| 摘要 |
In a valve actuation apparatus of an internal combustion engine employing a motion converter for converting a rotary motion of a drive cam into an oscillating motion of a rockable cam, the rockable cam has a cam contour surface, for operating an engine valve by the oscillating motion. The cam contour surface is contoured to have a valve-opening small lift area through which the cam contour surface extends from a base-circle area, a valve-opening middle lift area extending continuously from the valve-opening small lift area toward a cam-nose portion, and a valve-opening large lift area extending continuously from the valve-opening middle lift area toward a cam-nose top. A radius of curvatureρ2 of a part of the valve-opening middle lift area, bordering the valve-opening small lift area, is set to be less than a radius of curvatureρ3 of the valve-opening large lift area. |
