Abstract: A seal assembly includes an outer member and an annular seal. The outer member includes an outer wall and a landing. The outer wall has a cylindrically shaped inner surface disposed about an axis and configured to oppose an outer cylindrical surface of a port. The landing extends radially inward from the inner surface of the outer wall. The annular seal member is disposed about the axis and has an inner cylindrical surface, a bottom axial surface, an outer cylindrical surface, and a circumferential groove. The inner cylindrical surface of the seal member is configured seal with the outer cylindrical surface of the port. The circumferential groove is open at the outer cylindrical surface of the seal member and extends radially inward. The landing extends into the circumferential groove and is in sealing contact with the circumferential groove.

Abstract: A method and apparatus for providing constant fresh air ventilation to the engine crankcase are disclosed. The apparatus is adapted for use with an internal combustion engine having a crankcase, an intake manifold and an air input attached to the manifold. The system includes an integrated vacuum actuator connected to the intake manifold, an actuator duct positioned between the vacuum actuator and the air input, an air-from-oil separator associated with the crankcase, a separator duct and separator control valve positioned between the separator and the intake manifold, and a bypass duct and bypass control valve between the separator duct and the actuator duct. The air input comprises an initial intake pipe and an intermediate intake pipe with the intermediate intake pipe being positioned between the initial intake pipe and the intake manifold. A fresh air control pipe and regulator assembly are attached to the intermediate intake pipe.

Abstract: A system for an engine is provided, the system comprising a vacuum pump at least partially deposed within an engine crankcase, and a fuel vapor canister coupled to an exhaust conduit of the vacuum pump via a one-way valve. By coupling the vacuum pump exhaust to the fuel vapor canister, unmetered fuel vapor flow to the engine intake may be reduced, thus decreasing engine stall events. Further, crankcase pressure may more accurately represent airflow through the crankcase via a crankcase ventilation system, thereby improving the accuracy of crankcase ventilation diagnostics.

Abstract: An engine (E) of a saddle-riding type vehicle has an engine case that is substantially L-shaped by a cylinder block (42) being protruded upward from an upper face of a front portion of a crank case (40). An air cleaner (55) is disposed rearwardly of the cylinder block (42) and above the crank case (40). An outlet (72) through which blow-by gas (G) in the engine (E) is discharged is formed in the rear portion of the cylinder block (42). A case body (84) of the air cleaner (55) has a blow-by gas introduction port (86) through which the blow-by gas (G) is introduced into the air cleaner (55). The outlet (72) of the cylinder block (42) and the blow-by gas introduction port (86) of the case body (84) are connected by a connecting pipe (90). The blow-by gas introduction port (86) is disposed close to the cylinder block (42).

Abstract: An oil passage of an internal combustion engine including a crankcase, a cylinder block integrally connected to the crankcase, a piston operatively mounted within the cylinder block, a piston jet for providing oil to the piston within the cylinder block and a breather device integrally formed on the cylinder block wherein the breather device is in communication with the inside of the crankcase. An elevation of temperature of the oil which flows in an oil supply path is prevented thus allowing oil in the oil supply path to maintain a low temperature wherein the oil in the supply path is supplied to a piston jet formed on the internal combustion engine. An oil supply path through which oil is supplied to the piston jet is integrally formed on a wall body exposed to ambient air on a peripheral wall which forms the breather device.

Abstract: An oil separator is provided with a housing having an inlet for air, and an expansion chamber located inside the housing. The oil separator introduces air containing oil that has passed through the inlet into the housing, and separates and recovers the oil from the introduced air. The transverse cross-sectional area of the expansion chamber is larger than the opening area of the inlet. The oil separator is further provided with a collected liquid storage portion that is located below the expansion chamber and collects the separated oil, a liquid communication portion having a communication hole that connects the expansion chamber to the collected liquid storage portion, and a mounting and dismounting mechanism for mounting and dismounting the collected liquid storage portion to and from the housing.

Abstract: A system for providing air to an internal combustion engine is described. The system includes a crankcase ventilation unit that separates oil from the unrefined blowby gas and discharges refined blowby gas. A conduit delivers the refined blowby gas to an air cleaner housing. The air cleaner housing includes a first chamber that receives intake air through a first port, a second chamber that receives intake air from the first chamber and refined blowby gas from the conduit through a second port, and a third chamber that receives a mixture of intake air and refined blowby gas from the second chamber and discharges the mixture through a third port. A primary filter element filters the intake air as it passes from the first chamber to the second chamber. A secondary filter element filters the mixture as it passes from the second chamber to the third chamber.

