EP2018467B1 - Cyclone with a deflecting element as a separator in the crankcase ventilation system of an internal combustion engine - Google Patents

Abstract

The invention relates to an oil separator for removing oil from crankcase ventilation gases of an internal combustion engine, wherein the oil separator comprises at least one cyclone (1) which has a gas inlet (2), wherein the cyclone (1) is assigned a cover (3) in which is arranged a gas outlet (4, 6), and wherein the cyclone (1) is assigned a deflecting element (9, 19, 24, 29, 32, 33) in its interior (7). The oil separator according to the invention is characterized in that the deflecting element (9, 19, 24, 29, 32, 33) is formed, as viewed in the peripheral direction of the cyclone (1), with varying longitudinal extents with respect to the cover (3).

Description

The invention relates to an oil separator for de-oiling crankcase ventilation gases of an internal combustion engine, wherein the oil separator comprises at least one cyclone having a gas inlet, wherein the cyclone is associated with a lid in which a gas outlet is arranged, and wherein the cyclone in its interior Is assigned rejection element.

The EP 1 095 209 B1 shows a Ötabscheider for de-oiling of crankcase ventilation gases of an internal combustion engine, wherein the oil separator comprises at least one cyclone having a gas inlet connected to the crankcase of the internal combustion engine, a gas outlet connected to the air intake tract of the internal combustion engine and an oil outlet connected to the oil sump of the internal combustion engine. The gas outlet protrudes as a dip tube through a top closing the cyclone in the cyclone interior. Above the gas outlet, a gas line section is provided above the cover with a jumped to at least twice the enlarged cross-section. From the gas line section there is ansammeindes oil traceable to the oil outlet or to the oil sump. The dip tube ends just above the lid. From the top of the lid, starting from the gas line section, an oil discharge channel is led separately from the dip tube to the oil outlet or to the oil sump.

In the DE 100 65 328 A1 discloses a gas-liquid separator having a generally cylindrical container internally defining a cyclone chamber and having a gas inlet opening on an inner peripheral wall of the cyclone chamber for introducing a gas into the cyclone chamber in a circumferential direction of the cyclone chamber for separation a liquid component from the gas by a centrifugal separation action, with a gas passageway having a gas outlet connected to the cyclone chamber via the gas outlet, the gas outlet being disposed separately from the gas inlet in the axial direction of the container, and a baffle disposed in the cyclone chamber and a space between the gas outlet and the gas inlet generally divides to form a gas flow which flows from the gas inlet to the gas outlet along the inner peripheral wall, wherein the gas passage line protrudes from the baffle at the gas inlet opposite side.

The DE 43 44 507 A1 deals with a cyclone for the separation of oil from oil-containing aerosols. In the interior of the cyclone extends an exhaust pipe. The exhaust port is flared from its lower inlet end to its upper outlet end. The exhaust pipe is enclosed near its inlet end by a hollow frustum-shaped Abweisring whose larger diameter faces the inlet end.

Cyclones as oil scrapers are known in the crankcase ventilation area. Depending on the application (eg petrol or diesel engine, type of ventilation system), depending on the design, the cyclones fulfill the requirement to reduce the oil content in the blow-by gas (crankcase ventilation gas). In fine oil cyclones, the geometry is designed and designed in such a way that effectively finest oil mist droplets (fine oil: x _tropfan <10 microns) are deposited. For this purpose, the cyclone or the cyclone size with respect to the differential pressure behavior is adapted to the operating conditions of the engine, in particular its blow-by map, adjusted so that sufficiently wide cyclone differential pressures prevail over wide engine operating ranges for effective fine oil separation.

In the case of high engine oil ejection quantities, eg in the form of coarse oil (coarse oil: x _drops > 10 μm, visible oil components in spatter form or creep oil form), it may be necessary to use coarse oil separators in addition to the fine oil separator (fine oil cyclone or other fine oil separator types, eg textile separators). These are usually integrated on the crankcase side of the fine oil separator in the venting systems. Possibly. can be dispensed with a Feinölabscheider at low fine oil ejection amounts, so that the oil separation (protection against Ölmitreißen in the intake system) is ensured only by the coarse oil. In order not to detune the pressure balance of the engine or the internal combustion engine, these are Coarse oil separators adapted to your specific task by the geometry. As a rule, the differential pressures are below the values for the fine oil separators.

