Variable valve timing control apparatus for an internal combustion engine

摘要

A cam has a profile variable from a high lift curve to a low lift curve in an axial direction. A driving mechanism shifts a cam shaft in the axial direction. A phase adjusting mechanism adjusts the rotational phase of the cam shaft relative to a driving shaft of the internal combustion engine. Angle detecting teeth are shift detecting teeth are alternately arranged on a same cylindrical surface of the cam shaft. Each shift detecting tooth incline at a predetermined angle with respect to an axis of the cam shaft so as to provide angularly advanced and retarded portions in a rotational direction of the cam shaft. A pickup generates sensing signals responsive to the angle detecting teeth and the shift detecting teeth. The sensor faces the angularly advanced portion of the shift detecting tooth when the low lift curve of the cam is selected and faces the angularly retarded portion of the shift detecting tooth when the high lift curve of the cam is selected.