Patent Application
20160138446
The present invention relates to an oil separator, particularly for crankcase ventilation of an internal combustion engine, having a hollow member which extends axially in a longitudinal axis and through which a gas flow which is charged with oil can flow, wherein an oil separation member which is provided with an axial passage and which can be flowed against by the gas flow is formed in the hollow member.
In internal combustion engines and piston compressors, there are in practice observed leakage losses which may be attributed to an incomplete sealing, for example, of the piston/cylinder path or the valve guides in the cylinder head. The leakage losses are referred to as blowby gas and contain a substantial proportion of oil. With respect to internal combustion engines, it is therefore conventional to direct the blowby gas which occurs during operation of the internal combustion engine back into the intake tract of the internal combustion engine. In order, on the one hand, to minimize the oil loss as a result of the blowby gas and, on the other hand, to ensure optimum combustion and minimal environmental damage, it is known to supply the blowby gas to an oil separator and to direct the separated oil back into the oil circuit. In this instance, it is sought to configure corresponding oil separation systems to be as simple as possible but nevertheless to be reliable and efficient. Another aspect for improving oil separators relates to a minimal flow resistance to which the gas flow is subjected when the oil separator is flowed through. However, a high separation capacity is necessary in order to minimize the output of residual oil in the charge air tract, in particular in order to prevent air mass measuring members and turbochargers from becoming fouled by oil.
DE 10 2009 012 400 A1 sets out an oil separator which is suitable for crankcase ventilation of an internal combustion engine. The oil separator has as the housing a hollow member which can be formed, for example, by a portion of a camshaft or the hollow member is constructed to be tubular and is integrated in a cylinder head cover of an internal combustion engine. A torsion generator is arranged in the hollow member and the hollow member has an end-side supply opening for introducing the gas flow and a discharge opening for discharging the gas flow. The gas flow introduced into the hollow member may also guide oil in the form of oil mist or spray droplets which are intended to be removed from the gas flow by the oil separator. To this end, the hollow space further has a discharge opening which is for discharging separated oil and which is constructed separately from the discharge of the gas flow which has been purged of oil.
The oil separator set out uses a torsion effect which can be used in a particularly advantageous manner when the oil separator is formed in a rotating camshaft which forms the hollow member of the oil separator. To this end, there is provided in the hollow member a torsion generator which has a plurality of helical flow channels and through which a torsion is introduced into the gas flow which is charged with oil. As a result of the associated change in the flow direction of the gas flow, oil droplets which are also carried in the gas flow are separated on the inner wall of the hollow member and, as a result of the throughflow of the hollow member in the longitudinal direction, the oil droplets reach the outer region of the oil separation ring, by which the gas flow is separated in the central region of the hollow member from the oil flow in the wall region of the hollow member. Finally, after the oil separation ring has been arranged, the oil can be separated by the discharge opening for the oil from the discharge opening of the cleaned gas flow which is subsequently supplied to the discharge tract of the internal combustion engine or, for example, a piston compressor. In order to form the oil separation ring, it is set out that it can be constructed from a porous plastics material or a sintered material, wherein plastics or metal braided material can also be advantageously used. Such braided materials form a large number of hollow spaces and labyrinth-like formations, whereby the separation of the oil from the gas flow is further promoted. As a result of the torsion, the oil droplets are conveyed radially outward in relation to the longitudinal axis of the hollow member and the gas flow is guided through the central passage in the oil separation ring.
As a result of the rotational movement which is introduced into the gas flow by the torsion generator, there is produced during flow through the oil separator a substantial flow resistance in the gas flow, by which the separation power is again reduced by lower flow rates through the oil separator.
An object of the invention is to develop an oil separator, in particular for the crankcase ventilation of an internal combustion engine, which allows a high separation power of oil from a gas flow and which is particularly developed in that a flow resistance of the gas flow which is as small as possible is produced as a result of the hollow member.
This object is achieved on the basis of an oil separator in accordance with the preamble of claim 1 in conjunction with the characterizing features. Advantageous developments of the invention are set out in the dependent claims.
