DE202007003292U1 - Oil separator with at least one cyclone - Google Patents

Abstract

oil separator (1) with at least one cyclone (4) for separating oil mist from the crankcase ventilation gas of an internal combustion engine, in particular of a motor vehicle, wherein the oil separator (1) one connectable to the crankcase of the internal combustion engine Gas inlet (3), one with an air intake tract of the internal combustion engine connectable, designed as a dip tube (6) gas outlet (7) a downstream clean gas area (9) and at the lower end of Cyclones (4) connectable to an oil sump of the internal combustion engine oil outlet (12) with a downstream oil collection area (11), between the clean gas area (9) and the oil collecting area (11) a flow connection (10), characterized in that in the oil outlet (12) at the lower end of the cyclone (4) a a gas barrier by axial flow reversal of the gas flow in the cyclone (4) causing, for sedimenting oil permeable constriction (14) of the cross section with a above the constriction (14) arranged stepped Paragraph (13).

Description

The The invention relates to an oil separator with at least a cyclone for separating oil mist from the crankcase ventilation gas an internal combustion engine, in particular a motor vehicle, wherein the oil separator one with the crankcase of the Internal combustion engine connectable gas inlet, one with an air intake tract the internal combustion engine connectable, designed as a dip tube Gas outlet with a downstream clean gas area and at the bottom of the cyclone one with an oil sump of the internal combustion engine connectable oil outlet with a downstream oil collection area wherein between the clean gas area and the oil collection area there is a flow connection.

Further The invention relates to an oil separator with several Cyclones for separating oil mist from the crankcase ventilation gas an internal combustion engine, in particular a motor vehicle, wherein the oil separator per cyclone one with the crankcase the internal combustion engine connectable gas inlet, one with an air intake tract connectable to the internal combustion engine, each formed as a dip tube Gas outlet with a downstream clean gas area and at the bottom End of each cyclone one each with an oil sump of the internal combustion engine connectable oil outlet with a downstream, for each Having multiple or all cyclones common oil collection area.

It is known, cyclones as oil separators in the crankcase ventilation system to use in internal combustion engines. Depending on the application, for. B. Otto engine or diesel engine or type of ventilation system in the crankcase, meet the cyclones depending from their interpretation the requirements, the oil content to reduce in blow-by gas. Stricter exhaust and environmental regulations always require new innovations from the automotive industry. With the goal of further reducing fuel consumption and emissions not only the combustion process itself, but also optimized also different engine components continuously improved. These include u. a. complex oil separator systems for the separation of the oil-gas mixture in the blow-by gas, the one enable a significant reduction in emissions.

While of the combustion process in internal combustion engines small amounts of the fuel-air mixture and the forming combustion exhaust gases past the piston rings and tear the finest oil droplets of the resulting piston and cylinders with oil. That so called blow-by gas is through the finest oil droplets, but also by fuel residues, water and soot particles contaminated. For environmental reasons, blow-by gas and entrained components are not released into the environment but the blow-by gas must, if possible oil-free, be returned to the combustion. It is therefore necessary the blow-by gas as completely as possible from the to clean with entrained oil.

Out EP 1 095 209 B1 an oil separator is known in which the dip tube bil det a portion of a lid of the cyclone. From the top of the lid, so from the clean gas area, leads a Ölableitkanal as a flow connection separately from the dip tube down to the oil outlet or oil sump. This flow connection serves to dissipate any oil that may have entered the clean gas area from there before it enters the intake tract of the internal combustion engine and leads to disturbances or damage there. Appropriately, the lower end of the Ölableitkanals is executed with a siphon or check valve to safely exclude an undesirable gas flow against the Ölfließrichtung. A disadvantage of this oil separator is the high cost of integrating the Ölableitkanals and the siphon or check valve in the separator during its production, which leads to increased production costs.

