HEAT-INSULATING MEMBER FOR SUBSIDIARY COMBUSTION CHAMBER OF INTERNAL-COMBUSTION ENGINE

摘要

PURPOSE:To improve the mechanical strength, heat insulation, heat resistance and durability of a subsidiary combustion chamber of an internal combustion engine, by fixing a disk-like member having a nozzle and made of sintered silicon nitride to the open end of a bell-shaped hollow member. CONSTITUTION:A metal having a coefficient of thermal expansion greater than that of a sintered material of partially stabilized zirconia and smaller than 17X 10-6/ deg.C always in the temperature range of normal temperatures to 700 deg.C is formed, by way of casting, over the outer surface of a bell-shaped hollow member 2 made of the sintered material of partially stabilized zirconia. Further, a disk-like member 6 having a nozzle 5 and made of sintered silicon nitride is fixed to the open end 4 of the hollow member 2. In fixing the disk-like member 6 to the open end 4 of the member 2, for instance, zircon sand containing water-glass is at first charged into the inside 8 of the hollow member 2 and the nozzle 5 of the member 6 and after the hollow member 2 and the disk-like member 6 are fixed together with hardening of water-glass, they are convered with the metal 3 simultaneously by way of casting. Thus, since the disk-like member 6 made of sintered silicon nitride excellent in heat-insulating properties is fixed to the open end 4, it is enabled to prevent fusion loss at the portion.