Abstract: Herein disclosed is a structure of a divided combustion chamber or a pre-combustion chamber of a Diesel engine of the type, in which the divided combustion chamber is composed of an upper ceramic member having a substantially hemispherical head and a lower ceramic member having an injection port. Either one or both of the upper and lower ceramic members is/are formed with longitudinally and/or transversely extending cut or cuts, slit or slits, and/or groove or grooves at least a portion of the outer surface or surfaces of one or two of those ceramic members. Thus, the resistance of the ceramic members to any rupture is improved so that the divided combustion chamber made of ceramic has highly improved durability.

Abstract: A camshaft having a plurality of cams disposed on a metal shaft in spaced-apart relation with each other in an axial direction of the shaft, comprising at least one ceramic cam portion which is made of a ceramic material, and which includes at least one of the cams. Each of the at least one ceramic cam portion has a pair of joining protrusions which extend from opposite ends thereof in the axial direction of the metal shaft. The camshaft further comprises metallic shaft portions having joining holes which engage the joining protrusions of the ceramic cam portion such that the ceramic cam portion is joined integrally to the metallic shaft portions.

Abstract: A precombustion chamber construction of an internal combustion engine includes an upper ceramic body, a lower ceramic body abutting against the upper ceramic body to form a precombustion chamber communicating through an injection hole with a main combustion chamber of the internal combustion engine, and a metal ring member fitted on outer circumferences of the upper and lower ceramic bodies. According to the invention, the precombustion chamber construction comprises a first key member provided in the upper ceramic body and the metal ring member in the proximity of its upper end, and a second key member provided in the lower ceramic body and the metal ring member in the proximity of its lower end. In this manner, the upper and lower ceramic bodies are prevented from being rotatively moved even if they are subjected to rotating forces caused by vibrations of the engine or explosions of a fuel.

Abstract: Herein disclosed is a structure of a divided combustion chamber or a pre-combustion chamber of a Diesel engine of the type, in which the divided combustion chamber is composed of an upper ceramic member having a substantially hemispherical head and a lower ceramic member having an injection port. Either one or both of the upper and lower ceramic members is/are formed with longitudinally and/or transversely extending cut or cuts, slit or slits, and/or groove or grooves at least a portion of the outer surface or surfaces of one or two of those ceramic members. Thus, the resistance of the ceramics members to any rupture is improved so that the divided combustion chamber made of ceramic has highly improved durability.

Abstract: A ceramic honeycomb filter consisting of a porous ceramic honeycomb structural body having a large number of channels extending therethrough, wherein given channels at one of the opening end surfaces of the honeycomb structural body have sealing portions formed by bending and bonding thin partition walls forming the opening end portion of the channels, and the remaining channels have sealing portions formed by bending and bonding thin partition walls forming another opening end portion of the channels, can be produced in a simple manner and is excellent in durability and mass-productivity.

Abstract: An insulator with a tin oxide semiconductor glaze coating has a portion at least 100.mu. thick extending from the glaze surface in which the ratio of the maximum to the minimum volume resistivity is not more than 30. It is found that such glazes display marked improvement in resistance to deterioration under unfavorable conditions.

Abstract: The invention relates to an electrical insulator coated with a semi-conducting tin oxide system glaze layer wherein the glaze layer contains 0.05 to 10 percent by weight of at least one metal oxide selected from the group consisting of niobium oxide, tantalum oxide, titanium oxide, zirconium oxide, yttrium oxide and tungsten oxide. The additional metal oxide reduces the dependance of resistance on the environmental temperature.