WO2019175079A1

WO2019175079A1 - Centrifugal separator for the separation of oil droplets from the crankcase ventilation gas of an internal combustion engine

Info

Publication number: WO2019175079A1
Application number: PCT/EP2019/055960
Authority: WO
Inventors: Eike Stitterich; Andreas Dworog; Martin Rölver; Stefan Robert
Original assignee: Hengst Se
Priority date: 2018-03-12
Filing date: 2019-03-11
Publication date: 2019-09-19
Also published as: DE102018105588A1

Abstract

The invention relates to a centrifugal separator (1) for the separation of oil droplets from the crankcase ventilation gas of an internal combustion engine, with a rotor (2) with a shaft (27) with plates (23) which are arranged above one another fixedly so as to rotate together and which form a plate stack (20), wherein adjacent plates (23) in each case delimit a flow gap (24), with a housing (3) which receives the rotor (2) with a raw gas inlet (32), a pure gas outlet (33) and an oil outlet (34), and with a rotary drive for the rotor (2). The centrifugal separator (1) according to the invention is characterized - in that the plate stack (20) is divided, as viewed in its axial direction, into two plate stack parts (21, 22) which are separated from one another in flow terms within the rotor (2) by way of a dividing element (26), - in that the raw gas inlet (32) opens into a radially inner region (21') of a first plate stack part (21), and the first plate stack part (21) can be flowed through during operation by the crankcase ventilation gas in a direction from radially on the inside to radially on the outside, - in that a second plate stack part (22) can be flowed through during operation by the crankcase ventilation gas in a direction from radially on the outside to radially on the inside, and the pure gas outlet (33) emanates from a radially inner region (22') of the second plate stack part (22), and - in that the axial spacing of mutually adjacent plates (23) is smaller in the first plate stack part (21) than in the second plate stack part (22).

Description

Description:

Centrifugal separator for separating oil droplets from the crankcase ventilation gas of an internal combustion engine

The present invention relates to a centrifugal separator for separating oil droplets from the crankcase ventilation gas of an internal combustion engine, with a rotor having a central shaft with superimposed on one another with a fixed spacing, plates forming a plate stack, adjacent plates each delimiting a flow gap, with a housing rotatably receiving the rotor housing with a raw gas inlet, a clean gas outlet and an oil outlet and with a rotary drive for the rotor.

Disc rotors of centrifugal separators for purifying crankcase ventilation gas of an internal combustion engine are preferably designed for a radial flow from inside to outside due to the requirement of low pressure in the crankcase of the internal combustion engine, taking advantage of the delivery effect of the rotor on the gas flow. This conveying effect also supports the return of the separated oil in the centrifugal separator, as seen in the gas flow direction behind the rotor, there is a higher pressure than in front of the rotor. On the other hand, it is known that in the radial direction from the outside inwardly flowed rotors with plate stack at the same boundary conditions have better oil separation, albeit the delivery effect of the rotor counteracts the flow direction, which then the use of additional conveyors, such as compressors, necessary for the gas flow.

The document DE 10 044 615 A1 discloses a bleeding device for a crankcase of an internal combustion engine with a centrifugal oil separator which has a mixture inlet for an air-oil mixture and an air outlet for clean air as well as an oil outlet for oil, known, wherein the centrifugal oil separator is formed as a plate separator. The plate separator preferably has a Housing formed stator in which a rotor is housed, which has a plurality of plates which are arranged along the rotor axis parallel to each other and coaxial with the rotor axis. In each case between two adjacent plates, a gap is formed which connects an annular space formed in the interior of the rotor with a space surrounding the rotor in the interior of the housing. Furthermore, the ventilation device may have a compressor, which is connected upstream or downstream of the plate separator, wherein the compressor is dimensioned substantially such that it at least compensates for a pressure loss that occurs during the flow through the plate separator. In a first embodiment, in the operation of the oil separator, the air stream to be depleted flows radially inwardly from the outside inwardly through the nips of the rotor, that is, against the centrifugal force generated by the rotation of the rotor, necessitating the use of the aforementioned compressor. On the one hand, the compressor serves to substantially equalize the pressure loss, which inevitably occurs during the flow through the plate separator. On the other hand, the compressor may also be dimensioned to produce a pressure rise across the separator-compressor unit. In another embodiment, the flow direction of the air stream to be de-oiled in the Teler separator is reversed, thus extending in the radial direction from the inside to the outside through the column of the rotor, in which case no separate compressor is required.

