DE102011100239A1 - Bypass device for crank case venting system of internal combustion engine for motor car, has oil separation device whose coalescence element is provided between gas inlet and valve inlet of bypass valve in flow-technical manner - Google Patents

Abstract

The device (10) has a housing (12) formed with a bypass channel, which comprises a gas inlet (24) and a gas outlet (26) for crank case ventilation gas. A bypass valve (32) disconnects the gas inlet from the gas outlet. An oil separation device (58) separates oil from the ventilation gas. The oil separation device comprises a coalescence element (62) e.g. hollow cylinder, which is provided between the gas inlet and a valve inlet (64) of the bypass valve in a flow-technical manner. The coalescence element comprises a non-woven fabric, a mesh fabric, a granule and/or a wire arrangement.

Description

Technical area

The invention relates to a bypass device of a crankcase ventilation system of an internal combustion engine, in particular of a motor vehicle, comprising a housing with a bypass passage having a gas inlet and a gas outlet for crankcase ventilation gas, with a bypass valve which separates the gas inlet from the gas outlet, and with an oil separation device for the deposition of at least Oil from the crankcase ventilation gas.

State of the art

When operating internal combustion engines, it is known to produce crankcase ventilation gases as "blow-by gas" in the form of aerosol which flows from a combustion chamber into a crankcase of the internal combustion engine. In addition to products of complete or incomplete combustion, water and steam, soot and fuel residues, this gas also contains motor oil in the form of tiny droplets. In a closed vent, the gas flow from the crankcase is passed through a crankcase ventilation system and fed to the intake combustion air. With an open vent, the gas flow is released into the environment. In order to reduce the oil consumption by the discharged over the crankcase ventilation engine oil, an oil separator is provided in known internal combustion engines in the crankcase ventilation system. With the oil separator, the oil is separated from the crankcase ventilation gas. The separated oil is returned to the engine oil circuit of the internal combustion engine. In order to prevent impermissible overpressures or underpressures occurring in the crankcase under certain operating conditions, it is known to provide controllable bypass passages, so-called bypass passages, which are arranged parallel to at least the oil separator.

From the EP 1 285 152 B1 a device for deoiling crankcase ventilation gases of an internal combustion engine is known. The apparatus comprises an oil mist separator having a gas inlet connected to the crankcase, a gas outlet connected to the air intake tract and an oil outlet connected to the oil sump of the internal combustion engine. The device further comprises a controllable bypass channel for the oil mist separator. From a critical pressure drop at the oil mist separator automatically opens the bypass channel, so that the further increase in the differential pressure at an increasing volume flow of crankcase ventilation gas is not square but linear. A spring-loaded valve body in the bypass channel acts as a baffle plate. The flow gap can be adjusted via the valve spring depending on the differential pressure. As a result of flow deflection and impact separation, a de-oiling of the guided through the bypass duct crankcase ventilation gas is effected. When the bypass channel is open, however, the degree of separation in the device is lower than in the case of an oil mist separator without a bypass channel.

The invention has for its object to design a bypass device of a crankcase ventilation system of the type mentioned, in which the separation efficiency of at least oil from the crankcase ventilation gas with open bypass valve is as large as possible. In particular, the degree of separation should be as independent as possible of the opening degree of the bypass valve. In particular, a pressure drop in the bypass channel should be as low as possible when the bypass valve is open.

Disclosure of the invention

This object is achieved in that the Ölabscheideeinrichtung comprises a coalescing medium, which is arranged fluidically between the gas inlet and a valve inlet of the bypass valve.

Thus, according to the invention, a coalescing medium is provided which is suitable for separating even the smallest oil droplets from the crankcase ventilation gas. With the coalescence medium even the smallest oil droplets are captured from the oil mist of the crankcase ventilation gas and combined into larger oil droplets. With the coalescing medium, a high degree of separation is achieved even for very small oil mist droplets. The larger oil droplets can be easily collected. The collected oil droplets can be removed in particular via an oil outlet from the housing. Due to the fact that the coalescing medium is arranged in terms of flow before the valve inlet of the bypass valve, the oil mist is separated from the crankcase ventilation gas before it reaches the bypass valve and combined to form oil droplets. The degree of separation is thus almost independent of the degree of opening of the bypass valve.

