Patent ID: 8606535

Claim:
Method for determining air loss from a vehicle tire utilizing a tire parameter monitoring apparatus having temperature and pressure measuring sensors, comprising the steps of: measuring a regional temperature value and a pressure value to establish a measured regional temperature value and a measured pressure value, establishing a reference isochore for a wheel/tire structure wherein the reference isochore includes a correlation between reference isochore pressure and reference isochore mean gas temperature for a fixed volume of gas in the wheel/tire structure, establishing a measured isochore correlating measured temperatures and measured pressures based upon at least two measured regional temperature values and measured pressure value, establishing a set of calculated offset correction temperature values representing differences between each measured regional temperature value along the measured isochore and reference isochore mean gas temperature value along the reference isochore, for various corresponding pressures, calculating a calculated isochore mean gas temperature value by applying the corresponding offset correction temperature value to a corresponding measured regional temperature value, using the measured isochore to determine a calculated isochore pressure value among a plurality of calculated isochore pressure values at a point along said measured isochore corresponding with said calculated isochore mean gas temperature value, comparing the measured pressure value with the calculated isochore pressure value, further comprising the steps of establishing a state of thermal balance for the wheel/tire structure, and creating at least one new set of calculated offset correction temperature values while a determined difference between the measured pressure values along the measured isochore and calculated reference isochore pressure values is increasing, wherein a loss of gas from the tire is indicated by said measured pressure value being less than said calculated isochore pressure value.