Another separator of the type mentioned is known from the document DE 10 2007 054 922 A1. This document shows a separator for separating oil mist from the crankcase ventilation gas of an internal combustion engine, in particular of a motor vehicle, with a gas cleaning space in which a rotatably mounted centrifugal rotor is arranged. The gas cleaning room has a raw gas inlet, a clean gas outlet and an oil outlet. By the raw gas inlet, the crankcase ventilation gas in a radially inner region of the centrifugal rotor can be introduced through the clean gas outlet is cleared of oil mist clean gas from the gas cleaning space and discharged through the oil outlet from the gas separated oil from the gas cleaning space. A rotary drive for the rotor is arranged in a drive chamber of the separator separate from the gas cleaning chamber and can be operated with pressurized lubricating oil of the internal combustion engine and connected to the centrifugal rotor via a shaft extending from the drive chamber into the gas cleaning chamber. The centrifugal rotor is preferably by a Tellerstapelseparator of a number of stacked, positively and / or non-positively engaged with each other and / or formed with the shaft plates. This separator is designed for a flow through the rotor in the radial direction from the inside to the outside and thus exploits the conveying effect of the rotor on the gas flow, but this does not achieve optimal oil separation from the crankcase ventilation gas.

The document DE 10 2004 057 41 1 A1 describes a disk separator which serves to remove impurities from a fluid. The disk separator comprises a rotor which rotatably supports a plurality of disks stacked axially one above the other and axially spaced from one another, and a stator which contains a dirt collecting chamber in which the rotor is arranged. In the disk separator, a fluid path is formed, which leads from an inlet into the dirt collecting chamber, from the dirt collecting chamber radially inwardly between the plates into a central outflow channel and from the outflow channel through an outlet from the separator. The dirt collecting space is divided by means of at least one throttle point axially into at least two subspaces, of which the fluid can flow out in parallel between the plates through to the outflow channel. In this case, the throttle point is formed by an annular gap, which lies in a plane perpendicular to the rotational axis extending separating plane. During operation of the plate separator, it is flowed through said fluid path by a fluid to be cleaned, at the same time the rotor is rotating. By friction and inertia effects entrained by the fluid are thereby displaced radially outward and remain so in the dirt collecting space, while the fluid can flow inwards. The field of application for such Tellerseparatoren lies in a lubricating oil circuit of an internal combustion engine, there to clean the lubricating oil from contaminants. For separation of oil droplets from the crankcase ventilation gas of an internal combustion engine, this plate separator is not designed and not suitable.

The document DE 68 928 908 T2 shows a device for liberating a liquid from a substance of higher density dispersed therein than that of the liquid. The apparatus comprises a separating centrifuge having a rotor which is rotatable about a rotation axis and forms a separation chamber, with a stack of conical separation plates arranged coaxially with the rotor in the separation chamber, and with spacing means. The spacing devices are formed and arranged between the dividing dividers so that they share several different flow paths together with the latter between each two adjacent dividing plates form, each having an inlet and a discharge area, which are at different distances from the axis of rotation of the rotor. Furthermore, the device has a device for supplying liquid to the inlet region of each flow path, and a device for removing disperse substance-removed liquid from the drainage region of each flow path. The inlet and the outlet region of each flow path lie at such radial locations that the main part of the fluid on the flow path has to cross the greater part of the radial extent of the two separation plates, between which the flow path is formed. In this case, the rotor is rotatable in a predetermined direction and in each case two successive spacer devices between two consecutive separating discs are shaped such that they each extend from the inlet to the outlet of the flow path formed between them in a direction which forms a radial component and a radial component Component in the circumferential direction of the rotor. In a preferred embodiment, the centrifuge rotor has an upper part and a lower part, which are held together axially with a locking ring. The centrifuge rotor is supported by means of a drive shaft, which is connected to the rotor lower part. The rotor parts form a separation chamber, in which two stacks of part-conical separation plates are arranged coaxially with the rotor, during operation the separation chamber rotates together with the rotor. A part-conical partition is inserted between the stacks of the separation plates. The separation plates and the partition wall are fixed radially and in their circumferential direction relative to each other. For a separation of oil droplets from the crankcase ventilation gas of an internal combustion engine, this plate separator is not designed and not suitable.

