EP3309381B1 - Exhaust gas recirculation cooler for an internal combustion engine - Google Patents

Description

The invention relates to an exhaust gas recirculation cooler for an internal combustion engine, in particular a motor vehicle according to the preamble of claim 1.

The exhaust gas is cooled in an exhaust gas recirculation cooler, which is subsequently fed to combustion chambers of an internal combustion engine again together with the combustion air. In particular, the exhaust gas recirculation coolers are used in motor vehicles with diesel engines in order to reduce exhaust gas emissions by returning the cooled exhaust gas to the combustion chambers.

To cool the exhaust gas, several cooling tubes are arranged in a row in a housing to form a tube bundle. The cooling tubes are mostly made of stainless steel winglet tubes, in which flow obstacles for better heat transfer are integrally formed - for example by stamping. The exhaust gas flows through the winglet tubes and is cooled by a coolant flowing in the housing. An exhaust gas inlet and an exhaust gas outlet are generally each provided by a diffuser, the respective diffuser being connected to the housing and forming an interface to the customer connection.

In order to achieve a better heat transfer between the exhaust gas and the coolant, a longer and uniform exposure to the coolant is aimed at the tube bundle. However, since the amount of coolant flowing in is limited, it is difficult to achieve a longer and even exposure of the tube bundle to the coolant. Different solutions for improving the heat transfer between exhaust gas and coolant are already known from the prior art. DE 196 54 366 A1 discloses, for example, cooling pipes with flow obstacles on the wall of the cooling pipe are attached. DE 10 2010 008 176 B4 and DE 11 2013 004 680 T5 disclose turbulence inserts that are arranged around the cooling tubes.
DE 199 61 284 A1 discloses a wire wall element that encases a tube and creates a turbulent flow around it. Also
DE 10 2009 038 643 A1 and DE 10 2007 005 370 A1 disclose cooling tubes with integral flow obstacles and inserts that can be arranged between the cooling tubes. Flow obstacles and turbulence inserts can influence the flow in the tube bundle or in the cooling tubes and improve the heat transfer between exhaust gas and coolant. WO 2015/121148 A1 further discloses a deflection element which is arranged in the coolant inlet and specifically directs the coolant to the exhaust gas inlet. DE 32 12 914 A1 discloses deflection elements which are arranged in the tube bundle between two stacks of the respective cooling tubes.
DE 10 2010 001 635 A1 discloses a wire deflector.
US 2013/0327499 A1 discloses an alternative embodiment of the deflection elements. The deflection elements can prevent the coolant from flowing out of the tube bundle too quickly.

US 2015/0260466 A1 . JP 2014-194296 A and DE 10 2014 208 259 A1 disclose generic exhaust gas recirculation coolers, each having a flow control structure. The flow guide structure engages from the annular space in the tube block and is additionally fixed to the tube block. In US 2015/0260466 A1 For this purpose, for example, a ring structure is provided, on which the flow structure is clamped. The flow control structures direct the coolant between the individual rows of pipes and thereby improve the heat transfer between the exhaust gas and the coolant. Disadvantageous catfish such flow control structures significantly increase the cost of the exhaust gas recirculation cooler and are also not modular.

The object of the invention is therefore to provide an exhaust gas recirculation cooler in which a longer and uniform exposure of the tube bundle to the coolant is made possible by an inexpensive and simple flow guide structure, and thereby the heat transfer between the coolant and the exhaust gas is improved.

This object is achieved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the general idea of diverting a coolant flowing into an exhaust gas recirculation cooler in the exhaust gas recirculation cooler with as little loss as possible to a so-called exhaust gas inlet floor and thereby achieving an increase in heat transfer in the exhaust gas recirculation cooler between a hot exhaust gas and the colder coolant. For this purpose, the exhaust gas recirculation cooler has a housing in which a plurality of cooling tubes are arranged in columns next to one another to form a row of tubes and at least two rows of tubes one above the other and spaced apart from one another to form a tube block. Exhaust gas can flow through the inside of the respective cooling tube and connects an exhaust gas inlet with an exhaust gas outlet in a gas-conducting manner. Coolant can flow around the respective cooling tube inside the housing, for which purpose the housing has a coolant inlet opening into the housing in an inlet region and a coolant outlet. The exhaust gas recirculation cooler also has an annular space which surrounds the tube block in the circumferential direction and through which the coolant can flow. The exhaust gas recirculation cooler has a flow guide arrangement for guiding the coolant inside the pipe block, which is arranged in the housing, at least in regions, against at least one of the rows of pipes.

