| 摘要 |
PURPOSE:To improve the output of engine in the entire range of high, middle and low rotation by providing, in the manifold of the exhaust pipes, a valve mechanism composed of a first valve body which can expand/shrink the sectional area of a passage by rising from/setting in the exhaust passage of an exhaust pipe and a second valve body which can mutually connect/cut-off respective exhaust passages of the exhaust pipes. CONSTITUTION:Plural exhaust pipes 3 are arranged in a manifold, mutually adjoining up/down and right/left and a valve mechanism 7 is arranged between upper exhaust passages 3a, 3b and lower exhaust passages 3c, 3d in a valve casing 6 arranged in that part. This valve mechanism 7 is composed of a first valve body 8 which can expand/shrink the passage sectional areas of the exhaust passages 3a - 3d and a second valve body 9 which can connect/cut-off the upper exhaust passages 3a, 3b to/form the lower exhaust passages 3c, 3d. For example, in the low rotation range of an engine, respective exhaust passages 3a - 3d are throttled by rotating a cam plate 20 by means of an engaging projection 22 through a rotating shaft 16 and projecting the first valve body 8 in respective exhaust passages 3a - 3d, while the valve hole 13 of the second valve body 9 is blocked by the first valve body 8 and respective exhaust passages 3a - 3d are mutually disconnected. |
