Control apparatus for all-wheel drive vehicle

Patent metadata

Field	Value
Publication number	US-11993243-B2
Application number	US-202318465257-A
Country	US
Kind code	B2
Filing date	Sep 12, 2023
Priority date	Nov 1, 2022
Publication date	May 28, 2024
Grant date	May 28, 2024

Abstract

A control apparatus for an all-wheel drive vehicle that includes (i) a power source, (ii) a power distribution device for distributing a power from the power source to front and rear wheels, (iii) a differential limiting mechanism for placing the power distribution device in a differential limiting state in which a rotational difference between the front wheels and the rear wheels is limited, and (iv) a braking device for applying a wheel braking torque to each of the front and rear wheels. When the power distribution device is placed in the differential limiting state and the wheel braking torque is applied to each of the front wheels and the rear wheels, a torque limiting control is executed for setting an upper limit value of a torque of the power source to a smaller value when the wheel braking torque is large than when the wheel braking torque is small.

First claim

What is claimed is:

1. A control apparatus for an all-wheel drive vehicle that includes (i) front wheels, (ii) rear wheels, (iii) a power source, (iv) a power distribution device configured to distribute a power from the power source to the front wheels and the rear wheels, (v) a differential limiting mechanism configured to place the power distribution device in a differential limiting state in which a rotational difference between the front wheels and the rear wheels is limited, and (vi) a braking device configured to apply a wheel braking torque to each of the front wheels and the rear wheels, the control apparatus comprising:
circuitry configured to, when the power distribution device is placed in the differential limiting state and the wheel braking torque is applied to each of the front wheels and the rear wheels, execute a torque limiting control for setting an upper limit value of a torque of the power source to a smaller value when the wheel braking torque is large than when the wheel braking torque is small.

2. The control apparatus according to claim 1 ,
wherein the power distribution device is provided with a step-variable transmission configured to transmit the power from the power source to the front wheels and the rear wheels while changing a rotational speed of the power source, and
wherein the circuitry is configured to execute the torque limiting control when a lowest gear position is established in the step-variable transmission.

3. The control apparatus according to claim 1 , circuitry is configured to execute the torque limiting control when a running speed of the vehicle is not higher than a predetermined speed value.

4. The control apparatus according to claim 1 ,
wherein the vehicle further includes:
a power transmission device provided between the power source and the power distribution device, and
a shift operation device that is to be operated to switch between power transmission states of the power transmission device, and

wherein the circuitry is configured to execute the torque limiting control when the shift operation device is operated to select one of the power transmission states of the power transmission device that enables forward running of the vehicle or another one of the power transmission states of the power transmission device that enables reverse running of the vehicle.

5. The control apparatus according to claim 1 ,
wherein the vehicle further includes a transmission provided between the power source and the power distribution device, and
wherein the circuitry is configured to execute the torque limiting control when a lowest forward gear position or a reverse gear position is established in the transmission.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kawamata Atsushi

Classifications

• B60K17/354

  having separate mechanical assemblies for transmitting drive to the front or to the rear wheels or set of wheels · CPC title

• B60K17/348

  having differential means for driving one set of wheels, e.g. the front, at one speed and the other set, e.g. the rear, at a different speed (B60K17/346 takes precedence) · CPC title

• B60K17/3465 Primary

  self-actuated means, e.g. differential locked automatically by difference of speed · CPC title

• B60K23/0808 Primary

  for varying torque distribution between driven axles, e.g. by transfer clutch · CPC title

• B60W10/119 Primary

  including control of all-wheel-driveline means, e.g. transfer gears or clutches for dividing torque between front and rear axle (B60W10/14 takes precedence) · CPC title