Abstract:
Damping elements for a fuel injection valve insertable into a receiving conduit of a cylinder head of an internal combustion engine are disposed between a valve housing of the fuel injection valve and a wall of the receiving conduit of the cylinder head. These damping elements, inter alia, decrease acoustic transfer from the fuel injection valve to the cylinder head. It is disadvantageous that conventional damping elements require a great deal of axial installation space with respect to a valve axis and have comparatively high manufacturing costs. With the damping element according to example embodiments of the present invention, the installation space required is reduced. Provision is made, according to example embodiments of the present invention, for the damping element to be in plate-shaped fashion.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a damping element for a fuel injection valve. 
     BACKGROUND INFORMATION 
     A damping element for a fuel injection valve insertable into a receiving conduit of a cylinder head of an internal combustion engine, which element is disposed between a valve housing of the fuel injection valve and a wall of the receiving conduit of the cylinder head, is described in German Published Patent Application No. 100 38 763. The damping element is made up of two rigid rings between which an elastic intermediate ring is disposed. The damping element, inter alia, decreases acoustic transfer from the fuel injection valve to the cylinder head. It is disadvantageous that the damping element requires a great deal of axial installation space with respect to a valve axis, and has comparatively high manufacturing costs. 
     SUMMARY 
     The damping element according to example embodiments of the present invention, in contrast, may provide that an improvement may be achieved in simple fashion in that with a damping effect that is as good as in the existing art, less axial installation space with respect to the valve axis is necessary, in that the damping element is arranged in plate-shaped fashion. Sufficient elasticity of the damping element is achieved because of the plate-shaped arrangement and the mounting of the fuel injection valve on a collar of the plate-shaped damping element. 
     The damping element may have a first portion for bracing against a shoulder of the receiving conduit in the cylinder head and a second portion, angled with respect to the first portion, for bracing of the fuel injection valve, since axial installation space is saved by the angling of the second portion and sufficient elasticity of the damping element is moreover achieved. 
     The first portion may extend from the second portion radially inward with respect to a valve axis, since in this fashion the shoulder of the receiving conduit against which the damping element abuts is easier to manufacture than in the case of a first portion that extends radially outward from the first portion. 
     The first portion may be arranged in substantially flat or convex fashion. 
     The second portion may be arranged in collar-shaped, substantially conical, and/or convex fashion. The necessary elasticity of the damping element is thereby achieved. 
     The damping element may have a passthrough opening that can be penetrated by the fuel injection valve. The passthrough opening may be arranged on the first portion. 
     The first portion and the second portion may have at least one support, for bracing against the cylinder head or for bracing of the fuel injection valve, that is arranged in planar fashion or as an elevation. The smaller the support surface of the damping element on the cylinder head, the better the solid-borne sound-damping effect. 
     Provision may be made for the damping element to have two cover panels and an elastic intermediate layer disposed between the cover panels. This damping element fabricated from composite material exhibits particularly good solid-borne sound damping, since mechanical vibration energy is converted into thermal energy by internal friction in the elastic intermediate layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional of a fuel injection valve in a receiving bore of a cylinder head 
         FIG. 2  illustrates aspects of an example embodiment of the present invention. 
         FIG. 3  illustrates aspects of an example embodiment of the present invention. 
         FIG. 4  illustrates aspects of an example embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Several exemplary embodiments of the present invention are depicted in simplified fashion in the drawings and explained further in the description that follows.  FIG. 1  shows, in section, a fuel injection valve in a receiving bore of a cylinder head,  FIG. 2  illustrates aspects of an exemplary embodiment,  FIG. 3  illustrates aspects of an exemplary embodiment, and  FIG. 4  illustrates aspects of an exemplary embodiment, in respective details II-IV according to  FIG. 1 . 
       FIG. 1  is a simplified depiction of a fuel injection valve in a receiving bore of a cylinder head, having a damping element according to example embodiments of the present invention between the fuel injection valve and the cylinder head. 
     A fuel injection valve  1  is disposed in a receiving conduit  2  of a cylinder head  3  of an internal combustion engine. Fuel injection valve  1  serves to inject fuel into a combustion chamber  4  of the internal combustion engine and is used, for example, in so-called direct injection. Fuel injection valve  1  has at its inflow end  5 , for example, a plug connection to a fuel distribution line  8  that is sealed, for example, by a seal  9  between fuel distribution line  8  and an inflow fitting  10  of fuel injection valve  1 . Fuel injection valve  1  also has an electrical connector  11  for electrical contacting of an actuator of fuel injection valve  1 , for example, an electromagnetic or a piezoelectric or magnetostrictive actuator, for actuation of fuel injection valve  1 . 