In an advantageous embodiment, the coalescing medium can close the valve inlet tightly from the gas inlet. In this way, the crankcase ventilation gas is forced to flow through the coalescing medium. This has a positive effect on the degree of separation. Alternatively, the coalescing medium may also be arranged such that the crankcase ventilation gas flows against the coalescing medium and only partially flows through it. This can result in a reduction of the degree of separation.

Advantageously, the coalescing medium may define a cavity which is connected to the valve inlet. The coalescing medium can be designed in particular as a hollow cylinder, hollow cone or hollow cuboid. It may be designed in the manner of a basket, which is slipped over the valve inlet. On one side, the coalescing medium can be open towards the valve inlet. The crankcase ventilation gas can thus flow through the coalescing medium from outside to inside, whereby the oil mist is separated in the coalescing medium and even the smallest oil droplets are combined. The cleaned crankcase ventilation gas may flow separately from the oil to the cavity. The flow path of the cleaned crankcase ventilation gas may be substantially separate from the path of the separated oil. The separated oil can migrate along the coalescing medium. It can drain from this particular gravity. It can collect in a lower area of the housing. However, the separated oil may also be due to a suction generated by the flow of the crankcase ventilation gas through the bypass valve on the side facing the gas outlet side of the bypass valve. The oil passes as it was previously combined with the coalescing medium to sufficiently large drops, separated from the crankcase ventilation gas, so not as an aerosol, the bypass valve. The bypass valve therefore requires no oil separation. Alternatively, the coalescing medium can also be realized as a disk which covers the valve inlet and through which the crankcase ventilation gas has to flow.

Furthermore, advantageously, an axis of the coalescing medium can be arranged in parallel, in particular coaxially, to a valve axis of the bypass valve. In this way, the coalescing medium can be disposed in a fluidically favorable manner in front of the bypass valve. The coalescing medium can be flowed through from all sides evenly. This can have a positive effect on the oil separation efficiency. In addition, this can have a positive effect on a pressure loss on the coalescing medium. The surface of the flowing coalescing medium can be maximized with respect to the required installation space. It can be achieved a more uniform loading of the coalescer. The service life of the coalescence medium can thus be extended.

Advantageously, the coalescing medium can surround the valve inlet of the bypass valve in a circumferentially closed manner. Thus, the uniformity of the flow of the crankcase ventilation gas is further improved. The crankcase ventilation gas may flow circumferentially evenly distributed to the valve inlet.

In a further advantageous embodiment, the oil separation device may have a support body, in particular a support tube, for the coalescing medium. The support body can in particular have a shape-stabilizing function. In this way, a coalescence medium can be used which has a low inherent dimensional stability. With the support body can be prevented that the coalescent collapses, in particular due to pressure differences between its upstream side and its downstream side. Furthermore, the coalescing medium can be arranged in different spatial orientations with the support body. Preferably, the support body may be a support tube with passage openings for the crankcase ventilation gas. The support body may be open on the side where the cavity of the coalescing medium is connected to the valve inlet of the bypass valve. On the opposite side of the support body may be closed. With the support body, a cavity can be easily realized, which is limited by the coalescer with. The support body may be configured differently instead of a support tube. It can be realized in particular as a cuboid or cone with corresponding flow openings.

Advantageously, the coalescence medium may comprise a fleece and / or a screen mesh and / or a granulate and / or a wire arrangement. With a fleece, the coalescence medium can be built very dense. In particular, a high degree of separation of oil can be achieved. A sieve fabric has the advantage that the captured, even the smallest oil droplets can move along its fibers well. At nodes of intersecting fibers, the oil droplets can optimally unite to form larger drops of oil. The larger oil droplets can easily be removed from the coalescing medium and collected. In particular, they can drip off the coalescing medium. A wire arrangement can be easily realized. It does not absorb the oil. From him, the separated oil can be easily removed. Wiring arrangements are robust and can be easily cleaned.

Advantageously, at least one oil outlet of the housing for the separated oil in the flow direction of the crankcase ventilation gas may be arranged behind the bypass valve. Through this oil outlet, oil which passes through the bypass valve, be discharged from a local collecting space from the housing.