The invention includes the technical teaching that, in the region of the passage of the oil separation member, there is formed in the hollow member a redirection member which can be flowed against with the gas flow by the gas flow substantially from the direction of the longitudinal axis and by which the gas flow can be redirected radially outward against the inner side of the oil separation member.
The invention is based on the notion of directing the gas flow which is charged with oil at the inner side against the oil separator which is formed, for example, to be tubular or sleeve-like. The oil from the gas flow can be separated from the gas flow with the oil separator and the gas flow can in a state purged of oil flow through the oil separator through the, for example, central axial passage, wherein the separated oil can be discharged between the outer side of the oil separation member and the inner wall of the tubular member. Consequently, the oil separation member forms, in the continuing path of the gas flow, a barrier between the separated oil and the gas flow, wherein the oil can be discharged from the hollow member after passing through the oil separation member and can be supplied to the oil circuit of the internal combustion engine again. The cleaned gas flow can be directed out of the hollow member and supplied to the charge air tract of the internal combustion engine.
The oil separation member can extend in a substantially rotationally symmetrical manner about the longitudinal axis of the hollow member and the oil separation member may be formed in the hollow member in such a manner that substantially the entire gas flow passes through the passage in the oil separation member. The redirection member can advantageously be formed centrally in the passage of the oil separation member and it can also extend in a rotationally symmetrical manner about the longitudinal axis. In this instance, it is particularly advantageous for the redirection member to be located in the rear third of the oil separation member when viewed in the downstream direction, that is to say, located in the direction of flow, whereby the gas flow is redirected in such a manner that it is directed substantially over the entire length of the oil separation member against the inner side thereof. In this instance, the redirection member can comprise an outer diameter which is determined so that the purged gas flow can flow between the inner diameter of the oil separation member and the outer diameter of the redirection member with low pressure loss. The indication of the arrangement or orientation formed in a downstream direction reproduces in accordance with the present invention only a directional indication which describes a direction which is orientated in or with a possible gas flow direction.
In a particularly advantageous manner, the redirection member and in particular the oil separation member may be constructed in a rotationally symmetrical manner, wherein the redirection member may have a flow tip which is located in the longitudinal axis and which has a redirection contour which increases downstream, preferably in a hyperbola-like manner. As a result of the hyperbola-like redirection contour, there is produced a rotational member which forms a peripheral flow channel so that the redirection of the flow is carried out comparatively slowly in order to prevent the oil which is carried in the gas flow from already becoming separated on the surface of the redirection member. The redirection of the gas flow by the redirection member against the inner side of the oil separation member is carried out in such a manner that the gas flow acts on the inner side of the oil separation member substantially vertically in order to achieve a particular impactor effect. As a result of the impactor effect, there is brought about a powerful subsequent redirection of the gas flow which the mass-charged droplets of oil cannot follow, and are taken up by the oil separation member. The oil in the gas flow may be present in the form of oil mist or oil droplets which can travel through the oil separation member in order to finally guide it further at the outer side of the oil separation member between the oil separation member and the inner side of the hollow member downstream in a state separated from the purged gas flow.
It is particularly advantageous for the oil separation member to be formed in an elongate manner in the direction of the longitudinal axis and in particular in a funnel-like manner, wherein the funnel-like shape is orientated so as to be open counter to the flow direction of the gas flow. It is thereby brought about that the gas flow does not have to be redirected by the redirection member, for example, by 90°, as would be necessary in order to allow the gas flow to strike substantially perpendicularly the inner side of a hollow-cylindrical member. As a result of the funnel-like shape, it is instead possible for the redirection of the gas flow to have to be produced, for example, substantially only through from 45° to 60°, in order already to strike substantially perpendicularly the inner side of the funnel-like oil separation member and in order to obtain a corresponding impactor effect.
