EXHAUST EMISSION CONTROL DEVICE OF 2-STROKE-CYCLE ENGINE

摘要

PROBLEM TO BE SOLVED: To increase the output characteristics of engine by suppressing the leakage of air-fuel mixture or blow by gas into a minute clearance between the tip face 16a of an exhaust emission control valve and the inner end face of a storage recessed part opposed to the tip face in an exhaust emission control device of a 2-stroke-cycle engine. SOLUTION: In this exhaust emission control device of the 2-stroke cycle engine, the storage recessed part 17 continued with an opening part upper edge 11a to the cylinder bore 3a of a port 11 is provided in an upper part inside wall of the exhaust port 11 in a cylinder block 3, and an exhaust emission control valve 16 swingable between a full open position O stored in the recessed part 17 and a full close position C projected from the storage recessed part 17 to the exhaust port 11 is pivotally supported on the cylinder block 3. A labyrinth groove 27 is formed in at least one of the tip face 16a of the exhaust emission control valve 17 and the inner end face 17a of the storage recessed part 17 opposed to the tip end face 16a.