System and method for monitoring a pneumatic tire

• US 5,585,554 A
• Filed: 06/07/1995
• Issued: 12/17/1996
• Est. Priority Date: 10/31/1994
• Status: Expired due to Term

• Current Assignee: Helene Laliberte, Michael Handfield
• Original Assignee: Helene Laliberte, Michael Handfield
• Inventors: Handfield, Michael, Laliberte, Helene
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Dombroske, George M.
• Application Number:
  US08/484,306
• Time in Patent Office: 559 Days
• Field of Search: 73/146.5, 73/700, 73/714, 73/723, 73/728, 73/733, 73/753, 73/754, 73/755, 73/756, 455/336, 330/294
• 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 23/0433 Radio signals
• CPC Class Codes: B60C 23/0462 Structure of transmission protocol
• CPC Class Codes: B60C 23/0494 Valve stem attachments positioned inside the tyre chamber
• CPC Class Codes: B60C 23/0496 Valve stem attachments positioned outside of the tyre chamber
• CPC Class Codes: G06K 19/07764 the adhering arrangement making the record carrier attachable to a tire tire temperature or pressur control arrangements, see B60C23/00
• CPC Class Codes: H01Q 1/2241 used in or for vehicle tyres

Abstract

A pneumatic tire monitoring system is disclosed which provides a pressure sensor/transponder unit for each pneumatic tire of a vehicle to monitor tire pressure. A coded signal transmitted from each transponder unit is received by a multi-purpose receiver which may provide information to the vehicle operator or to other vehicle systems and subsystems. Each transponder unit is characterized by ultra low power consumption to extend the useful battery life. The transponder units may be mounted within the vehicle tires, or externally mounted. Impedance matching circuitry allows the use of the wheel rims with the transmitting antenna so as to avoid doppler shift induced by the rotating antenna and frequency drift induced by capacitive coupling.

Claims

1. A super-regenerative receiver with compensation, the receiver comprising:

an antenna for receiving a transmitted electromagnetic signal;

a two-stage common-base amplifier having an input and an output, the input being operatively associated with the antenna;

a transistor having a base, an emitter, and a collector, the base being capacitively coupled to the output of the amplifier;

a first inductor connected across the base and the collector of the transistor;

a second inductor connected to the base of the transistor and capacitively coupled to the first inductor, the first and second inductors being inductively coupled out of phase so as to improve frequency stability of the system.

2. The receiver of claim 1 wherein the receiver is tuned to detect pulses at a nominal frequency of about 300 MHz and 90 MHz.

3. The receiver of claim 1 wherein the two-stage common-base amplifier comprises:

a first low-noise transistor having a base, an emitter, and a collector, the base being coupled to the antenna via a capacitor and a third inductor and the emitter being connected to ground; and

a second low-noise transistor having a base, an emitter, and a collector, the base being capacitively coupled to the collector of the first low-noise transistor, the emitter being coupled to ground, and the collector being coupled to the output of the amplifier.

4. The receiver of claim 1 wherein the first and second inductors have a nominal value of about 20 mH.

5. The receiver of claim 1 wherein the transistor comprises a low-noise transistor.

6. The receiver of claim 1 further comprising:

a third inductor connected to the emitter of the transistor; and

a capacitor having a first end coupled to the base of the transistor and a second end coupled to the third inductor.

7. The receiver of claim 6 wherein the third inductor and the capacitor are selected to produce a quenching frequency of about 100 KHz.