FR3092360A1 - Separator device with at least one cyclone and method for separating oil from crankcase gases of an internal combustion engine - Google Patents

Abstract

The device (10) for separating the crankcase gases (G) comprises an oil filling chamber (1) having a tubular upper end (11a) and a lower end (11b) with a gravity flow outlet (7) of oil. The upper end forms an oil filling opening (12) for lubricating the engine. The gases (G) are fed and treated in a separation chamber (18) of a cyclone (15) placed in the enclosure (1). The cyclone (15) delimits the chamber (18), located under the plug (20) in the shut-off configuration, and a gravity flow of oil separated into this chamber and / or fresh oil introduced through the opening ( 12) is carried out via the lower outlet (7) in communication with the oil sump. A chimney (19) of the cyclone (15) communicates with the outlet (S) of the device, via a hollow (20c) of the plug (20), in order to axially evacuate the gases treated in the chamber from above. separation (18). Figure for the abstract: F i gure 3

Description

SEPARATOR DEVICE PROVIDED WITH AT LEAST ONE CYCLONE AND METHOD FOR SEPARATE OIL FROM THE CRANKCASE GAS OF AN INTERNAL COMBUSTION ENGINE

The invention relates to the separation of liquid from the crankcase gases in the heat engines of road vehicles (e.g. cars, heavy goods vehicles, motorcycles), boats or industrial heat engines (generator for example).

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

Because of the leaks at the segmentation and at the level of the valves, gases loaded with unburned substances are introduced into the crankcase causing an increase in the pressure of the crankcase. In order to prevent this pressure inside the casing from becoming too great, these gases must be evacuated knowing that the regulations imposed prohibit the evacuation of the gases from taking place into 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 continuously evacuate these gases; this is what is more commonly called the crankcase gas or blow-by gas recycling circuit by those skilled in the art.

Various means of crankcase gas separation are employed in the prior art, including baffle systems, filter elements and cyclone separators. However, baffle systems, forming impaction walls, are not very effective for the separation of very fine oil aerosols. Their use is therefore limited, especially when there are significant constraints to limit the size.

In the family of filtering elements, separation involves coalescing filters. Such filters include a network of fibers allowing the capture of fine oil droplets. The oil droplets then coalesce 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 filtration module or in the cylinder head cover. They are effective (separation efficiency of 50 to 80%) but can clog up and generate pressure drop. Document EP 2108790 discloses a space-saving solution using a filter insert mounted under a cap covering an oil filling enclosure. The filter medium is then easy to access to allow its replacement or a simple check of its condition.

There is a need for compact and durable solutions (not requiring a spare stage for example), making it possible to carry out the separation as close as possible to the engine to avoid cooling of the gases and any phenomenon of water condensation during their route to the separator.

OBJECTS OF THE INVENTION

According to the invention, a separation device is proposed for separating elements in suspension in a gas issuing from an internal combustion engine crankcase, the device comprising:
- an oil filling enclosure comprising an upper end, a lower end, and a passage communicating with the engine casing forming an inlet of the device,
- a removable cap to seal the upper end, this upper end being tubular extending around a central axis to form an oil filling opening for engine lubrication when the cap is removed,
- a separation chamber placed under the cap,
- an outlet orifice for the evacuation of gases which have been treated in the separation chamber,
- a lower outlet for the gravity flow of oil separated into the separation chamber and/or of fresh oil introduced through the filling opening, the lower outlet being located in the lower end and in communication with the casing of oil of said engine, and
- a cyclone forming/including a separation chamber and provided with a chimney, in communication with the outlet orifice, for the axial evacuation from above of the gases treated in the separation chamber.

With this arrangement, there is advantageously a cyclone whose efficiency is satisfactory and which limits the size, without making assembly more complex. Thus, the plug commonly called the oil plug is no longer independent of the crankcase gas separation system. The cyclone is not prone to clogging and can thus provide long-lasting separation.

The oil plug has a shape that makes it easier to grip for loosening. Locking can be achieved by a bayonet or a net. Compared to a filter medium, the part of the separation device secured to the cover can be drier. For example, only the chimney and an upper flange of the cyclone can be attached to the cap. Alternatively, the entire cyclone can be moved in one piece with the plug.

