Variable valve operating system of internal combustion engine enabling variation of valve-lift characteristic

摘要

In an engine employing a variable lift and working angle control mechanism enabling both a valve lift and a working angle of an intake valve to be continuously simultaneously varied depending on engine operating conditions, the control mechanism includes at least a rocker arm and a control shaft formed integral with an eccentric cam. The valve lift characteristic of the control mechanism varies by changing an angular position of the control shaft. A control-shaft position sensor has a directivity for the sensor output error occurring owing to a change in relative position between the control shaft center and the position sensor. The error becomes a minimum value in a specified direction of relative position change. The specified direction of relative position change is set to be substantially identical to a direction of a line of action of load acting on the center of the control shaft during idling.