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.

Provided is a method for preventing the accumulation of cylinder oil at scavenging ports of low-speed marine engines. An oil passage is provided on a cylinder wall inside a cylinder. The oil passage includes multiple oil storage grooves processed in a circumferential direction of the cylinder wall. The oil passage is formed by obliquely extending from the inner side of the cylinder wall to the outside of the cylinder in a radial direction of the cylinder. The scavenging ports are uniformly distributed in a circumferential direction of the cylinder wall, and each of the oil storage grooves is correspondingly processed at an upper portion of the scavenging port upper edge of the scavenging port. Each of the oil storage grooves has a shape matching the curved surface of the scavenging port upper edge.

Provided is a method for preventing the accumulation of cylinder oil at scavenging ports of low-speed marine engines. An oil passage is provided on a cylinder wall inside a cylinder. The oil passage includes multiple oil storage grooves processed in a circumferential direction of the cylinder wall. The oil passage is formed by obliquely extending from the inner side of the cylinder wall to the outside of the cylinder in a radial direction of the cylinder. The scavenging ports are uniformly distributed in a circumferential direction of the cylinder wall, and each of the oil storage grooves is correspondingly processed at an upper portion of the scavenging port upper edge of the scavenging port. Each of the oil storage grooves has a shape matching the curved surface of the scavenging port upper edge.

A cylinder liner for an internal combustion engine may include a hollow-cylindrical liner body, which may have an inner circumferential surface including a first axial portion and a second axial portion. The first axial portion may open at a first opening angle towards the second axial portion. The second axial portion may open at a second opening angle away from the first axial portion. The second opening angle may be greater than the first opening angle. A first surface roughness in the first axial portion may be greater than a second surface roughness in the second axial portion. A plateau aspect in the second axial portion, which may be defined as R3p=Rvk/(Rpk+Rk), may be 0.2 to 1.6. A texture height in the second axial portion, which may be defined as R3k=Rpk+Rk+Rvk, may be 0.4 μm or less.

Methods and systems are provided for a bore. In one example, a system includes a bore portion for receiving a reciprocating piston, the bore portion having first and second ends between which the piston travels in an axial direction. The bore portion comprises a plurality of recesses, axially spaced apart, and formed in a piston facing surface of the bore portion at a plurality of axial positions, with at least one recess being provided at each axial position. Widths of the plurality of recesses decrease in the axial direction away from a mid-stroke position toward the first and second ends, and depths of the plurality of recesses increase in the axial direction away from the mid-stroke position toward the first and second ends.

A piston includes an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, and a circumferential direction. The crown portion includes a top squish surface, and a circumferential annular wall extending downwardly axially from the top squish surface as well as a skirt. A first piston ring receiving groove is spaced away from the top squish surface, an upper land and a lower land extend from the first piston ring receiving groove, and a bottom blend connects the lower land to the first piston ring receiving groove.

A piston includes an annular body including a crown portion defining a longitudinal axis, a radial direction perpendicular to the longitudinal axis, and a circumferential direction. The crown portion includes a top squish surface, and a circumferential annular wall extending downwardly axially from the top squish surface as well as a skirt. A first piston ring receiving groove is spaced away from the top squish surface, an upper land and a lower land extend from the first piston ring receiving groove, and a bottom blend connects the lower land to the first piston ring receiving groove.

A reciprocating machine incltides a cylinder including an internal cylinder wail, a piston movable in the cylinder between a top position and a. bottom position, the piston, comprising an upper ring pack and a lower ring pack disposed around a circumference of the piston and spaced from each other by a first distance, and a circumferential collector groove in the cylinder wall in a position that is above the lower ring pack when the piston is in the top position and that is below the upper ring pack when the piston is in the bottom position, the collector groove including at least” one hole eonneciabie to a conduit for comieciion to a sump. A helical groove can also be provided in the cylinder wall.

A reciprocating machine incltides a cylinder including an internal cylinder wail, a piston movable in the cylinder between a top position and a. bottom position, the piston, comprising an upper ring pack and a lower ring pack disposed around a circumference of the piston and spaced from each other by a first distance, and a circumferential collector groove in the cylinder wall in a position that is above the lower ring pack when the piston is in the top position and that is below the upper ring pack when the piston is in the bottom position, the collector groove including at least” one hole eonneciabie to a conduit for comieciion to a sump. A helical groove can also be provided in the cylinder wall.

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.