Two-stroke internal combustion engine with variable compression ration and an exhaust port shutter

Abstract

With reference to FIG.A, the present invention provides a two-stroke internal combustion engine comprising: a piston () reciprocable within a cylinder (); an exhaust port () allowing communication of the cylinder () with an exhaust passage (), which port () is opened and closed by the piston during the reciprocal motion thereof; moveable shutter means () for varying the effective area of the exhaust port (), which shutter means () varies the effective area cyclically in a timed relationship to the reciprocal motion of the piston () within the cylinder (); a compression ratio variation mechanism () additional to and separate from the moveable shutter means () for varying a compression ratio of the cylinder (); sensor means () for measuring one or more operating characteristics of the engine and for generating signals corresponding thereto; and a control unit () which processes the signals generated by the sensor means () and controls the motion of the shutter means () accordingly and control the effective area of the exhaust port () and controls the compression ratio variation mechanism () to independently vary the compression ratio of the cylinder ().