EP2700791A1 - Oil separation assembly and cylinder head cover for a combustion engine - Google Patents

Abstract

The oil separator is comprised of a baffle wall (2) by which the blow-by gas (4) is directed. The direction of flow of the blow-by gas toward the baffle wall is directed and turned back at the baffle wall. The baffle wall is comprised of a grooved surface. The grooved surface is comprised of several grooves (3) which are at the depth of 0.5 mm. The ratio of groove spacing to groove width lies in the range between 0.5 and 1.5. The grooved surface is formed of multiple bars (7). The cross-section of the bars and the grooves are formed in triangular or rectangular.

Description

The invention relates to an oil separator assembly having the features of the preamble of claim 1 and a cylinder head cover having the features of the preamble of claim 15.

From the DE 103 20 215 B4 It is known to direct the flow direction of the blow-by gas of an internal combustion engine for oil separation on a baffle. At the baffle, the blow-by gas is deflected and deposited in this way particles and oil drops from the blow-by gas.

As a rule, the goal is to separate as many particles and oil droplets from the blow-by gas as possible. A major application of these oil separator arrangements is in the cylinder head covers of internal combustion engines.

There is always an effort to improve the known oil separator arrangements and cylinder head covers so that the described deposition is as effective as possible and, for example, as many particles and oil droplets can be separated from the blow-by gas. Improvements to the existing oil separator arrangements and / or cylinder head covers which are simply to be implemented in the design of existing cylinder head covers are particularly desirable.

The invention is therefore an object of the invention to provide a Ölabscheideranordnung and a cylinder head cover, in which the oil separation is improved with the simplest possible means to be converted.

The invention solves this problem with the features of the independent claims.

As the core of the invention, it is proposed that the baffle has a corrugated surface. The blow-by gas is directed to a baffle-equipped baffle and deflected at this. As a result, in particular larger particles can be impacted into the corrugated surface. These first adhere to the enlarged surface and then flow off.

The term corrugated surface comprises any particular periodic structure of alternating or spaced-apart elevations and / or depressions. Preferably, it is elongated elevations and depressions, which are preferably arranged parallel to each other, in particular alternately arranged webs and / or grooves. For example, comb-like structures are also included in the cross section.

The flow direction of the blow-by gas is therefore directed to the corrugated baffle. This means that the flow direction can be directed for example at a 90 ° angle perpendicular to the baffle wall, before the deflection takes place on the baffle. By "directed to the baffle wall", all such orientations are to be understood, in which the predominant direction-forming component is directed onto the baffle wall, ie flow directions which flow at an angle greater than 45 ° or less than 135 ° to the baffle wall.

Another advantage of the corrugated surface is the ease of implementation in existing systems. For example, if the design of a cylinder head cover is to be modified to include a baffle with a corrugated surface, this can be done by making comparatively small changes to the production tool.

Preferably, the corrugated surface is formed by a plurality of grooves. In the grooves, the particles are slowed down and then flow off together with the separated oil droplets.

The corrugations or the grooves are preferably arranged or aligned so that they extend in the direction of the extension direction of the cylinder head cover from the production tool. During the linear extension movement, for example, a corrugation with a triangular profile can be produced uniformly flat by a corresponding triangular profile on the production tool. The grooves are exactly in extension movement.

The basic geometry of proven cylinder head covers does not have to be laboriously changed, but the effectiveness of the oil separation can be appreciably increased by providing or modifying existing baffles with a corrugated surface.

In a preferred embodiment of the invention, the corrugated baffle is arranged in the flow path in front of a separation device. For example, in front of a by the blow-by gas automatically controlled spring tongue (hereinafter also referred to as Federzungenabscheider), or in front of a separation device in which in a vortex chamber in the flow direction helically rotating gas vortex flow is generated (hereinafter also referred to as Wirbelkammerabscheider). Accordingly, the oil separator preferably comprises a Federzungen- and / or Wirbelkammerabscheider. A corrugated baffle disposed in front of these separators serves for pre-separation and thus increases the effectiveness of the oil separator arrangement.

The gas outlet opening of the Wirbelkammerabscheiders is preferably disposed in the region of the outlet end of the vortex chamber, wherein in the vortex chamber due to the preferably tangential gas inlet, a rotating, helical gas vortex is induced, which extends from the gas inlet to the outlet end. For this purpose, the vortex chamber is expediently substantially cylindrically shaped, this term meaning a cross-sectionally rounded, for example oval or round, shape and comprising a cross-section changing over the length of the vortex chamber.

