Patent ID: 7249499

Claim:
A tire deflation warning system, comprising: a detecting means for detecting rotational velocities of wheels attached to a vehicle; judging means for judging a tire pneumatic pressure drop by determining a reduced pressure judging value that judges tire pneumatic pressure drop from a difference between sums of the rotational velocities of two pairs of said wheels which are diagonally disposed in the vehicle, determining a corrected reduced pressure judging value by multiplying said reduced pressure judging value by a weight coefficient that continuously varies according to the velocity of the vehicle, comparing the corrected reduced pressure judging value with a threshold value to produce a tentative judgement of whether or not there is a reduced pressure wheel; and when it is tentatively judged that a reduced pressure wheel is a driving wheel, said reduced pressure judging value is multiplied by said weight coefficient, which is larger than in the case when it is tentatively judged that a reduced pressure wheel is a driven wheel; and an indicator for providing an indication of tire pneumatic pressure drop.