Abstract: A cylinder assembly with a cylinder liner and a sleeve is provided that includes features that reduce coolant flow stagnation. The sleeve encloses a center section of the cylinder liner to form cooling channels that removes excess heat from the combustion area of the cylinder. The cylinder liner includes features for cooling between bridges in the cylinder's exhaust port.

Abstract: A parent bore cylinder block of an internal combustion, opposed-piston engine includes cooling passages that are formed using a 3-D printed casting core. The casting core can include portions that are ceramic. The parent bore cylinder block can include multiple cylinders, each cylinder with cooling passages and turbulence inducing features in those cooling passages, particularly surrounding the central portions of the cylinders.

Abstract: The invention relates to a liquid-cooled internal combustion engine comprising at least one cylinder block which has a cooling jacket (1) and comprises multiple cylinders (2). The cooling jacket (1) has a base (3) facing a crankcase and a cover (4) facing a cylinder head sealing plane (4a), and the base (3) has an undulating course when seen in a lateral view of the cylinder block. A first spacing (H2) between two adjacent cylinders (2) in the region of at least one first motor transverse plane (8) is larger than a second spacing (H2) between the base (3) of the cooling jacket (1) and the cover (4) in the region of at least one second motor transverse plane (10) containing the cylinder axis (9) when measured in the direction of the cylinder axis (9) in both cases.

Abstract: 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.

Abstract: A cylinder cooling construction includes a cylinder liner with a sidewall, exhaust and intake ports opening through the sidewall, a bore, and a plurality of feed channels that are formed with and extend along the sidewall from a central band of the cylinder toward the exhaust and intake ports. A sleeve covering the sidewall includes a plurality of impingement jet ports that are arranged in at least one sequence extending around the central band and that are in liquid communication with the plurality of feed channels. An annular member disposed between the liner and the sleeve reinforces the central band. The sleeve further includes an inside surface with spaced-apart annular recesses that with the sidewall define liquid coolant reservoirs in the vicinity of the ports that are in liquid communication with the feed channels.

Abstract: The structure of a cylinder with longitudinally-separated exhaust and intake ports includes a powdered metal (PM) ring sintered over grooves and/or slots in the exhaust port bridges and/or the top center (TC) portion of a cylinder liner.

Abstract: Leakage of a liquid (e.g. a coolant and/or a lubricant) past a sleeve valve to a port in communication with a combustion chamber of an internal combustion engine can be prevented by use of a substantially ring-shaped seal, which can be carried on the sleeve valve or disposed on a stationary part of the internal combustion engine.

Abstract: A cylinder block side drain is provided in a cylinder block and a crankcase side drain is provided in a crankcase. A jacket cover is provided in an water jacket of the cylinder block. The jacket cover is pressed against the wall of the water jacket on the crankcase side. When discharging the coolant, the water jacket is opened by pushing the jacket cover inward using a coupler and the coolant is discharged to the outer side of the crankcase via the coupler.

Abstract: An engine assembly includes a coolant pump, an engine structure, a radiator supply feed and a radiator bypass feed. The engine structure defines a first set of cylinders, a first coolant return gallery and a first cooling jacket. The first coolant return gallery extends in a longitudinal direction from a first longitudinal end to a second longitudinal end of the engine structure. The first cooling jacket is in communication with the coolant pump and with the first coolant return gallery. The first coolant return gallery forms a radiator bypass passage providing the coolant fluid to the coolant pump and bypassing the radiator during a first operating condition and forms a radiator supply passage providing the coolant fluid to the radiator during a second operating condition.

Abstract: A handheld work apparatus has an internal combustion engine (9, 9?, 9?) and a starter device (8). The internal combustion engine has a piston (10, 10?) which has at least one piston ring (37, 38). In order to avoid a delay when starting the engine, at least one recess is provided in the cylinder bore (26) which bridges the at least one piston ring (37, 38) in at least one position of the piston (10, 10?) and which has a distance (n, o, p) to all function openings of the engine (9, 9?, 9?) configured in the cylinder bore (26). To reduce the compression in the combustion chamber (25), the piston (10?) has only one piston ring (37) or two piston rings (37, 38) are provided having respective piston ring gaps (39, 40) defining an angle (?) which is up to approximately 45°.

Abstract: An engine block assembly for an internal combustion engine comprises a cylinder portion having a plurality of cylinder walls disposed therein. A water jacket, having opposed side walls, extends about the plurality of cylinder walls to define a coolant flow path. A coolant inlet in fluid communication with the water jacket delivers coolant thereto and a coolant outlet in fluid communication with the water jacket removes coolant therefrom. Opposed sealing shoulders extend into the coolant flow path from the water jacket side walls and a longitudinally extending coolant baffle is disposed in the water jacket adjacent to the sealing shoulders. The coolant baffle includes a baffle sealing face configured to engage the opposed sealing shoulders to direct the coolant entering the water jacket in a single direction around the cylinder walls of the cylinder portion.