| 摘要 |
PURPOSE:To provide a compact and light exhaust manifold, simplify and facilitate the removably attaching operation of an ignition source by arranging the ignition sources for the 2 outermost side cylinders near the outside of a cylinder head such that exhaust valves for the 2 inside cylinders approach each other. CONSTITUTION:Exhaust valve ports 121-124 in the respective roof surfaces of combustion chambers 61-64 are offsetted to one side and opened opposed to one intake valve port 8b. On the other side of each roof surface are arranged respectively plug mounting holes 151-154 parallel to exhaust valves 141-144. The holes 151-154 are also opened to be opposed to each one intake valve 11a. Ignition plugs P1, P4 corresponding to the 2 outside cylinders are arranged near the outside of a cylinder head 2 and ignition plugs P2, P3 corresponding to 2 cylinders near the inside are arranged near the outside. The whole longitudinal width of an exhaust manifold is shortened and a relatively wide space is formed around the ignition plugs P1-P4 so that the ignition plugs can be easily attached and removed. |
