A positive crankcase ventilation (PCV) system includes: an oil separator separating oil from blow-by gases; a PCV valve allowing the blow-by gases from which the oil has been separated by the oil separator to flow into intake ports of a cylinder head; a PCV passage vertically extending from the PCV valve; a PCV chamber connected to the PCV passage; and a plurality of bypass passages branching off from the PCV chamber to the intake ports, respectively.

A valve apparatus designed to control the flow of crankcase gases from a positive crankcase ventilation valve to an intake manifold of an internal combustion engine is provided. The valve apparatus is designed to adjust during idle, cruising, acceleration and wide-open throttle modes of the engine to enhance fuel economy. The valve apparatus includes a valve body having a main inlet coupled to the positive crankcase ventilation valve and a main outlet, an orifice piston slidably mounted to an interior of the valve body and having an end face with a central hole and a plurality of secondary holes, an end cap coupled to the main outlet of the valve body and intake manifold of the engine, a seal disposed within the end cap and having a central opening, and a spring connected to the orifice piston and seal.

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.

An air cleaner includes: an air cleaner box defining a clean chamber that is placed rearward of a dirty chamber, the clean chamber receiving air which has been introduced from front into the dirty chamber and then filtered through an air cleaner element; and funnels that are to be connected to an intake port of an internal combustion engine, the funnels protruding upward into a space within the air cleaner box from a bottom wall of the air cleaner box. The air cleaner further includes a breather chamber into which blow-by gas is introduced from the internal combustion engine, the breather chamber being placed rearward of the funnels and between the funnels and a rear wall of the air cleaner box. Accordingly, the air cleaner can further promote the air-liquid separation of blow-by gas without incurring an increase in weight of the internal combustion engine.

An internal combustion engine includes on-off valves that configure a closed space by closing an internal space of a breather line, a pump that depressurizes or pressurizes the closed space, a pressure sensor that detects a pressure of the closed space, and an abnormality assessment element that assesses abnormality of the breather line. The abnormality assessment element assesses abnormality of the breather line based on a pressure change of the closed space in a case where the closed space is depressurized or pressurized by the pump.

An internal combustion engine has a tank ventilation system and a crankcase ventilation system. The tank ventilation system is connectable to an intake system downstream of a throttle element via a first non-return valve in a first line and upstream of a compressor via a second non-return valve in a second line and a third non-return valve in a second sub-line. The crankcase ventilation system is connectable to the intake system downstream of the throttle element via a fourth non-return valve in a third line and upstream of the compressor via a fourth line and the third non-return valve. The intake system is connectable to the second line downstream of the throttle element at a transitional point between the second line and the second sub-line via a fifth nonreturn valve in a fifth line. A nozzle is formed at the transitional point from the fifth line to the second line and the second sub-line, and the second line opens into the nozzle downstream of the second non-return valve. A first pressure sensor for measuring the pressure in the second line is provided in the second line between the second non-return valve and the nozzle. Only a single pressure sensor is required to diagnose or detect a leak.

An actuator for a separator for separating contaminants from a fluid stream which includes entrained contaminants. The actuator is arranged to move along an actuator axis to adjust an open cross-sectional area of at least one aperture of the separator, and comprises a flexible diaphragm, and a support assembly for the flexible diaphragm. The support assembly is movable along the actuator axis carrying the flexible diaphragm and has an upper support member mounted on a lower support member. A portion of the flexible diaphragm is located between the upper and lower support members. The lower support member comprises an axially extending support portion coupled to a radially extending support portion. The upper support member comprises a diaphragm anti-inversion feature coupled to a radially extending support portion. The diaphragm anti-inversion feature extends such that it axially overlaps at least part of the axially extending support portion of the lower support member.

A diagnostic system and method for a crankcase ventilation system of an engine having a boost system utilize a pressure sensor configured to measure a pressure in a make-up air (MUA) hose, a flow-limiting valve (i) fixedly attached to the induction system at a point upstream from the pressure sensor and proximate to an induction system end of the MUA hose and (ii) configured to limit flow through the MUA hose, and a controller configured to, in response to detecting the non-boost operating condition of the engine, obtain an initial pressure from the pressure sensor and then command the flow-limiting valve to close for a diagnostic period, during which monitor the pressure is monitored to determine a pressure drop from the initial pressure, and when the pressure drop fails to exceed a threshold during the diagnostic period, detect a malfunction indicative of a leaking or disconnected MUA hose.

A diffuser for a jet pump of a separator comprises an inlet defining a first flow area; an outlet in fluid communication with the inlet through which fluid exits the diffuser, in which a flow path extends from the inlet to the outlet, and in which the outlet defines a second flow area greater than the first flow area so that a velocity of fluid flowing through the inlet is greater than a velocity of fluid flowing through the outlet; and a communication port extending through a wall of the diffuser with an inlet in communication with an interior of the diffuser and an outlet in communication with an exterior of the diffuser, in which the communication port inlet is between the diffuser inlet and the diffuser outlet, so that contaminants separated from the fluid stream are removed through the communication port.

A diagnostic system and method for a crankcase ventilation system of an engine having a boost system utilize a pressure sensor configured to measure a pressure in a make-up air (MUA) hose, a flow-limiting valve (i) fixedly attached to the induction system at a point upstream from the pressure sensor and proximate to an induction system end of the MUA hose and (ii) configured to limit flow through the MUA hose, and a controller configured to, in response to detecting the non-boost operating condition of the engine, obtain an initial pressure from the pressure sensor and then command the flow-limiting valve to close for a diagnostic period, during which monitor the pressure is monitored to determine a pressure drop from the initial pressure, and when the pressure drop fails to exceed a threshold during the diagnostic period, detect a malfunction indicative of a leaking or disconnected MUA hose.