WO2007045406A1

WO2007045406A1 - Heat exchanger

Info

Publication number: WO2007045406A1
Application number: PCT/EP2006/009924
Authority: WO
Inventors: Klaus Irmler; Ulrich Maucher; Jens Ruckwied
Original assignee: Behr Gmbh & Co. Kg
Priority date: 2005-10-20
Filing date: 2006-10-13
Publication date: 2007-04-26
Also published as: JP2009512832A; EP1941224A1; US20080251242A1

Abstract

The invention relates to a heat exchanger, especially for cooling exhaust gases. Said heat exchanger comprises at least one first flow channel (2) of a first medium, especially a gas, at least one second flow channel (3) of an at least second medium, especially a cooling medium, at least one first disk (4), at least one second disk (5), the first disk and the second disk being interconnected and defining the first flow channel of the first medium, at least one housing element (6), especially a first housing element (7) and a second housing element (8) defining, together with the first disk and the second disk, the second flow channel of the second medium, wherein the first housing element can be cooled by the second medium.

Description

heat exchangers

The present invention relates to heat exchangers, in particular for cooling exhaust gas, as well as a modular heat exchanger system.

Today's diesel engines are usually equipped with exhaust gas recirculation chillers to meet the ever-increasing requirements for exhaust gas pollution control. By cooling the exhaust gas and recirculating the cooled exhaust gas, the combustion temperature is lowered and leads to reduced NOX emissions.

DE 102 30 852 A1 discloses a heat exchanger with a first collecting tank and with a second collecting tank for a first medium, wherein the two collecting tanks each have a first media connection for the first medium and are communicatively connected to one another via at least one heat exchanger are and with a, the heat exchanger element receiving, inside a second medium leading housing having second media ports for the second medium. The housing accommodates in its interior at least one collection box, preferably both header tanks, at least partially with at least partially present existing distance to the housing inner wall. DE 100 61 949 A1 further discloses a heat exchanger which has a core region for carrying out a heat exchange between a first fluid and a second fluid, wherein the core region comprises a multiplicity of tubes which form first passages in the interior, through which the first fluid wherein the tubes are arranged to form a plurality of spaces between adjacent tubes through which the second medium flows, and a plurality of ribs each disposed in each space between adjacent tubes for dividing each space into a plurality of space portions which communicate with each other Openings are provided, which are provided in each rib; and a core housing accommodating the core portion and forming a second passage having the plurality of spaces, the two ends of each tube being separated from the inner wall surface of the core case at right angles to the longitudinal direction of the tubes, thereby providing predetermined clearances the inner wall surface of the core case, and the predetermined clearances are provided so as to communicate with each other along the entire surface area of the tubes in the lamination direction of the tube.

Exhaust coolers are typically laser welded or Ni-base brazed. and have ribs on the gas side. This ribs are usually cassetted in tubes and then soldered in a housing. Other known concepts provide for the Aufflötten of discs.

Most applications usually provide for the axial flow of a disk package through gas, the coolant is supplied from above via the cover plate or removed. However, this design has the problem that the housing can usually become very warm because the housing is not cooled. Proceeding from this, the object of the invention is to improve a heat exchanger, in particular for cooling exhaust gas, as well as a modular heat exchanger system.

The object of the invention is a heat exchanger according to claim 1, in particular for cooling exhaust gas, with at least a first flow channel of a first medium, in particular a gas, with at least a second flow channel of at least a second medium, in particular a cooling medium, with at least a first ticket Be, with at least one second disc, wherein the first disc and the second disc are connected to each other and form the first flow channel of the first medium, with at least one housing element, in particular a first housing member and a second housing member, which with the first disc and with form the second disc, the second flow channel of the second medium, wherein the first housing member is cooled by the second medium.

The first flow channel leads through inlet openings of the first medium, which in particular hot exhaust gas with a temperature of 200 ⁰ C to 800 °, by pairs of disks, each formed by two discs to an outlet opening. The second second flow channel of a second medium, in particular a cooling medium, in particular a liquid cooling medium such as water, leads through at least one inlet and at least one housing element, in particular a second housing element and through the opening due to a spacing of adjacent disc pairs and disc edge surfaces an outlet, in a second housing element. In each case, a first disc is connected to a second disc, in particular by material bond, such as soldering, welding, gluing. The first disks, the second disks and the housing element surround the second flow channels. By the second medium, in particular cooling medium such as liquid coolant, cooling water, air, refrigerant, in particular an air conditioner, the first housing element is cooled. The thermoelectric voltages are reduced. The heat exchanger, in particular the exhaust gas heat exchanger has a much greater durability. The housing member is made of a material manufacturer adjustable, which is not heat-resistant and especially at temperatures greater than 200 ° C, especially temperatures greater than 400 would be destroyed ⁰ C. In particular, the housing element made of plastic or aluminum can be produced inexpensively, whereby the manufacturing costs decrease significantly.

In an advantageous embodiment, the heat exchanger has a first housing element, which can be flowed around substantially completely by the second medium, in particular cooling medium, and which cools the housing element particularly advantageously, so that virtually no thermal stresses occur or are advantageously reduced and the fatigue strength increased considerably and the material costs are lowered particularly advantageous.

In an advantageous embodiment, the temperature of the first medium, in particular of the exhaust gas of an internal combustion engine, before it enters the heat exchanger is higher than the temperature of the second medium, in particular of the cooling medium, before it enters the heat exchanger. Despite a high temperature of the uncooled exhaust gas, hardly any thermal stresses occur on the housing element, which can be produced particularly advantageously from a cost-effective material.

