Patent ID: 9334789
Filing Date: 2016-05-10
CPC Classification: F02B,F02M

Claim Text:
1. A gas transfer port system for a cylinder of a two-stroke internal combustion engine; said cylinder provided with a fixed separator plate dividing said cylinder into an upper cylinder and a lower cylinder; a piston in said cylinder reciprocating between said separator plate and a cylinder head; and wherein an annular skirt descending from said separator plate forms at least a portion of an annular well between said skirt and an internal surface of said cylinder; said annular well sealed at the bottom such that said upper cylinder is isolated from a crankcase of said engine; said gas transfer port system including at least one short gas transfer port; said short gas transfer port having an inlet aperture at an internal surface of a wall of said cylinder proximate said underside of said piston when at Bottom Dead Centre (BDC); an inlet charge gas under a descending said piston flowing through said short gas transfer port to a gas transfer port outlet aperture in a wall of said cylinder; said gas transfer port outlet aperture located above an upper surface of said piston when at bottom dead centre (BDC); said annular well in communication with said gas transfer port outlet aperture in said wall of said cylinder; said short gas transfer port relieving a rapid rise in pressure causing an accelerated pulse of said inlet charge gas from between an upper surface of said separator plate and an underside of said piston approaching BDC; said pulse of inlet charge gas from said short gas transfer port assisting the scavenging of said inlet charge gas from said annular well for exit through said gas transfer port outlet aperture into said upper cylinder; said annular well forming a long transfer port leading towards said gas transfer port outlet aperture.