Abstract: The ventilator-equipped engine is configured to: guide a blow-by gas generated in a crankcase to an intake passage through an inside of a cylinder head, an inside of a head cover, and a pressure regulating valve; and to directly introduce fresh air into an internal space of the cylinder head by providing a fresh air introduction passage that extends across the intake passage and the cylinder head.

Abstract: A cylindrical part capable of supporting an ignition-coil-integrated plug cap is formed on a head cover so as to correspond to a plug hole of a cylinder head. The cylindrical part is formed by fitting and fixing a pipe material to a mounting hole part formed in the head cover, the mounting hole part facing the plug hole.

Abstract: A cylindrical part capable of supporting an ignition-coil-integrated plug cap is formed on a head cover so as to correspond to a plug hole of a cylinder head. The cylindrical part is formed by fitting and fixing a pipe material to a mounting hole part formed in the head cover, the mounting hole part facing the plug hole.

Abstract: The ventilator-equipped engine is configured to: guide a blow-by gas generated in a crankcase to an intake passage through an inside of a cylinder head, an inside of a head cover, and a pressure regulating valve; and to directly introduce fresh air into an internal space of the cylinder head by providing a fresh air introduction passage that extends across the intake passage and the cylinder head.

Abstract: A blow-by gas return device includes: a gas path which is configured to introduce a blow-by gas generated in a crankcase into an intake system through an inside of a head cover, a pressure control valve and a blow-by pipe; and an orifice provided to the gas path, the orifice mounted on a wall portion of an intake manifold on a cylinder head side. A passage for a blow-by gas is formed in the wall portion on the cylinder head side, and the orifice is formed on a joint pipe mounted on the passage for the blow-by gas for communicably connecting the blow-by pipe with the passage for the blow-by gas.

Abstract: In an engine head cover, an upper portion of a partition plate 5, which partitions an inside of a head cover 3 into upper and lower portions, forms a blowby gas passage W having an inlet 6 and an outlet 7 communicating with an intake path 9. A PCV valve 14 disposed on the outlet 7 side, a filter 13 disposed on the inlet 6 side, and a labyrinth 15 disposed between the PCV valve 14 and the filter 13 are provided. A recovery hole 23 which causes a flowdown of trapped oil is formed at a portion on a downstream side of the filter 13 in a flow direction of a blowby gas in the blowby gas passage W and on a lower side of the labyrinth 15 and the pressure regulating valve 14.

Abstract: A blow-by gas return device includes: a gas path which is configured to introduce a blow-by gas generated in a crankcase into an intake system through an inside of a head cover, a pressure control valve and a blow-by pipe; and an orifice provided to the gas path, the orifice mounted on a wall portion of an intake manifold on a cylinder head side. A passage for a blow-by gas is formed in the wall portion on the cylinder head side, and the orifice is formed on a joint pipe mounted on the passage for the blow-by gas for communicably connecting the blow-by pipe with the passage for the blow-by gas.

Abstract: In an engine head cover, an upper portion of a partition plate 5, which partitions an inside of a head cover 3 into upper and lower portions, forms a blowby gas passage W having an inlet 6 and an outlet 7 communicating with an intake path 9. A PCV valve 14 disposed on the outlet 7 side, a filter 13 disposed on the inlet 6 side, and a labyrinth 15 disposed between the PCV valve 14 and the filter 13 are provided. A recovery hole 23 which causes a flowdown of trapped oil is formed at a portion on a downstream side of the filter 13 in a flow direction of a blowby gas in the blowby gas passage W and on a lower side of the labyrinth 15 and the pressure regulating valve 14.

Abstract: An overhead valve engine has rocker arm pivoted portions (13),(13) oriented substantially in a right and left direction and arranged side by side in a front and rear direction. Each of rocker arm output portions (15),(15) projects from one end portion of each of the rocker arm pivoted portions (13),(13) in a direction opposite to a space between the pivoted portions (13),(13). Each of rocker arm input portions (16),(16) projects from the other end portion of each of the pivoted portions (13),(13) toward the space between the pivoted portions (13),(13). The respective rocker arm input portions (16),(16) are arranged side by side between the rocker arm pivoted portions (13),(13) in the right and left direction.

Abstract: A cylinder body (2) is so formed as to project from a crank chamber (3) in an inclined manner, and a governor gear (50) for driving a centrifugal governor is arranged above a location where a crankshaft (20) is horizontally bridged within the crank chamber (3). An upper wall (71) of the crank chamber (3) is projected upwardly for accommodating the governor gear (50) within the crank chamber (3). An idle gear (45) is arranged at a location above the crankshaft (20) and below the cylinder (46) within the crank chamber (3), and the idle gear (45) is engaged with the crankshaft gear (42) and the governor gear (50) to transmit rotation of the crankshaft gear (42) to the governor gear (50).