Continuously variable valve lift system with default mechanism

摘要

A continuously variable valve lift system for actuating a combustion valve of an engine includes a camshaft having a camshaft lobe rotatable about an camshaft axis of rotation. A rocker assembly is pivotable for providing reciprocating motion to the combustion valve. A control shaft is rotatable about a control shaft axis of rotation such that rotation of the control shaft about the control shaft axis of rotation changes the position of the rocker assembly to vary the lift of the combustion valve. An actuator selectively rotates the control shaft between a minimum lift position and a maximum lift position. A bias spring surrounding the control shaft axis of rotation biases the control shaft only from the minimum lift position to a predetermined position which is intermediate the minimum lift position and the maximum lift position upon failure of the actuator.