Abstract: A combustion engine is configured to substantially reduced pressure in the crankcase relative to atmospheric conditions. Under the conditions of reduced pressure, removal of contaminants present in the lubricating oil present is effected, which may provide one or more benefits including extended service intervals, reduced volumes of motor oils used, and lessened wear of internal engine components.

Abstract: An internal combustion engine that includes a crankcase having a crankcase pressure defined within the crankcase relative to an ambient pressure. The crankcase pressure varies in response to operation of the internal combustion engine. A crankcase pressure regulator is in fluid communication with the crankcase, and the crankcase pressure regulator includes a first passageway defining a first flow path, a second passageway defining a second flow path in a parallel arrangement to the first passageway. When the crankcase pressure is less than a first predetermined pressure, the first valve moves to the open position to allow a fluid flow into the crankcase through the first passageway. When the crankcase pressure is greater than a second predetermined pressure, the second valve moves from the closed position to the open position to allow a fluid flow from the crankcase through the second passageway.

Abstract: The present invention provides a crankcase ventilation system and resonator for a turbocharged internal combustion engine assembly. The resonator, designed for intake noise reduction, is mounted to the engine. An oil separation unit, designed for passage of blowby gases, is mounted to a cam cover, sandwiched between the resonator and cam cover. The resonator has a resonator body defining a resonator volume therein. The resonator fluidly communicates the oil separation unit with the turbocharger air inlet pipe, whereby blowby gases are evacuated from the cam cover and delivered through the resonator volume for reintroduction to the engine's air intake system. Integration of the blowby passages into the resonator reduces the number of potential leak paths in the air induction system, and reduces overall engine mass, cost, and packaging size. The present design also offers improved On-board Diagnostics (OBD) by allowing only large flow areas to be disconnected.

Abstract: An assembly for cleaning blowby gases has an electric heater and a downstream catalyst positioned in series relationship in a blowby conduit leading from an engine's crankcase to the atmosphere. The heater is controlled by a controller to maintain a selected temperature at the inlet to the catalyst as determined by a temperature sensor. The heating of the blowby gases increases the blowby gas temperature to a level where the catalyst is active to oxidize the constituents of the blowby gas stream.

Abstract: The invention concerns a device for separating fluid particles from a gas flow, in particular from a crankcase gas flow of an internal combustion engine. A valve is provided to allow a distribution of the gas flow to at least two cyclones depending on the volumetric flow. The valve consists of a cylinder through which the gas can flow. Inside the cylinder is a piston. This piston is designed inside the cylinder with a clearance fit or provided with one or several boreholes. In case of a low gas flow and because of the tolerances or boreholes, this gas flow will be directed around the cylinder to a first cyclone. When exceeding a certain volumetric flow the piston moves inside the cylinder and opens at least one more cyclone for the gas flow to flow through.

Abstract: A fuel feed system of an engine is provided with a gas-fuel separating unit for separating oil mist generated in an engine case from air with a labyrinth, and an auto fuel cock is operated by pressure pulsation of the air from which the oil mist is separated by the gas-liquid separating unit. Thus, infiltration of the oil mist into the auto fuel cock is suppressed to the minimum, and a malfunction of the auto fuel cock caused by accumulation of the oil can be prevented. Additionally, a breather passage for feeding the air, from which the oil mist is separated by the gas-liquid separating unit, to a breathing unit is connected the auto fuel cock via a negative pressure tube. Thus, it is unnecessary to provide a specific passage for transmitting the pressure pulsation of the air in the engine case to the auto fuel cock.

Abstract: Arrangements for use in crankcase ventilation are described and shown. Included are serviceable crankcase ventilation filter cartridges which include a media pack axial drain arrangement, for preferred, efficient, operation. A crankcase ventilation filter arrangements including a housing and such a serviceable cartridge is shown. Also shown and described are methods of assembly, operation and use.

Abstract: The present invention relates to a device for venting a crank space in an internal combustion engine (1) having a suction device (5) for sucking out blow-by gases from the crank space (3) and having a venting line (4) which leads from the crank space (3) to the suction device (5) and in the course of which a throttle device (6) or a pressure regulating element (7) is arranged in order to bound a partial pressure which is generated by the suction device (5) in the crank space (3). It is essential to the invention here that an oil mist separator (8) which is embodied as an impactor is integrated into the throttle device (6) or into the pressure regulating element (7).

Abstract: The present invention relates to a deaerating and aerating device (19) for an internal combustion engine (1) for discharging blowby gas out of a crankcase (3), comprising a first line (20) which is connected at one end to the crankcase (3) and at the other end to a fresh gas line (7) downstream of a supercharging device (10) and which contains a deaerating valve (23), and a second line (21) which is connected at one end to the fresh gas line (7) upstream of the supercharging device (10) and at the other end to the crankcase (3) and which contains a throttle device (28) and, parallel thereto, a non-return check valve (29) which provides a blocking action in the direction of the crankcase (3).

Abstract: The invention relates to a ventilation device (19) for an internal combustion engine (1) for evacuating blow-by gas from a crankcase (3), comprising a first line (20), which is connected at the one end to the crankcase (3) and at the other end, downstream of a forced induction device (10), to a fresh-gas line (7) and contains a ventilation valve (23), and a second line (21), which is connected at the one end, upstream of the forced induction device (10), to the fresh-gas line (7) and at the other end, between the crankcase (3) and the ventilation valve (23), to the first line (20) and contains a throttle device (23).

Abstract: The invention relates to a crankcase breathing system (1) for an internal combustion engine, comprising at least one oil separating apparatus with a preliminary separator (3) and a main separator (4) arranged downstream of the same, with the preliminary separator (3) comprising a diffuser (11) between an inlet (7) and an outlet (8) which expands in the direction of flow. In order to achieve high separation rates in the simplest possible way it is provided that the preliminary separator (3) is arranged integrally with the main separator (4), with preferably the preliminary separator (3) and the main separator (4) forming a separator unit (2).

Abstract: Disclosed herein is a breather assembly for use in an internal combustion engine and a method of operating an internal combustion engine. In at least one embodiment, the breather assembly includes an input chamber for receiving blow-by gas, the input chamber bounded at least partially by a crankcase exterior, and a standpipe situated inside the input chamber for directing blow-by gas into the input chamber. Additionally, the breather assembly can include an input drainback passage situated inside the input chamber and an output chamber situated adjacent the input chamber, the chamber having an inner wall with a one-way valve that allows blow-by gas to flow from the input chamber to the output chamber. The breather assembly can also include an output drainback aperture situated in the inner wall and an output chamber housing that substantially encloses the output chamber and includes an exhaust port for exhausting blow-by gas.

Abstract: The present invention includes an air introduction device capable of introducing air into a crankcase of the engine during a supercharging operation of a supercharger, so that blow-by gas within the crankcase can be scavenged into the intake air passage.

Abstract: The present disclosure relates to a closed crankcase emission control system that includes an engine. The closed crankcase emission control system also includes a turbo disposed upstream from the engine that is in fluid communication with the engine. The closed crankcase emission control system further includes an air filter disposed upstream from the turbo that is in fluid communication with the turbo. Additionally, the closed crankcase emission control system includes a blow-by filter arrangement disposed downstream of the engine and upstream from the turbo. The blow-by filter arrangement is adapted for filtering blow-by gases from the engine. Furthermore, the closed crankcase emission control system has a diameter restriction disposed between the turbo and the air filter that is in fluid communication with the air filter, the turbo, and the blow-by filter. The turbo draws air from the air filter and a filtered gaseous stream from the blow-by filter arrangement through the diameter restriction.

Abstract: There is provided a material activating device capable of being formed in any one of various shapes and having an improved material activating effect. A material activating device formed by superposing a plurality of polymer film 31 each having one surface coated with a metal film 32, and radioactive layer 33 of a radioactive means has a very small thickness and is very flexible. The metal films 32 are insulated from each other by the electrically insulating polymer films 31 and are spaced from each other by a distance corresponding to the thickness of the polymer films 31. Consequently, the material activating effect of the radioactive rays emitted by the radioactive layer 33 of the radioactive means is enhanced.

Abstract: A separation assembly is generally described that can chemically treat condensate material in a fluid stream. One particular example of a separation assembly is a crankcase filtration assembly used in engine oil filtration and that includes an additive material disposed within the crankcase filtration assembly. The additive material chemically treats condensate material of blow-by fluids received by the crankcase filtration assembly when a condition is present in the condensate material. For example, the crankcase filtration assembly provides a unique structure with a chemically treated component that can reduce an acidic condition in condensate material received by the crankcase filtration assembly, and even more generally may extend engine oil life.

Abstract: An engine assembly may include an engine block, a first cylinder head, and an air intake assembly. The engine block may include a first bank defining a first set of cylinders. The first cylinder head may be fixed to the first bank and may include a first set of intake ports. The air intake assembly may include an intake air tube, a crankcase ventilation housing integrally formed with the intake air tube, and an oil separation assembly located within the crankcase ventilation housing. The intake air tube may be in communication with the first set of intake ports and an air source. The crankcase ventilation housing may have a wall at least partially defined by the intake air tube.

Abstract: The invention relates to a cylinder head (1) of an internal combustion engine, comprising at least one hollow camshaft (2) which forms an exhaust for blow-by gases containing oil mist from the crank housing and is also embodied as an oil mist pre fractionator for the preliminary separation of the oil part from these gases. Furthermore, an oil mist post-fractionator (5) is axially arranged on the end of the camshaft (2), in order to carry out an especially effective separation of oil dissolved in the blow-by gases.

Abstract: Device for cleaning crankcase gases from an internal combustion engine by means of a centrifugal separator (14), comprising a housing (16) with a rotor (22), which is rotatably supported in the housing and has a plurality of tightly separated separating discs (20). The housing (16) has an interface surface, which is designed for direct mounting of the housing (16) over a corresponding opening in a valve cover of the internal combustion engine.

Abstract: An oil return passage that is open at its upper end to a cam chamber and is open at its lower end to a crank chamber is formed to extend from a cylinder head to a cylinder block. A heat exchanger having a double-pipe structure is housed in the oil return passage. Lubricating oil fed from the cam chamber is passed through an oil-collection outer passage of the heat exchanger, and separated oil fed from a separator case of a PCV system is passed through an oil-collection inner passage of the heat exchanger, so that heat of the lubricating oil is imparted to the separated oil. Thus, water contained in the separated oil is evaporated, and the amount of water flowing into an oil pan can be reduced.

Abstract: A total amount of engine oil carried from a crankcase into an intake passage by blow-by gas from the start of the use of the internal combustion engine or the engine oil is calculated. It is determined whether the total oil carried amount is greater or less than an optimum value every predetermined operation period of the internal combustion engine. Then, when it is determined that the total oil carried amount is greater than the optimum value, the gas flow rate of the blow-by gas controlled based on the engine operation state is reduced until next determination process is performed. When it is determined that the total oil carried amount is less than the optimum value, the gas flow rate is increased until next determination process is performed.

Abstract: To provide an oil separator including multiple cones and having a simple structure and high trapping efficiency for oil mist. An oil separator can include multiple cones arranged in a line and a chamber for blow-by gas, which is formed in adjacent to the line of the cones, and arranged at an upper side surface of the cones, the chamber being provided with a flow-in port at a position in front of the line of the cones, in which upper outer peripheral walls of the cones at portions facing the chamber constitute partition walls provided with slits, which constitute inlets for the blow-by gas to enter the cones.

Abstract: An electromagnetic PCV valve includes a valve seat, a valve element, a step motor for moving the valve element, and a housing that houses the valve seat, the valve element, and the step motor. When the valve element is moved by the step motor, a size (an opening degree) of a blow-by gas passage defined between the valve seat and the valve element is changed. The step motor is configured to selectively receive energization for moving the valve element and energization for holding the valve element in a fixed position. A heating apparatus of the PCV valve 1 includes a cover member and an output shaft that conducts heat generated in the step motor by energization to the valve element and the valve seat, and an electronic control unit (ECU) for conducting energization of the step motor to hold the valve element in the fixed position.

Abstract: The invention relates to a blow-by gas recirculation system for an internal combustion engine. An oil separation cover 10 has a surge-tank mounting portion 400 integrally formed therewith in a columnar shape having a cam-shaped cross-section and a height approximately equal to that of an oil separation space OS. The surge-tank mounting portion 400 has a flat upper surface serving as a mounting seat surface 401 capable of coming into surface contact with an attaching seat surface 7a of a surge tank 7. A first opening 403 of a gas passage from a chamber 300 is opened in a vicinity of an opening of a support through-hole 402 on the mounting seat surface 401.

Abstract: This document describes a device for cleaning of crankcase gases from a combustion engine, and a combustion engine having such a device. An inlet conduit is connected to a crankcase of the combustion engine. A centrifugal separator receives a flow of crankcase gases from the crankcase via the inlet conduit and comprises a routable centrifuge rotor for centrifuging the crankcase gases. A drive device drives the centrifuge rotor. An outlet conduit discharges cleaned crankcase gases from the centrifugal separator. The rotary speed of the drive device, and thus the rotary speed of the centrifuge rotor, is controllable depending on the gas pressure in the crankcase. An export conduit may be connected to the inlet conduit and adapted to enable discharge of a flow of crankcase gases from the crankcase by-passing the centrifugal separator depending on the gas pressure in the crankcase.

