An ejector includes: a decompression chamber in an outer pipe on an air entrance side; a throat in the outer pipe on an air exit side; a nozzle in the outer pipe on the air entrance side, the nozzle having a leading end portion placed in a decompression chamber to inject air; and a suction port in the decompression chamber to suck blow-by gas into the decompression chamber. The air injected from the nozzle generates negative pressure in the decompression chamber to suck in blow-by gas through the suction port, and the sucked gas is discharged together with air through a throat. The valve in the nozzle includes a valve seat, a valve element, and a spring to press the valve element in a direction to separate from the valve seat. The valve element is formed with a bottom-closed cavity opening toward an upstream side of an air flow.

Restrictors are disclosed that include a body defining a Venturi tube having a throat defining a junction of a converging inlet cone to a diverging outlet cone along a longitudinal axis thereof, and with the converging inlet cone and the diverging outlet cone each defining an inner passageway that transitions as a hyperbolic or parabolic function toward the throat.

Methods and systems are provided for enhancing crankcase ventilation in a boosted engine. During boosted conditions, a crankcase may be ventilated via vacuum generated at an aspirator coupled in a compressor bypass passage. However, when the aspirator is plugged, pressure in the crankcase may be relieved by flowing crankcase gases through an aspirator bypass passage.

A vehicle includes a diesel engine having a crankcase and a crankcase ventilation system connected to the crankcase and configured to ventilate crankcase exhaust gases. The vehicle also includes a diesel exhaust fluid (DEF) reservoir including DEF therein, the DEF configured to reduce emissions of the diesel engine, and a DEF cooling system operably connected to the crankcase and the DEF reservoir. The DEF cooling system is configured to receive the DEF and use the DEF to cool the crankcase exhaust gases passing therethrough.

A vehicle includes a diesel engine having a crankcase and a crankcase ventilation system connected to the crankcase and configured to ventilate crankcase exhaust gases. The vehicle also includes a diesel exhaust fluid (DEF) reservoir including DEF therein, the DEF configured to reduce emissions of the diesel engine, and a DEF cooling system operably connected to the crankcase and the DEF reservoir. The DEF cooling system is configured to receive the DEF and use the DEF to cool the crankcase exhaust gases passing therethrough.