Anti-lock braking system having pulsed pressure re-application
First Claim
1. An anti-skid braking system for wheeled vehicles having fluid actuated brakes associated with the vehicle wheels, comprising:
- speed sensors associated with the vehicle wheels,a control device responsive to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined to be about to lock and to later re-apply the actuating pressure to that brake when the tendency of that wheel to lock has reduced,a pressure re-apply phase being present from a wheel recovery point after a full pressure dump until reaching a threshold for starting a full pressure dump,means for pulsing said pressure dump device at intervals with at least one fixed duration pulse during the pressure re-apply phase to cause interruption to the re-application of pressure to that brake,means for controlling the initiation of said at least one fixed length pulse in response to the wheel angular deceleration being above a predetermined threshold value, andmeans for adjusting the magnitude of said predetermined threshold value in dependence upon information from the previous anti-lock braking cycle.
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Accused Products
Abstract
An anti-skid braking system for wheeled vehicles having fluid actuated brakes associated with the vehicle wheels, has speed sensors associated with the vehicle wheels, a control device responsive to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined to be about to lock and to later re-apply the actuating pressure to that brake when the tendency of that wheel to lock has reduced, pulsing of the pressure dump device at intervals during the pressure re-apply phase to cause a repeated interruption to the re-application of pressure to that brake. The pulse timing of the pulsing of the pressure dump device is controlled by the occurrence of wheel angular deceleration being determined to be equal to or in excess of a predetermined threshold value, the magnitude of which is dependent upon events from the previous anti-lock braking cycle.
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Citations
15 Claims
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1. An anti-skid braking system for wheeled vehicles having fluid actuated brakes associated with the vehicle wheels, comprising:
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speed sensors associated with the vehicle wheels, a control device responsive to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined to be about to lock and to later re-apply the actuating pressure to that brake when the tendency of that wheel to lock has reduced, a pressure re-apply phase being present from a wheel recovery point after a full pressure dump until reaching a threshold for starting a full pressure dump, means for pulsing said pressure dump device at intervals with at least one fixed duration pulse during the pressure re-apply phase to cause interruption to the re-application of pressure to that brake, means for controlling the initiation of said at least one fixed length pulse in response to the wheel angular deceleration being above a predetermined threshold value, and means for adjusting the magnitude of said predetermined threshold value in dependence upon information from the previous anti-lock braking cycle. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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- 11. A deceleration filter for use in an anti-skid braking system for wheeled vehicles, of the type comprising speed sensors associated with the vehicle wheels, a control device responsive to speed signals from the speed sensors to actuate a pressure dump device to periodically release the fluid pressure applied to the brake of any wheel which is determined to be about to lock and to later re-apply the actuating pressure to that brake when the tendency of that wheel to lock has reduced, the deceleration filter being adapted to receive deceleration values calculated from the signals provided by said wheel speed sensors and comprising checking means adapted to check the currently calculated value of deceleration against a predetermined limit and, if the calculated deceleration is less than said predetermined limit, to use the calculated value to update a stored value of decelerations.
Specification