DE102015200707A1 - A method for reducing the tendency to knock of a spark-ignited supercharged internal combustion engine and apparatus for carrying out the method - Google Patents

Abstract

The subject of the application relates to a method for reducing the tendency to knock of a spark-ignited supercharged internal combustion engine (1) with a low-pressure exhaust gas recirculation device (11) comprising at least the steps: a) condensing at least a portion of the exhaust gas recirculating device (11) flows through, contained gaseous water; b) buffering of the resulting condensate in a buffer (15) and c) feeding the condensate from the buffer (15) into a fresh gas tract (2) or injecting the condensate into a combustion chamber (23) of the internal combustion engine (1), and a device for Perform the procedure.

Description

The invention relates to a method for reducing the tendency to knock of a spark-ignited supercharged internal combustion engine and to an apparatus for carrying out the method.

Third-party, supercharged internal combustion engines are usually limited to a high load or full load operating state because of the highly compressed intake air in terms of knock limit. This phenomenon is usually met with a shift of the ignition timing in the direction of "late", but this means a loss of efficiency of the engine. Furthermore, the compression ratio is reduced to increase the knock limit in spark-ignited, supercharged engines, which also causes a loss of efficiency.

From the DE 10 2006 054 227 A1 is a method for reducing the emission of pollutants of an internal combustion engine and a device known for this purpose, in which condensate of a charge air cooler and condensate of an evaporator of an air conditioner is supplied to a storage container. This condensate is mixed by means of a metering pump in a fuel injection pump with the fuel, so that an emulsion is formed, which is supplied to the combustion chamber of a diesel engine.

From the DE 10 2010 048 466 A1 As the closest prior art, an exhaust gas recirculation (EGR) device is known, which is formed as a low-pressure exhaust gas recirculation device and having an exhaust gas recirculation cooler, wherein a condensate discharge device is provided for the discharge of condensate from the exhaust gas recirculation path. It is proposed to supply the resulting condensate by means of a condensate return line back to the exhaust stream or dissipate it into the environment.

From the US 2011/0168128 A1 It is known to withdraw water from a main exhaust gas stream and to supply it to a storage device. It is proposed to use the resulting water for knock suppression.

From the EP 2 161 438 A2 An internal combustion engine with a high-pressure exhaust gas recirculation device has become known in which condensate is separated off from a branched off exhaust gas of the high-pressure part of the exhaust system. This condensate is at least partially introduced via a discharge line in the low pressure part of the exhaust system, wherein additionally or alternatively, the condensate can be introduced by means of a metering unit in at least one feed air inlet passage of a combustion cylinder.

The object of the invention is to provide a method for reducing the tendency to knock of a spark-ignited, supercharged internal combustion engine and an apparatus for performing the method, with which an operation of the internal combustion engine with higher efficiency is possible. In particular, the method should make it possible to reduce the tendency to knock of the internal combustion engine, so that a stronger pre-ignition of the spark-ignition engine is made possible. In particular, an optimized MB50 time should be achieved.

This object is achieved by a method having the features of claim 1 and a device having the features of claim 11. Advantageous embodiments are given in the subclaims 2 to 10 and 12 to 17.

• a) Kondensieren zumindest eines Teils von im Abgas, welches die Niederdruck-Abgasrückführungseinrichtung durchströmt, enthaltenem gasförmigem Wasser;
• b) Zwischenspeichern des entstandenen Kondensates in einem Zwischenspeicher und
• c) Zuführen des Kondensats aus dem Zwischenspeicher in einen Frischgastrakt oder Einspritzen des Kondensats in einen Brennraum des Verbrennungsmotors.

According to the invention, it has been recognized that in a spark-ignited, supercharged internal combustion engine having a low-pressure exhaust gas recirculation device, the object can be achieved by carrying out at least the following steps:

• a) condensing at least a portion of gaseous water contained in the exhaust gas, which flows through the low-pressure exhaust gas recirculation device;
• b) buffering of the resulting condensate in a buffer and
• c) feeding the condensate from the buffer into a fresh gas tract or injecting the condensate into a combustion chamber of the internal combustion engine.

