Abstract:
A heat exchanger for cooling a flow of media, comprising a plurality of pipes. The pipes are each received in a respective pipe base at the ends, and the pipes are received in a housing between the two pipe bases, the housing being connected to the pipe bases in a fluid-tight manner. A coolant channel is formed by a shaped region oriented outwards along an outer wall which delimits the housing. The coolant channel has an opening oriented in the direction of the inner volume of the housing, and the coolant channel is in fluidic communication with the inner volume of the housing via the opening. The opening is at least partly covered by a panel, and the panel is arranged on the housing outer wall surface oriented inwards, the outer wall having the coolant channel. A gap is formed between an edge, which delimits the opening, and the panel.

Description:
[0001]    This nonprovisional application is a continuation of International Application No. PCT/EP2015/065987, which was filed on Jul. 13, 2015, and which claims priority to German Patent Application No. 10 2014 213 718.7, which was filed in Germany on Jul. 15, 2014, and which are both herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    2. Field of the Invention 
         [0003]    The invention relates to a heat exchanger for cooling a media flow, comprising a plurality of tubes, whereby the tubes are received at the ends in a respective tube sheet, whereby the tubes between the two tube sheets are received in a housing, which is connected to the tube sheet in a fluid-tight manner, whereby a coolant channel is formed by an outwardly directed shaped region along an outer wall delimiting the housing, whereby the coolant channel has an opening which is directed in the direction of the inner volume of the housing and via which the coolant channel is in fluid communication with the inner volume of the housing. 
         [0004]    2. Description of the Background Art 
         [0005]    The charge air, which is used in modern internal combustion engines to increase performance by means of a turbocharger, can be cooled by so-called charge air coolers so as to enable as great an increase in performance as possible. For this purpose, a heat transfer can be produced between the charge air and a coolant in a charge air cooler. 
         [0006]    The charge air can be conveyed for cooling, for example, through tubes around which cooling air flows. An alternative design of a charge air cooler provides that the charge air is flowed through a plurality of tubes, while a liquid coolant flows around the tubes. The coolant itself can preferably be cooled again in a further heat exchanger to remove from the coolant the amount of heat that it has taken up from the charge air during the heat transfer. 
         [0007]    DE 10 2006 043 526 A1 shows a charge air cooler comprising a plurality of tubes, which run between two collecting tanks and fluidically connect the collecting tanks to one another. The charge air to be cooled can be flowed through the collecting tanks and tubes. The tubes lead totally or partially through a chamber through which a coolant can flow. A heat transfer between the charge air and the coolant can be produced in this way, as a result of which cooling of the charge air can be achieved. 
         [0008]    It is disadvantageous in the devices in the prior art that the through-flow of the heat exchanger with the coolant is not optimally designed, as a result of which so-called dead zones can occur which are characterized in that the coolant does not flow through them or flows only to a very small extent. Therefore, stagnation of the coolant can occur. 
         [0009]    In particular due to the increasing charge air temperature in modern internal combustion engines at the inlet side of the heat exchanger, boiling of the coolant can occur, which has a disadvantageous effect on the cooling performance of the heat exchanger. This disadvantage arises especially often and markedly in charge air coolers in which the charge air and the coolant are conveyed in countercurrent to one another. 
       SUMMARY OF THE INVENTION 
       [0010]    It is therefore an object of the present invention to provide a heat exchanger that reduces or totally eliminates the formation of stagnation of the coolant and thus enables better flow of the coolant through the heat exchanger. 
         [0011]    An exemplary embodiment of the invention provides a heat exchanger for cooling a media flow, comprising a plurality of tubes, whereby the tubes are received at the ends in a respective tube sheet, whereby the tubes between the two tube sheets are received in a housing, which is connected to the tube sheet in a fluid-tight manner, whereby a coolant channel is formed by an outwardly directed shaped region along an outer wall delimiting the housing, whereby the coolant channel has an opening which is directed in the direction of the inner volume of the housing and via which the coolant channel is in fluid communication with the inner volume of the housing, the opening being covered at least partially by a panel, whereby the panel is disposed on the inwardly directed surface of the outer wall of the housing, which has the coolant channel, whereby a gap is formed between an edge, delimiting the opening, and the panel. 
