US Patent 7228826 Internal combustion engine valve seating velocity control

The present disclosure provides an engine having a gas exchange valve and an actuator for the gas exchange valve, and also a method of reducing valve seating impact velocity. The actuator includes a body having a fluid inlet and a fluid outlet. A plunger is reciprocable in the body and has a travel distance between an advanced position and a retracted position, the plunger and body defining a chamber. A flow restriction orifice is disposed in at least one of the plunger and the body, and the chamber is in unrestricted fluid communication with the outlet over a first portion of the travel distance and in restricted fluid communication with the outlet by way of the orifice over at least a second portion of the travel distance.