The flow guide arrangement bears against at least one of the rows of pipes. For example, the flow guide arrangement can be arranged between the adjacent rows of pipes and can have a plurality of guide channels for guiding the coolant, such as water, between the respective adjacent rows of pipes. The guide channels can guide the coolant from the inlet region of the housing between the two rows of pipes essentially in a transverse direction orthogonal to a longitudinal direction of the pipe block and can delay an outflow of the coolant in the longitudinal direction to the coolant outlet. This enables a longer and more uniform application of the coolant to the pipe block, in particular in the hotter inlet area, and consequently also improves the heat transfer between the coolant and the exhaust gas. The flow guide arrangement can, for example, have at least one guide plate with guide channels, which is arranged between the adjacent rows of pipes and enables the coolant to be guided essentially in the transverse direction.

As an alternative or in addition, it is known that the flow-guiding arrangement can rest on one or more rows of pipes on a side of the pipe block facing the annular space and guide the coolant out of the annular space between the adjacent rows of pipes. In this way, the coolant can be prevented from flowing out of the inlet area from the coolant inlet to the coolant outlet around the pipe block, and a longer and uniform application of the coolant to the pipe block is made possible.

The flow guide arrangement can advantageously be arranged in the pipe block during the manufacture of the exhaust gas recirculation cooler. Depending on the dimensions of the exhaust gas recirculation cooler, the flow control arrangement can also be adapted accordingly. The heat transfer in the exhaust gas recirculation cooler is increased by the flow side arrangement and thereby a mechanical failure of the exhaust gas recirculation cooler due to overheating advantageously prevented.

Furthermore, it is provided that the flow guide arrangement has at least one flow guide structure, the flow guide structure being arranged at least in regions in the inlet region of the housing and engaging the pipe block from the annular space. For example, the flow guide structure can advantageously delay the coolant flowing away around the pipe block from the inlet area and enable the coolant to be guided between the adjacent rows of pipes essentially in the transverse direction. The flow guide arrangement can have a plurality of flow guide structures which engage from the annular space in the tube block on one side or on both sides opposite one another. The flow behavior of the coolant in the annular space and in the tube block can be influenced advantageously by the number, the arrangement of the flow guide structures on the tube block, the dimensions and the configuration of the flow guide structures.

According to the invention, the at least one flow guide structure has a plurality of individual wire elements, the respective wire element being provided for one row of tubes or for some of the rows of tubes. In order to facilitate fixing the respective wire element to the pipe block, the respective wire element according to the invention encompasses at least one of the rows of pipes at least in regions on a side facing the annular space. The respective wire element is thereby arranged in a clamped or form-fitting manner on one of the rows of pipes and engages in spaces between the adjacent rows of pipes from the annular space. The respective wire element can encompass several or individual rows of pipes, thereby influencing the flow pattern of the coolant in the pipe block and in the annular space.

It is advantageously provided that the flow guide structure has at least one fixing area for fixing the flow guide structure on the row of pipes and at least one flow guide area for guiding the coolant between the adjacent rows of pipes. The fixing area can, for example, fix the flow guide structure to the row of pipes in a form-fitting or non-positive manner. As a result, in particular the assembly effort of the flow guide structure on the pipe block can be considerably reduced. The coolant is passed through the pipe block through the flow guide area, the flow guide area being arranged in the inlet area of the housing and thus allowing the coolant to be guided in the pipe block from the coolant inlet. The flow pattern of the coolant in the annular space and in the tube block can be advantageously influenced by the number, the arrangement on the tube block, the dimensions and the configuration of the flow guide structures.

In a particularly advantageous manner, the fixing area and / or the flow guiding area of the flow guiding structure can be clamped between two adjacent rows of pipes. In this way, an undesired displacement of the flow guide structure within the pipe block can be prevented and a particularly secure fixing of the flow guide structure in the pipe block can be achieved.

