Method for processing information in a tire pressure monitoring system
First Claim
1. A method of measuring an undesired pressure drop in a tire of a vehicle and generating a warning signal responsive thereto, comprising the steps of:
- establishing a reference temperature;
determining at least one pressure warning threshold at the reference temperature;
measuring gauge pressure and gauge temperature within a tire cavity;
correcting the gauge pressure to a filtered pressure value at the reference temperature;
comparing the filtered pressure value against the pressure warning threshold;
generating a warning signal upon an undesired pressure drop in the tire.
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Abstract
A method of processing information in a tire pressure monitoring system includes the steps of: establishing a reference temperature; determining a pressure warning threshold at the reference temperature; measuring gauge pressure and gauge temperature within a tire cavity; correcting the gauge pressure to a filtered pressure value at the reference temperature using the Ideal Gas Law; and comparing the filtered pressure value against the pressure warning threshold to determine the necessity for a warning signal. In an advanced form of the invention, the method includes determining a pressure leak rate; predicting the time interval that the filtered pressure value will cross the pressure warning threshold at the leak rate and generating progressive warnings to the driver over the time interval. Fuzzy logic is used to quantify the probability of a warning state for each data point, allow for measurement error; and report the state of maximum probability to minimize the occurrence of false warning. A warning utility function is derived based upon a combination of the filtered pressure and leak rate.
76 Citations
20 Claims
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1. A method of measuring an undesired pressure drop in a tire of a vehicle and generating a warning signal responsive thereto, comprising the steps of:
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establishing a reference temperature;
determining at least one pressure warning threshold at the reference temperature;
measuring gauge pressure and gauge temperature within a tire cavity;
correcting the gauge pressure to a filtered pressure value at the reference temperature;
comparing the filtered pressure value against the pressure warning threshold;
generating a warning signal upon an undesired pressure drop in the tire. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of identifying a leak rate in a tire of a vehicle, comprising the steps of:
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establishing a reference temperature;
taking a finite number of sample data points of gauge pressure and gauge temperature within a tire cavity;
compensating the measured pressure data into filtered pressure values at the reference temperature;
applying a recursive linear least squares regression filter to the pressure data to estimate a pressure leak rate. - View Dependent Claims (12, 13, 14)
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15. A method of monitoring tire air pressure in a rolling vehicle, comprising:
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recording measured data pairs comprising values for pressure and temperature;
determining a characteristic curve for the measured data pairs;
determining filtered pressure values of the data pairs at a reference temperature utilizing the Ideal Gas Law; and
comparing the filtered pressure values of the data pairs against at least one pressure threshold value. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification