Abstract:
The invention relates to an operating fluid container for a motor vehicle, said container including a container body which is assembled from at least two injection-molded shells of thermoplastic plastics material which are complementary to each other. The shells are provided in each case with integrally molded structures which extend into the free container volume in such a manner that they bring about a restriction of a fluid surge created, for instance, in the container. At least some of the structures on each of the two shells are welded together at least in part or in a punctiform manner approximately in the joining plane of the container.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase 371 application of PCT application no. PCT/EP2012/003919 filed Sep. 20, 2012, which claims priority to German application no. 10 2011 115 384.9 filed Oct. 10, 2011 which are hereby incorporated by reference. 
     FIELD 
     The invention relates to an operating fluid container for a motor vehicle. 
     SUMMARY 
     The term operating fluid container within the meaning of the present application can refer either to a so-called secondary fluid container or to a fuel container. Those operating fluid containers which accommodate operating fluids that are not necessary for the direct operation of an internal combustion engine are referred to as secondary fluid containers. In this connection, suitable operating fluid containers, for example, are windscreen wash containers, oil containers, secondary oil containers, coolant fluid containers for air-conditioning systems or so-called SCR containers. SCR containers are containers which accommodate a urea solution for catalytic exhaust gas reduction. Such containers play an increasing role in the course of emission control in the case of diesel vehicles. As the urea solution develops unpleasant odours in particular in contact with atmospheric oxygen, the so-called servicing capability of the container also plays an increasing role, in particular in the case of containers in passenger cars, the servicing and the refilling of the containers should be carried out where possible by service personnel at the workshop. Accordingly, the container volumes are designed in accordance with the inspection interval usual nowadays. As the container volumes increase, the development of the container has to be designed according to stability criteria and with regard to sloshing and surging noises created for instance as a result of movements of the fluid induced by the dynamics of the vehicle movement. 
     The operating fluid container according to the present invention can obviously also be used as a fuel container with the fittings for the conveying of the fuel and with means for ventilation and aeration usually provided for this purpose. 
     The object underlying the invention is to provide for a motor vehicle an operating fluid container which is improved in particular with regard to the stability and the development of surge noises in the case of larger fluid volumes. 
     The object is achieved by an operating fluid container for a motor vehicle, said container including a container body which is assembled from at least two shells of thermoplastic plastics material which are complementary to each, wherein the shells in each case have integrally moulded structures which extend into the free container volume in such a manner that they bring about a restriction of a fluid surge created, for instance, in the container, wherein at least some of the structures on each of the two shells are welded together at least in part approximately in the joining plane of the container. 
     The operating fluid container according to the invention is preferably realized as an injection-moulded container of thermoplastic plastics material. In an advantageous manner, two half shells obtained by injection-moulding are welded together in an at least circumferential manner to form a closed container. 
     The advantage of producing the container using an injection-moulding method is that the shells can be provided in each case relatively simply with integrally moulded structures. As an alternative to this, it is also possible for the container according to the invention to be assembled from deep-drawn half shells of thermoplastic plastics material. 
     It is provided according to the invention, in addition to the circumferential edge-side welding of the half shells, to reinforce the same at least in a punctiform manner by way of structures which extend right into the free container volume, by way of which structures then, on the one hand, a division of the free container volume into compartments which are separated more or less from each other is achieved and, on the other hand, the stability of the container is significantly increased. The welding together of the structures which extend right into the container bestows a higher level of compressive strength on the container overall, in particular a higher carrying capacity in the direction of gravity as a result of greater amounts of fluid contained in the container. 
     In the case of an expedient embodiment of the operating fluid container according to the invention, it is provided that in each case one integrally moulded surge wall element is provided on at least two shells, wherein the surge wall elements of two complementary shells are welded together in the joining plane at least in a punctiform manner. The term joining plane within the meaning of the present invention does not necessarily refer to a single two-dimensional plane, rather the joining plane can be offset or the shells can have several joining planes which can also extend diagonally, where applicable, with reference to the position of installation. 
     In this way, a reduction of sloshing movements of the fluid straying in the container can be achieved in an effective manner without this being implemented with an increase in weight caused by additional fittings in the container. In addition, this also leads, as already mentioned above, to a significant increase in stability. 
     In order to enable rapid levelling inside different regions of the container and to enable rapid fluid removal from the container without significant flow resistance, it is advantageous when the surge wall elements are provided at least in part with openings. 
     The surge wall elements do not necessarily have to merge into the relevant container wall in a linear manner, rather said surge wall elements can be provided in the regions abutting against the container wall with openings which form bridges. As an alternative to this, the surge wall elements can be connected to the container wall by means of individual webs such that said surge wall elements have a certain reversible deformability at the fluid impact. 
     In the case of a preferred variant of the operating fluid container according to the invention, it is provided that two surge wall elements of complementary shells, said surge wall elements adjoining each other, form flow passages between each other. At least one of the surge wall elements can be provided additionally, as mentioned above, with openings. 
     In the case of a particularly preferred embodiment of the operating fluid container according to the invention, it is provided that the surge wall elements of different shells intersect in their projection onto the joining plane and abut against each other only in the region of their intersecting points. 
     In this way, flow passages are produced between the regions of the container which are formed by the surge wall elements and which extend transversely with respect to a wave propagation anticipated in the fluid, that is to say approximately vertically in the position of installation of the container. 
     It is particularly advantageous when the surge wall elements of different shells are welded together in the joining plane in the region of their intersecting points. 
     In addition to this or as an alternative, the shells can have in each case at least one dome which extends into the container volume, the shells being supported in relation to each other by means of the domes. Said domes can be welded to each other for example at the end face and in each case can form pillars for surge fittings extending between the domes. 
     In the case of an expedient development of the operating fluid container according to the invention, it is provided that the shells are centred with respect to each other by means of at least two domes. 
     The domes, in this case, ensure a defined spacing between the large-area container wall regions with respect to each other, stabilize the container in the case of possible pressure fluctuations in the container and serve as fastening/anchoring points for surge fittings which are to be provided in the container and which can be integrally moulded or, however, can have been fastened on the domes prior to joining the half shells together. Over and above this, said domes fulfil the function of centering the shells with respect to each other during the joining operation, that is to say when welding the shells. 
     The domes can be realized, for example, in each case as inversions of the container wall. Stabilization of the container by means of supports/pillars/domes can be achieved in this way using the smallest possible amount of material. The domes do not necessarily have to be peg-shaped, rather they can have other geometries. Neither do they have to necessarily be realized as inversions of the container, rather support crosses or angular support pillars which are injected onto the container inner wall can also be provided in place of domes. 
     In the case of a particularly advantageous embodiment of the operating fluid container according to the invention, it is provided that at least one cable and/or line duct is provided in at least one surge wall profile. To this end, for instance keyhole-shaped openings can be provided, for example, in the surge wall profiles, through which, during the assembly of the shells, cables and/or lines can be clamped or pressed into position. The relevant opening in the surge wall profile is closed when adding the complementary shells to the container such that a defined position of the lines and/or cables is ensured inside the container volume. 
     The container wall can be provided with reinforcement structures such as ribs, honeycombs or the like at least in sections. 
     Over and above this, however, the container walls can also be clad with elastic mats. Such an arrangement serves for absorbing the transmission of structure-borne noise. These types of mats can be arranged, for example, by bonding, that is to say by interposing an adhesive on the container inner wall. Mat-like structures can be injected onto the inner wall of the container as an alternative. 
     In the case of a very advantageous variant of the operating fluid container, at least one flexible mat, which is preferably wavable and can float as a result of the fluid dynamics, that is to say can follow a wave movement of the fluid at least in a restricted manner, extends inside the container volume. 
     Such a flexible mat can extend approximately parallel to the joining plane of the container. For example, a surge mat can be clamped between several domes in such a manner and can be penetrated by said domes in such a manner that it can be lifted in relation to the domes as a result of the fluid dynamics. 
     In the case of an expedient development of the operating fluid container according to the invention, it is provided that that the shells are welded together by means of a circumferential flange, wherein the flange is realized as an undercut collecting edge, which makes it possible, for example, to mount heat shields, insulating elements or the like. 
     To reduce the propagation of structure-borne noise caused by surge noises generated by the fluid in the container, the container can be provided, for example at the edge, with fastening eyelets/fastening eyes, into which elastic bushes are inserted. The elastic bushes can be integrally injection-moulded, for example. As an alternative to this, the eyelets/eyes can be injected around by an elastic material, for example a thermoplastic elastomer. 