Abstract: A dry sump oil tank assembly for a vehicle is provided with a housing defining an internal cavity. The housing is configured with a laterally-extending portion to add lateral volume to the internal cavity and has at least one internal baffle attached to the housing within the internal cavity below the laterally-extending portion and configured to reduce sloshing of oil within the cavity. The dry sump oil tank assembly is particularly useful for high performance applications, such as racing vehicles, and may utilize components from standard vehicle applications, thus maximizing the economies of scale of producing such components and being suited for a vehicle that may be typically used in standard driving conditions, but occasionally subjected to high performance use.

Abstract: A blow-by gas recirculation structure for an engine includes a gas-liquid separating member, a cylinder head, a support member and a mounting bolt. The gas-liquid separating member includes a gas-liquid separating passage to separate oil from the blow-by gas. The cylinder head includes a communication passage communicating with the air intake system. The support member is configured and arranged to rotatably support a camshaft in the cylinder head. The mounting bolt securely fastens the support member to the cylinder head with the mounting bolt threadedly engaging within the communication passage of the cylinder head. The mounting bolt has an axial through hole axially extending there-through and communicating with the gas-liquid separating passage so that the blow-by gas that has passed through the gas-liquid separating passage is recirculated from the axial through hole of the mounting bolt, through the communication passage, and into the air intake system.

Abstract: A device for eliminating oil particles from the crankcase ventilation gas of an internal combustion engine. The device is located in the flow duct of the gas that runs from the crankcase to an induction tract of the engine. The device includes an oil separator in the form of an outlet for the gas with a deflection of the flow, causing the oil particles to be deposited on a baffle surface and thus to be eliminated from the crankcase ventilation gas flow. The device has an infeed cross-section, which lies upstream of the baffle surface when viewed from the flow direction of the crankcase ventilation gas, and which is sub-divided into several infeed sub-sections. The baffle surface is a solid surface that is devoid of perforations. The baffle surface is configured on a valve body, which lies downstream of the infeed sub-sections when viewed in the flow direction of the gas, and which is pre-tensioned by a force.

Abstract: Crankcase venting system comprising an oil separator arranged in a housing that separates the housing into an unfiltered air side and a filtered air side, wherein in the area of the unfiltered air side a valve is arranged that is comprised of a valve plate, a pressure spring resting against the valve plate, as well as a valve seat that is closed or opened by means of the valve plate, and wherein the valve is closed off by a lid that is locked or snapped in place.

Abstract: A CCV apparatus that exhausts blow-by gas from a crankcase effectively and thereby prevents pressure in a crankcase from excessively increasing may include: a lower case, a middle case comprising a body, an upper plate and a cup wherein the upper plate is provided with a blow-by gas passageway coupled with a filter in the cup for flowing blow-by gas into the body therethrough and at least a gas hole formed in the upper plate outside the cup for flowing the filtered blow-by gas in the body to the exterior of the cup, and an upper case enclosing an opening at an upper end of the cup. The apparatus further comprises a by-pass passageway selectively detouring the blow-by gas from the inlet pipe according to a pressure of the blow-by gas in the inlet pipe wherein the by-pass passageway is mounted at the exterior of the cases.

Abstract: A crank-case ventilation filter set. A crankcase ventilation filter filters oil from blow-by gas. An inlet pipe transports the blow-by gas from an engine to the filter. An outlet pipe transports the blow-by gas from the filter to an intake device. An oil return pipe transports oil, such as by gravity, from the filter to an oil pan provided at a lower portion of the engine. A valve for preventing back-flow of oil is provided in the oil return pipe. The valve is disposed in the oil pan above an oil top limit line of the oil pan.

Abstract: A vapor purifier for oil recovery from and cleansing of deleterious matter carried by oil vapors in a crankcase of an internal combustion-type engine generally includes a coil member that can separate the oil from the vapors by passing the vapors over and/or through the coil member. As the vapors impinge upon the surface(s) of the coil member, oil in the blow-by vapors condenses thereon. The vapor purifier can include a flow equalization member to maintain a normal engine intake manifold pressure for driving modes of the engine. As a result, the vapor purifier of the present invention can maintain the air to fuel stoichiometric ratio of the engine system. Additional components, such as filters and/or disks can also be included in the vapor purifier to promote oil recovery and cleansing of deleterious matter from the vapors, which act as a host for the deleterious matter.