As coarse oil separators also offer cyclones. Conventional simple-dip-tube cyclones, however, show weaknesses in the deposition, especially when coarse oil in the form of entrained drops and splashes occurs. Drops that hit the dip tube, run down and are then partially transported from the lower edge of the dip tube in the dip tube inside up to the clean side. In some cases, smaller coarse oil droplets (10 μm <x _drops <50 μm) are not separated off at the required low differential pressure design of coarse oil cyclones, but are transported undesirably directly to the clean side.

In order to avoid the entrainment of oil components of the Tauchrohraußenwand inside, so-called baffles or deflector rings are used around the dip tube, such. B. in the DE 100 65 328 A1 and in the DE 43 44 507 A1 executed. However, these embodiments do not show the desired effect for the requirements in the crankcase ventilation area.

Based on the requirements in the crankcase ventilation area, the known measures for avoiding the oil pressure rupture by the cyclone are not a suitable solution. The time of oil leakage is delayed at most. Coarse oil is not safely separated over longer periods of time (normal driving). Oil deposits that have already been separated are squirted by the vortex flow. These drops are then transported by the flow on to the clean side. At 45 ° pitch of the cyclone, conventional baffles or deflector rings do not perform the desired function.

Entrained oil components can in principle be recycled by so-called pure-side oil drain holes from the dip tube clean side to the cyclone oil drain, as comprising in the EP 1 095 209 is shown what has proven in practice quite well. However, this existing solution must be adapted to the relatively high coarse oil volumes and means in a standard implementation of a correspondingly increased technical effort and space requirements and thus additional costs.

The invention has for its object to improve an oil separator of the type mentioned in that its Abscheidewirkung is improved, at the same time a simple and inexpensive oil separator should be provided.

• dass das Abweiseelement mit dem Deckel verbunden oder einstückig ist und sich von dem Deckel in Richtung zu einem dem Deckel gegenüberliegenden konusförmigen Bereich des Zyklons erstreckt,
• dass das Abwelseelement als Hohlzylinder in Umfangsrichtung des Zyklons gesehen bezogen auf den Deckel mit variierenden Längserstreckungen ausgeführt ist und
• dass das Abweiseelement zwischen einer Außenwand des Zyklons und einer gedachten Verlängerung des Gasauslasses in den Zyklon hinein oder zwischen der Außenwand des Zyklons und einem in das Innere des Zyktons hineinragenden Tauchrohr angeordnet ist.

The solution of this object is achieved according to the invention by an oil separator of the type mentioned, which is characterized

• that the rejection element is connected to the lid or is integral and extends from the lid towards a cone-shaped area of the cyclone opposite the lid,
• that the Abwelseelement is designed as a hollow cylinder in the circumferential direction of the cyclone with respect to the lid with varying longitudinal extent and is executed
• the rejection element is arranged between an outer wall of the cyclone and an imaginary extension of the gas outlet into the cyclone or between the outer wall of the cyclone and a dip tube projecting into the interior of the cyclone.

In the case of the oil separator according to the invention, a 100% oil separation efficiency, for example of creeping oil and spray oil, is achieved with the special geometric configuration of the rejection element. The oil separator can be used both as a coarse oil separator and as a fine oil separator. In this case, the gas outlet in the cover can be designed as a dip tube, which protrudes into the interior of the cyclone. Alternatively, the gas outlet can also be embodied as a simple conduit, which is introduced only into the lid and preferably terminates flush with the underside of the lid, ie does not protrude into the interior of the cyclone.

Favorable in the context of the invention is when the rejection element has a free edge, which is designed with respect to the cover in the circumferential direction of the cyclone with varying lengths or heights.

It is expedient for the purposes of the invention if the rejection element is arranged to run concentrically around the center axis in the interior of the cyclone, so that the deflecting element is arranged in a quasi-cylindrical manner in a cross section through the cyclone. Of course, every geometric design is conceivable the Abweiselements, for example, a square-shaped in cross-section design or the like.

In a first advantageous embodiment, the gas inlet in the upper region of the cyclone, so arranged near the lid.

Furthermore, it is preferably provided that the gas outlet is arranged concentrically around a central axis of the cyclone.

