EP2020485B1 - Oil mist separator of a combustion engine - Google Patents

Description

The invention relates to an oil mist separator of an internal combustion engine, according to the preamble of claim 1.

In internal combustion engines, especially in automotive engineering, it is necessary to clean crankcase ventilation gas from liquid contaminants, especially lubricating oil mist and droplets. For this purpose serve u.a. Centrifugal separators comprising a plate stack separator.

From the EP 1 273 335 B1 and from the WO 2006/132 577 A1 centrifugal separators are known with Tellerstapelseparator, wherein the rotor is radially outwardly surrounded by a housing and the rotor rotates relative to the stationary housing, so that radially outwardly carried oil impinges on a housing inner side and runs down.

Another Tellerstapelseparator is from the patent DE 103 38 770 B4 known, wherein a plurality of axially arranged plates form a rotor and rotate together and thus pressed due to the resulting centrifugal forces, for example, oil droplets to the outside. There they meet a substantially cylindrical gas guide ring, which surrounds the rotor radially on the outside. This basket is rotatably connected to the rotor, so that the basket rotates with the plates.

A disadvantage of these known Zentrifugalabscheidem has been found that the separation efficiency is not always sufficient.

Based on this prior art, the object of the present invention is to provide an oil mist separator of the type mentioned in the introduction, which has a simple structural design with improved separation efficiency.

The object is achieved according to the invention by a Ölnebelabscheider with the features of the preamble of claim 1, which is characterized in that an executed as a single part, a Prallabscheidefläche forming hollow cylindrical Gasleitring the rotor radially outwardly surrounding, extending in the axial direction of the rotor and relative to the rotor not co-rotating inserted into the housing.

In the oil mist separator according to the invention for internal combustion engines with a Tellerstapelseparator a rotor surrounding the outside gas guide ring is present, which is not co-rotating with the rotor. This means that the rotor rotates relative to the surrounding gas guide ring. The gas guide ring forms a Prallabscheidefläche and may be formed substantially hollow cylindrical. In known manner, the rotor is e.g. driven by a lubricating oil flow. Through the rotating stack of plates, the mixture of gas and oil mist receives a swirling movement and the oil is removed due to the centrifugal force to the outside and separated from the gas. Such a gas guide ring can be produced in a simple manner so that the desired functionalities are fulfilled. The gas guide ring may be formed fixed, for example, by being firmly connected to the surrounding housing of the centrifugal separator, or it may also be designed to be movable relative to this housing, but it does not rotate with the rotor. The advantage of the invention is that the Ölnebelabscheider for internal combustion engines has a simple structure and is better deposited by the relative to the rotating rotor not co-rotating gas guide ring oil from the crankcase ventilation gas.

It is further provided that the gas guide ring is movable in the axial direction of the rotor relative to the rotor and the housing, wherein the cross section of a clean gas passage between the rotor and the gas guide ring is variable by this movement. Thus, a size-variable gap is formed between the gas guide ring and the rotor.

Preferably, it is further provided that the cross section of the clean gas passage can be changed in the sense that the gas is smaller in the case of a smaller clean gas volume flow, the cross section of the clean gas passage is smaller and the cross section of the clean gas passage is greater for a larger clean gas volume flow.

Preferably, the axial movement of the gas guide ring can be generated solely by a flow of the clean gas. If a slight overpressure prevails in the rotor, then the gas guide ring can be slightly raised in the axial direction by a gas flow flowing axially on the outside in order to increase the gap until a pressure equalization has been established. With decreasing volume flow, the gas guide ring automatically drops again and the gap size is reduced.

So that the gas flow can exert the necessary force on the gas guide ring, an upper edge is designed to be bent radially inwardly on this expediently. For the design of the gas guide this can at its upper edge, for example. Bent in an L-shape so as to redirect and direct the gas flow. Alternatively, this upper edge can also be formed cranked, that is, e.g. two 90 - have deflections. By such a groove-shaped edge in particular leakage of lubricating oil is prevented upwards in a clean gas outlet.

