Exhaust valve throttling mechanism for two-stroke engine

Abstract

An improved exhaust port throttling mechanism for a two-stroke engine. The engine includes a plurality of in-line cylinders each having an exhaust passage disposed to be closed during reciprocating movement of the piston. The exhaust passages communicate with a common exhaust chamber and a tubular valve member is mounted for rotation within the exhaust chamber. The valve member includes a plurality of apertures, each adapted to register with one of the exhaust passages. When used with a V-6 engine having two banks of in-line cylinders, a shaft is connected to each valve member and the corresponding ends of the shafts are interconnected by meshing gear segments. One of the gear segments is connected through a linkage to the throttle lever for the engine so that the valve members will be rotated by actuation of the throttle lever between a substantially closed position at low speeds, where the valve members substantially close off the exhaust passages, to an open position at high speeds where the apertures in the valve members are in full registry with the exhaust passages, so that the exhaust gas is discharged via the interior of the valve members without restriction.