Abstract:
A motor vehicle having at least one sound generating system for generating an artificial engine noise, which has at least one electrically controllable vibration exciter, wherein the vibration exciter is fastened to a component that is acoustically and/or vibrationally decoupled from a body of the motor vehicle. The component is retained on the motor vehicle by a retaining device, which covers the component at least to a large extent. By means of this measure, the acoustic properties of the sound-generating system can be significantly improved.

Description:
[0001]    This nonprovisional application is a continuation of International Application No. PCT/EP2013/071324 which was filed on Oct. 11, 2013 and which claims priority to German Patent Application No. 10 2012 025 584.5, which was filed in Germany on Oct. 12, 2012, and to German Patent Application No. 10 2012 025 585.3, which was filed in Germany on Oct. 12, 2012, and all of which are herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a motor vehicle having at least one sound-generating system for generating an artificial engine noise and to a support structure for a motor vehicle. 
         [0004]    2. Description of the Background Art 
         [0005]    Motor vehicles, which can also be driven at least at times without an internal combustion engine, especially hybrid, electric, and fuel cell vehicles, are very quiet when the propulsion occurs solely without a combustion engine. This applies especially at a slow speed, for example, in a residential area. This results in an increased risk of accidents for pedestrians or cyclists who usually expect the loud noise of a combustion engine when a motor vehicle approaches. 
         [0006]    For this reason, there are legal requirements worldwide, or they are being prepared, that call for exterior noise for such “silent” motor vehicles in the range of 0 to about 50 km/h, because the noise produced thus far by combustion engines can be absent at least at times. 
         [0007]    A motor vehicle is known from DE 10 2010 005 138 A1. The sound-generating system in this case consists of a vibration generator, disposed on an exhaust muffler of an exhaust gas system of the motor vehicle. 
         [0008]    Such a solution is not optimal with respect to sound radiation or acoustic properties and thus to the warning effect for pedestrians and the like. 
         [0009]    In addition, the long-term stability of such a solution is arguable on account of the enormous heat generation in the case of direct contact with such an exhaust gas unit and the direct, unprotected proximity of the ground. 
       SUMMARY OF THE INVENTION 
       [0010]    It is therefore an object of the present invention to provide an improved motor vehicle with respect to at least the acoustic properties of the sound-generating system. 
         [0011]    In an embodiment, the invention is based on a motor vehicle having at least one sound-generating system for generating an artificial engine noise, which has at least one electrically controllable vibration exciter, whereby the vibration exciter is fastened to a component that is acoustically and/or vibrationally decoupled from the vehicle body. 
         [0012]    It is provided according to an embodiment of the invention that the component for its part is retained on the motor vehicle by a retaining device, which covers the component at least to a large extent. 
         [0013]    The acoustic properties of the sound-generating system can be improved considerably by this measure. In particular, surprisingly the cutoff frequency of the sound-generating system at which loss of sound pressure occurs can be shifted thereby considerably toward lower frequencies. An embodiment provides that the vibration exciter is fastened to such a side of the component that is covered at least to a large extent by the retaining device. This results in better protection of the vibration exciter from environmental effects and thereby in an increase in the functional reliability and long-term stability. 
         [0014]    According to an embodiment, it is provided that the retaining device has an opening, which is located in the area of the vibration exciter and surrounds the exciter. Because of this, part of the vibration exciter in the case of vibrations can project unimpeded through the opening, which enables a very compact construction of the retaining device. The opening can be selected as approximately circular and as small as possible, so that it surrounds the vibration exciter in the immediate vicinity, preferably approximately concentrically. 
         [0015]    According to an embodiment of the invention, the opening can be closed by an air-permeable and flexible material. The material can be made, for example, foam-like. As a result, despite further improvement of the acoustic properties the mobility of the vibration exciter remains unimpeded. 
         [0016]    Optimal results with respect to acoustic properties can be achieved when the component is completely covered by the retaining device. 
         [0017]    The retaining device can be formed as a single piece. As a result, advantages can be achieved with respect to fabrication and installation costs and also with respect to long-term stability. 
         [0018]    The component can be formed flat. Flat here can be, for example, that the surface extension of the component is many times greater than its thickness. The component can be caused to vibrate especially well due to the flat design thereof. Moreover, this type of embodiment contributes to a compact construction. 
         [0019]    According to an embodiment, the component can have tongue-like elements, integrally connected thereto. The component can be fastened to the retaining device by the tongue-like elements most effectively in a vibrationally decoupled manner. 