For the present invention, therefore, the object is to provide a centrifugal separator of the type mentioned, on the one hand good separation of oil droplets from the crankcase ventilation gas of an internal combustion engine and on the other hand offers a useful delivery effect for the crankcase ventilation gas, without to require an additional conveyor, such as compressors.

The object is achieved according to the invention with a centrifugal separator of the type mentioned, which is characterized

- That the stack of plates seen in its axial direction is divided into two plate stacking parts, which are fluidly separated within the rotor by a separating element, in that the crude gas inlet opens into a radially inner region of a first disk stack part and in the direction of operation of the centrifugal separator, the first disk stack part can be flowed through in a direction from radially inward to radially outward of the crankcase ventilation gas,

- That a second plate stacking part in the operation of the centrifugal separator in a direction from radially outward to radially inwardly flowed through by the crankcase ventilation gas and the clean gas outlet from a radially inner region of the second plate stacking part emanates and

- That the axial distance of adjacent plates in the first plate stacking part of the plate stack is smaller than in the second plate stacking part of the Tellersta- pels.

By the two-stage oil separation in the two sequentially flowed through by the crankcase ventilation gas plate stacking parts a particularly good separation of oil droplets from the crankcase ventilation gas is achieved what contributes especially the flowed through from the outside to the second plate stacking part. At the same time, the centrifugal separator has a conveying effect on the gas flow of the crankcase ventilation gas generated by the first stacking plate part, which can be used to avoid at least an undesired differential pressure via the centrifugal separator or even to provide a desired low pressure or negative pressure in the crankcase. In addition, the delivery effect permits active oil return through the oil outlet, preferably back into the crankcase of the associated internal combustion engine. A further advantage is that the oil droplets separated from the crankcase ventilation gas in the centrifugal separator are kept away from the clean gas outlet, which avoids the risk of entrainment of previously separated oil with the clean gas into the clean gas outlet.

The separation mechanism in centrifugal separators with a stacked rotor for separating oil droplets from the crankcase ventilation gas of an internal combustion engine is well known in itself and therefore need not be described here in detail.

Further, it is preferably provided for the centrifugal separator according to the invention that the first plate stacking part, in the radially inner region of the raw gas inlet opens, a lower plate stacking part of the. During operation of the centrifugal separator Forming plate stack and that the second plate stacking part, from the radially inner region of the clean gas outlet, forms an upper plate stacking part of the stack of plates during operation of the centrifugal separator. Since a larger proportion of the oil droplets is deposited in the first plate stack part, in this embodiment, an advantageously short path is made possible for the oil discharge from the housing of the centrifugal separator. Alternatively, the first plate stack part, in whose radially inner region the raw gas inlet opens, form an upper plate stack part of the plate stack during operation of the centrifugal separator, and the second plate stack part, from whose radially inner region the clean gas outlet originates, one lower during operation of the centrifugal separator Make plate stacking part of the plate stack. Also in this embodiment of the centrifugal separator an effective oil separation is achieved.

A further embodiment provides that the number of plates in the first telescoping stack part of the stack of plates is greater than in the second stacked stack part of the stack of trays. This ensures a uniform oil separation in the two stacked plate parts and a sufficiently large conveying effect. A favorable and thus preferred ratio of the number of plates in the first plate stacking part to the number of plates in the second plate stacking part is for example in the range of 1, 5 to 1 to 3 to 1.