Abstract: Problem In an air intake structure for an internal combustion engine 1 where a compressor impeller 22 of a turbocharger 20 is disposed in an air intake passage (4) of the internal combustion engine 1, not to prevent an ice clump 15 from appearing on an inner wall surface of the air intake passage (4), but prevents this ice clump 15 from colliding with the compressor impeller 22, especially, a vane 22a of the compressor impeller 22 when the ice clump 15 formed on the inner wall surface of the air intake passage (4) peels off. Solution A capture member 30 is provided upstream side with respect to the compressor impeller 22 in the air intake passage (4). The capture member 30 is configured to capture an ice clump 15 formed at an inner wall surface of the air intake passage (4) when the ice clump 15 peels off.

Abstract: A separation device for separating contaminates from a gas flow may include a raw chamber receiving a contaminated gas and a clean chamber out of which a treated gas exits. A dividing wall may separate the raw chamber from the clean chamber. The dividing wall may include a perforated region defining a plurality of passage openings. The gas flow may be communicated from the raw chamber to the clean chamber via the plurality of passage openings. A gas-permeable separation structure may be arranged on a wall outlet side of the dividing wall facing the clean chamber. The separation structure may separate contaminates from the gas flow when subjected to a through flow.

Abstract: An engine includes an oil pan used for storing lubricating oil, a crankcase, a cam box, a rocker, and a distribution chamber used for separating oil & gas mixture into oil mist and liquid oil. A lubricating system comprises: the oil pan and the crankcase are communicated through an oil supply passage, and a one-way valve is disposed in the oil supply passage; the crankcase and the distribution chamber are communicated through a first oil conveying passage, and a one-way valve is disposed in the first oil conveying passage; the distribution chamber and the cam box are communicated through a second oil conveying passage; the cam box and the rocker chamber are communicated through a third oil conveying passage; the rocker chamber and the crankcase are communicated through at least one oil return passage, and a one-way valve is disposed in the oil return passage.

Abstract: Systems and methods for ventilating crankcase gases in a crankcase ventilation system via crankcase pressure pulsations are disclosed. In one example approach, a method comprises driving flow of crankcase ventilation gases through a crankcase of the engine from a fresh air inlet of the crankcase to an outlet of the crankcase via crankcase pressure pulsations while restricting backflow of crankcase ventilation gases from the outlet to the inlet, where the inlet and outlet are coupled upstream of an intake throttle of the engine.

Abstract: An internal combustion engine includes a cylinder block, an auxiliary machinery attachment member arranged at a side wall of the cylinder block, the auxiliary machinery attachment member to which an auxiliary machine is attached, and a separator portion disposed in a void between the cylinder block and the auxiliary machinery attachment member, the separator portion being provided as a separate member from the cylinder block and the auxiliary machinery attachment member to perform gas-liquid separation on blow-by gas.

Abstract: A blow-by gas processing circuit for an internal combustion engine includes a blow-by gas lead-out pipe uprising from the engine and extending along one side surface of an air cleaner, an upper pipe bending laterally from an upper end of the lead-out pipe and extending along the one side surface, a descending pipe bending downward from an extremity portion of the upper pipe and extending along the one side surface to reach a purification completion chamber of the cleaner, a branch pipe branching downward from an intermediate portion of the upper pipe and connected to a blow-by gas outlet port opened to an intake passage penetrating an insulator member, and a control valve placed in an upper portion of the branch pipe and opening responding to a rise in boost negative pressure of the engine.

Abstract: An engine 40 includes a breather device 20 and an oil passage defining member 30 disposed in the breather device 20. The breather device 20 includes a breather main body 22 integral with a crankcase 50, and a breather cover 24. The breather main body 22 and the breather cover 24 define an enclosed space 26 in communication with an inner space of the crankcase 50. The oil passage defining member 30 includes a first member 32 integral with the crankcase 50, and a second member 34. The first and second members 32 and 34 define an oil passage 38. The crankcase 50 includes a transmission chamber 60 in which a main shaft 72 and a drive shaft 74 are disposed, and oil feed holes 82A to 82C through which the oil passage 38 and the transmission chamber 60 are in communication with each other.