In order to further increase the heat transfer between the coolant and the exhaust gas, it is advantageously provided that the flow-guiding region deflects the coolant flowing in from the coolant inlet to the exhaust gas inlet - that is to say to the so-called exhaust gas inlet floor. At the exhaust gas inlet, the exhaust gas to be cooled has the highest temperature and the coolant flowing in from the coolant inlet has the lowest temperature within the housing. By deflecting the coolant, a high temperature gradient between the coolant and the exhaust gas is achieved at the exhaust gas inlet consequently, heat transfer is advantageously increased. For this purpose, the flow guide area can have at least one guide channel, which is arranged essentially transversely to the longitudinal direction of the pipe block and thus enables the coolant to be deflected to the exhaust gas inlet. The guide channel can extend over the entire width or alternatively only partially in the width of the pipe block. The angle of the guide channel to the longitudinal direction or to the transverse direction of the pipe block can also be adjusted in order to influence the flow pattern of the coolant in the pipe block.

According to the invention, the flow guide structure has several individual wire elements. The wire element can be, for example, an injection molded part, an injection molded part or a wire molded part. The wire element advantageously has a small volume and only insignificantly reduces the volume of the coolant flowing in the housing. In an advantageous manner, the coolant is guided in the tube block and the volume of the coolant in the housing is retained. The wire element advantageously also has only a slight effect on the pressure loss in the coolant flow. Furthermore, the wire element can be manufactured inexpensively.

It is also advantageously provided that the fixing area and the flow guiding area are integrally formed on the wire element. For example, the fixing area can be shaped in a meandering shape or in the form of a clamp and enable the flow-guiding structure to be non-positively fixed on the pipe block. A form-fitting fixing of the fixing area, for example on impressions of the cooling pipes, is also possible. The flow area can be shaped in the form of a longer guide channel which extends essentially in the transverse direction. The flow pattern of the coolant in the pipe block can be advantageously influenced by adapting the length of the guide channel or the angle to the transverse direction of the pipe block.

In order to be able to cool the exhaust gas inlet as effectively as possible, it is provided that the flow guide arrangement has a ring structure. The ring structure is arranged in the ring space around the pipe block and, in a fluid-resistant manner, separates the inlet area within the ring space from the coolant outlet at least in some areas. In an advantageous manner, a drainage of the coolant around the pipe block from the inlet area is inhibited and the heat transfer in the inlet area is improved. The ring structure can, for example, be arranged in a recess in the housing and thus fixed on the housing. Alternatively, the ring structure can be fixed to a recess in the housing.

It is also provided that the ring structure has at least one passage opening through which the coolant can flow from the inlet area within the ring space to the coolant outlet. The passage opening can be provided, for example, on a side surface or on an angled region of the ring structure in order to at least partially allow the coolant to flow out of the inlet region. In particular, this can prevent the coolant from accumulating and thus overheating in the inlet area and the coolant pressure in the housing can be maintained.

The ring structure can advantageously be fixed resiliently and / or pretensioned on the pipe block and / or on the housing. For this purpose, the ring structure can have, for example, resilient structures formed on the ring structure Have longitudinal direction, which can advantageously protect the ring structure from mechanical loads such as vibrations.

In a development of the solution according to the invention, it is advantageously provided that the housing has a circulation space, the circulation space enclosing the tube block in the inlet region in the circumferential direction and being formed, for example, by a depression in the housing. The coolant can be collected in the circulation space before it is led into the tube block and the tube block can be additionally cooled in the inlet area. The coolant can then be guided from the circulation space between the rows of pipes in order to cool the exhaust gas. In this way, uniform application of the coolant to the pipe block can be achieved and consequently the heat transfer between the coolant and the exhaust gas in the inlet area can be increased.

It is advantageously provided that the flow guide arrangement has the ring structure and at least one flow guide structure and that at least one of the flow guide structures is integrally formed on the ring structure. The flow guide structure integrally formed on the ring structure can be designed in a particularly stable manner and the service life of the flow guide arrangement can thereby be increased.

Alternatively, it is provided that the flow guide arrangement has the ring structure and at least one flow guide structure, the ring structure encompassing at least one of the flow guide structures arranged on the pipe block. Here the flow guide structures can first be arranged in the pipe block and then the ring structure can be arranged around the pipe block.

Further important features and advantages of the invention result from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, the same reference numerals referring to the same or similar or functionally identical components.

