Abstract: An exhaust system having an exhaust manifold that comprises a plurality of single-shell discrete exhaust pipes connected to an engine, a double-shell collective chambered pipe joined to the discrete exhaust pipes and comprising an internal pipe shell into which exhaust gas streams passing through the discrete exhaust pipes are introduced and merge together and an external pipe shell surrounding the internal pipe shell, and a spherical joint connecting the collective chambered pipe to the exhaust pipe. The discrete exhaust pipe has a bent portion and a straight portion continuously extending from the bent portion to the collective chambered pipe. The bent portions of the respective discrete exhaust pipes are oriented toward a center of a straight row of cylinders so as to lay the straight portions of the discrete exhaust pipes nearly parallel to one another.

Abstract: An exhaust system having an exhaust manifold that comprises a plurality of single-shell discrete exhaust pipes connected to an engine, a double-shell collective chambered pipe joined to the discrete exhaust pipes and comprising an internal pipe shell into which exhaust gas streams passing through the discrete exhaust pipes are introduced and merge together and an external pipe shell surrounding the internal pipe shell, and a spherical joint connecting the collective chambered pipe to the exhaust pipe. The discrete exhaust pipe has a bent portion and a straight portion continuously extending from the bent portion to the collective chambered pipe. The bent portions of the respective discrete exhaust pipes are oriented toward a center of a straight row of cylinders so as to lay the straight portions of the discrete exhaust pipes nearly parallel to one another.

Abstract: A cylinder head has a ceramic precombustion chamber for an internal combustion engine. The cylinder head includes a part of the cylinder head made of a ceramic body having an injection aperture communicating with a main combustion chamber for jetting burning gases therethrough, a metal sleeve fitted on an outer circumference of the ceramic body and fitted in a precombustion chamber insert bore forming part of the cylinder head, and a head gasket interposed between the cylinder block forming the main combustion chamber and the ceramic body, the metal sleeve and the cylinder head. A surface of the ceramic body facing to the head gasket extends onto a side of the main combustion chamber beyond a surface of the ceramic body opening the injection aperture into the main combustion chamber.

Abstract: A ceramic precombustion chamber for an internal combustion engine such as a diesel engine consists of a metal ring and a ceramic body fitted in the metal ring by shrinkage fit. The ceramic body has a through-aperture for an injection nozzle and a combustion gas injection aperture. A shrinking allowance at a lower portion of the ceramic body with the metal ring is smaller than that an upper portion of the ceramic body with the metal ring, thereby decreasing surface pressures at the lower portion of the ceramic body to prevent cracks which would occur in the lower portion caused by surface pressures resulting from the shrinkage fit.

Abstract: A ceramic precombustion chamber construction of an internal combustion engine includes at least one ceramic body having a circular cross-section, a metal ring in which the ceramic body is fixed by shrinkage fitting, and at least one key interposed between the ceramic body and the metal ring for preventing rotation therebetween. Contour lines of a key receiving notch formed in an inner circumference of the metal ring are positioned on inner sides of contour lines of a key receiving notch formed in an outer circumference of the ceramic body. With the arrangement, the ceramic body is prevented from loosening from the fitting with the metal ring due to heat and vibration in use and is prevented from being damaged resulting from cracks occurring in the ceramic body.

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: 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 cylinder head to be mounted on a cylinder block for a multiple-cylinder in-line engine has an intake port and an exhaust port for each cylinder bore of the cylinder block, water jackets surrounding the intake ports and the exhaust ports, and a plurality of bolt holes for receiving head bolts for fixing the cylinder head to the cylinder block. The bolt holes are in the form of through-holes formed through boss portions which are disposed in the four corners and on a pair of opposed side portions of the cylinder head. The boss portions on the side portions are in positions corresponding to the "interbore" portions between adjacent cylinder bores of the cylinder block. The upper portions of each pair of boss portions laterally opposed to each other along the corresponding interbore portion are connected by a top deck extending above the interbore portion.