Favorable for the purposes of the invention is when the rejection element has a course at its free edge which resembles a cylinder cut off askew.

In this case, advantageously, the rejection element based on the lid a minimum height (hs _min ) and a maximum height (hs _max ), which are arranged diametrically opposite relative to the central axis of the cyclone. In this embodiment, the drops deposited on the rejection element run off at its outer wall as far as the free edge. Drops adhering to the free edge are conveyed by the vortex flow to the deepest point of the rejection element (hs _max ), so that the oil drops drip at this point in a targeted and continuous manner. The maximum height (hs _max ), ie the lowest point of the rejection element, can be determined or varied, in particular in its position relative to the gas inlet in the interior of the cyclone, depending on the application. The targeted dripping at a defined location relative to the position of the gas inlet is desirable in order to prevent subsequent entrainment of the squirting droplets through the flow in the gas outlet or in the dip tube and thus on the cyclone clean. Therefore, the rejection element advantageously has the special geometric design or manner of length increase in coordination with the prevailing vortex flow formation and thus the cyclone geometry.

In a further advantageous embodiment, the rejection element has at least one drip edge, the rejection element having a minimum height and a maximum height relative to the lid, which are arranged one above the other as viewed in the vertical direction. In this embodiment, the height or longitudinal extent of the rejection element abruptly decreases at one point. The rejection element expediently has a minimum height (hs _min ) and a maximum height (hs _max ), which are arranged one above the other when viewed in the vertical direction. The free edge preferably runs helically or spirally from the minimum height (hs _min ) in the direction of the maximum height (hs _max ). Between both, ie the minimum height (hs _min ) and the maximum height (hs _max ), the free edge runs perpendicularly, ie parallel to the central axis, so that the free edge arranged in this region forms a discharge edge. By means of this advantageous embodiment, the targeted dripping is further improved.

In a further preferred embodiment, the rejection element may have two drip edges, which are arranged diametrically opposite relative to the central axis of the cyclone.

In this embodiment, the deflector element advantageously has two circular section-like wall sections lying diametrically opposite the central axis whose minimum height (hs _min ) and maximum height (hs _max ) are each arranged on one plane, the respective minimum height (hs _min ) corresponding to the respective maximum height (hs _max ) decreases abruptly, thereby forming the desired trailing edge.

The free edge extending between the respective wall sections in this case preferably runs continuously inclined from the respective minimum height (hs _min ) to the respective maximum height (hs _max ), wherein the diametrically opposite, continuously inclined free edges are inclined in opposite directions.

In a further preferred embodiment, the rejection element has a plurality of drip edges, so that virtually a sawtooth-like course of the frelian edge with the trailing edge is formed. Also here, the respective minimum height (hs _min ) increases to the respective maximum height (hs _max ) to form the abruptly.

In the advantageous embodiments described above, the rejection element is arranged quasi as a hollow cylinder between an outer wall of the cyclone and an imaginary extension of the gas outlet into the cyclone or between the outer wall of the cyclone and the immersion tube protruding into the interior of the cyclone and connected to the cover. The respective different embodiments can be advantageously produced by means of simple tools as plastic injection molded parts.

The gas inlet can not only be made round, but have all suitable geometrical configurations. For example, the gas inlet can be made square.

Overall, with the different configurations and arrangements of the rejection element, an improved oil separation effect, in particular in the case of coarse oil in the form of entrained drops and splashes, is achieved even with an inclined position of the oil separator. It also improves the Feinölabscheidewirkung. The respective rejection element with its varying length can be used with appropriate adaptation advantageous in different cyclone designs to reduce Ölmitreißneigung. For example, an application in parallel cyclones is conceivable.

Oil recirculation of the separated oil may e.g. via a siphon or by way of example via an oil sump with oil return valve.

Fig. 1

einen Zyklon mit einem Abweiseelement In einer perspektivischen An- sicht,

Fig. 2

den Zyklon aus Figur 1 mit einer zweiten Ausführung des Abweiseele- ments,

Fig. 3

den Zyklon aus Figur 1 mit einer dritten Ausführung des Abweiseele- ments und

Fig. 4

den Zyklon aus Figur 1 mit einer vierten Ausführung des Abweiseele- ments.

