Abstract:
A heat exchanger includes a housing designed to envelop a heat-exchange core bundle. The housing includes an opening that allows the heat-exchange core bundle to be housed inside the housing. The heat-exchange core bundle includes a first end designed to plug the opening of the housing when the heat-exchange core bundle is inserted inside the housing, and a second end of the heat-exchange core bundle, opposite the first end, with at least one fastening means in the form of a peg, for fastening the second end of the heat-exchange core bundle to the wall of the housing.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a heat exchanger, for example a heat exchanger intended for a motor vehicle. More specifically, the invention relates to a heat exchanger that allows an exchange between a first fluid and a second fluid, in which the first fluid is, for example, a gazeous fluid such as air and the second is a liquid fluid such as water. The heat exchanger, according to the present invention, is particularly suited to use for cooling charge air. 
       PRIOR ART 
       [0002]    Nowadays, motor vehicle combustion engines are often charged with compressed air so as to improve the performance of these engines. This compressed air is often known by the name of “charge air”. The compressed air is obtained by using a compressor driven by the exhaust gases. As a result, the compression of the air has the effect of heating the air. Therefore it proves necessary to cool the compressed air before it is introduced into the engine, so as to lower the temperature of the air before it is introduced into a cylinder of the engine. 
         [0003]    To cool the compressed air, it is known practice to use a heat exchanger comprising a heat-exchange core bundle made up of an assembly of plates, positioned one on top of another and in combination forming a canal for guiding a fluid such as a liquid from an inlet to an outlet. In order to improve the exchange of heat, the assembly of plates is supplemented by corrugated interlayers. 
         [0004]    The heat-exchange core bundle is positioned inside a casing or housing. This housing is provided with an inlet and an outlet for the second fluid that is to be cooled, such as the air, and is designed to guide the air from an inlet to an outlet. The housing acts as a header enveloping said heat-exchange core bundle and allowing the admission and regulation of the charge air. Such a housing is, for example, molded from a material such as aluminum or plastic. 
         [0005]    In practice, walls of the housings are relatively thin and relatively flexible. Thus, when the housings are in use, the volume of said housings may increase with the increase in pressure and temperature within the housings. 
         [0006]    The housing of a heat exchanger according to the prior art is provided with an opening allowing the heat-exchange core bundle to be introduced into the housing. For this type of application, the heat-exchange core bundle is, in theory, connected to a closure component such as a cover. The cover allows the assembly of plates and of corrugated interlayers to be connected and allows that assembly to be fixed against said connection plate. The cover is provided with canals for introducing the liquid fluid, such as a liquid, into the heat exchanger and removing it therefrom. The cover fixed to the exchange core bundle performs a function of closing the opening that allows the heat exchanger to be introduced. Thus, the heat-exchange core bundle is first of all enveloped or surrounded by the walls of the housing and is then surrounded by the cover. 
         [0007]    In its position of use, the cover, to which the heat-exchange core bundle is fixed, is theoretically positioned in an essentially horizontal position above said heat-exchange core bundle. In other words, the heat-exchange core bundle is suspended from the cover. 
         [0008]    Heat exchangers known from the prior art have a number of disadvantages. First, the connection between the housing and the cover is very fragile and needs to withstand the high pressure and high temperatures all present inside the heat exchanger. In addition, the walls of the housing may, during normal use of the heat exchanger, deform under the pressure of the hot air present inside said heat exchanger. This deformation, which is constant through the use of the heat exchanger, may lead to premature wear of the material used in the manufacture of the housing. This then may impair the reliability of the housing. 
         [0009]    Insofar as the heat-exchange core bundle is suspended from the cover, the heat-exchange core bundle may exhibit pendular movements under the influence of vibrations caused by the operation of the engine of the vehicle with which the heat exchanger is used. The repeated nature of these pendular movements, especially if a resonance effect is present, may have a detrimental influence on the reliability of the heat exchanger. 
         [0010]    Nowadays, the volume set aside for heat exchangers and components thereof within the motor vehicles has a tendency to be reduced so that other devices necessary for the operation of said motor vehicles can be installed. Moreover, it is important to reduce the weight of all the components of a vehicle, including that of the heat exchanger. It is therefore important to develop heat exchangers that are compact and allow a relatively lightweight construction. 
       SUBJECT OF THE INVENTION 
       [0011]    The heat exchanger according to the present invention seeks to overcome the disadvantages of the heat exchangers as disclosed in the prior art by proposing a new design regarding how a heat-exchange core bundle is fixed inside the housing of a heat exchanger. 