In another preferred embodiment of the invention, the corrugated baffle in the flow path behind one or more deposition devices, for example behind one of the above-mentioned Federzungen- and / or Wirbelkammerabscheider arranged. In this case, the blow-by gas strikes the corrugated surface after flowing through the separator and thereby separates further particles and / or oil droplets, whereby overall the effectiveness of the oil separator arrangement can be increased.

The Wirbelkammerabscheider is preferably uncontrolled, that is free of elements for the controlled change of the flow, in particular free of corresponding switching elements or valves. In particular, the vortex chamber has an open gas inlet and an open gas outlet opening.

In a further embodiment of the invention, a corrugated baffle wall is provided in combination in the flow path in front of and behind the separation device. In this way, the effectiveness of the separator can be further increased. Also more than two baffles are possible.

The oil separator assembly according to the invention is not limited to an arrangement in combination with a Federzungen- and / or Wirbelkammerabscheider, but can for example be used as a pre-separator or low-price oil separator without fine separation.

Fig. 1

eine isometrische Darstellung einer erfindungsgemäßen Ölabscheideranordnung;

Fig. 2

eine Ausschnittsdarstellung einer weiteren erfindungsgemäßen Ölabscheideranordnung;

Fig. 3

eine isometrische Darstellung eines geriffelten Prallwandabschnitts;

Fig. 4

eine Schnittzeichnung eines geriffelten Prallwandabschnitts;

Fig. 5

einen Schnitt durch einen Wirbelkammerabscheider;

Fig. 6

einen Längsschnitt durch einen Federzungenabscheider; und

Fig. 7

eine Schnittzeichnung eines geriffelten Prallwandabschnitts in einer weiteren Ausführungsform.

The invention will be explained below with reference to preferred embodiments with reference to the accompanying figures. Showing:

Fig. 1

an isometric view of an oil separator assembly according to the invention;

Fig. 2

a sectional view of another oil separator according to the invention;

Fig. 3

an isometric view of a corrugated baffle section;

Fig. 4

a sectional view of a corrugated baffle section;

Fig. 5

a section through a Wirbelkammerabscheider;

Fig. 6

a longitudinal section through a Federzungenabscheider; and

Fig. 7

a sectional view of a corrugated baffle section in a further embodiment.

The FIG. 1 shows a section of a cylinder head cover 1 of an internal combustion engine having an inventive oil separator assembly. The blow-by gas 4 of the internal combustion engine is deflected to a total of, for example, two fluted baffles 2. The corrugation is formed by a plurality of grooves 3. The flow of the blow-by gas 4 is marked with arrows in the illustration.

The deflection at the first impinged baffle 2 takes place about an axis transverse to the flow direction of the blow-by gas at an angle of preferably greater than 90 °, more preferably greater than 160 °. At this first corrugated baffle 2 is a pre-separation of particles and oil droplets from the blow-by gas 4. Due to the large deflection by more than 160 ° already a significant proportion of particles and oil droplets on the corrugated baffle 2 is deposited.

Subsequently, the blow-by gas 4 flows through a separator. In this case, the separation device can be, for example, a spring tongue (so-called spring tongue separator) controlled automatically by the blow-by gas 4, or a so-called vortex chamber separator, in which a gas vortex flow which helically rotates in the direction of flow is generated in a vortex chamber. For example, the separator may also be a cyclone separator with a dip tube. The separation devices typically have a flow channel 5.

After flowing through the separating device, the blow-by gas 4 is deflected a second time on a baffle 2 provided with a corrugation. Preferably, the flow direction of the blow-by gas 4 is deflected at this second baffle 2 by an angle greater than 45 °, more preferably greater than 80 °. By the deflection small and large particles, and oil droplets are deposited on the baffle 2, which were not previously deposited on the first corrugated baffle or on the separator.

The oil separator assembly in this preferred embodiment thus comprises two baffles 2, both preferably having a corrugated surface.

In the FIG. 2 a section of an oil separator according to the invention is shown. On a provided with grooves 3 baffle 2 flows blow-by gas 4, which has previously flowed through a separator. Two different separation devices are shown by way of example. Three juxtaposed Federzungenabscheider 9 and a Wirbelkammerabscheider. 8

In the Wirbelkammerabscheider 8, the helically rotating gas vortex flow of the blow-by gas 4 is indicated. The blow-by gas 4 is introduced through a tangentially directed inlet 10 into the Wirbelkammerabscheider 8 and rotates on the inside of the flow channel 5 helically in the longitudinal direction. The advantageous for the oil separator arrangement embodiment of Wirbelkammerabscheiders 8 is in the document DE 10 2007 046 235 A1 executed, the contents of which is included in the present application in this respect.

