EP2667007A1 - Heat exchanger, exhaust gas recirculation system and internal combustion engine - Google Patents

Abstract

The heat exchanger (10) has a heat exchanger block (11) that performs heat exchange between work fluid (AF) such as exhaust gas or air and cooling fluid (KF) such as coolant. Working fluid filters are provided between the working fluid connecting lines (14.1,14.2). The working fluid connecting lines are connected to the heat exchanger block. Pick-up flange (18) is provided in each connecting line and is provided with a diffuser. An independent claim is included for exhaust gas recirculation system.

Description

The invention relates to a heat exchanger for heat exchange between a working fluid on the one hand and a cooling fluid on the other hand and with a working fluid filter, wherein the heat exchanger comprises: a heat exchanger block for implementing the heat exchange; at least one connecting line for the working fluid. The invention also leads to a favorable exhaust gas recirculation system and an internal combustion engine, in particular a diesel internal combustion engine.

The reduction of nitrogen oxides in exhaust gases of an internal combustion engine can be achieved particularly effectively in the context of exhaust gas recirculation. For this purpose, the output side working fluid, in particular an exhaust gas, the internal combustion engine in compressed and cooled form, the internal combustion engine supplied as an input-side working fluid, possibly together with a charge air. This approach has been in the context of increasingly restrictive emission standards especially for a diesel internal combustion engine proved to be important.

For the cooling of the working fluid is a regularly mentioned heat exchanger. The compression of the working fluid is achieved by means of a compressor. It has been found that the working fluid acted upon parts of a compressor are susceptible to wear. This applies in particular to diesel internal combustion engines whose exhaust gas to be used as the working fluid is particle-laden to a relatively high degree. The particles can not only settle on surfaces of the compressor and affect its function, but also wear so much by their impulse action applied to working fluid surfaces of the compressor that it may need to be replaced early. The particulate charge of the exhaust gas can persist despite a diesel particulate filter, as it is subject to aging and especially in the context of regeneration increased particulate entry into the exhaust gas can not be prevented.

To remedy such problems is in DE 69 732 534 T2 an exhaust gas recirculation system has been proposed in which a filter is disposed downstream of a heat exchanger for particulate reduction, the filter having an inlet end and an outlet end, the inlet end of the filter being connected to an outlet end of the heat exchanger and the outlet end of the filter connectable to an intake tube of the engine is. Such a heat exchanger of the type mentioned thus provides outside of the heat exchanger before a working fluid filter, which requires additional space and which is fluidically associated with relatively high pressure drop.

It would be desirable to have an improved filter design without sacrificing filter performance.

At this point, the invention begins, whose task is to provide a device by means of which the particle load in a working fluid of an internal combustion engine can be reduced and in which nevertheless a space requirement for the filter is kept relatively small or uncritical. In particular, a fluidically advantageous integration of the filter is to take place, advantageously with a comparatively low pressure loss. In particular, the handling of the filter should also be possible in a simplified manner.

Regarding the device, the object is achieved by the invention by means of a heat exchanger of the type mentioned, is mounted according to the invention for integration of the working fluid filter in the heat exchanger of the working fluid filter between heat exchanger block on the one hand and connecting line on the other hand, wherein the connecting line connected to the heat exchanger block

The heat exchanger block preferably has a core with a number of flow passages through which the first fluid can flow, and a chamber receiving the flow passages, through which the second fluid can flow, in a housing. However, the structure of the heat exchanger block is not limited to this preferred form. Thus, the core may also have a bottom which receives the flow channels and keeps them frame-like spaced. In principle, a connecting line, following the concept of the invention, can be fastened to the housing and / or to the floor. In a particularly advantageous manner, the heat exchanger block accordingly have: a core for separate heat exchanging guidance of the working fluid and the cooling fluid; a core receiving, permeable by the cooling fluid housing; wherein the working fluid filter between the housing or core on the one hand and connecting line on the other hand is mounted, wherein the connecting line is connected to the housing or core.

It has been found that a working fluid filter integrated in this manner in the heat exchanger is accommodated in a particularly space-saving manner. The heat exchanger can be offered together with the working fluid filter as a module. As a result, a significant reduction in space requirements compared to the prior art is possible. It has also been shown that the concept of the invention enables a fluidically particularly advantageous integration of the working fluid filter in the working fluid guide. In addition, a working fluid filter is not only particularly easy to replace, but also relatively easy to permanently remove in the event that no working fluid filter in the heat exchanger module is required. This is due to the fact that the connecting line is connected to the heat exchanger block and if necessary, the working fluid filter just between the heat exchanger block on the one hand and the connecting line on the other hand can be omitted - or held if necessary.

