Electronic control of vehicle air suspension

• US 7,192,032 B2
• Filed: 05/06/2005
• Issued: 03/20/2007
• Est. Priority Date: 04/23/2002
• Status: Expired due to Fees

• Current Assignee: Barksdale Inc (Crane Company)
• Original Assignee: Barksdale Inc (Crane Company)
• Inventors: Shah, Hasmukh R., Dodd, C Ian
• Primary Examiner(s): Dickson; Paul N.
• Assistant Examiner(s): Sliteris; Joselynn Y.
• Application Number:
  US11/123,728
• Publication Number:
  US 20050200089A1
• Time in Patent Office: 683 Days
• Field of Search: 280/5.506, 280/5.508, 280/5.5, 280/5.502, 280/5.514, 280/124.128, 280/124.153, 280/124.16, 280/124.161
• US Class Current: 280/5.508
• CPC Class Codes: B60G 17/0155 pneumatic unit
• CPC Class Codes: B60G 17/016 characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input B60G17/017 takes precedence
• CPC Class Codes: B60G 17/01908 Acceleration or inclination sensors characterised by the use of gyroscopes B60G21/08
• CPC Class Codes: B60G 17/01925 Pendulum-type devices
• CPC Class Codes: B60G 17/01933 Velocity, e.g. relative velocity-displacement sensors
• CPC Class Codes: B60G 17/0523 Regulating distributors or valves for pneumatic springs
• CPC Class Codes: B60G 2200/31 with two trailing arms rigidly connected to the axle
• CPC Class Codes: B60G 2200/314 with longitudinally arranged arms articulated on the axle
• CPC Class Codes: B60G 2202/152 Pneumatic spring
• CPC Class Codes: B60G 2202/412 Pneumatic actuator
• CPC Class Codes: B60G 2204/11 Mounting of sensors thereon
• CPC Class Codes: B60G 2300/026 Heavy duty trucks
• CPC Class Codes: B60G 2300/0262 Multi-axle trucks
• CPC Class Codes: B60G 2400/051 Angle
• CPC Class Codes: B60G 2400/0511 Roll angle
• CPC Class Codes: B60G 2400/0512 Pitch angle
• CPC Class Codes: B60G 2400/252 vertical
• CPC Class Codes: B60G 2400/60 Load
• CPC Class Codes: B60G 2400/63 Location of the center of gravity
• CPC Class Codes: B60G 2401/12 Strain gauge
• CPC Class Codes: B60G 2401/25 : Capacitance type, e.g. as level indicator
• CPC Class Codes: B60G 2401/902 : the sensor being an xy axis sensor
• CPC Class Codes: B60G 2500/20 : Spring action or springs
• CPC Class Codes: B60G 2500/30 : Height or ground clearance
• CPC Class Codes: B60G 2600/02 : Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2600/124 : Error signal
• CPC Class Codes: B60G 2600/604 : low pass
• CPC Class Codes: B60G 2800/012 : Rolling condition
• CPC Class Codes: B60G 2800/019 : Inclination due to load distribution or road gradient
• CPC Class Codes: B60G 2800/70 : Estimating or calculating vehicle parameters or state variables
• CPC Class Codes: B60G 2800/702 : Improving accuracy of a sensor signal
• CPC Class Codes: B60G 2800/915 : Suspension load distribution

Abstract

A system is provided for use on large vehicles of the type wherein the vehicle frame (12) is supported on vehicle axle assemblies (14, 20, 22) through air bags (26, 30, 32), and each air bag has a lower end coupled to the lower end of an arm such as a swing arm (112) whose upper end is pivotally mounted on the frame. The height of the air bag is sensed by a pair of tilt sensors (50, 52), one on a tilt arm such as the swing arm (112), that has one end pivotally connected to the vehicle frame and an opposite end at least pivotally connected to the vehicle axle assembly. The other sensor senses tilt of the vehicle frame about an axis parallel to the axes of pivoting of the tilt arm. Each tilt sensor senses tilt of its location with respect to gravity, and the difference in tilt indicates air bag height.