In the FIG. 5 is a section through a Wirbelkammerabscheider shown. A vortex chamber 13 is formed by a substantially tubular circumferential or peripheral wall 14. In the jacket wall 14, a gas inlet opening 12 is provided. To the gas inlet opening 12, a tubular gas inlet 18 is provided, which is arranged tangentially to the vortex chamber 13. The tubular gas inlet 18 produces a tangentially directed flow of the blow-by gas 4 entering the chamber 13 through the gas inlet opening 12. The gas flow entering through the gas inlet opening 12 is guided along the chamber wall 14. Due to the flow component in the longitudinal direction 21 arises in the chamber 13 a helically rotating about the longitudinal axis of the gas vortex 20, without additional guide devices such as baffles or the like are required. Helical means that the gas vortex forms at least one complete revolution, preferably at least two complete revolutions, in a medium load range of the engine. The rotating gas vortex 20 extends in total in a longitudinal direction 21 of the tubular chamber 13. The longitudinal direction 21 extends along the central axis of the chamber 13 and may therefore be composed in sections, such as from Fig. 5 is apparent.

The centrifugal forces acting on the oil particles in the gas vortex 20 cause a separation of the oil particles by contact with the peripheral wall 14 and coalescence of oil particles accumulating in the outer region of the chamber 13 to form oil droplets. The separated oil drains along the peripheral wall 14 of the chamber 13 and is returned by means of a return 24 in the engine oil circuit. In order to ensure the gravity drainage of the oil without dead spaces, the bottom of the chamber 13 in the operating position preferably has a steady gradient up to the oil drain line 24. By a backstop the entry of blow-by gas 4 is prevented in the clean room through the oil drain line 24 in the reverse direction.

After passing through the chamber 13, the helical gas vortex 20 exits at the outlet end 22 of the chamber 13, i. it enters a non-rotating flow and exits the chamber 13 through the gas outlet port 25 located at the outlet end 22 of the chamber 13. The cleaned blow-by gas 23 is then passed through a clean room, for example to the pressure control valve.

Due to the escape of the gas flow from the vortex chamber 13 at the outlet end 22 results in an open design of the chamber 13. In particular, an injection mold used in the manufacture of the oil separator 11 can engage through the gas outlet opening 25 in the chamber 13. For this purpose, it is advantageous if the cross-section of the chamber 13 between the near-inlet end 19 and the outlet end 22 has no taper, and that the surface of the gas outlet opening 25 is preferably greater than or equal to the maximum cross-sectional area of the chamber 13.

The open construction of the vortex chamber 13 allows the separated oil 27 to flow out of the vortex chamber 13 through the gas outlet opening 25 having a large cross section. As a result, an oil drainage with a small cross-section, which shows an unfavorable freezing behavior, can be avoided. In other words, the oil drain line 24 preferably discharges into the clean room and not into the vortex chamber 13.

Like from the FIG. 5 it can be seen finds at the outlet end 22 of the vortex chamber 13 according to the invention, in contrast to a cyclone with dip tube, no flow reversal of the gas in the opposite direction instead.

In a preferred embodiment, the vortex chamber 13 has two preferably parallel arranged, tangentially contacting partial chambers with a shared gas inlet for the formation of two counter-rotating, parallel gas vortexes; it is thus a double chamber. The gas inlet preferably takes place tangentially in the region of the tangential contact of the two sub-chambers and is preferably directed towards the middle of a web which serves as a flow divider. The sub-chambers are preferably (mirror) symmetrical to the gas inlet. The peripheral wall of the chamber is therefore preferably omega-shaped or ω-shaped. Compared to a vortex separator with only one gas vortex, the flow rate of the separator can be substantially doubled with a relatively small amount of space.

However, the configuration of the Wirbelkammerabscheiders is not limited to a certain number of gas vortices. Also included are embodiments with a gas vortex, as in the application DE 10 2007 046 235 A1 described. Embodiments with more than two parallel gas vortices are also conceivable.