Advantageous developments of the invention can be found in the dependent claims and specify in detail advantageous ways to realize the above-described concept within the scope of the task, as well as with regard to further advantages.

The connection line is particularly advantageously formed with a connection flange. A connecting flange substantially facilitates the connection to the heat exchanger block with attachment of the working fluid filter. Advantageously, the connection flange is formed with a diffuser. The diffuser basically has flow comparison properties for the working fluid. In the present case, moreover, the diffuser has a sufficient internal space which is suitable for being able to attach a filter shaped to this effect.

In principle, the connection line can be an inlet and / or outlet line. It has proved to be particularly advantageous that the working fluid filter is mounted on the working fluid inlet side of the heat exchanger between the heat exchanger block and a supply line. In principle, moreover, additionally or alternatively, the working fluid filter can also be mounted on the working fluid outlet side of the heat exchanger between the heat exchanger block and a discharge line.

In the context of a first variant, it has proved to be advantageous that the working fluid filter has a filter surface which is flat. A flat filter surface has an advantageously small space requirement and is advantageous in terms of flow or in particular has a comparatively low pressure loss.

In a second variant, the working fluid filter may have a filter surface which is non-flat. In particular, this may be a curved filter surface, preferably a dome-shaped filter surface. The shape of the curved filter surface can be designed overall such that it has a diffuser-like effect. Basically, the shape of the filter surface can be designed fluidically optimized.

In particular, the working fluid filter is designed for axial flow with advantage. As a result, the lowest possible pressure loss in the working fluid filter is achieved, for example by largely avoiding a radial flow component in the working fluid filter.

In a particularly preferred embodiment, the working fluid filter has a flange which is mounted between a flange of the connecting line and a flange of the heat exchanger core. Due to the flange connection of the working fluid filter, the same can be attached, in particular fixed, under positive locking, frictional connection or the like between the flanges of the heat exchanger core or the connection line. The flange can be free of connecting means or have suitable connecting means, if necessary also holes or the like. For connecting means.

Thus, the working fluid filter can be realized with a flange in the form of a gasket, particularly in the form of a metallic gasket particularly advantageous. Thus, the filter surface of the working fluid filter can be advantageously connected by a joint connection with the flange. A joint connection can be provided in particular in the form of a welding and / or solder joint. Alternatively, the working fluid filter with filter surface and flange can also be made in one piece or the filter surface can be frictionally, for example, clamped, connected to the flange. When choosing the connection, the pressure and flow conditions at the installation point of the working fluid filter can be suitably taken into account.

In the context of a second particularly preferred development, the flange of the working fluid filter can be attached by means of a tongue and groove connection between a connecting flange of the connecting line and a counter flange of the heat exchanger block. Thus, the flange may have a spring and / or groove as a connecting means. The flange can act like a seal. However, the sealing effect is not absolutely necessary. The tongue and groove connection has the advantage that the working fluid filter can be held comparatively securely and avoiding more complex connection means between the connecting line and the heat exchanger block.

• einen Partikelfilter für ein Arbeitsfluid stromabwärtig einer Arbeitsfluidauslassleitung einer Brennkraftmaschine;
• einen Wärmetauscher gemäß dem Konzept der Erfindung stromabwärtig des Partikelfilters; und
• einen Verdichter für das Arbeitsfluid stromabwärtig des Wärmetauschers und stromaufwärtig vor einer Arbeitsfluideinlassleitung einer Brennkraftmaschine.

Regarding the device, the invention leads to the solution of the problem also to an exhaust gas recirculation system comprising:

• a particulate filter for a working fluid downstream of a working fluid outlet line of an internal combustion engine;
• a heat exchanger according to the concept of the invention downstream of the particulate filter; and
• a compressor for the working fluid downstream of the heat exchanger and upstream of a working fluid inlet line of an internal combustion engine.

In the context of the exhaust gas recirculation system, the heat exchanger is advantageously designed as a low-pressure heat exchanger. It has been found that, especially in the low pressure range of exhaust gas recirculation, a working fluid filter can be integrated in a space-saving manner in the heat exchanger according to the concept of the invention.

Accordingly, the concept of the invention for solving the problem also leads to an internal combustion engine, in particular a diesel internal combustion engine, with an exhaust gas recirculation system of the aforementioned type.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily to scale the embodiments, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes may be made in the form and detail of an embodiment without departing from the general idea of the invention. The disclosed in the description, in the drawing and in the claims features of the invention may be essential both individually and in any combination for the development of the invention. In addition, fall within the scope of the invention, all combinations of at least two of the disclosed in the description, the drawings and / or the claims Characteristics. The general idea of the invention is not limited to the exact form or detail of the preferred embodiment shown and described below or limited to an article which would be limited in comparison to the subject matter claimed in the claims. For the given design ranges, values within the stated limits should also be disclosed as limit values and be arbitrarily usable and claimable. For simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar function.