This space is optimally utilized and high separation efficiency in the crankcase ventilation of internal combustion engines can be achieved, it is from the EP 1 080 298 B1 known, instead of a cyclone several smaller parallel cyclones, a so-called multi-cyclone use. The oil flows of the individual cyclones of such a multi-cyclone usually open into a common oil-collecting region, which in turn can be connected or connected to the oil sump of the associated internal combustion engine. The cyclones of the separator are thus in communication with each other via the oil collection area. With cyclones that are not optimally flown or with cyclones that are not exactly the same in multicyclones, there is an uneven flow or volume flow distribution through the cyclones. This leads to so-called cross flows from single cyclone to single cyclone through their oil outlets and thus to uneven and not optimally formed gas flow vortex. This leads to incomplete separation in cyclones. These separation efficiency losses in multicyclones by cross flows through the oil outlets have long been known and it has already been pointed out that the advantage of multicyclones over individual cyclones is usually eliminated by the problems mentioned. This problem becomes progressively stronger as the size of the cyclones decreases, because deviations of the parts of the cyclones swept by the gas flow from the ideal shape have a particularly disturbing effect on small cyclones. Sources of interference k nen z. B. already be small demolding burrs that arise in a production of the separator as a spray or diecasting. In order to avoid such burrs, it is often necessary to rework the surfaces of the separator which are contacted by the gas flow, which represents a considerable additional manufacturing outlay, which increases the production costs.

For oil separators with a cyclone can disturbing flow errors occur when a flow connection between the clean gas area and the oil collection area is present, which for an oil removal from the clean gas area itself is desired. Even with individual cyclones, in which z. B. due to the manufacturing process, no ideal target cyclone geometry can be implemented, problems occur. It does not form optimal vortex flow for the deposition in the Cyclone and it will not reach the desired separation efficiency.

For oil separators with multiple cyclones, false flows can even occur in two ways, namely as a cross-flow from cyclone to cyclone through their oil outlets and / or as a false flow through the oil outlet of one or several cyclones and possibly also provided here flow connection between the clean gas area and the oil collecting area to Clean side. Both disturbances can overlap, which further worsens the separation efficiency, or even practical collapses.

It is therefore an object of the invention, cyclone oil separator to create the aforementioned type in which disturbing Transverse and / or false flows and thus separation efficiency losses be avoided with the simplest possible means and at a safe oil drain and a cost effective Production can be achieved.

According to the invention the task with oil separators of the type mentioned having solved the features of claim 1 or claim 2 have.

By The constriction will be the free cross section on the respective one Position on the component axis of the cyclone reduced. The cyclone vortex becomes stabilized by the stepped heel and it will a defined and complete flow reversal the cyclone vortex causes by means of the paragraph. It comes independently from the flow or despite faulty cyclone geometry, z. B. by burrs or bumps on the inner cyclone walls, to no blowing off via the oil outlet or to none Cross flows in the oil separator. The gas flows completely over the dip tube or the dip tubes with several cyclones in the oil separator to the clean side. Just The oil separated in the cyclone flows under gravity down through the inner surface of the cyclone remove the oil outlet into the oil collection area. There no Gas flowing through the oil outlet can be a very simply designed flow connection, in particular without siphon or check valve, between the clean gas area and the oil collection area, in the simplest Case an opening, z. B. a hole in a clean gas area from the oil collection area separating wall of Ölabschei ders. An extensive oil mist separation with high efficiency is thus guaranteed.

The inventive solution is for all common cyclone versions suitable, in particular for cyclones with cone angle and with tangential or axial Gas inlet. Under the cyclone is a device to understand in which a circular cavity is present, which is nearby his base, d. H. usually in the upper range, one or more Gas supply lines, z. B. Tangentialzuleitungen, as well as a central and axially arranged immersion tube, while in the Base opposite end, d. H. the pointed end or cone in the generally lower range, a derivative, for example, over an oil drain pipe or an oil drain hole, is available.

By the cyclone oil separator according to the invention There are some advantages. In particular, a results for a favorable vortex flow effective geometry at the oil outlet at the bottom of the cyclone through the constriction of the cross section and the stepped shoulder, resulting in Improvement of the separation function of the cyclone or multicyclone, especially under production conditions in mass production, contributes. In addition, this solution during the production of the oil separator in mass production technically simple and inexpensive to implement.

Further Measures and advantages emerge from the subclaims.

A First embodiment suggests that the oil outlet with constriction and step-shaped heel in one essentially hollow cylindrical, a lower end portion of the Cyclone forming, tubular Zyklonendab section lies.

Farther can the stepped heel of the oil outlet right-angled, d. H. transverse, aligned with its inner surface be.

