EP2108790B1 - Oil/air Separating device equipped with a filtering medium, designed to filter blowby gases of an internal combustion engine. - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to devices for separating elements suspended in a gas from an internal combustion engine casing. The field of application of the invention relates in particular to the separation of liquid crankcase gases in the engines of road vehicles (eg automobiles, trucks, motorcycles), boats or industrial engines (eg generator).

BACKGROUND OF THE INVENTION

The materials issuing from the casing include, on the one hand, a liquid part such as an aerosol whose distribution in number of droplets is centered, for example, around 0.6 μm and a film of oil deposited on the housing walls, and secondly, a gaseous portion such as fuel vapors, water or oil, and finally a solid portion such as soot suspended in the gas or in the liquid contained in the crankcase.

Due to segmentation leakage and valve leakage, unburnt gases enter the crankcase causing an increase in crankcase pressure. In order to prevent this pressure inside the casing from becoming too great, these gases must be evacuated while knowing that the regulations imposed prohibit the evacuation of gases from being done in the environment. Thus, in a manner known per se, the casing is connected to the air intake of the internal combustion engine via a separation device in order to evacuate continuous these gases; this is more commonly known as the circuit for recycling crankcase gas or blow-by gas by a person skilled in the art.

Various crankcase separation means are employed in the prior art, of which four large families can be distinguished.

A first family brings together the chicane systems. A network of baffles is formed of several plates arranged to accelerate and sharply deflect the flow of gas. This results in an agglutination of the oil drops on these plates after impact and therefore de-oiling of the gas. A pressure regulating valve (PRV) is generally placed downstream of the baffles. These systems are usually arranged in the cylinder head cover or in a box attached to the engine. These systems generate little loss of load. However, they are not very effective for the separation of very fine oil aerosols.

A second family brings together the cyclone devices. The conical volume into which the gas enters through a tangential inlet allows the acceleration and rotation of the gas. This rotation causes the oil drops to impinge on the walls of the cyclone, while the gaseous phase is evacuated by the outlet provided in the center. These devices are mounted either in a specific box attached to the engine, or in the oil module or in the cylinder head cover. These systems are not very effective. They become more complex by the addition of progressive opening valves cyclonic cells with the flow of gas. The pressure regulating valve is often superimposed on cyclones.

A third family groups the centrifugal separator systems. Such systems include a network of disks or cups rotating about an axis of rotation. The crankcase gases are rotated by the rotation of the system. The oil droplets are expelled radially outwards while the purified gases exit at the center of the separator system. These systems are typically rotated either by an electric motor or by the camshaft or crankshaft, or by a Pelton wheel using the engine oil pressure. They are very efficient separators and generate no or little loss of load. They are placed in a box attached to the engine or integrated into the cylinder block or distribution. The pressure regulating valve is superimposed on the separator or offset.

A fourth family groups coalescing filters. These filters include a network of fibers for the capture of fine oil droplets. The oil droplets then gather together to form larger drops capable of sliding by gravity along the media. These filters are typically placed in a housing attached to the engine, in the oil filter module or in the cylinder head cover. They are effective (separation efficiency of 50 to 80%) but can become dirty and generate pressure drop. The pressure regulating valve is often superimposed on the coalescer filter.

In this fourth family, and as described in the document WO 00/71862 there are known oil separator filters for the purification of the crankcase gases, which allow the removal and replacement of the separating element. It is provided for this purpose a specific filter housing connected to an oil return pipe and comprising a cover to which is attached a filter cartridge. This type of separation filter for crankcase gases is however cumbersome: it occupies as much space as an oil filter. This disadvantage limits use.

To the problem of congestion is added the concern to install the separator as close as possible to the engine to prevent cooling of gases during their journey to the separator. Cooling is undesirable because of the condensation of water that then occurs upstream of the separator. This water can form with the oil a heterogeneous amalgam (commonly designated by the skilled person under the term "sludge") likely to obstruct the pipes and valves.

It is known, by the document US 2006/081229 , a filter device arranged at an oil filler neck, with a filter element fixed between the outer wall of the chute and a long central filling pipe. The size of this filter device, however, remains important.

We know from the document GB 1 395 744 a plug for sealing an oil filling orifice, wherein an oleophobic filter is arranged in a cylindrical cavity of the plug body.

The document US 4,401,093 shows a separation device in which a filter is located at a breather plug, this device having the features of the preamble of claim 1.

GENERAL DESCRIPTION OF THE INVENTION

The present invention aims to overcome one or more of the aforementioned drawbacks by providing a device for filtering elements in suspension in a gas from a crankcase, which is of minimal size and whose filtering part can be replaced.

For this purpose, the invention is as defined in claim 1.

Thanks to these arrangements, the filter medium integrates into the filling chamber and is easily accessible for allow it to be replaced or a simple check of its condition. Thus, the plug which is commonly called oil plug is no longer independent of the crankcase separation system. Observation of the filter medium is systematic at each emptying and filling: this is important to put the user in confidence since we can not predict the life of a filter. In case of clogging or fouling (filter engulfed by a water / oil mixture) it suffices to unlock the cap, typically by a rotational movement. The oil plug has a shape making it easier to grip for loosening. The locking can be achieved by a bayonet or a net.

According to another feature, the separating element extends between two flanges and is held completely in the interior volume of the oil filling chamber when the plug closes the oil filling opening. The overall height of the device can be advantageously reduced since the filter media can be interposed inside the oil supply chamber, between the inlet and the outlet of the gas.

• une première partie préhensible placée à l'extérieur de l'élément de canalisation; et
• une deuxième partie pénétrant à l'intérieur de l'enceinte de remplissage d'huile, permettant de rendre solidaire du bouchon l'élément de séparation, et présentant un orifice transversal à travers lequel la zone aval communique avec l'orifice de sortie

According to another feature, the removable cap is in two parts in the closed position:

• a first grip part placed outside the pipe element; and
• a second part penetrating inside the oil filling chamber, making it possible to make the closure element integral with the separating element, and having a transverse orifice through which the downstream zone communicates with the outlet orifice;

Thus, the insertable portion of the plug can cooperate with the outlet channel of the filtered gases. The fixing elements of the plug are for example configured so as in the closed position, the angular position of the transverse orifice corresponds to that of the outlet orifice.

According to another feature, the device is as defined in claim 4. Thus, the passage of the crankcase gases through the filter medium is made mandatory.

According to another feature, the device is as defined in claim 5. Thus, the seal can be obtained by simply clamping the plug in rotation at a level greater than that where the stopper retaining members (thread, bayonet type element, etc.).

According to another feature, the device is as defined in claim 6. This flexible membrane thus prevents any excessive depression in the housing, which would be likely to cause a call air from outside to the housing inducing therefore deterioration of the seals disposed between the housing and the engine block. In this embodiment, it is understood that three functions (oil filling, crankcase treatment and pressure regulation) are integrated in one place.

According to another feature, the device is as defined in claim 7. The device thus provides a bypass to the output in case of overpressure of the housing or possible overpressure of the upstream zone due to a problem of fouling of the filter media.

According to another feature, the device is as defined in claim 8. Thus the drops of oil recovered by coalescence on the downstream side of the filter media can be recovered without being directly discharged into the upstream zone where crankcase gases flow.

According to another feature, the oil collector comprises an elastically deformable member for purging the collected oil. Advantageously, the oil can be purged during the stopping of the engine, when the hydrostatic pressure generated by the level of the oil collected overrides the negative pressure difference between upstream and downstream.

According to another feature, the oil filling chamber is formed by the cylinder block and the cylinder head cover of the engine.

According to another feature, the oil filling chamber is formed by a tubular conduit.

Furthermore, the subject of the invention is also a stopper plug for an oil filling line for lubricating an internal combustion engine, intended for a separation device according to the invention. This plug is in section in the form of a T and comprises a flattened grippable portion and an insertable portion on which is fixed the filter media.

• un rétrécissement de contour extérieur tel que le contour extérieur de la partie préhensible du bouchon est plus grand que le contour extérieur de la partie insérable du bouchon au niveau du débouché de la conduite ; et
• un orifice transversal interposé entre l'élément de séparation et ledit rétrécissement.

According to another particularity, the plug has:

• an outer contour narrowing such that the outer contour of the gripping portion of the plug is larger than the outer contour of the insertable portion of the plug at the outlet of the pipe; and
• a transverse orifice interposed between the separating element and said narrowing.

Thus, the stopper can retain a compact outer shape. This form is for example that of a disk facilitating the grip for loosening.

• un flasque supérieur formant une extrémité supérieure de l'élément de séparation ;
• un flasque inférieur, le média filtrant étant interposé entre le flasque supérieur et le flasque inférieur ; et
• un collecteur d'huile s'étendant axialement depuis le flasque inférieur et formant une extrémité inférieure de l'élément de séparation.

The invention also relates to a gas-suspended element separating element comprising a filter medium, intended to be disposed in the abovementioned plug, the separating element having a central axis of revolution around which the medium is disposed. filtering and being characterized in that it comprises:

• an upper flange forming an upper end of the separating member;
• a lower flange, the filter medium being interposed between the upper flange and the lower flange; and
• an oil collector extending axially from the lower flange and forming a lower end of the separating member.

Thus, the separation element is a filter cartridge adapted for the treatment of crankcase gases which is simple in design and compact. This separating element can be inserted in an oil filling chamber without contact with the side walls of the enclosure and can be easily controlled by simple manipulation of the plug with which it is associated.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1 est une vue schématique en coupe axiale du dispositif de séparation selon un premier mode de réalisation conforme à l'invention ;
• la figure 2 est une vue schématique en coupe axiale d'un second mode de réalisation du dispositif conforme à l'invention ;
• la figure 3 est une vue schématique en coupe axiale du dispositif selon un troisième mode de réalisation conforme à l'invention ;
• la figure 4 est une vue schématique en coupe axiale du dispositif selon un quatrième mode de réalisation de l'invention ;
• la figure 5 est une vue schématique en coupe axiale du dispositif selon un cinquième mode de réalisation de l'invention ;
• la figure 6A est une vue suivant la coupe VIA-VIA des figures respectives 1 et 3 ;
• la figure 6B est une vue suivant la coupe VIB-VIB de la figure 2.

Other features and advantages of the invention will become apparent from the following description of several embodiments, given by way of non-limiting examples, with reference to the accompanying drawings in which:

• the figure 1 is a schematic view in axial section of the separation device according to a first embodiment according to the invention;
• the figure 2 is a schematic view in axial section of a second embodiment of the device according to the invention;
• the figure 3 is a schematic view in axial section of the device according to a third embodiment according to the invention;
• the figure 4 is a schematic view in axial section of the device according to a fourth embodiment of the invention;
• the figure 5 is a schematic view in axial section of the device according to a fifth embodiment of the invention;
• the Figure 6A is a view along the VIA-VIA section of the respective figures 1 and 3;
• the Figure 6B is a view along section VIB-VIB of the figure 2 .

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

In the various figures, identical references indicate identical or similar elements.

With reference to Figures 1 to 5 , the separation device 10 separates the liquid and possibly solid parts of certain materials produced by the internal combustion engine and which are directly from the housing.

On the Figures 1 to 4 this separating device 10 is disposed in an oil filling chamber in the form of a tubular pipe wall 11 opening at an upper end 11a at an opening 12 for the filling of lubricating oil. of the motor. Without limitation, the separating device 10 can be placed in the CC head cover (as illustrated figure 5 ) or in an oil filling column (as illustrated by the Figures 1 to 4 ). The pipe wall 11 has a inlet port 13 communicating directly via an inlet conduit 14 with the housing (not shown) of the internal combustion engine. It is therefore from this inlet 13 that the untreated crankcase gases arrive. The pipe wall 11 has at its upper part a central axis A corresponding for example to an axis of symmetry of the opening 12.

In the interior volume defined by the pipe wall 11, a separating element 15 is provided for extracting crankcase gases from the liquid and solid particles. The separating element 15 comprises a filtering medium 16 which extends between a first flange called upper flange 17 and a second flange called lower flange 18 in the example considered here.

As can be seen, the upper flange 17 is supported by a plug 20 for closing the opening 12. The cap may be based on plastic material (s). In the closed position of the plug 20, the separating element 15 delimits an upstream zone Z1 of untreated gases communicating with the inlet orifice 13 and a downstream zone Z2 of treated gases communicating with an outlet orifice S formed in the pipe wall 11.

