A cylinder block for an internal combustion engine includes a metal section and a resin section. The metal section includes: a cylinder liner; head bolt female screw portions that are screwed onto male screw portions of head bolts that fasten the cylinder block and a cylinder head; crank cap bolt female screw portions that are screwed onto male screw portions of crank cap bolts that fasten the cylinder block and crank caps and columnar portions that connect the head bolt female screw portions; and the crank cap bolt female screw portions. The cylinder liner and the columnar portions are integrated with each other.

An improved substrate surface texture i.e., roughness, significantly improves the adhesion of thermal spray coatings. The surface texture is defined by two metrology parameters and the invention comprehends a range of average roughness (Sa) between 9 and 15 μm and developed interfacial area ratio (Sdr) of greater than 100%. This surface texture is achieved by methods such as water jet erosion, mechanical roughening, laser texturing, chemical etching and plasma etching. The surface texture is especially beneficial for walls of cylinders of internal combustion engines, hydraulic cylinders and similar components to which a thermal spray coating is adhered and which are exposed to sliding or frictional wear.

Provided is a cylinder liner which can reduce the friction of the sliding surface from conventional levels and improve fuel efficiency without increasing oil consumption from conventional levels.

When the inner circumferential surface of a cylinder liner or cylinder bore used in an internal combustion engine has a first sliding region, a second sliding region, and a third sliding region, and when respective surface roughness Rvk is from 0.05 μm to 0.3 μm, from 0.4 μm to 1.5 μm, and from 0.15 μm to 0.7 μm, a friction can be reduced while maintaining oil consumption.

A cylinder liner for an opposed-piston engine, and corresponding methods of extending engine durability and thermal management therewith, has opposite ends and a bore with a longitudinal axis for supporting reciprocating movement of a pair of opposed pistons. An intermediate portion of the liner extends between the opposite ends and includes an annular liner portion within which the pistons reach respective TC locations. A liner ring is seated in a portion of the bore in the annular liner portion, between the TC locations, for scraping carbon from top lands of the pistons and/or increasing the thermal resistance of the annular liner portion.

The present invention addresses the problem of providing a cylinder liner or a cylinder bore, which can reduce not only friction on a sliding surface but also oil consumption. In a piston sliding direction of the cylinder bore, grooves of a second sliding region positioned on the side of crankcase have a higher groove area ratio at a depth of 0.3 μm than grooves of a first sliding region positioned on the side of combustion chamber, and the groove area ratio is in a specific range, whereby friction and oil consumption can be reduced.

A cylindrical sleeve for an internal combustion engine is disclosed. The cylindrical sleeve includes a hollow cylindrical sleeve body, extending along an axial direction, with an inner peripheral side that has, along the axial direction, a first axial portion and a second axial portion. The inner peripheral side in the first axial portion is either cylindrical or opens at a first opening angle towards the second axial portion. The second axial portion opens at a second opening angle away from the first axial portion that is greater than the first opening angle. A first surface roughness of the inner peripheral side in the first axial portion is greater than a second surface roughness in the second axial portion.

A cylinder liner of the present invention is a cylinder liner mounted on a cylinder block and formed of flaky graphite cast iron, at least a nitrided layer is provided on an inner periphery of the cylinder liner, and a cross hatching section is formed on the inner periphery, a roughness curve of the inner periphery has a plateau honing shape, a ten-point average roughness Rz of the inner periphery pursuant to JIS B0601:1982 is 4.0 μm or less, and an average value of an area ratio of pits generated in the inner periphery is 8% or less.

Disclosed are a cylinder liner for insert casting and a method for manufacturing the same. In particular, the cylinder liner for insert casting has cooling and warming performances suitable for functions of respective parts by imparting multiple layers having different thermal conductivity on the surface of the cylinder liner for insert casting, such that the cylinder liner can be used for vehicle cylinder blocks.

A cylinder liner assembly for inclusion in the cylinder bore of an internal combustion engine includes a sleeve-like cylinder liner and an anti-polishing ring to scrape combustion deposits from a piston reciprocally movable along an axis line of the cylinder liner. A fire dam may axially protrude from a first liner end of the cylinder liner and may have an obliquely angled chamfer disposed therein circumscribing the axis line. To locate the anti-polishing ring proximate to the top land of the piston when at the top dead center position, the anti-polishing ring can include a cuff header disposed at the first cuff end that is generally triangular and has an angled undercut corresponding to the obliquely angled chamfer. When mated, the chamfer and angled undercut abut against each other.

A cylinder liner for internal combustion engines has an outer roughened surface that has particularly good adherence properties. The surface has is covered with protrusions or spines of varying shapes and sizes, which are created by spraying the mold with a coating and then casting the cylinder liner in the mold. The spines are generally conical or needle-shaped, with the bases being larger than the tips. The spines have an aggregate cross-sectional surface area measured at 0.2 mm from a ground cylindrical surface that is between 50-90% of the total ground cylindrical surface area, and an aggregate cross-sectional surface area measured at 0.4 mm from the ground cylindrical surface that is between 20-45% of the total ground cylindrical surface area.