| 摘要 |
PURPOSE:To secure a high temperature and high strength hot plug by forming this hot plug with Si3N4 ceramics making Si3N4 the main ingredient, and whose uneven surface roughtness is in a special range, in this hot plug having an antechamber and installing a connecting hole interconnecting both main-sub chambers. CONSTITUTION:In an antechamber type engine with a hot plug 8 constituting an antechamber 2 set up in a cavity 11 formed in a cylinder head 3, this hot plug 8 is formed into a two-piece structure consisting of an upper chamber part 5 and a hot plug part 4, and a connecting hole 7 tilting in a tangential direction to the antechamber 2 is installed in this hot plug part 4. In this connection, the hot plug 8 is made of Si3N4 ceramics consisting in Si3N4 as the main ingredient. At this time, grain of the hot plug 8 sintered intact is set to such one as having an uneven surface consisting of the grain boundary phase of columnar Si3N4 and columnar Si3N4, and surface roughness on the uneven surface of this grain is set to the range of Rz=2.5mum to 6.6mum. |
