Speed dependent suspension control
First Claim
1. A method for operating a controllable suspension connected between a body and wheels of a vehicle, said method comprising the steps of:
- sensing the speed of the vehicle;
determining a lateral acceleration damping threshold for switching a damping factor of said controllable suspension in response to the sensed speed of the vehicle by performing the steps of;
determining whether the sensed speed of said vehicle is less than or equal to a first speed, or greater than said first speed;
solving a first damping equation, dependent upon the sensed speed of said vehicle, if the sensed speed of said vehicle is less than or equal to said first speed; and
solving a second damping equation, dependent upon the sensed vehicle speed and different than said first damping equation, if the sensed speed of said vehicle is greater than said first speed;
determining the lateral acceleration of the vehicle;
comparing the determined lateral acceleration of the vehicle to said lateral acceleration damping threshold; and
setting the damping factor of said controllable suspension in response to the result of said step of comparing the determined lateral acceleration of the vehicle to said lateral acceleration damping threshold.
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Accused Products
Abstract
Vehicle speed is measured and used to calculate lateral acceleration of the vehicle and speed dependent thresholds to which the lateral acceleration of the vehicle is compared to determine when to change a controllable suspension system of the vehicle to improve operation of the suspension system. The controllable suspension system includes air springs and variable damping shock absorbers switchable between soft and firm damping rates. At speeds above a given speed, lateral accelerations exceeding first speed dependent thresholds will result in switching the shock absorbers to firm and/or closing gate valves which intercouple the left and right air springs to decrease vehicle roll. For slower speeds less than the given speed, the suspension system control is desensitized such that lateral accelerations of the same given magnitudes, for example due to entering a parking space or other low speed maneuver, do not alter the suspension. Switch back of shock absorbers from firm to soft and opening of the gate valves can be based on expiration of an elapsed time period or detection of the lateral acceleration of the vehicle falling below second speed determined thresholds.
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Citations
18 Claims
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1. A method for operating a controllable suspension connected between a body and wheels of a vehicle, said method comprising the steps of:
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sensing the speed of the vehicle; determining a lateral acceleration damping threshold for switching a damping factor of said controllable suspension in response to the sensed speed of the vehicle by performing the steps of; determining whether the sensed speed of said vehicle is less than or equal to a first speed, or greater than said first speed; solving a first damping equation, dependent upon the sensed speed of said vehicle, if the sensed speed of said vehicle is less than or equal to said first speed; and solving a second damping equation, dependent upon the sensed vehicle speed and different than said first damping equation, if the sensed speed of said vehicle is greater than said first speed; determining the lateral acceleration of the vehicle; comparing the determined lateral acceleration of the vehicle to said lateral acceleration damping threshold; and setting the damping factor of said controllable suspension in response to the result of said step of comparing the determined lateral acceleration of the vehicle to said lateral acceleration damping threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for operating a controllable suspension connected between a body and wheels of a vehicle, said method comprising the steps of:
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sensing the speed of the vehicle; determining a lateral acceleration gating threshold for switchably isolating a left side of said controllable suspension from a right side of said controllable suspension by performing the steps of; determining whether the sensed speed of said vehicle is less than or equal to a first speed, or greater than said first speed; solving a first gating equation, dependent upon the sensed speed vehicle, if the sensed speed of said vehicle is less than or equal to said first speed; and solving a second gating equation, dependent upon the sensed vehicle speed and different than said first gating equation, if the sensed speed of said vehicle is greater than said first speed; determining the lateral acceleration of the vehicle; comparing the determined lateral acceleration of the vehicle to said gating threshold; and controlling the isolation of said left side of said controllable suspension from said right side of said controllable suspension in response to the step of comparing the determined lateral acceleration of the vehicle to said gating threshold. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification