Method of detecting a deflated tire on a vehicle
First Claim
1. A method of detecting a partially deflated tire on a vehicle having four tires each mounted on a wheel, each wheel having a signal generator for producing a series of digital signals or pulses spaced apart by equal increments from angular rotation of the respective tire and wheel assembly, the steps comprising:
- calculating vehicle speed from one of the series of signals or pulses produced by the signal generator for a reference tire selected from among the four tires;
selecting an appropriate interval for deflation detection from the calculated vehicle speed;
measuring a speed of rotation signal for each of the four wheels during said interval;
storing the measured speeds;
repeating the measuring step for at least three consecutive successive equal intervals and storing the results of each repetition;
averaging the stored speeds to produce an average speed signal for each wheel;
processing the four signals in a processing unit which subtracts the sum of the signals from one pair of diagonally opposite wheels from the sum of the signals from the other pair of diagonally opposite wheels;
sensing when the magnitude of the result of said processing steps is in the range of between 0.05% and 0.6% of the mean of the two sums; and
when the mean of the sums in within the prescribed range, operating a warning device to indicate that a tire is partially or completely deflated.
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Accused Products
Abstract
A method and apparatus for detecting a partially deflated tire on a vehicle having four tires each mounted on a wheel. Each wheel being provided with a signal generator for producing a series of digital signals or pulses spaced apart by equal increments by angular rotation of the respective tire and wheel assembly characterized by calculating from one of the series of signals reflective of the vehicle speed. The method includes selecting an appropriate interval for deflation detection, measuring the speed of rotation for each of the four wheels, storing the speeds found, repeating the measuring step for at least three consecutive successive equal intervals, averaging the speeds to produce an average speed signal for each wheel, processing the four signals in a processing unit which subtracts the sum of the signals from one pair of diagonally opposite wheels from the sum of the signal from the other pair of diagonally opposite wheels, sensing when the magnitude of the result is between 0.05% and 0.6% of the mean of the two sums and, if sensed within the recited range, operating a warning device to indicate that a tire is partially or completely deflated.
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Citations
14 Claims
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1. A method of detecting a partially deflated tire on a vehicle having four tires each mounted on a wheel, each wheel having a signal generator for producing a series of digital signals or pulses spaced apart by equal increments from angular rotation of the respective tire and wheel assembly, the steps comprising:
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calculating vehicle speed from one of the series of signals or pulses produced by the signal generator for a reference tire selected from among the four tires; selecting an appropriate interval for deflation detection from the calculated vehicle speed; measuring a speed of rotation signal for each of the four wheels during said interval; storing the measured speeds; repeating the measuring step for at least three consecutive successive equal intervals and storing the results of each repetition; averaging the stored speeds to produce an average speed signal for each wheel; processing the four signals in a processing unit which subtracts the sum of the signals from one pair of diagonally opposite wheels from the sum of the signals from the other pair of diagonally opposite wheels; sensing when the magnitude of the result of said processing steps is in the range of between 0.05% and 0.6% of the mean of the two sums; and when the mean of the sums in within the prescribed range, operating a warning device to indicate that a tire is partially or completely deflated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for detecting a partially deflated tire on a vehicle having four tires each mounted on a wheel, each wheel having a signal generator for producing a series of digital signals or pulses spaced apart by equal increments from angular rotation of the respective tire and wheel assembly, the apparatus comprising:
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means for calculating vehicle speed from one of the series of signals produced by the signal generator for a reference tire selected from among the four tires; means for selecting an appropriate interval for deflation detection from the calculated vehicle speed; means for measuring a signal representing the rotational speed for each of the four wheels during said interval; means for storing the measured speeds; means for averaging the stored speeds to produce an average speed signal for each wheel; means for processing the four signals which subtracts the sum of the signals from one pair of diagonally opposite wheels from the sum of the signals from the other pair of diagonally opposite wheels; means for sensing when the magnitude of the result produced by said processing means is in the range of between 0.05% and 0.6% of the mean of the two sums for signaling that a tire is partially or completely deflated when the mean of the sums is within the prescribed range. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification