An internal combustion engine to reduce abrasion with a piston while retaining oil film on an upper portion of a cylinder includes: a cylinder block that includes a cylinder, and a piston that is stored in the cylinder in a manner capable of reciprocating along an axis line of the cylinder, in which the cylinder includes a multi-bulging inner circumference portion in which a diameter in a thrust-anti thrust direction is a minimal diameter.

An internal combustion engine to reduce abrasion with a piston while retaining oil film on an upper portion of a cylinder includes: a cylinder block that includes a cylinder, and a piston that is stored in the cylinder in a manner capable of reciprocating along an axis line of the cylinder, in which the cylinder includes a multi-bulging inner circumference portion in which a diameter in a thrust-anti thrust direction is a minimal diameter.

A structural frame is provided. The structural frame includes a bottom surface, first and second cylinder block sidewall engaging surfaces, the first and second cylinder block sidewall engaging surfaces positioned above the bottom surface at a height that is above a centerline of a crankshaft support included in a cylinder block when the structural frame is coupled to the cylinder block.

An engine has a cylinder block formed by a block material and defining at least one cylinder. The block defines a lubrication circuit with fluid passages including an inlet passage, a main oil gallery, a crankshaft bearing lubrication passage, and a piston ring lubrication passage. The fluid passages are formed by continuous metal walls in contact with and surrounded by the block material. At least one of the fluid passages is curved. A method of forming a component with an internal pressurized lubrication circuit includes positioning a lost core insert in a tool, with the insert shaped to form a lubrication circuit. The lost core insert has a lost core material generally encapsulated in a continuous metal shell, and at least one curved section. Material is provided into the tool to form a body surrounding the lost core insert thereby forming a component preform.

An engine has a cylinder block formed by a block material and defining at least one cylinder. The block defines a lubrication circuit with fluid passages including an inlet passage, a main oil gallery, a crankshaft bearing lubrication passage, and a piston ring lubrication passage. The fluid passages are formed by continuous metal walls in contact with and surrounded by the block material. At least one of the fluid passages is curved. A method of forming a component with an internal pressurized lubrication circuit includes positioning a lost core insert in a tool, with the insert shaped to form a lubrication circuit. The lost core insert has a lost core material generally encapsulated in a continuous metal shell, and at least one curved section. Material is provided into the tool to form a body surrounding the lost core insert thereby forming a component preform.

A cylinder liner is disclosed for use with an engine. The cylinder liner may have a hollow generally cylindrical body with a top end and a bottom end, and a flange extending radially outward at the top end of the hollow generally cylindrical body. The cylinder liner may also have a seal end stop formed on an outer annular surface of the hollow generally cylindrical body an axial distance away from the flange, and an annular groove formed within the outer annular surface of the hollow generally cylindrical body at a location between the end stop and the bottom end.

Disclosed are an engine having a cylinder block and a method for manufacturing an engine having a cylinder block. The engine may include cylinder liners each having a cylinder space formed therein, a protruded portion formed on an outside circumference thereof, and a flat surface formed on one side of the protruded portion. The cylinder liners may be arranged such that the flat surfaces of adjacent cylinder liners are in close contact with one another. The engine may also include a liner covering unit formed to surround an outside of the cylinder liners, and an outer block which forms a cooling water chamber with an outside surface of the liner covering unit.

A thermally coated component is disclosed. The thermally coated component has a frictionally optimized surface of a track for a friction partner, where the surface has pores. The pores have an entry rounding, the slope of which, as a ratio of the depth of the entry rounding to a longitudinal section of the surface or parallel to the surface, has a value of more than 2.5 m/mm.

A cam bearing lubrication structure for an internal combustion engine includes a cylinder head having a cam bearing region, a plug hole for an ignition plug and a plug tube fitted liquid-tight therein. The cam bearing lubrication structure includes an outer periphery oil path bypassing along an outer peripheral face of the plug tube, a main lubricating oil passage extending through the plug hole and formed to connect to the outer periphery oil path and a guide passage formed in and through the cam bearing region to connect a sliding face of the cam bearing region from the outer periphery oil path and supplying lubricating oil to a sliding face of the cam bearing region and a camshaft. In addition, a lubricating oil supplying structure is provided for a valve apparatus for further increasing the oil supply amount to achieve a further increase in the speed of the engine.

A cam bearing lubrication structure for an internal combustion engine includes a cylinder head having a cam bearing region, a plug hole for an ignition plug and a plug tube fitted liquid-tight therein. The cam bearing lubrication structure includes an outer periphery oil path bypassing along an outer peripheral face of the plug tube, a main lubricating oil passage extending through the plug hole and formed to connect to the outer periphery oil path and a guide passage formed in and through the cam bearing region to connect a sliding face of the cam bearing region from the outer periphery oil path and supplying lubricating oil to a sliding face of the cam bearing region and a camshaft. In addition, a lubricating oil supplying structure is provided for a valve apparatus for further increasing the oil supply amount to achieve a further increase in the speed of the engine.