As illustrated by the arrows, the blow-by gases to be treated may be gases G which come from the high engine part and / or gases G 'which come from the low engine part. The crankcase gases pass through the separating element 15 and emerge purified by the outlet cannula 21 towards the air intake. In the case of integration into the CC head cover as illustrated in figure 5 there is no inlet pipe 14.

While the gases G which come from the high motor part are conveyed by the inlet pipe 14, the gases G 'which come from the low motor part go up by a lower entry of the pipe element 11. Alternatively or in a complementary manner, a specific pipe in connection with the low engine can join the inlet pipe 14.

As illustrated in the figures, the removable plug 20 has a gripping portion 22 and an insertable portion 23 penetrating into the interior volume of the pipe wall 11. This insertable portion 23 comprises means for fixing the separation element 15. The filter media 16 is thus placed in the extension of the plug 20 and can be removed with the latter. The general shape of the gripping part is flattened to limit the height requirement outside the channel formed by the wall 11. The attachment of the separating element 15 can be made removably as shown in FIG. figure 5 for example, using elastic tabs, clips, screwing system or insertion studs or any other suitable system. In this case only the separating element 15 can be replaced. Alternatively, the separation element 15 may be an integral part of the plug 20. The filtering medium is preferably a coalescer media. It can be rolled up or folded. It is understood that a superimposed and preferably coaxial arrangement of the plug 20 and the filter medium 16 facilitates the complete output of this assembly.

In the example of the figure 1 , the plug 20 has a shoulder 24 or narrowing of similar section such that the outer contour of the gripping portion 22 is greater than the outer contour of the insertable portion 23. A seal 25 may be fixed on the shoulder 24. This seal 25 comes into contact with the periphery of the oil filling opening 12. In the insertable portion 23 is provided a transverse bore 26 interposed between the upper flange 17 of the separating member 15 and the shoulder 24. The treated gases of the downstream zone Z2 pass through this drilling 26 then through the outlet port S to then flow to the air intake.

The separation between the upstream zone Z1 and the downstream zone Z2 is effected by a peripheral sealing element 30 in contact with the pipe wall 11. This sealing element 30 is placed above the filter medium 16, at the level of the lower end of the plug 20 which is fixed the upper flange 17.

With reference to the figure 1 , an annular sealing flange 30 is placed between the plug 20 and the separating element 15 to prevent the passage of gases elsewhere than through the filter medium 16. In the closed position of the plug 20, the flange 30 comes sealingly abut an annular rim 31 projecting or complementary flange towards the inside of the pipe wall 11. In the embodiment of the figure 1 , this flange 31 extends for example perpendicularly to the central axis A. When closing the plug 20, the flange 31 enters a groove g of the insertable portion 23 formed between the annular flange 30 and the element locking 32. The locking of the stopper can be achieved by means of a bayonet, a net or any other suitable restraint.

It is understood that the collar 30 illustrated in FIG. figure 1 can be replaced by an O-ring T as shown in figure 4 , locally producing a radial seal between the upstream zone Z1 and the downstream zone Z2. The collar 30 can be placed above or below the locking system of the stopper 20.

The flange 30 is for example made in the material of the plug 20 or may be made of elastomer overmolded to the plug 20. This improves the seal. The outlet port S of the purified gases GP recovered in the downstream zone Z2 can be made between the collar 30 and the prehensile sealing portion 22 of the plug 20. In order to allow easy removal of the assembly, the outlet orifice S in connection with the outlet cannula 21 is formed in the body of the pipe wall 11 and not in the plug 20.

In the embodiment of the figure 2 , the seal 25 is fixed below the shoulder 4, on the insertable portion 23. This seal 25 comes radially in contact with the inside of the pipe wall 11. The transverse bore 26 is interposed between the seal 25 and flange upper 17 of the separating element 15.

As is visible on the figure 2 the separation between the upstream zone Z1 and the downstream zone Z2 is effected by the upper flange 17 which bears against the annular flange 31. In this case, the upper flange 17 has an outside diameter slightly smaller than the diameter of the flange 17. opening 12 for filling the oil and greater than the outside diameter of the lower flange 18.