         [0020]    To improve still further the acoustic and/or vibrational decoupling of the component from the body, the component can be fastened acoustically and/or vibrationally decoupled to the retaining device and the device is fastened again acoustically and/or vibrationally decoupled to a different component of the motor vehicle. The different component can be, for example, a hood or trunk lid. 
         [0021]    The installation is simplified, if the retaining device has a depression into which the component retaining the vibration exciter is inserted. 
         [0022]    To facilitate the integration of the component into the motor vehicle in tight spaces as well, it is proposed to give the component an approximately circular shape in outline. 
         [0023]    A further embodiment of the invention provides for the fastening of the component to such a support structure on which at least one radiator as well is retained in any event. Such a support structure, which is installed in the front end of a motor vehicle, is used for installing a plurality of individual components, such as, for example, a radiator and a fan, and thus represents an integration platform for a plurality of individual components in the front end. This type of support structure is therefore also sometimes called a “mounting support” or “structural support.” It can include, for example, of plastic, aluminum, or steel and is also produced increasingly as a hybrid component of said materials (PP or PR plastic/steel). 
         [0024]    Because such a support structure is present anyway in the front end, a sound-generating system can be provided cost-effectively by the solution of the invention and in the case of a small space requirement. Moreover, optimal sound radiation in the direction of travel is possible because of the positioning in the front end, namely, in the immediate vicinity of the radiator. 
         [0025]    A further embodiment of the invention provides that the component can be fastened acoustically and/or vibrationally decoupled to an engine shield. 
         [0026]    To reduce the sound emission downward (in the direction of the ground or roadway), an engine shield therefore can have a wall, which can be connected below the engine to the body, oriented approximately horizontally, and positioned approximately at the level of the underbody and connected to it at that point. In addition or alternatively, to reduce the lateral sound radiation, approximately vertically arranged walls can also be part or the object of an engine shield. A wall arranged above the engine can also be found in addition at times, so that the engine shield is configured nearly in the shape of a capsule. It is also conceivable and often typical that the engine shield comprises only a bottom wall. 
         [0027]    Therefore an engine shield wall already present in any case can be used to fasten the sound-generating system cost-effectively. Because of the naturally extensive walls of an engine shield, the component carrying the vibration exciter can also be larger, which is favorable for generating lower frequencies in the range of 200 Hz. 
         [0028]    The positioning of the sound-generating system in the vicinity of the engine promotes a sound radiation that is perceived as natural and coming from the engine. 
         [0029]    According to an embodiment of the invention, the component can be fastened to a bottom wall of the engine shield. It usually has an especially large surface extension with the already mentioned advantages for the component supporting the vibration exciter. 
         [0030]    It is also possible alternatively or in addition, however, to fasten the component to an upper wall of the engine shield. 
         [0031]    A support structure for a motor vehicle is also provided. The support structure can hold at least one radiator and at least one component connected to at least one vibration exciter, whereby the component can be retained acoustically and/or vibrationally decoupled on a retaining device for the component and can be covered by it at least to a large extent. 
         [0032]    Such a support structure can be installed in the motor vehicle in the production process as a prefabricated, highly integrated supplied component and thus can contribute to saving installation time and costs. 
         [0033]    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 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 
         [0034]    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: 
           [0035]      FIG. 1  illustrates a front part of a motor vehicle from a side according to an embodiment of the invention; 
           [0036]      FIG. 2  is an enlarged view according to view II of  FIG. 1 ; 
           [0037]      FIG. 3  is a top plan view of the retaining device for the plate-like component, retaining the vibration exciter, according to view III of  FIG. 2 ; 
           [0038]      FIG. 4  is an enlarged view according to view IV of  FIG. 2 , but in a further embodiment; 
           [0039]      FIG. 5  illustrates the front part of a motor vehicle from a side in an embodiment of the invention; 
           [0040]      FIG. 6  illustrates a view, comparable to  FIG. 2 , of an embodiment of the invention; 
           [0041]      FIG. 7   a  illustrates the flat component, illustrated without a vibration exciter, in an embodiment; 
           [0042]      FIG. 7   b  illustrates the flat component of  FIG. 7   a  in a side view; 
           [0043]      FIG. 8  a illustrates the flat component, illustrated without a vibration exciter, in an embodiment; 
           [0044]      FIG. 8   b  illustrates the flat component of  FIG. 8   a  in a side view; 
           [0045]      FIG. 9  illustrates the fastening of the component with the vibration exciter to a bottom wall of an engine shield; 
           [0046]      FIG. 10  illustrates the fastening of the component with the vibration exciter to an upper wall of an engine shield; 
           [0047]      FIG. 11  shows a detailed illustration of the bottom wall according to  FIG. 9 ; and 
           [0048]      FIG. 12  shows a detailed illustration for  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0049]    A motor vehicle K, made as an all-electric vehicle, can be seen in  FIG. 1 . Of course, the solution of the invention can also be used advantageously for other motor vehicles that can be driven “without noise,” as mentioned, for example, in the introduction to the description, for example electric vehicles. 