It is preferably further provided that the plates each have a truncated cone-shaped contour with a radially inner, each with at least one flow passage formed flat plate member and a radially outer, non-disruptive, cone-shaped plate part. The plates thus have a simple, but effective for oil separation form and can cost-effective z. B. as injection molded parts made of plastic or as stampings made of sheet metal. In addition, here the supply and distribution of the flow of the crankcase ventilation gas to be cleaned in the first plate stacking part and the collection and discharge of the stream of purified crankcase ventilation gas in the second plate stacking part through the flow openings in the plates of the plate stack done so that the central shaft for the gas guide is not needed becomes.

In order to keep the two plate stack parts within the rotor fluidly separated from each other separating element simply this is preferably by a formed between the two plate stack parts arranged flow-through cut-off wheel.

In this case, it is further preferably provided that the separating disc forming the separating element has a shape which corresponds or approximates the shape of the plate and, like the plate, is arranged rotationally fixed on the central shaft. The separating disc can thus be manufactured simply as a variant of the plate, in a plastic divider z. B. using a replaceable injection mold insert or a sheet metal plate z. B. by omitting a punch for the central flow perforation.

Another embodiment provides that the plates each have a truncated cone-shaped contour with a radially inner, non-disruptive, flat plate part and a radially outer, non-disruptive cone-shaped plate part, that the central shaft has a hollow shaft in fluid communication with the raw gas inlet with radial, is in the flow gaps between the Tellern opening flow openings and that the separating element is formed by a arranged in the hollow central shaft lock. In this embodiment, the central shaft for the supply and distribution of the flow of the crankcase ventilation gas to be cleaned in the first plate stacking part and the collection and discharge of the flow of purified crankcase ventilation gas in the second plate stacking part is used, so here the plate with its full surface available for oil separation.

A development of the centrifugal separator envisages that all plates in the stack of plates are identical and that between each two plates in the first plate stacking part separate first, in Tellerstapelaxialrichtung lower spacers and arranged between each two plates in the second plate stacking part second, in Tellerstapelaxialrich- higher spacers are. Here, a single design of the plates is sufficient and only two different, compared to the Tellern easier, spacers are needed.

An alternative development of the centrifugal separator provides that all plates in the stack of plates are identical, that each plate in at least two different relative rotational positions with the central shaft can be brought into a rotationally fixed engagement and that each plate with two such different Ab- is executed state holders, that in dependence on a rotational position of two adjacent plates relative to each other two different axial distances of the adjacent plates in the stack of plates are adjustable. Also in this embodiment of the centrifugal separator, only a single embodiment of the plate is required, which are designed with spacers, which can be adjusted depending on angle of rotation two different plate distances.

A further alternative embodiment of the centrifugal separator provides that two different types of plates are arranged in the stack of plates and in the first plate stacking first, in Tellerstapelaxialrichtung lower spacers having plates and in the second Tellerstapelteil second, in Tellerstapelaxialrich- tion higher spacers exhibiting plates are arranged. Although two different plates are needed here, the assembly of the rotor is simplified because, when the plate is mounted on the shaft, it is not necessary to pay attention to a specific rotational position of the plate relative to one another.

Finally, it is provided for the centrifugal separator according to the invention that the housing of the centrifugal separator has a peripheral wall whose inner surface surrounds the rotor at a distance and adjoins the lower end of the oil outlet in the operation of the centrifugal separator. For discharging the separated oil precipitated on the peripheral wall, gravity is used here, which, in conjunction with the conveying effect of the rotor, ensures safe and rapid discharge and return of the oil.

In the following, embodiments of the centrifugal separator according to the invention are explained with reference to a drawing. The figures of the drawing show:

1 shows a centrifugal separator with rotor, in a schematic longitudinal section,

FIG. 2 shows a rotor of the centrifugal separator of a different design from FIG. 1, in plan view,

3 shows the rotor of Figure 2 in a longitudinal section along the section line III - III in

Figure 2, and Figure 4 shows the rotor of Figure 2 and 3 in a view obliquely from above.

In the following description of the figures, the same parts in the various drawing figures are always provided with the same reference numerals, so that not all drawings have to be explained again for each drawing figure.

