Suspension control system for automotive vehicle
First Claim
1. A suspension control system for an automotive vehicle having a vehicle body, at least one wheel and a suspension through which the vehicle body carries the at least one wheel, the system comprising:
- changing means for changing a performance characteristic of the suspension;
a road surface sensor for detecting roughness of a road surface on a road located at a predetermined distance in front of the automotive vehicle and generating an output corresponding to the detected roughness of the road surface;
a speed sensor for detecting the running speed of the automotive vehicle; and
control means for controlling the operation of the changing means in accordance with the outputs of the road surface sensor and the speed sensor, said control means includingcalculating means for calculating a point of time at which the at least one wheel will reach the roughness of the road surface detected by the road surface sensor, on the basis of the output of the speed sensor,means for defining a control region of a predetermined minimum roughness and a predetermined maximum roughness, the predetermined maximum roughness being established to prevent a bottoming out of the suspension,inhibiting means for inhibiting change of the performance characteristic of the suspension to a flexible mode if the output of the road surface sensor is determined to be outside the defined control region, andoutputting means for outputting a command signal to the changing means at said calculated point of time to change the performance characteristic of the suspension to a flexible mode if the output of the road surface sensor is determined to be within the defined control region.
1 Assignment
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Accused Products
Abstract
A system is for controlling a suspension performance detecting the road surface condition in front of an automotive vehicle. A road surface sensor generates an output corresponding to the size of roughness on a road surface located at a predetermined distance in front of the vehicle. A suspension damping coefficient is changed to a smaller value upon lapse of a delay time. The delay time is calculated on the basis of the output of a speed sensor, the delay time being the time required for the wheel to reach the detected rough roads surface. The changing of the suspension damping coefficient occurs on condition that the output of the road surface sensor falls within a control region defined by a lower threshold value and an upper threshold value. Accordingly, the change of the suspension damping coefficient to a smaller value is inhibited when an extremely rough road surface is detected in front of the vehicle, whereby a bottoming out of the suspension which may occur is prevented when the vehicle runs over the extremely rough road surface. Further, the ride feeling is improved when the vehicle runs over a moderately rough road surface.
76 Citations
16 Claims
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1. A suspension control system for an automotive vehicle having a vehicle body, at least one wheel and a suspension through which the vehicle body carries the at least one wheel, the system comprising:
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changing means for changing a performance characteristic of the suspension; a road surface sensor for detecting roughness of a road surface on a road located at a predetermined distance in front of the automotive vehicle and generating an output corresponding to the detected roughness of the road surface; a speed sensor for detecting the running speed of the automotive vehicle; and control means for controlling the operation of the changing means in accordance with the outputs of the road surface sensor and the speed sensor, said control means including calculating means for calculating a point of time at which the at least one wheel will reach the roughness of the road surface detected by the road surface sensor, on the basis of the output of the speed sensor, means for defining a control region of a predetermined minimum roughness and a predetermined maximum roughness, the predetermined maximum roughness being established to prevent a bottoming out of the suspension, inhibiting means for inhibiting change of the performance characteristic of the suspension to a flexible mode if the output of the road surface sensor is determined to be outside the defined control region, and outputting means for outputting a command signal to the changing means at said calculated point of time to change the performance characteristic of the suspension to a flexible mode if the output of the road surface sensor is determined to be within the defined control region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for controlling suspension of an automotive vehicle, comprising the steps of:
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(a) detecting roughness of a road surface on a road located at a predetermined distance in front of the automotive vehicle; (b) determining if the detected roughness is greater than or equal to a predetermined minimum roughness; (c) determining if the detected roughness is less than a predetermined maximum roughness, the predetermined maximum roughness being established to prevent a bottoming out of the suspension; (d) inhibiting change of a performance characteristic of the suspension to a flexible mode if the detected roughness is determined to be less than the predetermined minimum roughness in step (b) or if the detected roughness is determined to be greater than or equal to the predetermined maximum roughness in step (c); and (e) changing a performance characteristic of the suspension if the detected roughness is determined to be greater than or equal to the predetermined minimum roughness in step (b) and less than the predetermined maximum roughness in step (c). - View Dependent Claims (12, 13)
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14. A method of inhibiting change of a performance characteristic of a suspension to a flexible mode in an automotive vehicle, comprising the steps of:
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(a) detecting roughness of a road surface; (b) determining if the detected roughness is less than a predetermined minimum roughness; (c) determining if the detected roughness is greater than or equal to a predetermined maximum roughness; (d) inhibiting change of a performance characteristic of the suspension to a flexible mode if the detected roughness is determined to be less than the predetermined minimum roughness in step (b) or greater than or equal to the predetermined maximum roughness in step (c). - View Dependent Claims (15, 16)
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Specification