Fig. 1A, Fig. 1B:

eine perspektivische Darstellung einer ersten bevorzugten Ausführungsform eines Wärmetauschers in einer Darstellung mit Diffusoranschlussleitung (A) und ohne Diffusoranschlussleitung (B) zur Ansicht des Arbeitsfluid-Filters;

Fig. 2A, Fig. 2B:

eine perspektivische Ansicht einer zweiten bevorzugten Ausführungsform eines Wärmetauschers in einer Darstellung mit Diffusoranschlussleitung (A) und ohne Diffusoranschlussleitung (B) zur Ansicht des Arbeitsfluid-Filters, in Ansicht I und vergrößert in II;

Fig. 3:

eine perspektivische Darstellung des konstruktiven Details zur Integration eines Arbeitsfluid-Filters im Wärmetauscher gemäß einer ersten Variante;

Fig. 4:

eine perspektivische Ansicht eines ersten Arbeitsfluid-Filters der Fig. 3 mit flacher Filterfläche;

Fig. 5:

eine perspektivische Ansicht eines zweiten Arbeitsfluid-Filters mit gewölbter Filterfläche;

Fig. 6:

ein konstruktives Detail zur Integration eines zweiten ArbeitsfluidFilters der Fig. 5 im Wärmetauscher gemäß einer zweiten Variante.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing; this shows in:

1A, 1B:

a perspective view of a first preferred embodiment of a heat exchanger in a representation with diffuser connection line (A) and without diffuser connection line (B) for viewing the working fluid filter;

Fig. 2A, Fig. 2B:

a perspective view of a second preferred embodiment of a heat exchanger in a representation with diffuser connection line (A) and without diffuser connection line (B) for viewing the working fluid filter, in view I and enlarged in II;

3:

a perspective view of the structural details for the integration of a working fluid filter in the heat exchanger according to a first variant;

4:

a perspective view of a first working fluid filter of Fig. 3 with flat filter surface;

Fig. 5:

a perspective view of a second working fluid filter with a curved filter surface;

Fig. 6:

a constructive detail for the integration of a second working fluid filter of Fig. 5 in the heat exchanger according to a second variant.

Fig. 1A shows a heat exchanger 10 in the form of a low-pressure heat exchanger for incorporation into an exhaust gas recirculation system downstream of a particulate filter and upstream of a compressor for the working fluid. The heat exchanger 10 has a heat exchanger block 11 with a housing 12 and a housing 12, not shown core for separate and heat exchanging guidance of a working fluid AF and a cooling fluid KF. The housing 12 which can be flowed through by the cooling fluid KF is supplied to it via inlet and outlet ports 13.1, 13.2, wherein the cooling fluid KF is shown symbolically by arrows. The working fluid AF, which is also shown symbolically by arrows, is provided to a number of flow passages 21 (FIG. Fig. 3 ) fed in the block and thus cooled by cooling fluid KF. The working fluid AF is supplied to the heat exchanger 10 via a first connecting line 14.1 in the form of a feed line and discharged via a second connecting line 14.2 in the form of a discharge line. In the present case, the connection line 14.1 has a diffuser 15, an expansion element 16 in the form of a bellows and an upstream connecting flange 17 facing away from the heat exchanger and a connecting flange 18 facing the heat exchanger 10. According to the concept of the invention, a working fluid filter 1 is integrated in the heat exchanger 10, which is mounted between the heat exchanger block 11 on the one hand and the connecting line 14.1 on the other hand, wherein the connecting line 14.1 is connected to the heat exchanger block 11. The purpose of the heat exchanger 10 facing connecting flange 18 of the connecting line 14.1. The diffuser 15 serves one flow-equal supply of the working fluid - in the present case in the form of exhaust gas of a diesel internal combustion engine - from the connecting line 14.1 and is formed in the form of a funnel-like element.

Fig. 1 B shows the same heat exchanger 10 without the connection line 14.1, so that the working fluid filter 1 can be seen. The working fluid filter 1 has a flat filter surface 2 and a in Fig. 1A recognizable flange 3, which flange 3 is clamped between the connecting flange 18 of the connecting line 14.1 and the mating flange 19 of the heat exchanger block 11 by means of screw S.