In an advantageous embodiment, the first housing element made of a first material, in particular aluminum or plastic, and the second housing element of a different second material, in particular steel, is formed. In particularly advantageous manner, both housing elements are cooled particularly advantageously by the cooling medium. The first material, aluminum, plastic, etc. is particularly advantageous cost and leads advantageously to a weight saving and a smaller space requirement.

In an advantageous embodiment, the second housing element at least one housing opening, in particular a first housing opening for entry of the first medium in the first flow channel, in particular a second housing opening for a ride of the first medium from the first flow channel, in particular a third housing opening for a Admission of the second medium in the second flow channel and in particular a fourth housing opening for the outraging of the first medium from the second flow channel, on.

In an advantageous embodiment, the first housing element and the second housing element in at least one stacking direction of the first discs and the second discs are obvious. The discs and disc pairs are particularly advantageous mountable and manufacturable.

In an advantageous embodiment, the first housing element and the second housing element are cohesively, in particular by soldering, welding, gluing, etc., connected and connectable and / or positive, in particular by screws, clips, or by forming such as, folding, crimping, Beading, etc., connected or connectable.

In an advantageous embodiment, the first housing element and the second housing element with a sealing element, in particular an O-ring, four-channel ring, a film seal, etc., are particularly advantageously sealed against each other.

In an advantageous embodiment, the first disc and / or the second disc on characteristics, in particular turbulence generating elements between adjacent discs and / or disc pairs, whereby the Heat transfer Zweichen the first medium and the second medium is particularly advantageous improved.

In an advantageous embodiment, the first and / or the second discs at disc ends in each case at least one cup, whereby adjacent disc pairs are particularly advantageous verbundnen together and the first medium can flow particularly advantageous.

In an advantageous embodiment, the cups each have at least one cup opening, in particular for the passage of the first cooling medium on.

In an advantageous embodiment, each form a first disc, each with a second disc a disc pair and are particularly advantageous cohesively, in particular by soldering, welding, gluing, etc., connected to each other and form a disc pair.

In an advantageous embodiment, a plurality of pairs of discs are particularly advantageous stackable and connected to Napföffnungsrändern cohesively, in particular by soldering, welding, gluing, etc., with each other.

In an advantageous embodiment, the disk pairs form the first flow channels for the first medium, in particular for exhaust gas to be cooled, wherein the exhaust gas to be cooled flows particularly advantageously within a number of pairs of disks.

In an advantageous embodiment, two adjacent pairs of discs are spaced from each other. In this way, the second flow channels of the second medium, in particular cooling medium, are particularly advantageously formed between adjacent disk pairs. In an advantageous embodiment, the second flow channels of the second medium, in particular cooling medium, are formed between the first housing element and a disc pair edge surface. The disk pair edge surface is in particular the outer surface of the outer side of the interconnected pairs of disks of first and second disks.

In an advantageous embodiment, third flow channels of a third medium are formed in addition to the second flow channels, whereby the exhaust gas in two cooling stages successively is particularly advantageous coolable.

In an advantageous embodiment, the third flow channels of the third medium between the first housing element and the Scheibenpaarrand- surfaces are formed particularly advantageous.

In an advantageous embodiment, the third flow channels are separated from the second flow channels, in particular by at least one partition wall element. In this way, the at least two cooling circuits are separated particularly advantageous and the first housing element is cooled particularly advantageous, whereby thermoelectric voltages are particularly advantageous reduced and the fatigue strength of the heat exchanger particularly advantageous increases, and the cost Hestell especially reduced.

In an advantageous embodiment, wide flow channels can be flowed through with the second medium, in particular cooling medium, of a high-temperature cooling circuit and the third flow channels can be flowed through with a third medium, in particular cooling medium, of a low-temperature cooling circuit.

A heat exchanger has a first housing element, the integral component of at least one other component, in particular a water jacket, a cylinder head of an internal combustion engine, a water tank a coolant radiator, etc., is. The heat exchanger can be integrated in this way in an existing component, whereby in particular the space, especially in the front region of a vehicle is significantly reduced.

A heat exchanger, however, has a second housing element but no first housing element. The heat exchanger is used in particular for cooling exhaust gas, with at least one first flow channel of a first medium, in particular of a gas, with at least one second flow channel of an at least second medium, in particular a cooling medium, with at least one first disc, with at least one second disc, wherein the first disc and the second disc are connected to each other and form the first flow channel of the first medium, with at least one second housing element.

A modular heat exchanger system has at least one heat exchanger, in particular for cooling exhaust gas, with at least one first flow channel of a first medium, in particular of a gas, with at least one second flow channel of an at least second medium, in particular a cooling medium, with at least one first sheet, with at least one second disc, wherein the first disc and the second disc are connected to each other and form the first flow channel of the first medium, with at least one housing element, in particular a first housing element and a second housing element, which with the first disc and the second disc form the second flow channel of the second medium, wherein the first housing member is cooled by the second medium.

In a further advantageous embodiment, the cooler consists of a

Disc package. The disk package consists of disk pairs which form a flow channel for a first medium and turbulence generating

Structures, in particular turbulence inserts have. These can be be formed by indentations in the discs or preferably by a soldered turbulence plate. The spaces between two slices form channels for a second medium. In each case two adjacent pairs of disks are connected at both ends to the adjacent pairs of disks in fluid communication via lateral openings which can be arranged in a dome or wells formed from one disk or from both disks, in order to bridge the gap between the pairs of disks. The pairs of discs are in particular formed from two identical discs. The spaces between the panes can each be supported by knobs, dimples or inserted elements, such as sheets, ribs, supporting elements against each other. The supporting elements can be welded together, soldered or glued or held by positive locking. Nubs or dimples are embossed in the disc material. They can also be pronounced as elongated beads for improving the flow distribution of the second medium in the flow channel.

