DE102014215364B4 - Internal combustion engine - Google Patents

Abstract

An internal combustion engine having an internal combustion engine (10), a fresh gas train and an electrically driven compressor (26) integrated in the fresh gas train, wherein the electrically driven compressor (26) is integrated into a bypass (28) bypassing a fresh gas line section (30) characterized in that a control element
in a first, the Frischgasstrangabschnitt (30) between an orifice (34) of the bypass (28) and a branch (32) of the bypass (28) closing position is movable,
in a second, the Frischgasstrangabschnitt (30) at least partially releasing position is movable and
in a third, the Frischgasstrang downstream of the mouth (34) of the bypass (28) or upstream of the junction (32) of the bypass (28) closing position is movable, wherein a closure element closes the bypass (28) in the second position of the control element and releases in the first position of the control element.

Description

The invention relates to an internal combustion engine with an internal combustion engine, a fresh gas train and an integrated in the fresh gas train, electrically driven compressor, wherein the electrically driven compressor is integrated into a fresh gas bypass section bypass.

From the EP 1 995 427 A1 is a corresponding, charged by means of an exhaust gas turbocharger internal combustion engine with intercooler known in which in addition to the compressor of the exhaust gas turbocharger still an electrically driven compressor is integrated into the fresh gas train. The electrically driven compressor is arranged there either upstream or downstream of the compressor of the exhaust gas turbocharger. In the embodiment with an arrangement downstream of the compressor of the exhaust gas turbocharger, the electrically driven compressor is integrated in a bypass of the fresh gas line. About a arranged at the downstream mouth of the bypass switching element, the fresh gas flow is guided either via the bypass and thus the electrically driven compressor or via a direct connection between the compressor of the exhaust gas turbocharger and the charge air cooler. As a result, it can be avoided that the electrically driven compressor, which should only be used for a short time to support the exhaust gas turbocharger, must be flowed through by the fresh gas when not in use.

By the switching element, the fresh gas flow is guided either via the bypass and thus the electrically driven compressor or bypassing the electrically driven compressor; However, a complete interruption of the fresh gas supply by closing the fresh gas line is thus not possible. Such closing of the fresh gas train is often provided in particular in diesel engines to avoid hunting after the diesel engine after shutdown. For this purpose, a separate flap in the fresh gas line is then regularly provided.

Also from the DE 101 64 792 B4 an internal combustion engine is known, which has a charge by means of an exhaust gas turbocharger and a supplementary electrically driven compressor, which is arranged upstream of the exhaust gas turbocharger. Again, a fresh gas line section bypassing the electrically driven compressor is provided, via which the fresh gas is guided when the electrically driven compressor is not in operation in order to avoid flow losses when flowing through the non-active, electrically driven compressor. The guidance of the fresh gas is controlled via either the electrically driven compressor or the bypassing fresh gas line section by means of a valve integrated into the fresh gas section. A similar internal combustion engine, which differs in that the electrically driven compressor is arranged downstream of the exhaust gas turbocharger, shows the font DE 10 2012 009 288 A1 ,

Even with these internal combustion engines, a complete closure of the fresh gas section by means of the integrated valve is not possible, so that a separate closure flap would also be required here for a corresponding functionality.

The document DE 10 2013 021 654 A1 discloses an internal combustion engine with an electrically driven compressor disposed downstream of a compressor of an exhaust gas turbocharger. The electrically driven compressor is integrated in a bypass, in which additionally a first control element is arranged. After the branch of the bypass and in front of the mouth, a second control element is arranged in the fresh air line.

The publication US 2014/0 007 835 A1 describes an internal combustion engine with an exhaust gas turbocharger and a three-way throttle valve, which allows to optionally bypass a charge air cooler.

The document WO 00/28 203 A shows a two-valve valve of an internal combustion engine, in which both flaps are arranged one behind the other on coaxial shafts of an actuator. The valve is located upstream of the compressor of an exhaust gas turbocharger and controls the exhaust gas recirculation of the internal combustion engine. Also, US 2011/0 061 380 A1 discloses the control of the exhaust gas recirculation by means of a three-way valve, which is arranged upstream of a compressor of an exhaust gas turbocharger.

