A reciprocating two-stroke uniflow internal combustion (IC) cylinder and multiple cylinder engine, the cylinder having a cylinder wall and a cylinder head, the cylinder head having an exhaust port, a fuel injector, and a spark means disposed through the cylinder head, a piston reciprocally mounted in the cylinder for movement alternately through compression and power strokes, and a scroll plenum extending unidirectional around the outside of the cylinder wall and having an inlet and a plurality of swirl ports disposed through the cylinder wall providing fluid communication from the scroll plenum into the cylinder chamber, wherein the plurality of swirl ports enter the cylinder chamber tangentially with respect to the axial centerline of the cylinder, and wherein the plurality of swirl ports are subject to opening and closing in response to movement of said piston.