EP2010761A1

EP2010761A1 - Deaerating and aerating device for a supercharged internal combustion engine

Info

Publication number: EP2010761A1
Application number: EP07728280A
Authority: EP
Inventors: Mirko Braun; Robert Dunsch; Stefan Ruppel; Yakup ÖZKAYA
Original assignee: Mahle International GmbH
Current assignee: Mahle International GmbH
Priority date: 2006-04-25
Filing date: 2007-04-19
Publication date: 2009-01-07
Anticipated expiration: 2027-04-19
Also published as: CN101449032B; CN101449032A; JP2009534584A; US20100000499A1; US8191538B2; DE502007006370D1; DE102006019636A1; WO2007122172A1; EP2010761B1

Abstract

The present invention relates to a deaerating and aerating device (19) for an internal combustion engine (1) for discharging blowby gas out of a crankcase (3), comprising a first line (20) which is connected at one end to the crankcase (3) and at the other end to a fresh gas line (7) downstream of a supercharging device (10) and which contains a deaerating valve (23), and a second line (21) which is connected at one end to the fresh gas line (7) upstream of the supercharging device (10) and at the other end to the crankcase (3) and which contains a throttle device (28) and, parallel thereto, a non-return check valve (29) which provides a blocking action in the direction of the crankcase (3).

Description

Deaeration and ventilation device for a supercharged internal combustion engine

The present invention relates to a degassing and Beluftungs- device for a supercharged internal combustion engine, especially in a motor vehicle, for discharging blow-by gas from a Kurbeigehause the internal combustion engine.

In internal combustion engines, which are designed as a piston engine, during operation so-called blow-by gases from combustion chambers of the internal combustion engine enter a crankcase of the internal combustion engine. The amount of blowby gases produced depends on the operating condition of the internal combustion engine, e.g. Apprenticeship or full load, from. In order to avoid an inadmissibly high overpressure in the Kurbeigehause, the Blowbygase must be removed from the Kurbeigehause. In this case, an emission of blow-by gases into the environment for environmental reasons is undesirable.

Accordingly, a venting device usually comprises a line which is connected at one end to the Kurbeigehause and the other end is connected to a fresh gas line of the internal combustion engine. Blowbyga- se are again supplied to the internal combustion engine for combustion. In order to exclude the emission of blow-by gases into the environment, it is expedient to suck the blow-by gases out of the crankcase in such a way that a negative pressure is established in the crankcase. Such a negative pressure is regularly available in the fresh air line at least in naturally aspirated engines, in particular after a throttle valve. However, under certain operating conditions in the fresh gas line, negative pressures can arise which are so great that they can lead to destruction of the crankcase. With the help of vacuum control valves while trying to adjust the negative pressure in the crankcase to a predetermined value.

In supercharged internal combustion engines, additional problems arise in that an introduction of the blow-by gases upstream of the respective charging device is undesirable per se in order to avoid contamination thereof. However, only a sufficient negative pressure is available on the pressure side of the charging device when the internal combustion engine is operating in idling mode or in a lower part-load operation.

A venting device preferably comprises a first line, which is connected at one end to the crankcase and the other end downstream of the charging device to the fresh gas line. The first line contains a vent valve, usually a vacuum control valve, which is designed so that it is from a predetermined limit of a adjacent thereto differential pressure limits a volume flow leading to the fresh gas line to a predetermined target value. A venting and aeration device may usually additionally have a second line which is connected at one end upstream of the charging device to the fresh gas line and at the other end also to the crankcase. This second line includes a throttle device which is designed such that it adjusts a volume flow leading to the crankcase to a predetermined target value at a predetermined value of a differential pressure applied thereto.

In idle operation of the internal combustion engine prevails at the junction between the first line and fresh gas line, especially if this is downstream of a throttle valve, a relatively strong negative pressure, whereby relatively much blowby gas can be removed from the crankcase. However, only comparatively little blowby gas is produced during idling operation. The second line allows ventilation of the crankcase for this case of operation by supplying fresh air sucked in upstream of the charging device to the crankcase in order to avoid an inadmissibly large negative pressure in the crankcase.

As the part load increases, the negative pressure at the connection point of the first line drops, while at the same time the amount of blow-by gas to be removed in the crankcase increases. Accordingly, the amount of fresh air supplied via the second pipe decreases. From a certain partial load of the enough at the connection point of the first line prevailing negative pressure is no longer in the Kurbeigehause set the desired negative pressure. In this case, the negative pressure at the junction of the first line is smaller than the negative pressure at the junction of the second line. As a result, the direction of flow in the second line is reversed so that it now ensures the ventilation of the Kurbeigehauses. The first line may expediently be equipped with a back-up blocking device, whereby the first line is automatically blocked in the direction of the spa after the pressure in the fresh-gas line at the connection point of the first line continues to increase.

