Vehicle suspensions

• US 6,471,218 B1
• Filed: 05/17/2001
• Issued: 10/29/2002
• Est. Priority Date: 08/22/1998
• Status: Expired due to Term

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Land Rover Group Limited (TATA Motors Limited)
• Inventors: Griffiths, Adrian Michael, Tang, Jing Shen, Burdock, William
• Primary Examiner(s): English, Peter C.
• Application Number:
  US09/763,382
• Time in Patent Office: 530 Days
• Field of Search: 280/5.502, 280/5.503, 280/5.506, 280/5.508, 280/5.51, 280/5.511, 280/755
• US Class Current: 280/5.502
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 17/0195 characterised by the regulation being combined with other vehicle control systems conjoint control of vehicle sub-units including control of suspension systems B60W10/22
• CPC Class Codes: B60G 21/0555 including an actuator inducing vehicle roll
• CPC Class Codes: B60G 2202/135 Stabiliser bar and/or tube
• CPC Class Codes: B60G 2202/413 Hydraulic actuator
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/61 Load distribution
• CPC Class Codes: B60G 2400/91 Frequency
• CPC Class Codes: B60G 2500/20 Spring action or springs
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2800/182 Traction
• CPC Class Codes: B60G 2800/212 Transversal; Side-slip during cornering
• CPC Class Codes: B60G 2800/214 by varying the load distribution
• CPC Class Codes: B60G 2800/22 Braking, stopping
• CPC Class Codes: B60G 2800/244 Oversteer
• CPC Class Codes: B60G 2800/91 Suspension Control
• CPC Class Codes: B60G 2800/93 Skid or slide control [ASR]

Abstract

In an active roll control system for a vehicle, anti-roll bars (26, 30) are provided with actuators (28, 32) which can provide a torque in the anti-roll bars to control vehicle body roll. Under certain cornering conditions when the vehicle is liable to over-steer, the pressure supply to the actuators is pulsed so that the front wheels of the vehicle tend to break away more easily, thereby reducing over-steer.

Claims

1. A suspension system for connecting a wheel to a sprung part of a vehicle, the wheel being arranged to contact the ground with a contact force which controls a level of adhesion between the wheel and the ground, the system including:

a movable part of the suspension system which can move relative to said sprung part thereby to allow vertical travel of the wheel;

an actuator arranged to produce an actuator force between said sprung part and said movable part;

a cornering sensor arranged to detect predetermined cornering conditions of the vehicle; and

a controller, wherein the controller is arranged, in the event of detection of said predetermined cornering conditions, to promote lateral slipping of the wheel by producing a rapid variation in said actuator force so as to produce a pulsing of said contact force causing a reduction in said level of adhesion, so as to control the steering characteristics of the vehicle.

2. A system according to claim 1 for a vehicle having front wheels and rear wheels, wherein the rapid variation is arranged to promote lateral slipping of the front wheels during cornering thereby reducing oversteer.

3. A system according to claim 1 wherein the cornering sensor is arranged to measure lateral acceleration of the vehicle, and the controller is arranged to control the actuator force in response to the measured lateral acceleration.

4. A system according to claim 3 wherein the controller is arranged to produce a rapid change in said actuator force when the measured lateral acceleration reaches a predetermined level such that a change in lateral acceleration of the vehicle produces a rapid change in the actuator force.

5. A system according to claim 1 for a vehicle having steered wheels, the system further comprising a steering angle sensor for measuring the steering angle of the steered wheels, wherein the control of said rapid variation is dependent on the steering angle.

6. A system according to claim 1 further comprising a vehicle speed sensor, wherein the control of said rapid variation is dependent on the vehicle speed.

7. A system according to claim 6 wherein the rapid variation is only produced when the vehicle speed exceeds a predetermined magnitude.

8. A system according to claim 1 further comprising a vehicle deceleration sensor, wherein the rapid variation is produced in response to detected deceleration of the vehicle.

9. A system according to claim 8 for a vehicle having an engine and an engine speed sensor, wherein the engine speed sensor forms the vehicle deceleration sensor.

10. A system according to claim 8 for a vehicle having a driver-operated control input and a sensor for measuring movement of said input, wherein said sensor forms the deceleration sensor.

11. A system according to claim 1 wherein said rapid variation in actuator force comprises a pulsed change.

12. A system according to claim 1 wherein the controller is arranged to produce pulsed variations in the actuator force of a controlled frequency in the event of said predetermined cornering conditions.

13. A system according to claim 1 wherein the actuator comprises a strut arranged to produce forces in a vertical direction between said wheel and said sprung part of the vehicle.

14. A system according to claim 1 for a vehicle having two wheels, wherein the actuator is arranged to urge the two wheels in opposite vertical directions.

15. A system according to claim 14 wherein the actuator is a roll-control actuator, said two wheels being on opposite sides of the vehicle.

16. A system according to claim 15 for a vehicle having opposite ends and wheels at each of said ends, wherein said actuator controls vertical wheel travel of the wheels at one end of the vehicle only.

17. A system according to claim 16 further comprising a second actuator arranged to control vertical movement of the wheels at the other end of the vehicle only, the two actuators being controllable independently.

18. A vehicle including a suspension system according to claim 1.