EP1624162A1 - Method for venting the crankcase of an internal combustion engine and internal combustion engine for performing this method - Google Patents

Abstract

The crankcase is connected to at least one centrifugal separator integrated in the valve cap (3), cylinder head (4) and/or cylinder block of the internal combustion engine. All functional surfaces of the centrifugal separator are formed by already existing components of the internal combustion engine. A venting flow contaminated with oil is fed from the crankcase to the centrifugal separator as a result of a pressure gradient. The venting flow is fed tangentially so that oil is separated. The separated liquid components (15a,15b) are removed by gravity from the separator chamber (8a,8b), while the gas components (16a,16b) are evacuated from the separator chamber. An independent claim is included for an internal combustion engine.

Description

The invention relates to a method for venting a crankcase of an internal combustion engine, which has a cylinder block, a cylinder head and at least one cover, for example a valve cover.

Furthermore, the invention relates to an internal combustion engine for carrying out such a method, which has a crankcase, a cylinder block, a cylinder head, at least one cover, for example a valve cover, an engine mount, and an intake manifold as components.

A method of the above type is used to vent the crankcase and prevents the pressure that builds up in the crankcase during operation of the internal combustion engine, undesirably high values.

The piston of each cylinder of an internal combustion engine is axially movably guided in a cylinder tube and limits together with the cylinder tube and the cylinder head the combustion chamber of a cylinder. The piston crown forms part of the combustion chamber inner wall and seals together with the piston rings from the combustion chamber against the crankcase, so that no combustion gases or combustion air enter the crankcase and no oil enters the combustion chamber. For this purpose, the piston is equipped according to the prior art for receiving piston rings on its outer circumferential surface with annular grooves, wherein the piston rings extend almost over the entire circumference of the piston.

However, a complete sealing of the combustion chamber relative to the crankcase can not be ensured, so that a part of the combustion gases or the combustion air passes into the crankcase and there ensures an increase in pressure.

Part of the oil in the crankcase mixes in the form of a fine oil mist with the gases in the crankcase. This is supported by the crankshaft rotating in the oil sump of the crankcase, which contributes to additional foaming of the oil.

In order to reduce the pressure in the crankcase, the prior art method for venting the crankcase are used, the problem with the vent is in particular that the gases in the crankcase are contaminated with oil. Consequently, it is not expedient to provide the crankcase only with ventilation openings, via which a pressure equalization can take place. Rather, the venting stream leaving the crankcase must be separated from the liquid constituents present in the venting stream, in particular the oil. In this case, the separated and recovered oil is preferably returned to the crankcase, whereas the purified vent stream is preferably supplied to the intake tract of the internal combustion engine, in turn to participate in the combustion.

A method for venting the crankcase and an internal combustion engine for carrying out the method are described in EP 0 591 737 A1.

European Patent Application EP 0 591 737 A1 discloses an internal combustion engine having a crankcase and a cylinder head, the cylinder head being fixedly connected to the crankcase by means of cylinder head bolts. For this purpose, the cylinder head on through holes through which the cylinder head bolts are passed to be screwed into corresponding to the through holes tapped holes which are arranged in the crankcase, to be screwed.

For returning the condensed in the cylinder head or deposited oil collected in a chamber in the cylinder head, channels are provided in the cylinder head and in the crankcase, which run parallel to the through holes and the threaded holes and open into the crankcase. In this case, at least one channel for venting the crankcase, for which purpose this venting channel is connected by means of a connecting channel in the cylinder head with a through hole.

The vent channel directs the emerging from the crankcase and contaminated with oil venting stream through the through hole in a provided at the end of this through hole calming chamber in which a part of the oil is deposited, and then via another line in the intake manifold of the internal combustion engine to from there the Incineration to be supplied.

A disadvantage of the method for venting the crankcase described in EP 0 591 737 A1 is that the method is a passive method. That means that the separation of the gaseous and the liquid components of the venting stream is not actively supported, which is why the efficiency of the oil separation is low. The vent flow is effectively left to itself, with a separation of the oil is achieved only by utilizing fluidic effects. In this case, a part of the oil should precipitate on the walls of the vent line or condense in the settling chamber. As a result of the passive process, the vent flow supplied to the intake manifold is still highly contaminated with oil. The oil present in the bleed stream provides a noticeable increase in pollutant emissions when the bleed stream is sent to combustion and burns the oil.

A remedy here can be the use of an active separation device, which is to be provided as an additional unit. Such separation devices are, for example, oil separation systems, which according to the cyclone principle d. H. working with the use of centrifugal force. These Ölabscheidesysteme be arranged as an additional separate assembly on the internal combustion engine, the contaminated venting stream, the purified venting stream and the separated oil via lines, especially hoses, or the like communicate with the internal combustion engine.

A significant advantage of such active separation devices is the high efficiency in the purification of the vent flow d. H. during the recovery of the oil in the bleed stream. In addition, however, these separation devices also have a number of disadvantages, which will be briefly discussed in the following.

Due to the principle of the already costly separation device must be connected via hoses or the like to the internal combustion engine. This not only increases the cost but also the leakage susceptibility of the overall system comprising the separator and the internal combustion engine, since the hoses may become porous due to mechanical influences or as a result of an aging process.

