EP2558690B1 - Oil mist separator of a crankcase ventilation device of an internal combustion engine - Google Patents

Description

The present invention relates to a Ölnebelabscheider a crankcase ventilation device of an internal combustion engine, with a separator housing, with a raw gas from the crankcase of the internal combustion engine in a Rohgasbereich the separator leading raw gas duct, with a clean gas from a clean gas region of the separator discharging clean gas duct and with a separated from the crankcase ventilation gas in oil the crankcase of the internal combustion engine recirculating oil return passage, in the course of which a valve is arranged, which opens the oil return passage falls below a predetermined pressure difference between the two sides of the valve.

An oil mist separator with the features indicated above is made US Pat. No. 6,907,869 B2 . US 2001/054418 A1 . FR 2932843 A1 and DE 100 2006 018783 known. The arranged in the course of the oil return passage valve here is a check valve, which is preferably located near the crankcase of the internal combustion engine, ie from the oil mist separator, to open the valve by the pressure of the oil collected upstream of the valve against the pressure prevailing in the crankcase gas pressure and then drain the oil from the oil return passage in the crankcase of the engine. Furthermore, it is optionally provided in this known oil mist separator that a condensate return passage leads parallel to the oil return passage to the crankcase of the internal combustion engine from the deepest in use position range of the raw gas channel, wherein the condensate return passage is performed without a valve or a siphon.

A disadvantage is considered in this known Ölnebelabscheider that an increase of oil from the crankcase forth in the oil return passage, which can happen at unfavorable pressure conditions, a disturbing entry of oil in the raw side of the oil mist can not be safely excluded. One second disadvantage of this known oil mist separator is seen in the fact that it requires in its design with condensate return from the Rohgaskanal two separate lines, namely a first line for the oil return passage and a second line for the condensate return passage from the separator housing to the crankcase. As a result, a high installation effort when connecting the Ölnebelabscheiders is caused to the associated internal combustion engine.

For the present invention, therefore, the object is to provide an oil mist separator of the type mentioned, which avoids the disadvantages mentioned and with the one hand, a reliable and trouble-free operation is ensured even under unfavorable pressure conditions and on the other hand, a reduced installation effort is achieved.

The solution of this object is achieved according to the invention with a Ölnebelabscheider of the type mentioned, which is characterized in that the valve as a valve body has a floating body whose density is smaller than the density of oil and by a rising from the crankcase ago oil level in the oil return channel in his Closed position against a valve seat can be raised, and that the weight of the valve body and the dimensions of the valve body surrounding the valve channel are coordinated so that upon reaching a predetermined speed of a gas flow in the valve passage in the direction of the crankcase to the separator housing the valve body by the gas flow and on the gas pressure difference acting on the valve body in its closed position against the valve seat can be raised.

The invention provides an oil mist separator whose valve combines two valve functions, namely the function of a float valve and the function of a check valve. The function of the float valve always comes into play when, due to unfavorable pressure conditions, oil is forced out of the crankcase of the internal combustion engine through the oil return channel upwards in the direction of the separator housing. As soon as the rising oil level reaches the valve body, it floats on the oil and is thereby brought into sealing contact with its valve seat, whereby the valve closes. Thus, oil from the crankcase at most to the valve, but not further, in particular not in the clean gas region of the separator, get. The function of the check valve always comes into play when passing through the oil return channel Gas from the crankcase flows towards the separator housing of the oil mist separator. By a suitable vote of the weight of the valve body and the dimensions of the valve body surrounding the valve channel ensures that upon reaching a predetermined gas velocity in the valve channel and due to a gas pressure difference caused thereby on the two sides of the valve body this is raised and placed in sealing contact with its valve seat , Thus, an undesirable gas flow from the crankcase through the oil return passage in the separator housing is at least largely prevented with the same valve. With a suitable choice of the aforementioned parameters, even a low gas velocity can ensure the desired closing of the valve. Since only a single valve is required to achieve the two valve functions, advantageously only a correspondingly low parts and assembly effort is required. At the same time, due to its dual function, the valve ensures a particularly high operational reliability of the oil mist separator, which contributes to compliance with relevant emission limit values of the associated internal combustion engine.

A preferred embodiment of the oil mist separator provides that the valve body is a hollow ball and that the valve channel surrounding the valve channel is round in cross-section and forms a radial annular gap with the valve body in its open position. In this embodiment, the valve body is functionally independent of position, which contributes significantly to reliable operation. In addition, this results in a symmetrical loading of the valve body when it is flowed by gas from the crankcase, which contributes to a safe operation of the valve as a check valve.

Since the valve in the oil return passage opens only in the presence of suitable pressure conditions, in particular when the associated internal combustion engine is at a standstill, an oil collecting space is expediently formed upstream of the valve in the separator housing. The volume of the oil collection chamber should be selected according to the requirements in order to ensure the absorption of a sufficient amount of oil for all conceivable operational situations.

From the relevant practice, it is known that in the course of leading from the crankcase of the internal combustion engine to the oil mist separator raw gas channel, in particular as a result of cooling and / or flow deflection, condensate reflected. To relieve the Ölnebelabscheider of this condensate, it is, as already mentioned above, known to lead a condensate return passage of a running in operation of the oil mist separator deepest point of Rohgaskanals to the crankcase of the internal combustion engine, but this is associated with the disadvantage of an additional line. In order to avoid its own condensate return line from the oil mist separator to the crankcase, the invention proposes that a condensate return duct branches off from a operating point of the oil mist separator deepest point of the Rohgaskanals and that the condensate return duct downstream of the arranged in the oil return passage, first valve opens into the oil return passage. Advantageously, so that the oil return channel is also used for the return of the condensate from the raw gas channel, so that a single line is sufficient as a combined oil and condensate return from the oil mist separator to the crankcase. This simplifies the connection of the Ölnebelabscheiders to the associated internal combustion engine and reduces the number of necessary items.

In a further embodiment, it is proposed that in the condensate return duct, a second valve is arranged, which opens the condensate return duct falls below a predetermined pressure difference between the two sides of the second valve. This ensures that the condensate collected before the second valve is discharged into the crankcase only in the presence of suitable pressure conditions, in particular when the associated internal combustion engine is at a standstill. An undesirable, disturbing gas flow through the condensate return duct against the condensate flow direction is avoided by the second valve.

In particular, to achieve a compact design and a cost-effective production is further proposed that the condensate return channel and the mouth of the condensate return channel in the oil return passage and possibly arranged in the condensate return passage second valve are integrated into the separator housing.

Since the second, arranged in the condensate return valve, as well as the first valve in the oil return passage, only in the presence of suitable pressure conditions, especially at standstill of the associated internal combustion engine opens, is expedient upstream of the second valve in the separator housing a condensate collecting space educated. Herein condensate can accumulate without disturbing the function of the oil mist separator until it is discharged by opening the second valve.

In order to connect the oil mist separator for the purpose of oil and condensate return as simple as possible with the associated internal combustion engine, it is preferably provided that viewed in the oil flow direction downstream of the first valve portion of the oil return channel is formed as protruding from the separator housing hose or pipe connection piece. At the connecting piece then a flexible hose or a stable pipe can be connected with little effort, the other end is connected to the crankcase of the associated internal combustion engine.

The oil mist separator according to the present invention can be made variously and practically arbitrarily in terms of the means or mechanisms employed therein for separating oil mist from the crankcase ventilation gas. In a first preferred embodiment in this respect, it is provided for the oil mist separator according to the invention that at least one fibrous or nonwoven body is arranged as a separating element in the separator housing. With such a separation element, effective separation of oil mist from the crankcase ventilation gas is ensured. At the same time, such separation elements are able to dissipate and discharge the oil deposited therein under the action of gravity so that a long operating time is achieved before the separation element has to be replaced by a new element. In a second preferred embodiment, it is provided that a rotatably drivable rotor is arranged as a separating element in the separator housing. Even with such an active separation element, effective separation of oil mist from the crankcase ventilation gas is ensured, and as a rule, a rotor advantageously has a longer life in comparison with a fiber or nonwoven body, or even a lifetime component of the precipitator which never has to be renewed. In a preferred further alternative, the separation element can be formed by at least one cyclone.

Finally, the invention proposes that the separator housing is made in one piece with the exception of a top, removable cover or composed of several interconnected, such as welded or glued or latched, items composed. A one-piece design is special inexpensive injection-molded plastic. An embodiment of several, preferably as few as possible, individual parts is still inexpensive to manufacture and also allows such geometric designs that are not integrally represented. The removable lid allows easy replacement of a separating element during maintenance of the oil mist separator.

Figur 1

einen Ölnebelabscheider in einer ersten Ausführung in einem Teil-Längsschnitt durch seinen unteren Bereich,

Figur 2

einen vergrößerten Ausschnitt aus dem Ölnebelabscheider gemäß Figur 1 im Bereich zweier Ventile, in einem ersten Betriebszustand, im Längsschnitt,

Figur 3

den gleichen Ausschnitt wie Figur 2, in einem zweiten Betriebszustand, ebenfalls im Längsschnitt, und

Figur 4

den Ölnebelabscheider in einer zweiten Ausführung, wieder in einem Teil-Längsschnitt durch seinen unteren Bereich.

In the following an embodiment of the invention will be explained with reference to a drawing. The figures of the drawing show:

FIG. 1

a Ölnebelabscheider in a first embodiment in a partial longitudinal section through its lower portion,

FIG. 2

an enlarged section of the oil mist according to FIG. 1 in the region of two valves, in a first operating state, in longitudinal section,

FIG. 3

the same section as FIG. 2 , in a second operating state, also in longitudinal section, and

FIG. 4

the oil mist separator in a second embodiment, again in a partial longitudinal section through its lower portion.

FIG. 1 shows in a partial longitudinal section a first oil mist separator 1 with a separator housing 10 and a separating element 11 arranged therein. The separating element 11 separates the interior of the oil mist separator 1 into a raw gas region 11.1 and a clean gas region 11.2. In the illustrated embodiment, the separation element 11 consists of a hollow cylindrical fiber or nonwoven body, which can be removed during maintenance of the oil mist separator 1 from the separator housing 10 and replaced by a new separation element 11. At his in FIG. 1 not visible top is to the separator housing 10 is closed by a removable lid.

The separator housing 10 comprises a in FIG. 1 only partially visible upper housing part 10.1, in which the separating element 11 is arranged and fixed. Downwards closes to the upper housing part 10.1 a lower housing part 10.2 to which side, in FIG. 1 to the left, merges into a nozzle part 10.3, which contains a raw gas channel 12. The nozzle part 10.3 is designed here as a hose connection piece, to which a crankcase ventilation gas supplying hose can be connected.

At the bottom of FIG. 1 is as part of the separator housing 10 finally a return duct part recognizable 10.5, which is connected from below with the lower housing part 10.2, for example, welded, is. The return duct part 10.5 contains an oil return duct 14 and a condensate return duct 15 opening into the oil return duct 14. Towards the bottom, the oil return duct 14 merges into a connecting pipe 19, to which an oil and condensate can be connected to the oil sump or the crankcase of the associated internal combustion engine.

Radially outside of the separation element 11 is located in the separator housing 10, an oil collecting gutter 10.4, the at least one in FIG. 1 invisible connection opening is connected to a right in the housing lower part 10.2 provided oil collecting space 16. The oil collection chamber 16 goes down into an oil return passage 14, in the course of which a valve 2 is arranged.

From the deepest in installation position of the oil mist separator 1 region of the raw gas channel 12 is a condensate return channel 15 down from which downstream, ie below, the valve 2 opens into the oil return passage 14 at the junction 18. In the course of the condensate return channel 15, a further, second valve 3 is arranged.

During operation of the oil mist separator 1, this crankcase ventilation gas, which is charged with oil mist and is supplied through the raw gas duct 12 from the crankcase of an associated internal combustion engine, first passes into the raw gas region 11.1 located in the interior of the separation element 11. From there, the gas flows through the separation element 11 in the radial direction from the inside to the outside and enters as a cleared of oil mist clean gas in the clean gas area 11.2 radially outside of the separation element 11 a. From there, the clean gas is discharged via a clean gas channel not visible in the drawing, usually in the intake tract of the internal combustion engine.

The separated in the separation element 11 from the gas flow oil passes under gravity within the separation element 11 down and passes from the separation element 11 into the oil collection channel 10.4 over. From the oil collecting channel 10.4, the separated oil continues to flow under gravity into the oil collection chamber 16 and collects in this. Another flow of the oil is prevented here in the operation of the associated internal combustion engine, because the valve 2 assumes its closed position in the oil return passage 14, in which its valve body 20 bears sealingly against the associated valve seat 21. This closed position assumes the valve 2 under two conditions, namely a) when there is a gas pressure difference between the two sides of the valve 2, which is able to lift the designed as a hollow ball, correspondingly lightweight valve body 20 and into contact with the valve seat 21st or b) when oil in the oil return passage 14 from the crankcase of the associated internal combustion engine rises up to the valve 2 and the hollow ball forming the valve body 20 floats on the oil and is brought into abutment with the valve seat 21. The valve 2 thus combines in itself the functions of a check valve and a float valve.

The valve 3 in the condensate return channel 15 is designed here as a mushroom valve with a valve body made of an elastomer. Also, the valve 3 is during operation of the associated internal combustion engine in its closed position, so that in the raw gas channel 12 already precipitated condensate in the condensate return passage 15 and the valve 3 upstream condensate collection chamber 17 collects.

