Patent ID: 7800487

Claim:
A method for alarming decrease in tire air-pressure that detects decrease in tire air-pressure using a judgment value obtained based on rotational wheel speeds obtained from tires loaded on a vehicle, the method comprising the following steps carried out using a computer: detecting the rotational wheel speeds of respective tires when the vehicle turns round a corner, calculating a vehicle speed from the rotational wheel speeds of respective tires, detecting a yaw rate of the vehicle, detecting acceleration to a lateral direction by a lateral directional acceleration sensor, estimating a bank angle at the corner during turning using the yaw rate, the vehicle speed and the lateral directional acceleration of the vehicle, calculating the judgment value from the rotational wheel speeds of respective tires, preventing erroneous judgment occurring during turning round the corner with the bank angle by setting a threshold based on the estimated bank angle, and generating an alarm when the judgment value exceeds the threshold.