A marine engine has a cylinder block defining at least one cylinder bore and a cylinder liner providing a running surface for a piston in the cylinder bore. The cylinder liner is non-axisymmetric relative to a center axis of the cylinder liner. The cylinder block defines a pocket that retains the cylinder liner and prevents the cylinder liner from rotating about the center axis. Novel cylinder liners, assemblies and methods are provided for forming a marine engine having the cylinder block with the cylinder liner formed therein.

An internal combustion engine includes an engine block, a piston, a cylinder head, and a valve train. The engine block includes a cylinder block including a cylinder bore and a crankcase defining a crankcase chamber with a crankshaft positioned within the crankcase chamber. The piston is coupled to the crankshaft and configured to reciprocate within the cylinder bore. The cylinder head is coupled to the cylinder block. The valve train includes a camshaft, a first and second pushrod, a first and second rocker arm, an exhaust valve housed, and an intake valve. The first rocker arm, the second rocker arm, the exhaust valve, and the intake valve each include at least a layer of a low friction material. The first and second pushrod each pass through a pushrod seal to prevent fluid from reaching the rocker chamber to fluidly isolate the rocker chamber from the crankcase chamber.

A method of manufacturing an internal combustion engine is provided. The engine includes a cylinder forming member, a piston reciprocatably accommodated in a cylinder, an injector which supplies fuel into a combustion chamber, and a heat insulating layer covering at least a part of a combustion-chamber wall surface and having a lower heat conductivity than the combustion-chamber wall surface. The method includes applying a coating material that is a material of the heat insulating layer to the combustion-chamber wall surface, assembling the piston to the cylinder forming member while the coating material is uncured, and heating the coating material to be cured by combusting the fuel injected from the injector and reciprocating the piston. The heating the coating material includes injecting the fuel from the injector at least in an early stage of the heating so that the injected fuel adhering to the surface of the coating material is suppressed.

An anti-polish ring for an internal combustion engine is provided. The anti-polish ring includes an axially extending ring portion that is configured to scrape a top portion of a piston in a cylinder liner. The anti-polish ring is configured to accommodate passage of an intake or exhaust valve thereby. The anti-polish ring may include an alignment feature so that the anti-polish ring is inserted in a predetermined orientation in the cylinder. The anti-polish ring may include a heat shield and/or a seating member.

The present disclosure provides a cylinder block for an internal combustion engine having a first cylinder, a first cylinder sleeve, a second cylinder, and a second cylinder sleeve. The first cylinder defines a first cylindrical wall while the second cylinder defines a second cylindrical wall. The first cylinder sleeve lines the first cylindrical wall while the second cylinder sleeve lines the second cylindrical wall. Each of the first and the second cylinder sleeves define a thrust sleeve region, an anti-thrust sleeve region opposite the thrust sleeve region, and a pair of Siamese regions. The outer wall of each of the first and second cylinder sleeves progressively widens toward the top sleeve surface of each of the first and second cylinder sleeves.

A high elastic modulus, high ultimate tensile strength, and low alloy gray cast iron for cylinder liners. The gray cast iron includes from 2.60 wt % to 3.30 wt % Carbon (C); from 1.50 wt % to 2.30 wt % Silicon (Si); from 0.30 wt % to 0.80 wt % Manganese (Mn); from 0.15 wt % to 0.35 wt % Phosphorus (P); from 0.05 wt % to 0.11 wt % Sulphur (S); from 0.60 wt % to 1.20 wt % Copper (Cu); from 0.10 wt % to 0.30 wt % Chromium (Cr); from greater than 0.0 wt % to 0.1 wt % Nickle (Ni); from 0.15 wt % to 0.40 wt % Molybdenum (Mo); and balance wt % Iron (Fe). The total wt % of Si, Mn, P, S, Cu, Cr, Ni, and Mo is less than about 4.10 wt %. The gray cast iron has a Carbon Equivalent (CE) from 3.00 wt % to 3.90 wt % and the product of Mn %*S % is from 0.025 to 0.045.

A cylinder for an internal combustion opposed-piston engine includes a bore, either as part of the cylinder directly or of a liner. The bore has a surface for guiding a pair of pistons disposed for opposing movement in the cylinder. The cylinder bore has three zones of surface finishes: an inner zone extending between and including exhaust and intake ports, where only piston compression rings travel on the bore surface; two instances of an outer zone where only piston oil control rings travel on the bore surface; and two instances of a port zone where both types of rings travel on overlapping paths in the same bore surface portion. Each zone may have a particular surface finish that is tailored to specific requirements including oil control, ring wear, and scuff resistance relevant to the zone.

A cylinder for a V-twin engine includes a section of steel tubing cut to a length. The section of steel tubing includes a first portion having a first wall thickness and a second portion having a second wall thickness less than the first wall thickness. The second wall thickness is less than 0.050 inch. The section of steel tubing includes a first ribbing pattern on an outer surface, within the first portion, and a second ribbing pattern including multiple ribs formed on individual ribs of the first ribbing pattern. A cast body is provided on the first portion of the section of steel tubing so that the section of steel tubing is fixedly secured within the body to form a cylinder sleeve defining a cylinder bore. The second portion having the second wall thickness extends from an end of the body to be received within a bore of a crankcase.

An internal combustion engine with at least one cylinder having a cylinder barrel that forms a guide for a piston associated with the cylinder. The cylinder barrel is only partially formed by a cylinder wall of a crankcase or of a cylinder liner fastened to the crankcase. The cylinder barrel, in a central region as seen in the cylinder axial direction, is formed by the cylinder wall. The cylinder wall, in an upper region of the cylinder barrel adjoining the central region and/or in a lower region adjoining the central region, has an encompassing recess into which is inserted a one-piece or multi-piece annular sliding element, the radially inner wall of which forms a part of the cylinder barrel.

A quick return oil cylinder liner is disclosed. The cylinder liner includes an elongated cylindrical body having an outer surface and an inner surface defining a liner central axis extending between a first liner axial end and a second liner axial end. The inner surface is configured to form a combustion chamber with a piston and an engine housing. A quick oil return part is arranged on the inner surface of the cylinder liner corresponding to a non-skirt part of the piston. The oil return part is positioned below a position of the inner surface corresponding to an oil blade of an oil ring of the piston when the piston is positioned at a bottom dead center position. The oil return part extends to the second linear axial end and forms at opening at the second liner axial end.