In addition, the use of separate separation units and the use of hoses is inevitably associated with an increase in the interfaces at which different components must be connected to each other, which also increases the susceptibility to leakage of the entire system. The connection of the components is on the one hand due to the necessary fasteners and on the other hand due to the required assembly time to realize this connection costly.

Apart from the hoses to be provided, such separation systems are very complex and generally increase the number of components of the overall system, which increases the manufacturing costs. However, a high number of components also leads to high assembly costs, which are included in the manufacturing costs, and to an increase in weight of the entire system, which is always striving to conceive a solution concept of the lowest possible weight in terms of low fuel consumption.

The assembly time and thus the assembly costs increase - as already mentioned - with an increasing number of components. As the number of components increases, so does the likelihood of making mistakes in the fabrication of the individual components and in their assembly which may adversely affect the later functioning and life of the device.

Furthermore, separate d. H. external separation devices a comparatively high space requirement. But this high space requirement is the goal of the designers, in the engine compartment of the motor vehicle as effective as possible d. H. To realize dense packaging of the entire drive unit, contrary.

Against this background, it is the object of the present invention to provide a method for venting an internal combustion engine, with which the known from the prior art disadvantages are overcome, and which in particular compared to conventional methods on a high efficiency in the cleaning of the vent flow at only low cost.

Another object of the present invention is to provide an internal combustion engine for carrying out such a method, which is equipped with a crankcase, a cylinder block, a cylinder head, at least one cover, such as a valve cover, an engine mount, and an intake manifold as components, and in particular - in comparison with conventional internal combustion engines - has an optimized ventilation of the crankcase and at the same time has only a small additional space requirement.

The first sub-task is solved by a method for venting a crankcase of an internal combustion engine, which has a cylinder block, a cylinder head and at least one cover, such as a valve cover, in which the crankcase with at least one integrated in the internal combustion engine Centrifugal separator is connected so that a contaminated with oil vent flow is passed as a result of a pressure gradient from the crankcase to the centrifugal separator, and the vent flow of a separation chamber of the at least one centrifugal - is fed tangentially - to form a circular circulating flow, so that the liquid components contained in the vent flow , In particular, the oil, are deposited as a result of centrifugal force, and these separated liquid components are then separated from the gaseous components of the vent flow, on the one hand, the separated liquid components are discharged by utilizing the acceleration of gravity from the deposition chamber and evacuated on the other hand, the gaseous components from the deposition chamber become.

According to the invention, at least one centrifugal separator is integrated in the internal combustion engine, integration in the context of the present invention being understood and interpreted as meaning that the centrifugal separator is not externally d as a separate unit. H. is arranged as an additional accessory in addition to the internal combustion engine, but all functional surfaces of the centrifugal separator are formed by means of existing components of the internal combustion engine. How this is done in detail, will be described below in connection with the internal combustion engine according to the invention.

The integration of the centrifugal separator in the internal combustion engine offers several significant advantages.

On the one hand, an integrated centrifugal separator does not lead to an increased space requirement, so that the internal combustion engine according to the invention, together with the necessary ancillary components, is of the same construction volume in comparison to conventional internal combustion engines. This supports the aim of the designers, in the engine compartment of the motor vehicle as effective as possible d. H. to realize tight packaging of the entire drive unit.

The connection of the crankcase with the centrifugal separator can also be integrated into the internal combustion engine, so that supply lines, especially in the form of hoses, as required in conventional internal combustion engines with external separation devices are avoided. The leakage susceptibility of the entire system is thereby lowered significantly.

Furthermore, by this measure, the cost can be reduced, on the one hand, the manufacturing costs but also the assembly costs, in particular by reducing the number of components, are reduced.

The elimination of individual assembly operations also reduces the likelihood of errors in the assembly, which can adversely affect the subsequent functioning and lifetime of the entire system.

In addition, the inventive method has a high efficiency with respect to the cleaning of the vent flow, as with the centrifugal separator, an active separation device is used, which actively supports the separation or separation of the liquid components, in particular of the oil, from the gaseous components of the venting stream.

In this case, the contaminated with oil venting stream, which flows as a result of a pressure gradient from the crankcase to the centrifugal separator, the centrifugal separator or a so-called deposition chamber of the centrifugal separator is supplied tangentially. This forms a circular cyclone flow d. H. a circulating in the deposition chamber tangential flow, so that the liquid components contained in the vent flow, in particular the oil, are deposited due to the centrifugal force on the walls of the deposition chamber.

The venting stream is then separated into its two phases, namely on the one hand the liquid phase and on the other hand, the gaseous phase. Both phases can be removed separately from the separation chamber.

The inventive method thus the first object of the invention is based, that is to show a method for venting an internal combustion engine, with which the known from the prior art disadvantages are overcome, and which in particular a high efficiency in the cleaning of the venting stream under only low cost

Further advantageous variants of the method according to the invention are described in connection with the subclaims.

Embodiments of the method in which the at least one centrifugal separator is at least partially in the valve cover and / or the cylinder head are advantageous and / or the cylinder block is integrated, wherein the crankcase and the at least one centrifugal separator via a chain box and the valve cover are interconnected, so that the vent flow from the crankcase via the chain case and the valve cover is passed into the at least one centrifugal separator.

