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 oil separator includes a casing that has an inlet for air and an outlet for air, and an impingement member that is provided inside the casing. Air that contains oil is introduced through the inlet into the casing and caused to strike the impingement member so that the oil is separated from the introduced air and is recovered. The outlet opens in the horizontal direction of the casing. The oil separator further includes an L-shaped elbow member that is attached to the outlet. The elbow member protrudes in the horizontal direction from the outlet and is bent upward.

An oil mist separator includes a housing and an oil separating part which separates oil mist in blow-by gas. The oil separating part is composed of a first oil separating part and a second oil separating part. The housing is provided inside with a partition wall which defines chambers formed for the respective oil separating parts, and second nozzles which jet out blow-by gas are provided in a second partition wall which defines a second chamber in which the downstream-side second oil separating part is provided. The second nozzles can serve, for example, as passages for discharging the oil separated by the second oil separating part toward a drain pipe which is provided in a first chamber.

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.

An oil separator includes a case that has an inflow port, an outflow port, and an oil separation portion. The case has a first wall portion and a second wall portion that constitute a flow channel, and a partition wall portion that connects the first wall portion and the second wall portion. The partition wall portion partitions the flow channel into an upstream-side flow channel and a downstream-side flow channel. The oil separation portion has a constriction hole and a step portion. The step portion has a collision face located on the axis of the constriction hole and configured such that blow-by gas that passes through the constriction hole collides against the collision face, and allows oil that collects on the step portion to be discharged into the upstream-side flow channel through the constriction hole.

The oil mist separator separates oil from blow-by gas which flows through a gas flow passage. A chamber, which is partitioned from the gas flow passage including a gas introduction port, is provided between a cylinder head cover and a baffle plate. A first guide wall, which extends with a downward inclination toward the chamber so as to cover the gas introduction port and the chamber, is provided above the gas introduction port and the chamber. A drain hole for discharging the oil within the chamber is formed in the baffle plate.

An engine is provided where oil is minimally blown off through a breather chamber. The breather chamber includes a plurality of breather inlet chambers each having a breather inlet which opens on a bottom wall; an oil separation chamber where blow-by gases flown out from the breather inlet chambers merge together and oil separation is performed; and a breather outlet. A ceiling wall of each breather inlet chamber is lower than a ceiling wall of an oil separation chamber. It is preferable that the respective breather inlet chambers each have: a remote-side chamber portion disposed remote from the oil separation chamber and a near-side chamber portion disposed near to the oil separation chamber. A ceiling wall of the near-side chamber portion is disposed lower than a ceiling wall of the remote-side chamber portion with a stepped portion formed between the ceiling wall and the ceiling wall.

An oil and gas separation device for an internal combustion engine includes a first chamber, a second chamber, and a third chamber provided successively from bottom to top, wherein the first chamber is connected to the second chamber through a first gas channel. The second chamber is connected to the third chamber through a second gas channel. The third chamber is connected to a gas outlet pipe. A bottom of the first chamber is connected to an internal combustion engine body. A lower oil baffle plate is provided between the bottom of the first chamber and the internal combustion engine body. The first gas channel is longitudinally covered by the lower oil baffle plate. The oil and gas separation effect and speed can be improved by employing the oil and gas separation device for the internal combustion engine of the present disclosure.

The present invention provides an oil separator that can improve oil separation performance with a simple structure. An oil separator includes a casing that has an inlet and an outlet and the oil separator is configured to separate oil contained in blow-by gas in the casing. The casing includes therein multiple staggered partition walls to form a gas passage through which the blow-by gas flows in a meandering manner in a horizontal direction from the inlet to the outlet, and a filter element that partially closes the gas passage and crosses the partition walls.