The document DE 10 2010 060 060 A1 discloses a three-way throttle valve of an internal combustion engine which is adapted to control or completely release the flow of fresh air in a fresh gas train and to direct the fresh air into a bypass of the fresh gas train.

Based on this prior art, the present invention seeks to provide a way to control a guide of fresh gas in the fresh gas line of an electrically driven compressor comprehensive internal combustion engine in a structurally simple way possible.

This object is achieved by an internal combustion engine according to claim 1. Advantageous embodiments thereof are subject matter of the further claims and will become apparent from the following description of the invention.

• - in eine erste, den Frischgasstrangabschnitt zwischen einer Mündung des Bypasses und einer Abzweigung des Bypasses (zumindest teilweise, vorzugsweise möglichst vollständig) verschließende Stellung bewegbar ist,
• - in eine zweite, den Frischgasstrangabschnitt (zumindest teilweise, vorzugsweise möglichst vollständig, zumindest jedoch mehr als in der ersten Stellung) freigebende Stellung bewegbar ist und
• - in eine dritte, den Frischgasstrang stromab der Mündung des Bypasses oder stromauf der Abzweigung des Bypasses (zumindest teilweise, vorzugsweise möglichst vollständig) verschließende Stellung bewegbar ist.

A generic internal combustion engine which comprises at least one internal combustion engine, a fresh gas train and an electrically driven compressor integrated in the fresh gas train, wherein the electrically driven compressor is integrated into a bypass of the fresh gas train bypassing a fresh gas train section is characterized according to the invention by a control element which

• in a first, the Frischgasstrangabschnitt between an orifice of the bypass and a branch of the bypass (at least partially, preferably as completely as possible) closing position is movable,
• - In a second, the Frischgasstrangabschnitt (at least partially, preferably as completely as possible, but at least more than in the first position) releasing position is movable and
• - In a third, the Frischgasstrang downstream of the mouth of the bypass or upstream of the junction of the bypass (at least partially, preferably as completely as possible) closing position is movable.

Furthermore, the internal combustion engine according to the invention comprises a closure element which closes the bypass (at least partially, preferably as completely) when the control element is in its second position, and the bypass (at least partially, preferably as completely as possible, but at least more than in the other position ) releases when the rule element is in its first position.

The control element of the internal combustion engine according to the invention thus comprises at least three positions, wherein in the first position, the fresh gas (primary) is passed through the electrically driven compressor by the Frischgasstrangabschnitt between the junction and the mouth of the bypass is closed. In this position, the control element is to be switched in particular when an operation of the electrically driven compressor is provided. This may be particularly the case temporarily in an operation of the internal combustion engine after a load step (i.e., after a significant increase in the load request), in particular from low speeds and low load out.

In the second position of the control element, the fresh gas (primary) is passed over the Frischgasstrangabschnitt because it is open and the fresh gas therefore already tends to flow because of the lower flow resistance through the Frischgasstrangabschnitt. This position of the control element is provided primarily in a non-operation of the electrically driven compressor. The fresh gas must then not flow through the deactivated electrically driven compressor, whereby flow losses can be kept low.

However, the control element does not close the bypass receiving the electrically driven compressor in the second position, so that, without the likewise provided closure element, it would still be flowed through by fresh gas in at least a small extent. This would not only be functionally unnecessary and associated with flow losses, but could also have a disadvantageous effect in particular with regard to a temperature load on the through or around flowed components of the electrically driven compressor. This is especially true since a switching of the control element in the second position may be preferably provided in particular during operation of the internal combustion engine at high loads and in particular at full load, which is associated with correspondingly high temperatures of the fresh gas.

This is especially true if, as provided in a preferred embodiment of the internal combustion engine according to the invention, the electrically driven compressor is preceded by another compressor, in particular mechanically driven (eg by the internal combustion engine itself or by a turbine integrated into an exhaust line of the internal combustion engine ( as part of an exhaust gas turbocharger)). This further compressor, which is preferably arranged upstream of the branch of the bypass, compresses the fresh gas, which is associated with a corresponding increase in temperature. The compression of the fresh gas and thus its temperature increase increases in principle with increasing load, in which the internal combustion engine is operated, and thus tends to be highest at full load.

