Patent ID: 7991523

Claim:
A method for indirect tire pressure monitoring, the method comprising: learning test variables (DIAG, SIDE, and AXLE) where DIAG as for the wheel rotation of the two diagonally opposite wheel, SIDE as for the wheel rotation on the side of vehicle, AXLE as for the wheel rotation of the one axle, which describe rotational movements of wheels learning at least one torsion natural frequency fp for at least one tire from oscillation behavior of individual tires wherein during the learning (1) initially only a rough position of the torsion natural frequency fp is determined, and (2) subsequently a range is defined around the position of the torsion natural frequency fp, in which a precise position of the torsion natural frequency fP is determined with a frequency resolution that is at least twice a first frequency resolution of the rough position of the torsion natural frequency fp; determining at least one shift of the torsion natural frequency ΔfP from at least one actually determined torsion natural frequency and from the at least one learnt torsion natural frequency; and combining rolling circumference differences (ΔDIAG, ΔSIDE, ΔAXLE) with the at least one shift of the torsion natural frequency Δfp in a joint warning strategy for detecting and warning of tire inflation pressure loss.