Abstract: A four-stroke engine for a working machine with a rod is provided, where a tool is attached to one end of the rod in a longitudinal direction and the four-stroke engine is fixed to the other end of the rod in use. The four-stroke engine includes: an oil circulation pathway; and a gas-liquid separating chamber configured to separate oil from blowby gas. The gas-liquid separating chamber includes: an inflow part into which the blowby gas is introduced from the oil circulation pathway; oil discharge parts configured to flow the oil separated from the blowby gas back to the oil circulation pathway; and a blowby gas discharge part configured to discharge the blowby gas not containing oil mist from the gas-liquid separating chamber and supplies the blowby gas to an intake passageway to a combustion chamber.

Abstract: An oil separation device of the having a separation chamber configured to separate micron particles of oil from crankcase gas is provided. The separation chamber has passage having a first end and a second end, the second end has a diameter smaller than the first end. The second end is spaced apart from a bottom wall of a chamber. Crankcase gas is drawn along the passage in the same direction as oil falling along the inner wall of the passage. Crankcase gas exits the second end in a path different than oil falling from the second end. The oil separating device may further include a dividing wall having through-holes and a blocking wall disposed above the through-holes so as to facilitate the removal of oil from crankcase gas.

Abstract: An engine apparatus that utilizes a gas pressure regulation valve not only for pressure adjustment but also for removal of lubricant. An engine apparatus includes a blow-by gas returning device to return a leakage of blow-by gas from a combustion chamber to an intake system. The engine apparatus includes an expansion chamber, into which the blow-by gas is introduced from the gas pressure regulation valve. In the expansion chamber, lubricant contained in the blow-by gas is isolated. The blow-by gas is returned to an intake side of an engine from the expansion chamber.

Abstract: A blowby gas processing device including a cylinder block, a cylinder head, a cylinder head cover, an oil separator and a flow velocity amplification device is provided. The cylinder block contains an inter-block passage constituting part of a blowby gas passage passing the blowby gas through in a crank case of an internal combustion engine and introducing the gas into an intake passage of the internal combustion engine. The cylinder head cover contains an in-head passage constituting part of the blowby gas passage provided in at least one of the cylinder head or the cylinder head cover. The oil separator is provided in the inter-block passage and configured to separate and remove oil from the blowby gas. The flow velocity amplification device increases the flow velocity of blowby gas flowing at a bottommost portion provided in the vicinity of the lowest position in the in-head passage.

Abstract: An engine intake manifold is provided. The engine intake manifold includes a manifold chamber configured to receive positive crankcase ventilation (PCV) gas from a PCV conduit outlet, the manifold chamber including a condensate-containment tray with a plurality of baffles to form a plurality of separate cavities below the PCV conduit outlet.

Abstract: Crankcase ventilation filter assemblies are described and shown. Components, features and methods of assembly and use are described. Many of the principles relate to preferred cartridge configurations for engagement with selected housings. Selected optional features described can be used to provide indication to a service provider that a proper cartridge is not positioned appropriately in the housing for use.

Abstract: 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.

Abstract: A flow control valve may include a case and a valve body axially movably disposed within a fluid passage defined in the case. The valve body may have an outer circumferential surface with a flow control surface. The valve body may further include a flange portion positioned on an upstream side of the flow control surface. The flange portion may include a sliding surface and a reference surface. The sliding surface may slidably contact a passage wall surface of the fluid passage. The reference surface may serve as a reference when performing configuration measurement of the flow control surface. The reference surface may extend within a first circumferential range about the axis of the valve body, and the flow control surface may extend within a second circumferential range about the axis of the valve body. The first circumferential range and the second circumferential range may at least partly overlap with each other.

Abstract: Methods and systems are provided for estimating a fuel concentration in engine oil in an engine crankcase. In one example, an engine controller may adjust engine operation such as EGR flow and engine fueling based on the estimated fuel concentration in engine oil. The fuel concentration may be based on an output of an intake oxygen sensor when purge and EGR flow are disabled, engine oil temperature, and fuel composition.

Abstract: Crankcase ventilation filter arrangements and components therefore are described. Example arrangements are described. In one, a serviceable filter cartridge includes a check valve therein, for protection during vehicle rollover. Handle arrangements are also described. Methods of use are described.