         [0012]    The main extension direction of the coolant channel preferably runs in a direction transverse to the main extension direction of the tubes. The coolant channel can therefore be used to distribute the coolant over the width of the heat exchanger or to collect the coolant from the width of the heat exchanger and to carry it out of the heat exchanger. The coolant within the heat exchanger flows around the tubes and flows in particular in the free spaces formed between the tubes. 
         [0013]    The heat exchanger preferably has two opposite narrow sides and two opposite broad sides. The width of the heat exchanger is measured between the opposite narrow sides, whereas the height is measured in the direction of the main extension direction of the tubes. The depth of the heat exchanger is measured between the opposite broad sides. 
         [0014]    A panel, which at least partially covers the coolant channel opening, directed toward the inner volume of the heat exchanger, is especially advantageous, because by reducing the opening cross section a slowing down of the coolant flow into the coolant channel or out of the coolant channel can be achieved. The slowing down furthermore leads to an increase in flow resistance, which in turn has a positive effect on the maximum achievable cooling performance. 
         [0015]    Furthermore, the flow direction of the coolant can be influenced by a panel. In particular, by the orientation of the gap, which arises due to the only partial covering of the opening of the coolant channel, the flow of the coolant can be influenced such that a greater flow to the at least one tube sheet is achieved. It is especially advantageous in this case, if the tube sheet at which the higher temperatures arise during operation is supplied increasingly with the coolant. In a heat exchanger with a countercurrent flow, due to the high temperatures of the air to be cooled this is the tube sheet that is disposed adjacent to the coolant outlet. 
         [0016]    The panel can form a gap on the coolant channel side facing the tube sheet, so that the coolant can flow past the coolant channel along the panel and flows further in the direction of the tube sheet, before it is redirected at the tube sheet and flows over through the gap into the coolant channel. 
         [0017]    The panel is especially advantageous in order to leave the cross-sectional area of the coolant channel as large as possible, in order to assure a flow as undisturbed as possible within the coolant channel, and simultaneously to form a restriction site, which increases the pressure loss during the flowing over of the coolant between the inner volume and the coolant channel, in order to achieve a selective influence on the direction of the coolant flow. This is particularly advantageous compared with a merely smaller design of the coolant channel, which would lead to a substantially poorer distribution of the coolant along the width of the heat exchanger. 
         [0018]    The coolant channel can be disposed at a first end region of the housing, the region being closed off by one of the tube sheets. This is especially advantageous in order to form the overflow site of the coolant from the inner volume into the coolant channel or vice versa as close as possible to the tube sheets, in order to form a flow section through which the coolant flows as large as possible within the heat exchanger. 
         [0019]    It is especially advantageous, if the width of the gap between the panel and the edge, delimiting the opening, increases or decreases in the direction of the main extension direction of the coolant channel. 
         [0020]    A pressure loss that is variable over the width of the heat exchanger can be produced by an increasing or decreasing gap width along the main extension direction of the coolant channel, as a result of which the flowing over of the coolant from the inner volume into the coolant channel is additionally promoted or made more difficult. This is it is especially advantageous to achieve a still far-reaching influence on the coolant flow. 
         [0021]    The opening can have a rectangular cross section, whereby the gap is formed between the panel and the edge delimiting the opening and facing the first end region of the housing. 
         [0022]    It can be achieved by such an arrangement of the gap that the coolant flows past the panel increasingly in the inner volume of the heat exchanger and flows into the coolant channel via the gap only after flowing against the tube sheet. A longer flow section for the coolant is realized in this way, and simultaneously a greater flow against the tube sheet. This results in a higher heat uptake by the coolant and in an improved heat removal from the tube sheet. 
         [0023]    The panel can be formed by a planar, plate-like element. A planar, plate-like element is especially advantageous in forming the panel as space-saving as possible. As a result, an additional negative influence on the coolant flow within the heat exchanger due to the panel can also be prevented. 
         [0024]    The outer wall of the housing, the wall having the coolant channel, on its inner side at the edge, delimiting the opening, can have an at least partially circumferential depression into which the panel can be inserted. This is especially advantageous to connect the panel to the inner side of the outer wall such that it terminates flush with the wall and produces no overhang. Preferably, the depression has a depth which corresponds to the material thickness of the panel. In an alternative embodiment, the depression has a depth that corresponds to the material thickness of the panel and an additional seal. By the flush attachment of the panel, a planar attachment of the tubes to the inner side of the wall and the panel can be achieved, as a result of which the sealing between the housing and the tubes is simplified. 
         [0025]    The coolant channel can be in fluid communication with a fluid connection disposed in the extension of the coolant channel, whereby the fluid connection is formed as a fluid inlet or fluid outlet. 
         [0026]    The coolant channel can be formed in the axial extension of a fluid connection, so that the coolant can flow directly out of the fluid connection into the coolant channel or vice versa. 
         [0027]    The fluid connection can be in fluid communication with the coolant channel via a funnel-shaped area, whereby the flowing of the coolant between the inner volume of the heat exchanger and the fluid connection occurs entirely via the coolant channel. 
         [0028]    An especially flow-enhancing transition can be achieved by a fluid-tight connection of the fluid connection to the coolant channel via a funnel-shaped area. A flowing over between the fluid connection and the inner volume entirely by means of the coolant channel is especially advantageous to prevent flow around the restriction site formed by the panel or by the gap. 
         [0029]    The coolant channel can be completely covered by the panel in the direction of its main extension direction. This is advantageous to assure that a coolant transfer from the inner volume into the coolant channel or vice versa occurs as close as possible to the particular adjacent tube sheet, and the longest possible flow path overall for the coolant within the heat exchanger is produced. The coolant flow in addition can be redirected in this way selectively in the direction of the tube sheet, as a result of which the heat removal at the tube sheet is improved. 
         [0030]    The panel can be bolted to the housing. In alternative embodiments, the panel can also be soldered to the housing or be connected to the housing by another fastener known to one skilled in the art or from the prior art. 
         [0031]    The panel can have a water barrier on the side facing the inner volume of the housing and/or the coolant channel. A water barrier is especially advantageous to prevent a leakage flow along the contact surfaces of the panel at the housing. The water barrier acts as a seal to assure a targeted transport of the coolant through the gap. 
         [0032]    The coolant channel can form a bypass through which the coolant can flow past the tubes disposed in the housing and into the free spaces formed between the tubes. The coolant channel is used preferably for distributing or collecting the coolant over the width of the heat exchanger. In this case, the coolant passes from the coolant channel into the free spaces formed between the tubes or flows out of these free spaces into the coolant channel. 
         [0033]    The panel can at least partially cover the opening of the coolant channel at a fluid connection serving as the fluid outlet, whereby the coolant can flow from the direction of the tube sheet adjacent to the coolant channel along the gap into the coolant channel. This is especially advantageous to achieve that the coolant flow before flowing over into the coolant channel is redirected first to the adjacently disposed tube sheet. In particular because the heat exchangers are flowed through preferably in a countercurrent principle, an especially high temperature arises at the tube sheet, which is disposed adjacent to the coolant outlet, due to the hot air flowing into the tubes. 
         [0034]    The housing can have a fluid connection at each narrow side, whereby in each case in the axial extension of the fluid connection a coolant channel produced by an outwardly shaped region on a broad side of the housing, whereby the coolant channels are disposed on the same broad side of the housing. The arrangement of the fluid connections on opposite narrow sides is especially advantageous to obtain an optimal distribution of the coolant over the entire width of the heat exchanger. 