In a further embodiment, the first medium will be a medium to be cooled, in particular a hot medium, usually a hot gas such as exhaust gas or compressed charge air and the second medium is a liquid cooling medium, such as coolant of an internal combustion engine or in future applications refrigerant of a refrigeration cycle. The coolant can be guided in parallel or counter to the main flow direction of the first medium (direct current or countercurrent). The concept is particularly suitable for the thermodynamically preferable countercurrent connection, as it is characterized by a particularly low boiler risk in the coolant, because by proper steering of the coolant dead water areas can be largely prevented.

In a further embodiment, the flow channel for the second medium may be divided into two sections, which are mixed with coolant from different Cooling circuits are supplied, in particular a circuit with warmer coolant at the inlet end of the first medium and a Niedertem- temperature cooling circuit at the outlet end of the first medium to increase the cooling capacity. The separation of the circuits can be achieved, for example, by means of a transverse bead embossed in the disks, wherein the laterally free channel is blocked by a component that is form-fitting to the disk pair (a type of rake) with sufficient tightness. Such rakes can also be carried out so that no transverse beads are required in the discs, but the channel is blocked by at least two rakes inserted into the disc bundle on the opposite sides. However, these rakes can in turn be positioned by beads or nubs, in particular during a soldering process or if there is no firm connection with the disk bundle

In a further embodiment, the channel for the second medium to the outside by a housing shell or he formed by a coolant-flowed cavity in another component, for example in the water jacket or cylinder head of the engine block, in the water tank of a coolant radiator (Intank) or in a Coolant-flowed large housing, in which several heat exchangers are integrated and connected to form a module.

In a further advantageous embodiment of the heat exchanger with its own housing shell, an at least two-part housing jacket is used which opens substantially in the stacking direction of the disk bundle. The essential components of the housing shell form, for example, a cover or cover plate closing off the disk bundle at the top, as well as a trough into which the disk bundle is inserted. Lid and tub are circumferentially connected to each other in a particularly favorable design, in particular also soldered. The connections for the second medium are at the opposite ends of the housing and can be arranged in any arrangement in any of the parts of the housing. To integrate several cooling circuits further connections are provided in the radiator center. The connections for the first medium can either be on the same side of the heat exchanger, for example, both in the lid or both in the housing pan. Furthermore, a diagonal flow is possible in which either the inlet or the outlet in the lid and the other connection is located in the housing pan. Finally, the leadership of the first medium in the U-flow is possible. Not all disk pairs are in flow connection at the inlet for the first medium, but this connection is prevented at a point between two specific pairs of disks by the side connecting openings are either not executed between these pairs or an additional sheet is inserted, which is the connection locked and decoupled the pair of discs lying on the entry from the underlying disc pairs. The first medium flows through the cooler in the interconnected under the entrance to the interruption slices in the heat exchanger longitudinal direction. At the other end, all the pairs of discs are connected to each other and the first medium flows into the pair of discs decoupled at the inlet end and flows back to the inlet end, where it leaves the heat exchanger on the side opposite the inlet through an outlet.

The housing must withstand the pressure of the second medium. In the direction perpendicular to the stacking direction of the heat exchanger, the housing is not soldered to the disc bundle. It may be useful to increase the pressure stability of this page by embossed beads in the housing.

In a further advantageous embodiment, it is particularly advantageously prevented that the disks move transversely to the stacking direction during the soldering process. The discs may be made in places form-fitting to the housing contour. Furthermore, it may be advantageous if, in a first joining step, respective pairs of discs are prefabricated with a turbulence insert to channels for the first medium. These pairs of disks can be connected to one another by means of a form-locking design with or without pressing, by a clamping or crimp connection, which is essentially a seam connection, by means of spot welds or adhesive dots or the like. By this procedure, the Kassettierprozess (stacking of items, insbesondre the discs) can be considerably simplified and the process reliability of the entire joining process can be increased.

Embodiments without their own housing jacket of the heat exchanger are also particularly advantageous. Then, the disc bundle is closed at the top by a cover plate, in which the inlet and outlet for the first medium is integrated. Below is usually a base plate. The attachment to the installation is carried out by a dense joint between the cover plate and the coolant flowing through the cavity-forming member, for example via a screw, crimp or flare, clamping connection, the seal is usually ment by a sealing element, for example an O-ring , This type of connection can also be used for the execution of a separate radiator shell, for example, by a cover plate made of a steel or aluminum material in the manner mentioned is connected to a water-bearing plastic housing. For connection, for example, a flare connection or a screw connection with injection thread sleeves in a plastic component and oblong holes in the cover plate can be used. Furthermore, the screw connection can be made through through holes in the housing and screwing in the cover plate (threads in passages, self-tapping screws in a smooth passage, threaded bushing). In a further advantageous embodiment, the flow channel for the second medium (housing or cavity in another component) is advantageously designed so that it widens in the region in which the channel cross-section is severely limited by the dome at the disk ends, and then narrows again toward the center of the heat exchanger, so that the second medium is forced into the channels between the pairs of discs. Thus, the distribution of the second medium can be significantly improved. A likewise very favorable possibility to achieve the best possible distribution of the second medium is the funnel-shaped design of the transition of the disks from the domes to the channel for the 1st medium. This also forces the second medium into the channels between the pairs of discs.