Embodiments of the invention are explained below with reference to a drawing. Show it:

Fig. 1

a cyclone with a rejection element In a perspective view,

Fig. 2

the cyclone FIG. 1 with a second embodiment of the rejection element,

Fig. 3

the cyclone FIG. 1 with a third embodiment of the rejection element and

Fig. 4

the cyclone FIG. 1 with a fourth embodiment of the rejection element.

In the different figures, the same parts are always provided with the same reference numerals, which is why these are usually described only once.

FIG. 1 shows a cyclone 1 of an oil separator for de-oiling of crankcase ventilation gases (blow-by-gas) of an internal combustion engine. The cyclone 1 has a gas inlet 2, wherein the cyclone 1, a lid 3 is associated. In the lid 3, a gas outlet 4 is arranged, which in the in FIG. 1 illustrated embodiment as a dip tube 6 projects slightly into the interior 7 of the cyclone 1. The dip tube 6 or the gas outlet 4 is arranged concentrically around a central axis X of the cyclone 1 around. In the interior 7 of the cyclone 1, a rejection element 9 is arranged. The rejection element 9 is viewed in the circumferential direction of the cyclone 1 with respect to the cover 3 with varying longitudinal extent.

The cyclone 1 has a cylindrical portion 11, which is closed at the top by the cover 3, and a conical portion 12 which adjoins the cylindrical portion 11 at the bottom. The conical region 12 opens with its directed away from the cover 3 cone tip in an oil outlet 13th

The rejection element 9 has a free edge 16, which is designed with respect to the cover 3 in the circumferential direction of the cyclone 1 with varying lengths or heights.

The deflector 9 is arranged concentrically around the central axis X of the cyclone 1 between its wall and the dip tube 6 and has a quasi-hollow cylindrical configuration. In a preferred embodiment, the deflector 9 is connected to the lid 3, wherein a cohesive connection can be provided. But it is also possible a one-piece production of the lid 3 with the rejection element 9 and possibly with the dip tube 6 and the gas outlet. 4

With its lid 3 opposite free edge 16, the deflector 9 extends in the direction of the cone-shaped portion 12th

At its free edge 16, the rejection element 9 has a course which resembles a hollow cylinder cut off obliquely. Here, the rejection element 9 relative to the lid 3 advantageously has a minimum height hs _min (in the FIGS. 1 to 4 optionally designated by the reference numeral 17) and a maximum height hs _max (in the FIGS. 1 to 4 optionally designated by the reference numeral 18), which are arranged diametrically opposite relative to the central axis X of the cyclone 1. In this embodiment, the deposited on the rejection element 9 drops run on its outer wall to the free edge 16.

FIG. 2 shows a further embodiment of the Abweiselements 19, which has at least one drip edge 21. In this embodiment, the height or longitudinal extension of the Abweiselements 19 decreases abruptly at one point, so that a drain edge 23 is formed. In this case, the deflecting element 19 advantageously has a minimum height hs _min and a maximum height hs _max , which are arranged one above the other in the vertical direction. The free edge 16 preferably runs helically or spirally from the minimum height hs _min in the direction of the maximum height hs _max . Between both, ie the minimum height hs _min and the maximum height hs _max , the free edge 16 runs perpendicularly, ie parallel to the central axis X, so that the free edge 16 arranged in this region can be referred to as a discharge edge 23.

FIG. 3 shows a further embodiment of the Abweiselements 24, which has two Abtropfkanten 26, 27, which are arranged diametrically opposite relative to the central axis X of the cyclone 1. In this embodiment, the rejection element 24 has two circular section-like wall sections 28 diametrically opposite the central axis X whose maximum height hs _max and minimum height hs _{min are} each arranged on one plane, the respective minimum height hs _min abruptly decreasing at the respective maximum height hs _max to form the drainage edge 23. The running between the respective wall sections 28 free edge 16 in this case runs continuously inclined from the respective minimum height hs _min to the respective maximum height hs _max , wherein the diametrically opposite continuously inclined extending free edges 16 are inclined in opposite directions. In the embodiment according to FIG. 3 the dip tube 6 does not protrude into the cyclone 1 by way of example.