         [0035]    The housing can have, for example, two coolant channels, whereby one of the coolant channels is in fluid communication with a fluid outlet and the other coolant channel is in fluid communication with a fluid inlet, whereby one or both coolant channels are at least partially covered by a panel. This is advantageous to achieve the most optimal redirecting possible of the coolant flow at the coolant inlet and/or at the coolant outlet and thus to improve the heat transfer between the air and the coolant. It is advantageous in particular in this case, if by the arrangement of the panel/s the flow path of the coolant within the heat exchanger is increased and the coolant flows increasingly into a tube sheet or both tube sheets to produce a better heat transport away from the tube sheets. 
         [0036]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes, combinations, and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
           [0038]      FIG. 1  shows a side view of a heat exchanger with a panel, which at least partially covers one of the coolant channels; 
           [0039]      FIG. 2  shows a detailed view of a coolant channel produced by a shaped region of the housing; 
           [0040]      FIG. 3  shows a detailed view of the panel, which at least partially covers the coolant channel; 
           [0041]      FIG. 4  shows a view of the area of the heat exchanger, which has the coolant channel covered by the panel; 
           [0042]      FIG. 5  shows a perspective view of the heat exchanger, whereby the housing surrounding the tubes is not shown in its entirety; 
           [0043]      FIG. 6  shows a perspective view of the heat exchanger, whereby the tube sheets are shown in which the tubes are received at the ends; 
           [0044]      FIG. 7  shows a side view of the heat exchanger, whereby a sectional view through the heat exchanger along the main extension direction of the tubes is shown in the right section of  FIG. 7  and a sectional view along a direction transverse to the main extension direction of the tubes in the bottom section; 
           [0045]      FIG. 8  shows a detailed view of the coolant channel, which is at least partially covered by the panel; 
           [0046]      FIG. 9  shows a side view of the heat exchanger in the left section and a sectional view through the heat exchanger along the main extension direction of the tubes in the right section; 
           [0047]      FIG. 10  shows a detailed view according to  FIG. 8 , whereby the tubes of the heat exchanger are not shown; 
           [0048]      FIG. 11  shows a side view of the broad side of the heat exchanger, whereby the panel is mounted and at least partially covers the bottom coolant channel; 
           [0049]      FIG. 12  shows a view of a rectangular, plate-like panel; 
           [0050]      FIG. 13  shows a view of an alternatively designed embodiment panel with at least one obliquely extending outer edge; 
           [0051]      FIG. 14  shows an illustration of the velocity vectors of the coolant flow within the heat exchanger, whereby the coolant channel on the coolant outlet side is not covered by a panel; and 
           [0052]      FIG. 15  shows an illustration of the velocity vectors of the coolant flow within the heat exchanger, whereby the panel is arranged over the coolant channel on the coolant outlet side. 
       
    
    
     DETAILED DESCRIPTION 
       [0053]      FIG. 1  shows a view of a heat exchanger  1 . Heat exchanger  1  is formed by a plurality of tubes  4  which are arranged parallel to one another and at the ends are each received in a tube sheet  2  located at the top and a tube sheet  3  located at the bottom. In the illustration in  FIG. 1 , the housing surrounding tubes  4  is not shown. A fluid connection  7  is shown at the top left end region and a second fluid connection  6  at the bottom end region. In an advantageous embodiment, fluid connection  7  is used to supply the coolant, whereas fluid connection  6  is used to remove the coolant from heat exchanger  1 . The housing has a first end region  28 , which represents the end region of the housing that is closed off by tube sheet  3 . Tube sheet  3  in this case is located adjacent to fluid connection  6  formed as a fluid outlet. Especially high temperatures, which can lead to boiling of the coolant, arise in particular at the tube sheet  3 . 
         [0054]    The heat exchanger  1  has two opposite narrow sides  10  and two likewise opposite broad sides  11 . Tubes  4  made preferably as flat tubes are arranged next to one another along broad sides  11 . Narrow sides  10  and broad sides  11  form the outer walls of the housing. 
         [0055]    A media flow, which is preferably formed by air, used as charge air for charging an internal combustion engine, flows through tubes  4 . Hereinafter, air is always mentioned as the medium flowing through the tubes, whereby this does not represent a restriction to air. A coolant flows through the housing of heat exchanger  1 , as a result of which in particular the air within tubes  4  is cooled. 