According to one feature, the cyclone includes:
- a conical wall whose cross-section decreases towards the lower outlet as it moves away from the upper end, the separation chamber being at least partly delimited by the conical wall,
- A lateral admission inlet, preferably tangential, to pass raw gases from the inlet of the device into the separation chamber; and
- said chimney for evacuating the gases treated in the separation chamber, in communication with the outlet orifice in communication with the outlet orifice (S), the chimney extending parallel to and being crossed by the central axis (AT).

Typically, the chimney is secured to the plug, and/or the chimney is arranged directly above a closure part of the plug, parallel to the central axis.

It is understood that the cyclone can be arranged interposed between the stopper (above) and the lower outlet (below), being vertically aligned with the stopper and the low point of the device where the lower outlet is formed.
In embodiments of the separation device according to the invention, one or more of the following characteristics may be used:
the chimney of the cyclone communicates with the outlet orifice of the device, via a recess in the cap, in order to evacuate axially from above (then typically laterally, via the outlet orifice) the gases treated in the separation chamber.
- the cyclone comprises a flange delimiting the top of the upper separation chamber, the chimney protruding downwards into the separation chamber, from the flange, in order to present an annular external deflection surface at the same height level as the side intake inlet to deflect raw gases to the conical wall.
- An upper opening of the chimney, preferably axial, is provided to allow the gases treated in the separation chamber to escape towards the outlet orifice.
- the removable plug comes in two parts in the closed position.
- the plug has a first prehensible part placed outside the filling enclosure, and a second part penetrating inside the oil filling enclosure, making it possible to make integral with the plug at least the chimney of the cyclone, and having a transverse orifice through which a zone for the circulation of treated gases coming from the chimney communicates with the outlet orifice.
- A hollow interior space of the stopper, delimited between a gripping part of the stopper and the flange, typically forms a zone for the circulation of the treated gases which opens laterally towards the outside at the level of the outlet orifice.
- the outlet port is formed laterally in the upper end, the plug having an insertion part for sealingly connecting against the upper end, by using an annular sealing zone located lower than the exit hole.
- the annular sealing zone is produced by a sealing joint of the insertion portion, in radial contact against a cylindrical surface of the upper end.
- the cap can be inserted into the filling enclosure by screwing.
- the plug is in the functional position in an inserted state and locked by a bayonet type system (for example with a quarter turn).
- the separation device comprises a pressure regulating valve, movable at a distance from the chimney, placed in a hollowing out of the stopper extending axially between said first gripping part and the chimney.

- the pressure regulating valve is optionally in the form of a flexible membrane.

- the pressure regulating valve bears in a sealed manner against a seat, typically rigid and of annular shape (the seat possibly surrounding the central axis).
- the second part of the plug comprises at least one peripheral sealing element in contact with the oil filling chamber and separating in a sealed manner an upstream zone in communication with the inlet of the device and a downstream zone in communication with the exit hole.
- the oil filling enclosure has on the side of said upper end an internal annular rim extending perpendicularly to the central axis, said peripheral sealing element comprising at least one annular collar resting in a leaktight manner on the flange.
- The peripheral sealing element is in the form of an annular seal mounted for example in a peripheral annular groove of the cap.
- the downstream zone is located at the level of the upper end of the oil filling enclosure, the cyclone being made integral in rotation with the plug and able to move in vertical translation with respect to the plug between a position distant from the plug, in which only the downstream zone communicates with the outlet orifice, and a position close to the plug, in which the crankcase gases present in the oil filling enclosure can be evacuated through the outlet orifice without passing through the media filtering.
- the plug internally comprises a flexible membrane placed either in a first position in which it allows communication between the inlet orifice and the outlet orifice, or in a second position in which it prevents communication between the orifice of inlet and outlet orifice.
- the cap further comprises a vent hole for subjecting a first face of the flexible membrane to atmospheric pressure.
- The cyclone is integral with an oil collector, for example made in the form of an oil return duct located in the extension lower/lower than the conical portion of the cyclone.
- the oil collector comprises an elastically deformable member making it possible to purge the collected oil.
- the oil filler chamber is formed by the cylinder head block and the cylinder head cover of the engine.
- the oil filling enclosure is made by a tubular conduit.
- an oil coalescer filtration media, optionally pleated, is arranged upstream of the side intake inlet to be crossed and/or skirted by the raw flow of crankcase gases and allow the formation of droplets of increased size before passing through the separation chamber.

According to one feature, the conical wall of the cyclone constitutes all or part of a wall delimiting the oil filling enclosure on the outside, so that the plug is separable from the conical wall.