     Fuel injection valve  1  has a valve housing  14  that encompasses an actuator portion  14 . 1  and a nozzle portion  14 . 2 . The cylindrical nozzle portion  14 . 2  has a smaller diameter than the cylindrical actuator portion  14 . 1  of valve housing  14 , so that an annular valve shoulder  15  is formed at the transition between portions  14 . 1 ,  14 . 2 . Valve shoulder  15  is, for example, conically beveled radially outward toward actuator portion  14 . 1  with respect to a valve axis  16 , so that a conical region  17  is formed on valve housing  14 . The actuator, which actuates a valve needle, is disposed in actuator portion  14 . 1 . The valve needle extends from the actuator into nozzle portion  14 . 2  of valve housing  14 . The valve needle has, in conventional fashion, a closure element that coacts with a valve seat disposed on the nozzle portion. In order to open the fuel injection valve, the valve needle having the closure element lifts off from the valve seat so that an outlet gap is formed between the closure element and the valve seat, and fuel that travels via fuel distribution line  8  and inflow fitting  10  into valve housing  14  is injected through the outlet gap into combustion chamber  4 . 
     Receiving conduit  2  is divided into a first conduit portion  2 . 1  for the reception of actuator portion  14 . 1  of valve housing  14  and a second conduit portion  2 . 2  for the reception of nozzle portion  14 . 2  of valve housing  14 . The diameter of second conduit portion  2 . 2  is smaller than the diameter of first conduit portion  2 . 1 . At the transition from the smaller-diameter second conduit portion  2 . 2  into the larger-diameter first conduit portion  2 . 1 , an annular first shoulder  2 . 1  is formed at which, for example, fuel injection valve  1  is mounted. For easier introduction of nozzle portion  14 . 2  of fuel injection valve  1  into second conduit portion  2 . 2  of receiving conduit  2 , second conduit portion  2 . 2  is conically expanded at the end facing toward actuator conduit  2 . 1  A sealing ring  22  provided on nozzle portion  14 . 2  of fuel injection valve  1  seals a gap between second conduit portion  2 . 2  and nozzle portion  14 . 2  of fuel injection valve  1 . 
     Provided between fuel injection valve  1  and receiving conduit  2  is a damping element  25  that abuts, for example, against first shoulder  21  of receiving conduit  2  and braces fuel injection valve  1  in conical region  17 . 
     Damping element  25  serves to reduce the transfer of vibration and solid-borne sound from the fuel injection valve to cylinder head  2  of the internal combustion engine. A fuel injection valve, e.g., one having a piezoelectric actuator, can be excited to vibrate strongly, e.g., in a context of multiple injections per injection cycle, so that effective solid-borne sound decoupling between the fuel injection valve and the cylinder head is necessary in order to prevent troublesome noise, proceeding from the fuel injection valve, from being perceived in a vehicle. 
     According to example embodiments of the present invention, damping element  25  is arranged in plate-shaped fashion. An arrangement that saves a great deal of installation space is thereby achieved. For example, only 1.5 millimeters are available for damping element  25  in the axial direction between first shoulder  21  of cylinder head  3  and fuel injection valve  1 . 
     Damping element  25  has, according to example embodiments of the present invention, a first portion  26  for bracing or abutment against a shoulder of receiving conduit  2  in cylinder head  3 , for example, first shoulder  21 , and a second portion  27 , angled with respect to first portion  26 , for bracing the fuel injection valve. The plate shape of damping element  25  is created by second portion  27  that is angled with respect to first portion  26 . First portion  26  is arranged, for example, in circular fashion, and second portion  27  in annular fashion. The two portions  26 ,  27  are joined integrally to one another. Damping element  25  has a passthrough opening  28  that imparts an annular shape to damping element  25  and through which fuel injection valve  1  can penetrate. Passthrough opening  28  is provided in first portion  26 , so that base  26  of plate  25  has an opening. 
     Damping element  25  is manufactured, e.g., from metal, for example, steel, and/or plastic. Damping element  25  is fabricated, for example, from sheet metal, for example, having a thickness of 1.5 millimeters. The plate shape of damping element  25  is achieved, for example, by a reshaping method, metal-removing shaping, or a primary forming method. 
     First portion  26  extends, for example, from second portion  27  radially inward with respect to valve axis  16 . First portion  26  can, however, also be disposed on second portion  27  radially outward with respect to valve axis  16 . The radially inwardly disposed first portion  26  has the advantage, as compared with the radially outwardly disposed first portion  26 , that the shoulder of cylinder head  3  against which the damping element abuts is easier to manufacture. 
     First portion  26  is, for example, arranged in substantially flat or convex fashion, and abuts with a first support  29 , for example, against the planar first shoulder  21 . The surface area of first support  29  is to be made as small as possible in order to decrease acoustic transmission. First support  29  is, for example, the flat underside, facing toward first shoulder  21 , of damping element  25 . First support  29  can, however, also be constituted by one or more elevations, disposed on the lower side of damping element  25 , that can have any shape and are, for example, rounded in order to achieve good radial displaceability. 