         [0056]    A rectangular, plate-like panel  5  is disposed in the interior of heat exchanger  1 . The panel is connected to one of the inner surfaces of the housing (not shown), for example, by screwing together or by a tox connection, and covers in particular a section of an inwardly directed opening of coolant channel  13 , which is formed in the outer wall of the housing. 
         [0057]    A coolant channel  13  is formed in the outer wall of the housing both in the extension of fluid connection  7  and in the extension of fluid connection  6 . Coolant channels  13  can be used depending on the through-flow direction either for distributing the coolant along broad side  11  of heat exchanger  1  or for collecting the coolant along broad side  11 . 
         [0058]    In  FIG. 1  panel  5  is disposed over coolant channel  13 , which is associated with fluid outlet  6 . In alternative embodiments, the coolant channel of the fluid inlet can also be partially covered by a panel. 
         [0059]    Furthermore, a coordinate system with spatial directions  8  and  9  is shown in  FIG. 1 . Spatial direction  8  extends parallel to the main extension direction of tubes  4 , whereas spatial direction  9  extends transverse to tubes  4  along the width of the heat exchanger. Both broad sides  11  of heat exchanger  1  extend along spatial direction  9 . The two spatial directions  8  and  9  also serve as a basis for the exemplary embodiments in the following figures. 
         [0060]      FIG. 2  shows a detailed view of a coolant channel  13 . As can be seen in  FIG. 2 , coolant channel  13  is formed by a shaped region of housing  12  outwardly from tubes  4 . Coolant channel  13  is formed on one of broad sides  11  of housing  12 . Coolant channel  13  has an inwardly directed opening  14 , which is delimited by circumferential edge  19 . The coolant can flow over between coolant channel  13  and the inner volume of housing  12  through opening  14  or the cross section of opening  14  not covered by panel  5 . 
         [0061]    The inner volume of housing  12  is substantially formed by the free spaces between tubes  4 . Because housing  12  adjoins the narrow sides of tubes  4 , a through-flow of the inner volume within housing  12  can occur only along the free spaces between tubes  4 . Depending on the through-flow direction, the coolant can flow over from coolant channel  13  into the free spaces between tubes  4  or flow over from the free spaces into coolant channel  13 . 
         [0062]      FIG. 3  shows a detailed view of coolant channel  13 , which is partially covered by panel  5 . The bottom section of heat exchanger  1  of  FIG. 1  is illustrated in  FIG. 3 . Panel  5  serves as a barrier for the coolant to improve the flow distribution. 
         [0063]      FIG. 4  shows a further detailed view, whereby panel  5  can be seen, which can be connected via holes  15  to housing  12 , which is not shown in  FIG. 4 . Tubes  4  and the free spaces formed between tubes  4  can be seen in the background behind panel  5 . As can be seen in  FIG. 4 , the entire opening of coolant channel  13  is not covered by panel  5 , but only a defined section. A gap between panel  5  and the edge, which delimits the opening and is formed by the wall of housing  12 , forms in particular along the bottom edge region of coolant channel  13 . A coolant transfer into coolant channel  13  or out of it can be realized by the gap, which is shown in detail in the following figures. 
         [0064]      FIG. 5  shows a further view of a heat exchanger  1 , whereby housing  12  is only partially indicated. Heat exchanger  1  in  FIG. 5  is shown situated horizontally. 
         [0065]    Both coolant channels  13 , which are formed on the upwardly directed broad side  11 , are indicated by line drawings in  FIG. 5 . In particular the opening cross-sectional surface of fluid connection  7  with the reference character  16  is shown in left coolant channel  13 . 
         [0066]    As can be seen in  FIG. 5 , panel  5  covers only a section of the opening of right coolant channel  13 . The covered region, in particular along spatial direction  8 , is shown with the reference character  17 . The gap, which forms a transfer surface between the free spaces between tubes  4  and coolant channel  13 , is shown with the reference character  18 . The opened gap  18  acts in particular as a restriction site, because it substantially reduces the actual transfer surface from the inner volume of heat exchanger  1  into coolant channel  13 . A restriction site can be produced by providing a panel  5 , without the actual flow cross section of coolant channel  13  being changed, as a result of which further an optimal through-flow of coolant channel  13  is assured. 