In a further advantageous embodiment, an uncooled bypass passage can be provided in the cooler, for example in the form of one or more pairs of disks. In order to achieve the substantially uncooled passage of the first medium (in particular recirculated exhaust gas of an internal combustion engine), an air gap insulation of the bypass channel is preferably used. Exemplary embodiments for air-gap-insulated bypass pipes: outer shell made of half-shells soldered, internally inserted a pipe with supporting knobs

- Soldered outer and inner shell of half shells

- On the lid or cover another soldered sheet, which forms a channel with the cover / cover, which is used as a bypass channel (not air gap isolated).

- On the side facing the disc bundle side of the cover plate cover another sheet is soldered and forms an additional gas channel (not air gap isolated)

- On the cover / cover a bypass tube, which may be one or two parts soldered, which is avoided by beads or knobs in the bypass channel and / or in the cover / cover a flat support - At gas inlet or outlet in the housing pan, the bypass can be formed in the same ways with additional sheets or tubes as described for the cover / cover plate.

- if the gas enters or exits the cover / cover plate and the other gas connection in the housing pan, the bypass can be applied to one of the two parts and the bypass can include the transverse connection between the pairs of discs

- In the U-flow, a bypass solution can be provided by the fact that the decoupling between the disc pairs on the inlet side and on the opposite side is performed switchable, for example by a rotary valve, which releases the direct path from the inlet to the outlet in the bypass case and normal Cooler operation interrupts the passage, so that the radiator is flowed through in the U-flow.

In a further advantageous embodiment, a conventional, external valve is used as a bypass valve with separate supply lines to the bypass and to the heat-transferring flow channels. But it can also be used in the inlet nozzle or outlet nozzle integrated valves or valves. These can in particular also be designed as a flap or rotary slide. Particularly advantageous is the design of the bypass valve as a combination valve, in which in addition to the circuit between the bypass and normal radiator operation both paths can be completely locked and thus the amount of recirculated exhaust gas can be controlled.

In a further advantageous embodiment, in particular in the housing-less design, a heat exchanger in the cross-flow between the first and second medium can be used. Such heat exchangers could preferably be used in the cooling module of a motor vehicle. In this case, the medium to be cooled would be passed through the heat exchanger as the first medium, and cooling air would be used as the second medium. Such a heat exchanger can with the cover plate and the bottom plate in the frame However, it can also have its own frame, on the one hand includes cover plate and bottom plate with but also also creates a connection between the cover plate and bottom plate, thus ensuring a stiffening of the heat exchanger. The connection between cover and bottom plate can be represented either by additional components which are connected to cover and bottom plate or by the clever design of the cover and bottom plate, for example as against each other opening, U-shaped components, which together form the frame. form. This frame can also be in connection with the individual pairs of discs. As a result, in particular the vibration resistance of the component is increased. The connection can be made by positive locking, but in particular also be represented by a fixed solder joint. The attachment of the heat exchanger is then carried out on the frame and / or via the connections for the first medium. Instead of the arrangement of the heat exchanger in a cooling module, this can also be mounted in the chassis so in particular on the frame of a motor vehicle, in exceptional cases also motor-fixed. Preferably, such a component can be used as a direct exhaust gas cooler. But there are also applications as intercooler, coolant radiator, oil cooler, condenser, etc. makes sense.

Further advantageous embodiments will be apparent from the dependent claims and from the drawing.

Embodiments are illustrated in the drawings and will be explained in more detail below. Show it

1 is an exploded view of a heat exchanger,

2 is an isometric view of the heat exchanger, 3 shows a section AA through the heat exchanger,

4 shows a section B-B through the heat exchanger,

5 is an exploded view of another heat exchanger,

6a is a plan view of another embodiment of the heat exchanger with a formation in the inlet and outlet region of the housing element,

6b is an isometric view of a further exemplary embodiment of the heat exchanger with a formation in the inlet and outlet region of the housing element,

7 shows a further embodiment of the heat exchanger as a U-flow cooler,

8 shows a further exemplary embodiment of the heat exchanger as a double heat exchanger,

9 shows a further embodiment of the heat exchanger with two-stage cooling,

10 shows a further embodiment of the heat exchanger as a double heat exchanger with, wherein the first part of the heat exchanger is cooled with a high-temperature circuit and the second part of the heat exchanger is cooled with a low-temperature circuit,

11 shows another embodiment of a heat exchanger in cross-flow configuration, 12 shows a further embodiment of a heat exchanger with an integrated bypass channel and a rotary valve for controlling the flow of the bypass channel and / or the heat exchanger section,

Fig. 13 is another embodiment of a heat exchanger with an integrated bypass channel of the air gap insulated.

Fig. 1 shows an exploded view of a heat exchanger. The heat exchanger 1 has a first housing element 6, 7 and a second housing element 8. The housing member 6,7 receives first discs 4 and second discs 5 in itself. The first disks 4 and the second disks 5 are arranged substantially parallel to one another and stackable. A first disk 4 forms a disk pair 22 with a second disk 5. The first and second disks are connected to one another in a material-locking manner, in particular by soldering, welding or gluing. Likewise, adjacent pairs of disks 22, in particular on cups 20 at both disk ends 19 of the disks 4, 5 or the pairs of disks 22, are connected to one another in a material-locking manner, in particular by soldering, welding or gluing. The disks 4, 5 and the disk pairs have cup openings 21. The first housing element 6,7 is integrally connected and / or positively connected to the second housing element. The second housing element has a first housing opening 10 for the inlet 11 of the first medium. Through the first flow channel 2, the first medium, in particular the hot exhaust gas, flows into and through the cup pairs 22 through the cup openings 21, flows through the pair of discs in the flow channel 2 formed in the interior and flows out of the latter through a second housing opening 12 of the housing element 8 exiting the exit 13. The disk pairs are stackable in the stacking direction S. The housing element 8 has a third housing opening 14, which passes through an inlet 15 cooling medium, in particular liquid coolant, cooling water, gas or refrigerant, in particular an air conditioner in the first housing element 6, 7 and this Kühlt, so that there are essentially no thermal stresses. The second cooling medium flows around the outer sides of the disks 4, 5 and the pairs of disks 22 as well as the disk pair edge surfaces 24. It flows through openings which are formed by the spaced pairs of disks, whereby a heat exchange between the exhaust gas to be cooled takes place. Second flow channels 3 of the cooling medium are also formed between the first housing element 6, 7 and the disc pair edge surfaces 24, as a result of which the housing element 6, 7 is essentially cooled. The cooling medium leaves via an outlet 17 a fourth housing opening 16 of the housing element 8. The heat exchanger 1 can be installed as a module in a modular system. The heat exchanger can be integrated in a cooling module. A cooling module comprises in particular a plurality of heat exchangers, in particular coolant radiator, oil cooler, intercooler, exhaust gas cooler, heat exchanger of an air conditioner.

