Exhaust control valve system for parallel multi-cylinder two-cycle engine.

摘要

An exhaust control valve arrangement for an in-line, two-cycle, crankcase compression engine (11) which permits the porting (33) arrangement to be rotated relative to the cylinder bore axis (A,B,C) to achieve a compact configuration and wherein all of the exhaust control valves (39) are operated by a single shaft (43) assembly that extends parallel to a plane (D) containing the cylinder bore axes. As a result of this orientation, the exhaust control valves provide an asymmetric exhaust port opening under at least some operative positions of the valves when the valves are in a flow obstructing position. A number of embodiments are disclosed which configure the exhaust control valves so that the port is symmetric in at least some operative obstructing positions of the valves. Also, several embodiments using curved valve configurations are disclosed.