For structural reasons, it is further advantageous for the redirection member to be received in the region of the passage of the oil separation member in a retaining manner by a retention member, wherein radial gaps through which the gas flow can flow for the redirection thereof can be formed in the retention member. The radial gaps may already be separated from each other by fan-like plates which already bring about, in addition to the redirection member, upstream of the redirection member a redirection of the gas flow in the direction toward the inner side of the oil separation member. The redirection of the gas flow is carried out in principle so as to apply a radial flow component which is superimposed on the axial flow component of the gas flow in the direction of the longitudinal axis of the hollow member. The retention member thereby forms a type of basket which comprises openings in order to form the radial gaps, and the basket-like retention member opens in the redirection member, wherein the redirection member and the retention member may be constructed so as to be integral, for example, from a plastics component.
In a further advantageous manner, there may be provision for there to be arranged, upstream of the passage of the oil separation member, an inlet funnel, by which the gas flow can be accelerated into the passage of the oil separation member. As a result of the arrangement of the inlet funnel, it is particularly possible for the gas flow charged with oil not to already strike the oil separation member at the end side. As a result of the inlet funnel, the gas flow is pre-accelerated in order to already have a higher speed before redirection by the redirection member and by the radial gaps in the retention member. Subsequently, the gas flow can be further accelerated because another flow constriction is produced by the radial gaps against the inner side of the oil separation member.
In order to advantageously influence the behavior of the gas flow after passing through the oil separation member, there may be formed in the hollow member downstream of the oil separation member an opening funnel which forms a diffuser. The opening funnel is open in the downstream direction, that is to say, the opening funnel has a greater inner diameter with increasing distance from the oil separation member, and can increase up to the inner diameter of the hollow member. The arrangement of the diffuser downstream of the oil separation member may result in a further decrease of the pressure loss of the gas flow in the opening funnel, whereby the flow resistance of the gas flow is further reduced when the flow passes through the oil separator. The inlet funnel for accelerating the gas flow may merge into the retention member with the radial gaps, for example, in an integral manner, wherein at the side of the oil separation member the opening funnel can abut it. In this instance, the smallest diameter of the opening funnel may substantially correspond to the smallest diameter of the funnel-like oil separation member. The inlet funnel can project into the funnel-like oil separation member at least in the transition to the retention member, wherein the redirection member can be arranged in the region and in particular shortly before the region of the smallest cross-section of flow which is formed by the transition of the oil separation member to the opening funnel.
The oil separation member may be formed at least partially from a nonwoven material. Other materials for forming the oil separation member may be porous plastics materials or sintered materials, wherein braided materials comprising plastics material or metal can advantageously be used. In particular, the oil separation member may be formed from a material which is not contaminated by the introduction of oil and other particulates, in particular impurities, and the oil can pass through the material of the oil separation member in order, for example, to leave the oil separation member again at the side remote from flow.
According to another advantageous aspect of the present invention, the oil separation member and in particular the nonwoven material may have a gas-permeability which is determined in such a manner that the gas flow flows partially through the oil separation member. In particular when the gas flow which is guided by the oil separator becomes more powerful, both an impactor effect and a filter effect can be achieved by the oil separation member if at least a portion of the gas flow passes through the oil separation member. Consequently, a first portion can be redirected at the inner side of the oil separation member using an impactor effect in order finally to leave the oil separation member through the passage thereof. Another portion of the gas flow can pass through the material of the oil separation member and be further conveyed with the separated oil at the outer side of the opening funnel, in particular in the radial gap between the opening funnel and the inner side of the hollow member. The radial gap which is formed between the outer side of the opening funnel and the inner side of the hollow member allows guiding of the gas flow so that the oil is separated from the gas flow by the increased wall contact in order also to obtain a cleaning effect. In particular after the gas has passed through the oil separation member, the oil is in droplet form and can travel along the outer side of the opening funnel or along the inner side of the hollow member in order finally to be supplied to a separation opening.
