Abstract:
A vehicular heat exchange module, including first, second and third heat exchanger, with two of the heat exchangers being a radiator a charge air cooler. The heat exchangers include a core having a plurality of flat tubes with cooling ribs therebetween. At least one of the heat exchangers has a gradation whereby the one heat exchanger has a portion with a reduced thickness in the flow direction defining a free space, and at least one part of at least one of the other heat exchangers occupies the free space.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S)  
       [0001]     Not applicable.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     Not applicable.  
       TECHNICAL FIELD  
       [0004]     The present invention relates to heat exchangers, and more particularly a plurality of heat exchangers arranged one behind the other in a vehicle.  
       BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIOR ART  
       [0005]     Many applications require the use of a plurality of heat exchangers for different media and devices. For example, a radiator, a charge air cooler, a condenser and still other heat exchangers may be required in a vehicle, with such heat exchangers acted upon by cooling air and all arranged, for example, one behind the other in the flow direction of the cooling air in an attempt to compactly fit into a restricted available area.  
         [0006]     For example, such arrangements are known in numerous variations which cool the coolant of the drive motor, its charge air, the refrigerant of the air conditioner and additional operating media or to control their temperature. The cooling air is generally accelerated by means of a fan lying in front of or generally behind the arrangement in the direction of cooling air flow.  
         [0007]     Due to ever improving designs, the cooling power requirements of vehicle manufacturers are continuously increasing while and the space available in the vehicle is continuously being reduced, so that manufacturers of such arrangements have the challenge of finding innovative solutions. In addition, the arrangements must still be or remain very service-friendly.  
         [0008]     In order to increase cooling power of the arrangement, EP 522 288 B1 has suggested dividing the charge air cooler into two parts which are connected by means of a connection line carrying the charge air, with the two parts being arranged in front of and behind the central radiator. Between the two parts of the charge air cooler, additional heat exchangers, for example the condenser of the air conditioner, can be arranged in addition to the radiator.  
         [0009]     Two-stage cooling of charge air is also proposed in the cooling arrangement known from DE 44 37 946 C2. The charge air cooler, viewed in the direction of cooling air flow, was arranged in front of the radiator.  
         [0010]     A charge air cooler was located in the lower area of the arrangement as disclosed in DE 44 37 946 C2, viewed in the direction of cooling air flow, and also in front of the radiator. However, as a result of this arrangement, the radiator is undesirably acted upon by already pre-heated cooling air. In the mentioned prior art, the main concern, as previously mentioned, are arrangements with improved performance.  
         [0011]     In another prior art design, EP 360 362 A1 discloses a condenser having a gradation created by some of the flat tubes of a row of flat tubes being made shorter than the other flat tubes. The gradation was provided in order to correspond to an obstacle in the engine compartment. The objective pursued with this design for better space utilization in the vehicle is therefore apparent from this document.  
         [0012]     An air conditioning condenser has in the prior art previously been designed with a gradation, as is schematically in  FIG. 6  hereof. In that structure, a flat tube row consisting of several flat tubes was arranged as supercooling zone  70  for the refrigerant in front of the flat tube row  74  provided for condensation of the refrigerant. However, this type of gradation can scarcely be used to gain space, since condensers  40  ordinarily have a very limited depth, for example between 10 and 20 mm. In addition, this design has an adverse effect on the cooling power of the heat exchangers following in the direction of cooling air flow (e.g., on the cooling power of the radiator) because the cooling air is heated too strongly on flowing through the condenser. It has also been found that the performance of the condenser itself is not satisfactory.  
         [0013]     The present invention is directed toward overcoming one or more of the problems set forth above.  
       SUMMARY OF THE INVENTION  
       [0014]     In one aspect of the present invention, a vehicular heat exchange module is provided for exchanging heat with cooling air moving in a flow direction, including a first heat exchanger, a second heat exchanger comprising a radiator, and a third heat exchanger comprising a charge air cooler. The heat exchangers include a core having a plurality of flat tubes with cooling ribs therebetween. At least one of the heat exchangers has a gradation whereby the one heat exchanger has a portion with a reduced thickness in the flow direction defining a free space, and at least one part of at least one of the other heat exchangers occupies the free space.  