According to another feature, the cyclone constitutes a separation element maintained completely in an interior volume of the oil filling enclosure when the plug closes off the oil filling opening.

According to one option, the conical wall, offset radially inwards with respect to an internal face of the oil filling chamber, is secured to the cap by means of a flange delimiting the top of the filling chamber. superior separation.

Optionally, the device comprises a partition, which preferably extends upwards from the lower end, this partition separating two ducts which converge towards a common pipe for the gravity flow of oil where the lower outlet is provided, the two ducts including:
- a first conduit for the flow of separated oil into the separation chamber; and
- a second conduit in derivation or on the periphery with respect to the first conduit in the closure configuration of the plug, and which provides all or part of a passage section for circulating towards the outlet the fresh oil introduced by the filling opening, in a withdrawn/cap opening configuration (at the time of filling).

According to one option, the partition is tubular and delimits an upper part of the cyclone, extending from the lower end to the upper flange of the cyclone.

According to another aspect, the invention aims to separate crankcase gases by integrating a filling enclosure just under the oil plug to separate the oil droplets from the mist coming from the crankcase.

More particularly, a cyclonic separation method is proposed for separating elements in suspension in a gas issuing from an internal combustion engine crankcase, in a separation chamber provided between a reception inlet and an outlet orifice for the evacuation of gases which have been treated in the separation chamber, the method comprising the steps consisting essentially of:
- placing a cyclone forming the separation chamber, in an oil filling enclosure, the filling enclosure comprising a tubular upper end extending around a central axis, a lower end, and a passage for communication with the engine crankcase forming said receiving inlet to receive raw gas from the crankcase,
- closing an oil filling opening for the lubrication of the cyclone engine, delimited by said upper end, by a removable plug, in a closing configuration in which the plug closes said upper end, the cyclone being provided so that the chamber separation is located under the cap in the closure configuration,
- carry out the cyclonic separation in the separation chamber,
- using a chimney of the cyclone in communication with the outlet orifice, in order to evacuate axially from above, during the cyclonic separation, gases treated in the separation chamber, and
- allow gravity flow of separated oil into the separation chamber and/or of fresh oil introduced through the filling opening, through a lower oil flow outlet provided in the lower end and in communication with the oil sump of said engine.

The figures of the drawings will now be briefly described.

Figure 1 is a schematic view in longitudinal section of the separation device according to a first embodiment according to the invention;

Figure 2 shows the removable part of the device of Figure 1, seen along the same longitudinal section.

Figure 3 is a view, similar to that of Figure 1, of a separation device according to a second embodiment in accordance with the invention, with a two-channel arrangement at the lower end;

FIG. 4 is a diagrammatic view in longitudinal section of a separation device according to a third embodiment in accordance with the invention, with a cyclone design entirely integral with the plug.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Below is a detailed description of several embodiments of the invention accompanied by examples and reference to the drawings. In the various figures, identical references indicate identical or similar elements.

With reference to FIGS. 1 to 4, the separation device 10 makes it possible to separate the liquid and optionally solid parts of certain materials produced by the internal combustion engine and which come directly from the crankcase.

Such a separation device 10 is placed in and/or can form part of an enclosure 1, 11 for filling oil. In the example of Figures 1 and 3, the enclosure 1 is in the form of a tubular pipe wall opening at an upper end 11a at the level of an opening 12 used to fill engine lubricating oil. In a non-limiting way, the separation device 10 can be placed, integrated in the cylinder head cover CC (as illustrated in FIG. 4) or in an oil filling column (as illustrated by FIGS. 1 to 4). The pipe wall forming the enclosure 1, 11 has an inlet 2 communicating, for example via an inlet pipe (not shown) with the casing (not shown) of the internal combustion engine. It is therefore from this inlet 2 that the untreated crankcase gases G arrive. The filling enclosure 1 has at its upper part or end 11a a central axis A corresponding for example to an axis of symmetry of the opening 12.

In the interior volume V or V' delimited by the pipe wall of the enclosure 1, 11, it is possible to extract crankcase gases from liquid and solid particles, in particular in a separation chamber 18 by centrifugation effect . For this, the gases to be treated are routed into the separation chamber 18 via a side inlet E.

Furthermore, a plug 20 makes it possible to close the opening 12 in a closing configuration. In an opening configuration of this cap 20, it is possible to fill oil (fresh oil), the enclosure 1, 11 channeling this oil to a lower outlet 7 of the separation device 10.