A resulting from the compression of the fresh gas temperature increase can be at least partially reversed in a known manner by the integration of a charge air cooler in the fresh gas line. To have to use only a charge air cooler, which can cancel both caused by the further compressor and by the electrically driven compressor temperature increase may preferably be provided, the charge air cooler downstream of the electrically driven compressor and in particular downstream of the mouth of the electrically driven compressor receiving bypass into the fresh gas train to integrate. However, this results in that the electrically driven compressor with the not yet cooled fresh gas is applied.

However, such loading of the electrically driven compressor with a hot fresh gas flow is prevented in the second position of the control element, because then the bypass is closed by the closure element separately and thus a fresh gas flow is prevented by this.

This can advantageously make it possible to form the electrically driven compressor and in particular also those components which are flowed through by the fresh gas in the operation of the electrically driven compressor from relatively temperature-sensitive materials and in particular (partially) from plastics. This is especially true since the fresh gas in the operating conditions of the internal combustion engine, in which the electrically driven compressor is to be operated (load jump from low speeds and low load out) and therefore is flowed through by the fresh gas, because of the low compressor power of another compressor one only has relatively low temperature.

In the third position of the control element, a flow of the fresh gas through both the Frischgasstrangabschnitt and through the bypass is interrupted (preferably substantially completely). In this position, the control element can be switched in particular when an operation of the internal combustion engine is to be terminated or has already ended. A hunting of the internal combustion engine by unwanted supply of fresh gas to the engine can be avoided.

The risk of overrun of the internal combustion engine is given in particular in self-igniting internal combustion engines, so that an embodiment of the internal combustion engine according to the invention to a particular extent in combination with a self-igniting internal combustion engine (in particular diesel engine) is advantageous.

In addition to the three defined positions, the control element can also be switched to any other positions. This makes it possible to lead in a defined manner partial flows of the fresh gas over both the electrically driven compressor and the Frischgasstrangabschnitt and / or in principle to achieve a throttling of the internal combustion engine supplied fresh gas flow.

In a structurally particularly simple embodiment of the internal combustion engine according to the invention can be provided that the control element is designed as a control flap, which is arranged rotatably in the region of the mouth or the branch within the fresh gas line, wherein the control flap in the first position and in the second position with different Alignments is aligned obliquely with respect to the central longitudinal axes of the fresh gas section and the bypass. In this case, the control flap can be connected in particular with a rotatably mounted flap shaft.

In order to be able to adjust the at least three defined positions by means of such a control flap, it can furthermore be provided that a longitudinal relationship of the rotation axis of the flap shaft is aligned centrally with respect to the cross section of the portion of the fresh gas line receiving the control flap. In particular, the flap shaft may be guided diagonally or chord-like running through the section of the fresh gas line.

Furthermore, it can be provided to always couple the position of the closure element to the position of the control element. Such a coupling can be provided in particular mechanically. For this purpose, the closure element may be mechanically coupled to the control element such that switching the control element from the first position to the second position to switch the closure element into a closed position and switching the control element from the second position to the first position to switch the Closing element leads to an open position. This can lead to a structurally particularly simple embodiment of the internal combustion engine according to the invention, wherein in particular it can be provided that the closure element is rotatably connected to the control flap.

In a structurally particularly simple embodiment of the internal combustion engine according to the invention may also be provided that the closure element is designed as a closure flap, which is rotatably disposed within the bypass.

The indefinite articles ("a", "an", "an" and "an"), in particular in the patent claims and in the description generally describing the claims, are to be understood as such and not as number words. Corresponding to this concretized components are thus to be understood that they are present at least once and may be present more than once.

• 1: ein Strukturschaubild eines Ausführungsbeispiels einer erfindungsgemäßen Brennkraftmaschine;
• 2: einen Abschnitt des Frischgasstrangs der Brennkraftmaschine in einer perspektivischen Darstellung;
• 3: den Abschnitt des Frischgasstrangs gemäß der 2 in einer teilweisen geschnittenen Darstellung;
• 4: einen Querschnitt durch den eine Regelklappe umfassenden Abschnitt des Frischgasstrangs mit der Regelklappe in einer ersten Stellung;
• 5: eine Darstellung gemäß der 4 mit der Regelklappe in einer zweiten Stellung; und
• 6: eine Darstellung gemäß der 4 und 5 mit der Regelklappe in einer dritten Stellung.

