EP3203173A1 - Exhaust gas heat exchanger - Google Patents

Abstract

The present invention relates to an exhaust gas heat exchanger (1) with a heat transfer area (2), with a bypass channel (3) bypassing the heat exchanger region (2), - With a bypass valve (4), which, depending on the position, an exhaust gas stream (5) between the heat exchanger region (2) and the bypass channel (3) divides, is essential to the invention, in that a stack disk cooler (6) with a plurality of stack disks (7, 7 ') is arranged in the heat exchanger region (2), - That the bypass channel (3) attached to an outer stacking disc (7 ') of the Stapelscheibenkühlers (6), in particular soldered.

Description

The present invention relates to an exhaust gas heat exchanger with a heat exchanger region and a bypass channel bypassing it according to the preamble of claim 1.

In order to make an exhaust gas recirculation during a cold start of an internal combustion engine, a bypass channel is usually used in conventional exhaust gas heat exchangers. This is partly housed in the exhaust gas heat exchanger, but partly also mounted externally thereto. The bypass channel has hitherto been designed as a single tube with surrounding knitwear or as a double tube, whereby a thermal insulation is to be achieved. As a result, the hot exhaust gas can bypass the cooling path during the cold start process and thereby bring the internal combustion engine and downstream oxidation catalysts to their operating temperature more quickly. As a result, it is possible in particular to reduce the nitrogen oxide emission which is still comparatively high during the cold start, and to reduce the fuel consumption more quickly by a faster heating of the internal combustion engine.

From the date of registration not yet published DE 10 2014 222 158 A1 is a generic heat exchanger with a heat exchanger area and this bypass bypass known. Also, the known heat exchanger on a bypass valve which divides depending on the position of an incoming exhaust gas flow between the heat exchanger region and the bypass channel.

From the DE 10 2006 033 313 A1 a heat exchanger with flow channels is known, which can be traversed by a common first outlet to a common first outlet of a first fluid. The heat exchanger also has a housing which receives the flow channels in itself and flows through by a second fluid from a second inlet region to a second outlet region. The flow channels have a flat cross-section and are in fluid communication with each other.

From the DE 10 2008 014 170 A1 a heat exchanger is known which comprises a bypass channel for guiding an exhaust gas and / or a charge air in a tubular body. In order to be able to reduce an undesirable heat exchanger between the bypass channel and the heat exchanger, this is isolated by a fiber material relative to the heat exchanger.

From the DE 101 42 539 A1 Also, an exhaust heat exchanger for transferring heat between the exhaust gas of an internal combustion engine and a coolant is known, which has a housing, an exhaust gas inlet opening and an exhaust gas outlet opening and a heat transfer area encloses. In the case a through-flow of at least a partial flow of the exhaust gas bypass is integrated, which is thermally insulated from the coolant, wherein the bypass is double-walled.

In general, the known from the prior art Abgaswärmeübertragern with integrated bypass channel the problem that they are no longer meet the ever-increasing performance requirements for the heat transfer.

The present invention therefore deals with the problem of providing an improved or at least one alternative embodiment for an exhaust gas heat exchanger of the generic type, which is characterized in particular by an increased performance.

This problem is solved 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, in a known per se exhaust gas heat exchanger with a heat exchanger region and a bypass channel bypassing them now for the first time instead of previously used in the heat exchanger region tube bundle heat exchanger now use stacked disc cooler. The exhaust gas heat exchanger according to the invention also has a bypass valve which, depending on the position, divides an incoming exhaust gas flow between the heat exchanger region and thus the stacked plate radiator and the bypass duct arranged there. In the heat exchanger region, as mentioned, the stacked-plate radiator is arranged according to the invention with a plurality of stacking disks, the bypass duct being attached, in particular soldered, to an outer, in particular an uppermost, stacking disk of the stacked-disk radiator. The exhaust gas heat exchanger according to the invention has a significantly increased performance, which can not be achieved with conventional tube bundle coolers. In contrast to previously known from the prior art shell-and-tube heat exchangers, the exhaust gas heat exchanger according to the invention has no housing in which the bypass channel is integrated, but this is simply soldered to the outside, that is the top or bottom stacking disk. As a result, the bypass channel according to the invention is coupled on three sides with the environment and not with the heat exchanger area, which in itself a significantly improved energy decoupling can be created to heat exchanger area, as in previously known from the prior art exhaust gas heat exchangers with integrated tube bundle cooler in a housing and bypass channel was even possible.

In an advantageous development of the solution according to the invention, the bypass channel is formed by a tube. This represents a particularly simple construction of the bypass channel according to the invention, which is simply connected with this tube to the outer stacking disk of the Stapelscheibenkühlers. In this case, of course, between the bypass channel and the outer stacking disk, a thermal separating element, such as insulation, or an air gap can be provided, which takes over the thermal insulation. In this case, the tube is particularly preferably designed as a double-walled tube, which already has an air gap jacket, which already effects thermal decoupling when connected to the outer stacking disc of the stacked disc radiator.