This variant of the method advantageously uses existing components to form the connection between the crankcase and centrifugal separator. In this case, on the one hand provided for covering the camshaft and the valve trains valve cover is used, which has the task from home to seal the said components and component groups oil-tight to the environment and to protect against contamination. The realized on the basis of these functions already in the valve bonnet technical characteristics, in particular the oil tightness are used according to the invention to direct the vent flow as free of leakage from the crankcase to the centrifugal, without the valve cover would have to be constructively changed in view of this additionally assigned their task.

The same applies in an analogous manner to the chain case used, which forms the first part of the compound, and - as the valve cover - components, namely the control drive camshaft, against the environment oil-tight and protects against contamination.

As a matter of principle, the chain case extends close to the crankcase, so that the vent flow can be conducted from the crankcase into the chain case and at the other end of the chain case in the area of the camshaft drive into the valve cover. From here it is fed to the at least one centrifugal separator.

For this purpose, the at least one centrifugal separator is at least partially integrated into the valve cover and / or the cylinder head and / or the cylinder block. The valve cover is usually a plastic part produced by the injection molding process, so that at least part of the functional surfaces of the centrifugal separator can be integrated by appropriate shaping in the valve cover already in the production of the valve cover. In a similar way functional surfaces can be incorporated into the cylinder head and the cylinder block, which are basically also castings. For this purpose, only corresponding molds or cores are required in the production, which can realize functional surfaces of the centrifugal separator.

This embodiment also offers advantages, because the centrifugal separator along a vertical d. H. can be arranged substantially in the direction of gravitational acceleration in the engine block, so that the separated oil can be discharged by utilizing the gravitational acceleration of the deposition chamber. In addition, the bleed stream can be used to lubricate the camshaft timing gear, camshaft and valve trains.

However, embodiments of the method are also advantageous in which the at least one centrifugal separator is at least partially integrated in the valve cover and / or the cylinder head and / or the cylinder block, wherein the crankcase and the at least one centrifugal separator via a riser, at least partially in the valve cover and / or the cylinder head and / or the cylinder block are connected to each other, so that the vent flow is passed from the crankcase via the riser into the at least one centrifugal separator.

In contrast to the previously described embodiment, the crankcase is connected by means of a riser with the at least one centrifugal separator. This riser is characterized by its short flow paths, which is particularly advantageous in cases where there is only a slight pressure gradient between the crankcase and centrifugal separator to promote the vent flow.

Embodiments of the method are advantageous in which the at least one centrifugal separator is connected by means of a line to a vacuum source in order to evacuate the gaseous constituents of the vent flow from the deposition chamber. This embodiment utilizes the fact that there is a negative pressure at several points in an internal combustion engine in operation. This vacuum is used to evacuate the gaseous components by connecting the deposition chamber to the vacuum source. There are no additional measures required to remove the gaseous phase of the vent flow to the separator. The promotion is due to a pressure gradient between the deposition chamber and vacuum source.

Embodiments of the method in which the at least one centrifugal separator is connected by means of a line to an intake tract of the internal combustion engine are advantageous in order to evacuate the gaseous constituents of the venting stream from the deposition chamber, wherein the line is preferably connected to the intake tract downstream of a throttle valve arranged in the intake tract becomes.

This embodiment of the method is advantageous because the gaseous phase is evacuated not only without further action as a result of an already prevailing pressure gradient, but also because the gaseous phase of the venting stream is fed together with additional combustion air or fresh fuel-air mixture combustion and disposed of advantageously in this way. This variant of the method is particularly advantageous because the oil contained in the vent flow can not be completely separated from the gaseous constituents, even when using an active precipitator, so that the gaseous phase of the vent flow has an unavoidable residual fraction of oil even after passing through the precipitator and thus unsuitable for being fired directly into the environment. A slight increase in pollutant emissions due to combustion of the oil is accepted.

Also advantageous are embodiments of the method in which a first valve is provided in the line to the vacuum source, with which the evacuation of the gaseous components from the deposition chamber is controlled.

By means of the valve, the line to the vacuum source, for example, be closed when the pressure gradient between the deposition chamber and vacuum source for a promotion of the purified vent flow is too low. A venting of the deposition chamber can thus be selectively controlled, but in particular also be laid on operating conditions in which a vent offers. If, on the other hand, the pressure gradient is too great, the flow resistance of the pipe can be increased with the aid of the valve.

The valve can also be closed in operating conditions in which an increased pollutant emissions due to oil combustion is undesirable. In addition, driving conditions or operating states of the internal combustion engine are conceivable in which a return flow starting from the negative pressure source in the direction of the deposition chamber is to be feared, as may occur, for example, during pushing operation.

For these reasons, embodiments of the method are advantageous in which the valve is opened when the pressure in the deposition chamber is higher than the pressure of the vacuum source, and the valve is closed when the pressure in the deposition chamber is lower than the pressure of the vacuum source.

Advantageous embodiments of the method in which a centrifugal separator is used, the deposition chamber tapers in the direction of a discharge opening for the liquid ingredients. The deposition chamber is preferably cylindrical in its basic form, which supports the circulating cyclone flow. The tapered portion of the chamber, on the other hand, is preferably in the shape of a truncated cone so that the radius of the tangential tangential flow steadily decreases as it enters the conical section, thereby increasing the centrifugal forces acting on the oil droplets still in the purge stream the efficiency of cleaning by additional deposits of oil further increased.

