Methods and systems are provided for diagnosing a positive crankcase ventilation (PCV) system. In one example, a diagnostic method for a PCV system is provided that includes, when an intake manifold air pressure is above a threshold boost value, determining a PCV system breach based on a pressure determined using a pressure sensor positioned on a clean side of an oil separator coupled to a crankcase and receiving crankcase gas from the crankcase. In the PCV system a ventilation line provides fluidic communication between the oil separator and an intake conduit upstream of a compressor.

A convergent nozzle is in a mixer housing and in a flow path from an air inlet of the mixer to an outlet of the mixer. A convergent-divergent nozzle is in the mixer housing and includes an air-exhaust gas inlet in fluid communication to receive fluid flow from the convergent nozzle and from the interior of the exhaust gas housing. A first nozzle module is configured to be received in the mixer housing and, when received in the mixer housing, define at least a portion of the convergent nozzle or the convergent-divergent nozzle. A second nozzle module is configured to be received in the mixer housing separate from the first nozzle module. The second nozzle module, when received in the mixer housing, is configured to define at least a portion of the convergent or the convergent-divergent nozzle. The second nozzle module has a different flow characteristic than the first nozzle module.

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 value calculated from a rotation second-order component of a fluctuation waveform of the intake flow rate over a predetermined period of time and determines the abnormality of the breather line when the accumulated value is less than a predetermined threshold.

A system in one embodiment includes at least one cylinder, a supplemental boost supply, and a supply line. The at least one cylinder is configured for use in a reciprocating internal combustion engine, and includes a combustion portion and a crank portion on opposite sides of a piston. The at least one cylinder also includes an intake port and an exhaust port in fluid communication with the combustion portion. The supplemental boost supply is configured to provide a supplemental air supply to the combustion portion of the engine when the engine is idling to increase pressure in the combustion portion. The supply line couples the supplemental boost supply to the intake port.

This blow-by gas recirculation device for an internal combustion engine is provided with a vacuum pump which supplies negative pressure to a brake booster and usable for recirculation of blow-by gas to an intake passage. This device includes: a PCV device for recirculating blow-by gas in a crankcase to the intake passage; a ventilation shortage region determination unit which determines whether or not an operational region of the engine is a PCV ventilation flow rate shortage region; and a brake negative pressure determination unit which determines whether or not the negative pressure of the brake booster is secured. The vacuum pump ventilates blow-by gas in the crankcase only when the determination units determines that the operational region is the PCV ventilation flow rate shortage region and that the negative pressure is secured. This reduces a contact risk of blow-by gas with engine oil, and inhibits the degradation of the oil.

Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits.

An oil separation device includes an oil separator in a housing between a gas inlet and an outlet. An opening is formed at the longitudinal end of a gas-conducting channel connected to the gas inlet the end facing away from the gas inlet, and a throttle aperture movably mounted in the longitudinal direction of the gas conducting channel. The gas conducting channel and an outlet channel form an annular gap through which crankcase ventilation gases flow via a nozzle gap, and the housing has an additional opening to which a reference pressure can be applied on the throttle aperture side facing away from the gas conducting channel. The throttle aperture extends radially beyond the annular gap and has a seal region molded onto the edge that is sealingly arranged in a recess formed in the housing such that the throttle aperture fluidically separates the additional opening from the gas inlet.

The invention relates to a cylinder head cover for an internal combustion engine which has, in addition to the mere covering function, additional integrated functions, wherein the cylinder head cover according to the invention includes the following: a cover body, which, when the cylinder head cover is assembled, is mounted on an engine block of the internal combustion engine and covers a cylinder head of the internal combustion engine; a separator, through which a raw gas stream can be conducted for the purpose of cleaning, the separator being at least partially formed and/or delimited by the cover body; and/or a valve device, which is at least partially formed and/or delimited by the cover body; wherein the cylinder head cover includes a nozzle device which is integrated in the separator and/or the valve device.

A blow-by gas treatment device causes blow-by gas in a space defined by a cylinder head and a head cover in an internal combustion engine to flow back into an intake pipe. The blow-by gas treatment device includes a pipe joint and a blow-by gas pipe connected to the intake pipe. The pipe joint includes a basal end connected to the head cover, a distal end, a sensor-connected part connected to the pressure sensor, and a constriction located closer to the basal end than the sensor-connected part. The blow-by gas pipe is connected to a position of the pipe joint closer to the distal end than the sensor-connected part.

The invention relates to an internal combustion engine, comprising an intake path, a crankcase, an exhaust gas path and a crankcase ventilation means, wherein the crankcase ventilation means is open, closed or separate. The internal combustion engine according to the invention comprises an intake path, a crankcase, an exhaust gas path and an open crankcase ventilation means, wherein the open crankcase ventilation means comprises a first line and a second line, wherein the first line is designed to connect the exhaust gas path to the crankcase in order to guide exhaust gas out of the exhaust gas path to the crankcase, and wherein the second line is designed to connect the crankcase to the exhaust gas path in order to discharge exhaust gas and leakage gases located in the crankcase from the crankcase and to feed them to the exhaust gas path.