Fig. 1

eine Teilschnittansicht eines erfindungsgemäßen Abgasrückführkühlers;

Fig. 2

eine Teilschnittansicht eines Abgasrückführkühlers mit einem Umlaufraum;

Fig. 3

eine Ansicht einer Strömungsleitanordnung, die an einem Rohrblock angeordnet ist;

Fig. 4

eine Draufsicht auf eine Strömungsleitanordnung, die an einem Rohrblock angeordnet ist;

Fig. 5

eine Ansicht einer Strömungsleitstruktur;

Fig. 6

eine Ansicht mehrerer Strömungsleitstrukturen, die zu einer Strömungsleitanordnung angeordnet sind;

Fig. 7

eine Ansicht eines Abgasrückführkühlers mit einer Ringstruktur;

Fig. 8

eine Ansicht eines Abgasrückführkühlers mit einer Ringstruktur und mit mehreren Strömungsleitstrukturen.

It shows, each schematically

Fig. 1

a partial sectional view of an exhaust gas recirculation cooler according to the invention;

Fig. 2

a partial sectional view of an exhaust gas recirculation cooler with a circulation space;

Fig. 3

a view of a flow guide assembly which is arranged on a pipe block;

Fig. 4

a plan view of a flow guide arrangement which is arranged on a pipe block;

Fig. 5

a view of a flow guide structure;

Fig. 6

a view of a plurality of flow guide structures which are arranged to form a flow guide arrangement;

Fig. 7

a view of an exhaust gas recirculation cooler with a ring structure;

Fig. 8

a view of an exhaust gas recirculation cooler with an annular structure and with several flow guide structures.

Fig. 1 shows a partial sectional view of an exhaust gas recirculation cooler 1 according to the invention. The exhaust gas recirculation cooler 1 has a housing 2 in which a plurality of cooling tubes 3 are arranged in columns next to one another to form a row of tubes 4 and at least two rows of tubes 4 one above the other and spaced apart from one another to form a tube block 5. Exhaust gas can flow through the respective cooling tube 3 and connects an exhaust gas inlet 6 to an exhaust gas outlet 7 in a gas-conducting manner. The individual cooling tubes 3 are connected to an exhaust gas inlet floor 6a at the exhaust gas inlet 6 and to an exhaust gas outlet floor 7a at the exhaust gas outlet 7. Outside, the respective cooling tube 3 can be flowed around by the coolant within the housing 2, for which purpose the housing 2 has a coolant inlet 9 opening into the housing 2 in an inlet area 8 and a coolant outlet 10. The exhaust gas recirculation cooler 1 also has an annular space 11 which surrounds the tube block 5 in the circumferential direction and through which the coolant can flow. According to the invention, the exhaust gas recirculation cooler 1 has a flow guide arrangement 12 for guiding the coolant inside the tube block 5, which is arranged in the housing 2, at least in regions, against at least one of the tube rows 3.

In this exemplary embodiment, the flow guide arrangement 12 has an annular structure 13 which is arranged in the annular space 11 around the tube block 5.

The ring structure 13 fluid-tightly separates the inlet area 8 within the annular space 11 from the coolant outlet 10, so that the coolant does not flow out around the pipe block 5 from the inlet area 8, and the heat transfer in the inlet area 8 is improved. To further improve the heat transfer between the exhaust gas and the coolant, the housing 2 has a circulation space 14 which surrounds the pipe block 5 in the inlet region 8 in the circumferential direction.

Fig. 2 shows a partial sectional view of the exhaust gas recirculation cooler 1 with the circulation space 14. For the sake of clarity, the middle cooling tubes 3 in the row of tubes 4 are shown in dashed lines. In the circulation space 14, the coolant is dammed up before leading to the exhaust gas inlet 6 and the pipe block 5 is cooled longer in the inlet area 8. From the circulation space 14, the coolant can then be guided into the tube block 5, as indicated by arrows. In this way, uniform application of the coolant to the pipe block 5 can be achieved and consequently the heat transfer between the coolant and the exhaust gas in the inlet area 8 can be increased.