If appropriate pressure conditions on both sides of the two valves 2 and 3 are present, which is the case especially when the associated internal combustion engine, open the two valves 2 and 3. In the open state of the valves 2 and 3 on the one hand, the oil collected in the oil collection chamber 16 via the valve 2 and on the other hand, the condensate collected in the condensate collecting space 17 via the valve 3 and the condensate return passage 15, wherein the two streams downstream of the valves 2 and 3 are combined in the oil return passage 14 and fed through this the oil pan or the crankcase of the internal combustion engine. The opening of the valves 2 and 3 is assisted by the hydrostatic pressure of the oil collected in the oil collecting space 16 or of the condensate collected in the condensate collecting space 17.

If the engine is put into operation again, then the resulting pressure conditions on the two sides of the valves 2 and 3 ensure that they again their in FIG. 1 take shown closed position.

FIG. 2 shows in an enlarged sectional view, also in longitudinal section, the two valves 2 and 3 in their closed state. The valve body 20 of the first valve 2 is formed by a hollow ball, so it has a low weight. The weight of the valve body 20 and the extent of the valve body 20 receiving valve channel 22 are coordinated so that at a certain, specifiable speed overflowing gas flow through the oil return passage 14 in the direction of the crankcase to Ölnebelabscheider, so according to the drawing from the bottom up, the gas flow and the force acting on the valve body 20 pressure difference on the valve body 20 exert a force sufficient to lift the valve body 20 and in the in FIG. 2 shown sealing system to bring the valve seat 21. At the same time, the hollow ball forming the valve body 20 is lighter than oil, so that it floats on an oil level that may rise through the oil return channel 14 and into the oil level FIG. 2 shown closed position, in which the valve body 20 abuts the associated sealing seat 21. An undesirable, the function of the oil mist separator disturbing gas flow against the flow direction of the returned oil in the oil return passage 14 is thus avoided, as well as an undesirable supply of oil from the crankcase through the oil return passage 14 into the oil mist.

The arranged in the condensate return passage 15, the second valve 3 is located in FIG. 2 also in closed position. In this position, the mushroom-shaped valve body 30 covers two valve channels 32, which connect the condensate collecting space 17 with the condensate return channel 15. If suitable pressure conditions are present, in particular if at standstill of the internal combustion engine on both sides of the valve 3, an equal pressure, in particular atmospheric pressure, is present, the weight of accumulated in the condensate collecting space 17 condensate in a position to deform the valve body 30 so that a condensate drain through the valve channels 32 is allowed past the valve body 30. In the example shown, the valve body 30 is an elastomeric body having a predetermined flexibility, elasticity and self-restoring force. For ease of assembly of the valve body 30 is in a valve channels 32 having wall within the housing base 10.2 locked. Instead of the mushroom valve, for example, a leaf or tongue valve can be used.

FIG. 3 shows in the same representation as the FIG. 2 the same section of the Ölnebelabscheider with the two valves 2 and 3, now the valve 2 is in its open position. In this open position, the valve body 20 is within the valve channel 22 downwardly away from the valve seat 21 and there is an annular gap 23 between the outer periphery of the valve body 20 and the inner circumference of the valve channel 22 free, through which an outflow of oil collected in the oil collection chamber 16 below Gravity effect down into the oil return passage 14 is made possible. In his in FIG. 3 shown open position, the valve body 20 is held by a not quantified stop, so that a further movement of the valve body 20 down is not possible.

The valve 3 is in FIG. 3 again shown in its closed position, the valve body 30 of the valve 3 assumes due to its own restoring force as soon as the condensate has flowed out of the condensate collection chamber 17 through the valve channels 32 and the valve body 30 is relieved of the weight of the condensate.

As the Figures 2 and 3 clearly show the confluence 18 of the condensate return passage 15 in the oil return passage 14 immediately downstream of the valve 2, whereby as early as possible, the streams of the recirculated oil and the condensate to be returned are combined. This results in a compact design with only one secondary return duct, namely the oil return duct 14, which also removes the condensate from the condensate collecting space 17 connected to the raw gas duct. The return channels 14 and 15 are formed in the return channel part 10.5, which is connected from below with the lower housing part 10.2, preferably welded, is.

The upper housing part 10.1, the lower housing part 10.2 and that return duct part 10.5 are in the example shown, the Ölnebelabscheiders 1 each one-piece injection molded parts made of plastic or die castings made of light metal, which allows cost-effective mass production.