The invention will be explained in more detail using an exemplary embodiment with reference to the drawings. In the drawings shows:

• 1 a structural diagram of an embodiment of an internal combustion engine according to the invention;
• 2 a section of the fresh gas line of the internal combustion engine in a perspective view;
• 3 : the section of the fresh gas train according to the 2 in a partial sectional view;
• 4 a cross section through the portion of the fresh gas line comprising a control flap with the control flap in a first position;
• 5 : a representation according to the 4 with the control flap in a second position; and
• 6 : a representation according to the 4 and 5 with the control flap in a third position.

That in the 1 illustrated embodiment of an internal combustion engine includes an internal combustion engine 10 , This is designed for example as a four-cylinder, operated by the diesel process reciprocating internal combustion engine. The internal combustion engine 10 Fresh gas is supplied via a fresh gas train into combustion chambers, which are fed by cylinders 12 are formed in connection with piston guided up and down, for the combustion of directly via injectors 14 injected fuel is used. The internal combustion engine comprises a high-pressure fuel supply system with a so-called common rail 16 over which all injectors 14 be supplied with high-pressure fuel. The resulting during combustion exhaust gas is removed via an exhaust line.

In the exhaust system is a turbine 18 an exhaust gas turbocharger integrated. An impeller of the turbine 18 is rotatably driven by the exhaust gas flow, this rotation via a shaft to an impeller of a compressor integrated in the fresh gas line 20 the exhaust gas turbocharger is transmitted. The rotation of the impeller of the compressor 20 causes a compression of the fresh gas and thus an increase in the mass flow of convertible into the combustion chambers fresh gas. This improves the filling of the combustion chambers and thus the achievable performance of the internal combustion engine 10 ,

In order to prevent part of the filling improvement realized by the compression from being compensated by the temperature increase of the fresh gas which accompanies the compression, there is a charge-air cooler 22 provided, which cools the compressed fresh gas. The intercooler 22 is in a suction tube 24 the fresh gas train integrated, whereby a compact design of the internal combustion engine and an effective cooling of the fresh gas can be realized.

The compression capacity of the exhaust gas turbocharger is dependent on the exhaust gas mass flow. This has a negative effect in particular if, in the short term, low load speeds and loads result in an increased load requirement (load jump) to the internal combustion engine 10 is provided. This increased load requirement must first be converted into an increased exhaust gas mass flow, which then can only lead to the desired compression of the fresh gas. In particular, the response of the internal combustion engine 10 to improve after such a load jump, the internal combustion engine has an electric driven compressor 26 on, the downstream of the compressor 20 the exhaust gas turbocharger is integrated into the fresh gas train.

The electrically driven compressor 26 is how out of the 2 and 3 results, in the immediate vicinity and very close to the one part of the intake manifold 24 forming intercooler 22 arranged. In addition, there is the electrically driven compressor 26 on the curvature inside of a pipe bend of the fresh gas line. The corresponding portion of the fresh gas train is thus arcuate about a portion of the circumference of the electrically driven compressor 26 led around.

The electrically driven compressor 26 is still in a bypass 28 to a section of the pipe bend representing Frischgasstrangabschnitt 30 integrated. The bypass 28 branches off from a first section of the pipe bend and opens into a second section of the pipe bend. It is both the turnoff 32 as well as the estuary 34 of the bypass 28 arranged on the curvature inside of the pipe bend.

In the area of the estuary 34 of the bypass 28 is in the fresh gas train a control valve 36 arranged. The control flap 36 includes two semi-oval flap parts 38 in coplanar alignment with a flap shaft 40 are attached (see. 4 to 6 , however, only one flap part as a result of the illustrated cross section 38 demonstrate). The flap shaft 40 is rotatable in diagonal orientation within the fresh gas line in the region of the mouth 34 of the bypass 28 arranged. By means of a (eg electrical or pneumatic) actuator 42 is the flap shaft 40 and thereby the entire control flap 36 within the Frischgasstrangs rotatably adjustable. At least three defined positions for the control flap 36 intended. A corresponding control of the actuator 42 is performed by a (not shown) engine control of the internal combustion engine.

