Electronic tire management system

A system for measuring a tire parameter comprising:

• a tire tag disposed inside of a vehicle tire, the tire tag including:
• a sensor for measuring one or more tire parameters;
• a microprocessor coupled to the sensor for activating the sensor on a first periodic basis;
• a memory in the microprocessor for storing the one or more tire parameters;
• and
• a receiver coupled to the microprocessor, the microprocessor periodically partially awakening to examine, on a second periodic basis, a transmission and to at least partially identify the transmission as an interrogation signal from a reader/transceiver (RT) at the second location;
• a search mode wherein the microprocessor partially awakens to further examine the partially identified interrogation signal and verify that the partially identified interrogation signal is a valid interrogation signal;
• a transmitter coupled to the microprocessor;
• and
• an interrogation mode wherein the microprocessor fully awakens and responds to the valid interrogation signal, via the transmitter, by at least transmitting the last stored data signal representing the measured parameter.

A tire tag comprising:

• a sensor for measuring at least one tire parameter and generating a data signal representing the measured parameter;
• a microprocessor for causing the tire tag to enter a deep sleep mode in which a minimum number of electrical components are powered to conserve battery power;
• the microprocessor, on a periodic basis, causing the tire tag to enter a lucid sleep mode in which certain of the electrical components are activated to cause the sensor to measure and store the at least one tire parameter;
• and
• the microprocessor periodically partially awakening and looking for a forward link transmission and, if detected, causing the tire tag to determine whether the forward link transmission is a valid interrogation signal and, if so, causing the tire tag to enter an interrogation mode where the microprocessor activates all necessary electrical components to receive, process and respond to the valid interrogation signal.

A system for measuring a parameter of a device at a first location comprising:

• a sensor for measuring the device parameter and generating a data signal representing the measured parameter;
• a memory in the microprocessor for storing the generated data signal representing the measured parameter;
• a microprocessor coupled to the sensor for activating the sensor on a first periodic basis to measure the device parameter, the microprocessor comparing the measured parameter with one or more parameter thresholds and generating an alarm signal if the measured parameter is outside of the one or more parameter thresholds;
• and
• a transmitter coupled to the microprocessor for transmitting the alarm signal on a second periodic basis to a remote reader/transceiver (RT) without external activation.

An electronic tire management system (ETMS) comprising:

• a sensor for measuring a tire parameter and generating a data signal representing the measured tire parameter;
• a memory for storing one or more parameter thresholds;
• a tag transmitter for transmitting an RF signal;
• a microprocessor coupled to the sensor and the transmitter, the microprocessor activating the sensor at periodic intervals to measure the tire parameter, comparing the measured tire parameter with the one or more stored parameter thresholds, generating an alert signal if the measured parameter is outside of the one or more parameter thresholds, and, in response to the alert signal, causing the transmitter to transmit an alarm signal that indicates that the tire parameter is outside of the one or more parameter thresholds;
• and
• a printed circuit board mounted in the tire and including the sensor, the memory, the tag transmitter, and the microprocessor.

A process for electronic tire management comprising:

• mounting a tire tag on the inside of a tire;
• causing the tire tag to enter a deep sleep mode;
• periodically causing the tire tag to partially awaken on a first periodic basis to measure one or more parameters of the tire;
• storing the measured parameters;
• returning the tire tag to the deep sleep mode;
• and
• periodically causing the tire tag to partially awaken to determine, on a second periodic basis, if a received transmission is a valid interrogation signal and, if so, fully awakening and responding to the valid interrogation signal, via the transmitter, by at least transmitting the measured parameters to a remote reader/transceiver (RT).

A process for electronically monitoring tire parameters with a tire tag, the process comprising:

• sleeping in a deep sleep mode for a predetermined period of time;
• awakening to a lucid sleep mode to detect if a transmission is likely a forward link packet from a remote reader/transceiver (RT);
• entering a search mode to determine if the transmission is a valid forward link packet;
• entering an interrogation mode if a valid forward link packet is detected and responding to the valid forward link packet;
• and
• returning to the deep sleep mode.

A method for electronically monitoring tire parameters with a tire tag, the method comprising:

• causing the tire tag to enter a deep sleep mode to conserve power;
• and
• automatically awakening the tire tag from the deep sleep mode on a first periodic basis to measure and store the tire parameters;
• automatically awakening the tire tag from the deep sleep mode on a second periodic basis to detect if a transmission is a valid forward link packet from a remote reader/transceiver (RT) and, if so, responding to the valid forward link packet;
• and
• returning the tire tag to the deep sleep mode.

A tire tag comprising:

• a microprocessor programmed to:
• store the cold fill temperature of a vehicle tire;
• measure the hot inflation pressure and temperature of the vehicle tire during operation of the tire;
• calculate an equivalent cold pressure of the tire using the ideal gas equation:
• PV=nRT
• where
• P=pressure exerted by the gas in the tire (a variable);
• V=volume of the chamber containing the gas (essentially a constant);
• n=number of moles of gas contained within the tire (a constant);
• R=a constant specific to the gas contained within the tire;
• T=temperature of the gas contained within the tire (a variable);
• and
• T1/P1=T2/P2
• where
• P1=pressure at time t1 (cold fill reference pressure)
• P2=pressure at time t2 (current hot pressure)
• T1=temperature at time t1 (cold fill reference temperature)
• T2=temperature at time t2 (current hot temperature);
• and
• compare the calculated equivalent cold pressure with a stored Target Cold Fill Inflation Pressure specified by the manufacturer of the tire to determine if the tire is properly inflated during operation.