Advantageous embodiments of the method in which a centrifugal separator is used, which has a subsequent to the deposition chamber calming chamber. The settling chamber also serves as a reservoir for the separated oil and gives the opportunity with the oil in the settling chamber gaseous components of the venting flow to escape back into the deposition chamber.

Advantageous embodiments of the method in which the at least one centrifugal separator is equipped with a second valve, with which the discharge of the liquid components is controlled.

Advantageous embodiments of the method in which the second valve is opened when the pressure in the deposition chamber is higher than the pressure in the crankcase, and the second valve is closed, when the pressure in the deposition chamber is lower than the pressure in the crankcase.

Similar to the first valve already discussed above, which according to a preferred embodiment is provided in the line to the negative pressure source, unwanted backflows into the separation chamber or the centrifugal separator are thereby prevented.

It is advantageous - as mentioned - embodiments of the method in which the deposited in the at least one centrifugal liquid components are returned to the crankcase. By doing so, the oil loss in the crankcase, which inevitably sets by venting the crankcase due to the exiting vent flow, can be minimized by returning the recovered oil back to the crankcase.

The second sub-task on which the invention is based is achieved by an internal combustion engine which has a crankcase, a cylinder block, a cylinder head, at least one cover, for example a valve cover, an engine mount, and an intake tract as components, and which is characterized in that at least provided with a Abscheidekammer centrifugal separator is provided, which is integrated in such a way in the internal combustion engine, that all walls of the at least one centrifugal separator are formed by components of the internal combustion engine, wherein a first connection of the crankcase is provided with the at least one centrifugal separator, through which from the crankcase and contaminated with oil venting stream is passed into the at least one centrifugal separator to separate the liquid components and to separate from the gaseous components of the venting stream.

What has already been said for the method according to the invention also applies analogously to the internal combustion engine according to the invention. Reference is made in particular to the comments on the integration of the centrifugal separator and to the process characteristics per se, which characterize not only the method for venting, but also the operation of the internal combustion engine according to the invention.

For the formation of the functional surfaces of the at least one centrifugal separator are basically all components that are already present in a conventional internal combustion engine according to the prior art. In particular, the crankcase, the cylinder block, the cylinder head, covers of any kind, such as the valve cover, engine mounts, parts of the intake manifold or the oil filter housing and the like are suitable.

Preferably own manufactured by casting process parts. They offer the greatest potential for integration, whereby parts produced by injection molding as well as sand casting, but also parts produced by the so-called lost foam process, are suitable. In this case, the parting planes can be selected in an advantageous manner, which will become clear in connection with the description of the figures.

In connection with the description of the figures, the integration of the centrifugal separator and the components used for this purpose will be discussed in more detail, whereby the advantages of the internal combustion engine according to the invention are even better visible.

Embodiments of the internal combustion engine in which the at least one centrifugal separator is at least partially integrated in the valve cover and / or the cylinder head and / or the cylinder block are advantageous. The main advantages have already been mentioned in connection with the method according to the invention.

The valve cover is usually a plastic part produced by injection molding and the cylinder block and the cylinder head sand cast components, which is why these components include the above-mentioned - preferably to be used - components. However, they are also suitable for the formation of at least one centrifugal separator, because they allow the integration of the necessary channels in the internal combustion engine in addition to the integration of the separator, so allow training these channels without external supply lines, especially hose connections, would be necessary. This advantage, the functional integration, basically offer all components that are arranged between the crankcase and Einlasstrakt.

Embodiments of the internal combustion engine in which the crankcase and the at least one centrifugal separator are connected to one another by means of a chain box and a valve cover are advantageous, so that the vent flow from the crankcase can be introduced into the at least one centrifugal separator through the chain case and the valve cover

Also advantageous are embodiments of the internal combustion engine in which the crankcase and the at least one centrifugal separator are connected to each other by means of a riser, wherein the riser is at least partially disposed in the valve cover and / or the cylinder head and / or the cylinder block, so that the vent flow from the Crankcase is introduced through the riser in the at least one centrifugal separator.

A riser connection is particularly suitable if the internal combustion engine has no chain case, which could be used to connect the crankcase with the at least one centrifugal separator. The riser is also characterized by short flow paths, so that the vent flow does not need to travel too far to the at least one centrifugal separator, which also offers advantages, if only a small Overpressure in the crankcase to promote the contaminated with oil venting current is available or available.

Furthermore, the riser preferably has a rectilinear course, so that - if at all - only small amounts of oil are deposited on the way from the crankcase to the at least one centrifugal and also the connection between the crankcase and centrifugal only a small flow resistance for the venting flow, which ensures a vent even with a slight overpressure in the crankcase.

With regard to the two last-mentioned embodiments of the internal combustion engine according to the invention reference is also made at this point to the statements made above regarding the connection of the crankcase and centrifugal separator.

Embodiments of the internal combustion engine in which the at least one centrifugal separator is connected by means of a line to a vacuum source are advantageous in order to evacuate the gaseous constituents of the venting stream from the separating chamber.

Embodiments of the internal combustion engine in which the at least one centrifugal separator is connected by means of a line to the intake tract of the internal combustion engine are advantageous in order to evacuate the gaseous components of the venting stream from the deposition chamber. Even after passing through the separator, the venting stream is more or less contaminated with oil, so that it is advantageous from an ecological point of view to supply this gas stream to the combustion and burn it and not to conduct it into the environment.