In the present case, the working fluid filter 1 is formed with a flange 3 in the form of a metallic sealing collar, wherein the filter surface 2 is welded into the flange 3. In a presently particularly advantageous manner thus the working fluid filter 1 is provided on the one hand with a filter function and on the other with a sealing function. Furthermore, the filter surface 2 is advantageously not only designed to save space in a space-saving manner, but can also be effectively accommodated in the funnel-shaped interior of the funnel of the diffuser 15. In addition, the flat design of the filter surface 2 is streamlined in the area of equalization of the flow of the working fluid, i. in the funnel-shaped interior of the diffuser 15, arranged. The flat filter surface 2 is flowed through axially by the working fluid AF, which results in a particularly low pressure loss. The realized in the present embodiment, the working fluid filter 1 can not only easily replace, but also if necessary permanently removed that instead of a gasket with filter, namely the working fluid filter 1, only a simple gasket without filter is used.

Fig. 2A and Fig. 2B show analogously a second embodiment of a heat exchanger 20 - again in Fig. 2A with a connection line 14.1 and in Fig. 2B without a connecting cable 14.1. In Fig. 2B In addition, the view I on the working fluid filter 1 is shown enlarged in II.

The heat exchanger 20 differs from the heat exchanger 10 in the arrangement of the inlet and outlet nozzles 13.1, 13.2 for the cooling fluid KF. In addition, the connection line 14.1 as a supply line and the connecting line 14.2 with a diffuser 15.1, 15.2 is set up.

Fig. 2B again shows the working fluid filter 1 with a flat filter surface 2, which is flowed through axially, and with a formed in the form of a gasket flange 3, which is analogous to the embodiment of a heat exchanger 10 in Fig. 1A, Fig. 1B , is clamped with screw S between the connection flange 18 of the connection line 14.1 and the mating flange 19 of the heat exchanger block 11.

In the present case, a gasket 4 is clamped between the heat exchanger block 11 and the connection line 14.2, namely the corresponding flanges of the outlet side, on the working fluid outlet side of the heat exchanger 20. The gasket 4 may - as needed - similar to the gasket 3 wear a filter surface or be used without a filter surface. In this case, the embodiment of a heat exchanger 20 can thus be a working fluid filter 1 as needed integrate the input side of the heat exchanger 20 and the output side of the heat exchanger 20.

Fig. 3 shows the constructive detail of a Fig. 1A, Fig. 1B shown heat exchanger 10 without housing 12. This will in addition to the - in Fig. 4 enlarged and perspectively illustrated working fluid filter 1 - the flow channels 21 recognizable, one of which is representatively represented as a flat tube. The flow channels 21 formed as flat tubes are each held in a bottom 22 of the heat exchanger core, which for example Having trained as passages openings 23 for receiving a flat tube.

Fig. 5 shows a to the working fluid filter 1 of Fig. 4 alternative embodiment of a working fluid filter 5.1 with a curved filter surface 6 and a simple flange 7, which also has openings 8. These can be penetrated by aforementioned screw connections S during installation of the working fluid filter 5, for example in a heat exchanger 10 or in a heat exchanger 20. The curved filter surface 6 of the working fluid filter 5.1 has the advantage that this can take over diffuser function and thus contributes to the flow equalization.

An exemplary installation possibility of a slightly modified working fluid filter 5.2 on an output side of a heat exchanger is in Fig. 6 shown. In view I the Fig. 6 It can be seen that the working fluid filter 5.2 is also flowed through axially and a diffuser-like effect for the working fluid AF is effected via the curved filter surface 6. In view II, the shape of the working fluid filter 5.2, which is varied in the region of the flange 7, can be seen enlarged. The working fluid filter 5.2 has in the region of the flange 7, a spring 9, which, as from view II of Fig. 6 can be seen engages in a groove 29 of a flange 18 of a connecting line, so that the spring 9 in engagement with the groove 29, a tongue and groove connection 24 is available. The tongue and groove connection 24 allows a particularly safe and yet easy integration of the working fluid filter 5.2 in the heat exchanger.

