SUSPENSION CONTROL APPARATUS AND VEHICLE CONTROL APPARATUS

• US 20110241299A1
• Filed: 03/25/2011
• Published: 10/06/2011
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: HARADA, Naofumi, GANKAI, Tatsuya, KUMEMURA, Yoichi
• Granted Patent: US 8,348,283 B2
• Time in Patent Office: Days
• US Class Current: 280/5.513
• CPC Class Codes: B60G 17/08 Characteristics of fluid dampers adjusting fluid dampers in general F16F9/44 - F16F9/53
• CPC Class Codes: B60G 2400/102 vertical
• CPC Class Codes: B60G 2400/202 Piston speed; Relative velocity between vehicle body and wheel
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/39 Brake pedal position
• CPC Class Codes: B60G 2400/518 in damper
• CPC Class Codes: B60G 2400/5182 Fluid damper
• CPC Class Codes: B60G 2500/10 Damping action or damper
• CPC Class Codes: B60G 2500/104 continuous
• CPC Class Codes: B60G 2800/94 Electronic Stability Program (ESP, i.e. ABS+ASC+EMS)
• CPC Class Codes: B60T 2260/06 Active Suspension System
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02

Abstract

A suspension control apparatus selectively performs at least one of: compression-stroke control performed when a wheel load is increased, for setting a damping-force characteristic of at least one of damping-force variable dampers, which is provided on a side of at least one wheel whose wheel load is to be increased among a plurality of wheels, to a hard side in an early stage of a compression stroke and switching the damping-force characteristic to a soft side in a latter stage of the compression stroke; extension-stroke control performed when the wheel load is increased, for setting the damping-force characteristic to the soft side in an early stage of an extension stroke and switching the damping-force characteristic to the hard side in a latter stage of the extension stroke; compression-stroke control performed when the wheel load is reduced, for setting the damping-force characteristic of at least one of the damping-force variable dampers, which is provided on a side of at least one wheel whose wheel load is to be reduced, to the soft side in the early stage of the compression stroke and switching the damping-force characteristic to the hard side in the latter stage of the compression stroke; and extension-stroke control performed when the wheel load is reduced, for setting the damping-force characteristic to the hard side in the early stage of the extension stroke and switching the damping-force characteristic to the soft side in the latter stage of the extension stroke.

Claims

1. A suspension control apparatus, comprising:

damping-force adjustable shock absorbers provided between a vehicle body of a vehicle and wheels, each of the damping-force adjustable shock absorbers having a damping-force characteristic adjustable between a soft side and a hard side; and

a controller for variably controlling the damping-force characteristic of each of the damping-force adjustable shock absorbers,

wherein the controller performs at least one control of;

compression-stroke control performed when a wheel load is increased, for setting the damping-force characteristic of at least one of the damping-force adjustable shock absorbers, which is provided on a side of at least one wheel whose wheel load is to be increased among the plurality of wheels, to the hard side in an early stage of a compression stroke and then switching the damping-force characteristic to the soft side in a latter stage of the compression stroke;

extension-stroke control performed when the wheel load is increased, for setting the damping-force characteristic of the at least one of the damping-force adjustable shock absorbers, which is provided on the side of the at least one wheel whose wheel load is to be increased among the plurality of wheels, to the soft side in an early stage of an extension stroke and then switching the damping-force characteristic to the hard side in a latter stage of the extension stroke;

compression-stroke control performed when the wheel load is reduced, for setting the damping-force characteristic of at least one of the damping-force adjustable shock absorbers, which is provided on a side of at least one wheel whose wheel load is to be reduced among the plurality of wheels, to the soft side in the early stage of the compression stroke and then switching the damping-force characteristic to the hard side in the latter stage of the compression stroke; and

extension-stroke control performed when the wheel load is reduced, for setting the damping-force characteristic of the at least one of the damping-force adjustable shock absorbers, which is provided on the side of the at least one wheel whose wheel load is to be reduced among the plurality of wheels, to the hard side in the early stage of the extension stroke and then switching the damping-force characteristic to the soft side in the latter stage of the extension stroke.

2. A suspension control apparatus according to claim 1, wherein the damping-force characteristic is switched when an extension or compression acceleration of the at least one damping-force adjustable shock absorber becomes zero.

3. A suspension control apparatus according to claim 1, wherein the damping-force characteristic is switched when an extension or compression rate of the at least one damping-force adjustable shock absorber becomes maximum.

4. A suspension control apparatus according to claim 1, wherein the controller gradually switches the damping-force characteristic of the at least one damping-force adjustable shock absorber between the early stage and the latter stage in at least any one of the compression-stroke control performed when the wheel load is increased, the extension-stroke control performed when the wheel load is increased, the compression-stroke control performed when the wheel load is reduced, and the extension-stroke control performed when the wheel load is reduced.

