Abstract: A valve train for an internal combustion engine including a plurality of cylinders having different valve mechanism constructions, in which the valve train has a correcting member for correcting a difference in valve lift amount that is produced between the plurality of cylinders due to a difference in construction between valve mechanisms so as to make valve lift amounts of the plurality of cylinders substantially uniform.

Abstract: A valve train for an internal combustion engine including a plurality of cylinders having different valve mechanism constructions, characterized in that the valve train has correcting member for correcting a difference in valve lift amount that is produced between the plurality of cylinders due to a difference in construction between valve mechanisms so as to make valve lift amounts of the plurality of cylinders substantially uniform.

Abstract: In a multi cylinder internal combustion engine comprising a cylinder head internally defining exhaust passages and a converging area into which the exhaust passages converge, an upper water jacket and a lower water jacket are formed above and below the exhaust passages, and the lower water jacket has a greater volume than the upper water jacket. Thus, the cooling efficiency for the converging area can be improved by increasing the volume of the part of the water jacket adjacent to the converging area. Also, because the upper water jacket has a relatively small volume, the load on the core parts supporting the core part for defining the upper water jacket can be reduced, and the overall mechanical strength of the core can be improved. By extending the water jackets to the converging area, the cooling efficiency can be improved even further.

Abstract: In an internal combustion engine including bearing sections rotatably carrying a camshaft and provided integrally or separately on a cylinder head, and rocker arms moved with the rotation of the camshaft and swingably carried on rocker shafts, a rocker shaft holder fastened and fixed to the bearing sections to support the rocker shafts is provided with accommodating recesses into each of which a portion of each of the bearing sections protrudes. Thus, the support rigidity of the rocker shafts can be enhanced and moreover, an increase in size of the engine can be avoided.

Abstract: In an internal combustion engine including a rocker shaft holder which comprises a plurality of shaft-supporting sections connected together and disposed at distances in a direction of arrangement of cylinders and which is fixed to a cylinder head, and rocker shafts each of which swingably carries thereon a plurality of rocker arms and which are supported by the shaft-supporting sections, an oil sump is defined in an upper surface of the rocker shaft holder, and lubricating oil passages are provided in the rocker shaft holder to communicate with the oil sump, so that a lubricating oil can be supplied to slide portions of at least some of the rocker arms. Thus, an increase in number of parts can be avoided in the lubrication of the slide portions of at least some rocker arms.

Abstract: A vehicle multi-cylinder engine in which a plurality of banks each comprising a cylinder row portion and a cylinder head and set at an angle relative to each other are disposed so as to be offset from each other in an axial direction of a crankshaft, and in which valve operating characteristics changing mechanisms for changing the operating characteristics of engine valves in response to oil pressure control by an oil pressure control valve are incorporated in the valve trains on the cylinder head of at least either of the respective banks. An oil pressure control valve is disposed in a space produced between end portions of adjacent banks at one ends thereof along an axial direction of a crankshaft as the respective banks are offset from each other and is attached to at least one cylinder head.

Abstract: An engine air-oil separator provided in a head cover for separating oil contents in blow-by gases that are recirculated to an intake system, wherein a centrifugal separation chamber for generating swirl flows in the blow-by gases is formed integrally with the head cover by a rib-like wall protruding inwardly from an internal surface of an external wall of the head cover, whereby since the centrifugal separation chamber can be embedded in the head cover, the space saving can be attained.

Abstract: In a multi cylinder internal combustion engine comprising a cylinder head internally defining exhaust passages extending from a plurality of combustion chambers defined in part by the cylinder head, the exhaust passages converging into a converging area also internally defined in the cylinder head, an oxygen sensor for detecting an oxygen concentration in exhaust gas is passed into the converging area substantially in parallel with a cylinder axial line. Thus, the oxygen sensor can be mounted relatively close to the combustion chamber while permitting the sensor to be uniformly exposed to the exhaust gas from the combustion chambers of an entire cylinder bank. Therefore, the oxygen sensor can be activated relatively quickly substantially without any warm-up, and can measure the oxygen concentration of the overall exhaust gas.

Abstract: An engine air-oil separator provided in a head cover for separating oil contents in blow-by gases that are recirculated to an intake system, wherein a centrifugal separation chamber for generating swirl flows in the blow-by gases is formed integrally with the head cover by a rib-like wall protruding inwardly from an internal surface of an external wall of the head cover, whereby since the centrifugal separation chamber can be embedded in the head cover, the space saving can be attained.

Abstract: A vehicle multi-cylinder engine in which a plurality of banks each comprising a cylinder row portion and a cylinder head and set at an angle relative to each other are disposed so as to be offset from each other in an axial direction of a crankshaft, and in which valve operating characteristics changing mechanisms for changing the operating characteristics of engine valves in response to oil pressure control by an oil pressure control valve are incorporated in the valve trains on the cylinder head of at least either of the respective banks. An oil pressure control valve is disposed in a space produced between end portions of adjacent banks at one ends thereof along an axial direction of a crankshaft as the respective banks are offset from each other and is attached to at least one cylinder head.

Abstract: In an internal combustion engine including a rocker shaft holder which comprises a plurality of shaft-supporting sections connected together and disposed at distances in a direction of arrangement of cylinders and which is fixed to a cylinder head, and rocker shafts each of which swingably carries thereon a plurality of rocker arms and which are supported by the shaft-supporting sections, an oil sump is defined in an upper surface of the rocker shaft holder, and lubricating oil passages are provided in the rocker shaft holder to communicate with the oil sump, so that a lubricating oil can be supplied to slide portions of at least some of the rocker arms. Thus, an increase in number of parts can be avoided in the lubrication of the slide portions of at least some rocker arms.

Abstract: In an internal combustion engine including bearing sections rotatably carrying a camshaft and provided integrally or separately on a cylinder head, and rocker arms moved with the rotation of the camshaft and swingably carried on rocker shafts, a rocker shaft holder fastened and fixed to the bearing sections to support the rocker shafts is provided with accommodating recesses into each of which a portion of each of the bearing sections protrudes. Thus, the support rigidity of the rocker shafts can be enhanced and moreover, an increase in size of the engine can be avoided.

Abstract: In a multi cylinder internal combustion engine comprising a cylinder head internally defining exhaust passages and a converging area into which the exhaust passages converge, an upper water jacket and a lower water jacket are formed above and below the exhaust passages, and the lower water jacket has a greater volume than the upper water jacket. Thus, the cooling efficiency for the converging area can be improved by increasing the volume of the part of the water jacket adjacent to the converging area. Also, because the upper water jacket has a relatively small volume, the load on the core parts supporting the core part for defining the upper water jacket can be reduced, and the overall mechanical strength of the core can be improved. By extending the water jackets to the converging area, the cooling efficiency can be improved even further.

Abstract: In a multi cylinder internal combustion engine comprising a cylinder head internally defining exhaust passages extending from a plurality of combustion chambers defined in part by the cylinder head, the exhaust passages converging into a converging area also internally defined in the cylinder head, an oxygen sensor for detecting an oxygen concentration in exhaust gas is passed into the converging area substantially in parallel with a cylinder axial line. Thus, the oxygen sensor can be mounted relatively close to the combustion chamber while permitting the sensor to be uniformly exposed to the exhaust gas from the combustion chambers of an entire cylinder bank. Therefore, the oxygen sensor can be activated relatively quickly substantially without any warm-up, and can measure the oxygen concentration of the overall exhaust gas.