FIG. 1 of the drawing shows a centrifugal separator 1 in a schematic longitudinal section. The centrifugal separator 1 has a rotor 2 and a housing 3 accommodating and surrounding the rotor 2. The rotor has a plate stack 20 made up of a plurality of plates 23 having a frusto-conical contour, which are arranged at a distance one above the other and which each have flow gaps between them Train 24. On the underside, the stack of plates 20 is bounded and held together by a stacking base 28 and on the top by a stacking attachment 28 '. By means of two bearings 29, 29 ', the rotor 2 is rotatably mounted in the housing 3 accommodating it and can be set into rotation about the axis of rotation 27' by means of a rotary drive not shown in FIG.

Here, the stack of plates 20 is composed of a first, lower plate stacking part 21 and a second, upper plate stacking part 22, each consisting of a plurality of plates 23 rotationally fixed on a central shaft 27, which is only indicated here. Between the two stacked plate parts 21, 22 a separating element 26 which separates them from one another in terms of flow is arranged, which here is designed as a separating disk adapted in its shape to the shape of the plate 23.

In the first, lower plate stacking part 21, the axial distance of the individual plates 23 from each other is smaller than the distance between the individual plates 23 in the second, upper plate stacking part 22. Furthermore, the number of plates 23 in the first, lower plate stacking part 21 is larger than the one Number of plates 23 in the upper, second plate stacking part 22.

The housing 3 has an inner space 30, in which the rotor 2 is arranged. A peripheral wall 31 of the housing 3 surrounds the rotor 2 at a radial distance. A raw gas inlet 32 is arranged centrally on the underside of the housing 3, a clean gas outlet 33 is arranged centrally on the upper side of the housing 3, and an oil outlet 34 is arranged radially on the underside of the housing 3. The central shaft 27 is here a hollow shaft in flow connection with the raw gas inlet 32 with radial flow openings opening into the flow gaps 24 between the telescopes 23. The separating element 26 can also be a blocking only the free cross section of the hollow central shaft 27 barrier.

During operation of the centrifugal separator 1, the rotor 2 is set into rapid rotation by the rotary drive (not shown here). From oil droplets to be cleaned Kurgehäuseentlüftungsgases flows, coming from the crankcase of an associated internal combustion engine, through the central Rohgaseinlass 32 and a lower part of the hollow central shaft 27 in the radially inner region 2T of the first, lower plate stacking part 21. From there flows the crankcase ventilation gas through the flow gaps 24 between the plates 23 of the first, lower telescope stacking part 21 in the radial direction outwards.

A direct axial overflow of the crankcase ventilation gas from the radially inner region 2T of the first, lower plate stacking part 21 into the radially inner region 22 'of the second, upper plate stacking part 22 is prevented by the separating element 26.

The oil droplets entrained in the gas stream first strike down on the underside of the plates 23 and are conveyed radially outwardly there by centrifugal force and finally thrown off radially outwards, after which the oil droplets 4 precipitate on the inner surface of the circumferential wall 31.

The crankcase ventilation gas exits radially outward from the flow gaps 24 between the plates 23 of the first lower plate stacking part 21, then flows radially outward of the plate stack 20 and enters the flow column 24 between the plates 23 of the second upper plate stacking part 22 on. In these flow gaps 24, the crankcase ventilation gas flows in the radial direction from outside to inside, with any remaining oil droplets still contained in the gas flow being separated and transported radially outwards by centrifugal force and then likewise being ejected onto the peripheral wall 31 of the housing 3. The cleaned crankcase ventilation gas then passes into the radially inner region 22 'of the second, upper plate stacking part 22 and from there through the upper part of the hollow central shaft 27 into the subsequent central clean gas outlet 33. The clean gas outlet 33 can, for example, be connected to an air intake tract of the associated one Internal combustion engine to be connected.

The course of the flow of the crankcase ventilation gas through the centrifugal separator 1 is illustrated in FIG. 1 by flow arrows.

The oil droplets 4 precipitated on the inner surface of the peripheral wall 31 form an oil film there, which flows downward into the oil outlet 34 under the influence of gravity and is discharged therefrom, in particular returned to the crankcase of the associated internal combustion engine. The oil outlet 34 is thus advantageously located in a region of the housing 3 through which the crankcase ventilation gas flows, which has already passed through the first, lower plate stacking part 21, but has not yet flowed through the second, upper plate stacking part 22.

