Patent ID: 7942657

Claim:
A four-cycle internal combustion engine, comprising: a case having at least two internal chambers, each chamber formed by at least one non-circular, constant-diameter circumscribing wall; a single rotatable shaft extending through the at least two internal chambers and through the case in two opposing directions and rotatable about an axis of rotation that is coincident with a longitudinal axis of the shaft; a first single rotor slidably mounted on the exterior of the shaft for translational movement to slide along an axis that is substantially perpendicular to the axis of rotation of the shaft as the rotor rotates within the chamber; and a second single rotor of the same size as the first rotor and slidably mounted on the exterior of the shaft for translational movement along an axis substantially perpendicular to the axis of rotation of the shaft and at 180 degrees to the axis of translational movement of the first single rotor and at least one second chamber oriented at 180 degrees to the at least one first chamber with respect to the axis of rotation of the shaft; each rotor comprising a contour surface shaped to give a first segment of the rotor a larger surface area than a surface area of a corresponding second segment of the rotor to allow more force to act on the first segment of the rotor than on the second segment of the rotor during an expansion phase of an operating cycle of the system, the first segment of the rotor comprising a portion of the rotor from a lateral axis of the rotor to a first end, and the second segment of the rotor comprising a portion of the rotor on an opposite side of the lateral axis and extending from the lateral axis to a second end of the rotor.