Fig. 2 shows an isometric view of the heat exchanger. Identical features are provided with the same reference numerals as in FIG. 1.

The housing member 6,7 takes in its interior the discs 4,5 and the

Slice pairs 22 on. The first housing element 6,7 is connected to the second

Housing element 8 cohesively by soldering, welding, gluing, etc. and / or positively connected by crimping, Wellschlitzbördeln, crimping, folding, clips, etc. In an embodiment, not shown, both

Housing elements sealed by a sealing element, in particular an O-ring, etc. with respect to each other.

3 shows a section AA through the cup openings 21 of the heat exchanger. Identical features are provided with the same features as in the previous figures. Fig. 4 shows a section BB through the heat exchanger. Identical features are provided with the same features as in the previous figures. Adjacent pairs of disks are spaced apart by forms, in particular turbulence inserts or turbulence-generating elements. Especially. In particular, the heat transfer between the first medium and the second medium is improved. Variants, in particular turbulence inserts or turbulence-generating elements, 18 are also arranged within the pairs of disks and in particular are connected to the disks 4, 5 by soldering, welding, gluing and / or formed from them by forming.

The pairs of disks may be laterally in contact with the housing element 6, as well as have a defined distance from each other. Section B-B shows pair of discs in contact with housing element.

Fig. 5 shows an exploded view of another heat exchanger. Identical features are provided with the same features as in the previous figures. The heat exchanger 25 has no first housing element. 8. The heat exchanger 25 can be installed as a module in a modular system. In particular, it is arranged adjacent to a fan 26 and durchströms with air L. The heat exchanger can be integrated in a cooling module. A cooling module comprises in particular a plurality of heat exchangers, in particular coolant radiator, oil cooler, intercooler, exhaust gas cooler, heat exchanger of an air conditioner.

FIG. 6a shows a plan view and FIG. 6b shows an isometric view of a further exemplary embodiment heat exchanger 60 with a shaping in the inlet and outlet area of the housing element. Identical features are provided with the same reference numerals as in the previous figures. In the heat exchanger 60, the cooling medium 17 in the inlet region is distributed optimally over the entire width of the disk pairs in the housing element 6, 7 by a formation 61, which is designed in particular as a bulge. Thus, the inlet area of the first medium is cooled at its entire circumference.

Fig. 7 shows a further embodiment of the heat exchanger as a U-flow cooler. Identical features are provided with the same reference numerals as in the previous figures.

In a sectional view of the heat exchanger 70 is shown. The heat exchanger is designed as a so-called U-flow design. In this case, the cooling medium 15,17 is passed axially, while the first medium flows in a U-shape through the heat exchanger. This is realized in that between see two pairs of discs, a separating plate 71 is inserted. This has no opening in the region of the outlet of the first medium (cup region). While on the opposite side there is a suitable opening in the cup area, so that the first medium can flow from the upper half of the cooler into the lower half. In this case, the position of the separating plate 71 is arranged in other embodiments not shown above or below the center, so that either above the dividing plates, the same number of disc pairs are present or they are unevenly distributed.

8 shows a further embodiment of the heat exchanger as a double heat exchanger. Identical features are provided with the same reference numerals as in the previous figures.

It shows a section of the heat exchanger 80 with the above-mentioned separating plate 81 is completely closed. This can be very easy

Heat exchanger can be realized, which is designed as a double heat exchanger is. In the double heat exchanger 80, two media, a first medium and a third medium, in particular two different media, are cooled. For this purpose, there are openings 82, 83, 84 and 85 for the outlet of the first medium and of the third medium both at the lower end and at the upper end of the disk stack with the disks 4, 5. The flow direction of the two media takes place in cocurrent or in countercurrent.

Reference numeral 86 represents the exit for the third medium. Reference numeral 87 represents the entry for the third medium. In another embodiment, the entrance 87 and the exit 86 are interchanged.

Fig. 9 shows a further embodiment of the heat exchanger with two-stage cooling. Identical features are provided with the same reference numerals as in the previous figures.

The heat exchanger 90 has two cooling media circuits. The first cooling circuit is a high-temperature circuit. The second cycle is a low temperature cycle. The coolant in Hochtemperturkreislauf has a higher temperature than the coolant in the low-temperature circuit. This makes it possible to realize a high and low temperature coolant circuit in a heat exchanger. The separating plate 91 is designed as a rake. The separating plate 91 is pushed onto the pairs of discs, in particular orthogonal to the disc longitudinal axis SLA. Furthermore, the housing element has four openings 92, 93, 94 and 95 for the exit and / or entry of the two cooling media.