Since the clean gas outlet 33 is located far away from the peripheral wall 31 of the housing 3 which collects and deposits the separated oil, there is no danger of undesired entrainment of already separated oil into the clean gas outlet 33.

FIG. 2 shows a rotor 2 of the centrifugal separator 1 in plan view. In the center of the rotor 2, a central shaft 27 is visible, on which the not visible here, by the stacking cap 28 'hidden plate of the plate stack 20 rotationally fixed, for example by means of a mutual toothing, are placed. The rotor 2 is rotatable about the axis of rotation 27 ', which corresponds to the longitudinal central axis of the shaft 27. Radially inside, a plurality of flow openings 23 'can be seen in FIG. 2, which are arranged here in the radially inner region of the stacking attachment 28' and also the plate concealed by the latter.

FIG. 3 shows the rotor 2 from FIG. 2 in a longitudinal section according to the section line III-III in FIG. 2. Central in FIG. 3 is the shaft 27, which essentially runs vertically during operation of the centrifugal separator. At the bottom of FIG. 3 is the stack subset 28, which is designed here with the shaft 27 in one piece. On the Stapelun- tersatz 28 is a first, bottom plate 23rd

The central shaft 27 here has a metallic core shown in view, for. As steel, and a surrounding jacket, in particular a molded plastic jacket, which is shown in section. The central shaft 27 is here, unlike in Figure 1, not hollow and therefore here the flow openings 23 'are provided radially inward in the plates 23 and in the stacking pedestal 28' and stacking cap 28. At the top and bottom, the central shaft 27 has in each case an unclad end region, which serves for the rotatable mounting of the rotor 2 and for the connection of its rotary drive.

Further up in FIG. 3, two further plates 23 and a separating element 26 arranged therebetween are shown. Further plates 23 provided between the lowermost plate 23 and the plate 23 arranged below the separating element 26 are not shown here for reasons of clarity, but are present in practice.

At the top in FIG. 3, the stacking attachment 28 'is shown with an uppermost plate 23 arranged directly underneath. Further, between the uppermost plate 23 and the arranged above the partition member 26 plate 23 plate 23 are not shown here for clarity, but in practice available.

All the plates 23 of the rotor 2 together form the plate stack 20. The plates 23, which are arranged below the separating element 26, form a first, lower plate stacking part 21 of the plate stack 20 and the plates 23, which are arranged above the separating element 26 , form a second, upper plate stacking part 22 of the Telelerstapels 20. The individual plates 23 and the central shaft 27 are by means of a mutual toothing in rotationally fixed engagement with each other.

A number of spacers 25. 1, 25. 2 are here formed on the underside of the plates 23, which have the form of webs extending in the radial direction of the plate 23 and spaced apart in the circumferential direction. The flow gaps 24 extend between the plates 23, which are spaced apart axially from one another by the spacers 25.1, 25.2. To produce the different disc spacings already explained with reference to FIG. 1 in the two plate stacking parts 21, 22, the spacers 25. 1 on the plates 23 in the first, lower plate stacking part 21 are designed with a smaller axial height and the spacers 25. 2 on the plates 23 executed in the second, upper plate stacking part 21 with a greater axial height compared to it.

In practice, the axial height of the flow gaps is usually only a few tenths of a millimeter and the difference of the disc spacings in the first and second disc stack parts is only a few tenths of a millimeter, so that the differences in distance are virtually invisible to the naked eye.

Instead of integrally formed spacers 25.1, 25.2, separate spacers designed as individual parts with two different axial heights between the plates 23, which are then identical to one another, can also be arranged. It is also possible that all the plates 23 in the stack of plates 20 are identical, that each plate 23 in at least two different relative rotational positions with the central shaft 27 can be brought in a rotationally fixed engagement and that each plate 23 with two such different spacers 25.1 , 25.2 is carried out that, depending on a rotational position of two adjacent plates 23 relative to each other two different axial distances of the adjacent plates 23 in the plate stack 20 are adjustable.

