Patent ID: 6766776
Filing Date: 2004-07-27
Classification: F01L,F02D

Abstract:
A method of controlling a variable cam timing system comprising a phaser having a range of travel between a plurality of physical stops defining limits of rotational travel, wherein when the phaser is rotated to one of the physical stops, the phaser is at an extreme of its range of travel, such that the phaser can no longer move any further in one direction, comprising the steps of:a) providing a set of tooth pulses from camshaft and crankshaft position sensors; b) filtering said set of tooth pulses; c) analyzing the filtered tooth pulses to determine whether the phaser is moving or not moving; d) determining that the phaser is rotated to one of the physical stops when the phaser is not moving and an output of a phaser controller is commanding the phaser to move; and e) storing a position representative of at least one physical stop of said phaser.