Heat exchanger arrangement and manufacturing process

Abstract

Heat exchanger arrangement, for example for an internal combustion engine, with a brazed radiator block (1) having flow paths (10) formed from pairs (P) of plates (11A, 11B) and flow channels (3) between the plate pairs, wherein at least one plate (11A) of each plate pair has a plate extension (12) and wherein the brazed radiator block (1) is arranged in a housing (2) and is sealed at its circumference against the housing (2), characterized in that at least one plate cutout (14) or a slot (14) and a protrusion (15) in the plate extension (12) associated with the plate cutout (14) or the slot (14) are arranged in a bending edge (13) of each of the plate extensions (12).

Description

The invention relates to a heat exchanger arrangement, for example for an internal combustion engine, having a soldered cooler block which has flow paths formed from pairs of plates and flow channels between the plate pairs, wherein in each case one plate of each plate pair has a plate extension, wherein the soldered cooler block is arranged in a housing and is sealed at its periphery with respect to the housing walls.The invention also relates to a method of manufacturing heat exchanger assemblies.The heat exchanger arrangement described is known from the internal prior art DE 10 2012 008 700 A1, but also from DE 3 826 244 A1 ascertained in the test method.WO 2013 / 078530, A1 discloses a heat exchanger including a plurality of plate pairs spaced apart from each other, each plate pair defining a flow channel for the flow of a first fluid. US 4880954 A describes a laminated heat exchanger comprising a plurality of parallel spaced tube elements having tanks at one end and fins disposed between adjacent tube elements.The plate extensions mentioned have the task in the earlier patent application of blocking the flow through the flow channels by means of the charge air to be cooled in the region of their arrangement and thereby directing the charge air onto the center of the radiator core, where the heat exchange can be carried out more effectively. They also form a largely smooth contour on the cooler block, which can be more easily sealed off from the housing in order to avoid bypasses. This task can also be assigned to the plate extensions from DE 3 826 244 A1, which otherwise describes an oil cooler.It has now been found that the quality of the seal is not yet good enough. An uncooled air stream may still bypass between a casing wall and the radiator core, thereby compromising the efficiency of the heat exchange. The incorporation of additional gaskets as provided in numerous other prior art publications is not desirable from a cost standpoint.U.S. Pat. No. 5,937,935 A describes a heat exchanger and its production method. There, it is provided to produce the plates of the heat exchanger from a sheet metal strip, wherein the plates are connected to one another and remain connected in each case by means of two bendable connecting webs. The connecting webs, which have the reference numerals 27 and 29 there, are bent over in the sense of a fold during the subsequent formation of a plate stack. Two of the disks in each case can be considered as a pair of disks. In the mentioned pull, corrugated ribs are inserted in each case between two plate pairs, after which the plate stack or the cooler block produced in this way can be soldered. This brazed radiator core is not particularly critical in its outer dimensions because it is not inserted into a housing but is placed like a radiator in a cooling air stream which flows freely through the corrugated fins to thereby cool a cooling liquid flowing within the plate pairs.The object of the invention is primarily to provide a heat exchanger arrangement which leads to a further improved sealing between the radiator core and the housing and is favourable from the point of view of costs.The solution according to the invention to this object is achieved by a heat exchanger arrangement which has the features of claim 1.An important aspect of the invention is seen in the fact that the plate extensions are formed in such a way that a prescribed dimension of the soldered radiator core can be produced by means of forming the plate extensions. A configuration according to the invention is considered to be particularly simple and advantageous, which has at least one plate cutout or a slot in a bending edge of each of the plate extensions and has at least one bulge in the plate extensions.In a practical embodiment it is provided that several plate cutouts or slots are arranged in the bending edge, with each cutout being assigned a corresponding bulge in the plate extension.The provision of a bending edge on the plate extension, already during the production of the plates, is not absolutely necessary. The plate extension can initially also extend in the direction of the plate plane, wherein a bending edge can be produced only in the course of the forming process on the soldered radiator core, according to the production method described