With reference to FIGS. 1, 2, 3 and 4, plug 20 may have a recess 20c to allow gases treated in separation chamber 18, formed under plug 20, to escape upwards from the separation chamber. separation towards the hollow 20c, before joining an outlet orifice S of the device 10 provided laterally in the upper end 11a.

A first embodiment of the separation device 10 will now be described in more detail, with reference to FIGS. 1 and 2.

In this embodiment, the body 5 of the cyclonic separator or cyclone 15 on the one hand, and the oil filling tube or enclosure 1 on the other hand, can optionally form a single and same part PT. The filling opening 12 is then an upper opening of this part PT, which here is substantially tubular. The cyclone 15 also comprises a flange 14 on which is formed a chimney 19 participating in evacuating the treated gases upwards, out of the separation chamber 18 delimited by the tubular body 5 . Chimney 19 projects downward into separation chamber 18, acting as a rotational guide for the gas circulation lines of the flow entering separation chamber 18.

The body 5 may include a conical wall 16 of the cyclone 15, extended at the bottom by a lower end 11b of the enclosure 1 of narrower section than the upper end 11a delimiting the opening 12 for oil filling. The lower outlet 7 is included in this lower end 11b. In less preferred variants, it is possible to form a body 5 without a conical wall, possibly with internal shoulders. However, a tapered wall 16 improves separation efficiency. Generally, it is preferred to use plastic for the part PT forming the body 5 of the cyclone 15.

The gases enter the separation chamber 18 tangentially, via a lateral admission inlet E. The tangential outlet through the body 5 may correspond to the end of a lateral duct 3. In the example of FIG. 1, the inlet 2 of the device 10 can be made at the end of the lateral duct 3 which is distal from the body 5.

Here, the cyclone 15 has a conical wall 16 whose cross section decreases towards the lower outlet 7, moving away from the upper end 11a, the separation chamber 18 being at least partly delimited by the conical wall 16 and a upper wall element. Typically the upper wall element is in the form of an upper flange 14 mounted integral with the cap 20. The chimney 19, for example consisting of a cylindrical structure aligned with/parallel to the central axis A, can be formed integrally with the flange 14, in a plastic material.

The hollow 20a of the plug 20 here corresponds to a cavity or recess provided between a first gripping part 22 of the plug 20 and a sealed contact end provided to be inserted into the enclosure 1. The sealed contact end, here provided with An annular seal J or similar sealing element mounted for example in a peripheral annular groove of the cap 20, can belong to a second part 23 called the insertion part of the cap 20.

In FIG. 2, one can thus see an annular seal J placed in a groove, close to a zone for fixing the flange 14 delimiting the top of the separation chamber 18. The insertion part 23 makes it possible to connect the plug (20) sealingly against an inner face, here forming a cylindrical bearing surface, of the upper end 11a. The annular sealing zone Z4 is located lower than the outlet orifice S, as clearly visible in figure 1.

More generally, such a sealing zone Z4 can be produced in different ways, possibly by locking a bayonet-type connection or by screwing, a thread 11f then being provided in the insertion part 23. The outlet orifice S can extend in an axial zone comprised between:
- a sealing zone Z3 defined by an annular contact cap 20 – free edge of the upper end 11a (higher zone, with optional use of an annular, flat or O-ring seal, or a sealing lip) ,
- and the sealing zone Z4 (lower zone).

It is understood that the separation device 10 is designed and arranged to allow the transfer of purified gases GP able to circulate towards the inlet of the air intake distributor: the device 10 thus has the role of reinjecting gases into the distributor of air intake, after cyclonic separation under cap 20.

The separation device 10 has, as clearly visible in particular in Figures 1 and 2, here a pressure regulation valve called PRV ("Pressure Regulation Valve") in the plug 20. This valve can be essentially formed of a flexible membrane 41 which has an outer edge wedged or fixed in leaktight manner to the stopper 20, so as to separate a downstream zone Z2 from an interior volume 200 of the stopper 20 which is subjected to atmospheric pressure through a small orifice 42 for air formed in the gripping part 22 of the stopper 20. This venting orifice 42 is shown axial but can also be placed in a different way. The stopper 20 is for example provided with a circular groove or throat in which the outer edge of the flexible membrane 41 is housed.

This type of integration, optional, is illustrated for different embodiments. Of course, the pressure regulation function can be carried out by following alternative embodiments or can possibly be eliminated, according to requirements.

