| 摘要 |
PURPOSE:To facilitate sintering work of ceramic further increase its strength while obtain heat insulation at an outlet side easily further at low cost, by both forming a ceramic layer to an internal peripheral face at an inlet side of an exhaust port and mounting a port liner to the outlet side. CONSTITUTION:An exhaust port 20 communicated to a combustion chamber of a cylinder is formed to a cylinder head 17. Here a ceramic layer 23 is formed to an inlet side in the internal peripheral surface of the port 20 where an exhaust valve 19 is provided. While a port liner 24 consisting of, for instance, stainless steel is mounted to an outlet side of the port 20. In this way, only a part in the inlet side of the port 20 is heat insulated by the layer 23 to easily sinter ceramic further increase its strength. Further the existence of the liner 24 can facilitate a countermeasure of heat insulation in the outlet side of the port 20 easily further at low cost. |