below, whereby the length of the radiator core is shortened.The inventor has found that the cooler block is distorted during the soldering process. During soldering (slight) movements of the plate pairs and of the ribs which are arranged between the plate pairs take place, which probably mainly cause the mentioned drawing. The result of this is that the dimensions of the radiator core vary slightly, which results in harmful bypasses between the radiator core and the housing.On the basis of this finding, the inventor has arrived at the proposed invention, whereby the insertion of additional seals between the cooler block and the housing can also be substantially dispensed with.According to the manufacturing method for a heat exchanger arrangement, a calibration of the soldered cooler block is carried out in a forming tool. Calibration results in a perfectly fitted radiator core that has at least appreciably smaller or no air bypasses. The production method according to the invention can also be used for heat exchanger arrangements whose soldered cooler block is constructed differently from that of the heat exchanger arrangement according to the invention. Such cooler blocks have, for example, flat tubes instead of plate pairs.The proposed plate extensions are material additions to the plates. The plates are accordingly longer than they would have to fulfil the actual function of the radiator core.The invention is also based on the finding that such material additions can be used to compensate manufacturing tolerances. However, they are generally not cut off, as is otherwise customary in other assembly work, but rather are shaped, so that the soldered cooler block, after the mentioned calibration by means of a shaping tool or the like, has the prescribed dimension.In other words, the material additions or the plate extensions are used according to the invention to improve the sealing of the radiator core in the housing.Further features are contained in the dependent claims, which are not listed at this point merely to avoid repetitions. Furthermore, the further features and their effects also emerge from the following description of preferred exemplary embodiments of the invention, in which reference is made to the appended drawings.Brief Description of the DrawingsFIG. 1 is a perspective view of a heat exchanger assembly; FIG. 2 is a perspective view of the radiator core as part of the assembly; FIG. 3 is another perspective view of the radiator core; FIG. 4 shows a first plate with a plate extension prior to calibration of the radiator core; FIG. 5 ashows the first plate after calibration; FIG. 5 bshows another view of the first plate of FIG. 5 a; FIG. 6 shows a second plate with a lamella lying in a flow path; FIGS. 7, 8 to 9 show the mounting of the radiator core in a housing with or without an elastic sealing lip; FIG. 10 shows a sealing lip used as an option in section; FIG. 11 shows the already soldered cooler block in a forming tool;The heat exchanger arrangement as shown in FIGS. 1, 8 and 9 is used as a direct charge air cooler in a motor vehicle for cooling compressed charge air supplied to an internal combustion engine. It can also be used for other purposes and also outside of motor vehicle applications.In FIGS. 1, 2 to 3, an inlet connection 50 and an outlet connection 60 for a cooling liquid can be seen, which are fastened to a twin plate 5 which belongs to a soldered radiator core 1. The external features of the housing 2 shown in FIG. 1 among others will be discussed here only insofar as inlets for charge air LL to be cooled and outlets for cooled charge air (not shown) are located thereon, which outlets are marked by block arrows.The radiator core 1 has cooling liquid flow paths 10 which in the illustrated embodiments are formed of pairs P of plates 11A, 11B. Between the plate pairs P there are flow channels 3 in which cooling ribs 30 are arranged. The charge air LL to be cooled flows through the flow channels 3 with the cooling ribs 30.The cooling liquid and the charge air flow through the cooler block 1 approximately in countercurrent, whereby a high efficiency of the heat exchange is achieved. The counter-flow is realized in that lamellae 40 are located in the flow paths 10, which allow a flow in the longitudinal and transverse direction. In order to force the cooling liquid in the transverse direction, in each flow path 10 there is a first edge channel 41 between the lamella 40 and the edge of the flow path 10, which edge channel 41 is in flow connection with the inlet 50, and a second edge channel 42, at the opposite edge of the flow path 10, is in connection with the outlet 60 (FIG. 6 ). There are also positioning aids 43 for the blade 40 in the flow paths 10 formed by protrusions in the edge of the plate 11B and matching cutouts in the blade 40. In the pre-assembly, the plate 11A shown in FIGS. 5 aand 5 band the plate 11B shown in FIG. 6 are joined to the sipe 40 to form a plate pair P. For further details in this respect, reference is made to DE 10 2012 006 346 A1.The cooler block 1 already