System and method for indirect indication of tire pressure loss
First Claim
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1. A method of indirect tire pressure monitoring for indicating when a pneumatic tire on a wheel at one end of a motor vehicle axle is underpressurized relative to a pneumatic tire on a wheel at an opposite end of the axle while the vehicle is being driven on a road surface, the method comprising:
- repeatedly calculating difference between a current measurement of effective radius of each tire relative to a reference value for effective radius of the same tire;
processing the calculated differences for each tire to calculate a value of a first-order derivative of effective radius of the same tire and comparing the calculated value of the first-order derivative of effective radius of one tire to the calculated value of the first-order derivative of effective radius of the other tire; and
when the comparison of the calculated values of the first-order derivatives of the respective tires discloses that the value of one of the first-order derivatives differs from that of the other of the first-order derivatives by more than a defined amount, using that disclosure to determine if an alert for indicating that one tire is too underpressurized relative to the other should be issued.
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Abstract
A method of indirect tire pressure monitoring for indicating when a pneumatic tire on a wheel at one end of a motor vehicle axle is underpressurized relative to a pneumatic tire on a wheel at an opposite end of the axle while the vehicle is being driven on a road surface. ABS wheel sensors are used as inputs to a devoted processor for indirect tire pressure monitoring.
12 Citations
15 Claims
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1. A method of indirect tire pressure monitoring for indicating when a pneumatic tire on a wheel at one end of a motor vehicle axle is underpressurized relative to a pneumatic tire on a wheel at an opposite end of the axle while the vehicle is being driven on a road surface, the method comprising:
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repeatedly calculating difference between a current measurement of effective radius of each tire relative to a reference value for effective radius of the same tire; processing the calculated differences for each tire to calculate a value of a first-order derivative of effective radius of the same tire and comparing the calculated value of the first-order derivative of effective radius of one tire to the calculated value of the first-order derivative of effective radius of the other tire; and when the comparison of the calculated values of the first-order derivatives of the respective tires discloses that the value of one of the first-order derivatives differs from that of the other of the first-order derivatives by more than a defined amount, using that disclosure to determine if an alert for indicating that one tire is too underpressurized relative to the other should be issued. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An indirect tire pressure monitoring system for indicating when a pneumatic tire on a wheel at one end of a motor vehicle axle is underpressurized relative to a pneumatic tire on a wheel at an opposite end of the axle while the vehicle is being driven on a road surface, the system comprising:
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a respective sensor at each wheel that supplies the same data to an ABS system (antilock brake system) of the vehicle and to a devoted processor for indirect tire pressure monitoring; and wherein the devoted processor is arranged to repeatedly execute an algorithm for calculating difference between a current measurement of effective radius of each tire relative to a reference value for effective radius of the same tire, to process the calculated differences for each tire to calculate a value of a first-order derivative of effective radius of the same tire and compare the calculated value of the first-order derivative of effective radius of one tire to the calculated value of the first-order derivative of effective radius of the other tire, and when the comparison of the calculated values of the first-order derivatives of the respective tires discloses that the value of one of the first-order derivatives differs from that of the other of the first-order derivatives by more than a defined amount, using that disclosure to determine if an alert for indicating that one tire is too underpressurized relative to the other should be issued. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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Specification