Methods and systems are provided for a ventilation arrangement. In one example, a system may include a compact ventilation arrangement arranged within a space between an intake manifold and a cylinder head. A pump of the ventilation arrangement arrange adjacent the cylinder head.

An internal combustion engine includes a cylinder head and a cylinder block. The cylinder head includes a first boss cylinder head conduit portion and a first boss cylinder head cavity portion. The first boss cylinder head conduit portion is configured to receive a first fastener without threadably engaging the first fastener. The first boss cylinder head conduit portion has a first diameter. The first boss cylinder head cavity portion is aligned with the first boss cylinder head conduit portion. The first boss cylinder head cavity portion is configured to receive the first fastener without threadably engaging the first fastener. The first boss cylinder head cavity portion has a second diameter greater than the first diameter. The cylinder block is coupled to the cylinder head. The cylinder block includes a first boss cylinder block threaded portion.

A cooling structure of an internal combustion engine includes a thermostat provided to switch circulation between a radiator passage and a bypass passage in an engine body, to thereby enable acceleration of early warming up via the bypass passage without impairing the external appearance or increasing the size of the internal combustion engine. The cooling structure also includes an in-cylinder-block fluid passage partitioned up and down in an axial direction of a cylinder axis into an in-cylinder-block upper fluid passage and an in-cylinder-block lower fluid passage by a partition wall. The bypass passage is partially composed of the in-cylinder-bock lower fluid passage.

Aspects of the present disclosure are directed to a cylinder housing of an internal combustion engine. In one embodiment of the present disclosure, the cylinder housing includes at least two adjacently arranged cylinders, each of which includes a wet cylinder liner, a support structure, and a coolant jacket arranged between the support structure and the cylinder liner. The cylinder housing further including at least one screw receptacle for a cylinder head screw, and is positioned between at least two adjacently arranged cylinders in a region of at least one engine transverse plane.

A cylinder head cover includes: a body; and a high rigidity part having a higher rigidity than the body; wherein a part between both ends of a fuel pipe is mounted to the high rigidity part.

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In a single cylinder internal combustion engine in which a plug hole is provided striding between a cylinder head and a head cover, and an intake side camshaft and an exhaust side camshaft are disposed at positions sandwiching the plug hole therebetween, a long hole portion formed long in a direction orthogonal to axes of the camshafts is formed as a part of the plug hole. A part of a plurality of cam holder attaching bolts used for fastening the cam holder to the cylinder head are disposed within the long hole portion. A breather chamber disposed around the long hole portion is formed between the head cover and a breather plate attached thereto.

A breather chamber structure for an internal combustion engine wherein the breather chamber can be disposed compactly and the degree of freedom in the layout of the parts of the internal combustion engine can be raised. The breather chamber structure includes a crankcase, a cylinder body provided upwardly on the crankcase, and a breather chamber configured to separate oil from oil mist in the crankcase. The breather chamber includes a crankcase side breather chamber provided in the crankcase and open to a joining plane between the crankcase and the cylinder body, and a cylinder side breather chamber provided in the cylinder body and open to the joining plane.

A camshaft housing includes two longitudinal frame bars and lateral frame bars. The longitudinal frame bars extend in the axial direction of a camshaft. The lateral frame bars extend between the longitudinal frame bars. A bearing portion is arranged in each of the lateral frame bars to rotationally support the camshaft. Each lateral frame bar has a bolt hole to receive a bolt that is inserted through the bolt hole to fix the camshaft housing to a cylinder head body. The bolt hole extends through the lateral frame bar and is arranged on the outer side of the bearing portion in the longitudinal direction of the lateral frame bar. Each longitudinal frame bar has a vibration reducing portion. The cross-sectional area of the longitudinal frame bar gradually changes in the longitudinal direction of the longitudinal frame bar.

A coupling mechanism for a sealing structure having interacting seals in non-parallel planes includes a male portion of a mechanical joint and a female portion of the mechanical joint. The male portion is coupled with a first sealing member contained in a first plane. The female portion is coupled with a second sealing member which is contained in a second plane. The second plane is different from the first plane. The male portion and the female portion of the mechanical joint are configured to mate for coupling the first sealing member with the second sealing member.

A camshaft module may include a module body in which at least one camshaft for controlling valves for a charge cycle of an internal combustion engine is accommodated. The camshaft may comprise a support shaft and sliding cam pieces that are accommodated on the support shaft so as to be displaceable in an axial direction of the support shaft. A support element may also be provided on which actuators for the axial displacement of the sliding cam pieces are accommodated. The support element may extend in the axial direction and therefore parallel to the support shaft. In some cases, a coefficient of thermal expansion of the support element substantially corresponds to a coefficient of thermal expansion of the support shaft.