Active manifold

An internal combustion engine intake manifold comprising a plenum from which extends at least one transverse runner to at least one combustion chamber of the engine wherein each such runner has a selectable effective length between the plenum and a corresponding combustion chamber provided by a selective opening and closing of a door between the runner and the plenum chamber, said door is disposed on a shaft, said shaft is mounted for rotary motion on said plenum about an axis, characterized in that said door and shaft are carried by an underlying tray disposed against an underlying wall of said plenum containing an entrance to such runner from the plenum, said tray contains a hole overlying said entrance, and said door is selectively operable to pass through said hole to open and close said entrance.

A method of making an internal combustion engine intake manifold comprising a plenum that is laterally bounded by one or more runners from the plenum to one or more combustion chambers of the engine wherein each such runner has a selectable effective length between the plenum and a corresponding combustion chamber provided by the selective opening and closing of a door between the runner and the plenum chamber, said door is disposed on a shaft, said shaft is mounted for rotary motion on said plenum about an axis, said door projects radially of said axis outwardly beyond said shaft, and said shaft passes from said plenum through an opening in an end wall of said plenum, characterized in that said door and shaft are joined together to form a unit, said unit is inserted lengthwise into said plenum through an opening in an end wall of said plenum that is sized and shaped to allow for the passage of said unit therethrough, and said opening is thereafter closed by a closure member through which said shaft passes for connection exteriorly of said plenum to an actuator.