Abstract: To improve the oil separation performance in an oil separation device for an internal combustion engine. The oil separation device (10) comprises a gas liquid separation passage (56) internally defined by a lower wall, an upper wall and a pair of side walls, and extending in a horizontal direction, a gas inlet (54) and a gas outlet (63) provided on either end of the gas liquid separation passage, a plurality of lower partition walls (56H) projecting upward from the lower wall, and a plurality of upper partition walls (56J) projecting downward from the upper wall. The lower partition walls and the upper partition wall are tilted with respective the length wise direction in plan view so as to define a spiral passage. The lower wall is inclined with respect to a horizontal plane such that an upstream part of the lower wall is lower than a downstream part of the lower wall with respect to a direction of the swirl flow.

Abstract: To improve the oil separation performance in an oil separation device for an internal combustion engine. The oil separation device (10) comprises a gas liquid separation passage (56) internally defined by a lower wall, an upper wall and a pair of side walls, and extending in a horizontal direction, a gas inlet (54) and a gas outlet (63) provided on either end of the gas liquid separation passage, a plurality of lower partition walls (56H) projecting upward from the lower wall, and a plurality of upper partition walls (56J) projecting downward from the upper wall. The lower partition walls and the upper partition wall are tilted with respective the length wise direction in plan view so as to define a spiral passage. The lower wall is inclined with respect to a horizontal plane such that an upstream part of the lower wall is lower than a downstream part of the lower wall with respect to a direction of the swirl flow.

Abstract: To improve the oil separation performance in an oil separation device for an internal combustion engine. The oil separation device (10) comprises a gas liquid separation passage (56) internally defined by a lower wall, an upper wall and a pair of side walls, and extending in a horizontal direction, a gas inlet (54) and a gas outlet (63) provided on either end of the gas liquid separation passage, a plurality of lower partition walls (56H) projecting upward from the lower wall, and a plurality of upper partition walls (56J) projecting downward from the upper wall. The lower partition walls and the upper partition wall are tilted with respective the length wise direction in plan view so as to define a spiral passage. The lower wall is inclined with respect to a horizontal plane such that an upstream part of the lower wall is lower than a downstream part of the lower wall with respect to a direction of the swirl flow.

Abstract: To improve the oil separation performance in an oil separation device for an internal combustion engine. The oil separation device (10) comprises a gas liquid separation passage (56) internally defined by a lower wall, an upper wall and a pair of side walls, and extending in a horizontal direction, a gas inlet (54) and a gas outlet (63) provided on either end of the gas liquid separation passage, a plurality of lower partition walls (56H) projecting upward from the lower wall, and a plurality of upper partition walls (56J) projecting downward from the upper wall. The lower partition walls and the upper partition wall are tilted with respective the length wise direction in plan view so as to define a spiral passage. The lower wall is inclined with respect to a horizontal plane such that an upstream part of the lower wall is lower than a downstream part of the lower wall with respect to a direction of the swirl flow.

Abstract: A camshaft support structure for an internal combustion engine includes a cylinder head, a camshaft, a plurality of bearings, an auxiliary machine drive cam, an auxiliary machine, and a pulsar plate. The plurality of bearings include a terminal bearing supporting the camshaft to be rotatable with respect to the cylinder head about a rotational axis. The auxiliary machine has a plunger provided to be moved forward and backward by the auxiliary machine drive cam. The pulsar plate projects from the camshaft in a radial direction of the camshaft and is provided on an opposite side of the auxiliary machine drive cam with respect to the terminal bearing. The pulsar plate has a second surface facing the terminal bearing in the axial direction. Each of the first surface and the second surface is provided to slidably contact the terminal bearing.

Abstract: A cooling water passage structure in a cylinder head of an internal combustion engine includes a first exhaust-side cooling water passage and a second exhaust-side cooling water passage arranged to sandwich an exhaust collecting portion and extending in a lengthwise direction of the cylinder head. An exhaust pipe is fastened to a exhaust-side lateral surface of the cylinder head via a fastening member. A shunt passage is formed in at least one of the first exhaust-side cooling water passage and the second exhaust-side cooling water passage to cool the fastening member and is formed along a water flow in the first exhaust-side cooling water passage or the second exhaust-side cooling water passage by partly expanding the first exhaust-side cooling water passage or the second exhaust-side cooling water passage to increase a passage cross-sectional area of the first exhaust-side cooling water passage or the second exhaust-side cooling water passage.

Abstract: A detent structure for a rocker shaft includes a camshaft, a rocker shaft, a shaft support, and a detent part. The camshaft is provided at a cylinder head of an engine. The shaft support is provided at the cylinder head to support the rocker shaft and has a support surface supporting the rocker shaft. The detent part is to prevent rotation of the rocker shaft. The detent part includes a bolt insertion hole and a detent bolt. The bolt insertion hole is displaced from a central axis of the rocker shaft and passes through the rocker shaft. The detent bolt is provided in the bolt insertion hole and is fastened to the shaft support to pass across the support surface.

Abstract: A cooling water passage structure in a cylinder head of an internal combustion engine includes a main cooling water passage extending in the lengthwise direction above combustion chambers. An exhaust-side communication passage communicates the main cooling water passage with a first exhaust-side cooling water passage and with a second exhaust-side cooling water passage. A ridge extends in the lengthwise direction to adjust a flow speed of cooling water to flow through the main cooling water passage and is provided on a first wall surface of a main passage defining portion on a side away from the combustion chambers. An exhaust-side throttle portion extends in a direction substantially perpendicular to the lengthwise direction to reduce a passage cross-sectional area of the exhaust-side communication passage and is provided on a second wall surface of an exhaust-side communication passage defining portion on a side away from the combustion chambers.

Abstract: A cooling water passage structure in a cylinder head of an internal combustion engine includes a first exhaust-side cooling water passage and a second exhaust-side cooling water passage arranged to sandwich an exhaust collecting portion and extending in a lengthwise direction of the cylinder head. An exhaust pipe is fastened to a exhaust-side lateral surface of the cylinder head via a fastening member. A shunt passage is formed in at least one of the first exhaust-side cooling water passage and the second exhaust-side cooling water passage to cool the fastening member and is formed along a water flow in the first exhaust-side cooling water passage or the second exhaust-side cooling water passage by partly expanding the first exhaust-side cooling water passage or the second exhaust-side cooling water passage to increase a passage cross-sectional area of the first exhaust-side cooling water passage or the second exhaust-side cooling water passage.

Abstract: A cooling water passage structure in a cylinder head of an internal combustion engine includes a main cooling water passage extending in the lengthwise direction above combustion chambers. An exhaust-side communication passage communicates the main cooling water passage with a first exhaust-side cooling water passage and with a second exhaust-side cooling water passage. A ridge extends in the lengthwise direction to adjust a flow speed of cooling water to flow through the main cooling water passage and is provided on a first wall surface of a main passage defining portion on a side away from the combustion chambers. An exhaust-side throttle portion extends in a direction substantially perpendicular to the lengthwise direction to reduce a passage cross-sectional area of the exhaust-side communication passage and is provided on a second wall surface of an exhaust-side communication passage defining portion on a side away from the combustion chambers.