In each case to the right of the shaft 27, one of the flow openings 23 'is cut in the plates 23 and thus visible.

The plates 23 each have a frusto-conical contour with a radially inner, each with flow openings 23 'formed flat plate member 23.1 and a radially outer, unbroken, cone-shaped plate part 23.2.

It is also clear in FIG. 3 that the dividing element 26, which is similar in shape to the plates 23, has no flow openings and thus an immediate overflow of crankcase ventilation gas from the radially inner region 2T of the first, lower plate stacking part 21 into the radially inner region of the second , upper plate stacking part 22 is locked. This ensures that In operation, the first, lower plate stacking part 21 in the radial direction from the inside to the outside and then the second, upper plate stacking part 22 is flowed through in the radial direction from outside to inside of the crankcase ventilation gas.

Finally, FIG. 4 shows the rotor 2 from FIG. 3 in a view obliquely from above. The central shaft 27 protrudes with an uncoated end region upwards out of the remaining rotor 2 in order to arrange there, for example, a rotary bearing and / or to connect a rotary drive, not shown here.

At the bottom of FIG. 4 is the stacking pedestal 28 and at the top in FIG. 4 is the stacking attachment 28 ', which receives the stack of plates 20 between them. On the upper side, the flow openings 23 'are visible radially on the inside of the rotor 2.

Approximately halfway up the stack of plates 20 in this embodiment lies the separating element 26, which separates the first, lower plate stacking part 21 from the second, upper plate stacking part 22 within the plate stack 20 in terms of flow. The illustrated in Figure 4 left and right of the rotor 2 flow arrows is illustrated that the flow of the crankcase ventilation gas after the radially outward discharge from the first flowed through first lower plate stacking part 21 flows radially around the separator 26 around and then with a radially inward flow direction in the then flowed through the second, upper plate stacking part 22 flows.

The separation efficiency of the centrifugal separator 1 and its conveying effect on the crankcase ventilation gas and the setting of a defined pressure difference across the centrifugal separator 1 in its operation can be adjusted as needed z. B. by changing the number and / or size of the plate 23 in the plate stack 20, by changing the ratio of Telleranzahlen in the two plate stacking parts 21, 22 and / or by changing the distance of the plate 23 from each other in the plate stacking parts 21, 22 in the stack of plates 20th specifically influenced and thus adapted and optimized for the particular application of the centrifugal separator 1. LIST OF REFERENCE NUMBERS

Sign label

1 centrifugal separator

2 rotor

20 plate stacks

21 first plate stack part (bottom)

21 radially inner region of 21

22 second plate stacking part (top)

22 radially inner region of 22

23 plates

23 'flow openings in 23

23.1 radially inner plate part

23.2 radially outer plate part

24 flow gaps

25.1. 25.2 first, second spacer 26 separating element

27 central shaft

27 'rotation axis

28 stacking pedestal

28 'stacking attachment

29, 29 'camp

3 housing

30 interior

31 peripheral wall

32 raw gas inlet

33 clean gas outlet

34 oil outlet

4 oil droplets

Claims

claims:

1. Centrifugal separator (1) for separating oil droplets from the crankcase ventilation gas of an internal combustion engine, comprising a rotor (2) having a central shaft (27) with one above the other at a distance rotationally fixed, a plate stack (20) forming plates (23), wherein adjacent plates (23) each define a flow gap (24), with a rotor (2) rotatably receiving housing (3) with a Rohgas- inlet (32), a clean gas outlet (33) and an oil outlet (34) and a rotary drive for the rotor (2),

characterized ,

- That the stack of plates (20) seen in its axial direction in two plate stacking parts (21, 22) is divided, which are within the rotor (2) fluidly separated by a separating element (26),

- That the raw gas inlet (32) in a radially inner region (2T) of a first plate stacking part (21) opens and the first plate stack part (21) in the operation of the centrifugal separator (1) in a direction from radially inward to radially outwardly flowed through by the crankcase ventilation gas .

in that, during operation of the centrifugal separator (1), a second plate stack part (22) can be flowed through in a direction from radially outside to radially inward of the crankcase ventilation gas, and the clean gas outlet (33) is guided from a radially inner region (22 ') of the second plate stack part (22). 22) goes out and

- That the axial distance of adjacent plates (23) in the first plate stacking part (21) of the plate stack (20) is smaller than in the second plate stacking part (22) of the plate stack (20).

