Internal combustion engine comprising means for controlling the axial extent of a port in a cylinder

Claim 1

In a two-stroke-cycle internal combustion engine comprising cylinder structure having an inside peripheral surface which defines a cylinder bore and is formed with a port which has an axial extent along the axis of said cylinder bore, said cylinder structure being formed with a flow passage which at one end adjoins said port and has a boundary surface portion which adjoins said port at one end of said axial extent, a piston, which is axially reciprocable in said cylinder bore and adapted to open and close said port, and a pivoted restricting member which defines said flow passage on one side thereof adjacent to said port and has a restricting edge which faces said port and extends generally in the peripheral direction of the adjacent portion of said inside peripheral surface, said restricting member being angularly movable between a full-flow position, in which said restricting edge is clear of said port, and a restricting position, in which said restricting edge extends across said port intermediate said axial extent and is substantially flush with said inside peripheral surface, the improvement residing in that said restricting member constitutes a hinged member, which is formed with said restricting edge at one end and is pivoted at its end that is opposite to said restricting edge.