In an alternative embodiment of the solution according to the invention, a U-profile connected to the outer stacking disc is provided, which forms the bypass channel together with the outer stacking disc. Such a U-profile can be produced relatively cheaply a pipe, whereby the exhaust gas heat exchanger can be structurally simple in construction and manufactured inexpensively.

In a further advantageous embodiment of the solution according to the invention, the bypass channel and the stacked disc radiator are connected to the end in a diffuser or a flange, or in particular soldered thereto. In this way, a longitudinal-side version of both the bypass channel and the individual stacking discs of the stacked disc radiator can be accomplished comparatively easily, the entire stacked disc radiator with bypass duct and diffuser or flange, for example, prefabricated and then soldered in a brazing furnace.

Suitably, turbulence inserts, in particular rib or lattice structures, are arranged between the individual stack disks. By such a turbulence insert can be a heat transfer significantly improved turbulent Flow of the coolant can be generated, whereby the performance of the Abgaswärmeübertragers can be increased.

In a further advantageous embodiment of the solution according to the invention, each stacking disk of the stacked disk cooler is composed of a first and a second element. The first element may for example be U-shaped and have pronounced inner ribs, while the second element is trough-shaped with a tub bottom and tub edges. When mounted stacking disks while the inner ribs lie on the tub bottom and are in particular connected to these, for example soldered. Due to the multi-part structure of each stacking disk in particular their production is easier and thus cheaper possible.

The present invention is further based on the general idea of equipping an internal combustion engine with at least one such exhaust heat exchanger, which can be achieved faster at cold start their operating temperature, as well as, for example, the internal combustion engine downstream oxidation catalysts, whereby the nitrogen oxide emissions and fuel consumption can be reduced ,

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

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

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

Fig. 1

einen erfindungsgemäßen Abgaswärmeübertrager in einer Seitenansicht,

Fig. 2

eine Darstellung wie in Fig. 1, jedoch bei einer anderen Seitenansicht,

Fig. 3

unterschiedliche Darstellungen eines als doppelwandigen Rohrs ausgebildeten Bypasskanals,

Fig. 4

eine Seitenansicht auf einen erfindungsgemäßen Abgaswärmeübertrager mit dem gemäß der Fig. 3 gezeigten Bypasskanal,

Fig. 5

eine Schnittdarstellung durch den Abgaswärmeübertrager gemäß der Fig. 4 entlang der Schnittebene B-B,

Fig. 6

eine weitere mögliche Ausführungsform eines erfindungsgemäßen Bypasskanals, diesmal als U-Profil,

Fig. 7

eine Seitenansicht auf den erfindungsgemäßen Abgaswärmeübertrager mit demgemäß der Fig. 6 gezeigten Bypasskanal,

Fig. 8

eine Schnittdarstellung entlang der Schnittebene D-D aus Fig. 7,

Fig. 9

eine weiteren mögliche Ausführungsform eines erfindungsgemäßen Bypasskanals,

Fig. 10

eine Seitenansicht auf einen erfindungsgemäßen Abgaswärmetauscher mit demgemäß der Fig. 9 ausgebildeten Bypasskanal,

Fig. 11

eine Schnittdarstellung entlang der Schnittebene F-F aus Fig. 10,

Fig. 12

einen als Rohr ausgebildeten Bypasskanal,

Fig. 13

eine Seitenansicht auf einen erfindungsgemäßen Abgaswärmeübertrager mit demgemäß der Fig. 12 dargestellten Bypasskanal,

Fig. 14

eine Schnittdarstellung entlang der Schnittebene H-H aus Fig. 13,

Fig. 15

einen als Stapelscheibe ausgebildeten Bypasskanal,

Fig. 16

eine Seitenansicht auf einen erfindungsgemäßen Abgaswärmeübertrager mit demgemäß der Fig. 15 dargestellten Bypasskanal,

Fig. 17

eine Schnittdarstellung entlang der Schnittebene I-I aus Fig. 16.

Show, in each case schematically,

Fig. 1

an exhaust gas heat exchanger according to the invention in a side view,

Fig. 2

a representation like in Fig. 1 but with another side view,

Fig. 3

different representations of a bypass channel designed as a double-walled tube,

Fig. 4

a side view of an exhaust gas heat exchanger according to the invention with the according to the Fig. 3 shown bypass channel,

Fig. 5

a sectional view through the exhaust heat exchanger according to the Fig. 4 along the section plane BB,

Fig. 6

Another possible embodiment of a bypass channel according to the invention, this time as a U-profile,

Fig. 7

a side view of the exhaust gas heat exchanger according to the invention with accordingly the Fig. 6 shown bypass channel,

Fig. 8

a sectional view taken along the cutting plane DD Fig. 7 .