         [0015]     In one form of this aspect of the present invention, the gradation of the at least one heat exchanger is provided in the longitudinal direction of flat tubes.  
         [0016]     In another form of this aspect of the present invention, the at least one heat exchanger is positioned in the lower area of the module.  
         [0017]     In still another form of this aspect of the present invention, the gradation of the at least one heat exchanger is on the front of the module facing the flow direction.  
         [0018]     In yet another form of this aspect of the present invention, the at least one heat exchanger is arranged roughly in a common vertical plane with the radiator.  
         [0019]     In another form of this aspect of the present invention, a condenser for a vehicle air conditioner is provided, wherein the at least one heat exchanger is arranged beneath the radiator, and the condenser and the charge air cooler are arranged in the direction of cooling air flow in front of the radiator.  
         [0020]     In still another form of this aspect of the present invention, the heat exchanger that occupies the free space created by gradation is part of a condenser.  
         [0021]     In yet another form of this aspect of the present invention, the at least one heat exchanger is the charge air cooler.  
         [0022]     In another form of this aspect of the present invention, the at least one heat exchanger has at least two rows of flat tubes with the number of flat tubes in one row being smaller than the number of flat tubes in the other row with the free space being aligned with the one row. In one further form, the cross-sectional size of the flat tubes of one row is the same as the cross-sectional size of the flat tubes of the other row. In another further form, the cross-sectional size of the flat tubes of one row is different from the cross-sectional size of the flat tubes of the other row.  
         [0023]     In still another form of this aspect of the present invention, the atleast one heat exchanger has a single row of flat tube including one group of consecutive flat tubes having a smaller cross-sectional size than others of the flat tubes.  
         [0024]     In another aspect of the present invention, a heat exchanger is provided for use with an arrangement of heat exchangers in a vehicle, including a core having at least one row of longitudinally extending flat tubes with cooling ribs arranged between the tubes, the tubes and ribs being disposed to be traversed by cooling air. The core has a gradation created by one or more of (a) flat tubes arranged in a single row with different cross-sectional sizes, and (b) several rows of flat tubes with a different number of flat tubes. The flat tubes in the rows have the same or different cross-sectional sizes whereby the gradation runs in the longitudinal direction of flat tubes.  
         [0025]     In one form of this aspect of the present invention, the heat exchanger is a charge air cooler. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  is a schematic side view of a first embodiment of an arrangement of heat exchangers according to the present invention;  
         [0027]      FIG. 2  is a view similar to  FIG. 1  of a modified embodiment of an arrangement of heat exchangers according to the present invention;  
         [0028]      FIG. 3  is a side view of one practical example of an arrangement of heat exchangers according to the present invention;  
         [0029]      FIG. 4  is a perspective view of a graded heat exchanger core according to the present invention;  
         [0030]      FIG. 5  is a side view of an alternative embodiment of the graded heat exchanger according to the present invention;  
         [0031]      FIG. 6  is a side view of an arrangement of heat exchangers according to the prior art as previously described; and  
         [0032]      FIG. 7  illustrates a module according to the present invention having an arrangement of heat exchangers for a passenger car. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     In accordance with the present invention, an arrangement of a plurality of heat exchangers (such as, e.g., a radiator, a charge air cooler and a condenser) such as provided for a vehicle and acted upon by cooling air is provided, with the heat exchangers being arranged one behind the other in the flow direction of the cooling air and the arrangement. Such arrangement may be characterized as a module.  
         [0034]     In the embodiments illustrated in  FIGS. 1 and 2 , a radiator  10  is provided with a charge air cooler  14  arranged beneath the radiator  10 . In these embodiments, both the radiator  10  and the charge air cooler  14  include gradations  20  whereby a portion of the height of the radiator  10  and charge air cooler  14  have a smaller depth (front to back) dimension than the rest of the cooler  10 ,  14 .  
         [0035]     A fan  28  is arranged in the flow direction of the cooling air (arrow  24 ) and draws in cooling air (e.g., from the front side of a vehicle when used therewith). The heat exchangers (coolers  10 ,  14 ) may advantageously include a cooling grate or core of flat tubes  30  and cooling ribs (e.g.,  32  in  FIGS. 5 and 7 ) arranged in between through which the cooling air flows such as is well know by those skilled in the art.  
         [0036]     Spatial understanding of the arrangement is facilitated by coordinates illustrated in association with  FIGS. 1 and 2 , wherein T is the depth and runs in the longitudinal direction of, for example, a vehicle when used therewith, which, as is apparent, is the flow direction  24  of the cooling air. H is the vertical direction (i.e., the height) and B is the width direction (perpendicular to the plane of the view of  FIGS. 1 and 2 ).  
         [0037]     In  FIG. 1 , the two rows of flat tubes  30  of the radiator  10  and charge air cooler  14  have a the longitudinal direction lying in the direction of the vehicle width B (i.e., perpendicular to the plane of the Figure). The gradation  20  provided on the radiator  10  and on the charge air cooler  14  extends along the longitudinal direction B of flat tubes  30 .  
         [0038]     In the  FIG. 2  embodiment, the somewhat more frequent practical occurrence is illustrated in which the cooler  14  arranged on the bottom has a greater depth T of its grate than the cooler  10  arranged above it. If a condenser  40  is also included with the heat exchange structure (such as described hereafter), this may then also protrude into the free space  44  created by the gradation  20  so that overall a very compact arrangement is created. With this embodiment, it should also be apparent that the cross-sections of the flat tubes  30  in one row may be much greater than the cross-sections of the flat tubes  30  in the other row. (A row of flat tubes is defined by the fact that the flat tubes  30  are arranged with a spacing, along a common line, facing each other with their broad sides. In between [i.e., in the spacings], the cooling ribs  32  are found, which are usually connected to the broad sides of the flat tubes  30 .) It should be appreciated, however, that the present invention could also be advantageously used with other embodiments having more than two rows of flat tubes in a heat exchanger, with such rows having the same or different cross-sections.  
         [0039]     The condenser  40  illustrated in  FIG. 1  has only a single row of flat tubes  30  having a uniform cross-sectional size (narrow side x wide side), with the dimension in the depth direction T being about 15 mm. The condenser  40  is not depicted in any of the practical examples as a graded heat exchanger in order to avoid the drawbacks of the prior art as previously discussed.  
         [0040]     The advantages of the arrangement for specific applications may be seen by comparing the embodiment of  FIG. 3  with the structure of  FIG. 6  built according to the prior art. The space limitations of the front axle of the vehicle are indicated with reference number  50 , with reference number  52  showing the also invariable position of the bumper of the vehicle. It is apparent from comparison of the two figures that disassembly and assembly of the charge air cooler  14  in the  FIG. 3  embodiment is ensured, whereas that is not possible in the  FIG. 6  structure. During disassembly, the charge air cooler  14  is tilted forward according to the arrow marked on the bottom of  FIG. 3  in order to remove it or install it. Moreover, as also apparent from  FIG. 3 , it is possible to increase the traversable surface of the charge air cooler  14  forward (in previously unused space beneath the bumper  52 ).  FIG. 3  also illustrates one of the fairly large-volume connectors  54  of the charge air cooler  14 , with the graded charge air cooler  14  depicted in  FIG. 3  only by its correspondingly graded tube end plate or bottom  56 . Reference numbers  60  and  62  in this practical embodiment refer to additional coolers such as may be desired for operating media in a particular design.  