The invention makes use of the fact that in a spark-ignited, supercharged internal combustion engine, in particular a gasoline engine, the provision of a low-pressure exhaust gas recirculation device and condensing a flowing in the low-pressure exhaust gas recirculation device amount of exhaust gas can provide a significant amount of condensate available during the engine in a partial load range is operated. This is because the exhaust gas carries a high proportion of gaseous water in itself. The core idea of the invention is to extract the condensate from the exhaust gas flowing through the low-pressure exhaust gas recirculation device and to store it in a separate intermediate store. The condensate stored in the buffer is fed to a fresh gas tract of the internal combustion engine or injected directly into a combustion chamber of the engine, by means of direct water injection. By such a condensate injection or condensate injection, the knock limit can be shifted towards a more efficient engine operation. If the amount of injected water is increased, this can lead to an improvement, in particular to an advancement of the so-called MB50 time contribute. The MB50 point in time indicates the time at which 50% of the fuel located in the combustion chamber are converted by combustion thereof. This MB50 timing is ideally 6 ° to 8 ° after top dead center (TDC) of a piston of the internal combustion engine. Without the method according to the invention, as described above, for example, an ignition point must be shifted so far "late" to avoid knocking that the MB50 point is no longer within the ideal window of 6 ° to 8 ° after top dead center (TDC) ), but would also be undesirably moved towards "late". The term MB50 time is an abbreviation for the English term "mass fraction burns 50", which indicates the time at which 50% of the mass of the fuel gas or the fuel gas-air mixture are chemically converted.

In a preferred embodiment, the feeding of the condensate into the fresh gas tract or the injection of the condensate into the combustion chamber of the internal combustion engine in an operating state of the internal combustion engine, in which the exhaust gas recirculation is inactive or throttled, which is effected in particular in a high part-load or full load operating condition. Thus, in this embodiment, the exhaust gas recirculation device is preferably activated in a low or medium part-load range and condensate is extracted from the exhaust gas in these operating states. In these operating states, however, no injection or supply of the condensate takes place in the combustion chamber or in the fresh gas tract. The resulting condensate is temporarily stored in the buffer and provided for subsequent operation of the internal combustion engine in high part load or full load operating condition. In high partial load or full load operating state exhaust gas recirculation according to the invention is inactive or throttled, so that no further condensate is obtained or condensate is obtained only to a reduced extent.

A supercharged, spark-ignited internal combustion engine usually has a charge air cooling of the compressed by a supercharger fresh air or the compressed fresh gas. In the way of this intercooler charge air condensate may be incurred, especially if the intake fresh air is particularly humid, that is, has a particularly large amount of gaseous water. During intercooling, which takes place over the entire operating range, that is, from the idle state to the full load operating state of the internal combustion engine, charge air condensate constantly accumulates, for example, in an intercooler, which charge is advantageously likewise supplied to the intermediate store. This has the advantage that the buffer is also supplied with condensate, if the exhaust gas recirculation is inactive and thus always contains enough condensate to provide sufficient condensate even for very long-lasting high part-load or full load operating conditions of the internal combustion engine.

In a further preferred embodiment, the condensate is the Frischgastrakt in the flow direction of the fresh gas to a charge air cooler, in particular fed to a throttle valve, or injected by direct injection directly into the combustion chamber of the engine. In this case, the condensate can be supplied via Kondensatinjektoreinrichtungen the Frischgastrakt or the combustion chamber, the Kondensatinjektoreinrichtungen are additional injectors to the fuel injectors. In a modification, the condensate can also be mixed in particular by a common injector for fuel and condensate, and a fuel / condensate mixture can be supplied to the fresh gas tract or injected into the combustion chamber by means of the fuel injector.

