Temperature responsive suspension system control
First Claim
1. A suspension system control method for use in a suspension system including a damper controllable in response to an actuator command, comprising the steps of:
- measuring an ambient temperature outside a vehicle;
measuring a relative velocity of a suspension system damper;
responsive to the relative velocity and the ambient temperature, estimating a damping fluid temperature of damping fluid within the damper;
comparing the estimated damping fluid temperature to a predetermined threshold;
if the damping fluid temperature is not above the predetermined threshold, constraining the actuator command to a cold temperature maximum value, wherein the cold temperature maximum value is less than a corresponding normal non-cold temperature maximum value for the actuator command; and
outputting the actuator command to the damper.
3 Assignments
0 Petitions
Accused Products
Abstract
A suspension system control method comprising the steps of: measuring an ambient temperature outside a vehicle; measuring a relative velocity of a suspension system damper; responsive to the relative velocity and the ambient temperature, estimating a damping fluid temperature of damping fluid within the actuator; comparing the estimated damping fluid temperature to a predetermined threshold; if the damping fluid temperature is not above the predetermined threshold, constraining an actuator command to a cold temperature maximum value, wherein the cold temperature maximum value is less than a corresponding normal non-cold temperature maximum value for the actuator command; and outputting the actuator command to the damper, wherein the occurrence of suspension noise and harshness during cold temperature operation of the vehicle is minimized.
18 Citations
6 Claims
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1. A suspension system control method for use in a suspension system including a damper controllable in response to an actuator command, comprising the steps of:
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measuring an ambient temperature outside a vehicle; measuring a relative velocity of a suspension system damper; responsive to the relative velocity and the ambient temperature, estimating a damping fluid temperature of damping fluid within the damper; comparing the estimated damping fluid temperature to a predetermined threshold; if the damping fluid temperature is not above the predetermined threshold, constraining the actuator command to a cold temperature maximum value, wherein the cold temperature maximum value is less than a corresponding normal non-cold temperature maximum value for the actuator command; and outputting the actuator command to the damper.
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2. A vehicle suspension system control method comprising the steps of:
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determining ambient temperature; setting an initial damping fluid temperature estimation equal to the ambient temperature, and thereafter iteratively determining a relative velocity of at least one damper of the suspension system; determining, responsive to the relative velocity and the damping fluid temperature estimation, a damper force value; estimating heat input to the damper responsive to the relative velocity and the damper force value; estimating heat outflow from the damper responsive to the estimated damper fluid temperature and the ambient temperature; determining a change in temperature of the damping fluid responsive to the estimated heat input and the estimated heat outflow; updating the estimated damper temperature responsive to the estimated damper fluid change in temperature; and if the estimated damping fluid temperature is not above a predetermined threshold, constraining a damper actuator command to a predetermined maximum value for cold temperature operation of the damper to minimize occurrence of suspension noise and harshness during cold temperature vehicle operation.
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3. A method of indicating cold temperature operation of a suspension system damper, comprising the steps of:
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measuring an ambient temperature outside a vehicle; measuring a relative velocity of a suspension system damper; responsive to the relative velocity and the ambient temperature, estimating a damping fluid temperature of damping fluid within the damper; comparing the estimated damping fluid temperature to a predetermined threshold; wherein an estimated damping fluid temperature below the predetermined threshold indicates cold temperature operation of the damper.
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4. A method of indicating cold temperature operation of a suspension system damper comprising the steps of:
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determining ambient temperature; setting an initial damping fluid temperature estimation equal to the ambient temperature, and thereafter iteratively determining a relative velocity of at least one damper of the suspension system; determining, responsive to the relative velocity and the damping fluid temperature estimation, a damper force value; estimating a heat input to the damper responsive to the relative velocity and the damper force value; estimating a heat outflow from the damper responsive to the estimated damper fluid temperature and the ambient temperature; determining a change in temperature of the damping fluid responsive to the estimated heat input and the estimated heat outflow; updating the estimated damper temperature responsive to the estimated damper fluid change in temperature; and if the estimated damping fluid temperature is not above a predetermined threshold, indicating cold temperature operation of the damper.
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5. A controllable suspension system comprising:
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means for sensing ambient temperature; a controllable variable force damper with a piston and a cylinder, wherein the controllable variable force damper is responsive to a damper command; means for determining a relative velocity of the piston and cylinder of the variable force damper; a microcomputer controller comprising means, responsive to the relative velocity and the ambient temperature, for estimating a damping fluid temperature of damping fluid within the damper, means for comparing the estimated damping fluid temperature to a predetermined threshold and means for indicating a cold temperature operation of the damper if the estimated damping fluid temperature is not above the predetermined threshold. - View Dependent Claims (6)
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Specification