         [0050]    Vehicle K has an engine compartment  2  that can be covered by a hood  10  with an electric motor  3 , used for traction of motor vehicle K. 
         [0051]    A support structure  1  (mounting support) at whose bottom area a radiator  4  and a fan  5  are mounted or taken up can be seen in the front area of vehicle K (so-called front end). 
         [0052]    Radiator  4  is used for cooling power electronics and power units such as, for example, those of electric motor  3 . 
         [0053]    Air intakes  6  are provided in front of radiator  4 , so that incoming air can reach radiator  4  more easily while vehicle K is being driven. 
         [0054]    A plate-like component  7  is fastened above radiator  4  to mounting support  1  by means of a frame-like retaining part  11 . A vibration exciter  8  is attached in turn to component  7  approximately in the middle of the surface extension of plate-like component  7 . 
         [0055]    Vibration exciter  8  can operate, for example, piezoelectrically, electrostatically, magnetically, electromagnetically, or in some other suitable manner. It is used for the vibrational excitation of plate-like component  7 , whereby the frequencies of vibration exciter  3  can be controlled. Necessary electrical connections are not shown in greater detail. 
         [0056]    In order to optimally decouple plate-like component  7  vibrationally and/or acoustically from the body of motor vehicle K, component  7  is connected at fastening points  73  in a vibrationally decoupled manner to frame-like retaining part  11 , and frame-like retaining part  11  is connected in turn via vibrationally decoupled fastening elements  9  to mounting support  1 . Fastening elements  9  are preferably made as multicomponent parts (for example, steel/elastomer). 
         [0057]    Very good sound radiation S in the direction of travel and thereby an extremely good warning effect for passersby are possible by positioning component  7  together with vibration exciter  8  in mounting support  1 . 
         [0058]      FIGS. 2 and 3  show that frame-like retaining part  11  has a circular, plate-like depression T, in which component  7  (cf. also  FIG. 8 ) is inserted and is connected in a vibrationally decoupled manner at fastening points  73  (openings) to retaining part  11 . 
         [0059]    Depression T is surrounded by a flange-like frame  113 , which likewise has fastening points  117  (openings), in order to mount retaining part  11  at said fastening points  117  by means of vibrationally decoupled fastening elements  9  (not shown in greater detail) on support structure  1 . 
         [0060]    Depression T is formed by a circumferential, lateral wall  112 , which merges into a back wall  110 . “Back” in this case therefore means facing engine  3  (cf. also  FIG. 1 ). As is evident, wall  110  of retaining part  11  covers a large part of a back side  72 , facing it, of plate-like component  7 , so that back wall  72  of component  7  is no longer visible to a great extent. Only a preferably circular opening  115  remains in the center of wall  110 . Opening  115  surrounds vibration exciter  8  in the immediate vicinity, preferably concentrically. With good shielding, an unimpeded mobility of vibration exciter  8  can be assured by opening  115 , which is preferably only slightly larger in its diameter than the surface extension of vibration exciter  8  in the same direction. An overall flat and compact construction of retaining part  11  is also possible thereby. 
         [0061]    Further, there can be a front grille  13  for better protection of a front side  71  of component  7 , said side otherwise not covered by retaining part  11 . 
         [0062]    It is shown in  FIG. 4  that opening  115  can be provided with a cover  12 . Cover  12  is flexible and air-permeable and can be formed of foam, for example. 
         [0063]    In addition or alternatively, back wall  110  can have a sound-absorbing surface  14 . Said surface can be connected integrally to wall  110  or also be formed as a sound-absorbing coating (e.g., nonwoven material). 
         [0064]    Retaining part  11  in the exemplary embodiments is formed as a single piece. In a departure therefrom, it is naturally conceivable to configure retaining part  11  in the form of multiple parts as well. 
         [0065]    It can be gathered from  FIG. 5  that retaining part  11  for the sound-generating system ( 7 ,  8 ) can also be attached in the same way to hood  10 . 
         [0066]      FIG. 6  describes a different embodiment of the invention in which, in contrast to  FIG. 2 , back wall  110  is completely closed. Component  7  is retained vibrationally decoupled on flanges  114 , located in depression T, at fastening points  73 . If necessary, flanges  114  enable the creation of a greater distance to back wall  110 . Further, a ventilation opening  116  is provided for pressure equalization. 
