Method to detect marginally large air gaps on heavy vehicle wheel speed sensor installations

A processor that executes an all-wheel marginally large airgap test (AWMLAT), wherein the processor is configured to:

• upon test initiation, receive a signal from each of a plurality of wheel speed sensors on a vehicle, the signal being indicative of a exciter ring sensed by the sensor;
• and
• for each wheel speed sensor:
• monitor exciter ring frequency to determine whether exciter ring frequency is within a predetermined frequency range;
• when exciter ring frequency is within the predetermined frequency range, measure wheel speed sensor signal peak amplitude;
• compare the measured wheel speed sensor signal peak amplitude to a predetermined minimum amplitude that represents the maximum allowable airgap between the wheel speed sensor and the exciter ring;
• and
• identify wheel ends for which the wheel speed sensor signal amplitude is less than the predetermined minimum amplitude as having an airgap that is larger than a predetermined acceptable airgap size.

A system that facilitates performing an all-wheel marginally large airgap test (AWMLAT), comprising:

• an antilock brake system comprising
• a plurality of wheel speed sensors that respectively monitor a plurality of exciter rings;
• and
• an indicator light;
• and
• a processor configured to, upon test initiation, receive a signal from each of a plurality of wheel speed sensors on a vehicle, the signal being indicative of a exciter ring sensed by the sensor;
• wherein the processor is further configured to, for each wheel speed sensor:
• monitor exciter ring frequency to determine whether exciter ring frequency is within a predetermined frequency range;
• when exciter ring frequency is within the predetermined frequency range, measure wheel speed sensor signal peak amplitude;
• compare the measured wheel speed sensor signal peak amplitude to a predetermined minimum amplitude that represents the maximum allowable airgap between the wheel speed sensor and the exciter ring;
• and
• identify wheel ends for which the wheel speed sensor signal peak amplitude is less than the predetermined minimum amplitude as having an airgap that is larger than a predetermined acceptable airgap size.

An apparatus that facilitates performing an all-wheel marginally large airgap test (AWMLAT), comprising:

• receiving means for receiving a signal from each of a plurality of wheel speed sensors on a vehicle, the signal being indicative of a exciter ring sensed by the sensor;
• and
• for each wheel speed sensor:
• monitoring means for monitoring exciter ring frequency to determine whether exciter ring frequency is within a predetermined frequency range;
• measuring means for, when exciter ring frequency is within the predetermined frequency range, measuring wheel speed sensor signal peak amplitude;
• comparing means for comparing the measured wheel speed sensor signal amplitude to a predetermined minimum peak amplitude that represents the maximum allowable airgap between the wheel speed sensor and the exciter ring;
• and
• identifying means for identifying wheel ends for which the wheel speed sensor signal amplitude is less than the predetermined minimum peak amplitude as having an airgap that is larger than a predetermined acceptable airgap size.

A method for performing wheel-end marginally large airgap test (WEMLAT), comprising for each wheel on a vehicle:

• spinning a roller under the wheel for a predetermined number of revolutions within a preset speed range;
• measuring wheel speed sensor output during spinning;
• requesting status and results for all wheels;
• receiving status and result data;
• checking a predetermined status byte in the received data to determine the status of an airgap between the wheel speed sensor and an exciter ring coupled to the first wheel;
• and
• outputting to a user an indication of any wheels having an airgap that is larger than a predetermined allowable airgap threshold size.