| 摘要 |
PURPOSE:To prevent a rotary valve from overheating, by transmitting rapidly heat in a high temperature portion to a low temperature portion through an action of a heat pipe. CONSTITUTION:A rotary valve 7 is fitted rotatably and slidably in a static sleeve 6 fixed to a cylinder head 5, while a cooling fin 14 is fixed to an end 17 of its shaft. And a hollow 19 is formed within a valve portion 21 of a rotary valve 7 and its shaft portion so as to form a taper inner face 20, while water in proper quantity is charged. And a heat pipe is composed of the whole shaft portion of the rotary valve 7 and its valve portion 21. In the valve portion 21 being elevated highly in temperature with heat of exhaust gas, water is vaporized to be moved to the end 17 of the shaft of a low temperature and is cooled by a cooling fan so as to be liquefied to adhere to an inner wall. The water is rapidly moved to the valve portion 21 along the taper inner face 20, and thereby a low temperaure may be maintained. |
