In an internal combustion engine, an oil return passage extending from a breather chamber can be formed without increasing the number of component parts and without increasing the size of the internal combustion engine. The internal combustion engine (1) comprises an engine block (30) defining a cylinder (2); a case member (19) fastened to a lower part of the engine block to define a crank chamber jointly with the engine block; a bearing member (50) fastened to the engine block in the crank chamber to rotatably support a crankshaft; a breather chamber (113) defined in the engine block; an inlet passage (112) formed in the engine block to communicate the crank chamber with the breather chamber; a connection pipe (114) communicating the breather chamber with an intake device; and an oil return passage (150) formed at least in the bearing member, and extending from a bottom part of the breather chamber to an oil return port (147) opening at an outer surface of the bearing member. The oil return port may be provided in a lower part of the bearing member.

A positive crankcase ventilation valve for an engine is provided with a valve body defining apertures fluidly coupling a crankcase and an intake manifold of the engine, with each aperture sized to prevent an entrained oil droplet from flowing therethrough. The valve has a valve element supported by the body to selectively cover at least one of the apertures in response to a pressure difference between the manifold and the crankcase to provide variable air flow from the crankcase to the intake manifold. A method includes, in response to an increasing absolute pressure difference between the manifold and the crankcase, passively moving a valve element to selectively cover apertures fluidly coupling the crankcase and the manifold to control an air flow from the crankcase to the intake manifold to a predetermined variable flow profile, and separating oil droplets from the air flow via the apertures.

An internal combustion engine is provided with: two intake pipe portions for guiding intake air to two banks; and a blow-by gas recirculation pathway for leading blow-by gas to the two intake pipe portions from a cylinder head or a crank case that includes the two banks. The blow-by gas recirculation pathway includes a distribution passage which is provided between the two intake pipe portions, and which distributes the blow-by gas and allows the same to flow to the two intake pipe portions.

The invention provides a system for ventilation of a crankcase (217) of an internal combustion engine, the system comprising—an air inlet guide (203, 212) adapted to guide air to at least one cylinder (220) of the engine,—a closed circuit conduit (209) for guiding crankcase gas from the crankcase (217) to the air inlet guide (203, 212),—wherein the system comprises gas detection means (2181, 2182, 2183) positioned in the air inlet guide (203, 212), for detecting crankcase gas in the air inlet guide.

A pollution control system for a diesel engine includes a PCV valve and an associated vacuum pump having an inlet and an outlet adapted to vent blow-by gas out from a crankcase to an intake manifold on the diesel engine. The vacuum pump associated with the PCV valve selectively modulates vacuum pressure to adjustably increase or decrease a fluid flow rate of blow-by gas venting from the crankcase through the PCV valve.

A housing of a compressor for an internal combustion engine is provided. The housing includes a first air inlet portion. Further, housing includes a tubular wall defining an annular chamber along a circumference of the first air inlet portion. Tubular wall comprising a second air inlet portion. Housing further includes an opening formed in a wall of first air inlet portion, contiguously extending along the circumference of the first air inlet portion, to fluidly couple the annular chamber with the first air inlet portion. The opening being formed at an offset from the second air inlet portion. The opening defines a first edge and a second edge in the wall of the first air inlet portion. The first edge and the second edge are radially offset from each other with respect to a central axis of the first air inlet portion.

A pneumatically actuated vacuum pump is disclosed. The pneumatically actuated vacuum pump includes a body. The body defines at least two converging motive sections each having an outlet end, at least two diverging discharge sections each having an inlet end, and at least one Venturi gap. The Venturi gap is located between the outlet ends of the at least two converging motive sections and the inlet ends of the at least two diverging discharge sections.

The present invention relates to an oil tank ventilation device for a hydraulic brake unit of a tramcar, comprising a vent plug, a sealing ring, a gas guide hole and a gas guide pipe; the gas guide hole is a through-hole structure arranged at an upper end inside an integrated valve block; the communications of electrical element protection case, integrated valve block and the oil tank are realized by the gas guide pipe stretched into an air chamber of the oil tank and by the vent plug configured in the electrical element protection case. When the surface of the oil tank is covered with ice or snow, the rain or snow can be effectively prevent from falling on the vent plug body and the driving safety of the train is ensured.

Provided is an oil separator having a high efficiency in removing oil particles of relatively large sizes. A blow-by gas passage of the oil separator (2) includes an upstream passage (18) and a downstream passage (20) extending at an angle to the upstream passage. A separation wall (36) provided in the downstream passage includes a first surface (40, 78) forming an obtuse angle relative to the upstream passage, and a second surface (42) adjoining the first surface on a downstream side thereof and defining a planar surface extending substantially perpendicularly to the upstream passage. The blow-by gas is accelerated in the upstream passage, and the flow direction of the blow-by gas is changed by the first surface without substantially changing the flow speed and without disturbing the flow before the blow-by gas flows along the second surface. At this time, the oil particles in the blow-by gas collide with and are trapped by the second surface owing to the inertia of the oil particles.

A separator device for a system for recirculation of the blow-by gases of an internal combustion engine includes a casing containing a separation chamber and having an inlet for communication with the engine crankcase and an outlet for communication with the engine intake manifold, and drainage outlets ending in the engine crankcase, for returning the liquid separated in the separation chamber into the engine crankcase. Actuator means sensitive to pressure in the engine crankcase are associated to the inlet and to the drainage outlets so that when the pressure in the engine crankcase is higher than the pressure in the separator device, the inlet is open and the drainage outlets are closed, while when the pressure in the engine crankcase is lower than the pressure in the separator device, the inlet is closed and the drainage outlets are open.