Embodiments of the internal combustion engine in which the line opens downstream of a throttle flap arranged in the intake tract into the intake tract are advantageous. This embodiment of the internal combustion engine makes use of the fact that - especially in the partial load range - a pressure gradient across the more or less closed throttle valve, wherein behind the throttle valve. downstream of the throttle there is a negative pressure.

Advantageous embodiments of the internal combustion engine, in which in the line to the vacuum source, a valve is provided, with which the evacuation of the gaseous components from the deposition chamber is controlled. The valve serves - as already on outlined above - including the prevention of backflow from the intake into the at least one centrifugal separator, which not only makes evacuation difficult or impossible, but also increase the mass of air contaminated with oil, since the back flowing in the at least one centrifugal separator Air or the returning fuel-air mixture would mix with oil in the separator.

Embodiments of the internal combustion engine in which the at least one centrifugal separator is equipped with a separation chamber which tapers in the direction of a discharge opening for the liquid constituents are advantageous. This serves to reduce the radius of the trajectory of the oil droplets and thus the increase of the centrifugal forces acting on the oil droplets contained in the vent flow, whereby the deposition process is supported. The efficiency of the cleaning process and the degree of purity of the vent flow is thereby increased.

Embodiments of the internal combustion engine in which the at least one centrifugal separator is equipped with a calming chamber adjoining the separation chamber are advantageous.

Advantageous embodiments of the internal combustion engine, in which the at least one centrifugal separator is equipped with a second valve, with which the discharge of the liquid components is controlled. The valve is preferably located behind the settling chamber so that oil can be removed from the settling chamber by opening the valve.

Embodiments of the internal combustion engine in which a second connection of the crankcase to the at least one centrifugal separator is provided, which serves to return the separated liquid constituents to the crankcase, are advantageous.

Fig. 1

schematisch eine erste Ausführungsform im Querschnitt,

Fig. 2

schematisch die in Figur 1 dargestellte erste Ausführungsform im Längsschnitt,

Fig. 3a

schematisch eine zweite Ausführungsform - längs geschnitten - in der Draufsicht,

Fig. 3b

schematisch die in Figur 3a dargestellte zweite Ausführungsform entlang der in Figur 3a gekennzeichneten Schnittlinie A-A,

Fig. 4a

schematisch eine dritte Ausführungsform - längs geschnitten - in der Draufsicht, und

Fig. 4b

schematisch die in Figur 4a dargestellte dritte Ausführungsform entlang der in Figur 4a gekennzeichneten Schnittlinie B - B.

In the following the invention will be described in more detail with reference to three exemplary embodiments. Hereby shows:

Fig. 1

schematically a first embodiment in cross section,

Fig. 2

1 shows a longitudinal section through the first embodiment shown in FIG. 1,

Fig. 3a

schematically a second embodiment - cut longitudinally - in plan view,

Fig. 3b

2 schematically shows the second embodiment shown in FIG. 3a along the section line AA marked in FIG. 3a,

Fig. 4a

schematically a third embodiment - longitudinally cut - in plan view, and

Fig. 4b

schematically the third embodiment shown in Figure 4a along the marked in Figure 4a section line B - B.

Figure 1 shows schematically a section of a first embodiment of the internal combustion engine according to the invention in cross section.

The internal combustion engine has a valve cover 3, a cylinder head 4 and a cylinder block 5. The valve cover 3 serves to cover the camshaft and the valve trains (not shown) and has the task to seal these groups of components oil-tight against the environment and to protect against contamination. The valve cover 3 is connected to the cylinder head 4, wherein a separating plane 17 is formed between the valve cover 3 and the cylinder head 4. Similarly, the cylinder head 4 is connected to form a further parting plane 18 with the cylinder block 5.

In the embodiment shown in Figure 1, the already existing components, namely the valve cover 3, the cylinder head 4 and the cylinder block 5 are used in an advantageous manner to integrate two centrifugal 1 a, 1 b in the internal combustion engine. In this case, all the walls or functional surfaces of the centrifugal separators 1a, 1b are formed by the already existing components of the internal combustion engine.

Each centrifugal separator 1a, 1b is provided with a separation chamber 8a, 8b into which a vent stream coming from the crankcase and contaminated with oil is passed to separate the liquid components 15a, 51b, in particular the oil, and the gaseous components 16a, 16b to separate the vent flow. To form the connection between the crankcase and centrifugal separator 1a, 1b, the crankcase is connected, for example via a chain case (not shown) and the valve cover 3 with the deposition chambers 8a, 8b. In Figure 1 is a section this connection in the form of a first, arranged in the valve cover 3 connecting line 2a, 2b and a feed channel 2a, 2b visible.

The already realized in the valve cover 3 technical features, in particular the oil seal, are used to conduct the vent flow as free of leakage from the crankcase to centrifugal 1a, 1b, without the valve cover 3 would have to be structurally changed in view of this additionally assigned task.

In addition, the bleed stream can be used to lubricate the camshaft timing gear, camshaft and valve trains.

The contaminated with oil venting stream, which flows as a result of a pressure gradient from the crankcase to the centrifugal separator 1a, 1b, the precipitation chambers 8a, 8b via the feed channels 2a, 2b fed tangentially. This forms a circular cyclone flow d. H. a tangential flow 11a, 11b circulating in the separation chambers 8a, 8b, so that the liquid constituents 16a, 16b, in particular the oil, contained in the vent flow are deposited on the walls of the separation chambers 8a, 8b due to the centrifugal force.