Abstract: An internal combustion engine cover includes a peripheral rail for attaching a cover to an engine component and an enclosure portion formed integrally with a peripheral rail. At least one port formed in the enclosure portion holds an electronic module which is mounted through the port and which may include an oil separator as well as an electronic device.

Abstract: A two stage drainage gas-liquid separator assembly includes an inertial gas-liquid impactor separator having one or more nozzles accelerating a gas-liquid stream therethrough, and an inertial impactor in the path of the accelerated gas-liquid stream and causing liquid particle separation from the gas-liquid stream, and further includes a coalescer filter downstream of the inertial gas-liquid impactor separator and effecting further liquid particle separation, and coalescing separated liquid particles.

Abstract: The present invention provides a breather apparatus in a combustion engine having a sufficient gas-liquid separation function without involving an additional parts such as a breather tank and an arrangement space thereof. A breather chamber is formed in an air cleaner case, and the breather chamber is communicated with a crank case through a breather pipe. Preferably another breather chamber is formed in the crank case in addition to the breather chamber in the air cleaner case, and the breather pipe is connected to a breather outlet of the breather chamber in the crank case. The breather chamber in the air cleaner case is provided in a clean side space on an intake-air downstream side of a filter element.

Abstract: A blowby gas returning device is arranged to allow blowby gas leaking from a combustion chamber of an engine to flow in an intake passage through a returning passage and return to the combustion chamber, and arranged to regulate a flow rate of the blowby gas by a PCV valve provided in the returning passage. This blowby gas returning device comprises an outside-air passage for mixing outside air into the blowby gas before being introduced into the PCV valve; and an open-close valve for opening and closing the outside-air passage. An electronic control unit controls the open-close valve to open when the operating state detected by sensors is an idle state.

Abstract: A breather device disposed in a timing-gear chamber of an engine includes an oil separator rotatable with a camshaft, and a tubular breather housing that removes the oil mist by working in cooperation with the oil separator. The oil separator has a plurality of fins arranged annularly around an axis line of the camshaft at fixed intervals. The tubular breather housing has openings in a periphery wall thereof and surrounds the oil separator.

Abstract: A device and method for heating a positive crankcase ventilation system in a hybrid vehicle includes a ventilation device, provided on a crankcase, and a supercooling cycle for cooling power electronics for an electric motor of the hybrid vehicle. The ventilation device is heatable by way of the supercooling cycle in order to prevent icing of the ventilation device.

Abstract: An internal combustion engine including a valve system and a breather system. The valve system includes a camshaft having intake cams and exhaust cams. The intake cams open and close intake valves, and the exhaust cams open and close exhaust valves. The breather system includes an upstream-side breather chamber and a downstream-side breather chamber. Blow-by gas flows into the upstream-side breather chamber through a chain chamber. The down-stream side breather chamber is provided in the camshaft, and also formed of a through hole constituted of a plurality of hole portions. The hole portions have different sizes and are aligned in the axial direction. The through bole opens to the chain chamber at a first shaft end portion of the camshaft, and also opens to the down-stream side breather chamber at a second shaft end portion of the camshaft. The down-stream side breather chamber is formed of a cam holder.

Abstract: A separator for separating liquids in a fluid stream generated by blow-by gases produced in a crankcase of an internal combustion engine wherein the fluid stream includes both gasses and liquids. The separator including an inlet in fluid connection with the engine for receiving the fluid stream and an outlet in fluid connection with the engine to return a gas stream to the engine. The separator further including a fluid path fluidly connecting the inlet to the outlet and a containment vessel in fluid connection with the fluid path. The separator having a fluid stream accelerator in the fluid path and the accelerator accelerating the fluid stream to at least partially separate the gasses from the liquids in the fluid stream.

Abstract: The invention relates to an oil separator for the separation of oil from the crankcase ventilation gas of an internal combustion engine, comprising a housing wherein a separating element is arranged, comprising an inlet for gas to be cleaned, an outlet for cleaned gas and an outlet for separated oil. The novel oil separator is characterized by a crude gas area of the housing adjacent to the inlet and provided with an oil sink wherein coarse oil carried by the incoming gas flow is deposited; also characterized in that the oil separator comprises, in addition to the separating element, a coarse oil cyclone whose inflow opening is located at the same level as the oil sink therein, and in that the separating element has an inflow opening which is spatially located above the inflow opening of the coarse oil cyclone.

