Method and apparatus for predicting life of air filter cartridges

Claim 1

Method of predicting the remaining service life of an air filter element for the combustion air induction system of an internal combustion engine powering a motor vehicle, said filter element having a maximum permitted pressure drop across the filter element representing the maximum service life of said element at which pressure drop said element is no longer usable, means for measuring the pressure drop across said filter element, and means for establishing the usage of said filter element from the initial use of such filter element, comprising the steps of measuring the pressure drop across the filter element at the end of successive usage intervals, memorizing the pressure drop and the usage at the end of each such usage interval, determining from the pressure drop measured at the end of each usage interval and the accumulated usage at the end of each such usage interval the rate at which the pressure drop is increasing, determining from said rate of increase the predicted usage at which said maximum permitted pressure drop will occur, and selectively displaying the usage at which the maximum pressure drop will occur.