One end of the valve shaft 40 extends into an end portion of the bypass 28 and is rotatable there with a flap 44 connected.

In a first position of the control flap 36 this closes the fresh gas line within the fresh gas section 30 upstream of the estuary 34 and downstream of the junction 32 of the bypass 28 (see. 1 . 3 and 4 ) as completely as possible. In this case, the flap level of the control flap 36 an oblique orientation with respect to both a central longitudinal axis 66 of the fresh gas section 30 as well as a central longitudinal axis 68 of the bypass 28 (each in the area of the control flap 36 ) (cf. 1 ). In the first position of the control flap 36 is essentially the entire fresh gas flow through the bypass 28 and thus over the electrically driven compressor 26 guided. This first position of the control flap 36 is during operation of the electrically driven compressor 26 intended.

To the flow of fresh gas through the bypass 28 If possible not to hinder, it is the rotationally fixed with the control flap 36 connected flap 44 in a position in which the flap plane is oriented substantially in the flow direction of the fresh gas and thus blocks the bypass only with the size of its flap cross-section. In this position gives the shutter 44 the bypass 28 as free as possible.

In a second position of the control flap 36 this gives the flow path through the fresh gas section 30 as free as possible. This is the control flap 36 in a position in which the flap plane of the two flap parts 38 are aligned substantially in the direction of the flow direction of the fresh gas (see. 5 ) or the central longitudinal axis 66 of the fresh gas section 30 runs approximately in or parallel to the valve plane.

When the control flap 36 in the second position, there is the shutter 44 in a position where they bypass 28 essentially completely closes. This is the flap level of the flap 44 transverse to the direction of the (suppressed) flow of the fresh gas (or to the central longitudinal axis 68 ) in the corresponding section of the bypass 28 aligned (cf. 5 ).

An arrangement of the butterfly valve 36 in the second position and, associated therewith, closing the bypass 28 through the flap 44 is particularly provided for operation of the internal combustion engine at high loads and in particular full load, since in this case the compressor 20 the exhaust gas turbocharger ensures sufficient compression power and a supplementary operation of the electrically driven compressor 26 is not needed. By closing the bypass 28 This prevents the fresh gas (partially) from passing through the bypass 28 flows, causing not only flow losses, in particular by flowing through an impeller of the electrically driven compressor 26 would be avoided, but also a loading of the electrically driven compressor 26 is prevented with the already highly compressed and thus a high temperature having fresh gas.

In a third position of the control flap 36 this closes the fresh gas line downstream of the mouth 34 of the bypass 28 as completely as possible (cf. 6 and dashed lines shown position of the control valve 36 in the 1 ). In this case, the flap level of the control flap 36 also an oblique orientation with respect to both the central longitudinal axis 66 of the fresh gas section 30 as well as the central longitudinal axis 68 of the bypass 28 (each in the area of the control flap 36 ), which is rotated relative to the oblique orientation in the first position by, for example, about 90 °. In the third position of the control flap 36 is the fresh gas supply to the internal combustion engine 10 largely interrupted. This position of the butterfly valve 36 is particularly provided when the internal combustion engine 10 not (further) to be operated and unwanted Nachverbrennungen should be prevented.

Because in this third position of the control flap 36 In principle, no relevant fresh gas flow is given by the Frischgasstrang, is the corresponding adjusting position of the flap 44 in principle irrelevant. In the present case arises for the shutter 44 due to the non-rotatable connection with the flap shaft 40 the control flap 36 one the bypass 28 partially closing and partially releasing position.