With further increasing partial load or at full load prevails downstream of the charging device overpressure in the fresh gas line. The first line is then blocked and the discharge of blowby gases takes place exclusively via the second line.

In certain operating states of the internal combustion engine, in particular at full load, the negative pressure prevailing at the upstream of the charging device in the fresh gas line is comparatively small, so that adequate suction of the blowby gases is not always guaranteed. In particular, when the connection point of the second line, eg for reasons of space, must be positioned relatively close to the inlet of the charging device, the problem is exacerbated. The present invention is concerned with the problem of providing for a venting device of the type mentioned an improved embodiment, which is particularly characterized in that it allows a sufficient venting even with a relatively small negative pressure, thereby providing comparatively flexible connection options on the side of the fresh gas line offers.

This problem is solved according to the invention by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea to arrange in the second line parallel to the throttle device, a non-return valve that locks to the crankcase out. This ensures that when venting the crankcase through the second line, the blow-by gases do not have to flow through the throttle device, but can flow through the non-return valve that opens in this direction. The flow resistance can be reduced in this flow direction, which already sufficient relatively small negative pressures sufficient to be able to aspirate Blowbygas. As a result, the second line can also be connected to those points of the fresh gas line, where only a comparatively small negative pressure can be provided, which improves the mounting flexibility of the deaerating and ventilating device. Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

It is understood that the features mentioned above and those yet to be explained below can be used not only in the particular combination given, but also in other combinations or in isolation, without departing from the scope of the present invention.

Preferred embodiments of the invention are illustrated in the drawings and will be explained in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components.

Show, in each case schematically,

1 to 3 each show a greatly simplified schematic diagram of a dehumidifying device with different operating states.

1 to 3, an internal combustion engine 1 comprises an engine block 2 with Kurbeigehause 3, cylinder head 4, cylinder head cover 5 and oil pan 6. A fresh gas line 7 leads fresh gas from an environment 8 to the engine block 2, while an exhaust pipe 9 exhaust gas of the internal combustion engine 1 from Engine block 2 dissipates and emitted into the environment 8. The internal combustion engine 1 is preferably arranged in a motor vehicle. The internal combustion engine 1 is charged and accordingly has a charging device 10, which in the present case is configured by way of example as an exhaust gas turbocharger. Accordingly, the charging device 10 comprises a compressor 11, which is arranged in the fresh gas line 7, and a turbine 12, which is arranged in the exhaust pipe 9. It is clear that the internal combustion engine 1 can also be equipped with another charging device 10, such as a mechanical supercharger, in particular a Roots blower.

The fresh gas line 7 contains on the input side an air filter 13 and downstream thereof an air mass or air mass measuring device 14, which is configured for example as a hot film knife. Downstream of the charging device 10, the fresh gas line 7 includes a charge air cooler 15 and downstream of a throttle valve 16th

Furthermore, the internal combustion engine 1 is equipped with an exhaust gas recirculation device 17, which is reproduced here in a simplified manner and represented only by an exhaust gas recirculation cooler 18.

In addition, the internal combustion engine 1 is equipped with a venting and venting device 19, with the help of which in the operation of the internal combustion engine 1 Blowbygas can be removed from the crankcase 3. Such Blowbygas occurs during operation of the internal combustion engine 1 due to leaks Unspecified cylinder chambers of the engine block 2 in the crankcase 3 a.

The deaerating and ventilating device 19 comprises a first line 20 and a second line 21. The first line 20 is connected at one end to the crankcase 3 and at the other end to the fresh gas line 7 via a first connection point 22. The first connection point 22 is located downstream of the charging device 10 and in particular downstream of the throttle valve 16. At the same time, the first connection point 22 is positioned within the fresh gas line 7 upstream of an unspecified inlet point of the exhaust gas recirculation device 17. The first line 20 includes a vent valve 23, which may be configured as a kind of vacuum control valve. The vent valve 23 is designed so that it limits a leading to the fresh gas line 7 volume flow to a predetermined target value from a predetermined limit of a voltage applied thereto differential pressure.

In the examples shown here, a non-return device 24 is also arranged in the first conduit 20, which blocks in the direction of the crankcase 3 and is effective in series with the vent valve 23. Preferably, the non-return device 24 is integrated in the vent valve 23, whereby a uniform assembly 25 is formed, which is formed by a vent valve with integrated non-return function. The second line 21 is at one end at a second junction 26, which is located upstream of the charger 10, connected to the fresh gas line 7, while the other end also and preferably independent of the first line 20, in particular directly, is connected to the crankcase 3.