Reference numeral 97 represents the inlet for the second cooling medium, in particular the low-temperature circuit. Reference numeral 96 represents the outlet for the second cooling medium. In another embodiment, the inlet 97 and the outlet 96 are reversed. In another embodiment, the heat exchanger 90 as a U-flow cooler, wherein the first and the second cooling medium performs a U-flow, formed, analogous to the embodiments in Figure 7 and 8.

Fig. 10 shows another embodiment of the heat exchanger as a double heat exchanger. Identical features are provided with the same reference numerals.

The heat exchanger 100 has a first partial heat exchanger 101, which is cooled by a high-temperature circuit, and a second partial heat exchanger 102, which is cooled by a low-temperature circuit. In another embodiment, high-temperature circuit and low-temperature circuit are reversed.

Into the inlet 103, the second cooling medium, in particular the low-temperature circuit, enters partial heat exchanger 102, flows through it and leaves the partial heat exchanger through outlet 104. Outlet 104 and inlet 103 are interchanged in another exemplary embodiment.

The third medium enters the partial heat exchanger 102 via the media inlet 105, flows through it and leaves it via the media outlet 106. In another embodiment, the media outlet 106 and the media inlet 107 are interchanged.

The separating plate 107 separates the first partial heat exchanger 102 and the second partial heat exchanger 103, in particular in terms of flow.

11 illustrates another embodiment of the heat exchanger shown in FIG. 5 in cross-flow configuration. The heat exchanger 110 has no housing and is designed in particular as a cross-flow heat exchanger. In doing so, the currents between which a heat transfer occurs at least in some areas. In this case, there is a cooling rib between the disk pairs 4, 5, which form the flow channels for the first medium. This is firmly connected to the disk pairs 4,5, for example, soldered, glued, mechanically joined, etc., so that a sufficient heat conduction between the pairs of disks and the rib 4,5 is ensured. The rib 111, in particular the corrugated fin, is thereby flowed through by a cooling medium, for example air. The air is moved by means of a cooling medium conveyor L _1, for example, a fan L. In another embodiment, no rib is provided. In this case, a turbulence generating structure is impressed into the disks, which improves the heat transfer. In another embodiment, the Kreuzströmer execution executed with a housing. This results in the advantage that this heat transfer medium not only in the front module of the vehicle, ie in the front of the vehicle, in which the flow is made by the wind, but regardless of which can be attached to a suitable location in the vehicle with its own cooling media promotion.

12 shows a further exemplary embodiment of a heat exchanger 120 with an integrated bypass channel and a rotary valve for controlling the flow of the bypass channel 121 and / or the heat exchanger section 122. Identical features are provided with the same reference numerals as in the previous figures.

The rotary valve 123 assumes a bypass position and / or a radiator throughflow position. The rotary valve 123 has at least one recess. In the bypass position, the bypass 121 is flowed through. In the cooling position, the heat exchanger section 122 is flowed through. In another embodiment, bypass 121 and heat exchanger section are reversed.

The rotary valve 123 can also assume a position in which both the bypass 121 and the heat exchanger section are flowed through. The rotary valve makes a rotation by an angle of rotation, in particular of 90 °, in order to move from the bypass position into the heat exchanger throughflow position.

FIG. 13 shows a further exemplary embodiment of a heat exchanger with an integrated bypass channel 131, which is designed to be air-gap-insulated. Identical features are provided with the same reference numerals.

The bypass channel 131 serves to bypass medium, so that the medium does not flow through the heat exchanger. The insulation, in particular air gap insulation, serves to prevent or reduce the heat transfer between the bypass channel 131 and the heat exchanger.

In other versions of the Flg. 1 to 13, turbulence-generating elements or the turbulence inserts are designed as rib ribs.

Turbulence inlays with ribbed ribs have a relatively low tendency to accumulate deposits, in comparison to other inlays, in comparison with other liners, with smaller passage cross sections. Basically, it was to be feared that turbulence inserts with rib ribs would increasingly lead to the blocking of individual passageways due to the delicate structure of the rib ribs. However, this is the case to a surprisingly small extent, in particular if the webs of the rib ribs are relatively short. A possible explanation for this could be that through the A turbulent flow of the exhaust gas over large parts of the ribbed insert is a deposit of particles is reduced, whereas at longer, uniform channels ordered flows are formed, which favor the deposition of particles near the wall due to the very low flow velocity there.

In a preferred embodiment, the webs of the rib ribs have a length which is not more than about 10 mm, preferably not more than about 5 mm and particularly preferably not more than about 3 mm. Depending on the given installation space and internal combustion engine, there may be specific requirements for the pressure drop at the exhaust gas heat exchanger. Depending on these requirements, one of the aforementioned length ranges may be preferred.

Furthermore, a density of the rib ribs transversely to the direction of the exhaust gas flow is preferably between about 20 rib ribs / dm and about 50 rib ribs / dm, preferably between about 25 rib ribs / dm and 45 rib ribs / dm. These Stegripendichten have been found in experiments to be particularly suitable. In particular, the rib ribs particularly advantageously represent a good compromise between blocking risk and cooling performance.

