| 摘要 |
<p>PURPOSE:To achieve a lower emission to avoid the decrease in the engine output, by forming part of the wall surface of a suction manifold M as an open port, making changeable the shape of a closure lid closing this open port, and thereby making variable the volume of the suction manifold. CONSTITUTION:The engine has a first air cylinder C1 and a second air cylinder C2 which have a phase difference of 180 deg. in terms of crank angle. A suction manifold M is not only shaped like a cylinder but is also provided, at its top, with a large open port. If the open port 9 is left open as it stands, a fuel-air mixture would escape. Therefore, this opening is selectively closed by a closure lid 3 or 23. By making the volume of the suction manifold M small, the suction efficiency is increased to prevent decrease in the engine output. Conversely, by making positively large the volume of the suction manifold M, the reduction in emission is improved.</p> |