The second line 21 contains a throttle device 28, which is designed such that it sets a leading to the first line 20 volume flow to a predetermined target value for a predetermined value of a pressure applied thereto differential pressure. In addition, the second line 21 is equipped with a return check valve 29, which blocks in the direction of the first line 20. Here, return check valve 29 and throttle device 28 are arranged in parallel durchstromsbar, whereby the throttle device 28 forms a return check valve 29 bypassing, which is also referred to below with 28. Preferably, the return check valve 29 and the throttle device 28 may also form an integral component 30. This component 30 is formed in particular by the return check valve 29 with integrated bypass 28.

The first line 20 contains a first separation device 31, which is designed to remove oil and / or oil mist from the blow-out gas sucked out of the spa casing 3 during operation of the internal combustion engine 1. The separated oil can via a first return line 32 from the first separator 31 in the Kurbeigehause 3, preferably into the oil pan 6, be brought back. In the preferred embodiment shown here, the second line 21 also contains its own second separation device 27 with associated second oil supply line 36.

The inventive Entluftungseinrichtung 19 operates as follows:

In a reproduced in Fig. 1 first operating state, the internal combustion engine 1 operates in an idle mode, ie in an operating state with a minimum load. In this operating condition comparatively little blow-by gas enters the spa 3. At the same time, the charging device 10 is substantially inactive; at least causes the throttle valve 16 is a strong throttling, whereby downstream of the throttle valve 16 in the fresh gas line 7, a comparatively large negative pressure prevails. This negative pressure is so great that it is above the limit value of the Entluftungsventils 23 and above the predetermined value of the throttle device 28. Accordingly, the bleed valve 23 passes the predetermined volume flow. The first line 20 causes a venting of the Kurbeigehauses 3. In this case, 20 more gas can be removed in this operating state via the first line as nachstromt new blowby.

At the same time, a negative pressure established at the second connection point 26 in the fresh gas line 7 is smaller than the negative pressure prevailing at the first connection point 22. The vent through the first line 20 lowers in Crankcase 3 the pressure as far as until the pressure equalization fresh gas can flow on the second line 21. As a result, the throttle device 28 also allows a volume flow, which, however, is smaller than the predetermined volume flow of the vent valve 23. The second line 21 causes ventilation of the crankcase 3 with fresh gas from the fresh gas line 7.

The vent valve 23 and the throttle device 28 are specifically coordinated so that flows in this case with minimal deducted from the crankcase 3 Blowbygasmenge in the crankcase 3 just enough fresh gas via the second line 21, that can set a predetermined negative pressure in the crankcase 3 , In particular, the negative pressure in the crankcase 3 should not fall arbitrarily far in this operating state. Accordingly, in this operating state, the volume flow drawn off via the first line 20 from the crankcase 3 and discharged into the fresh gas line 7 is in part formed by the amount of blowby gas to be removed and otherwise by a corresponding amount of fresh gas which is supplied to the crankcase 3 via the second line 21.

With increasing load of the internal combustion engine 1, the amount of blowby gases accumulating in the crankcase 3 also increases, so that correspondingly more blow-by gas has to be removed. Due to the throttle effect of the throttle device 28, the volume flow of the fresh gas supplied to the crankcase 3 simultaneously decreases in a corresponding manner. The Blowbygasströmung is symbolized in Fig. 1 by arrows 33. The fresh gas flow is symbolized in FIG. 1 by arrows 34 and the mixture flow composed of blow-by gas and fresh gas is symbolized in FIG. 1 by arrows 35.

Fig. 2 shows an operating condition of the internal combustion engine 1 at partial load, in which at the first connection point 22 in the fresh gas line 7, only a comparatively small negative pressure is present, which is just so large that the total amount of blowby gas still on the first line 20 from the crankcase 3 can be dissipated and introduced into the fresh gas line 7. For this purpose, in a special way, a vent valve 23, which is characterized by a characteristic in which increases with increasing pressure difference of the vent valve 23 by flow rate first (linear), then at a mean differential pressure has a maximum for the flow and at further increasing pressure difference falls to the predetermined, with further increasing pressure difference constant target value (linear). Advantageously, said maximum is in the range of a pressure difference, which rests in the reproduced in Fig. 2 operating state of the internal combustion engine 1 at the vent valve 23. In this operating state, the amount of fresh gas added to the blow-by gas via the second line 21 is very small and may even decrease to zero. To clarify the flow arrows for the Frischgasstromung 34 shown with broken lines.

Since the fresh gas stream 34 is virtually negligible in this operating state, in the first line 20 there is virtually only the blow-by gas stream 33 present.

With further increasing load, especially at full load, the state shown in Fig. 3 is established. On the one hand, the negative pressure established at the first connection point 22 becomes too small in order to be able to extract the amount of blowby gas produced. On the other hand, at the first connection point 22, in particular by the connection or activation of the charging device 10 in conjunction with a corresponding throttle position, build up an overpressure that makes it impossible to initiate Blowbygas via the first connection point 22 in the fresh gas line 7. The jerk lock device 24 locks in the event of overpressure at the first connection point 22.