In the example of the figures, the membrane 41 is biased by a spring 43 or elastic return member/similar biasing member, which rests on a wall of the bore 26 of the insertion part 23. The membrane 41 is thus prestressed by this spring 43. When the suction at the inlet increases (outlet orifice side S), the membrane 41 moves towards its seat 44. This movement then creates a pressure drop which makes it possible to limit the depression upstream of the membrane 41. Under normal operating conditions, the force of the spring 43 is determined so that the membrane 41 is kept at a distance from the outlet of a duct 45 adjacent to the adjacent bore 26. In the event of strong depression in the upstream zone Z1 where the gases G arrive, the spring 43 can be compressed in such a way that the membrane 41 covers the duct 45 (by contact against the seat 44 formed here by the upper edge of the duct 45) and separates the downstream zone Z2 into two sectors: one in depression on the side of the separation chamber 18 of the cyclone 15 and the other on the side of the outlet orifice S which is then no longer or almost no longer supplied with gas by the separation device 10. Regulation is obtained by the valve thus formed.

In variant embodiments, the gases are evacuated through the bore 26 which is in the form of an outlet channel opening out between the grippable part 22 of the stopper 20 and a collar forming the seal between the upstream zone Z1 and the zone downstream Z2 (it is possible to use the design of FIGS. 3 and 6A of document EP 2108790 with regard to the production of the stopper contact 20 – filling chamber 1).

Here, the lower outlet 7 is used both during the fresh oil filling phases and for a return of separated oil droplets. The lower end 11b shown in Figure 1 may also have a valve 35 to allow accumulation of lubricating liquid L (as illustrated in Figures 3 and 4). More generally, the lower outlet 7 can be designed as an orifice for the gravity flow of oil separated into the separation chamber 18 and/or of fresh oil introduced through the opening 12 for filling. Typically, the lower outlet 7 is located in a low point of the lower end 11b and communicates with the engine oil sump.

The gas path is as follows. The gases G (laden with oil mist) enter through conduit 3 to reach the side intake inlet E and circulate in a rotary manner around the central axis A in the separation chamber 18, here by rotating around the substantially cylindrical conduit of the chimney 19. The centrifugal force obtained allows a mechanical separation of the particles/droplets of oil in suspension in the flow of gas. The oil particles lose their speed due to the impacts/friction against the internal face of the body 5 of the cyclone 15, so as to fall towards the lower end 11b, here formed integrally with the body, joining the lower outlet 7. The lateral admission inlet E is typically tangential to promote these impacts/friction. If a valve 35 is installed (as in FIG. 3 for example), then a lubrication liquid accumulation zone L is delimited in a part, preferably a narrow part, of the lower end 11b.

The narrowing of the lower end 11b results here from the conical wall 16 formed in the body 5 and delimiting the separation chamber 18. As regards the gaseous elements, these also follow the wall of the body 5 in the direction / up to 'in the vicinity of the apex, and once rid of the oil droplets, they rise towards the flange 14 to exit through the axial opening of the chimney 19.

The purified flow exiting through the chimney 19 then circulates in the downstream zone Z2, optionally on one side of the flexible membrane 41 of the pressure regulation valve. In the hollow 20a of the cap 20, there is typically an inverted U-shaped circulation, so that the purified gas passes into the conduit 45, an elbow being formed at the bottom of this conduit 45 for the lateral connection with the outlet orifice S The method of fixing the stopper 20 can allow the final locked position of the stopper 20 to coincide with an alignment between the outlet orifice S and the bore 26 of the insertion part 23.

Referring to Figures 1 and 3, it is possible to provide an oil collector 33 placed under the separation chamber 18 and supplied via a central opening 34 (case of Figure 1) or an opening offset with respect to the axis A (case of Figure 3) of the lower flange 18. The arrow H in Figure 3 illustrates the fall of the oil droplets into this collector 33 placed opposite the grippable obturating part 22 of the plug 20.

A manifold bleed opening 33 may correspond to the lower outlet 7, this opening being closed off by the valve 35 in one option as illustrated in FIG. 3. An elastic element may constitute such a valve. During engine operation, the pressure difference keeps the elastic element or the valve 35 against the seat, manifold side 33. When the engine stops, the pressures equalize and, under the weight of the oil L or lubricating liquid contained in the manifold 33, the resilient member moves away from the seating surface of the manifold 33, allowing oil to flow to the engine oil pan. The elastic element constituting the valve 35 may consist for example of a leaf spring or a similar elastic return member.