In order to ensure an automatic return of the gas guide ring, this is preferably acted upon by a biasing force which acts in the direction of a reduction of the cross section of the clean gas passage.

In this case, the force acting on the Gasleitring biasing force can be generated by gravity or by spring force.

To improve the separation performance, at least one oil drain trough is preferably formed on the inner peripheral side on or in the gas guide ring. Due to this oil drainage channel, the oil impinging on the gas guide ring due to the centrifugal forces is discharged downwards and can no longer be removed from the clean gas flow at the top.

Preferably, it is further proposed that the at least one Ölabelitrinne runs along at least one helical line, which points in the direction of rotation of the rotor facing down. The swirl of the gas flow thus supports the oil removal. In addition, the oil drain trough can support oil separation through impingement and flow deflection.

It is preferably provided that the at least one Ölabelitrinne is formed by a cross-sectionally L-shaped or U-shaped profile, with an open side of Ölabelitrinne facing down. In this form, the oil drain trough is stable and contributes to the stability of the gas guide ring. In addition, a favorable injection molding production in this design is possible. Inside this Ölabelitrinne the oil is largely protected against entrainment by the rotating gas flow.

In a simple embodiment, the gas guide ring can form a closed, perforation-free surface.

The gas guide ring may then be e.g. be formed by a one-piece hollow cylinder made of plastic or metal.

Alternatively, the gas guide ring may form a perforated or porous surface to receive oil therein.

For this purpose, the gas guide ring may be formed by a hollow-cylindrical lattice or sieve or filter material body.

For reasons of cost-effective mass production and good durability, the at least one Ölabelitrinne is advantageously molded onto the gas guide ring.

If the material of the Gasleitringes itself is less stable or non-bearing, then it is preferably provided that at least one support ring, preferably two axially spaced apart and circumferentially circumferential support rings, is molded onto the gas guide ring except the at least one Ölabelitrinne /.

In order to safely keep oil, which migrates upwards on the inner circumference of the gas guide ring, away from the clean gas flow and dissipate it in the desired manner downwards, it is proposed that a plurality be distributed over the inner circumference of the gas guide ring Ölableitrinnen are provided and that an upper edge of the Gasleitringes has radially inside oil scoop sections which are open axially downwards and extending between each two adjacent Ölableitrinnen in this or one of these passing.

In a further embodiment, it is proposed that the lattice or screen or filter material body forming the gas guide ring consists of a non-self-supporting element made of woven or knitted fabric or knitted or knitted fabric, preferably of textile material, or of open-cell foam, each with an integrated support body, or a self-supporting element of a woven or knitted fabric or scrim or knit, preferably of metallic material, or of sintered material.

For collecting and discharging the separated lubricating oil, it is favorable if the grid or sieve or filter body forming the gas guide ring has a mesh or pore size between 10 and 300 μm.

In order to allow oil to flow out not only through the porous body forming the gas guide ring but also radially outwardly therefrom, it is proposed that an oil discharge annulus be kept free between an outer circumferential surface of the gas guide ring and an inner circumferential surface of the housing.

In order to still possibly deposit in the clean gas outlet entrained oil particles, it is proposed that at the level of a gas outlet end of the Gasleitringes on an inner peripheral surface of the housing, a deflection ring is attached or formed, which points against a present gas flow direction in the interior of the housing. Due to the deflection ring, the gas flow is forced to a sharp deflection, which can not follow the oil particles. The oil particles catch rather radially outside of the deflection ring and can be discharged from there down.

In the embodiments of the oil mist separator described above, two separate annular spaces are formed in the housing between the inner peripheral surface of the housing and the rotor. On the one hand, this is a first annular space between the rotor and the gas guide ring, through which substantially the clean gas is discharged, which does not or hardly passes through the gas guide ring to the outside. On the other hand is formed between the gas guide ring and the surrounding inner peripheral surface of the housing, a second annular space through which the oil is discharged. Through the separation of these annular spaces it is achieved that in the second, outer annulus practically no gas flow is more, so that the oil can flow down there practically turbulence down.