According to an alternative embodiment of the oil separator according to the invention, the stepped shoulder of the oil outlet is oriented obliquely to its inner surface, wherein the slope is formed so that a gradient results from radially outside to radially inside or vice versa. In a gradient radially inward, the oil on the Slanted directed in the narrowed diameter portion of the stepped shoulder of the oil outlet. In reverse slope, a certain dirt collecting area is formed on the top of the heel, which prevents obstruction of the constriction of the oil outlet.

Preferably forms the slope of the step-shaped heel the oil outlet to the radial plane an angle between 15 and 45 °, preferably about 30 °.

Advantageous reduces the narrowing in the oil outlet of its original one Diameter at least 30%, preferably at least 50%. To Above, the degree of narrowing is limited by the fact that a sufficient oil discharge through the oil outlet must be ensured to a backwater of oil in the cyclone and / or clogging of the oil outlet to avoid. There is a clogging of the reduced oil outlet but hardly to be expected, because just nearby narrowing of cross-section of an oil outlet that the cyclone gas flowing through a high flow velocity, especially near the inner surface of the cyclone, thereby avoiding permanent deposits.

To a further embodiment of the oil separator is the Constriction in the oil outlet in one piece with a / lower Zyklonendabschnitt formed, which is a particularly simple Production, z. B. in plastic injection, allowed.

alternative this can be the constriction in the oil outlet through a in the oil outlet used aperture can be formed. This offers the possibility to equip a standard cyclone with different constrictions to optimize its function depending on the conditions of use. alternative The aperture can also be placed on the lower end of the oil outlet be.

Prefers is the aperture in the form of a hollow cylindrical body or a snap ring formed, making the aperture cost-effective power.

After all is inventively still provided that the Aperture in different axial positions in the oil outlet is determinable. The one chosen for the respective application axial position can be optimized by experiments.

It It should be noted that the measures according to the invention both in an oil separator with a single cyclone as also applicable to an oil separator with several cyclones are.

embodiments The invention will be described in the following description with reference to Embodiments shown in the drawings are explained in more detail. Show it:

1 a cyclone oil separator with a cyclone, in longitudinal section,

2 to 8th various embodiments in an enlarged sectional view according to the designated "X" section of the cyclone oil separator after 1 , and

9 a cyclone oil separator with several cyclones in longitudinal section.

The oil separator 1 according to 1 is for separating oil mist from the crankcase ventilation gas of an internal combustion engine, in particular a motor vehicle, is provided. The oil separator 1 has a housing 2 that has an open top 2 ' Has; here can z. B. an unillustrated lid are attached, which forms the beginning of a leading to the intake of the associated internal combustion engine clean gas line.

In the case 2 is a single cyclone 4 with a tangential gas inlet 3 accommodated. The cyclone 4 has, as usual and known, a cylindrical upper part and a lower part, which is funnel-shaped narrower down. At the top is the cyclone 4 through a lid 5 completed, in which a dip tube 6 as a gas outlet 7 is formed.

During operation of the oil separator 1 passes through the gas inlet 3 Crankcase ventilation gas of an internal combustion engine in a tangential direction in the interior 8th of the cyclone 4 and is placed in this in a helical rotary flow, in which the entrained oil droplets are carried by centrifugal forces to the outside, on the inner wall of the cyclone 4 never knock down and flow down. The most of the oil components freed gas stream is at the bottom of the interior 8th of the cyclone 4 deflected inwards and upwards and flows through the gas outlet 7 forming dip tube 6 upwards. The dip tube 6 ends just above the top of the lid 5 where there is a clean gas area 9 followed by a sudden increase in cross-section.

Furthermore, the housing comprises 2 in its lower part an oil collecting area 11 into the lower end of the cyclone 4 protrudes, which is the oil outlet 12 forms.

The housing 2 of the oil separator 1 further has a clean oil drain hole 10 on. The oil drain hole 10 connects the clean gas area 9 with the oil collection area 11 , The oil collection area 11 has an oil drain hole 15 in his bottom, with a leaf valve 15 ' is equipped, which automatically opens at suitable for an oil drain pressure conditions and is otherwise closed.