Abstract: An outboard motor includes an engine including a crankshaft that is rotatable about a rotation axis extending in an up-down direction, and a crank chamber that houses the crankshaft. The outboard motor includes an oil pan disposed under the engine to retain lubricating oil to be supplied to at least the crank chamber. The outboard motor includes an oil recovery passage and a first blowby gas passage separate from the oil recovery passage. The oil recovery passage extends downward from the crank chamber to the oil pan and is configured to lead lubricating oil inside the crank chamber to the inside of the oil pan. The first blowby gas passage extends downward from the crank chamber to the oil pan and is configured to lead a blowby gas inside the crank chamber to the inside of the oil pan.

Abstract: There is provided an engine device in which a gas purifying filter can be disposed, with high rigidity, in an engine as one of constituent parts of the engine, the need of countermeasures against exhaust gas for each of devices such as vehicles is eliminated, and general versatility of the engine can be enhanced. The engine device includes an engine having an exhaust manifold, and a gas purifying filter which purifies exhaust gas discharged from the engine, front and rear engine leg mounting portions provided on one side surface of the engine include front and rear filter supporting bodies which support the gas purifying filter, the gas purifying filter includes the front and rear filter supporting bodies, and the front and rear filter supporting bodies are connected to the front and rear engine leg mounting portions.

Abstract: A saddle-ride type vehicle is capable of reducing influence of travelling wind on an open end of an air hose, thus preventing fluctuations in the internal pressure of a float chamber of a carburetor. The saddle-ride type vehicle includes a carburetor placed rearward of an engine and an air cleaner placed rearward of the carburetor. An air hose configured to regulate the internal pressure of a float chamber of the carburetor is connected to the carburetor. A recessed portion is provided at a side wall of an air-cleaner case of the air cleaner, the side wall being located along a lateral side of the vehicle. An open end of the air hose is placed at the recessed portion of the air-cleaner case.

Abstract: A first main frame segment 62 extends rearwardly from a head pipe 4, a second main frame segment 64 pivotally supports a swingarm 12, and an engine casing EC is disposed between the head pipe 4 and the swingarm 12. The engine casing EC includes a crankcase section 28, a cylinder part 30, a cylinder head part 32 and a transmission casing section 34. The first main frame segment 64 includes a first mount portion 56, which is connected with a front portion of the cylinder part 30, and a second mount portion 58 which is connected with a rear portion of the cylinder head part 32. The second main frame segment 64 includes a third mount portion 60 which is connected with a rear portion of the transmission casing section 34.

Abstract: A crankcase ventilation device is provided for an internal combustion engine. The crankcase ventilation device includes, but is not limited to an intake air inlet configured to have intake air flowing therethrough, and a crankcase gas inlet configured to have crankcase gas flowing therethrough, and a charge air outlet configured to have charge air flowing therethrough. The crankcase ventilation device is configured to mix inlet crankcase gas with inlet intake air and let it out as charge air, where the intake air inlet, the crankcase gas inlet, and the charge air outlet open into a widening. The crankcase gas inlet opens into the widening at a crankcase gas inlet opening. The distance of the crankcase gas inlet opening from a flow central axis flowing at least through the intake air inlet in one plane is greater than the distance of the intake manifold wall from the flow central axis.

Abstract: A system and method for improving processing of gases contained within the crankcase of an internal combustion engine is presented. The system is especially suited for single boiling point fuels because it allows the storage of such fuels until the fuel can be opportunistically combusted.

Abstract: A vehicle may include an internal combustion engine having a crankcase and a crankcase ventilation device. The crankcase ventilation device may have at least one oil separating device and an oil return that feeds separated oil back to the crankcase. The vehicle may include a conveying device for driving a fluid other than blow-by gas. The conveying device may also drive the blow-by gas in the crankcase ventilation device.

Abstract: Methods and systems are provided for estimating a fuel concentration in engine oil in an engine crankcase. In one example, an engine controller may adjust engine operation such as EGR flow and engine fueling based on the estimated fuel concentration in engine oil. The fuel concentration may be based on an output of an intake oxygen sensor when purge and EGR flow are disabled, engine oil temperature, and fuel composition.

Abstract: A mechanical breather system for a four-stroke engine includes a rotating member. The rotating member can have at least one inlet channel in fluid communication between an outer perimeter of the rotating member and an inner region of the rotating member. A breather housing having an air receiving chamber formed therein is fluidly coupled to the at least one inlet channel of the rotating member. A passage can be formed through a wall of the breather housing is in fluid communication with the air receiving chamber and an exterior of the breather housing.