The exhaust system also includes an exhaust manifold 46 in which the individual cylinders 12 associated outlet channels are transferred into a common flow channel. Between the exhaust manifold 46 and the turbine 18 of the exhaust gas turbocharger branches off a high-pressure exhaust gas recirculation 48 from the exhaust line. This can be controlled via an exhaust gas recirculation valve 50 defines exhaust gas in the fresh gas line in the area of the intake manifold 24 be returned. Furthermore, downstream of the turbine 18 an exhaust aftertreatment device 52 intended. Between the turbine 18 and the exhaust aftertreatment device 52 still goes a low-pressure exhaust gas recirculation 54 from the exhaust line. By means of this, exhaust gas in the Frischgasstrang upstream of the compressor 20 be returned to the exhaust gas turbocharger. The low pressure exhaust gas recirculation 54 integrates a filter 56 and a cooler 58 for the return exhaust gas and another exhaust gas recirculation valve 60 ,

The fresh gas train still includes an upstream of the compressor 20 the exhaust gas turbocharger arranged air filter 62 for cleaning the fresh gas sucked in from the environment as well as between the air filter 62 and the compressor 20 the exhaust gas turbocharger arranged air mass meter 64 ,

LIST OF REFERENCE NUMBERS

10

internal combustion engine

12

cylinder

14

injector

16

Common rail

18

Turbine of the exhaust gas turbocharger

20

Compressor of the exhaust gas turbocharger

22

Intercooler

24

suction tube

26

electrically driven compressor

28

bypass

30

Fresh gas line section

32

Branch of the bypass

34

Mouth of the bypass

36

control flap

38

flap parts

40

flap shaft

42

actuator

44

flap

46

exhaust manifold

48

High-pressure exhaust gas recirculation

50

Exhaust gas recirculation valve of the high-pressure exhaust gas recirculation

52

exhaust treatment device

54

Low-pressure exhaust gas recirculation

56

Low pressure exhaust gas recirculation filter

58

Cooler of low pressure exhaust gas recirculation

60

Exhaust gas recirculation valve of the low-pressure exhaust gas recirculation

62

air filter

64

Air flow sensor

66

Center longitudinal axis of the fresh gas section

68

Center longitudinal axis of the bypass

Claims (10)

Internal combustion engine having an internal combustion engine (10), a fresh gas train and an electrically driven compressor (26) integrated in the fresh gas train, the electrically driven compressor (26) being integrated into a bypass (28) bypassing a fresh gas section (30), characterized in that a control element - in a first, the Frischgasstrangabschnitt (30) between an orifice (34) of the bypass (28) and a branch (32) of the bypass (28) closing position is movable - in a second, the Frischgasstrangabschnitt (30) at least partially releasing position is movable and - in a third, the Frischgasstrang downstream of the mouth (34) of the bypass (28) or upstream of the junction (32) of the bypass (28) closing position is movable, wherein a closure element the bypass (28) in the second position of the control element closes and releases in the first position of the control element. Internal combustion engine according to Claim 1 , characterized in that the control element as a control flap (36) is formed, which is arranged in the region of the mouth (34) or the branch (32) of the bypass (28) rotatably within the Frischgasstrangs, wherein the control flap (36) in the first Position and in the second position with different orientation obliquely with respect to the central longitudinal axes (66, 68) of the Frischgasstrangabschnitts (30) and the bypass (28) is aligned. Internal combustion engine according to Claim 2 , characterized in that the control flap (36) comprises a rotatably mounted flap shaft (40). Internal combustion engine according to Claim 3 , characterized in that a longitudinal axis of the flap shaft (40) is aligned centrally with respect to the cross section of the control flap (36) receiving portion of the fresh gas line. Internal combustion engine according to Claim 3 or 4 , characterized in that the flap shaft (40) is guided diagonally or chordally extending through the the control flap (36) receiving portion of the fresh gas line. Internal combustion engine according to one of the preceding claims, characterized in that the closure element is coupled to the control element such that a switching of the Control element from the first position to the second position to a switching of the closure element in a closed position and a switching of the control element from the second position to the first position leads to a switching of the closure element in an open position. Internal combustion engine according to one of Claims 2 to 5 and Claim 6 , characterized in that the closure element rotatably connected to the control flap (36). Internal combustion engine according to one of the preceding claims, characterized in that the closure element is designed as a closure flap (44) which is rotatably disposed within the bypass (28). Internal combustion engine according to one of the preceding claims, characterized by a further compressor (20) integrated in the fresh gas train upstream of the branch (32) of the bypass (28). Internal combustion engine according to one of the preceding claims, characterized by an intercooler (22) integrated downstream of the mouth (34) of the bypass (28).

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