Electronic control of vehicle air suspension
First Claim
1. A vehicle suspension system which includes a vehicle frame, a plurality of axle assemblies that have laterally-extending axles and that support said frame above the ground, including a first axle assembly with a first axle, and an air bag 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, including apparatus for sensing the height of the air bag, said vehicle suspension system comprising:
- a tilt arm having first and second end portions pivotally coupled about primarily horizontal axes respectively to said frame and to said first axle;
a first electronic tilt sensor, at least one component of which is mounted on a first location on said tilt arm and that generates an electrical signal indicating the tilt angle of said first location about a substantially horizontal axis, whereby to indicate air bag height;
a motion detector that generates a motion detection signal indicating whether or not the vehicle frame is in motion;
a control operatively connected to said first electronic tilt sensor and to said motion detector to receive said electrical signal from said first electronic tilt sensor and said motion detection signal from said motion detector, said control including at least one valve coupled to said air bag to control a flow of air into and out of said air bag; and
said control including a filter means for filtering said electrical signal that avoids flowing air into or out of said air bag when the tilt of said tilt arm lasts less than approximately a predetermined time period, wherein said control avoids flowing air into or out of said air bag when said air bag height is within a predetermined distance above or below a predetermined height, and wherein said control is operative to switch said filter means off responsive to said motion detection signal indicating said vehicle frame is not in motion.
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Accused Products
Abstract
A system is provided for use on large vehicles of the type wherein the vehicle frame is supported on vehicle axle assemblies through air bags, and each air bag has a lower end coupled to the lower end of an arm such as a swing arm whose upper end is pivotally mounted on the frame. The height of the air bag is sensed by a pair of tilt sensors, sensing tilt of its location with respect to gravity, and the difference in tilt indicates air bag height. The output of the tilt sensors may be filtered, and a motion detector allows rapid filling or dumping of air bags independent of filtering of tilt sensor signals. Control of the vehicle air suspension can also be based upon inputs from one or more air bag pressure sensors.
56 Citations
22 Claims
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1. A vehicle suspension system which includes a vehicle frame, a plurality of axle assemblies that have laterally-extending axles and that support said frame above the ground, including a first axle assembly with a first axle, and an air bag 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, including apparatus for sensing the height of the air bag, said vehicle suspension system comprising:
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a tilt arm having first and second end portions pivotally coupled about primarily horizontal axes respectively to said frame and to said first axle;
a first electronic tilt sensor, at least one component of which is mounted on a first location on said tilt arm and that generates an electrical signal indicating the tilt angle of said first location about a substantially horizontal axis, whereby to indicate air bag height;
a motion detector that generates a motion detection signal indicating whether or not the vehicle frame is in motion;
a control operatively connected to said first electronic tilt sensor and to said motion detector to receive said electrical signal from said first electronic tilt sensor and said motion detection signal from said motion detector, said control including at least one valve coupled to said air bag to control a flow of air into and out of said air bag; and
said control including a filter means for filtering said electrical signal that avoids flowing air into or out of said air bag when the tilt of said tilt arm lasts less than approximately a predetermined time period, wherein said control avoids flowing air into or out of said air bag when said air bag height is within a predetermined distance above or below a predetermined height, and wherein said control is operative to switch said filter means off responsive to said motion detection signal indicating said vehicle frame is not in motion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A vehicle suspension system for a vehicle that lies in the atmosphere and that has a frame with laterally spaced first and second opposite sides, a plurality of axle assemblies including a first axle assembly, a first tilt arm having a first arm end pivotally mounted about a horizontal axis on said frame and having a second arm end connected to a first side of said first axle assembly to move up and down with said first side of said first axle assembly, a first air bag that is supported by said first side of said first axle assembly and that supports said frame, and a source of pressured air, said vehicle suspension system comprising:
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first and second tilt sensors that each produce an electrical output indicating the tilt of the corresponding tilt sensor with respect to gravity about substantially parallel tilt axes, said first tilt sensor mounted on said first tilt arm and said second tilt sensor mounted on said frame;
a motion detector that generates a motion detection signal indicating whether or not the vehicle frame is in motion;
a control coupled to said tilt sensors, said source of pressured air and said first air bag, said control constructed to flow pressured air from said source of pressured air to said first air bag when a difference in tilt angles indicated by said first and second tilt sensors indicates an air bag height below a predetermined value, and to flow air from said first air bag into the atmosphere when the difference in tilt angles indicated by said first and second tilt sensors indicates an air bag height above a predetermined value; and
wherein said control is operatively connected to said first and second tilt sensors and said motion detector to receive said electrical output and said motion detection signal, said control including a filter means that avoids flowing air into or out of said first air bag when the difference in tilt angles indicated by said first and second tilt sensors indicating an air bag height below the predetermined value lasts less than approximately a predetermined time period, and wherein said control avoids flowing air into or out of said first air bag when said air bag height is within a predetermined distance above or below said predetermined value, and wherein said control is operative to switch said filter means off responsive to said motion detection signal indicating said vehicle frame is not in motion. - View Dependent Claims (11, 12, 13, 14)
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15. 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 a first lift 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, 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 lift actuator, the steps of the method comprising:
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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 lift actuator height;
detecting motion of the vehicle frame and generating a motion detection signal indicating whether or not the vehicle frame is in motion; and
controlling fluid flow into or out of said first lift actuator to avoid flowing fluid into or out of said first air bag 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 lift actuator when said first lift actuator height is within a predetermined distance above or below a predetermined height, and allowing flowing fluid into or out of said first lift actuator responsive to said motion detection signal indicating said vehicle frame is not in motion. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification