Control device for hybrid four-wheel-drive vehicle and hybrid four-wheel-drive vehicle

• US 20050211489A1
• Filed: 08/10/2004
• Published: 09/29/2005
• Est. Priority Date: 03/24/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kowatari, Takehiko, Yamamoto, Tatsuyuki
• Granted Patent: US 7,114,589 B2
• Time in Patent Office: Days
• US Class Current: 180/243
• CPC Class Codes: B60K 23/0808 for varying torque distribution between driven axles, e.g. by transfer clutch
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• 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 2240/423 Torque
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2510/20 Steering systems
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2520/263 Slip values between front and rear axle
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A control device controls a hybrid-four-wheel-driven vehicle wherein one of the front-wheel pair and the rear-wheel pair is an engine-driven-wheel pair which is driven by an engine, and the other pair is an electric-motor-driven-wheel pair which is driven by an electric motor. In the event of slipping of the engine-driven wheels, the system increases the engine output so as to increase the driving force of the electric-motor-driven wheels for increasing the total driving force mad up of the engine-driven-wheel driving force and the electric-motor-driven-wheel driving force, thereby improving acceleration performance, unlike conventional techniques. This provides a control device for suppressing deterioration in acceleration performance of the vehicle in a case of slipping of engine-driven wheels during acceleration.

Claims

1. A control device for controlling a hybrid-four-wheel-driven vehicle wherein one of the front-wheel pair and the rear-wheel pair is an engine-driven-wheel pair which is driven by an engine, and the other pair is an electric-motor-driven-wheel pair which is driven by an electric motor connected to a generator driven by said engine, said control device comprising:

slipping detecting means for detecting slipping of said engine-driven wheels; and

output control means for increasing the output of said engine corresponding to the increased output of said electric motor.

2. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 1, wherein said slipping detecting means for said engine-driven wheels are started at the time of receiving a request for acceleration of the vehicle.

3. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 1, wherein said slipping detecting means detect slipping in the event that the rotational speed of said engine-driven wheels exceeds the rotational speed of said electric-motor-driven wheels.

4. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 1, wherein said slipping detecting means detect slipping in the event that the speed of said engine-driven wheels exceeds the driving speed of the vehicle.

5. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 1, wherein said slipping detecting means detect slipping in the event that the slippage, which is the difference in rotational speed between said engine-driven wheels and said electric-motor-driven wheels, divided by the driving speed of the vehicle, is equal to or greater than a predetermined value.

6. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 1, wherein said output control means further comprise:

means for computing the present electric-motor output based upon an input current and a field-coil current of said electric motor;

means for computing target acceleration driving force corresponding to an input acceleration request;

means for obtaining target electric-motor output based upon said present electric-motor output and said target acceleration driving force;

means for obtaining target engine output required for achieving said target electric-motor output; and

means for controlling output of said engine and output of said electric motor according to said target engine output and said target electric-motor output.

7. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 1, wherein said output control means further comprise:

effective-driving-force history computation means for obtaining history data of the effective driving force of said electric-motor driving wheels corresponding to the last slippage data for a predetermined past period; and

maximum-effective-driving-force computation means for computing the maximum value of the effective driving force of said electric-motor-driven wheels based upon said history data,

wherein the output of said electric motor is increased in a range determined by the maximum value of the effective driving force of said electric-motor-driven wheels.

13. A hybrid-four-wheel-driven vehicle including the control device according to any one of claims 1 through 12.

8. A control device for controlling a hybrid-four-wheel-driven vehicle wherein one of the front-wheel pair and the rear-wheel pair is engine-driven-wheel pair which is driven by an engine, and the other pair is an electric-motor-driven-wheel pair which is driven by an electric motor, comprising:

slipping detecting means for detecting slipping of said engine-driven wheels;

first output control means for reducing the output of the engine and reducing the output of the electric motor corresponding to the reduction of engine output when the slipping detecting means detect slipping;

second output control means for increasing the output of the electric motor and increasing the output of the engine corresponding to the increase of electric-motor output when the slipping detecting means detect slipping; and

switching means for making switching between said first output control means and said second output control means.

9. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 8, wherein said switching means comprise a switch.

10. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 9, wherein said switching means predict total effective driving forces according to said first output control means and said second output control means, each of which include the effective driving force of said engine-driven wheels and the effective driving force of said electric-motor-driven wheels, and said switching means switch the presently-selected output control method to the output control method corresponding to the one of said total effective driving forces predicted to have a greater value.

11. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 9, further comprising steering-amount detecting means for detecting the steering amount of the vehicle, wherein in the event that the steering amount detected by said steering-amount detecting means is equal to or greater than a predetermined value, said switching means select said first control means.

12. A control device for controlling a hybrid-four-wheel-driven vehicle according to claim 9, said switching means comprising:

effective-driving-force computation means for computing the present effective driving force of said engine-driven wheels, and the present effective driving force of said electric-motor-driven wheels;

acceleration driving force computation means for computing the acceleration driving force for achieving an acceleration request value;

target-effective-driving-force computation means for obtaining target effective driving force by making the sum of said present effective driving force of said engine-driven wheels and said present effective driving force of said electric-motor-driven wheels, computed by said effective-driving-force computation means, and said acceleration driving force;

effective-driving-force-history computation means for obtaining history data of said effective engine-driven-wheel driving force and said effective electric-motor-driven-wheel driving force corresponding to last slippage data for a predetermined past period;

maximum-effective-driving-force computation means for computing the maximum values of said effective driving force for said engine-driven wheels and said electric-motor-driven wheels based upon said history data;

first target-engine-output computation means for obtaining first target engine output corresponding to the maximum value of the effective engine-driven-wheel driving force obtained by said maximum-effective-driving-force computation means;

first total-effective-driving-force computation means wherein the effective driving force of said engine-driven wheels and the effective driving force of said electric-motor-driven wheels, each of which correspond to said first target engine output, are obtained based upon said history data, and target total effective driving force according to said first control method is obtained based thereupon;

target electric-motor-driven-wheel driving force computation means for obtaining target driving force of said electric-motor-driven wheels, by subtracting said maximum effective engine-driven-wheel driving force multiplied by a predetermined reduction coefficient from said target effective driving force;

target electric-motor-torque computation means for obtaining the target electric-motor torque based upon said target electric-motor-driven-wheel driving force;

second target-engine-output computation means for obtaining the target engine output required for achieving said target electric-motor output;

target effective engine-driven-wheel driving force computation means for obtaining the target effective driving force of said engine-driven wheels corresponding to said target engine output;

second total effective driving force computation means for obtaining the target total effective driving force according to said second control method by making the sum of said target effective electric-motor-driven-wheel driving force and said target effective engine-driven-wheel driving force; and

selection means wherein comparison is made between said target total effective driving forces according to said first control method and said second control method, and the one of said control methods corresponding to said target total effective driving force having a greater value is selected.