    
    
     
       FIGURES 
       The invention is explained below by way of an exemplary embodiment shown in the drawings, in which: 
         FIG. 1  shows a perspective view of a container according to the invention, 
         FIG. 2  shows a side view of the container according to the invention, 
         FIG. 3A  shows a cross section through the top shell of the container according to the invention, 
         FIG. 3B  shows a cross section through the bottom shell of the container according to the invention, 
         FIG. 4  shows a view along the lines IV-IV in  FIG. 3B , 
         FIGS. 5 and 6  show sectional views of the circumferential container edge, 
         FIG. 7  shows a further part sectional view of the container according to the invention, 
         FIG. 8  shows a perspective view of the detail of detail VIII in  FIG. 7 , 
         FIG. 9  shows a view of the detail of the container wall (position IX in  FIG. 7 ) and 
         FIG. 10  shows a further view of the detail of the container wall according to position X in  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     The operating fluid container  1  according to the invention is provided essentially as a container for the accommodation of a fluid urea solution for the catalytic reduction of exhaust gases in diesel vehicles. As already mentioned above, the operating fluid container according to the invention could also certainly be realized as a fuel container. 
     Said operating fluid container consists essentially of thermoplastic plastics material, comprising two shells  2   a ,  2   b  which have been produced in each case by means of injection-moulding and have been welded together along a circumferential flange  3  to form a closed container. 
     The operating fluid container  1  includes, for example, a filler neck  4  for tapping lines as well as a connection nipple  5  for operating and refuelling venting. 
     The bottom shell  2   b  of the operating fluid container  1  is provided with a bottom opening  6  for the insertion of a conveying module (not shown) with further operating components. 
     As can be seen in particular when looking at  FIGS. 3 and 4  together, at least one surge wall element  7  is integrally moulded on each of the shells  2   a ,  2   b . The surge wall element provided in the bottom shell  2   b  is realized, for example, extending in the shape of a wavy line, whereas the surge wall element  7  in the top shell  2   a  extends in an approximately straight line into the volume of the operating fluid container  1 . The surge wall elements can obviously form different geometries, e.g. can be arranged extending in a zigzag or curved manner. The surge wall elements  7  are both realized so as to close off approximately flush with the joining plane  8  which is clamped by the circumferential flange  3 . In the case of the exemplary embodiment shown, the joining plane  8  extends between the shells  2   a ,  2   b  in an approximately horizontal and level manner. Obviously, said joining plane  8  can be offset with reference to a horizontal installation position. 
     With the shells  2   a ,  2   b  assembled, the surge wall elements  7  of both shells  2   a ,  2   b  abut against each other in the joining plane  8  such that they form two compartments  9   a ,  9   b  inside the operating fuel container  1 . A fluid exchange between the compartments can be effected, on the one hand, through openings  10  in the surge wall elements  7 , on the other hand, the surge wall elements  7  do not extend completely between two diametrically opposite points of the flange  3  such that lateral ducts  11 , which also enable a fluid exchange between the compartments  9   a ,  9   b , are created. 
     Over and above this, the surge wall elements  7  of two shells  2   a ,  2   b , as can be seen in particular in  FIG. 8 , are arranged in the joining plane  8  so as to abut against each other only in a punctiform manner such that window-like openings  13 , which extend in the joining plane  8 , are created between the weld points provided there, said openings enabling fluid exchange and passage transversely with respect to the joining direction of the shells  2   a ,  2   b , that is to say in the installation position approximately vertically and transversely with respect to the surge movement of the fluid. 
     Reference is once again made to  FIG. 3 , in which the surge wall element  7  provided in the top shell  2   a  can be seen. Said surge wall element  7  is injection-moulded onto the shell  2   a  by means of material bridges  14 . On the one hand, the openings  10  created thereby enable fluid exchange, on the other hand as a result the surge wall element  7 , with reference to the shell  2   a , obtains a certain flexibility which is desirable for reasons of the propagation of structure-borne noise as well as for reasons of the stability of the operating fluid container  1 . 
