US 5,749,984 AGranted

Tire monitoring system and method

AssigneeMichelin Recherche et Technique S.A.

InventorsNormam Walter Frey, Robert Jeffery Albertson

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Abstract

A method and system for monitoring and measuring the amount of deflection of a pneumatic tire wherein said monitoring system in the tire detects tire sidewall deflection by measuring the length of the tire contact patch area relative to the total circumference of the tire. The embedded sensor device generates a signal which varies as it passes through the tire contact patch within the tire on a moving vehicle. If the vehicle is moving at a constant speed, the ratio of time which the sensor spends inside the contact patch to the time the sensor spends outside the contact patch is proportional to tire deflection. Sensor electrical signals are digitized and counted to determine deflection, tire speed and the number of tire revolutions to improve performance of both the tire and the vehicle.

Claims17

Dependent claims

In a tire mounted on a wheel of a vehicle having a tread portion that contacts a ground surface over a tread contact surface during rolling of the tire under nominal operating conditions of vehicle load and speed, a tire monitoring system comprising:

a reference point on said tread contact surface of said tread portion defining a circumferential location on said tread portion;
a sensor device located within said tire associated with said reference point for generating first electrical signals when said reference point is included within said tread contact length and for generating second electrical signals when said reference point is not within said tread contact length;
an electronics package removed from said sensor device within said tire for energizing said sensor device and for receiving said first and said second electrical signals from said sensor device;
a digital monitoring device of said electronics package for interrogating said first and second electrical signals at a sampling frequency sufficient to obtain a first plurality of electrical pulses each revolution cycle of said tire and a second plurality of digital pulses each revolution cycle of the tire corresponding to said first and second electrical signals respectfully;
a digital logic circuit of said electronics package for determining a sum of the number of said first and second electrical pulses and an ratio of the number of said first electrical pulses to the number of said second electrical pulses each revolution cycle of the tire;
a memory device of said electronics package for storing said sum of electrical pulses and said ratio of said electrical pulses;
an operator display device for an operator of said vehicle to monitor performance of said tire;
digitized transceiver devices for transmitting and receiving a plurality of said sum values and a plurality of said ratio values, corresponding to a tire monitoring time, from said memory device of said tire to said operator display device of said vehicle;
and
an on-board computer associated with said operator display device for calculating and displaying at least tire deflection values using said plurality of ratio values, wherein said tire can be monitored for proper inflation pressures to provide a predetermined tire deflection.

7 more elements

A method for monitoring a tire mounted on a wheel of a vehicle having a tread portion that contacts a ground surface over a tread contact surface during rolling of the tire under nominal operating conditions of vehicle load and speed, said method comprising the steps of:

establishing a reference point on said tread contact surface which contacts a ground surface each revolution of said tire;
providing a sensor device within said tire associated with said reference point for generating electrical signals;
generating first electrical signals using said sensor device when said reference point is contacting said ground surface over a contact length;
generating second electrical signals using said sensor device when said reference point is not within said contact length;
providing an electrical package remote from said sensor device within said tire for energizing said sensor device and for receiving said first and second electrical signals from said sensor device;
interrogating said first and second electrical signals at a predetermined sampling frequency over a monitoring time using a digital monitoring device of said electrical package;
generating first and second electrical pulses from said digital monitoring device corresponding to said first and second electrical signals respectfully;
providing a digital counting logic circuit of said electrical package for generating the number of first and second electrical pulses respectively each revolution of the said tire using said sampling frequency;
determining a sum of the number of first and second electrical clock pulses each revolution of the tire using said logic circuit;
determining a ratio of the number of first electrical pulses to the number of second electrical pulses each revolution of the tire using said logic circuit;
storing said sum and said ratio in a pulse memory portion of said electronics package for each revolution of the tire;
transmitting a plurality of said sum and said ratio values for a plurality of revolutions, consistent with said tire monitoring time from said pulse memory portion to a receiver portion of an operator display device of said vehicle;
providing an on-board computer associated with said operator display device for calculating and displaying at least tire deflection values using said plurality of ratio values;
and
monitoring said tire deflection values using said operator display device and adjusting tire inflation pressure values for obtaining a predetermined tire deflection value.

12 more elements

Dependencies are inferred from the claim text.