Transmitter and transmitting method of tire air pressure monitoring apparatus

• US 6,450,021 B1
• Filed: 11/02/1999
• Issued: 09/17/2002
• Est. Priority Date: 10/12/1999
• Status: Expired due to Term

• Current Assignee: Pacific Industrial Company Limited
• Original Assignee: Pacific Industrial Company Limited
• Inventors: Katou, Michiya, Momose, Akira
• Primary Examiner(s): PATEL, HARSHAD R
• Application Number:
  US09/432,193
• Time in Patent Office: 1,050 Days
• Field of Search: 731/465, 731/462, 731/468, 731/463, 731/46, 340/442, 340/445, 340/447, 340/443, 116/34.R, 702/138
• US Class Current: 73/146.5
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0455 Transmission control of wireless signals
• CPC Class Codes: B60C 23/0462 Structure of transmission protocol
• CPC Class Codes: B60C 23/0474 Measurement control, e.g. setting measurement rate or calibrating of sensors; Further processing of measured values, e.g. filtering, compensating or slope monitoring

Abstract

A tire air monitoring apparatus includes transmitters for wirelessly transmitting data regarding the inner pressure of tires and a receiver for receiving the data transmitted by the transmitters. Each transmitter is powered by a battery. Each transmitter includes a pressure sensor, which measures the inner pressure of the tire at predetermined measuring intervals. Each transmitter periodically and wirelessly transmits data every time the pressure sensor has taken a measurement a predetermined number of times. When the tire pressure changes by an amount that is equal to or greater than a predetermined upper limit value during a predetermined judging time, the transmitter performs an early data transmission. Therefore, an abnormality in the tire pressure is immediately communicated to a driver, and battery strength is conserved.

Claims

1. A battery-powered transmitter for wirelessly transmitting data regarding an inner pressure of a vehicle tire, the transmitter comprising:

a pressure sensor for measuring the inner pressure of the tire;

a transmission circuit for wirelessly transmitting data representing the measured tire pressure; and

a controller for controlling the transmission circuit to periodically transmit the data at predetermined transmission intervals, wherein, when the tire pressure changes by an amount that is equal to or greater than a first predetermined upper limit value during a first predetermined judging time, the controller controls the transmission circuit to transmit the data earlier than the next data transmission that would take place according to the periodic transmission intervals, and wherein, when the tire pressure changes by an amount that is equal to or greater than a second predetermined upper limit value during a second judging time, the controller controls the transmission circuit to transmit the data earlier than the next data transmission that would take place according to the periodic transmission intervals, wherein second judging time is an integer multiple of the first judging time and wherein the integer multiple is two or more.

2. The transmitter according to claim 1, wherein the controller controls the pressure sensor to measure the tire pressure at predetermined measuring intervals, and wherein the length of the transmission interval is an integer multiple of the length of one of the measuring intervals.

3. The transmitter according to claim 2, wherein the length of the first judging time is equal to the length of one of the measuring intervals or an integer multiple of the length of one of the measuring intervals.

4. The transmitter according to claim 1, wherein the second upper limit value is equal to the first upper limit value.

5. The transmitter according to claim 1, wherein the first and second upper limit values are greater than normal fluctuations of the tire pressure that would be expected during the corresponding judging time due to movement of the vehicle.

6. The transmitter according to claim 1, further comprising a temperature sensor for measuring the inner temperature of the tire, and wherein, when the measured inner temperature of the tire is equal to or higher than a predetermined value, the controller controls the transmission circuit to transmit the data earlier than the next data transmission that would take place according to the periodic transmission intervals.

7. The transmitter according to claim 6, wherein the controller controls the pressure sensor and the temperature sensor to take a measurement at predetermined measuring intervals, and wherein the length of the transmission interval is an integer multiple of the length of one of the measuring intervals.

8. A battery-powered transmitter for wirelessly transmitting data regarding an inner pressure of a vehicle tire, the transmitter comprising:

a pressure sensor for measuring the inner pressure of the tire;

a transmission circuit for wirelessly transmitting data containing the measured tire pressure; and

a controller for controlling the pressure sensor to measure the tire pressure at predetermined measuring intervals, wherein the controller controls the transmission circuit to periodically and wirelessly transmit the data at regular transmission intervals, which occur every time the pressure sensor has taken a predetermined number of measurements, wherein, when the tire pressure changes by an amount that is equal to or greater than a first predetermined upper limit value during a first predetermined judging time, the controller controls the transmission circuit to transmit the data earlier than the next data transmission that would take place according to the regular transmission intervals, wherein the first judging time is equal to the measuring interval or an integer multiple of the measuring interval, and wherein, when the tire pressure changes by an amount that is equal to or greater than a second predetermined upper limit value during a second judging time, the controller controls the transmission circuit to transmit the data earlier than the next data transmission that would take place according to the regular transmission intervals, wherein the second judging time is an integer multiple of the first judging time and wherein the integer multiple is two or more.

9. The transmitter according to claim 8, wherein the second upper limit value is equal to the first upper limit value.

10. The transmitter according to claim 8, wherein the first and second upper limit values are greater than normal fluctuations of the tire pressure that would be expected during the corresponding judging time due to movement of the vehicle.

11. The transmitter according to claim 8, further comprising a temperature sensor for measuring the inner temperature of the tire, and wherein, when the measured inner temperature of the tire is equal to or higher than a predetermined value, the controller controls the transmission circuit to transmit the data earlier than the next data transmission that would take place according to the regular transmission intervals.

12. The transmitter according to claim 11, wherein the controller controls the temperature sensor to take a measurement at every measuring interval.

13. A method for wirelessly transmitting data regarding an inner pressure of a vehicle tire by a battery-powered transmitter, the method comprising:

periodically measuring the inner pressure of the tire at regular measuring intervals;

periodically and wirelessly transmitting data representing the measured tire pressure at regular transmission intervals;

periodically determining a tire pressure change;

comparing the tire pressure change to a first predetermined upper limit value during a first predetermined judging time;

performing a first early wireless transmission before the next data transmission would take place according to the regular transmission intervals, when the tire pressure change is equal to or greater than the first predetermined upper limit value during the first predetermined judging time;

comparing the tire pressure change to a second predetermined upper limit value during a second judging time;

performing a second early wireless transmission before the next data transmission would take place according to the regular transmission intervals, when the tire pressure change is equal to or greater than the second predetermined upper limit value during the second judging time, wherein the second judging time is an integer multiple of the first judging time.

14. The method according to claim 13, wherein the transmission interval is an integer multiple of the measuring interval.