Vehicle driving force control apparatus

• US 20040043862A1
• Filed: 08/15/2003
• Published: 03/04/2004
• Est. Priority Date: 09/04/2002
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kadota, Keiji, Iwata, Yasuaki, Kamata, Tatsuya, Nakamura, Kimitaka
• Granted Patent: US 6,969,337 B2
• Time in Patent Office: Days
• US Class Current: 477/8
• CPC Class Codes: B60K 6/44 Series-parallel type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• 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 2510/0208 Clutch engagement state, e.g. engaged or disengaged
• CPC Class Codes: B60W 2510/083 Torque
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• 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 vehicle driving force control apparatus is provided for a vehicle having an electric motor transmitting a drive torque to a first wheel, and a clutch installed between the electric motor and the first wheel. The vehicle driving force control apparatus basically comprises a clutch control section and a motor control section. The clutch control section is configured to control engagement and release of the clutch. The motor control section is configured to control a motor response characteristic by increasing the motor response characteristic of the motor from a first response characteristic to a second response characteristic when the clutch control section releases the clutch. Preferably, the vehicle driving force control apparatus is configured to cancel insufficient torque generation due to undershoot armature current when controlling armature current of an electric motor and transmitting torque to subordinate drive wheels.

Claims

1. A vehicle driving force control apparatus of a vehicle having an electric motor transmitting a drive torque to a first wheel, and a clutch installed between the electric motor and the first wheel, the vehicle driving force control apparatus comprising:

a clutch control section configured to control engagement and release of the clutch; and

a motor control section configured to control a motor response characteristic by increasing the motor response characteristic of the motor from a first response characteristic to a second response characteristic when the clutch control section releases the clutch.

2. The vehicle driving force control apparatus as recited in claim 1, wherein

the motor control section is configured to control at least one of an armature current of the electric motor and a field current of the electric motor such that the motor response characteristic of the motor increases from the first response characteristic to the second response characteristic when the clutch control section releases the clutch.

3. The vehicle driving force control apparatus as recited in claim 1, further comprising

a main driving source is configured to drive a second wheel that is not driven by the electric motor.

4. The vehicle driving force control apparatus as recited in claim 3, further comprising:

a mode selection section configured to select one of a multi-wheel drive mode in which both the first wheel and second wheel are driven and a non-all wheel drive mode in which the first wheel is not driven by the electric motor.

5. The vehicle driving force control apparatus as recited in claim 3, wherein

the motor control section is configured to control at least one of an armature current of the electric motor and a field current of the electric motor such that the motor response characteristic of the motor increases from the first response characteristic to the second response characteristic when the clutch control section releases the clutch.

6. The vehicle driving force control apparatus as recited in claim 5, wherein

the motor control section further configured to control the armature current of the electric motor by controlling a field current of a generator of the vehicle, the generator being driven by the main driving source to supply the armature current to the electric motor.

7. The vehicle driving force control apparatus as recited in claim 6, wherein

the motor control section further including:

an armature current detection section configured to detect the armature current of the electric motor;

an armature current target value computation section configured to compute an armature current target value of the electric motor; and

a generator output control section configured to multiply a control gain by a deviation between the armature current target value and the armature current to create a field control signal that is outputted to the generator; and

the motor control section is further configured to change the control gain from a normal value for the clutch engaged mode to a high response value larger than normal responsive value, when the clutch engaged mode is switched to the clutch disengaged mode.

8. The vehicle driving force control apparatus as recited in claim 1, further comprising:

a surplus torque computing section configured to compute a surplus torque of a second wheel driven by a main driving source independent of the clutch being engaged; and

an electric motor torque computing section configured to compute an electric motor torque based on the surplus torque; and

a mode selection section configured to select a multi-wheel drive mode when the electric motor torque is higher than a predetermined threshold value, and select a non-all wheel drive mode when the electric motor torque is equal to or lower than the predetermined threshold value.

9. The vehicle driving force control apparatus as recited in claim 8, wherein

the motor control section being further configured to start increasing the motor response characteristic of the motor from the first response characteristic to the second response characteristic when the electric motor torque is equal to or lower than the predetermined threshold value.

10. The vehicle driving force control apparatus as recited in claim 8, wherein

the main driving source is configured to drive a generator that supplies power to the electric motor.

11. The vehicle driving force control apparatus as recited in claim 10, wherein

the main driving source is an internal combustion engine.

12. The vehicle driving force control apparatus as recited in claim 10, further comprising:

a mode selection section configured to select one of a multi-wheel drive mode in which both the first wheel and second wheel are driven and a non-all wheel drive mode in which the first wheel is not driven by the electric motor.

13. The vehicle driving force control apparatus as recited in claim 12, wherein

the motor control section is configured to control at least one of an armature current of the electric motor and a field current of the electric motor such that the motor response characteristic of the motor increases from the first response characteristic to the second response characteristic when the clutch control section releases the clutch.

14. The vehicle driving force control apparatus as recited in claim 12, wherein

the motor control section further configured to control the armature current of the electric motor by controlling a field current of a generator of the vehicle, the generator being driven by the main driving source to supply the armature current to the electric motor.

15. The vehicle driving force control apparatus as recited in claim 14, wherein

the motor control section further including:

an armature current detection section configured to detect the armature current of the electric motor;

an armature current target value computation section configured to compute an armature current target value of the electric motor; and

a generator output control section configured to multiply a control gain by a deviation between the armature current target value and the armature current to create a field control signal that is outputted to the generator; and

the motor control section is further configured to change the control gain from a normal value for a clutch engaged mode to a high response value larger than normal responsive value, when the clutch engaged mode is switched to a clutch disengaged mode.

16. The vehicle driving force control apparatus as recited in claim 15, further comprising:

a surplus torque computing section configured to compute a surplus torque of a second wheel driven by a main driving source independent of the clutch being engaged; and

an electric motor torque computing section configured to compute an electric motor torque based on the surplus torque; and

the mode selection section being configured to select the multi-wheel drive mode when the electric motor torque is higher than a predetermined threshold value, and select the non-all wheel drive mode when the electric motor torque is equal to or lower than the predetermined threshold value.

17. The vehicle driving force control apparatus as recited in claim 15, wherein

the mode selection section includes a switch to manually select one of the multi-wheel drive mode and the non-all wheel drive mode.

18. A vehicle driving force control apparatus of a vehicle having an electric motor transmitting a drive torque to a first wheel, and a clutch installed between the electric motor and the first wheel, the vehicle driving force control apparatus comprising:

clutch control means for controlling engagement and release of the clutch ; and

motor control means for controlling a motor response characteristic by increasing the motor response characteristic of the motor from a first response characteristic to a second response characteristic when the clutch control means releases the clutch.

19. A method of controlling a vehicle having an electric motor transmitting a drive torque to a first wheel, and a clutch installed between the electric motor and the first wheel, the method comprising:

releasing the clutch when a clutch disengaged mode is determined; and

controlling a motor response characteristic by increasing the motor response characteristic of the motor from a first response characteristic to a second response characteristic when the clutch is being released.