With reference to Figures 1 and 2 , the lower flange 18 is integral with an oil collector 33 fed via a central opening 34 of the lower flange 18. The oil coalesced on the downstream side of the filter media 16 falls by gravity as illustrated by the arrow H in this collector 33 placed opposite the prehensile sealing portion 22 of the plug 20. The bottom 35 of the collector 33 preferably has a large surface area with, for example, a diameter substantially equal to the outside diameter of the filter medium 16 to increase the oil content without excessive bulk in the axial direction.

The manifold 33 has a purge opening 35 closed by an elastic member 40 or a valve. During operation of the engine, the pressure difference holds the elastic element 40 against the lower surface of the manifold 33. When the engine is stopped, the pressures are equilibrated and, under the weight of the oil contained in the manifold 33, the elastic member 40 moves away from the lower surface of the manifold 33, which allows the oil to flow to the oil sump. engine oil. The elastic element 40 may consist, for example, of a spring blade or similar resilient return member.

With reference to figures 1 and 6A the shape of the passage defined by the rim 31 may be wider on either side of a median plane. The locking element is constituted in this case by two flange portions each having a shape corresponding to one of the extensions of the passage. This is a bayonet type closure.

In the example of figures 2 and 6B , the shape of the passage defined by the flange 31 is circular. The locking can be obtained by screwing the plug 20 near the outlet of the pipe wall 11. Closing by clipping or snapping the plug 20 can also be achieved.

Referring now to Figures 3 and 4 , the separation device 10 has the same characteristics as that described above, in addition to the integration of a valve PRV (Pressure Regulation Valve) in the plug 20. This valve can be formed essentially of a flexible membrane 41 which has an outer edge stuck or sealingly attached to the plug 20, so as to separate the downstream zone Z2 from an inner volume 200 of the plug 20 which is subjected to atmospheric pressure by means of a small orifice 42 venting formed in the gripping portion 22 of the plug 20. This vent hole 42 is shown axially but may be placed differently. The plug 20 is for example provided with a groove or circular groove in which is housed the outer edge of the membrane flexible 41.

In the example of Figures 3 and 4 , the membrane 41 is biased by a spring 43 which bears on a wall of the bore 26 of the insertable portion 23. The membrane is thus prestressed by this spring 43. When the intake suction increases, the diaphragm 41 moves to its seat 44. This displacement then creates a pressure drop that limits the vacuum upstream of the diaphragm 41. Under normal operating conditions, the spring force is determined so that the diaphragm 41 is kept away from the outlet. a conduit 45 adjacent to the adjacent piercing 26. In the event of a high depression in the upstream zone Z1, the spring 43 may compress so that the membrane 41 covers the duct 45 and separates the downstream zone Z2 into two sectors: one in depression on the side of the filter media 16 and the other side of the outlet orifice which is then no longer or almost no longer supplied with gas by the separating device 10. A regulation is obtained by the valve thus formed.

In the embodiment of the figure 3 , the gases are discharged through the bore 26 which is in the form of an outlet channel opening between the gripping portion 22 of the plug 20 and the flange 30 sealing between the upstream zone Z1 and the downstream zone Z2. This seal is obtained in the same way as for the example of the figure 1 . The form illustrated in Figure 6A therefore also corresponds to the case of figure 3 . As a variant, the type of shape illustrated in FIG. Figure 6B can also be applied to a separation device 10 provided with a flexible diaphragm 41 for pressure regulation. The thread lock mode as indicated in the figure 2 or a similar fixation can be used in this case.

With reference to the figure 4 , the separation device 10 has the same functions and a structure analogous to that described in figure 3 . The tightness between the upstream zone Z1 and the downstream zone Z2, on the other hand, is obtained by an O-ring T placed at the periphery of the insertable portion 23 of the plug 20, below the bore 26.

In a variant of the embodiments illustrated by the Figures 1 to 4 , the orifice or bore 26 may be provided in the upper flange (17) of the separating element (15).

An embodiment of the invention will now be more particularly described in connection with the figure 5 .