With regard to a height of the rib ribs, it should be taken into account that at relatively high altitudes only relatively small primary surfaces, ie surfaces cooled by coolant, are available, via which the entire heat must be released into the coolant. With relatively small primary surfaces, the boil risk increases in the case of a liquid coolant. In addition, the efficiency of the deposits decreases with increasing height of the rib ribs. A preferred height of the insert or Stegrippe is therefore between about 3.5mm and about 10mm, more preferably between about 4mm and about 8mm and more preferably between about 4.5mm and about 6mm. In a preferred development of the device according to the invention, provision may be made for an oxidation catalytic converter to be arranged upstream of the plurality of flow channels. By such a catalyst can be generally reduce the particle sizes, particle densities and the proportions of hydrocarbons in the exhaust gas by oxidation. It may be additionally or alternatively provided that the deposits themselves are provided with a coating for the catalytic oxidation of the exhaust gas. In particular, in conjunction with oxidized catalytic agents, the useful usable density of the rib ribs transverse to the exhaust gas flow direction can be more than about 50 ribs / dm, in particular about 75 rib ribs / dm. As a result, a particularly large heat exchanger capacity would be achieved with a given installation space without the long-term danger of deposits being blocked.

In a particularly preferred embodiment, the rib ribs are helically toothed. Helical ribs are according to experimental findings particularly suitable to ensure a long-term stability of the exhaust gas heat exchanger against deposits. In this case, in a preferred embodiment, the angle between the web walls and a main direction of the rib ribs between about 1 ° and about 45 °. In a particularly preferred embodiment, the angle between about 5 ° and about 25 °, where it may be in an alternative preferred embodiment, between about 25 ° and about 45 °. The first-mentioned value range 5 ° to 25 ° is particularly well suited for typical applications which are sensitive to high pressure loss, whereby the second range of values is suitable for achieving an optimized power density, in particular for less pressure loss sensitive applications.

In general, when optimizing an insert with helical ribs, a correlation between the angle of the walls and a

Determine longitudinal division of the rib. In particular, optimal Designs at small angles larger pitches I have as optimized versions with large angles. Particularly with small angles of attack, designs with moderate pressure loss can result. Particularly with large angles of attack, designs with optimized power density can result. In particular, with small angles of attack, the longitudinal pitch can be greater, with large angles of attack, the longitudinal pitch can be smaller in particular to obtain optimized versions.

In a preferred embodiment, the device is designed as a stacked plate heat exchanger. Both in terms of the width of a flow channel as well as in terms of cost-effective production and combinability of a heat exchanger housing with ribbed ribbed inserts, this embodiment is particularly suitable. Alternatively, the device can also be designed as a tube bundle heat exchanger or as another known per se heat exchanger.

In general, the insert is preferably made of a stainless steel, in particular an austenitic steel, in order to prevent corrosion caused by the aggressive exhaust gas.

In a further advantageous embodiment, aluminum materials can be used, in which case a suitable corrosion protection can be provided in a particularly advantageous manner, such as in particular an alloy and / or a coating.

In an advantageous development, the insert is formed of aluminum. The insert made of aluminum has a particularly low weight. Particularly advantageously, the insert made of aluminum can be formed by means of an alloy or coating for corrosion protection. Depending on the flow parameters, in particular the Reynolds number, the length of the inlet region of the flow channels, in particular tubes and / or stacking disk pairs, l / s about 2.5 to 5 and the length of the rib ribs must be selected below this limit. S denotes the mean passage width between two webs and is thus b / 2-t, where t denotes the sheet thickness. The result is a required ratio l / s <4, in particular l / s <2. For high blocking risk by critical exhaust gas composition l / s <1, 5, in particular l / s <1 to choose.

By an inclination of the webs occurs on the twist side, a higher flow velocity on the wall, which counteracts the soot deposition. Another decisive advantage of helical ribbed ribs is that in cases where a low density of the rib ribs in the transverse direction of flow is required to prevent blocking, in particular in the case of unfavorable exhaust gas composition, a sufficient cooling capacity can be ensured despite the small rib surface.

The stacked plate heat exchanger according to the invention comprises an outer housing with a cover, wherein an inlet and an outlet are provided for the exhaust gas and an inlet and an outlet for a liquid coolant. Within the housing, a plurality of disc elements are provided, wherein each of the disc elements is composed of an upper half and a lower half. By means of turned-on collar, the disc elements are welded to one another and to the housing so that the coolant flows in each case between the two halves of a disc element from the inlet to the outlet. Between two disc elements in each case a not shown inlay with rib ribs is arranged, wherein the intermediate space between two disc elements in each case forms a flow channel for the exhaust gas. The deposits are not shown for reasons of clarity. The inserts are made of stainless steel. To improve the thermal contact between the inserts and the disc elements or the housing, the inserts can be welded or soldered flat with said elements.

In a further embodiment, the turbulence insert consists of a thin sheet metal material into which parallel rib ribs are introduced by means of forming measures. Each of the rib ribs comprises a series of webs successively arranged in the exhaust gas flow direction. In each case two webs, which follow each other in the exhaust gas flow direction, are arranged offset from one another by half a web width transversely to the exhaust gas flow direction, so that after each web a cutting edge adjoins a subsequent web. In the present example, the walls are aligned parallel to the flow direction of the exhaust gas and form with an axis B of the rib ribs and the main flow direction of the exhaust gas A at an angle of 0 °. Such a ribbed insert is referred to as a straight-toothed rib.

In the first embodiment, the length I of a ridge is about 4mm. The width b of a single rib is defined as the width of the repeat unit of the periodic structure transverse to the main flow direction of the exhaust gas. The Stegrippendichte 2 / b is in the present example about 40 Stegrippen / dm. The width b of a Stegrippe is thus about 5mm

The height h of the rib ribs corresponds to the distance between two adjacent disc elements of the heat exchanger and is presently about 5 mm.