In an advantageous embodiment, the condensate is supplied from the intermediate storage of a condensate injector, this being done in particular with a conveyor, in particular feed pump or a metering pump.

Conveniently, the exhaust gas, which is provided for Druchströmung the low-pressure Abgasrückführungseirichtung and thus for the extraction of condensate, in the flow direction of a Hauptabgasstranges after a drive means of an exhaust gas driven supercharger, for. B. a turbocharger diverted from the main exhaust stream. This has the advantage that the entire mass flow of exhaust gas of the main exhaust gas flow is available for driving the exhaust-driven supercharger.

In particular, it makes sense that the exhaust gas, which is provided for the flow through the low-pressure exhaust gas recirculation device, in the flow direction of the main exhaust line after an exhaust gas purification device z. As a catalyst or a particulate filter, is branched off.

In a particular embodiment of the invention, the feeding of the condensate into the fresh gas tract or the injection of the condensate into the combustion chamber takes place in an operating state of the internal combustion engine which is more than 75% of the full load operating state, in particular more than 85% of the full load operating state. In such operating conditions of the internal combustion engine (more than 75%, in particular more than 85% of the full load operating state), the exhaust gas recirculation within the low-pressure exhaust gas recirculation device is inactive or at least throttled in a particularly preferred manner, so that in these Operating conditions no or less condensate is obtained from the exhaust gas recirculation device.

In order to be able to permanently store a sufficient amount of condensate in the intermediate store, at least one further condensate from a different condensate source than the low-pressure exhaust gas recirculation device is advantageously fed to the intermediate store. Such another condensate source may be, for example, the condenser of the air conditioner or a charge air cooler or other condensate-forming devices of a motor vehicle. It is also conceivable to keep a certain amount of water available in a separate tank, which can be supplied to the buffer if there is the danger that over-long operation of the internal combustion engine at full load or high part-load range may result in a lack of condensate in the buffer ,

A device according to the invention has to solve the problem of the invention a spark-ignited, supercharged internal combustion engine with a low-pressure exhaust gas recirculation device, wherein the low-pressure exhaust gas recirculation device at least one capacitor, for. B. a charge air cooler, the z. B. a Kondensatabscheidereinrichtung has for condensing at least a portion of the exhaust gas, which flows through the low-pressure exhaust gas recirculation means contained gaseous water and has a buffer for receiving the resulting condensate, which is fluidly connected to the capacitor. The device is further formed by having a condensate supply device for feeding the condensate into a fresh gas tract or for directly injecting the condensate into a combustion chamber of the internal combustion engine.

With such a device, the inventive method can be carried out while achieving the desired advantages.

In a preferred embodiment, there is a charge air cooler, which is fluidically connected to the intermediate storage, so that charge air condensate accumulating in the way of charge air cooling can be fed to the intermediate storage.

The condensate supply device preferably has at least one metering device, with which in the flow direction of Frischgastraktes after a charge air cooler, in particular after a throttle and in front of a combustion chamber of the internal combustion engine, the condensate from the buffer to the fresh gas is metered or the condensate can be injected directly into a combustion chamber of the engine. This makes it possible to equip a supercharged, spark-ignition internal combustion engine with a direct or indirect water injection.

Furthermore, suitably a conveyor, z. B. a metering pump or delivery pump, by means of which the condensate from the buffer of the water supply is supplied.

Preferably, a branch point of the low-pressure exhaust gas recirculation device in the flow direction of an exhaust gas in a main exhaust line of a drive device of an exhaust gas driven supercharger and / or a catalyst and / or a particulate filter arranged downstream.

In a preferred manner, one or more further, resulting in the operation of a motor vehicle condensates, the intermediate memory can be supplied.

It is useful that a control device is provided, by means of which the Kondensatzuführeinrichtung in response to operating parameters of the internal combustion engine and / or a position of an exhaust gas recirculation valve is operable, wherein the Kondensatzuführeinrichtung is activated when the exhaust gas recirculation valve is in a throttle position or closed.