Fig. 3 shows a view and Fig. 4 a plan view of the flow guide arrangement 12, which is arranged on the pipe block 5. The flow guide arrangement 12 has two flow guide structures 15, which are wire elements 16 in this exemplary embodiment. The flow guide structures 15 can be arranged in regions in the inlet region 8 of the housing 2 and can engage in the tube block 5 from the annular space 11. The flow guide structures 15 each have a fixing area 17 for fixing the respective flow guide structure 15 to the respective row of pipes 4 and a flow guide area 18 for guiding the coolant between the adjacent rows of pipes 4. The fixing area 17 encompasses the respective row of tubes 4 and fixes the flow guide structure 15 to the tube block 5 by clamping.

In order to increase the heat transfer between the coolant and the exhaust gas, the flow guiding region 18 deflects the coolant flowing from the coolant inlet 9 to the exhaust gas inlet 6. For this purpose, the flow area 18 of the respective flow guide structure 15 has two guide channels 19, which essentially extend in a transverse direction 20 to a longitudinal direction 21 of the pipe block 5. The respective guide channel 19 has - as in Fig. 4 to see - an angle to the transverse direction 20 and can deflect the coolant to the exhaust gas inlet 6 and the exhaust gas inlet floor 6a. The angle of the guide channel 19 to the transverse direction 20 or to the longitudinal direction 21 of the tube block 5 and the length of the guide channel 19 can be adjusted in order to influence the flow pattern of the coolant in the tube block 5. By deflecting the coolant, the flow guide structure 15 delays the coolant from flowing out of the inlet area 8, so that the heat transfer between the coolant and the exhaust gas can be increased.

In Fig. 5 is a single wire element 16 of the flow guide structure 15 and in Fig. 6 A total of four wire elements 16 of the flow guide structure 15 are arranged to the flow guide arrangement 12. The respective wire element 16 can be, for example, an injection molded part, an injection molded part or a wire molded part. The fixing area 17 and the flow guiding area 18 are integrally formed on the wire element 16. The wire element 16 can thus be produced inexpensively. The fixing area 17 of the wire element 16 is shaped in a meandering manner and enables the wire element 16 to be non-positively attached to the tube row 4. The flow guiding area 18 of the wire element 16 has two guide channels 19, through which the coolant can be guided between the adjacent tube rows 4. The flow pattern of the coolant in the tube block 5 can be advantageous by changing the length and the width of the guide channel 19 and the angle to the transverse direction 20 can be influenced.

Fig. 7 shows a view of the exhaust gas recirculation cooler 1 with the ring structure 13 of the flow guide arrangement 12. The ring structure 13 is arranged in the ring space 11 around the pipe block 5 and separates the inlet area 8 within the ring space 11 from the coolant outlet 10 in a fluid-resistant manner Drainage of the coolant around the tube block 5 from the inlet area 8 is inhibited and the heat transfer in the inlet area 8 is improved. In order to prevent the coolant from accumulating and thus overheating in the inlet area 8, the ring structure 13 has at least one passage opening 22. The passage opening 22 is arranged in an angled area 23 of the ring structure 13 and enables the coolant to flow out of the inlet area 8 within the annular space 11. In order to influence the flow of the coolant out of the inlet area 8, the ring structure 13 can be several in size and have passage opening 22 different in position.

In Fig. 8 A view of the exhaust gas recirculation cooler 1 is shown with the flow guide arrangement 12, which has the ring structure 13 and the flow guide structures 15. The ring structure 13 encompasses the flow guide structures 15 arranged on the pipe block 5, as a result of which an additional fixing of the flow guide structures 15 in the pipe block 5 is made possible. The flow guide arrangement 12 can already be arranged in the tube block 5, for example, during the manufacture of the exhaust gas recirculation cooler 1. Depending on the dimensions of the exhaust gas recirculation cooler 1, the flow guide arrangement 12 can also be adapted accordingly. The heat transfer in the exhaust gas recirculation cooler 1 according to the invention is improved by the flow guide arrangement 12 and thereby advantageously both mechanical failure of the exhaust gas recirculation cooler 1 as a result of overheating and also increases the efficiency of the exhaust gas recirculation cooler 1.

