Patent ID: 6575023
Filing Date: 2003-06-10
Classification: B60C

Abstract:
A tire air pressure determining apparatus comprising:wheel speed pulse generating means that generates a pulse every time wheels of a vehicle rotate by a predetermined angle and that is provided for each of the wheels; vehicle speed detecting means that detects a speed of the vehicle as a vehicle speed; variable value calculating means that calculates a variable value for making determination of a tire air pressure based on the pulse generated by the wheel speed pulse generating means when a predetermined condition is fulfilled; reference variable value storing means that stores the calculated variable value as a reference variable value; reference vehicle speed storing means that stores the vehicle speed at the time when the reference variable value is calculated as a reference vehicle speed associated with the reference variable value; vehicle speed condition determining means that determines whether or not the vehicle speed at the time when the variable value calculating means newly calculates the variable value is within a predetermined vehicle speed range determined by the reference vehicle speed; and air pressure determining means that determines, based on a difference between the newly calculated variable value and the reference variable value associated with the reference vehicle speed, whether or not the tire air pressure is normal, if it is determined that the vehicle speed at the time when the variable value calculating means newly calculates the variable value is within the predetermined vehicle speed range determined by the reference vehicle speed.