inserted into the housing 2 in FIG. 1 has been soldered beforehand in a soldering furnace, for which purpose reference is made to the usual technique. The structure of the radiator core 1 already outlined above is evident with the clarity necessary here from FIGS. 2 and 3.One plate 11A of each plate pair P has a plate extension 12, and the plate extensions 12 are designed such that a prescribed dimension of the soldered radiator core 1 can be produced by forming the plate extensions 12. In the exemplary embodiment, to achieve this result, each of the plate extensions 12 has a bending edge 13. Three plate cutouts 14 or slots 14, for example, are located in the bending edges 13, and the plate extensions 12 are furthermore provided with bulges 15, wherein the bulges 15 are each assigned to a plate cutout 14. This means that the bulges 15 extend approximately over the length of a plate cutout 14. Between the plate cutouts 14 or the slots 14 there is a web 16 in the bending edge 13, and it has proven advantageous to provide a comparable plate cutout 14 with a bulge 15 also at the edge of the plate 11B, as FIG. 6 likewise shows.From the comparison of FIGS. 4 and 5 a, the forming of the plate extensions 12 which takes place in the course of the calibration of the radiator core 1 in a forming tool can be seen. As can be seen, the bulges 15 in FIG. 5 a(also in FIG. 6 ) are flatter than those in FIG. 4, which is the result of the forming process shown in FIG. 11.The radiator core 1 therefore has a length dimension perfectly fitting into the housing 2. The height of the cooler block 1 is also calibrated in the forming tool, for which purpose the forming tool acts on an elastic sealing strip 7 in the direction of the arrow, FIG. 2. In this case, the legs of the sealing strip 7 can be bent slightly open. As a result, the sealing strip 7 will abut with the required contact pressure in the bulge 21 (FIG. 7 ) of the housing 2 and improve the sealing.The plate extensions 12 may also have a different configuration. They must in any case be suitable for producing a predetermined dimension of the radiator core 1 by means of their forming. This can be effected, for example, by the bending edge being produced only during the calibration of the radiator core 1 described below (not shown).In the embodiments shown, the plate extensions 12 extend approximately as far as the adjacent plate pair P.Inside the housing 2, a ledge 20 is disposed that extends in an insertion direction of the radiator core 1 into the housing 2. FIG. 7 shows a plurality of strips 20 on opposite first and second housing walls 2 a, 2 b. The strips 20 are formed integrally with these housing walls 2a, 2b.The strip 20 on the front housing wall 2 acan optionally cooperate with an elastic sealing lip 4 in order to seal a distance of the strip 20 up to the soldered cooler block 1 even better (FIGS. 8 and 10 ). The provision of such sealing lips 4 is related to the particular shape of the plates 11A, 11B having the inlets and the outlets seated in projections of the plates 11 with a space therebetween to be better sealed in which the sealing lip 4 is positioned.The strips 20 cooperate with the mentioned webs 16 in order to improve the sealing and a fixing in position of the radiator core 1 in the housing 2.The soldered radiator core 1 has a tip plate 5 projecting beyond the circumference thereof (already mentioned above) for fastening in the housing 2, more precisely at the edge of an insertion opening of the housing 2, which cannot be seen here.A base plate 6 is also located on the cooler block 1 (FIG. 2 ). The aforementioned elastic sealing strip 7 has been fastened to the base plate 6 by means of tongues 8 and openings 9 after the radiator core 1 has been soldered. The elastic sealing strip 7 assumes the sealing with an adjoining third housing wall 2c. For this purpose, the third housing wall 2 chas a curvature 21, in which the sealing strip 7 comes to rest (FIG. 7 ).As can be seen from the representations, the sealing strip 7 and the at least one bulge 15 in the plate extensions 12 are located approximately on a common cross-sectional plane of the radiator core 1, approximately in the center of the radiator core 1 in the exemplary embodiment.The aforementioned base plate 6 has also been provided with a plate extension 12 which, in the embodiment, is formed identically to those on the plates 11A. A further panel extension 12a is located on the opposite side of the panel 11A which also has a bending edge 13a. The further plate extension 12 aextends in the same direction as the first-mentioned plate extensions 12, but it has a different function, since it is a positioning aid for the cooling ribs 30 in the flow channels 3 in order to facilitate the preassembly of the radiator core 1 (FIGS. 3 and 5 b ).The aforementioned FIG. 11 shows a cooler block 1 located in the forming tool 18 The cooler block 1 is placed in a receptacle 19 of the tool 18. Horizontally and vertically movable carriages act on the cooler block 1 and produce the prescribed dimension thereof.

