Patent ID: 8534268

Claim:
An engine comprising: a) a hollow crankcase; b) a hollow cylinder opening at one end into the opening of crankcase, the cylinder including: at least one first port for the admission of air; a second port for the admission of a mixture of air and fuel; and a third port for the expulsion of exhaust gases; c) a piston situated within the cylinder, in which: the piston is free to move up and down along an axial dimension of the cylinder; and the piston substantially fills a cross-sectional area of the cylinder so as to substantially divide the volume of the cylinder into a combustion chamber on one side of the piston and a crankcase chamber on the other side of the piston; d) a piston pin that is attached to the piston, in which the long axis of the pin lies substantially perpendicular to the direction of motion of the piston; e) a crankshaft extending through the crank case; f) a crank web attached at its center to the crankshaft; g) a connecting rod, in which one end of the connecting rod is attached to the piston pin and the other end of the connecting rod is attached to a crank pin on the crank web; and h) an ignition source operable to supply ignition to the combustion chamber, in which the engine translates up and down motion of the piston into a circular motion of the crankshaft via the intermediation of connecting rod and crank web; in which the cylinder includes at least one first transfer passage with at least one fourth port opening into the combustion chamber, and at least one fifth port opening into the crankcase chamber; in which the piston includes at least one tunnel defining a completely interior surface throughout the piston with a sixth port opening to one side of the long axis of the piston pin and a seventh port opening to the other side of the long axis of the piston pin, such that at a given position of the piston, the sixth port interfaces to the first port and the seventh port interfaces to the fourth port; and in which the first passageway is substantially perpendicular to the piston pin.