Apparatus and method for sensing a condition of a vehicle tire

• US 6,518,875 B2
• Filed: 06/19/2001
• Issued: 02/11/2003
• Est. Priority Date: 12/20/1999
• Status: Expired due to Term

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: DeZorzi, Timothy
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): PREVIL, DANIEL
• Application Number:
  US09/885,564
• Publication Number:
  US 20020075144A1
• Time in Patent Office: 602 Days
• Field of Search: 340/442, 340/438, 340/445, 340/447, 340/531, 340/539, 340/425.5, 340/448, 340/444, 340/572.4, 340/825.69
• US Class Current: 340/442
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver

Abstract

A tire condition sensor module (14) for a vehicle (10) comprises at least one actuatable tire condition sensor (78, 84, 88) for sensing a tire condition of an associated vehicle tire (20) and a motion detector (32) for detecting movement of the associated vehicle tire (20). The module (14) further includes a transmitter (44) for transmitting a tire condition indicating signal having a characteristic based on the sensed tire condition signal. A controller (74) controls actuation of the tire condition sensor (78, 84, 88) and the transmitter (44). The controller (74) is continuously energized and has first and second operating modes. The controller (74) operates in the first operating mode when movement of the associated tire (20) is greater than a predetermined value and operates in the second operating mode when movement of the associated tire (20) is less than the predetermined value.

Claims

1. A tire condition sensor module for a vehicle comprising:

a source of electrical energy;

at least one actuatable tire condition sensor operative to sense a tire condition of an associated vehicle tire and to provide a tire condition signal indicative of the condition sensed;

a motion detector operative to detect movement of the associated vehicle tire and to provide a motion signal having a characteristic indicating movement of the associated vehicle tire;

a transmitter operative to transmit a tire condition indicating signal having a characteristic based on the tire condition signal; and

a controller for controlling actuation of said at least one tire condition sensor and for controlling said transmitter, said controller being continuously energized from said source of electrical energy and having first and second operating modes, said controller (i) operating in said first operating mode when the motion signal indicates movement of the associated tire that is greater than a predetermined value and (ii) operating in said second operating mode when the motion signal indicates movement of the associated tire that is less than the predetermined value,

said controller intermittently actuating said at least one tire condition sensor to sense the tire condition and controlling said transmitter to periodically transmit the tire condition indicating signal when said controller is operating in said first operating mode, and said controller intermittently actuating said tire condition sensor to sense the tire condition and controlling said transmitter to transmit the tire condition indicating signal only if said controller determines that the tire condition signal indicates that the sensed tire condition is indicative of an alert condition when said controller is operating in said second operating mode.

2. The module as set forth in claim 1 wherein said controller, when operating in said second operating mode, actuates said tire condition sensor at a rate that is less than a rate at which said controller actuates said tire condition sensor when operating in said first operating mode.

3. The module as set forth in claim 1 wherein said controller, when operating in said first operating mode, increases a rate of transmission of the tire condition indicating signal upon a determined difference of at least a predetermined amount between the sensed tire condition and a reference tire condition.

4. The module as set forth in claim 3 wherein the reference tire condition is an immediately preceding transmitted tire condition indicating signal.

5. The module as set forth in claim 1 wherein said controller controls a time period between and a predetermined number of transmissions of said transmitter.

6. The module as set forth in claim 1 wherein said controller, when in said second operating mode, controls said transmitter to periodically transmit the tire condition indicating signal for a predetermined time period when the tire condition signal indicates that the sensed tire condition is indicative of the alert condition.

7. The module as set forth in claim 1 wherein said controller, when in said second operating mode, controls said transmitter to transmit the tire condition indicating signal a predetermined number of times when the tire condition signal indicates that the sensed tire condition is indicative of the alert condition.

8. The module as set forth in claim 1 further including an actuatable control switch electrically connected to said source of electrical energy and said tire condition sensor, said controller controlling actuation of said at least one tire condition sensor by controlling said actuatable control switch.

9. The module as set forth in claim 1 wherein said tire condition is air pressure.

10. The module as set forth in claim 9 wherein said alert condition occurs when the sensed air pressure in the associated vehicle tire is less than a predetermined value.

11. The module as set forth in claim 9 wherein said alert condition occurs when the sensed air pressure in the associated tire drops by a predetermined value.

12. A method for monitoring a condition of a vehicle tire, said method comprising the steps of:

continuously energizing a controller from a source of electrical energy;

detecting movement of the vehicle tire;

providing a motion signal in response to detected movement to said controller;

determining whether the motion signal indicates movement of the vehicle tire;

operating the controller in a first operating mode when the motion signal indicates movement of the vehicle tire that is greater than a predetermined value and operating said controller in a second operating mode when the motion signal indicates movement of the vehicle tire that is less than the predetermined value;

intermittently sensing a condition of the vehicle tire on a continuing basis and providing a tire condition signal indicative of the condition sensed to said controller;

periodically transmitting a tire condition indicating signal having a characteristic based on the tire condition signal when said controller is operating in said first operating mode; and

transmitting the tire condition indicating signal only if said controller determines that the tire condition signal indicates that the sensed tire condition is indicative of an alert condition when said controller is operating in said second operating mode.

13. The method as set forth in claim 12 wherein the step of intermittently actuating said tire condition sensor further includes the steps of:

actuating said tire condition sensor at a first rate when said controller is operating in said first mode of operation, and

actuating said tire condition sensor at a second rate, that is less than the first rate, when said controller is operating in said second mode of operation.

14. The method as set forth in claim 12 wherein the step of periodically transmitting the tire condition indicating signal further includes the steps of:

storing a reference value for a predetermined tire condition;

comparing a value of the tire condition signal with the reference value; and

increasing a rate of transmission of said tire condition indicating signal, when the controller is operating in said first operating mode and upon determining a difference of at least a predetermined amount between the sensed tire condition and the reference value.

15. The method as set forth in claim 12 wherein the step of intermittently actuating said tire condition sensor further includes the step of varying a rate of actuation of said tire condition sensor in response to the motion signal.

16. The method as set forth in claim 12 wherein the step of intermittently sensing the condition of the tire includes the step of intermittently actuating a control switch to intermittently provide electrical energy to a tire condition sensor.

17. The method as set forth in claim 12 wherein the step of intermittently sensing a condition of the vehicle tire includes the step of sensing air pressure in the tire.