     Second portion  27  protrudes in collar-shaped fashion from first portion  26  of damping element  25 . For example, second portion  27  is arranged at least substantially conically; a convexity outward toward cylinder head  3  can also be provided. Second portion  27  abuts with a second support  30 , for example, against conical region  17  of valve housing  14 . Damping element  25  is centered with respect to valve axis  16  by conical region  17  of fuel injection valve  1  and by conical second region  27  that coacts with conical region  17 . Second support  30  is part of the upper side, facing toward fuel injection valve  1 , of damping element  25 . One or more elevations are provided, for example, on the upper side of damping element  25 , which elevations form second support  30  and are, e.g., rounded. An annular flange  33  is disposed, for example, as second support  30  on the upper side of damping element  25 . What results is, for example, a linear contact of fuel injection valve  1  against damping element  25 , thus achieving gimbaled mounting. 
     Forces proceeding from fuel injection valve  1  are transferred via second support  30 , collar  27  of damping element  25 , and first support  29  to cylinder head  3 . There exists between first support  29  and second support  30  not only an axial spacing but also a radial spacing, which represents a lever arm. This lever arm of collar  27  results in an axial elasticity of damping element  25  with respect to valve axis  16 , which elasticity brings about a solid-borne sound damping in that the periodic switching pulses of the actuator of fuel injection valve  1  are transferred in greatly attenuated fashion via first shoulder  21  to cylinder head  3 . Very small relative motions occur between fuel injection valve  1  and damping element  25  at second support  30 , so that additional vibration damping is accomplished by friction. The larger the lever arm is dimensioned, the greater the elasticity of damping element  25 . 
     The transition from first portion  26  to second portion  27  can be sharp-edged or rounded. 
     Because of the planar arrangement of first shoulder  21 , damping element  25  disposed in receiving conduit  2  is displaceable radially with respect to valve axis  16 . The radial displaceability of damping element  25  is necessary because, as a result of tolerances, a conduit axis  31  of nozzle portion  2 . 2  of receiving conduit  2  and an inflow axis  32  of fuel distribution line  8  do not always align. 
       FIG. 2  shows a damping element according to an example embodiment of the present invention, in a detail II according to  FIG. 1 . 
     In the context of the damping element according to  FIG. 2 , parts that remain the same, or function in the same manner, as compared with the fuel injection valve according to  FIG. 1  are labeled with the same reference characters. 
     The raised flange  33  on an end of second portion  27  facing away from first portion  26  is disposed on the upper side facing toward fuel injection valve  1 . 
       FIG. 3  shows a damping element according to an example embodiment of the present invention, in a detail III according to  FIG. 1 . 
     In the context of the damping element according to  FIG. 3 , parts that remain the same, or function in the same manner, as compared with the fuel injection valve according to  FIG. 1  and the exemplary embodiment according to  FIG. 2  are labeled with the same reference characters. 
     The damping element according to  FIG. 3  differs from the damping element according to  FIG. 2  in that the longitudinal extension of collar  27  is greater. The rigidity of damping element  25  is thereby increased. Flange  33  is disposed not at an end, facing away from first portion  26 , of second portion  27 , but instead at approximately half the longitudinal extension of collar  27  on the upper side facing toward fuel injection valve  1 . 
       FIG. 4  shows a damping element according to an example embodiment of the present invention, in a detail IV according to  FIG. 1 . 
     In the context of the damping element according to  FIG. 4 , parts that remain the same, or function in the same manner, as compared with the fuel injection valve according to  FIG. 1  and the exemplary embodiments according to  FIGS. 2 and 3  are labeled with the same reference characters. 
     The damping element according to  FIG. 4  differs from the damping elements according to  FIG. 2  and  FIG. 3  in that the damping element is manufactured from a composite material made up of two cover panels  35  and an elastic intermediate layer  36  provided between cover panels  35 . Cover panels  35  and intermediate layer  36  are in each case joined fixedly to one another. In a context of flexural vibrations of damping element  25 , cover panels  35  shift relative to one another with the result that periodic shear deformations occur in elastic intermediate layer  36 . The internal friction in elastic intermediate layer  36  causes vibratory energy to be lost as mechanical energy, so that vibration damping, and therefore solid-borne sound damping, is achieved. 
     First portion  26  of damping element  25  is not planar but instead convex toward first shoulder  21 . Second portion  27  is arranged in substantially conical and additionally convex fashion. Adjoining second portion  27  radially outward is, for example, a second shoulder  34 . The transition from second portion  27  to second shoulder  34  is, for example, rounded. 
     The composite material, which is at first planar in its initial shape, is converted into a plate shape, for example, by reshaping. 
     It is also possible to dispose multiple damping elements  25  according to the exemplary embodiments presented, one above another in layered fashion, in order to achieve even better noise damping.