The venting stream is then separated into its two phases, namely, on the one hand, the liquid phase 16a, 16b and, on the other hand, the gaseous phase 15a, 15b. Both phases can be removed separately from the deposition chambers 8a, 8b. In this case, the gaseous components 15a, 15b or the purified air streams 16a, 16b evacuated via vacuum lines 12a, 12b up from the deposition chambers 8a, 8b, whereas the deposited liquid components 16a, 16b taking advantage of the gravitational acceleration down from the Separating chambers 8a, 8b are discharged.

Each separation chamber 8a, 8b tapers in the direction of the discharge opening 19a, 19b, wherein the tapered portion 9a, 9b of the chambers 8a, 8b - as shown in Figure 1 - preferably has the shape of a truncated cone, so that the radius of the rotating tangential flow 11 a, 11 b when entering the conical section 9a, 9b steadily reduced, whereby the centrifugal forces acting on the oil droplets still in the exhaust flow, are increased, which further increases the efficiency of cleaning by additional deposits of oil.

Following the conical sections 9a, 9b, the oil flow 15a, 15b passes via the discharge openings 19a, 19b into settling chambers 10a, 10b, where the oil is collected. There is a second connection of the crankcase with the centrifugal separator 1a, 1b and the settling chamber 10a, 10b provided, which serves as a discharge channel 13a, 13b for discharging and returning the separated liquid components 15a, 15b in the crankcase.

With a arranged in the discharge line 13 a, 13 b valve 14 a, 14 b, the discharge or return operation can be controlled.

In order to simplify the integration of centrifugal separators 1a, 1b in the internal combustion engine, in particular to realize this integration cost, the parting plane 17 between the valve cover 3 and cylinder head 4 on the one hand and the parting plane 18 between the cylinder head 4 and cylinder block 5 on the other hand with regard to the training of Functional surfaces of centrifugal separators 1a, 1b used in an advantageous manner.

Thus, the first parting plane 17 is specifically arranged where the conical section 9a, 9b of the deposition chamber 8a, 8b merges into the cylindrical section, which is preferable from casting technical points of view, since otherwise undercuts would be to be feared with complex Gußkernstrukturen. The second parting plane 18 is provided where the calming chambers 10a, 10b end and pass into the discharge channels. This ensures that the calming chambers 10a, 10b are easily accessible at a position of their largest diameter, which in turn offers advantages of casting technology.

Figure 2 shows schematically the first embodiment shown in Figure 1 in longitudinal section.
In addition to Figure 1, the discharge of the purified air stream 16a is shown here. For this purpose, the separation chamber 8a is connected by means of a vacuum line 12a to a vacuum source, preferably to the intake tract of the internal combustion engine. Otherwise, reference is made to FIG. 1. The same reference numerals have been used for the same components.

Figure 3a shows schematically and in plan view a second embodiment in the longitudinal direction cut. The contaminated with oil vent flow flows through the chain case 7 and arranged in the valve cover 3 feed channel 2a from the crankcase to the centrifugal separator 1a. In this case, the vent flow of the deposition chamber 8a is supplied tangentially, so that in the deposition chamber 8a a revolving tangential flow 11a is formed. On the sides of the feed channel 2a on the one hand, the plunger 21 of the valve trains and on the other hand, the intake manifold 22 are arranged.

FIG. 3b schematically shows the second embodiment shown in FIG. 3a along the section line A-A marked in FIG. 3a.

The contaminated with oil vent flow passes through the feed channel 2a in the deposition chamber 8a. In the deposition chamber 8a, a circumferential tangential flow 11a is formed, wherein the liquid components contained in the vent flow 15a, in particular the oil, are deposited as a result of the centrifugal forces, so that two phases, namely on the one hand, the liquid phase or the oil and on the other hand, the gaseous phase available.

The gaseous constituents 16a are removed as purified air stream 16a via a vacuum line 12a upwards out of the separation chamber 8a. The separated liquid components 15a are discharged by utilizing the acceleration of gravity down from the deposition chamber 8a. In this case, the deposition chamber 8a initially tapers in the direction of the discharge opening 19a and forms a conical section 9a, as a result of which the centrifugal forces which act on the oil droplets still present in the deaeration stream are increased.

The oil flow 15a passes through the discharge ports 19a from the deposition chamber 8a into the settling chamber 10a, where the oil is collected. By means of a discharge channel 13a, in which a second valve 14a is arranged, the separated liquid components 15a are discharged into the crankcase.

In the embodiment illustrated in FIGS. 3 a and 3 b, the centrifugal separator 1 a is integrated into the valve cover 3 and the cylinder head 4. In contrast to the previously described embodiment, the cylinder block is not used for integration.

In order to simplify the integration of the centrifugal separator 1a, the parting plane 17 between the valve cover 3 and the cylinder head 4 is used to facilitate the formation of the functional surfaces of the centrifugal separator 1a in an advantageous manner that is provided at a suitable location. In addition, the valve cover 3 is modular, ie in the present case in two parts, wherein the valve cover 3 has a lower valve cover 3 'and an upper valve cover 3 ", which also supports the formation of the separation device.

