A two-stroke, uniflow, full expansion internal combustion (IC) engine having cylinders that include a cylinder wall and a cylinder head having an exhaust port with exhaust valve, a fuel injector, and a spark means in the cylinder head, and a piston mounted in the cylinder for reciprocal stroke movements of compression and power between a top dead center (TDC) position and a bottom dead center (BDC) position. The cylinder has a swirl inlet port passing through the cylinder wall at the bottom of the cylinder that is covered and uncovered in response to the reciprocal movement of the piston. The cylinder is operated through a cycle where the exhaust port is held in an open position for a portion of the compression stroke movement of the piston, to provide a delay in the onset of the compression phase of the cylinder cycle.