Abstract

A method of controlling resonances in timing drive systems for internal combustion engines having variable cam timing systems using cam phasers with the capability of being locked in position. Locking or unlocking the phaser changes the resonant characteristics of the timing drive system. The invention uses these changes in characteristics between locked and unlocked phasers to minimize the effects of resonance in timing drives by changing between locked and unlocked states as engine RPM passes through resonant points.