         [0067]      FIG. 6  shows a further perspective view of heat exchanger  1 . Housing  12  is shown with both shaped coolant channels  13  and fluid connections  6  and  7 , located in the extension of the particular coolant channels  13 , and both tube sheets  2  and  3 . Coolant channels  13  are both located on the same broad side  11  of heat exchanger  1 , whereas fluid connections  6  and  7  are located on the respectively opposite narrow sides  10 . The first end region  28  of the housing represents the end region at which especially high temperatures arise due to the flow of air in the tubes. 
         [0068]      FIG. 7  in the left top area shows a side view of heat exchanger  1  according to  FIG. 6 . In the left top area of  FIG. 7 , the sectional plane A-A, which extends along main extension direction  8  of tubes  4 , is shown along heat exchanger  1 . Furthermore, sectional plane B-B is shown, which extends along spatial direction  9 . Section A-A through heat exchanger  1  is shown in the right part of  FIG. 7 . It can be seen here that a further shaped section  20 , through which the coolant can also flow within heat exchanger  1 , is provided approximately at the same height opposite to coolant channels  13  on the opposite broad side  11 . Both coolant channels  13  and shaped regions  20  can extend over another section of broad sides  11 , so that in these areas  13 ,  20  an overflow of the coolant between the free spaces, which are formed between tubes  4 , is possible. 
         [0069]    Section B-B, which cuts through bottom coolant channel  13  and fluid connection  6 , is shown in the bottom part of  FIG. 7 . Flat tubes  4 , which are arranged parallel to one another and are received in housing  12 , are shown in section B-B. Fluid connection  7  is shown in the left area of section B-B. 
         [0070]      FIG. 8  shows a detailed view of coolant channel  13  at fluid connection  6 . A portion of fluid connection  6  is covered by tubes  4 . Panel  5  is fixed to housing  12  in the exemplary embodiment of  FIG. 8 . Panel  5  extends parallel to the main extension direction of tubes  4  over a large section of opening  14  of coolant channel  13 . A gap  25 , which forms a transfer surface between coolant channel  13  and inner volume  23  of heat exchanger  1 , results between edge  19 , which delimits opening  14  and is formed by the wall of housing  12 , and panel  5 . Tube sheet  3  in which tubes  4  are received at the ends is indicated at the right end region of  FIG. 8 . 
         [0071]    Fluid connection  6  merges via a funnel-shaped area with coolant channel  13  at least partially delimited by panel  5 . Tube  4 , located directly adjacent to fluid connection  6 , can form with its wall, facing fluid connection  6 , a part of the funnel-shaped area. The funnel-shaped area is delimited further by the inner walls of housing  12 , as a result of which the coolant can flow out of fluid connection  6  only directly into coolant channel  13  or vice versa. 
         [0072]    Panel  5  is inserted in a depression  29 , which is formed at least partially circumferentially around opening  14 . Due to the insertion into depression  29 , the side of panel  5 , the side being directed toward inner volume  23  of heat exchanger, terminates flush with the wall having coolant channel  13 . As a result, an especially exactly fitting and sealing contact of tubes  4  with the inner side of housing  12  is possible. 
         [0073]      FIG. 9  in the left area shows a side view of a broad side  11  of heat exchanger  1 . In the area of bottom coolant channel  13 , holes, to which panel  5  can be attached, in housing  12  are shown with the reference character  14 . In the right part of  FIG. 9 , section C-C is shown, which passes along spatial direction  8  through heat exchanger  1 . 
         [0074]    Both coolant channels  13  and fluid connection  6  can be seen in section C-C. Furthermore, connection  21  is shown by which panel  5  is fixed relative to housing  12 . 