In a further embodiment of the ribbed ribbed insert, the lateral walls of the individual ribs are not aligned parallel to the main direction B of the rib ribs. Rather, each of the walls of the webs with the main direction B of the rib ribs includes an angle W of about 30 °. The other dimensions of the helical ribbed insert correspond to the dimensions of the straight-serrated ribbed rib. Suitable longitudinal pitch I for corresponding angles of the walls W provide suitable embodiments at 10 ° with longitudinal pitches I <ca.i Omm, at 20 ° with I <about 6mm, at 30 ° with kca. 4mm and at 45 ° with l <about 2mm. The minimum longitudinal pitch I is approximately 1 mm at all angles. The permissible channel extension l / s is approximately within the same limit as for a straight toothed rib, where s denotes the web spacing transverse to the main flow direction B. As a rule, longitudinal divisions I <1 mm are difficult to produce for manufacturing reasons.

The features of the various embodiments can be combined with each other. The invention can also be used for other than the areas shown.

Claims

Patent claims

1. Heat exchanger, in particular for cooling exhaust gas, comprising at least a first flow channel (2) of a first medium, in particular a gas, at least one second flow channel (3) of an at least second medium, in particular a cooling medium, at least one first disc (4), at least one second disc (5), wherein the first disc (4) and the second disc (5) are interconnected and form the first flow channel (2) of the first medium, with at least one housing element (6), in particular a first Housing element (7) and a second housing element (8), which with the first disc (4) and with the second disc (5) form the second flow channel (3) of the second medium, characterized in that the first housing element (6, 7 ) is cooled by the second medium.

2. Heat exchanger according to claim 1, characterized in that the first housing element (6, 7) is substantially completely flowed around by the second medium, in particular cooling medium.

3. Heat exchanger according to claim 1 or 2, characterized in that the temperature of the first medium, in particular the Ab- gases of an internal combustion engine, before entering the heat exchanger is higher than the temperature of the second medium, in particular the cooling medium, before entering the heat exchanger.

4. Heat exchanger according to one of the preceding claims, characterized in that the first housing element (6, 7) made of a first material, in particular aluminum or plastic, and the second housing element (8) made of another second material, in particular steel, are formed.

5. Heat exchanger according to one of the preceding claims, characterized in that the second housing element (8) at least one housing opening, in particular a first housing opening (10) for an inlet (11) of the first medium in the first flow channel (2), in particular a second Housing opening (12) for a ride

(13) of the first medium from the first flow channel (2), in particular a third housing opening (14) for an inlet (15) of the second medium in the second flow channel (3) and in particular a fourth housing opening (16) for a ride of the first Mediums from the second flow channel (3).

6. Heat exchanger according to one of the preceding claims, characterized in that the first housing element (6, 7) and the second housing element (8) in at least one stacking direction Sder first discs (4) and the second discs (5) are apparent.

7. Heat exchanger according to one of the preceding claims, characterized in that the first housing element (6, 7) and the second housing element (8) cohesively, in particular by soldering, welding, gluing, etc., connected and / or positively, in particular by screws, clips, or by forming such as, folding, crimping, flanging, etc., are connected.

8. Heat exchanger according to one of the preceding claims, characterized in that the first housing element (6, 7) and the second housing element (8) with a sealing element, in particular an O-ring, Vierkantring, a film seal, etc., are sealed against each other.

9. Heat exchanger according to one of the preceding claims, characterized in that the first disc (4) and / or the second disc (5) have embossments (18), in particular turbulence-generating elements (18).

10. Heat exchanger according to one of the preceding claims, characterized in that the first discs (4) and / or the second discs (5) at the disc ends (19) each have at least one cup (20).

11. Heat exchanger according to claim 10, characterized in that the

Cups (20) each have at least one cup opening (21), in particular for the passage of the first cooling medium having.

12. Heat exchanger according to one of the preceding claims, characterized in that in each case a first disc (4) each having a second disc (5) form a disc pair (22) and are materially connected, in particular by soldering, welding, gluing, etc., together.

13. Heat exchanger according to claim 12, characterized in that a plurality of disk pairs stackable on one another and at Napföffnung cohesively, in particular by soldering, welding, gluing, etc., are interconnected.

14. Heat exchanger according to claim 12 or 13, characterized in that the pairs of discs (22) form the first flow channels (2) for the first medium, in particular for exhaust gas to be cooled.

15. Heat exchanger according to one of claims 12 to 14, characterized in that adjacent pairs of disks (22) are arranged spaced from each other and in this way the second flow channels (3) of the second medium, in particular cooling medium, are formed.

16. Heat exchanger according to one of the preceding claims, characterized in that at least between the first housing element (6, 7) and a disc pair edge surface (24), the second flow channels (3) of the second medium, in particular cooling medium, are formed.

17. Heat exchanger according to one of the preceding claims, characterized in that in addition to the second flow channels (3) third flow channels of a third medium are formed.

18. Heat exchanger according to claim 17, characterized in that the third flow channels of the third medium between the first

Housing element (6, 7) and the disc pair edge surfaces (24) are formed

19. Heat exchanger according to claim 17 or 18, characterized in that the third flow channels of the second flow channels (3), in particular by at least one partition element, are separated.

20. Heat exchanger according to one of claims 17 to 19, character- ized in that the second flow channels (3) with the second

Medium, in particular cooling medium, a high-temperature cooling circuit runaway and the third flow channels with a third medium, in particular cooling medium, a Niedertemperaturkühlkreis- are flowable beströmbar.

21. Heat exchanger according to one of the preceding claims, characterized in that the first housing element (6, 7) integral part of at least one other component, in particular a water jacket, a cylinder head of an internal combustion engine, a water tank of a coolant radiator, etc., is.

22. Heat exchanger according to one of the preceding claims, characterized in that the heat exchanger has a second housing element (8) but no first housing element (6, 7).