In the in 1 right upper part of the housing 2 is further a spring-loaded pressure relief valve 17 arranged, which opens upon the occurrence of a harmful overpressure in the crankcase and a discharge of crankcase ventilation gas from the crankcase in the intake tract of the internal combustion engine, bypassing the cyclone 4 allowed. A limited oil separation is also carried out by sharp flow deflection and impact separation on the pressure relief valve 17 ,

In the oil outlet 12 at the bottom of the cyclone 4 is one-storey with this a stepped heel 13 with a narrowing 14 the cross section of the oil outlet 12 intended. This paragraph 13 with the constriction 14 influences the rotating flow in the cyclone 4 positively and thus improves the separation efficiency of the cyclone 4 ,

The embodiments according to the 2 to 8th show only the area marked "X" of the cyclone 4 according to 1 and are shown enlarged.

Like from the 2 to 8th is apparent, here is the step-shaped paragraph 13 of the oil outlet 12 each aligned at right angles to the inner surface. This narrows the narrowing 14 in the oil outlet 12 its original diameter by at least 30%.

According to the embodiments of the 2 to 4 become the constriction 14 and the step-shaped heel 13 each through a panel 16 formed as a built-in part in the oil outlet 12 is introduced.

In the embodiments according to the 2 to 4 is the aperture 16 designed as a hollow cylindrical insert part, which is used to form the step-shaped shoulder 13 in the oil outlet 12 of the cyclone 4 is used, for. B. pressed or glued or welded. In 2 is the aperture 16 at the bottom, in 3 approximately in the middle and in 4 at the upper end of the here tubular Ölauslasses 12 arranged, thereby varying degrees on the gas flow in the cyclone 4 Influence can be taken.

The 5 shows an embodiment in which the constriction 14 and the step-shaped heel 13 integral with the rest of the cyclone 4 here with its lower, tubular Zyklonendabschnitt with the oil outlet 12 , is trained. Also in this design, the narrowing can 14 with the paragraph 13 in different axial positions of the oil outlet 12 be arranged by a mold for injection molding of the cyclone 4 is changed accordingly. This version of the cyclone 4 does not require any assembly work to attach the constriction 14 and the paragraph 13 , which makes the production, preferably in plastic injection molding, particularly simple and economical.

According to the in 6 the embodiment shown is the aperture 16 with the constriction 14 as an insert in the manner of a snap ring in the oil outlet 12 of the cyclone 4 used, preferably pressed from below, so that the aperture 16 safely in the oil outlet without further action 12 holds.

In 7 an example is shown in which the aperture 16 with the constriction 14 and the paragraph 13 is designed as Aufsetzkappe, which on the lower end of the Ölauslasses 12 z. B. screwed or glued or welded and this surrounds and attached to an outer radial collar 18 of the oil outlet 12 supported. Here can be advantageous without form changes to the rest of the cyclone different apertures, also easily replaceable, are attached.

In the embodiment according to 8th is the step-shaped heel 13 immediately at the bottom of the conical section of the cyclone 4 formed integrally with this. In the paragraph 13 is centrally and radially inwardly spaced from the lower end of the conical cyclone wall region, the constriction 14 of the oil drain 12 Here is the constriction 14 the entire oil outlet 12 that also forms here in the oil-collecting area 11 empties.

Finally shows 9 an example of an oil separator 1 , the several, here three cyclones 4 includes. Every cyclone 4 has a tubular oil outlet at the lower end 12 , which in each case at its lower end in one piece the stepped shoulder 13 with the constriction 14 of the oil drain 12 to the oil collection area 11 having. Even with the multiple cyclone, the previously described different embodiments of the constriction 14 in the oil outlet 12 be used.

As with the example 1 also has the oil collection area 11 in 9 an oil drain opening 15 in his bottom, with a leaf valve 15 ' equipped, which automatically opens at suitable for an oil drain in the oil sump pressure conditions and is otherwise closed.

