A head cover structure (45) for an internal combustion engine (1) comprises a head cover (4) connected to a cylinder head (3), and an auxiliary cover (44) connected to the head cover and defining a gas-liquid separation passage (74) jointly with the head cover, the gas-liquid separation passage being communicated with a crankcase chamber (11) of the internal combustion engine, and configured to separate lubricating oil from a crankcase gas drawn from the crankcase chamber, wherein the auxiliary cover is integrally formed with an intake pipe (49) internally defining a part of an intake passage (20) of the internal combustion engine, and the auxiliary cover internally defines a crankcase gas introduction passage (63) communicating the gas-liquid separation passage with an interior of the intake pipe.

A blow-by gas treatment device for an internal combustion engine includes: a positive crankcase ventilation (PCV) separator configured to be fastened to the internal combustion engine with a plurality of bolts; and one of a single sealant or a plurality of sealants configured to seal gas leakage of blow-by gas from a gap between the internal combustion engine and the PCV separator; wherein the plurality of bolts includes at least one break head bolt and three or more unbreakable head bolts, the unbreakable head bolt being a bolt in which a bolt head is not separated even when a fastening torque corresponding to a tightening torque applied to the break head bolt is applied to the bolt head.

An oil separating device for separating an oil mist from a blow-by gas is arranged on a flow passage of the blow-by gas. The oil separating device includes an oil separator having an inlet formed at one end thereof and an outlet formed at another end thereof opposite to the one end; a collision wall arranged at a downstream side of the oil separator, and including an uneven portion formed on a surface thereof to face the outlet of the oil separator; and a filter arranged between the oil separator and collision wall. The oil separator is formed such that the oil mist in the blow-by gas coalesces together to form a coalesced oil mist, the filter removes the coalesced oil mist from the blow-by gas, and the collision wall separates a remained oil mist remained in the blow-by gas through the filter.

A blow-by gas device of a supercharger-equipped engine includes a blow-by gas passage that introduces blow-by gas into an intake passage via a positive crankcase ventilation (PCV) valve. A supercharger has a supercharger rotor provided integrally with a rotation shaft rotatably supported on a bearing part. A space communicating with the bearing part is connected to a communication passage. The communication passage guides the blow-by gas into the space.

A PCED can include an outer can, an upper lid having an upper lid intake and an upper lid exhaust, a lower lid having a lower lid exhaust, and an internal frame disposed within the can. With the internal frame disposed within the can, first, second, third, and fourth chambers can be formed, with the first chamber containing a coalescing material. Gases from a combustion engine crankcase can enter the PCED via the upper lid intake, move through the chambers, and exit the PCED via the upper lid exhaust and return to the crankcase. While moving through the chambers, impurities within the gas convert to liquid form via condensation, collect in the second chamber, and can be subsequently drained from the PCED via the lower lid exhaust.

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 internal combustion engine includes a blow-by gas treating device. The blow-by gas treating device includes a separator having a line connection portion. The line connection portion includes an intake connection union, to which an intake connection line is attached, a sensor connection union, to which a pressure sensor is connected, a partition plate, which divides the space in the separator into a first space and a second space, and a constriction, which is provided in the partition plate and allows the first space and the second space to communicate with each other. The line connection portion is constituted by combining a first unit, which includes the partition plate and defines the first space, and a second unit, which defines the second space with the partition plate of the first unit. The intake connection union and the sensor connection union are provided in the second unit.

A blow-by gas treatment device for an internal combustion engine includes: a positive crankcase ventilation (PCV) separator configured to be fastened to the internal combustion engine with a plurality of bolts; and one of a single sealant or a plurality of sealants configured to seal gas leakage of blow-by gas from a gap between the internal combustion engine and the PCV separator; wherein the plurality of bolts includes at least one break head bolt and three or more unbreakable head bolts, the unbreakable head bolt being a bolt in which a bolt head is not separated even when a fastening torque corresponding to a tightening torque applied to the break head bolt is applied to the bolt head.

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 housing component is provided, the housing component defining two or more drain channels configured to receive oil separated from a crankcase ventilation system and to drain said oil through the housing component, wherein the engine housing component comprises two or more drain features, each of the drain features corresponding to one of the drain channels, wherein each of the drain features is configured to allow an oil drain pipe to be coupled to the drain feature such that the oil drain pipe is in fluid communication with the corresponding drain channel, wherein a first drain feature differs from the or each of the other drain features, such that a particular oil drain pipe configured to couple to the first drain feature is not couplable to the other drain features. An engine housing assembly and kit of oil drain pipes is also provided.