2. centrifugal separator according to claim 1, characterized in that the first plate stacking part (21), in the radially inner region (2T) of the Rohgas- inlet (32) opens, during operation of the Zentrifugalabscheiders (1) lower plate stacking part of the plate stack (20) forms and the second plate stack part (22), from the radially inner region (22 ') of the clean gas outlet (33) goes out, forms an upper plate stacking part of the plate stack (20) during operation of the centrifugal separator (1) or that the first plate stacking part (21), in des- 2, the crude gas inlet (32) opens, forms an upper plate stacking part of the plate stack (20) during operation of the centrifugal separator (1), and forms the second plate stacking part (22), from its radially inner region (22 '). ) of the clean gas outlet (33) emanating, during operation of the centrifugal separator (1) lower plate stacking part of the plate stack (20) formed.

3. Zentrifugalabscheider according to claim 1 or 2, characterized in that the number of plates (23) in the first plate stacking part (21) of the Telerslerstapels (20) is greater than in the second plate stacking part (22) of the Teler lapel stack (20 ).

4. Centrifugal separator according to one of claims 1 to 3, characterized in that the plates (23) each have a truncated cone-shaped contour with a radially inner, each with at least one Strömungsdurchbre- tion (23 ') formed flat plate member (23.1) and a radially outer, unbreakable, cone-shaped plate part (23.2) have.

5. Centrifugal separator according to one of claims 1 to 4, characterized in that the separating element (26) arranged between the two plate stacking parts (21, 22) is formed by a flow-through-free separating disk.

6. centrifugal separator according to claim 4 and 5, characterized in that the separating element (26) forming cutting disc has a shape of the plate (23) corresponding or approximate shape and as the Teller (23) rotationally fixed on the central shaft (27 ) is arranged.

7. Zentrifugalabscheider according to one of claims 1 to 3, characterized in that the plates (23) each have a truncated cone-shaped contour with a radially inner, non-disruptive flat plate member (23.1) and a radially outer, non-piercing cone-shaped plate part (23.2), that the central shaft (27) one with the raw gas inlet (32) is a fluid communicating hollow shaft having radial flow apertures opening into the flow gaps (24) between the plates (23) and the separator (26) being formed by a barrier disposed in the hollow central shaft (27) ,

8. Zentrifugalabscheider according to one of claims 1 to 7, characterized in that all the plates (23) in the stack of plates (20) are identical and that between each two plates (23) in the first plate stacking part (21) separate first, in Tellerstapelaxialrichtung lower Spacer (25.1) and between each two plates (23) in the second plate stacking part (22) separate second, in Tellerstapelaxialrichtung higher spacers (25.2) are arranged.

9. Zentrifugalabscheider according to one of claims 1 to 7, characterized in that all the plates (23) in the stack of plates (20) are identical, that each plate (23) in at least two different relative rotational positions with the central shaft (27) in is rotationally engageable engagement and that each plate (23) with two such different spacers (25.1, 25.2) is executed, that in dependence on a rotational position of two adjacent plates (23) relative to each other two different axial distances of the adjacent plates (23) in the stack of plates (20) are adjustable.

10. Zentrifugalabscheider according to one of claims 1 to 7, characterized in that in the stack of plates (20) two different types of plates (23) are arranged and that in the first plate stacking part (21) first, in Tellerstapelaxialrichtung lower spacers (25.1 ) are arranged plates (23) and in the second plate stacking part (22) second, in Tellerstapelaxialrichtung höhe- spacers (25.2) having plates (23) are arranged.

1 1. Centrifugal separator according to one of claims 1 to 10, characterized in that the housing (3) of the centrifugal separator (1) has a circumferential wall (31) whose inner surface surrounds the rotor (2) at a distance and that the oil outlet (34) adjoins the lower end of the inner surface of the peripheral wall (31) during operation of the centrifugal separator (1).