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 lower water jacket of a cylinder head includes a lower/upper exhaust collecting portion cooling portion configured between a lower exhaust collecting portion and an upper exhaust collecting portion by bypassing a lower exhaust collecting portion cooling portion. Besides, cooling water flowing through the lower/upper exhaust collecting portion cooling portion is merely cooling water of the lower water jacket, and cooling water of an upper water jacket does not flow through the lower/upper exhaust collecting portion cooling portion. Therefore, in the lower/upper exhaust collecting portion cooling portion, interference may not occur in cooling water of the two water jackets to restrain smooth flowing, and cooling effects of an area sandwiched by the lower exhaust collecting portion and the upper exhaust collecting portion are further improved.

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 lower water jacket of a cylinder head includes a lower/upper exhaust collecting portion cooling portion configured between a lower exhaust collecting portion and an upper exhaust collecting portion by bypassing a lower exhaust collecting portion cooling portion. Besides, cooling water flowing through the lower/upper exhaust collecting portion cooling portion is merely cooling water of the lower water jacket, and cooling water of an upper water jacket does not flow through the lower/upper exhaust collecting portion cooling portion. Therefore, in the lower/upper exhaust collecting portion cooling portion, interference may not occur in cooling water of the two water jackets to restrain smooth flowing, and cooling effects of an area sandwiched by the lower exhaust collecting portion and the upper exhaust collecting portion are further improved.

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 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.