In a particularly advantageous manner, the hollow member can be formed by at least one portion of a camshaft of an internal combustion engine or the hollow member is constructed to be an integral component of a cylinder head cover of an internal combustion engine. Particularly when the hollow member forms a portion of a camshaft, it rotates during operation of the internal combustion engine so that the redirection of the gas flow radially outward is supported by the rotation of the hollow member. The redirection member, the retention member, the inlet funnel and the opening funnel and in particular the oil separation member can also rotate with the hollow member so that a torsion which supports outward displacement of the oil is formed in the gas flow. Consequently, by the oil separation member being subjected to flow, the oil is guided in an increased manner against the inner side of the oil separation member so that the redirection of the gas flow by the redirection member with the rotation of the hollow member allows an increasing effect for separating the oil at the oil separation member.
As a result of the embodiment of the oil separator according to the invention, a very small pressure loss of the gas flow during flow through the oil separator is achieved. In particular, very narrow cross-sections of flow are prevented, as used in nozzle openings for flowing against an oil separator. The cross-sections of flow for the gas flow to flow through are simply reduced slightly and, as a result of the flow contour of the redirection member in the manner of a half rotational hyperboloid, there is produced a gentle redirection of the gas flow against the inner side of the funnel-like oil separation member without significant pressure losses thereby being produced.
According to another embodiment, a disc-like oil separation ring may be located upstream of the elongate oil separation member, wherein, according to still another embodiment, a flow guiding member having a flow contour which increases downstream can be located upstream of the disc-like oil separation ring. It is thereby possible for the oil separator to have two oil separation members which comprise, for example, a nonwoven material, and which can be flowed through one after the other in the flow path of the gas flow. The oil separation ring can be acted on with a weak gas flow, for example, only at the surface, as can the downstream main oil separation member, so that the gas flow does not completely flow through the nonwoven material. The gas flow passes the oil separation ring through a center opening. If the gas flow is more powerful, it can flow through the oil separation ring. The oil can be separated from the gas flow in both variants so that the oil runs off in droplet form at the inner side on the hollow member.
According to another variant, the redirection member does not have to be constructed in a rotationally symmetrical manner and it may also be constructed so as to be elongate in a transverse direction. In particular, the oil separation member does not have to be constructed in a rotationally symmetrical manner and it can also have a planar extent which is elongate in a transverse direction. The redirection member may have alternatively to a flow tip a flow edge which is located in the transverse direction. Consequently, the oil separation member is elongate in the direction of the longitudinal axis and is formed in particular in a funnel-like manner, wherein the funnel-like shape is constructed to be open counter to the flow direction of the gas flow.
According to still another variant, the tubular oil separation member may again be constructed from a nonwoven material and may be located with a substantially constant outer diameter in a first portion of the hollow member which has a smaller diameter so that no gap or only a very small radially extending gap is present between the oil separation member and the inner side of the hollow member. As a result, the inner side of the hollow member forms an impact face for a gas flow which travels through the oil separation member and for oil present therein at least in the front region at the flow side.
In this instance, the hollow member may be constructed downstream so as to have a second portion having a greater diameter or having at least one lateral expansion so that the inner side of the hollow member does not adjoin the outer side of the oil separation member and does not form an impact face, whereby throughflow of the oil separation member with the gas flow can be improved in this partial region.
The variants of the oil separator set out above are constructed in such a manner that the gas flow is redirected only radially outward or partially also inward again without a torsion or a flow component which would be directed about the longitudinal axis of the oil separator being introduced into the gas flow. The advantage is thereby afforded that the gas flow is subjected during flow through the oil separator to a smaller pressure decrease than in the case of introduction of a torsion in the gas flow, as known from the prior art. The torsion-free guiding of the gas flow through the oil separator is particularly based on the construction of the redirection member as a rotation member or as a member which is planar in a transverse direction and which limits the redirection of the gas flow to radial and axial flow components.
