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.

A blow-by gas treating device has an oil separator. A tubular attachment portion is disposed at a discharge port of the oil separator. A PCV valve is inserted in the attachment portion. The PCV valve includes an inflow hole, a discharge hole, a flow rate regulating portion, and a stopping portion. The stopping portion is located closer to the inflow hole than to the flow rate regulating portion. The stopping portion has a dimension greater than the inner diameter of the attachment portion in a direction perpendicular to the central axis of the attachment portion. The flow rate regulating portion is surrounded by the attachment portion. The stopping portion is arranged in the space defined by the oil separator.

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.

A cylinder head cover includes a main body and a side projection portion. The main body is provided so as to cover a cylinder head, and collects a blowby gas. The side projection portion discharges the blowby gas toward an intake passage. The cylinder head cover includes a cover gas passage through which the blowby gas flows from a main body gas passage to an outlet of the side projection portion. A minimum passage cross-sectional area portion of the cover gas passage is provided not in the side projection portion but in the main body gas passage. The main body has a hole or a projection branch passage at a position of the main body gas passage that is downstream of the minimum passage cross-sectional area portion. The main body, the side projection portion, and the hole or the projection branch passage are integrally molded.

A positive crankcase ventilation (PCV) system for an internal combustion engine having an air induction system configured to supply air to the includes a PCV line configured to fluidly couple between a crankcase of the engine and the air induction system, a condenser disposed on the PCV line and configured to condense water vapor and fuel vapor contained in blow-by gases received from the crankcase to separate the water vapor and fuel vapor from the blow-by gases and form a water/fuel mixture and a lean blow-by gas, and an oil separator disposed on the PCV line and configured to receive the lean blow-by gas from the condenser and separate oil therefrom to form a filtered blow-by gas for return to the air induction system.

A turbocharger is provided and includes a compressor housing and a recirculation slit and a recirculation passage provided at an inlet of the compressor housing to enable air flowing into the compressor to be recirculated. A gas supply part supplies blow-by gas towards the inlet of the compressor housing to allow blow-by gas to be joined with air recirculated through the recirculation slit and the recirculation passage and to guide recirculating air towards a compressor wheel.

This heat exchanger is provided with an inner tube 2, a first flow passage 3 formed inside the inner tube 2, an outer tube 4 disposed coaxially with the inner tube 2 on the radially outer side thereof, a second flow passage 5 formed between the inner tube 2 and the outer tube 4, annular separating walls P1 to P4 which divide the second flow passage 5 into a plurality of spaces S1 to S5 in the axial direction of the outer tube 4, and space outlets E formed in one location in the circumferential direction of each separating wall P1 to P4, wherein the spaces S1 to S5 are configured to cause a second fluid to swirl about second axes Y perpendicular to a first axis X positioned at the center of the outer tube 4.

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 engine includes: an exhaust manifold 7 close to one of left and right side surfaces of an engine; a turbocharger 60 having an exhaust-side inlet connected to the exhaust manifold 7; and a rocker-arm-chamber-integrated intake manifold 8 being disposed on an upper surface of a cylinder head 5 and integrally including a rocker arm chamber 90 and an intake manifold 6. The intake manifold 8 has a wall 101 dividing the rocker arm chamber 90 close to the one of the left and right side surfaces of the engine 1 and the intake manifold 6 close to the other of the left and right side surfaces to isolate the rocker arm chamber 90 and the intake manifold 6 from each other. The rocker arm chamber 90 has, in its upper portion, a positive crankcase ventilation device 69 protruding therefrom and being configured to return blowby gas to an intake system. The positive crankcase ventilation device 69 has, in its side surface, a blowby-gas discharge port 67 connected with a gas conduit 68 through which blowby gas is delivered to an intake-side inlet of the turbocharger 60.

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.