Abstract: A vehicular engine assembly includes an engine, a panel, and a snorkel. The panel is associated with the engine and includes a panel surface, a first side wall, and a second side wall. The first and second side walls extend substantially upwardly from the panel surface and define a channel. The channel is configured to receive an elongated member. The snorkel includes an attachment tab having a leg member and a foot portion. The foot portion is adjacent to and overlies at least a portion of each of the first and second side walls. The foot portion cooperates with the first and second side walls to constrain the elongated member within the channel.

Abstract: A coalescing filter assembly including a coalescing filter element is provided. The coalescing filter assembly includes a base housing and a cover housing that together form a coalescing chamber. Disposed within the coalescing chamber is the coalescing filter element. The coalescing filter element includes a frame with a partition that separates an unfiltered side from a filtered side of the coalescing filter assembly. A port connects the unfiltered side to the filtered side through the partition. A coalescing tube including coalescing filter media is connected to the port. Unfiltered fluid that enters the coalescing filter assembly is passed through the coalescing filter media such that the contaminants are removed to create a filtered fluid. The filtered fluid exits the coalescing filter assembly at an outlet of the coalescing filter assembly.

Abstract: An oil filter system for a vehicle may provided at a cylinder block of an engine for collecting engine oil from a blow-by gas generated in a crank case. The oil filter system may include a blow-by path to recirculate the blow-by gas so that the blow-by gas generated in the crank case is combusted together with a fuel-air mixture, a filter case that is a space formed between the crank case and the blow-by path, a filter partition disposed to divide the filter case into two spaces, and configured to collect the engine oil contained in the blow-by gas, and an oil pan mounted in the cylinder block for collecting the engine oil that have been collected by the filter partition. The filter partition may collect the engine oil in a forward direction flow and a reverse direction flow of the blow-by gas.

Abstract: Provided are an arrangement capable of reliably preventing freeze of a PCV channel without requiring additional piping and an intake manifold having this arrangement. This arrangement for freeze prevention of a PCV channel includes a PCV channel returning blowby gas containing un-combusted fuel gas as a main component thereof and leaked into an engine to an intake port, an EGR channel returning exhaust gas exhausted from the engine to the intake port, and a heating portion as a common portion between a PCV outer wall of the PCV channel and an EGR outer wall of the EGR channel.

Abstract: A filter element is provided for an air filter assembly of an internal combustion engine including a breather conduit and an intake conduit. The filter element includes a first wall, a second wall, filter media extending between the first and second walls, a first aperture in one of the first and second walls configured to receive air from the breather conduit, and a second aperture in one of the first and second walls configured to deliver air to the intake conduit. The filter media, the first wall, and the second wall define an interior chamber of the filter element. The first and second apertures connect to the interior chamber such that air filtered by the filter media mixes with unfiltered gases provided through the first aperture by the breather conduit prior to exiting the interior chamber through the second aperture into the intake conduit.

Abstract: An intake apparatus includes an intake pipe, a resonator and a blowby gas recirculation pipe. The resonator includes a volume portion having a volume chamber therein and a connecting pipe connecting the volume portion and the intake pipe and having a connecting passage connecting the volume chambera and the intake passage. The blowby gas recirculation pipe includes an internal passage therein. The blowby gas recirculation pipe is connected to an axially midway portion of the connecting pipe, and an exit of the internal passage is connected to the connecting passage of the connecting pipe.

Abstract: A positive crankcase ventilation (PCV) system is provided. The PCV system includes an oil return line coupled to a PCV oil separator and extending through a crankcase housing and a PCV bypass valve positioned in a wall of the oil return line, the PCV bypass valve opening when a pressure in the crankcase exceeds a threshold value and closing when a pressure in the crankcase falls below a threshold value.

Abstract: An internal combustion engine system basically has an internal combustion engine, a reforming fuel injection device and a reformer. The internal combustion engine has an exhaust circulation path that is connected to an exhaust path and an intake path communicating with a combustion chamber. The reforming fuel injection device injects a reforming fuel into an exhaust gas flowing through the exhaust circulation path. The reformer has a reforming catalyst for generating a hydrogen-containing gas using the reforming fuel. The internal combustion engine system has a reforming catalyst regeneration device for causing an oxygen-containing gas to flow through the exhaust circulation path and thereby regenerate the reforming catalyst at a predetermined timing for regenerating the reforming catalyst.