5. A suspension control apparatus according to claim 4, wherein the damping-force characteristic is switched

by variably controlling the damping-force characteristic of the at least one of the damping-force adjustable shock absorbers provided on the side of the at least one wheel whose wheel load is to be increased among the plurality of wheels as a damping-force characteristic proportional to a compression/extension acceleration of the at least one of the damping-force adjustable shock absorbers, and

by variably controlling the damping-force characteristic of the at least one of the damping-force adjustable shock absorbers provided on the side of the at least one wheel whose wheel load is to be reduced among the plurality of wheels as a damping-force characteristic proportional to a compression/extension acceleration of the at least one of the damping-force adjustable shock absorbers.

6. A suspension control apparatus according to claim 4, wherein the damping-force characteristic is switched

by variably controlling the damping-force characteristic of the at least one of the damping-force adjustable shock absorbers provided on the side of the at least one wheel whose wheel load is to be increased among the plurality of wheels as a damping-force characteristic proportional to a compression/extension rate of the at least one of the damping-force adjustable shock absorbers, and

by variably controlling the damping-force characteristic of the at least one of the damping-force adjustable shock absorbers provided on the side of the wheel whose wheel load is to be reduced among the plurality of wheels as a damping-force characteristic proportional to a compression/extension rate of the at least one of the damping-force adjustable shock absorbers.

7. A suspension control apparatus according to claim 1, wherein the switching of the damping-force characteristic is performed by control for fixing the damping-force characteristic of the at least one damping-force adjustable shock absorber to one of the hard side and the soft side in one of the early stage of the extension stroke and the early stage of the compression stroke and then gradually changing the damping-force characteristic to the other one of the hard side and the soft side.

8. A suspension control apparatus according to claim 1, wherein the switching of the damping-force characteristic is performed by control for gradually changing the damping-force characteristic of the at least one damping-force adjustable shock absorber from one of the hard side and the soft side to the other one of the hard side and the soft side during one of the extension stroke and the compression stroke, and fixing the damping-force characteristic of the at least one damping-force adjustable shock absorber to the other one of the hard side and the soft side in the latter stage of the one of the extension stroke and the compression stroke.

9. A suspension control apparatus according to claim 1, wherein a braking force is applied to the at least one wheel whose wheel load is to be increased among the plurality of wheels.

10. A suspension control apparatus according to claim 9, wherein the braking force is applied by vehicle stability control.

11. A vehicle control apparatus, comprising:

damping-force adjustable shock absorbers provided between a vehicle body of a vehicle and wheels, each of the damping-force adjustable shock absorbers having a damping-force characteristic adjustable between a soft side and a hard side;

a controller for variably controlling the damping-force characteristic of each of the damping-force adjustable shock absorbers;

a braking device provided to each of the wheels of the vehicle; and

braking-force controller for controlling a braking force of the braking device,

wherein the controller performs at least one of;

compression-stroke control performed when a wheel load is increased, for setting the damping-force characteristic of at least one of the damping-force adjustable shock absorbers for at least one of the wheels, to which the braking force is applied by the braking-force controller, to the hard side in an early stage of a compression stroke and switching the damping-force characteristic to the soft side in a latter stage of the compression stroke; and

extension-stroke control performed when the wheel load is increased, for setting the damping-force characteristic of at least one of the damping-force adjustable shock absorbers for at least one of the wheels, to which the braking force is applied by the braking-force controller, to the soft side in an early stage of an extension stroke and switching the damping-force characteristic to the hard side in a latter stage of the extension stroke.

12. A vehicle control apparatus, comprising:

damping-force adjustable shock absorbers provided between a vehicle body of a vehicle and wheels, each of the damping-force adjustable shock absorbers having a damping-force characteristic adjustable between a soft side and a hard side;

a controller for variably controlling the damping-force characteristic of each of the damping-force adjustable shock absorbers;

a braking device provided to each of the wheels of the vehicle; and

braking-force controller for controlling a braking force of the braking device,

wherein the controller performs at least one of;

compression-stroke control performed when a wheel load is reduced, for setting the damping-force characteristic of at least one of the damping-force adjustable shock absorbers for at least one of the wheels, which is free from application of the braking force when the braking-force controller applies the braking force to any of the wheels, to the soft side in an early stage of a compression stroke and switching the damping-force characteristic to the hard side in a latter stage of the compression stroke; and

extension-stroke control performed when the wheel load is reduced, for setting the damping-force characteristic of at least one of the damping-force adjustable shock absorbers for at least one of the wheels, which is free from application of the braking force when the braking-force controller applies the braking force to any of the wheels, to the hard side in an early stage of an extension stroke and switching the damping-force characteristic to the soft side in a latter stage of the extension stroke.