An Electronically Controlled Cam Phasing System

A system was developed to control the intake valve timing of a twin cam engine. With this scheme the intake cam can be phased to any position within a 33 crank degree range. The phase angle of the cam is continuously updated by an electronic control unit to reflect changes in engine operating conditions. A control strategy was established which would optimize power at large throttle angles and minimize emissions at part throttle as well as provide a smooth idle condition. All of this is possible with no increase in fuel consumption. The system is inexpensive and requires no major engine casting modifications. It packages without adding to overall engine length.