Like in the FIG. 2 represented, for example, three Federzungenabscheider 9 can be arranged in addition to the Wirbelkammerabscheider 8. If the spring tongue of the Federzungenabscheiders 9 automatically releases an opening gap for the blow-by gas 4 due to the increased gas pressure against the spring bias, over a large volume flow range approximately linear or at least non-exponentially increasing transmission characteristic be achieved. In the spring tongue separator 9 preferably no helically rotating gas vortex is generated, which could cause a disproportionate or even exponential increase in the pressure loss at high flow rates. The advantageous for the oil separator arrangement embodiment of the Federzungenabscheiders 9 is in the publications DE 103 20 215 B4 respectively. DE 10 2007 058 059 A1 executed, the content of which is included in the present application in this respect.

The FIG. 6 shows a preferred embodiment of a Federzungenabscheiders 42. A spring tongue 41 is assigned to the Federzungenabscheider 42 and disposed substantially in the deposition chamber 43, and opens inwards. The spring tongue 41 is cantilevered at one end in a clamping device 45. The other end of the spring tongue 41 covers in the rest position, the gas inlet opening 46 of the oil separator 42, which may be circular, for example, from. The free end of the spring tongue 41 is acted upon by the oil-loaded blow-by gas. Due to the pressurization, the spring tongue 41 releases a gap 47, through which the blow-by gas flows at high speed into the downstream separation chamber 43.

In the deposition chamber 43, a baffle 48 is provided, which expediently has a predominantly vertical component with respect to the spring tongue 41 in the rest position and is preferably oriented approximately perpendicular to the spring tongue 41 in the rest position. Approximately perpendicular here means at an angle in the range of 70 ° to 110 °, preferably in the range of 80 ° to 100 °. The gas flow entering through the gap 47 thus runs approximately perpendicular to the baffle 48 and is deflected along the baffle 48. Due to the inertia of the Oil and dirt particles in the blow-by gas are deposited on the baffle 48. In order to obtain the highest possible separation effect, the gas flow is discharged through a downstream outlet chamber 44 such that a deflection of the gas flow in the opposite direction to the flow direction through the gap 47 into the separation chamber 43 takes place on the impact wall. The deflection of the gas flow is here preferably more than 120 ° and more preferably more than 150 ° to about 180 °, as shown Fig. 6 is apparent.

The deposited on the baffle 48 oil drains from the bottom 49 of the separation chamber 43 and the downstream outlet chamber 44 and is returned by means of the return in the engine oil circuit. In order to ensure the gravity drainage of the oil without dead spaces, the bottom of the chambers 43, 44 in the operating position preferably has a steady gradient up to the oil drainage.

In the Federzungenabscheider the arrangement of the spring-tongue valve at the gas inlet opening is essential because the cross-sectional constriction in the gap of the flexible tongue valve leads to a considerable acceleration of the flowing blow-by gas, which allows effective separation of oil particles on the rear wall arranged behind the baffle 48.

Like in the FIG. 2 is shown, both the Wirbelkammerabscheider 8 and the Federzungenabscheider 9 a flow channel 5. The flow channel 5 may be both closed and open in the longitudinal direction. In this embodiment, the flow channel 5 of the Wirbelkammerabscheiders 8 is closed in the longitudinal direction and the flow channels 5 of the Federzungenabscheider 9 in the longitudinal direction open, wherein the lower-side opening of the flow channels 5 in the illustration of FIG. 2 is not visible.

After flowing through the flow channel 5, the blow-by gas 4 exits from the outlet opening of the flow channel 5. Immediately behind a corrugated baffle 2 is arranged.

The distance D formed between the exit opening of the flow channel 5 and the corrugated surface is generally preferably less than 8 mm, more preferably less than 6 mm. In the arrangement of the corrugated baffle 2 behind a Federzungenabscheider 9, the distance D is preferably less than 2 mm, more preferably less than 1 mm. This comparatively small gap causes an increased separation of particles and oil droplets on the baffle 2.

The blow-by gas 4 ultimately exits the oil separator arrangement via a Gausaustritt 7.

The gas outlet 7 can also lead to other ventilation components, which are necessary for example for pressure or flow control.

A gas outlet 7 equipped with a pressure regulating valve is preferred for use in a diesel engine. For use in gasoline engines, a PCV valve (PCV = Positive Crankcase Ventilation) or a pressure control valve with or without combination with one check valve or multiple check valves can be provided.

Around or on a baffle 2 preferably Ölabtropfrippen can be arranged, collected over which the separated oil and then returned to the oil circuit. The return of the separated oil takes place for example via the oil return 6, which preferably has a check valve.

In the FIGS. 3 and 4 the corrugated surface forming grooves 3 are shown in detail.