To further reduce a gas flow in the second, outer annular space, a labyrinth seal can be formed between a housing wall of the separator and the gas guide ring, which substantially inhibits the passage of a gas flow, so that this second, outer annular space is kept free of turbulence.

Figur 1

einen Ölnebelabscheider mit einem nichtdrehenden Gasleitring, im Längsschnitt,

Figur 2

den Ölnebelabscheider aus Figur 1 in einer geänderten Ausführung, im Längsschnitt,

Figur 3

einen Gasleitring in Draufsicht,

Figur 4

den Gasleitring aus Figur 3 im Längsschnitt gemäß der Schnittlinie A - A in Figur 3,

Figur 5

den Gasleitring in einer weiteren Ausführung, im Längsschnitt,

Figur 6

den Gasleitring in einer geänderten Ausführung, im Längsschnitt, und

Figur 7

den Gasleitring in einer nochmals geänderten Ausführung, im Längsschnitt.

In the following, embodiments of the invention will be explained with reference to a drawing. Showing:

FIG. 1

an oil mist separator with a non-rotating gas guide ring, in longitudinal section,

FIG. 2

the oil mist separator off FIG. 1 in a modified version, in longitudinal section,

FIG. 3

a gas guide ring in plan view,

FIG. 4

the gas guide ring FIG. 3 in longitudinal section along the section line A - A in FIG. 3 .

FIG. 5

the gas guide ring in a further embodiment, in longitudinal section,

FIG. 6

the gas guide ring in a modified version, in longitudinal section, and

FIG. 7

the gas guide ring in a further modified embodiment, in longitudinal section.

In the FIGS. 1 and 2 In each case, an oil mist separator 1 of an internal combustion engine with a rotor 2 in the form of a stack of plates is shown, wherein a plurality of plates 20 form the rotor 2, which can be set in rotation by a rotary drive 23. Of the Rotor 2 is in this case arranged in a housing 10 of the oil mist separator 1. The stack of plates 20 is below and top side of a stacking pedestal 24 and a stacking cap 25 enclosed. A spring 26 presses the stacking attachment for fixing the plate 20 down. A shaft 21 carries the rotor 2 and is mounted in an upper bearing 22 and a lower bearing 22 '.

A base plate 16 bounds the housing 10 on the underside. With this underside of the oil mist separator 1 can be flanged as a unit with the interposition of seals 17 by means of screws 18 to an internal combustion engine. The shaft 21 passes through the base plate 16 down through and carries there the rotary drive 23rd

To be de-oiled crankcase ventilation gas is introduced from below into a space region 12, then flows radially inwardly from bottom to top in the rotor 2 and then between its plates 20 radially obliquely outward. In this case, entrained oil particles are deposited on the plates 20 as a result of centrifugal force action. The separated oil flows radially outwards on the underside of the plate and is thrown off radially outwards. The clean gas is discharged upward in a space area 13, to which, as shown in the examples, a crankcase pressure control valve 4 can connect. From there, the clean gas flows out through the gas outlet 40, e.g. to the intake manifold of an associated internal combustion engine.

In FIG. 1 the separator 1 has a surrounding gas surrounding the gas guide ring 3 wherein the gas guide ring 3 is formed such that it does not rotate with the rotor 2. He may either be arranged spatially fixed and, for example, be firmly connected to the housing 10 or he may be used loosely. In addition, the gas guide ring 3, as indicated by the double arrow, movable in the axial direction, so as to change an annular gap-shaped clean gas passage 32 between an upper edge 31 of the gas guide 3 and the radially outer edge of the plate top side covering stacking top 25.

If the pressure rises in the interior of the rotor 2, the gas guide ring 3 can be raised slightly by the flow pressure, so that the clean gas passage 32 increases until a pressure equalization is obtained. The provision of the gas guide 3 down is done by gravity. If necessary, for this purpose, the gas guide ring 3 can be acted upon by a spring force.

In this case, the upper edge 31 either as shown, bent L-shaped, or be cranked so as to form a groove, so that the leakage of lubricating oil is effectively prevented at this edge 31. By the relative to the rotor 2 fixed surface of the gas guide 3, the separation efficiency of the separator 1 is improved.