A second embodiment of the separation device 10 will now be described with reference to FIG. 3. The separation device 10 of FIG. 3 has many similarities with that of FIG. described.

Firstly, we can see a plug 20 which can also act as a shutter for a flow path or conduit C2 for fresh oil introduced via the filler opening 12. For this, the plug 20 may have an extension, for example in the form of a rod T reaching the level of the apex or similar zone of access to a passage provided in the lower end 19b. The rod T is for example connected by a spacer element or by a perforated plate to the conduit of the chimney 19. A snap-fastening of the rod T, here via an elastically deformable head 29 forming a clip, can allow a rigid connection of the rod T, which extends vertically, parallel to the central axis A. The chimney 19 is here arranged plumb with the closure part 22 of the cap 20, as well as the rod T, so that the conduit C2 is directly above the filling opening 12.

The filling enclosure 12 can be completely similar to that shown in figure 1, with the exception of the presence of a partition 8 between the collector 33 and a more direct oil return pipe.

Collector 33 may include or be made in the form of a first conduit C1, separate from conduit C2. In this particular embodiment, the channel or first duct C1 for collecting the oil from the oil mist is separated from the second duct C2 by a partition 8, for example formed integrally with the body 5 of the cyclone or attached to that -this. The partition 8 can thus separate two ducts C1, C2 which converge towards a common pipe C7 for the gravity flow of oil. The lower outlet 7 is here provided in this common pipe C7, forming a common outlet.

In the closure configuration of the cap 20, the opening 34 remains accessible to allow filling of the collector 33 in operation, with a flow in the first conduit C1, the liquid L accumulating in the closed state of the valve 35 The second duct C2 which defines the oil filling channel is closed in the oil separator operating mode, due to the position taken by the rod T. An annular sealing element 28 can be attached to the rod T, near or at the lower end of the latter, to achieve a radial sealed annular contact against an internal face of the first duct C1, as clearly visible in Figure 3.

Of course, the second duct C2 is accessible when the plug 20 is removed, since the chimney 19 and the rod T are integral with the plug 20. More generally, it is understood that the filling enclosure 1 can have a partitioning, in order to form :
- a first conduit C1 for the gravity flow of separated oil in the separation chamber 18; and
- a second conduit C2 in derivation or on the periphery with respect to the first conduit C1 in the closure configuration of the cap 20, and which provides all or part of a passage section for circulating, towards the outlet 7, fresh oil introduced through the filling opening 12.

A third embodiment of the separation device 10 will now be described with reference to FIG. 4. The separation device 10 of FIG. 4 has similarities with that of FIG. a hollow 20a above an on-board chimney 19 and the formation of a lower outlet 7 in a narrow lower end 11b of the filling enclosure 11.

Here to summarize, the cyclone 15 is of the type that can be dismantled and extracted with the stopper 20. Thus, the body of the cyclone 15 and the flange 14 including the chimney 19 are assembled with the insertion part 23 of the stopper 20. With this arrangement, the enclosure 11 is formed as a filling tube, one inner face of which faces an outer face of the tubular body of the cyclone 15. The upper end 11a of the filling enclosure 11 is identical to that illustrated in the figure , with an outlet orifice S provided facing a bore 26 formed in the stopper 20. However, this upper end 11a is no longer in the (upper) extension of the body 5 of the cyclone 15 but separated/shifted radially towards the outside with respect to the cyclone 15. The sealed connection of the stopper 20 is made in a similar way against the upper end 11a, by using an annular sealing zone Z4 located lower than the outlet orifice S.

With the cyclone 15 thus fixed under the stopper 20, via the flange 14, it is possible optionally to remove all at once, in one piece: the stopper 20, the cyclone 15 and optionally the collector 13 assembled to the body of the cyclone 15 by the underside. During oil filling, the filling enclosure 11 is then devoid of cyclone body in the interior volume V′ which constitutes a fresh oil spillage zone, contrary to the embodiments described above.

When the plug 20 closes the oil filling opening 12, the cyclone 15 constitutes a separating element maintained completely in the interior volume V′ of the enclosure 11, below the level of the opening 12. The conical wall 16 can form a free end of the insertion part 23 of the cap 20. Alternatively, the conical wall 16 can extend axially between a cylindrical portion where the lateral admission inlet E is formed and a receptacle forming the manifold 33.