Again, in the in 9 right upper part of the housing 2 a spring-loaded pressure relief valve 17 arranged, which opens at the occurrence of harmful overpressure in the crankcase and a discharge of Kurbelgehäuseentlüf tion gas from the crankcase into the intake tract of the internal combustion engine, bypassing the cyclones 4 allowed. A limited oil separation takes place here by sharp flow deflection and impact separation on the pressure relief valve 17 ,

1

oil separator

2

casing

2 '

open top of 2

3

gas inlet

4

cyclone

5

cover

6

dip tube

7

gas outlet

8th

inner space

9

Clean gas area

10

clean oil drain hole

11

Oil collection area

12

oil outlet

13

stepped paragraph

14

narrowing

15

Oil drain opening

15 '

reed valve

16

cover

17

Pressure relief valve

18

collar

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1095209 B1 [0005]
• - EP 1080298 B1 [0006]

Claims (11)

Oil separator ( 1 ) with at least one cyclone ( 4 ) for separating oil mist from the crankcase ventilation gas of an internal combustion engine, in particular of a motor vehicle, wherein the oil separator ( 1 ) a connectable to the crankcase of the internal combustion engine gas inlet ( 3 ), connectable with an air intake tract of the internal combustion engine, as a dip tube ( 6 ) formed gas outlet ( 7 ) with a downstream clean gas area ( 9 ) and at the lower end of the cyclone ( 4 ) an oil outlet connectable to an oil sump of the internal combustion engine ( 12 ) with a downstream oil collection area ( 11 ), wherein between the clean gas area ( 9 ) and the oil collection area ( 11 ) a flow connection ( 10 ), characterized in that in the oil outlet ( 12 ) at the lower end of the cyclone ( 4 ) a gas barrier by axial flow reversal of the gas flow in the cyclone ( 4 ) causing, for sedimenting oil permeable constriction ( 14 ) of the cross section with one above the constriction ( 14 ) stepped step ( 13 ) is provided. Oil separator ( 1 ) with several cyclones ( 4 ) for separating oil mist from the crankcase ventilation gas of an internal combustion engine, in particular egg nes motor vehicle, wherein the oil separator ( 1 ) per cyclone ( 4 ) a connectable to the crankcase of the internal combustion engine gas inlet ( 3 ), one connectable with an air intake tract of the internal combustion engine, each as a dip tube ( 6 ) formed gas outlet ( 7 ) with a downstream clean gas area ( 9 ) and at the lower end of each cyclone ( 4 ) each connectable to an oil sump of the internal combustion engine oil outlet ( 12 ) with a downstream, for all cyclones ( 4 ) common oil collection area ( 11 ), characterized in that in the oil outlet ( 12 ) at the lower end of each cyclone ( 4 ) a gas barrier by axial flow reversal of the gas flow in the cyclone ( 4 ) causing, for sedimenting oil permeable constriction ( 14 ) of the cross section with one above the constriction ( 14 ) stepped step ( 13 ) is provided. Oil separator according to claim 1 or 2, characterized in that the oil outlet ( 12 ) with the narrowing ( 14 ) and the stepped shoulder ( 13 ) in a substantially hollow cylindrical, a lower end portion of the cyclone ( 4 ) forming, tubular Zyklonendabschnitt lies. Oil separator according to one of claims 1 to 3, characterized in that the stepped shoulder ( 13 ) of the oil outlet ( 12 ) is aligned at right angles to its inner surface in a radial plane. Oil separator according to one of claims 1 to 3, characterized in that the stepped shoulder ( 13 ) of the oil outlet ( 12 ) is oriented obliquely to the inner surface, wherein the slope is formed relative to a radial plane so that a gradient from radially outside to radially inside or vice versa results. Oil separator according to claim 5, characterized in that the slope of the stepped shoulder ( 13 ) of the oil outlet ( 12 ) to the radial plane forms an angle between 15 and 45 °, preferably of about 30 °. Oil separator according to one of claims 1 to 6, characterized in that the constriction ( 14 ) in the oil outlet ( 12 ) whose original diameter is reduced by at least 30%, preferably by at least 50%. Oil separator according to one of claims 1 to 7, characterized in that the constriction ( 14 ) in the oil outlet ( 12 ) is integrally formed with a / the lower Zyklonendabschnitt. Oil separator according to one of claims 1 to 7, characterized in that the constriction ( 14 ) in the oil outlet ( 12 ) through one in the oil outlet ( 12 ) or on the oil outlet ( 12 ) patch ( 16 ) is formed. Oil separator according to claim 9, characterized in that the diaphragm ( 16 ) is formed in the form of a hollow cylindrical body or a snap ring. Oil separator according to claim 9 or 10, characterized in that the diaphragm ( 16 ) in different axial positions in the oil outlet ( 12 ) is determinable.