Abstract: An open-ended canister includes a blow-by intake port for receiving contaminated blow-by gases and a fuel vapor exhaust port for venting purified blow-by gases. The open end of the canister is fitted with a removable cover that can be clamped in place. The removable cover includes an oil drainage port for draining cleansed engine oil back to the crankcase of the engine. The canister contains a filtering assembly made of multiple layers of metal mesh of differing gauges. The metal mesh may include one type of metal or several types of metal.

Abstract: Methods and systems are provided for generating vacuum from crankcase ventilation flow. During both directions of gas flow between an engine intake manifold and a crankcase, gases are directed through one or more aspirators to produce vacuum. The drawn vacuum may then be used to operate various engine vacuum actuators.

Abstract: Systems and methods are provided for engine systems including a vacuum-powered multiple tap aspirator coupled between atmospheric, an engine crankcase, or another source and a vacuum source such as a compressor inlet or engine intake manifold. The multiple tap aspirator includes a suction tap arranged in a throat of the aspirator, a suction tap arranged in a diverging cone of the aspirator, and a suction tap arranged in a straight exit tube downstream of the diverging cone of the aspirator. The aspirator provides vacuum generation and suction flow over a range of vacuum levels at the suction taps, and suction flow only passes through a single check valve before entering the aspirator.

Abstract: An intake system for an internal combustion engine, having a structure in which blow-by oil and/or fuel entering into an air cleaner case can be discharged to the outside of the air cleaner case. The intake system for an internal combustion engine is provided in which air is sucked from a clean air chamber in the air cleaner case into a throttle body provided with a throttle valve through a funnel while defining an airflow passage. Concurrently, fuel is sprayed from an injector, thereby feeding the fuel-air mixture into an intake port. A bypass passage different from the airflow passage is provided between the clean air chamber in the air cleaner case and the throttle body. The bypass passage is so structured that a passage inlet thereof on the clean air chamber side opens at an inner wall surface of the air cleaner case.

Abstract: An assembly for use in a crankcase ventilation system of an internal combustion engine includes a shutter arrangement that is constructed and arranged for preventing that residual gases and/or vapors out of a crankcase flow into an air intake system during a period of time that starts at shut down of the engine and ends after it has been re-started. The assembly also includes an outlet that is constructed and arranged for removing at least a substantial part of the residual gases and/or vapors from the engine as long as it is shut down.

Abstract: An intake manifold assembly includes an intake manifold body defining an interior manifold cavity. The intake manifold further includes a throttle mount coupled to the intake manifold body and defining a mount passage in fluid communication with the interior manifold cavity. The throttle mount is configured to be coupled to a throttle assembly. The intake manifold assembly further includes a supplemental gas conduit including a first supplemental gas conduit portion coupled to the intake manifold body. The supplemental gas conduit further includes a second supplemental gas conduit portion in fluid communication with the first supplemental gas conduit portion. The second supplemental gas conduit portion is coupled to the throttle mount and is configured to deliver supplemental gases into the mount passage to mix the supplemental gases with intake air flowing through the mount passage.

Abstract: A portable engine generator includes a power generation unit operating an engine to generate electricity and a negative pressure fuel cock using a negative pressure in a crank chamber as an operating negative pressure to supply fuel to the engine. The negative pressure fuel cock is located on a side opposite to a negative pressure take-out port of the crank chamber with respect to a position of the power generation unit when the portable gas-engine generator is turned over, and so as to be located at a position higher than the negative pressure take-out port when the portable gas-engine generator is in an upright posture.

Abstract: Breather mechanism includes a breather passage opening into a crankcase, a breather chamber communicating with the crankcase via the breather passage, and a valve provided in the breather chamber and openable to allow blow-by gas to flow from the crankcase into the breather chamber once inner pressure of the crankcase exceeds a predetermined value. When the engine is placed in a laterally laid-down position, entry, into the breather chamber, of lubricating oil is prevented by the breather passage. When the engine is placed in a vertically upright position, an outlet end portion of the breather passage is located above an inlet end portion of the breather passage.

Abstract: A gas-liquid rotating coalescer includes first and second sets of one or more detent surfaces on a rotary drive member and a driven annular rotating coalescing filter element which engagingly interact in interlocking mating keyed relation to effect rotation of the coalescing filter element by the rotary drive member. Designated operation of the coalescer requires that the coalescing filter element include the second set of detent surfaces. A coalescing filter element missing the second set of detent surfaces will not effect the noted designated operation.