In this embodiment, the separating device 10 is not placed inside a specific tubular duct but directly integrated with the motor's DC cover. The oil filling chamber is then constituted by the body 1 of the cylinder head of the engine and the valve cover CC. The cylinder head cover CC has a circular opening 12 surmounted by a tubular portion of revolution and axis A intended to receive the filler cap 20. This tubular portion 11a constitutes the upper end 11a of the filling chamber.

The separating device 10 has, as in the previously described embodiments, a plug 20 with a flattened gripping portion 22 and an insertable portion 23 which penetrates into the filling aperture 12. The plug 20 is in section in the general form of a relatively flattened T. In this embodiment, liquids such as water or oil are separated in the downstream zone Z2 and collected in the manifold 33. The device 10 always has a separating element 15 connected to the plug 20. This separating element 15 is here made integral rotation of the plug 20. As for the previous modes of embodiment, the filter medium 16 has a coalescent function for the liquid particles such as oil and water, and a filtration function of solid particles such as soot. It will be noted that in this embodiment, the outlet cannula 21 is made in the breech cover CC.

As for the embodiments illustrated by the Figures 1 to 4 , the upper flange 17 separates in its equilibrium state the upstream zone Z1 of the outlet orifice S. However, in this embodiment, the upper flange 17 is to be moved upwards when there is an overpressure in the casing and when the gases present in the body 1 of the cylinder head are at a sufficiently high pressure to lift the separating element 15 and this against the force exerted by the spring R. When this separating element 15 is moved upwards, the outlet port S is then directly accessible and the gases can then be directly routed to the outlet cannula 21 which is connected to the air intake of the internal combustion engine.

In the example considered here, the spring R is disposed between the gripping part 22 and the separating element 15 so that the separating element 15 naturally obturates the access from the bottom to the outlet port S leading to the outlet pipe or cannula 21. This closure by the upper flange 17 therefore forces the gases arriving through the lower end of the body 1 of the cylinder head to pass directly through the filter media 16 to then arrive in the downstream zone Z2 through which the filtered gases will then be directly routed to the air intake of the internal combustion engine via the outlet cannula 21.

It is understood that the separating element 15 can move in translation relative to the plug 20 between a position distant from the upper end 11a of the filling chamber and a position close to the upper end 11a. For this, the fixing of the separating element 15 can be done using elastic pins 46 or similar retaining elements provided at the lower end of the gripping portion 23 of the plug 20. These elastic pins 46 form a defining stop for the separating element 15 a low or remote position relative to the cap 20. The lugs or radial projections of the upper flange 17 inward then bear against this stop.

In the remote position, the outer edge of the upper flange 17 rests on a transverse wall 47 so that only the downstream zone Z2 communicates directly with the outlet orifice S, this downstream zone Z2 being situated at the level of the upper end 11a. of the filling chamber. As is visible on the figure 5 , the upper flange 17 of the separating element 15 is biased by the spring R downwards to allow the passage of the purified gas GP via the filter medium 16 to the outlet orifice S.

An overpressure of the casing gases G raises the upper flange 17 to thereby define a bypass or bypass to the outlet. In this position close to the upper flange 17 with respect to the end 11a, it is understood that the casing gases G arriving through the inlet orifice 13 can be discharged through the outlet orifice S without passing through the filter media 16.

This derivation can also be carried out when the separating element 15 or more exactly its filter medium 16 is fouled and can no longer ensure proper separation. In this case, the casing gases G can no longer be filtered and pass through the filter element 16, so that the overpressure of the gases in the upstream zone Z1 will cause the separation element 15 to rise. against the force exerted by the spring R so as to put in direct communication the inlet pipe 14 with the outlet port S gas.

One of the advantages of the invention is to provide an effective separation of the crankcase gases closer to the engine, with the ability to easily control the condition of the filter media and if necessary replace it. The size of the separating device 10 is furthermore greatly reduced since separation is effected in the oil filling line, which is an already existing element.

It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed.

