| 摘要 |
PURPOSE:To increase the combustion efficiency by a structure wherein a porous metal- sprayed layer is formed over the wall surface of a cylinder head or a piston crown, by both of which a squash area is formed, in such a manner that the clearance of squash area increases toward the combustion chamber side in tapered form. CONSTITUTION:A cavity 4a, which is made by depressing in a form of nearly elliptic cylinder, is clearly formed on the wall surface of the cylinder head 4 and the combustion chamber 6 is formed by the cavity 4a and the crown of the piston 3 at its top dead center, which also forms together with the wall surface of the cylinder head 2 the squash area with a small clearance therebetween. In such a structure as mentioned above, a metal-sprayed layer 12 is formed on the crown of the piston 3 at the part, which forms the squash area 7 together with the wall surface of the cylinder head 2. The metal-sprayed layer 12 is so inclinedly formed that the clearance of the suqash area is smaller at its outer peripheral part and increases in tapered form with the approach toward the combustion chamber 6. In addition, the metal-sprayed layer 12 is composed of heat resisting synthetic resin 12b such as aromatic cyclic polyester resin or the like containing soft metal 12a such as aluminium, copper or the like and yet provided with suitable voids 12c therewithin. |