Alternatively or additionally, advantageously at least one oil outlet of the housing for the separated oil in the flow direction of the crankcase ventilation gas may be arranged in front of the bypass valve. From this oil outlet, oil which is discharged from the coalescing medium before it reaches the bypass valve, in particular drips off, can be drained from the housing.

Advantageously, an oil outlet may be provided both in front of the bypass valve and behind the bypass valve. Thus, oil discharged from the coalescing medium in front of the bypass valve as well as oil passing through the bypass valve can be easily removed from the housing.

Brief description of the drawings

Further advantages, features and details of the invention will become apparent from the following description, are explained in more detail in the embodiments of the invention with reference to the drawing. The person skilled in the art will expediently also individually consider the features disclosed in the drawing, the description and the claims in combination and combine these into meaningful further combinations. It show schematically

1 in section, a bypass module of a crankcase ventilation system of an internal combustion engine according to a first embodiment with a bypass valve shown there closed, a coalescing element upstream of this and an oil outlet in the flow direction behind the bypass valve;

2 the bypass module from the 1 with the bypass valve shown open here;

3 a detailed view of the open bypass valve from the 2 in a section III there;

4 a section of a bypass module according to a second embodiment, which to the bypass module according to the 1 to 3 is similar, here an oil outlet in the flow direction is arranged in front of the bypass valve;

5 the bypass module according to a third embodiment, which to the bypass modules from the 1 to 4 is similar, in each case an oil outlet is arranged in front of and behind the bypass valve.

In the figures, the same components are provided with the same reference numerals.

Embodiment (s) of the invention

In the 1 to 3 is a first embodiment of a bypass module 10 an otherwise not shown crankcase ventilation system of an internal combustion engine of a motor vehicle.

The bypass module 10 is arranged in a bypass line (bypass line), which is connected in parallel to an oil separator of the crankcase ventilation system of no further interest here. The oil separator aerosol a crankcase ventilation gas from blow-by gas from a crankcase of the engine is freed of oil. The separated oil is returned to the oil circuit of the internal combustion engine. With the oil separator, not only the oil but also other solid or volatile suspended matter contained in the aerosol are separated. When a limit pressure in the oil separator is exceeded, the blow-by gas is led through the bypass line.

The bypass module 10 includes a housing 12 , The housing 12 is from an inlet housing part 14 and an outlet housing part 16 assembled, which are separably connected. Between the inlet housing part 14 and the outlet housing part 16 there is a valve plate 18 , The valve plate 18 divided an interior of the housing 12 in an inlet chamber 20 and an outlet chamber 22 , The inlet chamber 20 is located in the inlet housing part 14 , The outlet chamber 22 is located in the outlet housing part 16 , In the inlet chamber 20 leads a gas inlet 24 for the crankcase vent gas flowing through the bypass line. The gas inlet nozzle 24 is outside the case 12 connected to a vent line of the crankcase, not shown. Via the vent line and the gas inlet nozzle 24 is to be cleaned crankcase ventilation gas (raw gas) at the limit pressure in the oil separator from the crankcase, the bypass module 10 fed. From the outlet chamber 22 leads a gas outlet 26 out. The gas outlet 26 is connected via a clean air line, not shown, with an intake air line of the internal combustion engine via which the purified crankcase ventilation gas (clean gas) is supplied to the combustion air.

Furthermore, an oil outlet 28 from the outlet chamber 22 out. The oil outlet 28 connects the outlet chamber 22 with a return line, not shown, for the separated oil, which leads to the oil circuit of the internal combustion engine. The bypass module 10 is spatially arranged so that the Ölauslassstutzen 28 located below.

The valve plate 18 has a valve opening 30 a bypass valve 32 on. The bypass valve 32 can also be referred to as a bypass valve. In the in the 1 shown resting state is a valve sealing surface 34 a valve body 36 of the bypass valve 32 close to a corresponding valve seat 38 at. The valve seat 38 surrounds the valve opening 30 on the outlet chamber 32 facing side.