Fig. 9

another possible embodiment of a bypass channel according to the invention,

Fig. 10

a side view of an exhaust gas heat exchanger according to the invention with the accordingly Fig. 9 trained bypass channel,

Fig. 11

a sectional view along the cutting plane FF Fig. 10 .

Fig. 12

a trained as a tube bypass channel,

Fig. 13

a side view of an exhaust gas heat exchanger according to the invention with accordingly the Fig. 12 illustrated bypass channel,

Fig. 14

a sectional view taken along the cutting plane HH Fig. 13 .

Fig. 15

a bypass channel designed as a stacking disk,

Fig. 16

a side view of an exhaust gas heat exchanger according to the invention with accordingly the Fig. 15 illustrated bypass channel,

Fig. 17

a sectional view along the section plane II Fig. 16 ,

According to the Fig. 1, 2 . 4, 5 . 7, 8 . 9, 10 . 13, 14 and 16 and 17 , an exhaust gas heat exchanger 1 according to the invention has a heat exchanger region 2 and a bypass channel 3 bypassing this heat exchanger region 2. In addition, a bypass valve 4 is provided, which in the present case is designed as a flap valve, and which, according to position, divides the exhaust gas stream 5 between the heat exchanger region 2 and the bypass channel 3. According to the invention, it is now provided that in the heat exchanger region 2 a Stapelscheibenkühler 6 is arranged with a plurality of stacking disks 7, wherein the Bypass channel 3 attached to an outer stacking disk 7 'of the stacked disk cooler 6, in particular soldered.

The great advantage of the Abgaswärmeübertragers invention lies in the fact that the bypass channel 3 is not as in the prior art known and a tube bundle having exhaust gas heat exchanger enclosed by a housing and thus flows around coolant, but connected to one side of the stacked disc cooler 6 and is surrounded by the ambient air around the other three sides. This makes it possible to significantly shorten a cold start phase of an internal combustion engine 8, since the exhaust gas stream 5 flowing through the bypass channel 3 is not cooled by the stack disc radiator 6 and thereby both the internal combustion engine 8 and downstream oxidation catalysts can be brought to operating temperature more quickly. By quickly reaching the operating temperature can be in the internal combustion engine 8, both the consumption of fuel and the emission of nitrogen oxides reduced.

Looking at the exhaust gas heat exchanger 1, it can be seen that they have a lateral coolant inlet 9 and a lateral coolant outlet 10, via which the exhaust gas heat exchanger 1 is connected to a coolant circuit. Of course, the coolant inlet 9 or the coolant outlet 10 can also be arranged in reverse (countercurrent cooler).

Looking at the Fig. 1, 2 . 4 . 7 . 10 and 13 Further, it can be seen that both the bypass channel 3 and the stack disc cooler 6 are longitudinally connected in a diffuser 11 or generally to a flange 12 or connected, in particular soldered to this, are. A housing as previously known from the prior art exhaust gas heat exchanger, the exhaust gas heat exchanger 1 according to the invention does not have, thereby saving this component and thus not only the assembly costs, but also the storage and logistics and material costs can be reduced. Of particular advantage in the exhaust gas heat exchanger 1 according to the invention is moreover that the cooler designed as a stacked disc cooler 6 is much more powerful than previously used in this area tube bundle cooler.

Now consider the bypass channel 3 according to the FIG. 12 , it can be seen that this is formed by a simple tube 13. This tube 13 may be formed, for example, as a sheet metal tube or as an extruded profile and thereby manufactured comparatively inexpensive. In order to be able to reduce heat transfer between the stack disk cooler 6 and the bypass channel 3 as much as possible, it may be provided that the bypass channel 3 designed as a pipe 13 is connected via spacer elements 14 to the outer stacking disk 7 'of the stack disk cooler 6, so that between the bypass channel 3 and the outermost stacking disk 7 'of the stacked disk cooler 6, a heat-insulating air gap 15 remains. Of course, a full-surface soldering of the pipe 13 designed as a bypass channel 3 with the outermost stacking disk 7 'of the stacked disk cooler 6 is conceivable. It is also conceivable that the tube 13 as a double-walled tube 16 (see Fig. 3 ), whereby also a heat-insulating air gap 15 between an inner tube 17 and an outer tube 18 of the double-walled tube 16 remains.

Looking at the bypass channel 3 according to the Fig. 6 to 8 , it can be seen that this is formed in this case by a U-profile 19, which is connected to the outer stacking disk 7 '(see in particular the sectional view DD in Fig. 8 ). A similar U-profile 19 also has the exhaust gas heat exchanger 1 according to the Fig. 9 to 11 in which case the U-profile 19 still has small webs 20 at its U-legs, for example, to be able to form an improved soldering surface to the outer stacking disk 7 '.