With increasing pressure on the pressure side of the charging device 10, the pressure on the suction side of the charging device 10 decreases. As a result, at the second connection point 26, a negative pressure is created, which is sufficient to suck off the blow-by gases accumulating in the spa casing 3 only through the second line 21. The second line 21 causes in this case the desired venting of the Kurbeigehauses 3. This is in principle possible via the throttle device 28, which is indicated here by dashed lines shown flow arrows is. However, in this flow direction, the return check valve 29 opens, so that the Blowbygasstromung 33, at least the main part, flows through the return check valve 29.

Preferably, the return check valve 29 is designed such that its opening resistance and through-flow resistance are smaller than the flow resistance of the bypass or throttle device 28. In particular, the opening resistance and the throughflow resistance of the non-return valve 29 are selected so that the opening at the second connection point 26 prevailing negative pressure is sufficient to suck the resulting in this operating state or state range Blowbygasmenge from the Kurbeigehause 3. In this way, a predetermined negative pressure can be set in the Kurbeigehause 3. The second line 21 is quenched in the opening direction of the non-return valve 29 due to the very small resistances for opening and flow through the return check valve 29, so that even with comparatively small underpressures sufficient ventilation can be achieved, whereby it is particularly possible, the second connection point 26 to be positioned relatively close to an inlet of the charging device 10.

Claims

claims

1. Ent- and ventilation device for a supercharged internal combustion engine (1), in particular in a motor vehicle, for discharging blowby gas from a crankcase (3) of the internal combustion engine (1),

- With a first line (20) at one end to the crankcase (3) connected or connectable, the other ends downstream of a charging device (10) of the internal combustion engine (1) to a fresh gas line (7) of the internal combustion engine (1) is connected or connectable and which contains a venting valve (23) which is designed such that it limits a volume flow leading to the fresh gas line (7) to a predetermined target value from a predetermined limit value of a differential pressure applied thereto,

- With a second line (21) which is connected at one end upstream of the charging device (10) to the fresh gas line (7) or connectable, the other end to the crankcase (3) is connected or connectable and which contains a throttle device (28) is configured so that they at a predetermined value of an applied differential pressure to the crankcase

(3) sets the leading flow rate to a predetermined target value, - Wherein the second line (21) parallel to the throttle device (28) from the fresh gas line (7) to the crankcase (3) blocking return check valve (29), so that the throttle device (28) a return check valve (29) bypassing (28 ).

2. Deaeration and deaeration device according to claim 1, characterized in that the bypass (28) or the throttle device (28) in the return check valve (29) is integrated.

3. Deaeration and deaeration device according to claim 1 or 2, characterized in that an opening resistance and a through-flow resistance of the return check valve (29) are smaller than a through-flow resistance of the bypass (28) or the throttle device (28).

4. Deaeration and deaeration device according to one of claims 1 to 3, characterized in that an opening resistance and a through-flow resistance of the return check valve (29) are selected so that in a full load operation of the internal combustion engine (1) at a connection point (26) which the second line (21) to the fresh gas line (7) is connected, prevailing negative pressure sufficient in the Kurbeigehause (3) to set a predetermined negative pressure or to suck a predetermined amount of Blowbygas-.

5. Deaeration and ventilation device according to one of claims 1 to 4, characterized in that the first line (20) includes a non-return device (24) which blocks from the fresh gas line (7) to the connection point (27).

6. venting and ventilating device according to claim 5, characterized in that the non-return device (24) in the vent valve (23) is integrated.

7. Ent- and ventilation device according to one of claims 1 to 6, characterized in that the vent valve (23) and the bypass (28) or the throttle device (28) are coordinated so that in an idling operation of the internal combustion engine (1) of Pressure drop in the crankcase (3) is limited to a predetermined negative pressure or the Blowbygas suction from the crankcase (3) is limited to a predetermined volume flow.

8. deaerating and ventilating device according to one of claims 1 to 7, characterized - That the first line (20) downstream of a charge air cooler

(15) is connected to the fresh gas line (7), and / or

- That the first line (20) downstream of a throttle valve

(16) is connected to the fresh gas line (7), and / or

- That the first line (20) is connected upstream of a discharge point of a Abgasruckfuhreinrichtung (17) to the fresh gas line (7).

9. Deaeration and deaeration device according to one of claims 1 to 8, characterized

- That the second line (21) downstream of an air mass meter (14) to the fresh gas line (7) is connected, and / or

- That the second line (21) downstream of an air filter

(13) is connected to the fresh gas line (7).

10. Deaeration and deaeration device according to one of claims 1 to 9, characterized in that in the first line (20) and in the second line (21) each have a separating device (27, 31) for removing oil and / or oil mist the blowby gas is arranged.

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