FIG. 4 shows in a partial longitudinal section a second oil mist separator 1, also with a separator housing 10 and a separating element arranged therein 11. The separation element 11 consists in the second embodiment shown here of a rotatably mounted, rotatably drivable in a conventional manner rotor, which forms a Tellerstapelseparator. The separation element 11 in the form of the rotor is here as a rule a service life component of the oil mist separator 1 and must at most be removed from the separator housing 10 in the event of unexpected damage and replaced by a new separation element 11, ie by a new rotor. At his in FIG. 4 not visible top is to the separator housing 10 is closed by a removable lid.

In its other properties and functions corresponds to the oil mist separator 1 according FIG. 4 the embodiment described above according to the FIGS. 1 to 3 , whose description is referenced. <U> REFERENCE LIST: </ u> character description 1 Oil Mist Separators 10 separator 10.1 Housing top 10.2 Housing bottom 10.3 Stutz part 10.4 Oil collection trough 10.5 Return passage part 11 separating element 11.1 crude gas 11.2 Clean gas area 12 raw gas 14 Oil return passage 15 Condensate return duct 16 Oil collection chamber 17 Condensate collection space 18 Junction of 15 in 14 19 spigot 2 Valve in 14 20 valve body 21 valve seat 22 Valve channel of 2 23 annular gap 3 Valve in 15 30 valve body 32 Valve channels of 3

Claims (10)

1. An oil mist separator (1) of a crankcase ventilation device of an internal combustion engine, comprising a separator housing (10), a raw gas channel (12) conducting raw gas out of the crankcase of the internal combustion engine into a raw gas region (11.1) of the separator (1), a clean gas channel discharging clean gas out of a clean gas region (11.2) of the separator (1), and an oil recirculation channel (14) recirculating oil separated from the crankcase ventilation gas into the crankcase of the internal combustion engine, with a valve (2), which opens the oil recirculation channel (14) if a predeterminable pressure difference between the two sides of the valve (2) is no longer met, being arranged in the course of said oil recirculation channel,
   characterised in

   - that the valve (2) has a floating body as a valve body (20), the density of said floating body being lower than the density of oil and said floating body can be raised into the closed position thereof against a valve seat (21) by an oil level in the oil recirculation channel (14) that rises starting from the crankcase, and

   - that the weight of the valve body (20) and the size of a valve channel (22) enclosing the valve body (20) are matched to each other such that, when a predeterminable velocity of a gas flow is reached in the valve channel (22) in the direction from the crankcase to the separator housing (10), the valve body (20) can be raised against the valve seat (21) into the closed position thereof by the gas flow and a gas pressure difference acting on the valve body (20).
2. The oil mist separator according to claim 1, characterised in that the valve body (20) is a hollow sphere and that the cross section of the valve channel (22) surrounding the valve body (20) is round and forms a radial annular gap (23) with the valve body (20) in the open position thereof.
3. The oil mist separator according to claim 1 or 2, characterised in that an oil collecting chamber (16) is embodied upstream of the valve (2) in the separator housing (10).
4. The oil mist separator according to any one of claims 1 to 3, characterised in that a condensate recirculating channel (15) branches out from a position of the raw gas channel (12), which is lowest in operating position of the oil mist separator (1), and that the condensate recirculating channel (15) leads into the oil recirculating channel (14) downstream from the first valve (2) arranged in the oil recirculating channel (14).
5. The oil mist separator according to claim 4, characterised in that a second valve (3), which opens the condensate recirculating channel (15) when a predeterminable pressure difference between the two sides of the second valve (3) is no longer met, is arranged in the condensate recirculating channel (15).
6. The oil mist separator according to claim 4 or 5, characterised in that the condensate recirculating channel (15) and the junction (18) of the condensate recirculating channel (15) into the oil recirculating channel (14) and, if applicable, the second valve (3) arranged in the condensate recirculating channel (15) are integrated into the separator housing (10).
7. The oil mist separator according to any one of claims 5 or 6, characterised in that a condensate collection chamber (17) is embodied upstream of the second valve (3) in the separator housing (10).
8. The oil mist separator according to any one of claims 1 to 7, characterised in that a section of the oil recirculating channel (14) located downstream from the first valve (2), viewed in oil flow direction, is embodied as tube or pipe connecting piece (19), which projects from the separator housing (10).
9. The oil mist separator according to any one of claims 1 to 8, characterised in that at least one fibre or nonwoven body or a rotationally drivable rotor or at least one cyclone is arranged in the separator housing (10) as separating element (11).
10. The oil mist separator according to any one of claims 1 to 9, characterised in that, with the exception of an upper, removable lid, the separator housing (10) is embodied in one piece or is made up of a plurality of individual parts (10.1, 10.2, 10.5), which are connected to one another, for example welded or glued or locked.

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