Further advantageous embodiments are given in the following description of the drawing.

The invention will be explained in more detail by way of example with reference to the drawing. The only 1 schematically shows a device according to the invention, with which the inventive method is feasible.

A device according to the invention for carrying out the method according to the invention has an internal combustion engine 1 with a fresh gas tract on the inlet side 2 and a main exhaust line on the exhaust side 3 on. In the fresh gas tract 2 fresh gas flows in a first flow direction 4 , In the main exhaust line 3 exhaust gas flows in a second flow direction 5 , In the main exhaust line 3 is from the combustion engine 1 seen from downstream, first a drive device 6 an exhaust-driven supercharger 7 , in particular a turbocharger arranged. The drive device 6 the loader 7 is mechanically with a charger 8th for compressing fresh gas in connection. The loader device 8th is as a compressor, the drive device 6 preferably as a turbine.

Further downstream is in the main exhaust line 3 an exhaust gas purification device 9 , such as a catalyst and / or a particulate filter arranged. Further downstream in the second flow direction 5 the exhaust gas purification device 9 downstream, is a branch point 10 present, at least part of the main exhaust line 3 flowing exhaust gas of a low pressure exhaust gas recirculation device 11 (hereinafter referred to as ND-AGR) can be fed. The LP-EGR 11 forms a Nebenabgasstrang. Downstream behind the junction 10 is the remaining exhaust further components (not shown) of an exhaust system fed. These other components may be silencers, for example. The LP-EGR 11 points in a third flow direction 12 one after the other at least one capacitor 13 , z. Example, an exhaust gas cooler, by means of which the exhaust gas flowing through the LP EGR is cooled and contained in this exhaust gas constituents can be converted into a liquid state, that is, condensable, can be converted into condensate. A component of the exhaust gas to be condensed is in particular gaseous water, which is contained in the exhaust gas and is converted by condensation into liquid water. The way in the exhaust gas cooler 13 resulting condensate is via a first condensate line 14 a cache 15 for temporary storage of condensate can be supplied.

In the direction of the third flow direction 12 is the exhaust gas cooler 13 an exhaust gas recirculation valve 16 downstream, by means of which an exhaust gas flow through the LP EGR 11 is releasable, throttable and / or lockable. In the direction of the third flow direction 12 seen, the ND-AGR flows 11 at a confluence point 17 in the fresh gas tract 2 so that the exhaust, which is the ND-EGR 11 flows through, the fresh gas can be supplied. In the fresh gas tract 2 sits, from the estuary 17 seen upstream, against the first flow direction 4 of fresh gas an air filter 18 for cleaning sucked fresh air. In the flow direction 4 from the confluence point 17 downstream, ie the mouth point 17 downstream, passes the fresh gas, which optionally with exhaust gas from the LP EGR 11 is offset, in the charging device 8th the loader 7 and is condensed. After the charging device 8th is in the fresh gas tract 2 a charge air cooler 19 arranged, with the compressed fresh gas is coolable. In this case, under certain operating conditions, a second condensate accumulates, which flows via a second condensate line 20 the cache 15 can be fed. This second condensate is largely water and is called in the following charge air condensate. The intercooler 19 in the flow direction 4 downstream sits a throttle valve device 21 by means of the fresh gas volume flow in the fresh gas tract 2 is releasable and / or throttled.

After the throttle valve device 21 the fresh gas passes through inlet channels 22 in combustion chambers 23 of the internal combustion engine 1 ,

From the cache 15 out there is cached condensate 24 which at least contains condensate, which from the exhaust gas cooler 13 comes, cached.

