| 摘要 |
A four-valve cylinder head of a four-stroke engine has a body formed with an enlarged material cross-section portion located above a combustion chamber to increase heat exchange surface in the cylinder head. For cooling the cylinder head the latter is further formed with a straight passage receiving cooling air therethrough. The passage includes a central portion, a funnel-shaped portion communicating with the central portion, and a conical suction portion also communicating with the central portion. Cooling air is introduced into the interior of the head through the funnel-shaped portion and is sucked away through the conical suction portion. |
