Exhaust control device for a two-cycle engine.

摘要

Object: To provide an exhaust control device for a two-cycle engine which does not impart a change of a shape of an exhaust passage. Constitution: An exhaust control device 15 provided in an exhaust port 7 opening to an inner peripheral surface of a cylinder hole 5 of a two-cycle engine 1, wherein a cylinder wall portion 17 adjacent to the exhaust port 7 is formed with a rotational face 21 obtained by rotating an arc having substantially the same curvature as the inner peripheral surface of the cylinder hole 5 about a rotational axis C1 extending at a right angle to an axis C of said cylinder hole in the outside of said cylinder hole and a recess 16 defined by both ends at a right angle to the rotational axis C1 and in communication with the.exhaust port 7; within said recess is mounted an exhaust passage member 18 having an exhaust passage 27 in communication with the exhaust port 7 and having an external shape substantially similar to said recess with a predetermined clearance formed relative to said recess in a portion above at least an upper edge 7a of the exhaust port 7 of said rotational face portion 21 and said both end portions; and a valve body 20 is provided which comprises arm portions 34 respectively inserted into the clearance in said both end portions and supported for swinging about the rotational axis C1 and a control face portion 35 provided by connecting ends of said arm portions together and movable in and out of the clearance 28 in the rotational face portion 21 in response to the swinging of the arm portions 34. <IMAGE>