Claims

Heat exchanger arrangement, for example for an internal combustion engine, having a soldered cooler block (1) which has flow paths (10) formed from pairs (P) of plates (11A, 11B) and flow channels (3) between the plate pairs, wherein at least one plate (11A) of each plate pair has a plate extension (12), and wherein the soldered cooler block (1) is arranged in a housing (2) and is sealed at its periphery with respect to the housing (2), characterized in that at least one plate cutout (14) or a slot (14) and a bulge (15) assigned to the plate cutout (14) or the slot (14) are arranged in a bending edge (13) of each of the plate extensions (12).Heat exchanger arrangement according to claim 1, characterised in that the bent plate extensions (12) extend as far as the adjacent plate pair (P).Heat exchanger arrangement according to Claim 1, characterized in that webs (16) connecting between the plate cutouts (14) or the slots (14) are arranged in the bending edge (13).Heat exchanger arrangement according to one of the preceding claims, characterized in that at least one strip (20) is arranged in the housing (2), which strip extends in an insertion direction of the cooler block (1) into the housing (2)Heat exchanger arrangement according to claims 1 and 4, characterised in that a plurality of strips (20) extend on opposite first and second housing walls (2a, 2b), which are formed integrally with these housing walls (2a, 2b).Heat exchanger arrangement according to claim 5, characterised in that at least one of the strips (20) abuts against an elastic sealing lip (4) in order to seal a distance of the strip (20) as far as the soldered cooler block (1).Heat exchanger arrangement according to one of the preceding claims, characterized in that the strips (20) cooperate with the webs (16) in order to improve the sealing and fixing of the radiator core (1) in position in the housing (2).Heat exchanger arrangement according to one of the preceding claims, characterized in that the soldered cooler block (1) has a twin plate (5) projecting over the circumference thereof for fastening in the housing (2) and a base plate (6).Heat exchanger arrangement according to one of the preceding claims, characterized in that an elastic sealing strip (7) is arranged on the base plate (6), which strip assumes the sealing with an adjoining third housing wall (2c), wherein the third housing wall (2c) has a curvature (21) in which the sealing strip (7) comes to bear.Heat exchanger arrangement according to Claim 9, characterized in that the elastic sealing strip (7) is composed of metal and is attached to the base plate (6) after the cooling block (1) has been soldered, for which purpose deflectable tongues (8) engage through openings (9) in the sealing strip (7).Heat exchanger arrangement according to one of the preceding claims, characterized in that the base plate (6) also has a plate extension (12) which is formed according to one of Claims 1 to 3.Heat exchanger arrangement according to one of the preceding claims, characterized in that the sealing strip (7) and the at least one bulge (15) in the plate extensions (12) are arranged on a common cross-sectional plane of the radiator core (1), centrally of the radiator core.Heat exchanger arrangement according to any of the preceding claims, characterized in that a further plate extension (12a) is arranged on the opposite side of the plate (11A), which also has a bending edge (13a), wherein the further plate extension (12a) extends in the same direction as the first-mentioned plate extension (12) up to the adjacent plate pair (P).Heat exchanger arrangement according to claim 13, characterised in that the further plate extension (12a) is a positioning aid for a cooling fin (30) located in the flow channels (3).Heat exchanger arrangement according to one of the preceding claims, characterized in that charge air (LL) or exhaust gas flows through the flow channels (3) of the radiator core (1) and a liquid coolant flows through its flow paths (10), wherein lamellae (40) are located in the flow paths (10).Heat exchanger arrangement according to claim 15, characterised in that the fins (40) leave a first edge channel (41) in the flow paths (10), which is in communication with an inlet (50) for the liquid coolant, and a second edge channel (42), which is in communication with the outlet, so that the coolant must flow into the first edge channel (41), through the fins (40) and through the second edge channel, so that the charge air (LL) and the coolant in the cooler block (1) have approximately the countercurrent direction.

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