Thus, the first parting plane 17 in the structure of the centrifugal separator 1a is specifically arranged at the upper end of the settling chamber 10a, which is preferable from casting technical points of view. This ensures that the settling chamber 10a is easily accessible at a location of its largest diameter. The Abscheidekammer 8 a with its conical portion 9 a is disposed completely in the valve cover 3 and can be produced in a simple manner, since the valve cover 3 is formed in two parts and the Abscheidekammer 8 a in the open state of the valve cover 3 i. in the disassembled state, the valve cover 3 is accessible.

The parting planes 17, 18 are provided with O-rings 23, so that a sufficient sealing function is ensured both in the parting plane 17 between the valve cover 3 and cylinder head 4 and in the parting plane 18 between the cylinder head 4 and cylinder block.

Figure 4a shows schematically and in plan view a third embodiment which is cut along the longitudinal direction. FIG. 4b shows this third embodiment along the section line B - B marked in FIG. 4a.

In contrast to the embodiment shown in Figures 3a and 3b, this third embodiment has a riser 20 to connect the crankcase and the at least one centrifugal separator 1a together. Only the differences from the embodiment shown in FIGS. 3a and 3b will be discussed, for which reason reference is made to FIGS. 3a and 3b. The same reference numerals have been used for the same components.

The riser 20 is partially integrated in the valve cover 3 and the cylinder head 4 and leads through the cylinder block to the crankcase (not shown). The vent flow can be passed in this way through the riser 20 into the centrifugal separator 1a. The bleed stream flowing through the riser 20 is fed tangentially to the centrifugal separator. The deposition or the separation of the liquid from the gaseous phase then takes place as already described in detail above.

The riser 20 is characterized by short flow paths and provides only a low flow resistance for the vent flow, so that a vent is ensured even if only a slight overpressure in the crankcase to promote the contaminated with oil vent flow is available.

reference numeral

1a

cyclone

1b

cyclone

2a

first connection line, supply channel

2 B

first connection line, supply channel

3

valve cover

3 '

lower valve cover

3 '

upper valve cover

4

cylinder head

5

cylinder block

6

Valve

7

chain case

8a

deposition

8b

deposition

9a

conical section of the deposition chamber

9b

conical section of the deposition chamber

10a

settling chamber

10b

settling chamber

11a

tangential

11b

tangential

12a

Vacuum line

12b

Vacuum line

13a

second connecting line, discharge channel

13b

second connecting line, discharge channel

14a

Valve

14b

Valve

15a

liquid components, oil flow

15b

liquid components, oil flow

16a

gaseous components, flow of purified air

16b

gaseous components, flow of purified air

17

Parting plane between the valve cover and cylinder head

18

Parting plane between cylinder head and cylinder block

19a

discharge opening

19b

discharge opening

20

riser

21

tappet

22

intake manifold

23

O-ring

Claims (24)