The valve body 36 is located in the outlet chamber 22 , Its valve axis 40 runs coaxially to the valve opening 30 , On the valve opening 30 facing away from the valve body 36 a stamp 42 on. The Stamp 42 is in a housing-resistant sleeve 44 on the inner wall of the outlet housing part 16 Slidably mounted in the axial direction. In the sleeve 44 there is a helical compression spring 46 that are against the bottom of the sleeve 44 and against the valve body 36 supported. The bias of the coil spring 46 ensures that the valve body 36 at rest against the valve opening 30 is pressed and these tightly closes. About the bias of the coil spring 46 becomes an opening pressure for the bypass valve 32 specified.

On the valve opening 30 facing side, the valve body 36 four guide webs distributed in the circumferential direction 48 on which axially into the valve opening 30 protrude and a guide for the valve body 36 form.

On the inlet chamber 20 facing side are to the valve plate 18 an inner collar 50 and an outer collar 52 coaxial with the valve opening 30 arranged. The inner retaining collar 50 and the outer collar 52 extend in the axial direction. They limit one coaxial to the valve opening 30 circumferentially closed insertion groove 54 , The insertion groove 54 serves to receive a free edge of a support tube 56 a coalescing element 58 ,

The peripheral wall of the support tube 56 has a variety of gas-permeable openings 60 , At its the valve opening 30 opposite end face is the support tube 56 closed. On the peripheral side of the support tube 56 is radially outside a coalescing medium 62 arranged. In the coalescing medium 62 it is a fleece. The coalescing medium 62 extends over the entire circumference of the support tube 56 and is closed circumferentially. in the axial direction, it extends over the entire length of the support tube 56 , With its front edges it lies close to one end on the closed end side of the support tube 56 and at the other end in the insertion groove 54 on the valve plate 18 at. The coalescing medium 62 separates the gas inlet nozzle 24 close to a valve inlet 64 of the bypass valve 32 , An interior 66 of the coalescing element 58 passing through the support tube 56 is limited, is with the valve inlet 56 connected.

A bypass channel of the bypass module 10 , which is part of the bypass line, is formed by the gas inlet nozzle 24 , the inlet chamber 20 , the interior 66 of the coalescing element 58 , the valve opening 30 , the outlet chamber 22 and the gas outlet 26 ,

The housing 12 can be used for maintenance, for example for cleaning or replacing the coalescing medium 62 or the entire coalescing element 58 or for cleaning or replacement of the bypass valve 32 , to be opened by the inlet housing part 14 from the outlet housing part 16 is disconnected.

During operation of the internal combustion engine, the crankcase ventilation gas is usually passed through the oil separator, not shown, where the oil is deposited in a manner not further interesting here.

As the pressure drop across the oil separator increases, for example, as the gas flow increases and / or the oil separator passage decreases, for example because it is clogged, the pressure on the dirty side and thus also the pressure in the inlet chamber, decreases 20 of the bypass module 10 to. When the opening pressure of the bypass valve 32 is reached, the valve body 36 as in the 2 and 3 shown, axial to the valve axis 40 against the bias of the coil spring 46 from the valve opening 30 moved away. The bypass valve 32 will open this way. The crankcase ventilation gas flows into the bypass line and through the gas inlet port 24 , in 1 indicated by an arrow 68 , in the inlet chamber 20 into it. It flows through the coalescence medium 62 from radially outside to inside in the interior 66 , Smaller and larger oil droplets are doing on the fleece of Koaleszenzmediums 62 captured. Smaller oil droplets are combined to form larger oil droplets.

The clean gas released from oil flows from the interior 66 through the valve opening 30 through a gap 70 between the valve sealing surface 34 and the valve seat 38 through, into the outlet chamber 22 , It leaves the outlet chamber 22 through the gas outlet 26 in the direction of an arrow 72 to the clean gas line and the combustion air is supplied.

The through the coalescing element 58 separated oil droplets are due to the volume flow to the outlet chamber 22 transported and through the oil outlet 28 , in the direction of the arrow 74 , fed to the oil circuit

In the interior 66 of the coalescing element 58 the clean gas is separated from the oil. The clean gas is located in the interior 66 whereas the separated oil on the support tube 56 and on the coalescing medium 62 walks along.