     As can also be seen from  FIG. 3 , the surge wall element  7  provided in the top shell  2   a  is provided with keyhole-shaped receiving means  15  for lines and/or cables. A cable or a line can be pressed into the receiving means  15  through the insertion slot  16  prior to fitting the shells  2   a ,  2   b  together, as is shown by implication. When the shells  2   a ,  2   b  are joined together, the relevant line is held in a captive manner in the receiving means  15  and is securely fixed in position for the service life of the operating fluid container  1 . 
     Reference is now made to  FIGS. 5 and 6 , in which an enlarged and sectioned representation of the flange  3  of the shells  2   a ,  2   b  is shown. 
     As can be seen from the drawing, the flange  3  of the shells  2   a ,  2   b  is realized as an undercut collecting edge, in which region the shells  2   a ,  2   b  are welded in a circumferential manner. Said undercut collecting edge enables the flange  3  to be encompassed by means of retaining brackets or the like. In this way, for example, the bottom shell  2   b  can be underpinned by means of a heat shield (not shown). 
     As an alternative or in addition to this, it can be provided that the shells  2   a ,  2   b  are encompassed on the flange  3  by means of tightening straps. The flange  3  can also serve for the purpose of providing outer insulation on the operating fluid container  1 . 
     In addition to the surge wall elements  7  described beforehand, other structures can be provided in the free volume of the operating fluid container  1  for preventing sloshing and surging noises. 
     For example, a honeycomb structure (not shown) can be arranged in the operating fluid container  1 . 
     As an alternative to this, it can be provided that free volumes of the operating fluid container are filled out with an open-pored foam body or another sponge-like structure. 
     Additional stabilizing of the operating fluid container  1  is achieved by column-shaped domes  17  which have been obtained in each case by inversions of the shells  2   a ,  2   b.    
     As can be seen in particular from  FIG. 7 , the domes  17  are arranged in the shells  2   a ,  2   b  such that they abut against each other when the shells  2   a ,  2   b  are joined together. This can be effected in an obtuse manner at the end face, the domes then being welded together in the region. As an alternative to this, it is possible to realize the domes  17  in each case with profiled end faces which interlock, for example, according to the press-stud principle and centre the shells  2   a ,  2   b  in relation to each other in order to bring about both an alignment and a supporting of the shells  2   a ,  2   b  or of their larger wall regions in relation to each other. 
     In the case of the exemplary embodiment shown, only one dome  17  is provided in each of the shells  2   a ,  2   b  such that there is only one strut/support/column in the operating fluid container. 
     It is obviously possible for several domes  17 , which serve, for example, for the securing of a flexible surge mat  18 , to be provided in each case in the shells  2   a ,  2   b . Said surge mat  18  is shown only by implication in  FIG. 7 . The surge mat  18  can be provided, for example, with several openings which are approximately annulus-shaped and serve as fastening eyes. Said openings can be penetrated by several domes  17  which then together serve as fastening columns for the surge mat  18  in such a manner that the surge mat  18  can be lifted by the wave movement of the fluid. 
     The surge mat  18  can be realized both as a closed mat and as a grid/network or sieve structure. 
     The operating fluid container  1  according to the invention is provided in an advantageous manner in sections with reinforcements of the container wall thereof. For example, the inner surface of the container wall can be realized as a honeycomb. Such a honeycomb is shown, for example, in  FIG. 9 . 
     As an alternative to this or in addition, the inner wall of the container can be provided with ribs for reinforcement, as is shown, for example, by implication in  FIG. 10 . 
     As can be seen from  FIG. 1 , both in the top shell  2   a  and in the bottom shell  2   b  the operating fluid container  1  includes fastening tabs  19  with fastening bores  20 , which serve for connection to the bodywork. Elastomer bushes can be inserted into the fastening bores  20  for decoupling the operating fluid container  1  with reference to the bodywork. Such fastening bores  20  can also be injection-moulded. 
     LIST OF REFERENCES 
     
         
           1  Operating fluid container 
           2   a ,  2   b  Shells 
           3  Flange 
           4  Filler neck 
           5  Connection nipple 
           6  Bottom opening 
           7  Surge wall element 
           8  Joining plane 
           9   a ,  9   b  Compartments 
           10  Openings 
           11  Lateral ducts 
           12  Weld points 
           13  Openings 
           14  Material bridges 
           15  Receiving means 
           16  Insertion slot 
           17  Dome 
           18  Surge mat 
           19  Fastening tabs 
           20  Fastening bores