Locking suspension system

• US 20040084266A1
• Filed: 11/04/2002
• Published: 05/06/2004
• Est. Priority Date: 11/04/2002
• Status: Active Grant

• Current Assignee: Volvo Trucks North America Incorporated (Volvo AB)
• Original Assignee: Volvo Trucks North America Incorporated (Volvo AB)
• Inventors: White, Darris, Svartz, Bjorn O.
• Granted Patent: US 7,051,851 B2
• Time in Patent Office: Days
• US Class Current: 188/300
• CPC Class Codes: B60G 17/005 Suspension locking arrangements for retractable wheels B62D61/12
• CPC Class Codes: B60G 17/0155 pneumatic unit
• CPC Class Codes: B60G 17/0164 mainly during accelerating or braking
• CPC Class Codes: B60G 17/052 Pneumatic spring characteristics B60G17/048 takes precedence ; valves per se F16K
• CPC Class Codes: B60G 2200/30 Rigid axle suspensions
• CPC Class Codes: B60G 2202/152 Pneumatic spring
• CPC Class Codes: B60G 2204/4605 hydraulically, e.g. interrupting communication between the chambers of a hydraulic cylinder
• CPC Class Codes: B60G 2300/026 Heavy duty trucks
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/32 Torque on propulsion shaft
• CPC Class Codes: B60G 2400/33 Throttle position
• CPC Class Codes: B60G 2400/38 Speed of engine rotation
• CPC Class Codes: B60G 2400/39 Brake pedal position
• CPC Class Codes: B60G 2400/412 of steering wheel or column
• CPC Class Codes: B60G 2600/00 Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
• CPC Class Codes: B60G 2800/182 Traction
• CPC Class Codes: B60G 2800/21 Traction, slip, skid or slide control
• CPC Class Codes: B60G 2800/22 Braking, stopping
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B60G 2800/95 : Automatic Traction or Slip Control [ATC]
• CPC Class Codes: B60G 9/00 : Resilient suspensions of a rigid axle or axle housing for two or more wheels the axle being a part of a set of tandem axles B60G5/00-B60G5/065; with leaf springs B60G11/02-B60G11/08

Abstract

A method and apparatus for controlling frame rise on a heavy duty truck having a frame, a drive axle connected to the frame, and a selectively lockable suspension component disposed therebetween for maintaining the relative position therebetween. Signals indicative of at least one of the following vehicle operating parameters: engine speed, brake pressure, vehicle speed, air bag pressure, steering wheel angle, vehicle height, or throttle position are monitored and a predicted thrust is calculated that will be applied to the drive axle based on the monitored signals. The selectively lockable suspension component is locked if the predicted thrust exceeds a predetermined threshold and is also controlled with respect to other operating parameters such as whether vehicle brakes are applied, any instantaneous change in torque, vehicle operating speed, and the length of time the selectively lockable suspension component has been locked.

Claims

1. An apparatus for locking a suspension system of a heavy duty truck having a frame and a drive axle, said apparatus for preventing driveline misalignment due to frame rise comprising:

a selectively lockable suspension component connected between the truck frame and drive axle and having a locked operating mode in which frame motion away from the drive axle is inhibited and an unlocked operating mode wherein frame motion toward and away from the drive axle is permitted, the locking suspension component responsive to input signals to transition between the locked and unlocked operating modes;

a controller for receiving signals indicative of vehicle operating parameters, the controller adapted to estimate an amount of torque that will be provided at the drive axle based on the vehicle operating parameters, the controller connected to the lockable suspension component and transmitting a locking input signal to the lockable suspension component to transition to the locked operating mode when the estimated torque is above a predetermined threshold amount.

2. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of engine torque.

3. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of throttle position.

4. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of vehicle speed.

5. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of brake pressure.

6. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of clutch engagement.

7. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of individual front wheel speeds.

8. The apparatus of claim 1 wherein the controller is adapted to receive a signal indicative of air bag pressure.

9. The apparatus of claim 5 wherein the controller transmits the locking input signal when the estimated torque is above a predetermined amount and the brake pressure is below a predetermined amount.

10. The apparatus of claim 1 wherein the controller transmits the locking input signal for a predetermined amount of time.

11. The apparatus of claim 1 wherein the selectively lockable suspension component comprises a recoil locking shock absorber.

12. A method for controlling frame rise on a heavy duty truck having a frame, a drive axle connected to the frame, and a selectively lockable suspension component disposed therebetween for maintaining the relative position therebetween, the method comprising the steps of:

monitoring signals indicative of vehicle operating parameters;

calculating a predicted thrust that will be applied to the drive axle based on the monitored signals;

locking the selectively lockable suspension component if the predicted thrust exceeds a predetermined threshold.

13. The method of claim 12 wherein the monitored signals comprise signals indicative of at least one of the following vehicle operating parameters:

engine speed, engine torque, brake pressure, vehicle speed, air bag pressure, steering wheel angle, vehicle height, or throttle position.

14. The method of claim 12 comprising the steps of determining whether the vehicle brakes are engaged and unlocking the selectively lockable suspension component when the brakes are engaged.

15. The method of claim 12 comprising the step of calculating an instantaneous change in predicted thrust and unlocking the selectively lockable suspension component if the instantaneous change in predicted thrust exceeds a predetermined threshold.

16. The method of claim 12 comprising the step of monitoring vehicle speed and the length of time the selectively lockable suspension component has been locked and unlocking the selectively lockable suspension component if the vehicle speed is higher than a predetermined nominal operating speed and the selectively lockable suspension component has been locked for more than a first time limit.

17. The method of claim 12 comprising the step of monitoring vehicle speed and the length of time the selectively lockable suspension component has been locked and unlocking the selectively lockable suspension component if the vehicle speed is lower than a predetermined nominal operating speed, the predicted thrust is lower than a lower thrust threshold and the selectively lockable suspension component has been locked for more than a second time limit.

18. The method of claim 16 wherein the predetermined nominal operating speed is 40 miles per hour.

19. The method of claim 17 wherein the predetermined nominal operating speed is 40 miles per hour.

20. The method of claim 16 wherein the first time limit is 2 seconds.

21. The method of claim 17 wherein the second time limit is 2 seconds.

22. The method of claim 17 wherein the lower thrust threshold is 500 foot-pounds.

23. The method of claim 12 comprising the step of monitoring vehicle speed and the length of time the selectively lockable suspension component has been locked and unlocking the selectively lockable suspension component if the vehicle speed is lower than a predetermined nominal operating speed, the predicted thrust is greater than a lower thrust threshold and the selectively lockable suspension component has been locked for more than a third time limit.

24. The method of claim 23 wherein the predetermined nominal operating speed is 40 miles per hour.

25. The method of claim 23 wherein the lower thrust limit is 500 foot-pounds.

26. The method of claim 23 wherein the third time limit is two minutes.