In the 4 is a second embodiment of a bypass module 10 shown. The second embodiment differs from the first embodiment in that instead of the Ölauslassstutzens 28 an oil outlet 76 is provided, the bottom of the inlet chamber 20 of the inlet housing part 14 out leads. The oil outlet 76 is located below the coalescing element 58 , Through the oil outlet 76 becomes oil, which is on the coalescing element 58 is separated and combined from the crankcase ventilation gas and from the coalescing element 58 due to gravity dripping down, out of the inlet chamber 20 led out. The oil outlet 76 is analogous to the oil outlet 28 as in the first embodiment connected to the return line, so that the separated oil can be supplied to the oil circuit of the internal combustion engine.

In the 5 is a third embodiment of a bypass module 10 shown. In the third embodiment, both the Ölauslassstutzen 28 as in the first embodiment as well as the Ölauslassstutzen 76 as provided in the second embodiment. In this way, oil, which from the coalescer 58 dripped off, from the inlet chamber 20 be transported out. Also can be oil, which by valve opening 30 in the outlet chamber 22 get out of this led out. Both the oil outlet 76 as well as the oil outlet 28 are connected to the oil return line of the oil circuit.

In all embodiments of a bypass module described above 10 Among others, the following modifications are possible:
The invention is not limited to internal combustion engines of motor vehicles, but it can also be used for other types of internal combustion engines, such as industrial engines.

Instead of the nonwoven, it is also possible to provide a different coalescence medium, for example a sieve fabric, a granulate and / or a wire arrangement. It can also be provided a combination of different coalescing media.

Instead of a round support tube 56 It is also possible to use a different type of supporting body, for example a supporting cone or a supporting block.

The bypass valve 32 In addition, an adjusting device, for example an adjusting screw, having, with the bias of the compression coil spring 46 can be adjusted.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1285152 B1 [0003]

Claims (9)

Bypass device ( 10 ) of a crankcase ventilation system of an internal combustion engine, in particular of a motor vehicle, with a housing ( 12 ) with a bypass channel which has a gas inlet ( 24 ) and a gas outlet ( 26 ) for crankcase ventilation gas, with a bypass valve ( 32 ), which controls the gas inlet ( 24 ) from the gas outlet ( 26 ) and with an oil separator ( 58 ) for separating at least oil from the crankcase ventilation gas, characterized in that the oil separation device is a coalescing medium ( 62 ), which fluidly between the gas inlet ( 24 ) and a valve inlet ( 64 ) of the bypass valve ( 32 ) is arranged. Bypass device according to claim 1, characterized in that the coalescence medium ( 62 ) the valve inlet ( 64 ) close to the gas inlet ( 24 ) separates. Bypass device according to claim 1 or 2, characterized in that the coalescence medium ( 62 ) a cavity ( 66 ), which is connected to the valve inlet ( 64 ) connected is. Bypass device according to one of the preceding claims, characterized in that an axis of the coalescing medium ( 62 ) parallel, in particular coaxial, to a valve axis ( 40 ) of the bypass valve ( 32 ) is arranged. Bypass device according to one of claims 3 or 4, characterized in that the coalescence medium ( 62 ) the valve inlet ( 64 ) of the bypass valve ( 32 ) surrounds circumferentially closed. Bypass device according to one of the preceding claims, characterized in that the oil separation device ( 58 ) a support body, in particular a support tube ( 56 ), for the coalescence medium ( 62 ) having. Bypass device according to one of the preceding claims, characterized in that the coalescence medium ( 62 ) comprises a nonwoven and / or a screen fabric and / or granules and / or a wire assembly. Bypass device according to one of the preceding claims, characterized in that at least one oil outlet ( 28 ) of the housing ( 12 ) for the separated oil in the flow direction ( 68 . 72 ) of the crankcase ventilation gas behind the bypass valve ( 32 ) is arranged. Bypass device according to one of the preceding claims, characterized in that at least one oil outlet ( 76 ) of the housing ( 12 ) for the separated oil in the flow direction ( 68 . 72 ) of the crankcase ventilation gas in front of the bypass valve ( 32 ) is arranged.

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