Patent ID: 7350487

Claim:
A method for reducing instability of rotational holding position of a rotor in a stator of a camshaft phaser during operation thereof by an associated internal combustion engine, wherein the camshaft phaser includes a plurality of actuating chambers selected from a plurality of timing-advance chambers and timing-retard chambers, the actuating chambers being supplied selectively with oil according to a selected duty cycle for providing a predetermined rotational holding position of the rotor within the stator, and wherein the camshaft phaser includes a target wheel for creating interrupted signals, the amplitudes of which are indicative of the magnitude of the instability, the method comprising the steps of: a) providing a predetermined alarm level for said instability amplitude as indicated by said interrupted signals; b) monitoring said instability amplitude of said interrupted signals; c) activating a default correction function when said instability amplitude exceeds said predetermined alarm level; and d) operating said default correction function to apply a bias to said selected duty cycle in service of said actuating chambers.