         [0012]    To this end, the present invention relates to a heat exchanger comprising a housing designed to envelop a heat-exchange core bundle, said housing being provided with an opening that allows said heat-exchange core bundle to be housed inside said housing, and with a heat-exchange core bundle, said heat-exchange core bundle comprising a first end designed to plug the opening of the housing when the heat-exchange core bundle is inserted inside said housing, characterized in that a second end of the heat-exchange core bundle, opposite said first end, is provided with at least one fastening means in the form of a peg, for fastening said second end of the heat-exchange core bundle to the wall of the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The objects, subject matter and features of the present invention and the advantages thereof will become more clearly apparent from reading the following description of some preferred embodiments of a heat exchanger according to the invention, with reference to the drawings in which: 
           [0014]      FIG. 1  is a perspective view of a heat exchanger within a housing according to a first embodiment of the present invention, with an exterior part of the housing removed in order to show the components present inside said exchanger, by way of example; 
           [0015]      FIG. 2  depicts in detail how the heat-exchange core bundle is fixed to the walls of the heat-exchanger housing, by way of example; 
           [0016]      FIG. 3  schematically shows the fixing of the heat-exchange core bundle to the walls of the housing of the heat exchanger using a fastening means fixed using “snap-fits” to the bottom plate of the heat-exchange core bundle, by way of example; 
           [0017]      FIG. 4  schematically depicts the fixing of a heat-exchange core bundle to the walls of the housing of the heat exchanger using a component made of plastic, before the deformation thereof, by way of example; 
           [0018]      FIG. 5  shows the fixing of the heat-exchange core bundle to the walls of the housing of the heat exchanger using a fastener made of plastic, after a certain amount of heat has been applied that has enabled the shape of said fastener to be modified, by way of example; 
           [0019]      FIG. 6  depicts the fixing of the heat-exchange core bundle to the walls of the housing of the heat exchanger using a fixing comprising “male” and “female” fasteners, by way of example. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0020]      FIG. 1  is a perspective view of one embodiment of a heat exchanger  1  according to the present invention. Part of the outside of the heat exchanger  1  has been removed in order to show the inside of said heat exchanger. 
         [0021]    The heat exchanger as shown in  FIG. 1  is particularly suited to use in the automotive industry as a charge air cooler (CAC) of a combustion engine. The heat exchanger  1  is able to cool the charge air by exchange of heat with a first fluid, such as the outside air, or a liquid such as, for example, the engine coolant, thus forming an exchanger of the air/air or liquid/air type. 
         [0022]    First of all, the heat exchanger  1  comprises an intake manifold  2  (the English expression “intake manifold” is often used by those skilled in the art). The intake manifold  2  is fixed to the cylinder head of the combustion chamber of the engine, namely to the entry to the cylinder. Depending on the engine speed, the air may be cooled completely or partially, or the air may remain uncooled. The intake manifold  2  is connected to a housing or housing  3 . This housing  3  forms a wrapper for a heat-exchange core bundle  4  that lies inside said housing  3 . 
         [0023]    The heat-exchange core bundle  4 , according to the present invention, is positioned inside a housing  3 . This housing  3  is provided with an inlet and with an outlet for a gaseous first fluid and is designed to guide said first fluid from an inlet to an outlet. 
         [0024]    The heat exchanger  1  according to the present invention comprises a heat-exchange core bundle  4  made up of an assembly of plates positioned on one another and in combination forming a canal for guiding a liquid second fluid which is used for cooling the gaseous first fluid, from an inlet to an outlet. In order to improve the exchange of heat, the assembly of plates is supplemented by corrugated interlayers. 
         [0025]    In known operation, a first fluid such as air passes over the outside of the heat-exchange core bundle  4  and a second fluid, such as, for example, the water from the coolant circuit, circulates inside the heat-exchange core bundle  4  and thus allows the air to be cooled. 
         [0026]    The heat-exchange core bundle  4  is formed of an assembly of pressed plates, also referred to as “half-layers”. However, the invention also applies to other types of core bundle, and notably to core bundles comprising tubes and fins. The heat-exchange core bundle  4 , as shown in  FIG. 2 , is formed of a stack of pressed plates arranged in pairs, each produced to be identical. Only the two end plates that form the top end and the bottom end of the heat-exchange core bundle  4 , as shown in  FIG. 1 , differ in shape in comparison with the stacked pressed plates. 
         [0027]    Each pressed plate has a rectangular shape and comprises a substantially planar bottom wall bounded by a rectangular peripheral rim, which is raised in relation to the bottom wall to form a shallow pan. Each pair of pressed plates delimits a chamber. The use of a plate of this type is known to those skilled in the art. 
         [0028]    The pressed plates form the heat-exchange core bundle  4  and are arranged in pairs. The respective bossing of one pressed plate belonging to one pair is in communication with the respective bossing of an adjacent pressed plate belonging to part of the next pressed plates. 
         [0029]    The heat-exchange core bundle  4  comprises corrugated interlayers  5 , as shown in  FIG. 2 , arranged between adjacent pressed plate pairs. The various pressed plates and the corrugated interlayers  5  are, according to a known technique, assembled using a brazing process. After assembly, the heat-exchange core bundle  4  delimits first canals for the gas that is to be cooled, in which canals the corrugated interlayers  5  are present, and second canals for the circulation of the coolant, obtained using plates. 
