Method and apparatus for determining tire condition using ideal gas law

An apparatus for determining a tire operating condition comprising:

• a tire-based sensor for sensing tire pressure and temperature and transmitting a signal indicative thereof;
• a vehicle ignition system;
• a vehicle-based receiver/controller for receiving the signal from the tire-based sensor and for detecting the state of the vehicle ignition system, said controller providing an error signal when the sensed tire pressure is less than a set threshold value Pset and resetting the error signal when the sensed tire pressure is greater than a reset threshold value Prst, the vehicle-based receiver/controller determining the set threshold value Pset and the reset threshold value Prst as a function of a calculated warm tire pressure value Pwarm, determining a mole value N of the tire pressure and adjusting the determined set threshold value Pset and the reset threshold value Prst in response to the vehicle ignition state and a change in the determined mole value N;
• and
• a display the displaying the error signal from the vehicle-based receiver/controller.