A blowby-gas reflux system 60 has: a blowby-gas reflux path 70; an atmospheric release mechanism 90 that releases, into the atmosphere, blowby gas Gb that has passed through an oil separator 80; and a control device 50. The control device 50 is provided with: a determination unit 51 that determines whether oil caulking occurs in a compressor 41 on the basis of the operating state of the compressor; and a control unit 51 that stops the release of the blowby gas into the atmosphere performed by the atmospheric release mechanism if the determination unit determines that oil caulking does not occur, and that causes the atmospheric release mechanism to release the blowby gas into the atmosphere if the determination unit determines that oil caulking occurs.

Various embodiments include a method for diagnosing a crankcase ventilation line of a crankcase ventilation device for an internal combustion engine having a crankcase, an intake tract, and a compressor arranged in the intake tract for compressing the intake air comprising: diverting fresh air from the intake tract via a fresh air supply line; either enabling or inhibiting a flow of fresh air into a free volume of the crankcase depending on a switch position of a shut-off valve in the fresh air supply line; detecting a nitrogen oxide concentration in the crankcase during the process of crankcase ventilation, close to the point of introduction into the intake tract upstream of the compressor using a nitrogen oxide sensor; and evaluating the tightness of the crankcase ventilation line based at least in part on the detected nitrogen oxide concentration.

In an internal combustion engine, a breather chamber can be formed without increasing the number of component parts. 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 (4) jointly with the engine block; and a bearing member (50) fastened to the engine block in the crank chamber to rotatably support a crankshaft; wherein the engine block is provided with a central recess (134) formed in a part thereof to which the bearing member is fastened, a blow-by gas inlet passage (112, 116, 121) communicating the central recess with the crank chamber, and a blow-by gas return passage (122, 118) forming a part of a passage communicating the central recess with an intake device, the central recess and the bearing member jointly defining a central breather chamber.

The ventilator-equipped engine is configured to: guide a blow-by gas generated in a crankcase to an intake passage through an inside of a cylinder head, an inside of a head cover, and a pressure regulating valve; and to directly introduce fresh air into an internal space of the cylinder head by providing a fresh air introduction passage that extends across the intake passage and the cylinder head.

The invention relates to a single-stage or multistage suction jet pump comprising a propelling nozzle (5), one or more suction nozzles (2), a diffuser (7), and a volume flow limiting valve in or directly in front of the propelling nozzle. The volume flow limiting valve has a valve element (4) in the overpressure region (1) of the suction jet pump, said valve element having an opening (8) with a cross-sectional area which is smaller than the cross-sectional area of the propelling nozzle (5). The valve element spans at least one additional gap opening (9) which first releases the cross-section of the gap opening (9) when the pressure difference between the overpressure region (1) and the suction region (2) increases and which switches in the event of a defined large pressure drop and the valve element (4) reduces or closes the cross-section of the gap opening (9) such that the volume flow flowing over the opening (8) is limited to a defined level even in the event of a further increasing pressure difference.

An abnormality determination apparatus for an internal combustion engine in which an intake passage upstream of a supercharger and a crankcase are connected by a breather line includes: an intake flow rate detection unit that detects an intake flow rate in the intake passage; and an abnormality determination unit that determines abnormality of the breather line. The abnormality determination unit accumulates a time for which a rotation second-order component of a fluctuation waveform of the intake flow rate is equal to or more than a threshold over a predetermined period of time and determines the abnormality of the breather line when the accumulated value is less than a predetermined accumulation threshold.

The invention relates to a single-stage or multistage suction jet pump comprising a propelling nozzle (5), one or more suction nozzles (2), a diffuser (7), and a volume flow limiting valve in or directly in front of the propelling nozzle. The volume flow limiting valve has a valve element (4) in the overpressure region (1) of the suction jet pump, said valve element having an opening (8) with a cross-sectional area which is smaller than the cross-sectional area of the propelling nozzle (5). The valve element spans at least one additional gap opening (9) which first releases the cross-section of the gap opening (9) when the pressure difference between the overpressure region (1) and the suction region (2) increases and which switches in the event of a defined large pressure drop and the valve element (4) reduces or closes the cross-section of the gap opening (9) such that the volume flow flowing over the opening (8) is limited to a defined level even in the event of a further increasing pressure difference.

A blow-by gas return device includes: a gas path which is configured to introduce a blow-by gas generated in a crankcase into an intake system through an inside of a head cover, a pressure control valve and a blow-by pipe; and an orifice provided to the gas path, the orifice mounted on a wall portion of an intake manifold on a cylinder head side. A passage for a blow-by gas is formed in the wall portion on the cylinder head side, and the orifice is formed on a joint pipe mounted on the passage for the blow-by gas for communicably connecting the blow-by pipe with the passage for the blow-by gas.

A hybrid vehicle includes: a crankcase extending from a lower portion of a cylinder of an engine, the crankcase including a main body portion defining a crank chamber in which a crankshaft of the engine is accommodated, the crankcase further including a breather portion projecting upwardly from the main body portion and defining a breather chamber into which blowby gas is introduced from the crank chamber; a breather tube that introduces the blowby gas from the breather chamber into the intake passage; and a drive motor disposed rearwardly of the cylinder and mounted on a top surface of the crankcase. The breather portion has a facing surface facing an outer peripheral surface of the drive motor. The facing surface of the breather portion is shaped to conform to the outer peripheral surface of the drive motor.

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.