An engine unit including a heater provided in a blow-by gas returning path for returning a blow-by gas that leaks out from a combustion chamber of an engine to an intake path. The heater is electrically connected to a controller of the engine through wiring harnesses. The controller is configured to, while controlling energization of the heater, perform an abnormality detection on the wiring harness based on a magnitude of current flowing to the wiring harness during energization of the heater, and perform an abnormality detection on the heater and the wiring harnesses based on a magnitude of voltage applied to the wiring harness located downstream from the heater during non-energization of the heater.

As a further improvement of the technique of minimizing or preventing excessive cooling of an oil separator, an effective blow-by gas heating apparatus which minimizes or solves the problems due to frozen blow-by gas in an engine externally equipped with an oil separator is provided. The blow-by gas heating apparatus includes: a heat emitting structure abutted onto an oil separator configured to trap and remove oil from blow-by gas. The heat emitting structure has a heat emitting case including inside a passage for engine cooling water. The heat emitting case includes a ceiling wall being in surface-contact from below with a bottom surface of the oil separator.

The present disclosure relates to a structure for preventing freezing of moisture contents within a blow-by gas in an intake manifold, capable of preventing the blow-by gas introduced into the manifold from freezing even under a low temperature environment. The structure includes a positive crankcase ventilation (PCV) channel into which the blow-by gas is introduced, an insulating member having a first side and a second side that communicate with each other and inserted into the PCV channel, and a PCV nipple having a first end and a second end that communicate with each other and inserted into the insulating member to guide the blow-by gas. The insulating member includes an outer peripheral surface in contact with an inner peripheral surface of the PCV channel and an inner peripheral surface in contact with an outer peripheral surface of the PCV nipple to surround the peripheral surface of the PCV nipple.

A heating device for a fluid line has a heat-conductive pipe segment to be flowed through by a fluid. An electrical heating element that heats the pipe segment is provided. An electrical plug connection device is provided, wherein contact elements connect the heating element electrically to the plug connection device. A fastening element attaches the heating element and the contact elements to the pipe segment. A plastic housing encapsulates the fastening element, the heating element, and the pipe segment.

A check valve is described for a gas-carrying line in a motor vehicle, in particular for the venting of a crankcase, having a valve housing which has a valve seat, a valve disk which abuts against the valve seat in a closed position and an electric heating device for heating the valve housing, wherein the valve disk is integrally configured with a spring and fastening section that is fixed to the valve housing and generates a closing force that presses the valve disk against the valve seat, and wherein the valve housing has a metal body, which forms the valve seat and on its outside forms a thermal coupling surface, on which the electric heating device sits and which extends together with the electric heating device beyond the valve seat both in the flow direction and in the opposite direction.

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 breather device for an engine which prevents a blow-by gas outlet passage from being blocked due to freezing, is provided, which includes a valve holder in a cylinder head cover and a breather valve supported by the holder. The holder includes a holder body having a valve port of the breather valve, a metal outlet passage pipe having a blow-by gas outlet passage formed inside, the blow-by gas outlet passage communicating with the valve port and being located below the valve port, and a heater that heats the outlet passage pipe. An outer peripheral surface of the outlet passage pipe is wrapped with the holder body formed of a material having lower thermal conductivity than that of the outlet passage pipe. The holder body has a heater insertion port, and the heater is inserted from the heater insertion port toward a heat input wall of the outlet passage pipe.

A system for recirculating blow-by gases into an air intake duct of an internal combustion engine includes a separating device to separate oil in a flow of blow-by gases of the engine. The separator device has an inlet for receiving blow-by gases, at least one discharge for returning the oil separated to the engine, and an outlet for clean blow-by gases. A recirculation duct connects the outlet to an air intake duct of the engine. The recirculation duct has an end connected to the intake duct by a T-connector member, with a main duct portion arranged along the intake duct and a tubular element protruding inside the main duct portion. The tubular element protruding inside the main duct portion has an annular end surface that has an irregular profile, preferably in the form of a saw-like toothed profile.

An engine fluid heating apparatus, preventing failure in heating fluid, is provided. A control device opens a sub switch during an initial opening period (IOP) after closing a main switch, and the control device closes the sub switch during an initial closing period (ICP) after the IOP. Circuit normality is displayed by turning on an indicator lamp when a heater feeding circuit is electrically conducted via a bypass electric circuit during the IOP. Heater feeding is displayed by turning off the indicator lamp when power is supplied to the electric heater via a trunk electric circuit during the ICP. Circuit abnormality is displayed by turning off the indicator lamp when the heater feeding circuit is not electrically conducted via the bypass electric circuit during the IOP, and the circuit abnormality display is held by keeping the indicator lamp off during the ICP immediately after the IOP.

A check valve is described for a gas-carrying line in a motor vehicle, in particular for the venting of a crankcase, having a valve housing which has a valve seat, a valve disk which abuts against the valve seat in a closed position and an electric heating device for heating the valve housing, wherein the valve disk is integrally configured with a spring and fastening section that is fixed to the valve housing and generates a closing force that presses the valve disk against the valve seat, and wherein the valve housing has a metal body, which forms the valve seat and on its outside forms a thermal coupling surface, on which the electric heating device sits and which extends together with the electric heating device beyond the valve seat both in the flow direction and in the opposite direction.