The FIG. 3 shows the grooves 3 in isometric view, the FIG. 4 in a sectional view. Experience has shown that a number of dimensions and ratios for increasing the efficiency of the oil separator arrangement are advantageous, which are described below.

The grooves 3 have a depth t and are arranged next to one another at a distance d1. The width of the grooves 3 is referred to as d2. The groove depth t is preferably at least 0.5 mm, more preferably at least 0.75 mm, for example about 1 mm, with larger depths are conceivable. The grooves 3 are preferably arranged equidistantly next to each other

The groove spacing d1 and the groove width d2 are each preferably less than two, preferably less than one millimeter. The grooves 3 are preferably triangular in cross section.

The ratio of groove pitch d1 to groove width d2 is preferably in a range between 0.5 and 1.5, preferably in a range between 0.75 and 1.25. The ratio of groove spacing d2 to groove depth t is preferably in a range between 0.5 and 1.5, preferably in a range between 0.75 and 1.25. The ratio of groove width d1 to groove depth t is preferably in a range between 0.5 and 1.5, preferably in a range between 0.75 and 1.25.

The corrugation of the baffle 2 is not limited to triangular grooves 3. In general, each particular periodic structure of alternately or spaced apart, preferably elongated, preferably mutually parallel recesses 7 and / or elevations 3 (see FIG. 4 ). The shaping of the recesses 7 or elevations 3 in cross section is suitably selectable.

For example, comb-like structures are also included in cross-section, as in FIG FIG. 7 shown embodiment. Here, the corrugation is formed by parallel and alternately arranged webs 3 and grooves 7 formed therebetween. The webs 3 are rectangular, for example, in cross section. The width d1 of the webs 3 is preferably in the range between 1 mm and 3 mm. The distance d2 of the webs 3, or the width of the grooves 7, is preferably in the range between 1 mm and 2 mm. The height of the webs 3 or the depth t of the grooves 7 is preferably larger, more preferably at least twice as large as the width d1 of the webs 3, and is preferably in the range between 2 mm and 10 mm.

Claims (15)

Oil separator arrangement for an internal combustion engine with a baffle wall (2), along which flows blow-by gas (4), wherein the flow direction of the blow-by gas (4) is directed to the baffle wall (2) and on the baffle wall (2) is deflected, characterized in that the baffle wall (2) has a corrugated surface. Oil separator assembly according to claim 1, characterized in that the corrugated surface is formed by a plurality of grooves (3). Oil separator arrangement according to claim 2, characterized in that the groove depth t is at least 0.5 mm. Oil separator arrangement according to claim 2 or 3, characterized in that the ratio of groove spacing d1 to groove width d2 is in a range between 0.5 and 1.5. Oil separator arrangement according to one of claims 2 to 5, characterized in that the ratio of groove spacing d2 to groove depth t is in a range between 0.5 and 1.5. Oil separator arrangement according to one of claims 2 to 6, characterized in that the ratio of groove width d1 to groove depth t is in a range between 0.5 and 1.5. Oil separator arrangement according to one of the preceding claims, characterized in that the corrugated surface is formed by a plurality of webs (7). Oil separator arrangement according to one of claims 2 to 7, characterized in that the grooves (3) and the webs (7) in cross section are triangular or rectangular. Oil separator arrangement according to one of the preceding claims, characterized in that the flow direction of the blow-by gas (4) on the baffle wall (2) by an angle greater than 80 °, preferably greater than 160 ° is deflected. Oil separator arrangement according to one of the preceding claims, characterized in that at least one of the blow-by gas (4) automatically controlled spring tongue (41) in the flow direction before and / or after the baffle wall (2) is provided. Oil separator arrangement according to claim 10, characterized in that the blow-by gas (4) is introduced after flowing through the spring tongue (41) in a flow channel (5) which is directed to the corrugated surface. Oil separator arrangement according to one of the preceding claims, characterized in that the thickness of the gap D, which is formed between the outlet opening of a flow channel (5) and the corrugated surface, is less than 8 mm. Oil separator arrangement according to one of the preceding claims, characterized in that in the flow direction helically rotating gas vortex flow is generated before and / or after the blow-by gas (4) passes the baffle wall (2). Oil separator arrangement according to one of the preceding claims, characterized in that a plurality of baffles (2) with corrugated surface in the flow path of the blow-by gas (4) are provided. Cylinder head cover (1) for an internal combustion engine with an integrated oil separator arrangement according to one of the preceding claims.

Images