OIL SEPARATION DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

[Problem] To increase oil separation performance in an oil separation device of an internal combustion engine. [Solution] An oil separation device (10) has: a gas-liquid separation passage (56) extending in a horizontal direction, the gas-liquid separation passage (56) being formed of a bottom wall (56A), a top wall (56B), and a pair of side walls (56C, 56D); an aeration hole (54) and a gas circulation port (63) provided at both ends of the gas-liquid separation passage; a plurality of bottom-side partition walls (56H) protruding from the bottom wall; and a plurality of top-side partition walls (56J) protruding from the top wall. The bottom-side partition walls and the top-side partition walls are inclined relative to the longitudinal direction of the gas-liquid separation passage in a plan view, and form a spiraling channel extending in the longitudinal direction inside the gas-liquid separation passage. When the direction of revolution from the aeration hole toward the gas circulation port along the spiraling channel is a forward-revolving direction, the bottom wall is arranged at an incline relative to a horizontal plane so that an upstream-side portion corresponding to the upstream-side in the forward-revolving direction is positioned lower than a downstream-side portion corresponding to the downstream side, as seen from a direction concordant with the longitudinal direction.