Claims (12)

1. Exhaust gas recirculation cooler (1) for an internal combustion engine, in particular a motor vehicle,

   - wherein the exhaust gas recirculation cooler (1) comprises a housing (2), in which multiple cooling pipes (3) are arranged next to one another and form a pipe row (4) and at least two pipes series (4) are arranged above one another and spaced apart from one another to form a pipe block (5),

   - wherein the exhaust gas can flow internally through the respective cooling pipe (3), which connects an exhaust gas inlet (6) in a gas-conducting manner to an exhaust gas outlet (7), while coolant can flow externally through the cooling pipe within the housing (2),

   - wherein the housing (2) comprises a coolant inlet (9) in an inlet region (8) opening into the housing (2) and a coolant outlet (10), and

   - wherein the exhaust gas recirculation cooler (1) comprises an annular space (11) surrounding the pipe block (5) in the circumferential direction, through which the coolant can flow,

   - wherein the exhaust gas recirculation cooler (1) comprises a flow conducting arrangement (12) for conducting the coolant in the interior of the pipe block (5), which is arranged in the housing (2) abutting at least region-wise at least one of the pipe row (4),

   - wherein the flow conducting arrangement (12) comprises at least one flow conducting structure (15), wherein the flow conducting structure (15) is arranged at least region-wise in the inlet region (8) of the housing (2) and from the annular space (11) engages in the pipe block (5),
   characterised in that
   the at least one flow conducting structure (15) comprises multiple individual wire elements (16), wherein the respective wire element (16) is provided for respectively one pipe row (4) or for respectively some of the pipe row (4), and
   that the respective wire element of the flow conducting structure (15) encompasses the associated pipe row (4) or associated pipe rows (4) at least region-wise on a side facing the annular space (11) and from the annular space (11) engages in spaces with the adjacent pipe rows (4) and thereby fixes the respective wire element (16) in a clamping or positive-locking manner to the associated pipe row (4) or to the associated pipe rows (4) of the pipe block (5).
2. Exhaust gas recirculation cooler according to claim 1, characterised in that the flow conducting structure (15) comprises at least one fixing region (17) for fixing the flow conducting structure (15) to the pipe row (4) and at least one flow conducting region (18) for conducting the coolant between the adjacent pipe rows (4).
3. Exhaust gas recirculation cooler according to claim 2, characterised in that the fixing region (17) and/or the flow conducting region (18) of the respective wire element (16) of the flow conducting structure (15) is/are clamped between two adjacent pipe rows (4).
4. Exhaust gas recirculation cooler according to claim 2 or 3, characterised in that the flow conducting region (18) deflects the coolant flowing from the coolant inlet (9) to the exhaust gas inlet (6).
5. Exhaust gas recirculation cooler according to any one of claims 2 to 4, characterised in that the fixing region (17) and the flow conducting region (18) are integrally formed on the wire (16).
6. Exhaust gas recirculation cooler according to any one of the preceding claims, characterised in that the respective wire elements (16) is an injection moulded part, a diecast part or a wire stamped part.
7. Exhaust gas recirculation cooler according to any one of the preceding claims, characterised in that the flow conducting arrangement (12) comprises an annular structure (13), wherein the annular structure (13) is arranged in the annular space (11) around the pipe block (5), and wherein the annular structure (13) separates at least section-wise the inlet region (8) within the annular space (11) in a fluid-tight manner from the coolant outlet (9).
8. Exhaust gas recirculation cooler according to claim 7, characterised in that the annular structure (13) comprises at least one outlet opening (22), through which the coolant can flow from the inlet region (8) within the annular space (11) to the coolant outlet (10).
9. Exhaust gas recirculation cooler according to claim 7 or 8, characterised in that the annular structure (13) is fixed resiliently and/or in a biased manner on the pipe block (5) and/or on the housing (2).
10. Exhaust gas recirculation cooler according to any one of the preceding claims, characterised in that the housing (2) comprises a circulation space (14), wherein the circulation space (14) surrounds the pipe block (5) in the inlet region (8) in the circumferential direction.
11. Exhaust gas recirculation cooler according to claims 7 to 9, characterised in that the flow conducting arrangement (12) comprises the annular structure (13) and at least one flow conducting structure (15), and that at least one of the flow conducting structures (15) is formed integrally on the annular structure (13).
12. Exhaust gas recirculation cooler according to any one of claims 7 to 9, characterised in that the flow conducting arrangement (12) comprises the annular structure (13) and at least one flow conducting structure (15), wherein the annular structure (13) encompasses at least one of the flow conducting structures (15) arranged on the pipe block (5).

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