In addition, on the inner surface of the gas guide ring 6, there may be provided, preferably helical downwardly extending fins 33, for discharging the separated lubricating oil, as in FIG FIGS. 6 and 7 is shown.

In FIG. 2 the gas guide ring 3 is omitted or not yet installed. Different from FIG. 1 is that the housing 10 in FIG. 2 on the inside in the amount of the radially outer edge of the stacking cap 25 has a deflection ring 11 '. The deflection ring 11 'points downwards and forms a sharp flow deflection for the upwardly flowing gas flow, whereby any oil particles still contained in it are separated. These oil particles then flow downwards on the inner circumferential surface 11 of the housing 10.

The FIGS. 3 and 4 show a gas guide 3 as a single part in plan view and in longitudinal section. On the inner peripheral surface 30 are distributed in the circumferential direction several Ölableitrinnen 33 with helical course. In addition to the oil drainage channels 33 also form means for impact separation of oil and flow control.

According to FIG. 4 For example, the gas guide ring 3 can consist of a hollow-cylindrical element 34, for example of a woven fabric or the like, which is held in shape by means of a support body 34 '.

FIG. 5 shows a Gasleitring 3, which is designed as a self-supporting, hollow cylindrical member 35, for example of a sintered material. Here, the gas guide ring 3 is smooth on its inner circumference, that is executed without Ölableitrinnen, because the material absorbs the oil and then passes the oil in its interior down.

The FIGS. 6 and 7 show two other versions of the gas guide 3 each as a single part in longitudinal section. On the inner circumferential surface 30 are distributed here in the circumferential direction several Ölableitrinnen 33 with helical course. In addition to the oil drainage, the gutters 33 serve here as a means for impact separation of oil and for flow control. In cross section, the Ölableitrinnen 33 are L-shaped and open axially downwards.

In addition, the upper edge 31 is formed in both gas guide rings 3 as a reinforcement and also has radially inward Ölfangrinnenabschnitte 38, which are open axially downwards and extending between each two adjacent Ölableitrinnen 33 in this or one of these. In the oil-collecting gutter sections 38, if necessary, the gas-conducting ring 3 is intercepted by the gas flow during operation of the oil-mist separator on the inner circumferential surface 30 and transported up into the oil-drainage grooves 33.

According to FIG. 6 the gas guide ring 3 consists of a hollow cylindrical plastic body, which is produced in one piece with the Ölableitrinnen 33 and the Ölfangrinnenabschnitten 38 as an injection molded part.

In the example in FIG. 7 the gas guide ring 3 is formed by a non-supporting element 34, for example made of a fabric or the like, which is held in shape by means of a support body 34 '. The support body 34 'in this case comprises the Ölableitrinnen 33 and the Ölfangrinnenabschnitte 38 and is integrally manufactured as an injection molded plastic part. The element 34 made of fabric or the like can be injection-molded immediately onto the support body 34 'during an injection process or, alternatively, can be subsequently connected to the support body 34'.

Claims (21)