Abstract: The present invention provides a breather apparatus in a combustion engine having a sufficient gas-liquid separation function without involving an additional parts such as a breather tank and an arrangement space thereof. A breather chamber is formed in an air cleaner case, and the breather chamber is communicated with a crank case through a breather pipe. Preferably another breather chamber is formed in the crank case in addition to the breather chamber in the air cleaner case, and the breather pipe is connected to a breather outlet of the breather chamber in the crank case. The breather chamber in the air cleaner case is provided in a clean side space on an intake-air downstream side of a filter element.

Abstract: A device for separation of oil from the hot gases (5) that are ventilated out from the crank house of a combustion engine. The separation is accomplished by contacting th gases with a cold wall (2) where the oil deposits and is then drained away. The wall (2 is kept cold by the cold gases (4) leaving the device which makes the cooling demand small. The leaving gases (4) are heated by this, so that a higher degree of separation f purification can be accomplished by the use of several similar steps in series.

Abstract: Embodiments of the present invention relate to a heating device for a fluid line, in particular for a crankcase venting system in an internal combustion engine, with a heating element and with a holding device, through which the heating element can be mounted on the fluid line. Embodiments of the invention also relate to a fluid line for the accommodation of the said heating device and to a heating module with a fluid line and a heating device fitted to it. Embodiments of the invention also relate to a method for the manufacture of the heating device mentioned above.

Abstract: A head cover assembly for covering a crankcase of an internal combustion engine includes a head cover and an integral oil separator. The oil separator includes a housing that defines a flow path that separates oil from crankcase gases passing therethrough. At least a portion of the housing is integrally formed along an inner surface of the head cover.

Abstract: In a centrifugal oil separator in an internal combustion engine including a centrifuge housing which is placed in a rotationally fixed manner onto a rotating centrifuge shaft, the centrifuge housing is manufactured from plastic and a metal bushing is integrated into the centrifuge housing and is slipped onto the centrifuge shaft.

Abstract: The present invention relates to a combustion engine, comprising an intake system having a throttle valve controlling an air flow to the combustion engine, a brake booster being in fluid communication with the intake system, downstream the throttle valve, via an evacuation duct for evacuation of air from the brake booster to the intake system, a crankcase being in fluid communication with the intake system, downstream the throttle valve, via a low load duct for conducting crankcase gases to the intake system, a venturi tube forming part of the low load duct, wherein the venturi tube comprises a narrow venturi tube portion forming a flow resistance within the low load duct through which the crankcase gases have to pass, wherein the evacuation duct is also fluidly connected to the venturi tube portion, via a connection duct, for further evacuation of air from the brake booster to the intake system.

Abstract: An oil separator for use in a vehicle air system includes a recycling valve for removing coalesced oil. The recycling valve may include a piston movable in a cylinder in response to a control air pressure to open the recycling valve and thus drain coalesced oil from a sump under the influence of residual air pressure in the sump. The separator may include a fixture for mounting the separator to a vehicle, including a plurality of ports extending from an inlet port for directing air into the cartridge with a combined flow area at least equal to the flow area of the inlet port. The plurality of ports preferably extend at a right angle to the direction of flow of air through the inlet port. A safety relief valve on the separator releases air when the pressure exceeds a predetermined pressure.

Abstract: In an intake valve lift variable engine including: an engine body; a cylinder head; an intake valve which is disposed in the cylinder head and which is controlled to be open and close so as to regulate the amount of intake air; and an intake system having no throttle valve and connected to the cylinder head, blow-by gas is sucked from a crank case of the engine body into a first pump and pressurizingly transferred by the first pump to the side of the intake system, and purge gas from a canister is mixed into the blow-by gas pressurizingly transferred by the first pump. Thus, the blow-by gas and the purge gas are guided to the intake system.

Abstract: A breather chamber is located in a blow-by gas passage to separate oil from blow-by gas. A partitioning member partitions the interior of the breather chamber into a plurality of spaces. The partitioning member is arranged such that the spaces extend along the flowing direction of the blow-by gas and that an adjacent pair of the spaces are connected at ends in the flowing direction. A separating member is provided in at least one of the spaces. The separating member obstructs the flow of the blow-by gas in the associated space, thereby separating oil from the blow-by gas. Therefore, oil is separated from the blow-by gas securely and is prevented from being brought out of the breather chamber.