable range where the selection of the electric drive mode is allowed; and

wherein the allowable range used for the reverse travel is greater than the allowable range used for the forward travel.

8. The mode change control system according to claim 1 wherein the controller is further configured to:

select the hybrid drive mode as a drive mode for the reverse travel where the drive mode before the start of the reverse travel is the hybrid drive mode.

9. A mode change control system of a hybrid vehicle including an engine and a motor/generator, the control system comprising:

means for selecting and changing between an electric drive mode in which the vehicle is driven only by power of the motor/generator with the engine stopped and a hybrid drive mode in which the vehicle is driven by power of at least the engine based on information concerning an operating condition and a driving status of the vehicle; and

means for continuing a drive mode before a start of a reverse travel at the start of the reverse travel.

10. A method for changing the control system mode of a hybrid vehicle comprising:

selecting and changing between an electric device mode in which the vehicle is driven by only power of a motor/generator with the engine stopped and a hybrid drive mode in which the vehicle is driven by power of at least the engine based on information of an operating condition and a driving status of the vehicle; and

continuing a drive mode before a start of a reverse travel at the start of the reverse travel.

11. The method according to claim 10, further comprising:

judging a drive mode of a forward travel based on whether the information concerning the operating condition and the driving status of the vehicle indicates an electric drive area where the electric drive mode should be selected or a hybrid drive area where the hybrid drive mode should be selected;

temporarily judging a drive mode for the reverse travel based on the drive mode at the forward travel so that the drive mode at the forward travel is continued at the start of the reverse travel;

judging whether the information concerning the operating condition and the driving status of the vehicle at the start of the reverse travel indicates the electric drive area where the electric drive mode should be selected or the hybrid drive area where the hybrid drive mode should be selected; and

executing a final judgment to select the hybrid drive mode as the drive mode for the reverse travel even if the temporarily judged drive mode is the electric drive mode where the information concerning the operating condition and the driving status at the start of the reverse travel indicates the hybrid drive area where the hybrid drive mode should be selected; and

wherein the electric drive area for the reverse travel is greater than the electric drive area for the forward travel.

12. The method according to claim 10 wherein the vehicle further comprises a battery configured to receive power from and to provide power to the motor/generator, the method further comprising:

estimating a battery power amount to be consumed in the electric drive mode during the reverse travel; and

starting the engine at the start of the reverse travel even if the drive mode before the start of the reverse travel is the electric drive mode where an estimation battery charge state obtained by subtracting the estimation battery power amount from a battery charge state at the start of the reverse travel is under a lower limit of an allowable range of the battery charge state.

13. The method according to claim 12, further comprising:

estimating the battery charge state of the battery.

14. The method according to claim 10 wherein the information includes a usage state of the battery, a usage state of the motor/generator, and a usage state of an electric circuit connecting the motor/generator and the battery, the method further comprising:

judging whether or not at least one of the usage states at the start of the reverse travel is within an allowable range where the selection of the electric drive mode is allowed;

detecting an operation of a brake by a driver; and

gradually reducing a driving force of wheels to zero and starting the engine when a vehicle speed is 0 and the brake operation is ON even if the drive mode before the start of the reverse travel is the electric drive mode where the at least one usage state at the start of the reverse travel is not within the allowable range.

15. The method according to claim 10, further comprising:

judging whether or not a usage state at the forward travel is within an allowable range where the selection of the electric drive mode is allowed; and

wherein the allowable range used for the reverse travel is greater than the allowable range used for the forward travel.

16. The method according to claim 10, further comprising:

selecting the hybrid drive mode as a drive mode for the reverse travel where the drive mode before the start of the reverse travel is the hybrid drive mode.