Method for ventilating a crankcase of an internal combustion engine, which has a cylinder block (5), a cylinder head (4) and at least one cover, for example a valve cover (3), in which the crankcase is equipped with at least one centrifugal separator (1a, 1b), so that a vent flow contaminated with oil is conducted from the crankcase to the at least one centrifugal separator (1a, 1b) due to a pressure gradient, and the vent flow of a separation chamber (8a, 8b) of the at least one centrifugal separator (1a, 1b). to form a circular circulating flow - is supplied tangentially, so that the liquid components contained in the vent flow (15a, 15b), in particular the oil, are deposited due to centrifugal force, and these deposited liquid components (15a, 15b) then of the gaseous components (16a, 16b) of the deaeration stream ge be separated, on the one hand the separated liquid components (15a, 15b) are discharged by utilizing the acceleration of gravity from the deposition chamber (8a, 8b) and on the other hand, the gaseous components (16a, 16b) from the deposition chamber (8a, 8b) are evacuated. Method according to claim 1,
characterized in that
the at least one centrifugal separator (1a, 1b) at least partially in the valve cover (3) and / or the cylinder head (4) and / or the cylinder block (5) is integrated, wherein the crankcase and the at least one centrifugal separator (1a, 1b) via a chain case (7) and the valve cover (3) are interconnected so that the bleed stream from the crankcase via the chain case (7) and the valve cover (3) in the at least one centrifugal separator (1a, 1b) is passed. Method according to claim 1,
characterized in that
the at least one centrifugal separator (1a, 1b) at least partially in the valve cover (3) and / or the cylinder head (4) and / or the cylinder block (5) is integrated, wherein the crankcase and the at least one centrifugal separator (1a, 1b) via a riser (20), which is at least partially formed in the valve cover (3) and / or the cylinder head (4) and / or the cylinder block (5), are interconnected, so that the vent flow from the crankcase via the riser (20 ) is passed into the at least one centrifugal separator (1a, 1b). Method according to one of the preceding claims,
characterized in that
the at least one centrifugal separator (1a, 1b) is connected by means of a line (12a, 12b) to a vacuum source in order to evacuate the gaseous components (16a, 16b) of the venting stream from the separation chamber (8a, 8b). Method according to claim 4,
characterized in that
the at least one centrifugal separator (1a, 1b) is connected by means of a line (12a, 12b) to an intake tract of the internal combustion engine to evacuate the gaseous components (16a, 16b) of the venting stream from the separation chamber (8a, 8b) (12a, 12b) is preferably connected to the intake tract downstream of a throttle valve arranged in the intake tract. Method according to claim 4 or 5,
characterized in that
in the line (12a, 12b) to the vacuum source, a first valve (6) is provided, with which the evacuation of the gaseous components (16a, 16b) from the deposition chamber (8a, 8b) is controlled. Method according to claim 6,
characterized in that
the valve (6) is opened when the pressure in the separation chamber (8a, 8b) is higher than the pressure of the negative pressure source, and the valve (6) is closed when the pressure in the separation chamber (8a, 8b) is lower than the pressure of the vacuum source. Method according to one of the preceding claims,
characterized in that
a centrifugal separator (1a, 1b) is used, whose deposition chamber (8a, 8b) tapers in the direction of a discharge opening (19a, 19b) for the liquid components (15a, 15b). Method according to one of the preceding claims,
characterized in that
a centrifugal separator (1a, 1b) is used which has a settling chamber (10a, 10b) adjoining the separation chamber (8a, 8b). Method according to one of the preceding claims,
characterized in that
the at least one centrifugal separator (1a, 1b) is equipped with a second valve (14a, 14b) with which the discharge of the liquid components (15a, 15b) is controlled. Method according to claim 10,
characterized in that
the second valve (14a, 14b) is opened when the pressure in the separation chamber (8a, 8b) is higher than the pressure in the crankcase, and the second valve (14a, 14b) is closed when the pressure in the separation chamber (8a , 8b) is lower than the pressure in the crankcase. Method according to one of the preceding claims,
characterized in that
the liquid components (15a, 15b) deposited in the at least one centrifugal separator (1a, 1b) are returned to the crankcase. Internal combustion engine for carrying out a method according to one of the preceding claims, which has a crankcase, a cylinder block (5), a cylinder head (4), at least one cover, for example a valve cover (3), an engine mount, and an intake tract as components,
characterized in that
at least one with a separation chamber (8a, 8b) equipped centrifugal separator (1a, 1b) is provided which is integrated in such a way in the internal combustion engine, that all walls of the at least one centrifugal separator (1a, 1b) are formed by components of the internal combustion engine a first connection (2a, 2b) of the crankcase with the at least one centrifugal separator (1a, 1b) is provided, through which a bleeding stream coming from the crankcase and contaminated with oil is directed into the at least one centrifugal separator (1a, 1b) liquid components (15a, 15b) to separate and separated from the gaseous components (16a, 16b) of the venting stream. Internal combustion engine according to claim 13,
characterized in that
the at least one centrifugal separator (1a, 1b) is at least partially integrated in the valve cover (3) and / or the cylinder head (4) and / or the cylinder block (5). Internal combustion engine according to claim 14,
characterized in that
the crankcase and the at least one centrifugal separator (1a, 1b) by means of a chain box (7) and a valve cover (3) are interconnected, so that the vent flow from the crankcase through the chain case (7) and the valve cover (3) in the at least a centrifugal separator (1a, 1b) can be introduced. Internal combustion engine according to claim 14,
characterized in that
the crankcase and the at least one centrifugal separator (1a, 1b) are interconnected by means of a riser (20), wherein the riser (20) at least partially in the valve cover (3) and / or the cylinder head (4) and / or the cylinder block ( 5) is arranged, so that the vent flow from the crankcase through the riser (20) in the at least one centrifugal separator (1a, 1b) can be introduced. Internal combustion engine according to one of claims 13 to 16,
characterized in that
the at least one centrifugal separator (1a, 1b) is connected by means of a line (12a, 12b) to a vacuum source in order to evacuate the gaseous components (16a, 16b) of the venting stream from the separation chamber (8a, 8b). Internal combustion engine according to claim 17,
characterized in that
the at least one centrifugal separator (1a, 1b) is connected by means of a line (12a, 12b) to the intake tract of the internal combustion engine in order to evacuate the gaseous constituents (16a, 16b) of the venting stream from the separation chamber (8a, 8b). Internal combustion engine according to claim 18,
characterized in that
the line (12a, 12b) opens into the intake tract downstream of a throttle valve arranged in the intake tract. Internal combustion engine according to one of claims 17 to 19,
characterized in that
in the line (12a, 12b) to the vacuum source, a valve (6) is provided, with which the evacuation of the gaseous components (16a, 16b) from the deposition chamber (8a, 8b) is controlled. Internal combustion engine according to one of claims 13 to 20,
characterized in that
the at least one centrifugal separator (1a, 1b) is equipped with a separating chamber (8a, 8b) which tapers in the direction of a discharge opening (19a, 19b) for the liquid components (15a, 15b). Internal combustion engine according to one of claims 13 to 21,
characterized in that
the at least one centrifugal separator (1a, 1b) is equipped with a settling chamber (10a, 10b) adjoining the separation chamber (8a, 8b). Internal combustion engine according to one of claims 13 to 22,
characterized in that
the at least one centrifugal separator (1a, 1b) is equipped with a second valve (14a, 14b) with which the discharge of the liquid components (15a, 15b) is controlled. Internal combustion engine according to one of claims 13 to 23,
characterized in that
a second connection (13a, 13b) of the crankcase with the at least one centrifugal separator (1a, 1b) is provided, which serves for the return of the separated liquid components (15a, 15b) in the crankcase.

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