Considering the sectional view through the exhaust gas heat exchanger 1 according to the invention according to the Fig. 5 . 8th . 11 and 14 It can thus be seen that each stacking disk 7, 7 'is composed of a first and a second element 21, 22. The first element 21 may for example be U-shaped and have pronounced inner ribs 23, while the second element 22 is trough-shaped, with a tub bottom 24 and tub edges 25, with mounted stacking disk 7, 7 'the inner ribs 23 abut the tub bottom 24 and in particular connected to this, for example soldered, are. As a result, a particularly rigid stacked disc cooler 6 can be achieved. In a stacked manner, the individual stacking disks 7, 7 'together exhaust channels 26 and coolant channels 27. In particular in the coolant channels 27 while turbulence inserts 28, in particular ribs or lattice structures may be arranged, which generate a turbulent flow and thus improve the heat transfer.

Now consider the bypass channel 3 according to the FIG. 15 , it can be seen that this is formed by a stacking disk 7,7 '. This stacking disk is preferably formed identically to the other stacking disks 7, whereby the variety of parts is reduced. According to the FIGS. 16 and 17 it can be seen that the bypass channel 3 is formed by the two uppermost stacking disks 7, 7 '. In contrast to the adjacent stacking disks 7 of the heat exchanger region 2, no turbulence inserts 28 are arranged in the bypass channel 3 formed by the stacking disks 7, 7 ', so that a throughflow without or with only a slight pressure drop is possible. The surrounding coolant channels 27 are not flowed through by coolant, whereby a heat-insulating air gap 15 remains here as well. This can be achieved by blocking an input of the respective coolant channels 27. The advantage of this solution is the reduced variety of parts. Due to the higher number of stacking disks 7, 7 ', their unit price can be reduced.

With the exhaust gas heat exchanger 1 according to the invention, for the first time, the long-term principle of equipping exhaust gas heat exchangers exclusively with tube bundle coolers has been deviated, specifically in such a way that now stacking disk coolers 6 are installed. At this Stapelscheibenkühler 6, the bypass channel 3 is connected to the outer (st) e stacking disk 7 ', which with the inventive exhaust gas heat exchanger 1, a bypass of the Stapelscheibenkühlers 6 and thus a faster heating of catalysts or an internal combustion engine 8 are possible. By compared to a tube bundle cooler significantly increased cooling capacity of the stacked disc cooler 6, it is also possible to make the exhaust gas heat exchanger 1 with the same dimensions more powerful or smaller but to make the same desired performance.

Claims (10)

Exhaust heat exchanger (1) with a heat transfer area (2), with a bypass channel (3) bypassing the heat exchanger region (2), - With a bypass valve (4) which, depending on the position, an exhaust gas stream (5) between the heat exchanger region (2) and the bypass channel (3), characterized, in that a stack disk cooler (6) with a plurality of stack disks (7, 7 ') is arranged in the heat exchanger region (2), - That the bypass channel (3) attached to an outer stacking disc (7 ') of the Stapelscheibenkühlers (6), in particular soldered. Exhaust heat exchanger according to claim 1,
characterized,
that the bypass channel (3) through a pipe (13) is formed. Exhaust heat exchanger according to claim 2,
characterized,
that the tube (13) is designed as a double-walled tube (16). Exhaust heat exchanger according to claim 1,
characterized,
in that a U-profile (19) connected to the outer stacking disk (7 ') is provided, which together form the bypass channel (3). Exhaust heat exchanger according to one of the preceding claims,
characterized,
that the bypass channel (3) is formed by at least one stacking wheel (7,7 '). Exhaust heat exchanger according to one of the preceding claims,
characterized,
that the bypass channel (3) and the stacked-plate cooler (6) integrated in the longitudinal end a diffuser (11) or connected to a flange (12), in particular soldered thereto, are. Exhaust heat exchanger according to one of the preceding claims,
characterized,
that turbulence inserts (28), in particular rib or lattice structures, are arranged between individual stacking disks (7, 7 '). Exhaust heat exchanger according to one of claims 4 to 7,
characterized,
in that each stacking disk (7, 7 ') is composed of a first and a second element (21, 22). Exhaust heat exchanger according to claim 8,
characterized, - That the first element (21) is U-shaped and has pronounced inner ribs (23), in that the second element (22) is formed in the shape of a trough with a trough bottom (24) and trough edges (25), the inner fins (23) resting on the trough bottom (24) when the stacking disk (7, 7 ') is mounted, and in particular connected thereto, for example, are soldered. Internal combustion engine (8) with at least one exhaust gas heat exchanger (1) according to one of the preceding claims.

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