         [0030]    All of the constituent parts of the heat-exchange core bundle  4 , the pressed plates, the corrugated interlayers  5 , the intake manifolds and coolant inlet and outlet are advantageously made of an aluminum alloy, assembled with one another and brazed in a single operation in a brazing furnace. 
         [0031]    As shown in  FIG. 1 , the upper part of the heat-exchange core bundle  4  is fixed to a closure component  6  such as a plate or a cover  6 . The cover  6  performs several functions. One of the functions is to allow the coolant to enter and leave the cover via tubes arranged on the cover  6 . Moreover, the cover  6  forms the component that closes the housing  3 . Thus, when the heat exchanger  1  is assembled, the heat-exchange core bundle  4  is enveloped firstly by the walls formed by the housing  3  and secondly by the cover  6 . 
         [0032]    The heat exchanger  1  according to the present invention is provided with fasteners  21 ,  22  and  23  which are fixed to the lower end of the heat-exchange core bundle  4 . The fasteners  21 ,  22  and  23  are designed to pass through the wall of the housing  3  and to be fixed to said wall of the housing  3 , using any suitable means. 
         [0033]    When the fasteners  21 ,  22  and  23  are fixed to the wall of the housing  3 , a number of technical effects are achieved. Notably, the rigidity of the heat exchanger  1  increases. In addition, the set of fasteners  21 ,  22  and  23  forms a homogeneous and unified structure when the underside of the heat-exchange core bundle  4  is fixed to the walls of the housing  3 . 
         [0034]    Thus, when the heat-exchange core bundle  4  is fixed to the walls of the housing  3 , said walls of the housing  3  can no longer undergo deformation as a result of the action of the hot and pressurized air present inside said housing  3 . Deformation is therefore limited during normal use of a heat exchanger  1  according to the present invention. Moreover, when the underside of the heat-exchange core bundle  4  is fixed to the walls of the housing  3 , this heat-exchange core bundle  4  can no longer effect a pendular movement. In other words, the detrimental wearing effect caused by the pendular movements is therefore eliminated. 
         [0035]      FIG. 2  depicts detail of a first embodiment of the fastener  21 .  FIG. 2  shows that the walls  31  of the housing  3  comprise a break through which the fastener  21  can pass. The fastener  21  is fixed to the bottom end of a heat-exchange core bundle using a brazing process. That means that during assembly of the heat-exchange core bundle  4 , a single operation, performed in a brazing furnace, allows a heat-exchange core bundle  4  to be assembled and allows the fasteners  21 ,  22  and  23  to be fixed to the bottom end of the heat-exchange core bundle. 
         [0036]    The fastener  21  may, for example, be fixed to the walls  31  of the housing  3  using a nut (not shown). 
         [0037]      FIG. 3  shows a second embodiment of the fixing of a fastener  41 . In this embodiment, the fastener  41  is fixed to the bottom end of the heat-exchange core bundle  4  using an elastic means of assembly also known by the English name of “snap-fit” assembly. 
         [0038]      FIG. 4  schematically depicts a third embodiment of the fixing of a fastener  51  to the bottom end of a heat-exchange core bundle  4 . The fastener  51  is made of plastic able to deform under the influence of a source of heat. As shown in  FIG. 4 , when the fastener  51  has passed through the wall  31  of the housing  3  shown in  FIG. 1 , a certain amount of heat, combined with a certain amount of pressure, can be used to deform the fastener  51  and thus fix the bottom part of the heat exchanger  4  to the wall  31  of the housing  3 . 
         [0039]    Another embodiment of a fastener  61  is shown in  FIG. 6 . The “female” first component may be fixed or assembled, for example using a brazing process, on the bottom end of the heat exchanger  4 . After assembly, this fastener  61  may be fixed to the wall  31  of the housing  3  using a screw  62  that forms the “male” component of the fixing  25 . 
         [0040]    When the heat exchanger  1  according to the present invention is in use, it is important for the wrapper situated around the heat-exchange core bundle  4  to be fluidtight. Thus, the fixings of the bottom part of the heat-exchange core bundle  4  to the wall  31  of the housing  3  need to be made with care. In order to ensure the fluidtightness of the passage of the fasteners  21 ,  22 ,  23 ,  41 ,  51  and  61 , sealing elements such as sealing rings need to be provided. 
         [0041]    Within the embodiments described hereinabove it has been indicated that the fasteners  21 ,  22 ,  23 ,  61  may be fixed to the bottom end of the heat-exchange core bundle  4  using a brazing process. Any other method for fixing fasteners may be envisioned; for example using a suitable adhesive means. 
         [0042]      FIG. 5  shows the fixing of the heat-exchange core bundle to the walls of the housing of the heat exchanger using a fastener made of plastic, after a certain amount of heat has been applied that has allowed the shape of said fastener to be modified. 
         [0043]      FIG. 6  depicts the fixing of the heat-exchange core bundle to the walls of the housing of the heat exchanger using a fixing comprising “male” and “female” fasteners.