A system for the detection of a pressure drop in a tire comprising a tire air pressure sensor, a tire temperature sensor and an evaluating unit. The evaluating unit converts the measured air pressure values and temperature values into temperature compensated air pressure values and produces an alarm signal when the temporal fluctuation exceeds an air pressure fluctuation threshold value. The evaluating unit decreases the air pressure threshold value with increasing deviation from the measured temperature compensated air pressure value of a predetermined temperature compensated air pressure reference value. At least one further sensor may be provided for measuring a parameter which influences the air pressure in the tire whereby the evaluating unit corrects the measured and, regarding to the production of an alarm signal, evaluated air pressure according to this parameter.
An installation structure of an electronic component for a tire, where the installation structure protects the electronic component from heat produced by a tire and a braking device and enables accurate information about the inside of the tire to be obtained without being affected by the heat sources. In the installation structure, an electronic component housed in a case is installed at an arbitrary installation in the air chamber of a tire and a heat-insulating structure is interposed between the electronic components and the installation position.
A sensor detects values of inflation pressure of a tire of a vehicle one after another. A controller calculates, from the values of the tire inflation pressure, a deflation rate at which the tire is deflating per unit time. When the deflation rate is higher than a first predetermined value, the controller judges that the tire is suddenly punctuated. When the deflation rate is not higher than the first predetermined value but is higher than a second predetermined value, the controller judges that the tire is deteriorated. When the deflation rate is not higher than the second predetermined value, the controller judges that compressed air is naturally leaked from the tire. An alarm unit gives an alarm indicating punctuation or deterioration of the tire or natural air leaking in response to the judgment of the controller.
A method of detecting a rapid leak of gas contained in an automobile tire based on periodic measurements of a pressure Pa and a temperature Ta of the gas. The method includes determining a reference pressure Pcref, calculating an alarm threshold pressure Sref from the reference pressure Pcref, calculating a temperature-compensated pressure Pc at each measurement acquisition period, and comparing the compensated pressure Pc with the alarm threshold pressure Sref, wherein the leak is detected if the compensated pressure Pc is less than the alarm threshold pressure Sref.