LIST OF REFERENCE NUMBERS

1

Working fluid filter

2

flat filter surface

3

flange

4

gasket

5.1, 5.2

Working fluid filter

6

curved filter surface

7

flange

8th

hole

9

feather

10

heat exchangers

11

heat exchanger block

12

casing

13.1

Inlet, neck

13.2

Outlet nozzle, neck

14.1

connecting cable

14.2

connecting cable

15, 15.1, 15.2

diffuser

16

expansion element

17

the connecting flange facing away from the heat exchanger

18

the heat exchanger facing flange

19

counterflange

20

heat exchangers

21

flow channel

22

ground

23

openings

24

Tongue and groove

29

groove

KF

cooling fluid

AF

working fluid

S

screw

Claims (15)

Heat exchanger (10, 20), in particular low-pressure heat exchanger, for heat exchange between a working fluid (AF) on the one hand, in particular an exhaust gas and / or a charge air, and a cooling fluid (KF) on the other hand, in particular a coolant, and with a working fluid filter (1, 5, 5.1, 5.2) wherein the heat exchanger (10, 20) comprises: - A heat exchanger block (11) for implementing the heat exchange; - At least one connecting line (14.1, 14.2) for the working fluid (AF); characterized in that for integration of the working fluid filter (1, 5, 5.1, 5.2) in the heat exchanger (10, 20), the working fluid filter (1, 5, 5.1, 5.2) between the heat exchanger block (11) on the one hand and connecting line (14.1 , 14.2) is mounted on the other hand, wherein the connecting line (14.1, 14.2) is connected to the heat exchanger block (11). Heat exchanger (10, 20) according to claim 1, characterized in that the heat exchanger block (11) comprises: - A core for separate and heat exchanging leadership of the working fluid (AF) and the cooling fluid (KF); - A core receiving, by the cooling fluid (KF) through-flow housing (12);
wherein the working fluid filter (1, 5, 5.1, 5.2) between the housing (12) or core on the one hand and connecting line (14.1, 14.2) on the other hand is mounted and wherein the connecting line (14.1, 14.2) on the housing (12) or core connected. Heat exchanger (10, 20) according to claim 1 or 2, characterized in that the connection line is formed with a connection flange (18), in particular with a connection flange (18) with a diffuser (15, 15.1, 15.2). Heat exchanger (10, 20) according to one of claims 1 to 3, characterized in that the connecting line is a supply and / or discharge line (14.1, 14.2). Heat exchanger (10, 20) according to one of claims 1 to 4, characterized in that the working fluid filter (1, 5, 5.1, 5.2) on working fluid inlet side of the heat exchanger (10, 20) between a housing (12) and a supply line ( 14.1) is attached. Heat exchanger (10, 20) according to one of claims 1 to 5, characterized in that the working fluid filter (1, 5, 5.1, 5.2) on Arbeitsfluidauslassseite of the heat exchanger (10, 20) between the housing (12) and a discharge line (14.2 ) is attached. Heat exchanger (10, 20) according to one of claims 1 to 6, characterized in that the working fluid filter (1, 5, 5.1, 5.2) has a filter surface (2) which is formed flat. Heat exchanger (10, 20) according to one of claims 1 to 7, characterized in that the working fluid filter (1, 5, 5.1, 5.2) has a filter surface (6), the non-flat, in particular with a curved filter surface (6 ), preferably with a dome-shaped filter surface (6) is formed. Heat exchanger (10, 20) according to one of claims 1 to 8, characterized in that the working fluid filter (1, 5, 5.1, 5.2) is designed for axial flow. Heat exchanger (10, 20) according to one of claims 1 to 9, characterized in that the working fluid filter (1, 5, 5.1, 5.2) has a flange (3, 7) which between a connection flange (18) of the connecting line ( 14.1, 14.2) and a counter flange (19) of the heat exchanger block (11) is mounted. Heat exchanger (10, 20) according to one of claims 1 to 10, characterized in that the working fluid filter (1, 5, 5.1, 5.2) has a flange (3, 7) in the form of a gasket, in particular in the form of a metallic gasket , Heat exchanger (10, 20) according to one of claims 1 to 11, characterized in that a filter surface (2, 6) of the working fluid filter (1, 5, 5.1, 5.2) by a joint connection, in particular welding and / or soldering, or integral or non-positive, in particular clamping, with a flange (3, 7) of the working fluid filter is connected. Heat exchanger (10, 20) according to one of claims 1 to 12, characterized in that a flange (3, 7) of the working fluid filter (1, 5, 5.1, 5.2) by means of a tongue and groove connection (24) between a connecting flange (18) of the connecting line (14.1, 14.2) and a counter flange (19) of the heat exchanger core (11) is mounted Exhaust gas recirculation system comprising: a particulate filter for a working fluid (AF) downstream of a working fluid outlet conduit of an internal combustion engine; a heat exchanger (10, 20) according to any preceding claim downstream of the particulate filter; a compressor for the working fluid (AF) downstream of the heat exchanger (10, 20) and upstream of a working fluid inlet line of an internal combustion engine. Internal combustion engine, in particular diesel internal combustion engine, with an exhaust gas recirculation system according to claim 14.

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