Via a third condensate line 25 is the condensate 24 from the cache 15 by means of a conveyor 26 for the condensate 24 , In particular a feed pump or a metering pump Kondensatzufüinrichtunginrichtung 27 fed. The condensate feed device 27 has injectors 28 , by means of which condensate is metered and, in particular, can be supplied as a function of operating parameters of the internal combustion engine. The supply takes place via a control device 29 controlled and / or regulated in the inlet channels 22 or directly into the combustion chambers 23 , In such a Kondensatzuführeinrichtung is a so-called water injection device, in which the water is added to the fresh gas before the combustion chambers. Of course, it is alternatively also possible, the condensate feed 27 to train as directly injecting water injection, in which the injectors 28 directly into the combustion chambers 23 of the internal combustion engine 1 lead and thus the injector supplied condensate 23 directly, that is without the interposition of inlet channels 22 into which combustion chambers can be injected.

As long as the ND-AGR 11 Exhaust gas flows through, falls in the exhaust gas cooler 13 Condensate on which the buffer 15 is supplied.

In idle, low part-load and middle part-load torque of the internal combustion engine 1 is the exhaust gas recirculation valve 16 at least partially open, so that a partial exhaust stream, the LP-EGR 11 flows through and the mass flow of fresh gas to the confluence 17 elevated. It has proven to be advantageous that a supply or injection of condensate by means of the condensate supply device 27 in the combustion chambers 23 or in the inlet channels 22 then takes place when the internal combustion engine 1 is in an operating state in the range of high partial load or full load. In such operating states, the exhaust gas recirculation valve is preferred 16 in a throttle position or in a closed position, so that only a reduced or no amount of exhaust gas through the LP EGR 11 flows. Thus arises in this operating condition on the exhaust gas cooler 13 no condensate. To an inadmissible, low level of condensate 24 in the cache 15 To avoid, it is advantageous a second condensate from a second condensate source, such as the intercooler 19 the cache 15 supply. This has the advantage that in the Intercooling independent of the load condition of the internal combustion engine over the entire load range charge air condensate is formed, and this is particularly in the high part load or full load operation of the internal combustion engine accumulates in large quantities. The boundary between the medium part-load and the high part-load range is between 75% and 85% of the full load operation of the internal combustion engine. Within this range, a switching point can be selected, in which the exhaust gas recirculation valve 16 closes and the supply of condensate by means of Kondensatzuführeinrichtung 27 starts. Such a switching point can be determined by test bench runs of an individual internal combustion engine or of an individual combustion engine type with the adjacent units.

Alternatively, it is also possible, in particular within the limits of 75% to 85% of full load operation with a load increase, the exhaust gas flow through the LP EGR 11 continuously or gradually reduced until no more exhaust gas through the LP EGR 11 flows. Load balanced or synchronous to close the exhaust gas recirculation valve 16 may the condensate feeding device 27 with increasing load continuously higher amounts of water (condensate quantities) inject, so that an overlap area, in which both exhaust still by the ND-EGR 11 flows as well as a supply of condensate to the fresh gas or takes place in the combustion chamber. However, it is preferred that the water injection / condensate injection takes place when the LP EGR 11 is inactive. This means that initially in a transition region between the middle part load and the high part load, the exhaust gas flow through the LP EGR 11 is reduced and reduced to zero to a predetermined operating point, that is, the EGR valve 16 is closed. Only after the EGR valve 16 is completely closed, begins with further increasing engine load, the condensate feed, for example by means of the water injection device. The increase of the injected amount of water with increasing load can be carried out continuously or stepwise, at full load preferably a maximum amount of water per cycle of the internal combustion engine 1 injected or supplied.

