Schrader | Date: 2013-04-10
A tyre monitor for mounting on a wheel rim, the tyre monitor comprising a housing having a first part (
Schrader | Date: 2013-08-22
Auto-location systems and methods of tire pressure monitoring sensor units arranged with a wheel of a vehicle detect a predetermined time (T1) when a wheel phase angle reaches angle of interest using a rim mounted or a tire mounted sensor. The systems and methods transmit a radio frequency message associated with a wheel phase angle indication. The wheel phase angle indication triggers wheel phase and/or speed data such as ABS data at the predetermined time (T1) to be stored. A correlation algorithm is executed to identify the specific location of a wheel based on the wheel phase and/or speed data at the predetermined time (T1). TPM sensor parameters from a tire pressure monitoring sensor unit are assigned to the specific location of the wheel based on a confidence interval width analysis of the ABS data at the predetermined (T1). The confidence interval width analysis identifies the specific location of the wheel whose ABS sensor shows a lowest confidence interval width as a result of a normal distribution pattern or similar pattern. The confidence interval width analysis may calculate a weighted cumulative confidence interval width for the ABS data which experience rollback events.
Schrader | Date: 2013-11-18
A method for determining change of direction of a vehicle includes steps of maintaining a rolling window of ABS data indicative of ABS tooth count and capturing a relevant rolling window of ABS data at the predetermined one-measurement point; storing the rolling window of the ABS data indicative of ABS tooth in a buffer; monitoring the ABS data and detecting a valid stop event which causes the rate of change of ABS tooth count to substantially decrement to zero; and monitoring the ABS data and detecting a valid move event which causes the rate of change of ABS tooth count to substantially increment from zero. The method also includes steps of determining a pre-stop phase relationship between at least two wheels based on the ABS tooth count stored in the buffer immediately prior to the valid stop event; determining a post-start phase relationship between at least two wheels based on the ABS tooth count stored in the buffer immediately subsequent to the valid move event; and correlating the pre-stop phase relationship and the post-start phase relationship to determine change of direction and confidence level.
Schrader | Date: 2014-11-25
An inflation device for a wheel with a pneumatic tire. A valve having a seat carried by a body and a head separates a chamber from an output connector. The head is movable within the chamber between a closed position wherein it is in abutment on the seat and an open position wherein it is separated from the seat so as to put the radial openings into communication with the output connector. The head is elastically held in the closed position against the seat so as to allow lifting of the head when the pressure in the output connector is greater than a predetermined threshold.
Schrader | Date: 2012-03-16
A wheel monitoring system that includes a tracking filter apparatus for tracking a signal that has a varying main frequency. The tracking filter apparatus has an adjustable filter and a filter controller arranged to measure the amplitude of the filtered signal and to compare amplitude against a reference value. The filter controller adjusts the cut off frequency of the filter if the measured amplitude differs from the reference value by an amount that exceeds a threshold value. The filter controller adjusts the cut off frequency such that the main frequency lies within the roll off region of the filters frequency response. The system may be used to track signals that are produced by shock sensors in a wheel mounted monitoring device.