         [0075]      FIG. 10  shows a detailed view of coolant channel  13  with mounted panel  5 , which is connected via connection  21  to housing  12 . Tubes  4  are not shown in inner volume  23  in the illustration of  FIG. 10  in comparison with  FIG. 8 . Furthermore, gap  25  can be seen, which is formed between panel  5  and the edge delimiting the opening of coolant channel  13 . 
         [0076]      FIG. 11  shows a side view according to the left illustration in  FIG. 9 . In  FIG. 11 , panel  5  is mounted and connected along holes  15  to housing  12  of heat exchanger  1 . In  FIG. 11 , bottom gap  25  can be seen, which serves as a passage between coolant channel  13  and the inner volume of heat exchanger  1 . As can be seen further in  FIG. 11 , panel  5  is spaced apart from the inner wall of housing  12  along spatial direction  9 . This space can be covered, for example, by one of the tubes in the interior of heat exchanger  1 . In particular the funnel-shaped area, which forms the transition between fluid connection  6  and coolant channel  13 , can be formed along this space. A flowing over of the coolant into the inner volume in the area of the space is preferably prevented by walls, such as, for example, the walls of a tube  4 . 
         [0077]      FIG. 12  shows a view of the rectangular, plate-like panel  5  with holes  15 , by means of which panel  5  can be attached to housing  12 . 
         [0078]    Panel  5  is formed in particular by a plate-like element, which has large extensions along two spatial directions, whereas the extension in the third spatial direction, which is formed in  FIG. 12  as the surface normal to the plane of the drawing, is much smaller than in the two other spatial directions. 
         [0079]      FIG. 13  shows an alternatively shaped panel  26 , which is characterized in particular in that one of the edges has an oblique course along the main extension direction of panel  26 . It is achieved in this way that the gap, which forms between coolant channel  13  and panel  26 , increases or decreases with an increasing distance from the fluid connection. This depends on the orientation of panel  26  relative to fluid connection. Furthermore, panel  26  has beveled corners on the end region directed to the right. In an alternative embodiment, the panel can also have an edge with a serrated course, so that the gap is delimited on the one side by a serrated outline. 
         [0080]      FIG. 14  shows an illustration of velocity vectors  30  of the coolant flow within heat exchanger  1 . In  FIG. 14 , a heat exchanger  1  is shown without a panel in front of coolant channel  13 . It can be seen that vectors  30  are oriented in such a way that the coolant flow points primarily directly toward coolant channel  13  and only a small portion of the coolant is conveyed to bottom region  31 . Bottom region  31  corresponds to the region in which the tubes are received in the tube sheet. 
         [0081]    Because of the flow through heat exchanger  1  in countercurrent, high temperatures arise due to the hot air, flowing into the tubes in region  31 , particularly in bottom region  31 , which is disposed adjacent to the coolant outlet side. As a result, boiling of the coolant can occur in region  31 , which is disadvantageous with respect to the achievable cooling performance. The more coolant is supplied to bottom region  31 , the better the heat of the hot air can be removed, as a result of which a greater cooling performance in heat exchanger  1  can be produced. 
         [0082]      FIG. 15  shows an illustration of velocity vectors  30  in a heat exchanger  1  with an installed panel  5 . It can be seen in  FIG. 15  that a greater distribution of the coolant occurs toward bottom region  31  and toward formation  20  formed relative to coolant channel  13 . As a result, the coolant flows in an intensified manner along bottom region  31 , before it flows over through gap  25  into coolant channel  13 . Thus, a favorable effect on the coolant flow within heat exchanger  1  is created, as a result of which greater heat removal can be realized and the boiling of the coolant can be considerably reduced or totally prevented. Therefore, a greater flow through first end region  28  of the housing is achieved by panel  5 . 
         [0083]    The individual features of the exemplary embodiments of the previous  FIGS. 1 to 15  can also be combined in particular with one another.  FIGS. 1 to 15  have no restrictive nature with respect to material selection, the shape of the individual elements, and the arrangement of the individual elements relative to one another.  FIGS. 1 to 15  serve to clarify the inventive concept and do not restrict the solution to the shown exemplary embodiments. 
         [0084]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.