To provide a running gear structure of an internal combustion engine capable of reducing the size of the internal combustion engine. In a running gear structure of an internal combustion engine including a supercharger and a supercharger driving mechanism transmitting power to the supercharger and driving the supercharger, the supercharger driving mechanism is provided with driving force transmission members (a third intermediate gear and a fourth intermediate gear) disposed on a side opposite to cylinders of the internal combustion engine across valve trains driving a valve gear using, as a power supply, driving force of the crankshaft rotated by explosion in the cylinders. The valve train is disposed closer to an inner side of the internal combustion engine.

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.

An oil mist separator includes a case, an oil collecting portion, and a gradual change portion. The case includes a case main body, an inlet for blow-by gas provided on an upstream side of the case main body in a flowing direction of the blow-by gas, and an outlet for blow-by gas provided on a downstream side in the flowing direction of the case main body. The oil collecting portion is accommodated in the case main body. The gradual change portion is provided in the case and is located in at least one of a space between the inlet and the oil collecting portion in the flowing direction and a space between the oil collecting portion and the outlet in the flowing direction. A cross-sectional flow area of the gradual change portion is gradually decreased as a distance from the oil collecting portion in the flowing direction increases.

In a breather device of an internal combustion engine, a breather chamber is defined by a head cover main body and a chamber forming member. The breather device includes an upstream breather passage communicating a first end of the breather chamber with a crank chamber, a downstream breather passage communicating a second end of the breather chamber with an intake passage, an oil return passage formed in a cylinder head to communicate a valve actuation chamber with the crank chamber, a first communication hole formed in a lower part of a recessed part of the breather chamber adjoining the first end of the breather chamber to communicate the breather chamber with the valve actuation chamber, and a second communication hole formed in a part of the breather chamber downstream of the first communication hole to communicate the breather chamber with the valve actuation chamber.

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.

The disclosure prevents oil separated from blow-by gas by using a breather chamber and discharged to a valve chamber from leaking to the outside from a breather chamber mounting surface between the breather chamber and the valve chamber. A breather chamber includes cylindrical drain passages communicating with a valve chamber, and tips of the drain passages exceed breather chamber mounting surfaces of a cylinder head and a head cover and protrude from opening parts toward a side of the valve chamber, so the oil separated from the blow-by gas in the breather chamber can be reliably discharged to the valve chamber and prevented from leaking to the outside from the breather chamber mounting surfaces.

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.

In an internal combustion engine, the cylinder block includes a first blowby gas passage and a first oil return passage. The cylinder head includes a second blowby gas passage connecting the first blowby gas passage with a connection passage connected with a gas-liquid separator, an oil return chamber separated from a valve operating chamber and the second blowby gas passage by first and second partition walls, respectively, and provided with a first oil return hole connected with the gas-liquid separator, and a second oil return passage connecting the valve operating chamber with the first oil return passage. The first partition wall is formed with a second oil return hole connecting the oil return chamber with the valve operating chamber. The second partition wall is formed with a ventilation hole connecting the oil return chamber with the second blowby gas passage at a higher position than the second oil return hole.

The disclosed subject matter includes an intake manifold for an internal combustion engine that can have a labyrinth structure located therein configured to cause fluids, such as blow-by from engine exhaust, to move in a non-linear direction. The intake manifold can have a plenum including an inlet opening, a plurality of runners, each of the runners extending from the plenum and including a first end opened to the plenum and a second end configured to be connected to the internal combustion engine, and a ventilation chamber, the ventilation chamber extending along each of the runners. The ventilation chamber can include a plurality of ports spaced along the ventilation chamber, each port opens into a respective one of the runners, and a labyrinth inside the ventilation chamber and extending across the ventilation chamber.

Various rotating coalescer elements are described. The rotating coalescer elements include various arrangements of stacked separator discs or cones. In some arrangements, the described rotating coalescer elements include a combination of stacked separator discs or cones and filter media. In some arrangements, the stacked separator discs are designed to provide the largest possible amount of radial-projected separation surface area in a given rotating cylindrical volume, where flow to be cleaned is passing radially (outwardly or inwardly) through the rotating coalescer element. In some arrangements, this is achieved by stacking non-conical separating plates containing various area-maximizing features (e.g., spiral ribs, axial cylinders, spiral grooves, or spiral V shapes).