Claims (13)

1. Device (10) for separating elements suspended in a gas emitted from a casing of an internal combustion engine, comprising:

   - at least one oil refilling enclosure (1, 11) having a top end (11a) with a central axis (A) of revolution and a bottom end (11b), the oil refilling enclosure (1, 11) communicating with the engine casing,

   - a removable piece forming a cap (20) for closing off said top end (11a),

   - a separating element (15) comprising a filtering medium (16), the separating element (15) being supported by the removable cap (20) and delimiting an upstream zone (Z1) for untreated gases communicating with the engine casing and a downstream zone (22) for treated gases communicating with an outlet orifice (S) for evacuating treated gases,

   said bottom end (11b) being on the side of the upstream zone (Z1) and communicating with the oil casing of said engine,
   the top end (11a) of said enclosure (1, 11) defining an opening (12) when the cap (20) is removed to enable filling with oil in order to lubricate said engine,
   characterised in that said outlet orifice (S) is disposed in a wall of said enclosure and is connected to the air intake of the internal combustion engine.
2. Device as claimed in claim 1, in which the separating element (15) extends between two flanges (17, 18) and is retained entirely inside the interior volume of the oil refilling enclosure (1, 11) when the cap (20) is closing the oil refilling opening (12).
3. Device as claimed in one of claims 1 and 2 in which the removable cap (20) comprises two parts in the closed position:

   - a first prehensible part (22) positioned on the exterior of the channelling element; and

   - a second part (23) penetrating the interior of the oil refilling enclosure (1, 11), enabling the separating element (15) to be joined to the cap (20) and having a transverse orifice (26) via which the downstream zone (Z2) communicates with the outlet orifice (S).
4. Device as claimed in claim 3, in which the second part (23) of the cap has at least one peripheral seal element (T, 30) in contact with the oil refilling enclosure (1, 11) and separating the upstream zone (Z1) and the downstream zone (Z2) in a sealed arrangement.
5. Device as claimed in claim 4, in which the oil refilling enclosure (1, 11) has an annular internal edge (31) on the side of said top end extending perpendicular to the central axis (A), said peripheral seal element having at least one annular collar (30) seated on the edge (31) in a sealing arrangement.
6. Device as claimed in one of claims 1 to 5, in which the cap (20) has a flexible membrane (41) on the inside, positioned either in a first position in which it permits communication between the inlet orifice (13) and the outlet orifice (S) or in a second position in which it prevents communication between the inlet orifice and outlet orifice, the cap also having a venting orifice (42) to expose a first face of the flexible membrane (41) to atmospheric pressure.
7. Device as claimed in one of claims 1 to 6, in which the downstream zone (Z2) is disposed on a level with the top end (11a) of the oil refilling enclosure (1, 11), the separating element (15) rotating in unison with the cap (20) and being displaceable in vertical translation relative to the cap between a position at a distance apart from the cap (20) in which only the downstream zone (Z2) communicates with the outlet orifice (S) and a position close to the cap (20) in which the casing gases present in the oil refilling enclosure (1, 11) can be evacuated via the outlet orifice (S) without passing through the filtering medium (16).
8. Device as claimed in one of claims 1 to 7, in which the separating element (15) extends between what is a top flange (17) connected to the cap (20) and what is a bottom flange (18) which is farther away from the cap (20) and joined to an oil collector (33), the filtering medium (16) being an oil coalescer.
9. Device as claimed in claim 8, in which the oil collector (33) comprises an elastically deformable element (40) enabling the collected oil to be purged.
10. Device as claimed in one of claims 1 to 9, in which the oil refilling enclosure (1, 11) comprises the cylinder block (1) and the cylinder cover (CC) of the engine.
11. Device as claimed in one claims 1 to 9, in which the oil refilling enclosure (1, 11) is provided in the form of a tubular conduit (11).
12. Closure cap for an oil refilling conduit for lubricating an internal combustion engine, designed for use with a device (10) as claimed in one of the preceding claims, the cap (20) having a T-shaped section and comprising a flat, prehensible part (22) on the one hand and an insertable part (23) to which a filtering medium (16) is affixed on the other hand.
13. Element (15) for separating elements suspended in a gas, comprising a filtering medium (16) designed to be disposed in a cap as claimed in claim 12, the separating element (15) having a central axis of revolution about which the filtering medium (16) is disposed and being characterised in that it comprises:

    - a top flange (17) forming a top end of the separating element (15);

    - a bottom flange (18), the filtering medium (16) being disposed between the top flange (17) and bottom flange (18); and

    - an oil collector (33) extending axially from the bottom flange (18) and forming a bottom end of the separating element (15).

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