The separation chamber 18 may consist of a cylindrical-conical cavity, optionally delimited by a body of the same general shape as in the preceding examples, with an opening 34 at the bottom of the cone (at the level of the apex) for the evacuation of drops of oil and an upper central opening in the chimney 19 for the evacuation of the clean gases GP.

As illustrated in FIG. 4, the conical wall or separation cone communicates with a lower chamber of the collector 33 where the drops of oil/lubricant L accumulate. This chamber of the collector 33, axial and plumb with the chimney 19 and cap 20, communicates with a lower filling tube via a flap or valve 35. Collector 33 is wider than the duct or pipe constituting chimney 19. The lower tube is here made in the form of a pipe common pipe C7, of vertical extension, and formed narrower than the large filling tube of the enclosure 11. On the top or at the inlet mouth of the common pipe 7, there is provided a compartment or a zone of convergence/junction CJ between duct C1 delimiting manifold 33 and duct C2 of annular section formed between large tube GT of filling enclosure 11 and tubular wall component 25 connected to flange 14.

The operation of the regulating valve with flexible membrane 41, of the valve 35 and the circulation of the gases are not further described here, given the complete similarity of operation with previously described embodiments. The gases G to be treated can pass through the top of the duct C2 between their exit from the duct 3 forming the inlet 2 and the access or lateral admission inlet E, typically by already adopting a tangential circulation.

One of the advantages of the invention is to provide effective separation of the crankcase gases as close as possible to the engine, with a reduced size of the separation device 10 since the separation is carried out in the oil filling line which is an already existing element.

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

Thus, although an example of collector 33 has been illustrated, formed in the extension of the cyclone body, such a collector 33 can be formed:
- integral with the lower end 11b, as a separate part of the part PT forming the separation cavity 18, when the cyclone 15 is a stationary part of the separation device 10,
and or
- stationary and included in the enclosure 1, 11, when the cyclone 15 withdraws with the stopper 20.

Claims (15)

