A method of processing information in a tire pressure monitoring system
includes the steps of: establishing a reference temperature; determining a
pressure warning threshold at the reference temperature; measuring gauge
pressure and gauge temperature within a tire cavity; correcting the gauge
pressure to a filtered pressure value at the reference temperature using
the Ideal Gas Law; and comparing the filtered pressure value against the
pressure warning threshold to determine the necessity for a warning
signal. In an advanced form of the invention, the method includes
determining a pressure leak rate; predicting the time interval that the
filtered pressure value will cross the pressure warning threshold at the
leak rate and generating progressive warnings to the driver over the time
interval. Fuzzy logic is used to quantify the probability of a warning
state for each data point, allow for measurement error; and report the
state of maximum probability to minimize the occurrence of false warning.
A warning utility function is derived based upon a combination of the
filtered pressure and leak rate.