In the method according to the invention deliberately becomes an LP-EGR 11 to form condensate from the ND-EGR 11 guided exhaust selected. As ND-AGR 11 According to the invention, an exhaust gas recirculation device is to be understood, in which the branching point 10 at least after a drive device 6 a loader 7 is arranged so that at the branch point 10 after flowing through the drive device 6 already a partially relaxed and partially cooled exhaust gas, compared with the exhaust gas in the state before entering the drive device 6 of the loader, is present. This makes it possible by means of a lower cooling, that is, a lower heat removal of the exhaust gas cooler 13 flowing exhaust gas, already to obtain condensate in sufficient quantity. Would exhaust by way of high pressure exhaust gas recirculation, ie in the flow direction 5 seen before the drive device 6 be diverted so the exhaust gas for the high-pressure exhaust gas recirculation device is much hotter and must be cooled much more strong until reaching a dew point of a component in the exhaust gas, so that there is a higher cooling demand. Furthermore, the inventive method has the advantage that by providing a LP-EGR 11 the entire exhaust gas volume flow to drive the drive device 6 is available because before the drive device 6 no exhaust gas flow is diverted.

Furthermore, it is advantageous in the device according to the invention and in the method according to the invention that further condensate sources are used in the operation of a motor vehicle, with which it can be ensured that even during long-term operation of the internal combustion engine 1 in high part-load or full-load operation, during which the LP EGR 11 is inactive or at least throttled, always enough condensate 24 in the cache 15 In stock is enough condensate for the condensate supply device even at langartigen such operating conditions 27 is available. Thus, the beginning of the condensate injection and the amount of injected condensate with increasing load depending on the operating state of the exhaust gas recirculation valve 16 can be determined, for example, is a signal line 30 present, which is a current position of the exhaust gas recirculation valve 16 the control device 29 provides.

LIST OF REFERENCE NUMBERS

1

 internal combustion engine

2

 Fresh gas tract

3

 Main exhaust line

4

 1st flow direction

5

 2nd flow direction

6

 driving means

7

 loaders

8th

 Charging device

9

 exhaust gas cleaning device

10

 branching point

11

 Low pressure exhaust gas recirculation (ND-EGR)

12

 3rd flow direction

13

 capacitor

14

 1. condensate line

15

 cache

16

 Exhaust gas recirculation valve

17

 opening point

18

 air filter

19

 Intercooler

20

 2nd condensate line

21

 throttle device

22

 intake ports

23

 combustion chambers

24

 condensate

25

 3. condensate line

26

 Conveyor

27

 Kondensatzuführeinrichtung

28

 injectors

29

 control device

30

 signal line

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 102006054227 A1 [0003]
• DE 102010048466 A1 [0004]
• US 2011/0168128 A1 [0005]
• EP 2161438 A2 [0006]

Claims (17)

