An engine includes: an exhaust manifold 7 close to one of left and right side surfaces of an engine; a turbocharger 60 having an exhaust-side inlet connected to the exhaust manifold 7; and a rocker-arm-chamber-integrated intake manifold 8 being disposed on an upper surface of a cylinder head 5 and integrally including a rocker arm chamber 90 and an intake manifold 6. The intake manifold 8 has a wall 101 dividing the rocker arm chamber 90 close to the one of the left and right side surfaces of the engine 1 and the intake manifold 6 close to the other of the left and right side surfaces to isolate the rocker arm chamber 90 and the intake manifold 6 from each other. The rocker arm chamber 90 has, in its upper portion, a positive crankcase ventilation device 69 protruding therefrom and being configured to return blowby gas to an intake system. The positive crankcase ventilation device 69 has, in its side surface, a blowby-gas discharge port 67 connected with a gas conduit 68 through which blowby gas is delivered to an intake-side inlet of the turbocharger 60.

An oil separator unit including an upstream member having an opening through which the blowby gas passes, a downstream member having a hit portion hit by the blowby gas, and a porous member trapping the oil mist contained in the blowby gas that has passed through the through hole. The upstream member includes and a spacer projected from an upstream surface facing a first surface of the porous member to support the first surface, the downstream member includes a rib projected from a downstream surface facing a second surface of the porous member to support the second surface, and the spacer is extended along a first direction and the rib is extended along a second direction substantially perpendicular to the first direction.

An inertial gas-liquid impactor separator includes flow director guidance structure directing and guiding flow through the housing from the inlet to the outlet along a flow path from upstream to downstream. The flow director guidance structure may include a flow controller controlling and directing flow.

Methods and systems are provided for a ducted plenum of a positive crankcase ventilation system for an engine. In one example, the ducted plenum may include a plurality of ducts coupled to a central chamber and an oil separator and valve arranged downstream of the central chamber. The ducted plenum may vent gases from an engine crankcase and deliver the vented gases to the engine intake system.

An engine including: an exhaust manifold provided near one side surface of an engine; a turbocharger having an exhaust-side inlet connected to the exhaust manifold; and a rocker-arm-chamber-integrated intake manifold disposed on a cylinder head and integrally including a rocker arm chamber and an intake manifold. The intake manifold has a wall dividing the rocker arm chamber provided near one side surface of the engine and the intake manifold provided near another side surface thereof to isolate the rocker arm chamber and the intake manifold from each other. The rocker arm chamber has, in its upper portion, a positive crankcase ventilation device protruding therefrom and returning blowby gas to an intake system. The positive crankcase ventilation device has a blowby-gas discharge port connected with a gas conduit through which blowby gas is delivered to an intake-side inlet of the turbocharger.

An oil separator is provided, which can accurately control an interval between an introduction hole of a gaseous body and a separation member, and can ensure a stable and high separation performance. An oil separator 30 includes a wall portion 31 having a plurality of orifices 32, and a holding portion 34 holding a separation member 33. A facing surface 33A of the separation member 33 is disposed along a front face portion 42A of a positioning portion 42 having a plurality of opening portions 42D, so that an interval L between the orifices 32 and the facing surface 33A of the separation member 33 accurately has a desired distance. A gas separated from an oil smoothly flows downward along a flow path formed by the opening portions 42D so as to reduce a pressure loss.

An oil separator unit including an upstream member having an opening through which the blowby gas passes, a downstream member having a hit portion hit by the blowby gas, and a porous member trapping the oil mist contained in the blowby gas that has passed through the through hole. The upstream member includes an upstream surface facing a first surface of the porous member and a pair of recesses formed in substantially U-shapes along circumference portions in both end sides on an upstream surface of the upstream member, and the downstream member includes a pair of flange parts formed in substantially U-shapes so as to fit in the pair of recesses.

An engine includes: a throttle body that is joined to an intake port and that makes a butterfly valve within an intake path actuate based on driving force of an electric actuator so as to adjust an opening degree of the intake path; a receptor that extends from the throttle body to a direction distant from the throttle body above a crankcase and that receives the electric actuator therein; and a supporting piece that extends from the receptor to the direction distant from the throttle body and that is supported on the crankcase. Accordingly, in the engine, it is possible to alleviate the influence of vehicle vibrations on the throttle body and actuator by enhancing the rigidity with which to support the throttle body and actuator in a simple structure.

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.

A cylinder head cover structure of an engine includes a positive crankcase ventilation (PCV) valve releasing blow-by gas from an oil separating chamber to an intake system of the engine. The oil separating chamber is included in an oil separator provided to an interior of a cylinder head cover. In the oil separating chamber, oil mist is separated and removed from the blow-by gas. The PCV valve is located between a portion of a defining wall and an exterior wall of the cylinder head cover, and supported by the defining wall and the exterior wall, the defining wall defining the oil separating chamber and the cam housing, and the exterior wall being spaced apart from the portion of the defining wall. The PCV valve is surrounded by a space communicating with the cam housing.