1. An oil mist separator (1) of a combustion engine, which is embodied as a centrifugal oil separator comprising a rotor (2), which is arranged in a housing (10) and which has the shape of a stack of plates (20), and comprising an inner circumferential surface (11) of the housing (10), which surrounds the rotor (2) radially outside and extends in axial direction of the rotor (2),
   characterised in that
   a hollow-cylindrical gas guide ring (3), which is embodied as a an individual component and which forms an impact separating surface, is inserted into the housing (10) so as to surround the rotor (2) radially outside, so as to extend in axial direction of the rotor (2) and so as not to co-rotate relative to the rotor (2).
2. The oil mist separator according to claim 1, characterised in that the gas guide ring (3) can be moved in axial direction of the rotor (2) relative to the rotor (2) and to the housing (10), wherein the cross section of a clean gas passage (32) between rotor (2) and gas guide ring (3) can be changed by means of this movement.
3. The oil mist separator according to claim 2, characterised in that the cross section of the clean gas passage (32) can be changed by means of the movement of the gas guide ring (3) in the sense that the cross section of the clean gas passage (32) is smaller in the case of a smaller clean gas volume flow and that the cross section of the clean gas passage (32) is larger in the case of a larger clean gas volume flow.
4. The oil mist separator according to claim 2 or 3, characterised in that the axial movement of the gas guide ring (3) can be produced solely by a flow of the clean gas.
5. The oil mist separator according to any one of claims 2 to 4, characterised in that an upper edge (31) of the gas guide ring (3) is embodied so as to be offset inwardly.
6. The oil mist separator according to any one of claims 2 to 5, characterised in that a prestressing force, which acts in the direction of a reduction of the cross section of the clean gas passage (32), is applied to the gas guide ring (3).
7. The oil mist separator according to claim 6, characterised in that the prestressing force, which acts on the gas guide ring (3), is generated by force of gravity or by spring force.
8. The oil mist separator according to any one of claims 1 to 7, characterised in that at least one oil drain channel (33) is embodied on the side of the inner circumference on or in the gas guide ring (3).
9. The oil mist separator according to claim 8, characterised in that the at least one oil drain channel (33) runs along at least one helical curve, which points downwards, viewed in the direction of rotation of the rotor (2).
10. The oil mist separator according to claim 8 or 9, characterised in that the at least one oil drain channel (33) is formed by means of a profile comprising an L- or U-shaped cross section, wherein an open side of the oil drain channel (33) points downwards.
11. The oil mist separator according to any one of claims 1 to 10, characterised in that the gas guide ring (3) forms a closed surface, which is free from through holes.
12. The oil mist separator according to claim 11, characterised in that the gas guide ring (3) is formed by means of a one-piece hollow cylinder made of plastic or sheet metal.
13. The oil mist separator according to any one of claims 1 to 10, characterised in that the gas guide ring (3) forms a perforated or porous surface.
14. The oil mist separator according to claim 13, characterised in that the gas guide ring (3) is formed by means of a hollow-cylindrical grate or screen or filter cloth body.
15. The oil mist separator according to any one of claims 8 to 10 and according to claim 13 or 14, characterised in that the at least one oil drain channel (33) is injection moulded to the gas guide ring (3).
16. The oil mist separator according to claim 15, characterised in that, in addition to the at least one oil drain channel (33), at least one support ring (37), preferably two support rings (37), which are axially spaced apart and which run in circumferential direction, is/are injection moulded to the gas guide ring (3).
17. The oil mist separator according to any one of claims 8 to 16, characterised in that provision is made on the gas guide ring (3), distributed across the inner circumference thereof, for a plurality of oil drain channels (33) and that an upper edge (31) of the gas guide ring (3) encompasses oil trapping channel sections (38) radially inside, which are open axially downwards and which run in each case between two adjacent oil drain channels (33) so as to fade into them or into one of them.
18. The oil mist separator according to claim 14, characterised in that the grate or screen or filter cloth body, which forms the gas guide ring (3), consists of a non-self-supporting element (34) of a woven fabric or knotted fabric or non-woven fabric or knitted fabric, preferably made of textile material, or of open-celled foam, in each case comprising an integrated support body (34') or of a self-supporting element (35) of a woven fabric or knotted fabric or non-woven fabric or knitted fabric, preferably made of metallic material or of sinter material.
19. The oil mist separator according to claim 14 or 18, characterised in that the grate or screen or filter cloth body, which forms the gas guide ring (3), has a mesh or pore size of between 10 and 300 µm.
20. The oil mist separator according to any one of claims 13 to 19, characterised in that an annular space (15) is kept free between an outer circumferential surface (30') of the gas guide ring (3) and an inner circumferential surface (11) of the housing (10) as an annular oil drain ring gap.
21. The oil mist separator according to any one of claims 1 to 20, characterised in that a deflecting ring (11'), which points into the interior of the housing (10) opposite a gas flow direction, which is present there, is attached or integrally moulded to an inner circumferential surface (11) of the housing (10) at the height of an end face of the gas guide ring (3) on the gas outlet side.

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