Method for reducing the tendency to knock of a spark-ignited, supercharged internal combustion engine ( 1 ) with a low-pressure exhaust gas recirculation device ( 11 ) comprising at least the steps of: a) condensing at least a portion of the exhaust gas that contains the low-pressure exhaust gas recirculation device ( 11 ) flows through, contained gaseous water; b) temporarily storing the resulting condensate in a buffer ( 15 ) and c) feeding the condensate from the buffer ( 15 ) into a fresh gas tract ( 2 ) or injecting the condensate into a combustion chamber ( 23 ) of the internal combustion engine ( 1 ). A method according to claim 1, characterized in that the feeding of the condensate into the fresh gas tract ( 2 ) or the injection of the condensate into the combustion chamber ( 23 ) of the internal combustion engine ( 1 ) in an operating state of the internal combustion engine ( 1 ), in which the exhaust gas recirculation is inactive or throttled, in particular in a high part-load or full-load operating state. A method according to claim 1 or 2, characterized in that a charge air cooling accumulating charge air condensate the buffer ( 15 ) is supplied. Method according to one of the preceding claims, characterized in that the condensate the fresh gas tract ( 2 ) in the flow direction of a fresh gas after a charge air cooler ( 19 ), in particular after a throttle valve ( 21 ) or directly into the combustion chamber ( 23 ) of the internal combustion engine ( 1 ) is injected. Method according to one of the preceding claims, characterized in that condensate from the buffer ( 15 ), by means of a conveyor ( 26 ) or a metering pump of a condensate feed device ( 27 ) is supplied. Method according to one of the preceding claims, characterized in that the exhaust gas, which flows through the low-pressure exhaust gas recirculation device ( 11 ), in the flow direction of a main exhaust line ( 3 ) after a drive device ( 6 ) of an exhaust-driven supercharger ( 7 ) is diverted from the main exhaust stream. Method according to one of the preceding claims, characterized in that exhaust gas, which flows through the low-pressure exhaust gas recirculation device ( 11 ), in the flow direction of the main exhaust line ( 3 ) after an exhaust gas purification device ( 9 ) is diverted. Method according to one of the preceding claims, characterized in that the feeding of the condensate into the fresh gas tract ( 2 ) or the injection of the condensate into the combustion chamber ( 23 ) in an operating state of the internal combustion engine ( 1 ), which is more than 75% of the full load operating state, in particular more than 85% of the full load operating state, takes place. Method according to one of the preceding claims, characterized in that the buffer ( 15 ) at least one further condensate from a different condensate source than the low-pressure exhaust gas recirculation device ( 11 ) is supplied, which also occurs when the low-pressure exhaust gas recirculation is inactive or throttled. Method according to one of the preceding claims, characterized in that the exhaust gas recirculation in an operating state above 75%, in particular above 85% of the full load operating state of the internal combustion engine ( 1 ) is inactive or throttled. Device for carrying out the method according to one of claims 1 to 10, comprising a spark-ignited, supercharged combustion engine ( 1 ) with a low-pressure exhaust gas recirculation device ( 11 ), wherein the low-pressure exhaust gas recirculation device ( 11 ) at least one capacitor ( 13 ) for condensing at least a portion of gaseous water contained in the exhaust gas, which flows through the low-pressure exhaust gas recirculation device, and a buffer ( 15 ) for receiving the resulting condensate, which fluidly with the capacitor ( 13 ), characterized in that the device comprises a condensate feed device ( 27 ) for feeding the condensate into a fresh gas tract ( 2 ) or for injecting the condensate in a combustion chamber ( 23 ) of the internal combustion engine ( 1 ) owns. Apparatus according to claim 11, characterized in that a charge air cooler ( 19 ), which fluidly with the buffer ( 15 ) is connected, so that in the way of a charge air cooling accumulating charge air condensate the buffer ( 15 ) can be fed. Device according to one of claims 11 or 12, characterized in that the Kondensatzuführeinrichtung ( 27 ) at least one injector ( 28 ), with which in the flow direction of the fresh gas tract ( 2 ) after the intercooler ( 19 ), in particular after a throttle valve ( 21 ) and in front of a combustion chamber ( 23 ) of Internal combustion engine ( 1 ) the condensate from the buffer ( 15 ) can be added to the fresh gas or the condensate directly into a combustion chamber ( 23 ) of the internal combustion engine ( 1 ) is injectable. Device according to one of claims 11 to 13, characterized in that a conveyor ( 26 ) is present, by means of the condensate from the buffer ( 15 ) of the condensate feed device ( 27 ) can be fed. Device according to one of claims 11 to 14, characterized in that a branch point ( 10 ) of the low-pressure exhaust gas recirculation device ( 11 ) in the flow direction of an exhaust gas in a main exhaust line ( 3 ) a drive device ( 6 ) of an exhaust-driven supercharger ( 7 ) and / or an exhaust gas purification device ( 9 ) is subordinate. Device according to one of claims 11 to 15, characterized in that further, resulting in the operation of a motor vehicle condensates the buffer ( 15 ) can be supplied. Device according to one of claims 11 to 16, characterized in that a control device ( 29 ) is present, by means of the Kondensatzuführeinrichtung ( 27 ) as a function of operating parameters of the internal combustion engine ( 1 ) and / or a position of an exhaust gas recirculation valve ( 16 ) is operable, the Kondensatzuführeinrichtung ( 27 ) is activated when the exhaust gas recirculation valve ( 16 ) is in a throttle position or is closed.

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