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1. In an internal combustion engine comprising:
an engine block defiling a plurality of cylindrical combustion chambers each defining a chamber axis, a crankshaft mounted to the engine block for rotation about a crankshaft axis extending transversely to the combustion chambers, a piston disposed within each combustion chamber for reciprocation along the chamber axis thereof, the internal combustion engine being operable according to a four stroke cycle wherein the piston reciprocates within the combustion chamber through an intake stroke moving in a first direction, a compression stroke moving in a second direction, an expansion stroke moving in the first direction, and an exhaust stroke moving in the second direction, wherein the position of the piston at the conclusion of the compression stroke and at the beginning of the expansion stroke is defined as top dead center and the position of the piston at the end of the expansion stroke and at the beginning of the exhaust stroke is defined as bottom dead center, a connecting rod pivotably mounted to each piston, a mechanical assembly connecting each connecting rod rotatably to the crankshaft for translating the reciprocating motion of the piston into rotational motion of the crankshaft, the mechanical assembly comprising:
a first gear member non-rotatably mounted to the engine block, the first gear member including:
a cylindrical body with a pinion gear portion having gear teeth formed about a radially outward surface of the cylindrical body, anda second gear member meshingly engaged with the first gear member, the second gear member including:
an annular body with a crown gear portion having gear teeth formed about a radially inward surface of the annular body, the cylindrical body of the first gear member extending into the annular body with the gear teeth of the pinion gear portion in meshing engagement with the gear teeth of the crown gear portion, anda bearing portion projecting outwardly from the crown gear portion and having a first bearing surface formed on an outer surface of the bearing portion and a second bearing surface formed on an inner surface of the bearing portion, the connecting rod being mounted about the first bearing surface and the crankshaft being mounted within the second bearing surface, for rotation of the second gear member with the crankshaft, with the connecting rod rotating on the first bearing surface and the second bearing surface rotating on the crankshaft, the pinion gear portion of the first gear member and the crown gear portion of the second gear member having a gear ratio of 2:1 for causing the second gear member to rotate once for every two rotations of the crankshaft,
the second bearing surface being offset from the crankshaft axis to move in a circular path about the crankshaft axis for imposing a mechanical crank arm on the crankshaft which is uniform throughout the four stroke cycle of the engine,the first and second bearing surfaces being spaced from one another by an offset distance causing the first bearing surface to move alternatingly in inner and outer elliptical paths about the crankshaft for imposing a mechanical cam arm on the crankshaft which varies over the four stroke cycle of the engine,the rotation of the second gear member with the crankshaft imposing a combined effective crank arm on the crankshaft equivalent to the vectorial sum of the crank arm and the cam arm which constantly varies over the four stroke cycle of the engine causing the length of the reciprocation of the piston to vary throughout the four stroke cycle of the engine, the improvement wherein: the first and second bearing surfaces of the second gear member are selectively configured and dimensioned such that:
the cam arm is of a length greater than 20% and up to 100% of the length of the crank arm,at top dead center, the cam arm is oriented at generally substantially 90 degrees to the crank arm,at top dead center, the crank arm is oriented at an angle in advance of the chamber axis,the crank arm and the cam arm act to cooperatively produce a positive torque on the crankshaft beginning before the end of the compression stroke up to about twenty) (20°) in advance of, and continuing through, the top dead center position of the piston into and during the expansion stroke,at the completion of the expansion stroke, each of the crank arm and the cam arm extend in linear alignment with the chamber axis with the cam arm extending outwardly from the crank arm, thereby forming the longest combined effective crank arm during the four stroke cycle of the engine,at the completion of the intake stroke, each of the crank arm and the cam arm extend in linear alignment with the chamber axis with the camp arm extending inwardly in overlapping relation to the crank arm, thereby forming the shortest effective crank arm during the four stroke cycle of the engine,the intake and compression strokes in the four stroke cycle of the internal combustion engine are shorter than the expansion and exhaust strokes, anda substantially uniform compression ratio is maintained throughout the four stroke cycle of the internal combustion engine. |