Additional steps which improve the invention are set out in greater detail below together with the description of a preferred embodiment of the invention with reference to the Figures, in which:
At a first side, a gas flow 13 which is charged with oil 12 can be introduced into the hollow member 11 and there is located at the side of the gas introduction an inlet funnel 20 which extends as far as the inner side of the hollow member 11. Thus, the gas flow 13 is completely introduced into the inlet funnel 20, whereby the gas flow 13 accelerates in the direction toward the longitudinal axis 10. A retention member 18 adjoins the inlet funnel 20 and a redirection member 15 is located downstream of the retention member 18 and has a flow tip 16 which is directed counter to the flow direction of the gas flow 13 and which is located in the longitudinal axis 10. In this instance, the redirection member 15 extends in a rotationally symmetrical manner about the longitudinal axis 10 and there adjoins the flow tip 16 a redirection contour 17 which has in a downstream direction an increasing diameter, wherein the increase of the diameter forms, for example, a hyperbola-like redirection contour 17. The gas flow 13 which is accelerated by the inlet funnel 20 strikes the redirection member 15 with the redirection contour 17 and is radially redirected outward.
Furthermore, an oil separation member 14 which is constructed in a funnel-like manner is located in the hollow member 11 and the funnel-like shape opens counter to the direction of the gas flow 13. The oil separation member 14 is located in this instance in the longitudinal axis 10 in such an axial position that the redirection member 15 is located approximately in the rear third in the oil separation member 14. In an upstream direction, the retention member 18 which is constructed with radial gaps 19 adjoins the redirection member 15. The gas flow 13 which strikes the redirection member 15 is guided through the radial gaps 19 of the retention member 18 by the radially outwardly directed redirection by the redirection contour 17 and, as a result of the radial redirection of the gas flow 13, it strikes the inner side 14a of the oil separation member 14 which is formed from a nonwoven material.
A peripheral radial gap extends between the retention member 18 and the inner side 14a of the oil separation member 14 so that the gas flow 13 can flow round the redirection member 15 and can continue to flow downstream through the central passage through the oil separation member 14.
An opening funnel 21 which acts as a diffuser and by which the pressure loss is minimized during flow through the oil separator 1 with the gas flow 13 adjoins the oil separation member 14. After a passage of the gas flow 13 through the retention member 18, after the redirection member 15 is flowed round and after striking the inner side 14a of the oil separation member 14, the gas flow 13 is purged of the oil 12 during the continuing travel through the opening funnel 21 so that the cleaned gas flow 13′ can be supplied to the air intake tract of the internal combustion engine. The separated oil 12 can subsequently be supplied again to the oil circuit of the internal combustion engine via separation openings (not shown) in the hollow member 11.
The views of
A flow cross-section region 24 which is formed substantially over the entire periphery around the flow guiding member 22, irrespective of the retention ribs 23, is formed between the outer side of the flow guiding member 22 and the inner side 11a of the hollow member 11. The gas flow 13 is accelerated by the flow guiding member 22 into the flow cross-section region 24 and the accelerated gas flow 13 subsequently strikes an oil separation ring 25 which is connected upstream of a subsequent additional oil separation member 14. The oil separation ring 25 has a rear-side carrier ring 26, against which the oil separation ring 25 is supported, wherein the oil separation ring 25 is formed from a nonwoven material and forms a first separation stage.
As a result of the gas flow 13 striking the oil separation ring 25 comprising nonwoven material, there is produced an impactor effect so that droplets of the oil 12 are already separated by the impactor effect at the oil separation ring 25. The separated oil 12 can travel along the inner side 11a in a downstream direction through corresponding recesses between the carrier ring 26 and the inner side 11a of the hollow member 11 in order subsequently to reach a separation opening (not shown) in order to direct the oil 12 out of the hollow member 11.
