Method of detecting an inoperable pump motor in an anti-lock braking system
AssigneeAlliedSignal Inc.
InventorsCharles E. Lindenman, Charles F. Huddleston
Life of this patent
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Abstract
An anti-lock braking system comprises a pump motor which is energized initially during vehicle drive-off and then deactivated. The deactivation voltage and subsequent motor voltages are evaluated against predetermined voltage levels for an appropriately operating pump motor to determine whether or not the anti-lock braking system should be deactivated and a failure warning mechanism activated to warn the vehicle operator of the deactivated system.
Claims16
An anti-lock braking system which determines the operability of a pump motor, comprising:
- (a) means for determining if the pump motor has been deactivated and the voltage of the pump motor at said deactivation,
- (b) means for determining if the voltage at deactivation exceeds a predetermined first voltage value,
- (c) means for initiating anti-lock braking system failure warning means if the deactivation voltage is less than said predetermined first voltage value,
- (d) means for maintaining the deactivation voltage as a shut-off voltage value if the deactivation voltage is greater than said first predetermined voltage value and proceeding to a next step (e),
- (e) means for incrementing a cycle time of the method,
- (f) means for determining if actual motor voltage is greater than a second predetermined voltage value,
- (g) means for calculating a derivative of the difference between said shut-off voltage value and said second predetermined voltage value if the actual motor voltage is less than said second predetermined voltage value,
- (h) means for determining if the calculated derivative is greater than a set fault value, and
- (i) means for initiating said anti-lock braking system failure warning means if said derivative is greater than said set fault value.
A method of determining the operability of a pump motor in an anti-lock braking system, comprising the steps of:
- (a) determining if the pump motor has been deactivated and the voltage of the pump motor at said deactivation,
- (b) determining, if the voltage at deactivation exceeds a predetermined first voltage value,
- (c) initiating anti-lock braking system failure warning means if the deactivation voltage is less than said predetermined first voltage value,
- (d) maintaining the deactivation voltage as a shut-off voltage value if the deactivation voltage is greater than said first predetermined voltage value and proceeding to a next step (e),
- (e) incrementing a cycle time of the method,
- (f) determining if actual motor voltage is greater than a second predetermined voltage value,
- (g) calculating a derivative of the difference between said shut-off voltage value and said second predetermined voltage value if the actual motor voltage is less than said second predetermined voltage value,
- (h) determining if the calculated derivative is greater than a set fault value, and
- (i) initiating said anti-lock braking system failure warning means if said derivative is greater than said set fault value.
Dependencies are inferred from the claim text.