Claims

1. A method for controlling a vehicle suspension system, the vehicle suspension system including a vehicle frame, a plurality of axle assemblies that have axles that support said frame above the ground, including a first axle assembly with a first axle, a first fluid operated lifting actuator that extends from substantially said first axle assembly to said frame to support at least part of the frame weight on said first axle assembly, apparatus for sensing the height of the lifting actuator including a tilt arm having first and second end portions pivotally coupled about a predetermined axis of the frame respectively to said frame and to said first axle, and a first tilt sensor, at least one component of which is mounted on a first location on said tilt arm, said first tilt sensor generating a signal indicating tilt, and a control that includes a filter means connected to said first tilt sensor to receive said signal, said control including at least one means to control said first lifting actuator, the steps of the method comprising:

sensing the tilt angle of said first location on said tilt arm and generating a signal indicating the tilt angle of said first location about a predetermined axis of said frame, thereby indicating a tilt of said tilt arm and indicating said first lifting actuator height; and

controlling fluid flow into or out of said first lifting actuator to avoid flowing fluid into or out of said first lifting actuator when the tilt of said tilt arm lasts less than approximately a predetermined time period, and avoiding flowing fluid into or out of said first lifting actuator when said first lifting actuator height is within a predetermined distance above or below a predetermined height.

2. The method of claim 1, wherein said vehicle suspension system further includes a second tilt sensor mounted on a second location that is fixed relative to said vehicle frame to tilt therewith for sensing tilt of said second location about said predetermined axis on said frame, and for sensing tilt about a second tilt sensor axis transverse to said predetermined axis, and further comprising:

generating a signal indicating tilt angles of said second location about said predetermined axis and about said second tilt sensor axis transverse to said predetermined axis; and

generating a signal representing a difference in tilt angles of said first and second tilt sensors about said predetermined axis, to thereby indicate lifting actuator height even when the vehicle is on an inclined surface.

3. The method described in claim 2, further comprising:

controlling the height of said first lifting actuator; and

controlling the flow of fluid into and out of said first lifting actuator to flow fluid into said first lifting actuator when said difference in tilt angles decreases below a first predetermined angle and to flow fluid out of the first lifting actuator when said difference in tilt angles increases above a second predetermined angle.

4. The method of claim 2, wherein said vehicle frame has left and right laterally opposite vehicle side portions, said first lifting actuator and first tilt arm are located at said vehicle left side portion, and a second lifting actuator is located on said vehicle right side portion, and further including a third tilt sensor mounted on said vehicle frame and orientated to sense sideward tilt of said vehicle frame about a longitudinal axis, and said second tilt sensor axis transverse to said predetermined axis is the longitudinal axis for sensing sideward tilt, said control being coupled to said first, second and third tilt sensors, and comprising:

controlling the flow of fluid into and out of said first and second lifting actuators partially in accordance with sideward tilt of said vehicle.

5. The method of claim 2, wherein said vehicle frame has a vehicle left side portion and a vehicle right side portion, said vehicle left side portion and said vehicle right side portion being laterally opposite of one another, and said first lifting actuator and first tilt arm are located at said vehicle left side portion, and including a second lifting actuator and second tilt arm located on said vehicle right side portion, and further including a third tilt sensor mounted on said second tilt arm, said control being coupled to said first, second and third tilt sensors, and comprising:

controlling the flow of fluid into and out of said first lifting actuator and said second lifting actuator, respectively, according to the difference in angle between said first and second tilt sensors about said predetermined axis, and the difference in angle between said second and third tilt sensors about said axis transverse to said predetermined axis.

6. The method of claim 1, wherein said time period is on the order of magnitude of ten seconds.

7. The method of claim 1, wherein said first lifting actuator is an air bag.