Device (10) for separating elements in suspension in a gas from an internal combustion engine crankcase, comprising:
- an oil filling enclosure (1; 11) comprising an upper end (11a), a lower end (11b), and a passage communicating with the engine casing forming an inlet (2) of the device (10),
- a plug (20) removable to seal said upper end (11a), said upper end (11a) being tubular extending around a central axis (A) to form an opening (12) for filling oil for the engine lubrication when the plug (20) is removed,
- a separation chamber (18) placed under the plug (20),
- an outlet orifice (S) for the evacuation of gases which have been treated in the separation chamber (18), and
- a lower outlet (7) for the gravity flow of oil separated in the separation chamber (18) and/or of fresh oil introduced through the opening (12) for filling, the lower outlet (7) being located in the lower end (11b) and in communication with the oil sump of said engine,
characterized in that it further comprises a cyclone (15) forming said separation chamber (18) and provided with a chimney (19), in communication with the outlet orifice (S), for the axial evacuation by the top of the treated gases in the separation chamber (18). Separation device according to claim 1, in which the chimney (19) is integral with the plug (20),
and in which the chimney (19) is arranged plumb with a closing part of the plug (20), parallel to the central axis (A). Separation device according to claim 1 or 2, in which the cyclone (15) comprises:
- a conical wall (16) whose cross section decreases towards the lower outlet (7) away from the upper end (11a), the separation chamber (18) being at least partly delimited by the conical wall ( 16),
- a lateral admission inlet (E), preferably tangential, for passing raw gases from the inlet (2) of the device into the separation chamber (18); and
- said chimney (19), in communication with the outlet orifice (S), which extends parallel to and is crossed by the central axis (A). Separation device according to Claim 3, in which the cyclone (15) comprises a flange (14) delimiting the top of the upper separation chamber (18), the chimney (19) projecting downwards into the separation chamber ( 18), from the flange (14), in order to present an annular outer surface of deflection at the same level of height as the lateral admission inlet (E) to deflect the raw gases towards the conical wall (16). Separating device according to any of the preceding claims, wherein the outlet port (S) is formed laterally in the upper end (11a), the plug (20) having an insertion part (23) for connect in a sealed manner against the upper end (11a), by using an annular sealing zone (Z4) located lower than the outlet orifice (S). Separation device according to Claim 3 alone or in combination with one of Claims 4 and 5, in which the conical wall (16) of the cyclone (15) constitutes all or part of a wall delimiting the filling enclosure (1) on the outside. of oil, so that the plug (20) is separable from the conical wall (16). Separation device according to any one of Claims 1 to 5, in which the cyclone (15) constitutes a separation element maintained completely in an interior volume (V') of the enclosure (11) for filling oil when the plug (20) closes off the oil filler opening (12). Separating device according to Claim 7, in which the conical wall (16), offset radially inwards with respect to an internal face of the enclosure (11) for filling oil, is secured to the plug (20) via a flange (14) delimiting the top of the upper separation chamber (18). Separation device according to any one of the preceding claims, in which the removable plug (20) is in two parts in the closed position:
- a first grippable part (22) placed outside the filling enclosure (1; 11); and
- a second part (23) penetrating inside the oil filling enclosure (1, 11), making it possible to make integral with the stopper (20) at least the chimney (19) of the cyclone (15), and having a transverse orifice (26) through which a treated gas circulation zone from the stack (19) communicates with the outlet orifice (S). Separation device according to Claim 9, in which the separation device (10) comprises a pressure regulating valve, movable at a distance from the chimney (19) and preferably in the form of a flexible membrane (41), placed in a recess (20a) of the plug (20) extending axially between said first grippable part (22) and the chimney (19). Separation device according to Claim 9 or 10, in which the second part (23) of the stopper (20) comprises at least one peripheral sealing element (J) in contact with the enclosure (1; 11) for filling oil and sealingly separating an upstream zone (Z1) in communication with the inlet (2) of the device (10) and a downstream zone (Z2) in communication with the outlet orifice (S). Device according to Claim 11, in which the downstream zone (Z2) is located at the level of the upper end (11a) of the enclosure (1, 11) for filling oil, the cyclone (15) being made integral in rotation of the plug (20) and able to move in vertical translation relative to the plug (20) between a position remote from the plug (20), in which only the downstream zone (Z2) communicates with the outlet orifice (S), and a position close to the plug (20), in which the crankcase gases present in the enclosure (1, 11) for filling the oil can be evacuated through the outlet orifice (S) without passing through the filter medium (16 ). Device according to one of Claims 1 to 12, in which the stopper (20) comprises internally a flexible membrane (41) placed either in a first position in which it allows communication between the inlet orifice (2) and the orifice outlet (S), or in a second position in which it prevents communication between the inlet orifice (2) and the outlet orifice (S), the plug (20) further comprising an outlet orifice air (42) to subject a first face of the flexible membrane (41) to atmospheric pressure. Device according to one of Claims 1 to 13, comprising a partition (8) separating two ducts (C1, C2) which converge towards a common pipe (C7) for the gravity flow of oil where the lower outlet (7) is provided, the two pipes comprising:
- a first conduit (C1) for the gravity flow of separated oil in the separation chamber (18); and
- a second duct (C2) in derivation or on the periphery with respect to the first duct (C1) in the closure configuration of the plug (20), and which provides all or part of a passage section to circulate towards the outlet (7) fresh oil introduced through the filler opening (12) in an opening configuration of the cap (20). Cyclonic separation process for separating elements in suspension in a gas issuing from an internal combustion engine crankcase, in a separation chamber (18) provided between a reception inlet (2) and an outlet orifice (S) for evacuating gases which have been treated in the separation chamber (18), the method comprising the steps consisting essentially of:
- placing a cyclone (15) forming the separation chamber (18) in an oil filling enclosure (1; 11), the filling enclosure comprising a tubular upper end (11a) extending around a central axis (A), a lower end (11b), and a passage communicating with the engine casing forming said reception inlet (2) to receive raw gas from the casing,
- closing an oil filling opening (12) for lubricating the cyclone engine (15), delimited by said upper end (11b), by a removable plug (20), in a closing configuration in which the plug ( 20) closes said upper end (11a), the cyclone (15) being provided so that the separation chamber (18) is located under the stopper (20) in the closed configuration,
- carry out the cyclonic separation in the separation chamber (18),
- using a chimney (19) of the cyclone (15) in communication with the outlet orifice (S), in order to evacuate axially from above, during the cyclonic separation, gases treated in the separation chamber (18), and
- allowing a gravity flow of oil separated in the separation chamber (18) and/or of fresh oil introduced through the filling opening (12), through a lower oil flow outlet (7) provided in the lower end (11b) and in communication with the oil sump of said engine.