In a sliding structure for an internal combustion, a cylinder has recesses in a stroke center region. Piston rings have inclined surfaces on an outer circumferential surface, and a lubricating oil flows between the inner wall surface and the outer circumferential surface that relatively move via the inclined surfaces. At any RPM equal to or greater than at idle, a center friction coefficient at the stroke center region through which the piston rings pass at the highest speed is less than a center friction coefficient when no recesses are formed in the stroke center region. Contrarily, at the RPM, an outside friction coefficient when the piston rings pass through a region outside the stroke center region is less than an outside friction coefficient when the recesses are formed in the outside region. As a result, further improved low fuel efficiency is achieved for the dimple liner technique.

Internal combustion engines having a split crankshaft are disclosed. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The pistons also may have a domed piston head with depressions thereon to facilitate the movement of air/charge in the cylinder. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

Internal combustion engines having a split crankshaft are disclosed. The engines may also have non-circular, preferably rectangular, cross-section pistons and cylinders. The pistons may include a skirt with a field of pockets that provide a ringless, non-lubricated, seal equivalent. The pistons also may have a domed piston head with depressions thereon to facilitate the movement of air/charge in the cylinder. The engines also may use multi-stage poppet valves in lieu of conventional poppet valves. The engines may use the pumping motion of the engine piston to supercharge the cylinder with air/charge. The engines also may operate in an inverted orientation in which the piston is closer to the local gravitationally dominant terrestrial body's center of gravity at top dead center position than at bottom dead center position.

The present invention relates to techniques for lowering friction between moving surfaces of, for example, an internal combustion engine. Friction reduction is achieved by adding texture modifications to surfaces that come in contact with each other. Texture modifications that reduce friction in accordance with the present invention include dimples of varying geometries and depths ion the surfaces of components. The present invention also relates to the fabrication technique for applying the texture to the surfaces. In another embodiment, the patterned soft mask is applied onto a large surface (flat or curved including cylindrical rollers surfaces) to be followed by electrochemical etching to imprint the textures onto the component And, in another embodiment, a diamond-like-carbon (DLC) film may be applied to the turbine component to also reduce friction.

The present invention relates to techniques for lowering friction between moving surfaces of, for example, an internal combustion engine. Friction reduction is achieved by adding texture modifications to surfaces that come in contact with each other. Texture modifications that reduce friction in accordance with the present invention include dimples of varying geometries and depths ion the surfaces of components. The present invention also relates to the fabrication technique for applying the texture to the surfaces. In another embodiment, the patterned soft mask is applied onto a large surface (flat or curved including cylindrical rollers surfaces) to be followed by electrochemical etching to imprint the textures onto the component And, in another embodiment, a diamond-like-carbon (DLC) film may be applied to the turbine component to also reduce friction.

A cylinder bore for a cylinder housing of an internal combustion engine may have a cylinder running surface, an upper reversal point and a lower reversal point at which a piston, which may be moved up and down in the cylinder bore and may have piston rings and a piston skirt, may reach a speed which approaches zero during engine operation. The cylinder bore may also have a region between the upper reversal point and the lower reversal point at which the piston may reach a maximum speed during engine operation. The cylinder bore may further have at least two circumferential depressions formed within the region, the at least two circumferential depressions each having a diameter that may be greater than a diameter of the cylinder bore above the region and below the region.

A cylinder bore for a cylinder housing of an internal combustion engine may have a cylinder running surface, an upper reversal point and a lower reversal point at which a piston, which may be moved up and down in the cylinder bore and may have piston rings and a piston skirt, may reach a speed which approaches zero during engine operation. The cylinder bore may also have a region between the upper reversal point and the lower reversal point at which the piston may reach a maximum speed during engine operation. The cylinder bore may further have at least two circumferential depressions formed within the region, the at least two circumferential depressions each having a diameter that may be greater than a diameter of the cylinder bore above the region and below the region.

A bearing assembly comprising a first component and a second component, the first and second components being slidably disposed with respect to each other, wherein the first component slides relative to the second component in a first direction, wherein the first component comprises a plurality of first recesses formed in a first surface facing the second component, wherein the first recesses are distributed in a second direction perpendicular to the first direction with neighboring first recesses being spaced apart in the second direction with a first spacing, wherein the second component comprises a plurality of second recesses formed in a second surface facing the first surface of the first component, wherein the second recesses are distributed in the second direction with neighboring second recesses being spaced apart in the second direction with a second spacing, wherein the first recesses are sized to fit within the second spacings and the second recesses are sized to fit within the first spacings, and wherein the first and second components are urged into a relative position in the second direction in which the first and second recesses do not overlap one another.

An engine includes a cylinder liner and a piston movable within the cylinder liner, a crevice formed between a top land of the piston and the cylinder liner, and an oil entry clearance formed between a top ring of the piston and the cylinder liner. The engine also includes an abnormal combustion inhibitor having an oil recapture surface exposed to the crevice and oriented to limit migration of oil from the crevice toward a combustion chamber in the engine. The abnormal combustion inhibitor includes a groove structure having as a substrate at least one of the cylinder liner or the piston. Related methodology is also disclosed.

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.