SYSTEM OF DETECTING TIRE INFORMATION

Abstract

A system of detecting tire information includes a measured value transmitter mounted in a tire of a vehicle and a controller provided in the body of the vehicle. The measured value transmitter includes an antenna, a resonator, the resonant frequency of which is varied in accordance with a temperature of the tire, and a resistive pressure sensor, the resistance of which is varied in accordance with a pressure in the tire. The controller transmits a signal for resonating the resonator and receives a signal having the resonant frequency of the resonator from the measured value transmitter. The controller calculates the temperature in the tire based on the signal having the resonant frequency. The controller calculates the pressure in the tire based on a signal level of the signal having the resonant frequency.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.

FIG. 1 is a schematic illustrating an example of a transponder circuit for a system of detecting tire information;

FIG. 2 is a graph illustrating a difference between the resonant frequency extracted from a signal received from the transponder and the frequency of an oscillation signal from a controller;

FIG. 3 is a graph illustrating the relationship between a resistance in a pressure sensor in the transponder and a predetermined-level reaching time;

FIG. 4 is a schematic illustrating an example of a controller circuit for a system of detecting tire information in the related art; and

FIG. 5 is a schematic illustrating an example of a transponder circuit for the system of detecting tire information in the related art.

Claims

1. A system of detecting tire information, comprising: a measured value transmitter mounted in a tire of a vehicle; anda controller provided in a body of the vehicle,wherein the measured value transmitter includes an antenna, a resonator, a resonant frequency of which is varied in accordance with a temperature of the tire, and a resistive pressure sensor, a resistance of which is varied in accordance with a pressure in the tire, andwherein the controller is operable to transmit a signal for resonating the resonator and receive a signal having the resonant frequency of the resonator from the measured value transmitter, and the controller is operable to calculate the temperature in the tire based on the signal having the resonant frequency and calculate the pressure in the tire based on a signal level of the signal having the resonant frequency.

2. The system of claim 1, wherein the resonator and the resistive pressure sensor are connected in parallel to an input and output end of the antenna in the measured value transmitter.

3. The system of claim 1, wherein the controller is operable to calculate the pressure in the tire based on a time required for attenuation of the signal level of the signal having the resonant frequency to reach a predetermined level.

4. The system of claim 1, wherein the controller is operable to calculate the temperature in the tire based on a difference between a frequency of the signal for resonating the resonator and the resonant frequency extracted from the signal received from the measured value transmitter.

5. The system of claim 1, wherein the resistive pressure sensor is a piezoresistive pressure sensor.

6. The system of claim 1, wherein the resistive pressure sensor is a strain gauge.