FIG. 4 shows a further embodiment of the Abweiselements 29, which has a plurality of Abtropfkanten 31, so that the rejection element 29 is carried out at its free edges 16 quasi sawtooth. Here, too, the respective minimum height hs _min abruptly decreases at the respective maximum height hs _max , in order to form one of the several trailing edges 31 in each case. Of course, the illustrated number of drip edges 31 is only exemplary and not intended to be limiting; it may also be provided more or less dripping edges 31.

The differently executed rejection elements 9, 19, 24 and 29 in the embodiments according to the FIGS. 1 to 4 are arranged as a hollow cylinder between an outer wall of the cyclone 1 and an imaginary extension of the gas outlet 4 into the cyclone 1 or between the outer wall of the cyclone 1 and the projecting into the interior 7 of the cyclone 1 dip tube 6 and connected to the lid 3.

Claims (12)

1. Oil separator for de-oiling crankcase ventilation gases of an internal combustion engine, wherein the oil separator comprises at least one cyclone (1) which has a gas inlet (2), wherein a cover (3) is allocated to the cyclone (1), a gas outlet (4) being arranged in said cover, and wherein a deflection element (9, 19, 24, 29) is allocated to the cyclone (1) in its interior (7),
   characterized in that

   - the deflection element (9, 19, 24, 29) is connected with the cover (3) or is of one piece with the cover (3) and extends from the cover (3) in the direction of a cone-shaped area (12) of the cyclone (1) opposite the cover (3),

   - the deflection element (9, 19, 24, 29) is designed as a hollow cylinder with, seen in the circumferential direction of the cyclone (1), varying longitudinal extensions relative to the cover (3), and

   - the deflection element (9, 19, 24, 29) is arranged between an outside wall of the cyclone (1) and an assumed extension of the gas outlet (4) into the cyclone (1) or between the outside wall of the cyclone (1) and an immersion tube (6) extending into the interior (7) of the cyclone (1).
2. Oil separator according to claim 1, characterized in that the deflection element (9, 19, 24, 29) has a free edge (16) which, seen in circumferential direction of the cyclone (1), is executed with varying lengths or heights, respectively, relative to the cover (3).
3. Oil separator according to claim 1 or 2, characterized in that the deflection element (9, 19, 24, 29) in the interior (7) of the cyclone (1) is arranged concentrically around a center axis (X) of the cyclone (1).
4. Oil separator according to claim 1, 2 or 3, characterized in that the gas outlet (4) is arranged concentrically around a center axis (X) of the cyclone (1).
5. Oil separator according to any one of the claims 1 to 4, characterized in that the deflection element (9), on its free edge (16), has a course which is similar to that of a cylinder cut off at an incline.
6. Oil separator according to any one of the claims 1 to 4, characterized in that the deflection element (9), relative to the cover (3), has a minimum height (hs_min) and a maximum height (hs_max) which are arranged diametrically opposed relative to the center axis (X) of the cyclone (1).
7. Oil separator according to any one of the claims 1 to 4, characterized in that the deflection element (19) has at least one drip-off edge (21), wherein the deflection element (19), relative to the cover (3), has a minimum height (hs_min) and a maximum height (hs_max) which are arranged one over the other seen in the direction of height.
8. Oil separator according to claim 7, characterized in that the free edge (16) extends in screw line form or spiral form from the minimum height in direction towards the maximum height, wherein the free edge (16) extends between both heights parallel with the center axis (X) so that a run-off edge (23) is formed.
9. Oil separator according to any one of the claims 1 to 4, characterized in that the deflection element (24) has two drip-off edges (26, 27) which, relative to a center axis (X) of the cyclone (1), are arranged diametrically opposed.
10. Oil separator according to claim 9, characterized in that the deflection element (24) has two wall sections (28) diametrically opposed to the center axis (X), said sections being designed in circular segments, whose minimum height (hs_min) and maximum height (hs_max) are each arranged on one level, wherein the corresponding minimum height abruptly decreases to the maximum height so that the free edge (16) is here formed as run-off edge (23).
11. Oil separator according to claim 10, characterized in that the free edge (16) extending between the corresponding wall sections (28) extends steadily inclined from the corresponding minimum height (hs_min) to the corresponding maximum height (hs_max).
12. Oil separator according to any one of the claims 1 to 4, characterized in that the deflection element (29) has a plurality of drip-off edges (31) so that, as it were, a saw-tooth like course of the free edge (16) with run-off edge (23) is formed.

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