         [0041]      FIG. 4  illustrates another design of a graded heat exchanger, specifically a charge air cooler  14 , which may be used with the present invention. The tube bottoms  56  have openings  66 , each of which accommodates one end of a flat tube  30 . Two rows of flat tubes  30  are present in this practical example. The left or first row of the figure has four flat tubes  30  with equally large cross-sectional surface (narrow side x wide side) and an additional four flat tubes  30  beneath it with significantly larger cross-sectional area, but which are also identical to each other. The right or second row in the figure consists merely of four flat tubes  30  whose cross-sections are identical both in terms of area and shape to each other and to the cross-sections of the first four flat tubes  30  of the first row. The gradation  20  achieved by this is apparent and so is the free space  44  created by it. Plates  67  may also be advantageously provided at the top and bottom of each tube row such as is understood by those skilled in the art.  
         [0042]      FIG. 5  shows the tube bottom  56  of another practical example with openings  66  for only one row of flat tubes  30 , with the row consisting of four identical flat tubes  30  and four flat tubes  30  with a larger cross-sectional area. The number of flat tubes per row and the number of rows is guided according to the requirements of the intended use. The tube bottoms  56  are designed with a deformed edge  68  in order to be able to accommodate and fasten a collecting tank (not shown). (It should be pointed out here that the other heat exchangers are also ordinarily equipped with such collecting tanks, even if these are omitted from the figures for illustration purposes.) The free space  44  created by the gradation  20  is marked in  FIG. 5  as a checkered surface.  
         [0043]     The Figures depict embodiments in which the flat tubes  30  are arranged horizontally and in the transverse direction of the vehicle, since such arrangements are more common, especially in passenger car applications. However, it should be understood that arrangements with so-called “falling flow coolers” (i.e., with the flat tubes  30  arranged vertically, in the height direction H) may also advantageously incorporate the present invention.  
         [0044]     Finally,  FIG. 7  illustrates a practical example the present invention in accordance with the embodiment of  FIG. 3 , which structure may in particular be advantageously used in a passenger car. All the heat exchangers  10 , 14 ,  40 ,  60 ,  62  are arranged so that their flat tubes  30  extend in the mentioned transverse direction, with cooling ribs between the tubes  30  (with reference number  32  merely indicating the position of the ribs. The charge air cooler  14  has a gradation  20 , which creates a free space  44 , with part of the supercooling zone  70  of the condenser  40  being situated in this free space  44 . The condensation zone  74  is situated on a vertical plane with the supercooling zone  70 . Partitions  78  are present in the collectors of the condenser  40 , which lead to a coil-like flow through the groups of flat tubes  30  running from the top down. A fan shroud  80 , in which the fan rotates, is situated on the back. It is apparent that very little space is required for the arrangement, especially in the depth direction T.  
         [0045]     It should thus be appreciated that the present invention provides a high-performance arrangement of heat exchangers with optimized space utilization for a vehicle. That is, because at least one of the heat exchangers  14  according to the invention has a graded cross-sectional area and the free space  44  created by the gradation  20  is occupied with at least one part of another heat exchanger, the module has numerous advantages. For example, a complete other heat exchanger, for example an oil cooler, could also be situated in the free space  44  in order to achieve a particularly compact design. Further, the cooling power in the individual heat exchangers is comparatively very good, since the mutual influence and heating of the cooling air by the heat exchanger mounted in front is minimized. Moreover, the design may in many instances permit increasing the gradation spatially in order to increase the cooling capacity or the flow cross-section of the graded heat exchanger so that no detectable deterioration in other heat exchangers on the cooling air side occurs owing to the deep position of the graded heat exchanger.  
         [0046]     It should further be appreciated that disassembly and/or incorporation of the heat exchanger such as may be required in the event of service is made possible by the arrangement of the present invention wherein the gradation is arranged so as to point forward in the vehicle.  
         [0047]     Still further, with the graded heat exchanger arranged in a common vertical plane with a radiator or only slightly offset relative to it (e.g., arranged beneath the radiator, though arrangement above the radiator is not ruled out), the radiator is not adversely affected as strongly by the heat exchanger mounted in front. This is especially true if the graded heat exchanger is a charge air cooler, since the charge air also has very high temperatures that heat the cooling air accordingly.  
         [0048]     Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.