         [0067]    This embodiment offers the best acoustic properties, but is not quite as compact as the solution according to  FIG. 2 . 
         [0068]    In a departure from the exemplary embodiments, vibration exciter  8  can also be similarly mounted on front side  71  of plate-like component  7 . A plurality of vibration exciters  8  can also be attached to the front and/or back side  71 ,  72  of plate-like component  7 . 
         [0069]    As is evident from  FIG. 7 , plate-like component  7  can be, for example, rectangular, especially approximately square, in outline. On the periphery, it has four tongue-like elements  70 , which are connected integrally to component  7  and are provided with fastening points  73  at their ends in the form of openings. Clear spaces are labeled with the number  75 . 
         [0070]    Instead of on the periphery, tongue-like elements however can also be located farther inward on the surface of component  7 , as indicated by way of example with the dashed lines by the reference numbers  70 ′ and  75 ′. A fastening opening  74  for vibration exciter  8  (not shown here) can be seen in the center of component  7 . 
         [0071]    As a departure from this,  FIG. 8  shows plate-like component  7  having an approximately circular shape in outline, which can be used preferentially especially in tight places. 
         [0072]      FIG. 9  shows as a further embodiment a motor vehicle K, particularly a hybrid vehicle, with an engine block  15  (only an internal combustion engine is shown), which is shielded laterally by side walls  220  by a capsule-like engine shield  20 , downwardly toward a roadbed (not shown) by a bottom wall  221 , and upwardly by an upper wall  222 . 
         [0073]    Other necessary units and apertures for exhaust gas lines, supply lines, and the like are not shown. 
         [0074]    As a departure from the illustrated exemplary embodiment, it is conceivable that engine shield  20  also comprises fewer or more of the illustrated walls  220  to  222 . 
         [0075]    In the present case, a plate-like component  7  is fastened by means of vibrationally decoupled fastening elements  9  to bottom wall  221 , namely, on the inner side facing engine block  15 . Component  7  in turn supports a vibration exciter  8  on its side facing engine  15 . Vibration exciter  8  can operate, for example, piezoelectrically, electrostatically, magnetically, electromagnetically, or in some other suitable manner. 
         [0076]    As a further embodiment a motor vehicle K with an engine shield  20  can be seen in  FIG. 10 ; in contrast to  FIG. 9 , planar component  7 , supporting vibration exciter  8 , is fastened outside to upper wall  222  of engine shield  20 . Here as well, vibration exciter  8  is again attached on the side, facing engine  15 , of plate-like component  7 . 
         [0077]      FIG. 11  now shows a somewhat detailed illustration of bottom wall  221  according to  FIG. 9 . 
         [0078]    Wall  221  has an outer, frame-like, peripheral fastening region, in which, on the one hand, retaining flange  2210  is located, which can be pushed onto the body, and, on the other, mounting grommets  2211  are located for screw connection to the body. Polypropylene (PP  20 ), for example, is highly suitable as a material for wall  221 . 
         [0079]    Reinforcement ribs  2212  are provided to achieve a desired degree of stiffness. 
         [0080]    Plate-like component  7  supporting vibration exciter  8  is fastened, for example, screwed, to wall  221  in the front area of wall  221  via vibrationally decoupled fastening elements  9 . Component  7  can also be provided with reinforcement ribs  76 . 
         [0081]    Necessary electrical lines for electrical control and the on-board voltage supply for vibration exciter  8  are not shown in greater detail. 
         [0082]    As is evident from  FIG. 12 , the vibrationally decoupled fastening elements  9  are connected integrally as tongue-like elements  751  to component  7 . They have a widened, round end area  752  with a cup-like depression  753 . 
         [0083]    On the bottom of cup-like depression  753 , there is a fastening opening  750  at which end area  752  of tongue-like element  751  and thereby component  7  can be fastened, for example, screwed, to bottom wall  221  of engine shield  20 . For this purpose, wall  221  also has a suitable fastening opening  2213 . 
         [0084]    Tongue-like elements  751  are formed by surrounding fastening openings  750  in each case by a slit-like recess A. 
         [0085]    The invention is not limited to the above exemplary embodiment(s). These were used only for a general explanation of the core idea of the invention. On the contrary, the invention within its scope of protection can also assume embodiments and shapes different from those in the previously described exemplary embodiments or shapes. In this case, it can have in particular features that represent a combination of the individual features in the particular claims. 
         [0086]    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.