The gas flow 13′ redirected by the impactor effect passes through the oil separation ring 14 through an inner passage, wherein the gas flow 13′ is already pre-cleaned. The pre-cleaned gas flow 13 is subsequently brought via an intermediate element 27 into operational influence with the redirection member 15 and the gas flow 13′ is redirected by the redirection member 15 against the oil separation member 14. The intermediate element 27 has radial gaps 19, through which the gas flow 13′ reaches the inner side of the additional oil separation member 14 which is formed in a tubular or sleeve-like manner. The redirection of the gas flow 13′ radially outward is brought about by the redirection member 15 which has at the front side a redirection tip 28 and the redirection tip 28 is followed by a substantially hyperbola-like member shape of the redirection member 15 which extends in a rotationally symmetrical manner about the longitudinal axis 10 and which is formed in an integral manner with the intermediate element 27.
The gas flow 13′ which reaches the inner side of the oil separation member 14 is subjected to an additional impactor effect, whereby an additional separation effect of droplet-like oil 12 is achieved so that finally the gas flow 13′ which is discharged from the oil separator 1 at the right-hand side is cleaned in a particular manner.
The additional oil separation member 14 may also comprise a nonwoven material and the pre-cleaned gas flow 13 can simply flow against the inner side of the oil separation member 14 or even also flow through the oil separation member 14 at least with a partial gas flow. The separated oil 12 can subsequently be discharged via an oil discharge opening which is not shown.
The carrier ring 26 is constructed by way of example in one piece with the intermediate element 27 and the intermediate element 27 has retention walls 29 which extend in the flow direction and by which the additional oil separation member 14 can be retained against the inner wall of the hollow member which is not shown in greater detail. Consequently, a spacing between the radial gaps 19 in the intermediate element 27 and the oil separation member 14 is maintained so that the inner side of the oil separation member 14 can be subjected to flow by the gas flow 13.
At the outer side of the carrier ring 26, there are shown recesses 30 through which oil 12 which has already been separated from the gas flow 13 by the first oil separation ring 25 can continue to be directed at the outer side of the oil separation member 14.
The nonwoven material of the oil separation member 14 does not necessarily have to touch the inner wall of the hollow member 11 but instead a gap between the outer peripheral face of the nonwoven material and the inner peripheral face of the hollow member 11 may be provided in order to promote a discharge of oil droplets.
At the inner side in the intermediate element 27, there is formed the redirection member 15 which does not have a flow tip, as in
The embodiment of the planar oil separator 1 has a structure and a function as already described above in connection with the embodiment of
The oil separation member 14 is located along the longitudinal axis 10 in an axial position upstream of the redirection member 15 so that the redirection member 15 is located downstream of the oil separation member 14 and the gas flow 13, upstream of the redirection member 15, is directed thereby through the radial gaps 19 at or through the oil separation member 14. The separation of the oil 12 is carried out for a weak and for a powerful flow of the gas flow 13 as already described in connection with
The views of
Finally,
In order to redirect the gas flow 13, there is formed at the inner side in the intermediate element 27 a redirection member 15 which is flowed against by the gas flow 13 from the direction of the longitudinal axis 10 and by which the gas flow 13 is redirected radially outward in order to flow through the radial gaps 19.
The tubular oil separation member 14 is constructed from a nonwoven material and is located with a substantially constant outer diameter in a portion 11′ of the hollow member 11 which has a smaller diameter so that no or only a very small radially extending gap is present between the oil separation member 14 and the inner side of the hollow member 11. As a result, the inner side of the hollow member 11 forms an impact face for a gas flow 13 which travels through the oil separation member 14 and for oil 12 present therein.
In a downstream direction, the hollow member 11 is constructed to have a portion 11″ with a greater diameter or with at least one lateral expansion so that the inner side of the hollow member 11 does not abut the outer side of the oil separation member 14 and does not form an impact face, whereby in this partial region a throughflow of the oil separation member 14 with the gas flow 13 can be improved.
The construction of the invention is not limited to the preferred embodiment set out above. Instead, a number of variants which also make use of the solution set out in embodiments which are of different types in principle are conceivable. All the features and/or advantages which arise from the claims, the description or the drawings, including structural details or spatial arrangements, may be inventively significant both per se and in extremely varied combinations.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2013 106 334.9 | Jun 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2014/001645 | 6/17/2014 | WO | 00 |
