Patent Publication Number: US-2007120087-A1

Title: Valve body with multiconical geometry at the valve seat

Description:
FIELD OF THE INVENTION  
      In fuel injection systems that can be used for instance in mixture-compressing or self-igniting internal combustion engines, magnet valves are now used for controlling the fuel quantity. In the closed state of the magnet valves, these valves assure that no fuel can flow out of an enclosed volume. In the open state, conversely, the fuel flow is enabled. With such valves, when used for instance in fuel injection systems for direct-injection engines, high system pressures, which are on the order of magnitude of more than 1500 bar, must be mastered. The valve seats embodied in these valves are manufactured with a single cone in an I-valve (inward-opening arrangement) or O-valve (outward-opening arrangement) version.  
     PRIOR ART  
      Valves that are used in fuel injection systems for self-igniting internal combustion engines are becoming smaller and smaller for the sake of installation space, yet conversely the system pressures to be mastered have a sharply rising trend. In such valves, this leads to higher loads, especially in the valve seat region. Because of these higher loads, not only cavitation but also mechanical wear of the valve seat in the sealing region can occur. One such valve is known from German Patent DE 42 38 727 C2.  
      Wear that occurs at elevated loads in the valve seat region leads to a change in the switching behavior with regard to the opening and closing process over the life of such valves and thus leads to a drift in the injection quantity as the life of a valve with a single cone ages.  
      In the conventional valve seat of a magnet valve, of the kind used in high-pressure injection systems, for instance, the valve needle and the valve body in which the valve needle is guided are made with different cone angles. Because of this, there is a seat angle difference in the valve seat region. On the one hand, the seat angle difference makes for a precisely defined sealing edge when the valve is new. In valve seats with single cones, the seat angle difference also causes a damping gap to develop between the valve needle and the valve body.  
      Because of the mechanical wear in the sealing region that occurs over the life of the magnet valve, the cone angles of the valve needle and the valve body become similar with increasing time in operation. From a linear seal (sealing edge) when the magnet valve is new, over the course of time in operation a flattened seal is created once the valve has been run in. Depending on the configuration of the surface structure of the sealing face that is established because of wear, high pressure P HP  can get under this sealing face. Because of the transition from linear sealing in the new state to a flattened seal in the run-in state, the hydraulically effective sealing diameter d hydr. . shifts from the original sealing edge into the wear region. This means that the original hydraulically effective sealing diameter d hydr. . decreases. The hydraulically effective sealing diameter d hydr.operation,DL  established in the run-in state with a flattened seal is less than the hydraulically effective sealing diameter d hydr. . in the new state, and as a result the hydraulically effective surface area changes. Because of a change in the hydraulically effective surface area in the valve seat region of the magnet valve, the force ratios engaging the valve needle change, which causes an unwanted change in the switching behavior of the magnet valve over its life and thus causes a quantity drift.  
     SUMMARY OF THE INVENTION  
      If the least possible quantity drift in the fuel quantity to be injected into the combustion chamber of an internal combustion engine over the service life is to be attained, the hydraulically effective sealing diameter d hydr. . must remain as constant as possible over the life of a valve. To achieve this, the valve seat, proposed according to the invention, of a magnet valve for use in high-pressure fuel injection systems has for example a double-cone or multiconical geometry, including undercuts. The design of a valve seat proposed according to the invention is distinguished by the fact that in the sealing region of the valve seat, the seat angle difference is reduced, and downstream of the sealing region (the free region) of the valve seat, the seat angle difference is increased. The double-cone or multiconical geometry, when the valve is new, leads to a flattened seal, that is, a flattened contact region, since the slight seat angle difference and roughness or tolerances in smoothness of the valve needle and the valve body assure that not only will the outer edge of the valve needle rest on the valve body, but so will “roughness points”, which originate in the machining, between the valve needle and the valve body. When the valve is new, accordingly, unlike the variant embodiments with a single cone known from the prior art, there is no linear sealing region (or sealing edge). Because of an increased seat angle difference in the free region, that is, downstream of the sealing region, a limitation of the ensuing mechanical wear can be achieved. By this provision, the hydraulically effective sealing diameter d hydr. . in the new state is reduced, and in the run-in state of the valve it is stabilized. Thus the hydraulically effective sealing diameter d hydr. . can be kept virtually constant over the life of the valve proposed according to the invention. As a result, a quantity drift in the fuel quantity injected into the combustion chamber of an internal combustion engine, and its variation over the life of the valve, can be reduced. Because of the essentially constant hydraulically effective sealing diameter d hydr. ., a change in the switching behavior of the valve, equipped with the seat geometry proposed according to the invention, can accordingly advantageously be maximally avoided.  
      The embodiment proposed according to the invention of a valve seat as a double-cone or multiconical geometry can advantageously be employed especially in high-pressure injection systems, of the kind used in self-igniting internal combustion engines, in which pressures of more than 1500 bar must remain capable of being mastered. The design proposed according to the invention of the valve seat can be employed in both inward-opening valves (I-valves) and outward-opening valves (O-valves). In an advantageous variant embodiment, because of conical faces extending on both sides of a sealing edge, if the sealing edge becomes worn the hydraulically effective sealing diameter d hydr. . is unchanged, since the seat adaptation that occurs in operation because of the flattening of the sealing edge simultaneously extends both radially inward and radially outward. As a result, from an originally linear sealing, over the course of the life of the valve, with increasing flattening of the sealing edge, a sealing face that becomes larger symmetrically on both sides is created, whose characteristic is a constant, hydraulically effective sealing diameter d hydr. . 
    
    
     DRAWING  
      The invention is described in further detail below in conjunction with the drawing.  
      Shown are:  
       FIG. 1 , a variant embodiment of a double-cone seat geometry in an I-valve;  
       FIG. 2 , a further variant embodiment of a double-cone seat geometry in an I-valve in the valve seat region;  
       FIG. 3 , a further variant embodiment of a valve seat region in an I-valve, with conical faces extending on both sides of the sealing edge;  
       FIG. 4 , a further variant embodiment of a sealing edge in a valve seat region of an I-valve, again with conical faces on both sides of the sealing edge;  
       FIG. 5 , a variant embodiment of a multiconical geometry in the valve seat region, with a pocket let into the valve body;  
       FIG. 6 , a first variant embodiment of a multiconical geometry in the valve seat region of an O-valve;  
       FIG. 7 , a further variant embodiment of a valve seat region in an O-valve;  
       FIG. 8 , a further variant embodiment of a valve seat region in an O-valve with a chamfered valve body sealing face;  
       FIG. 9 , a further variant embodiment of a valve seat region designed according to the invention, with a sealing edge toward which two frustoconical faces extend; and  
       FIG. 10 , a further variant embodiment of a valve seat region in an O-valve, with a pocket integrated into the valve body sealing face. 
    
    
     VARIANT EMBODIMENTS  
       FIG. 1  shows a variant embodiment of the multiconical geometry, proposed according to the invention, at a valve seat region of an I-valve.  
      A magnet valve  1 , such as a diesel magnet valve used in high-pressure fuel injection systems, includes a valve body  2  and a valve member  3  guided in it and embodied as a valve needle  3 . The valve member  3  and the valve body  2  are constructed symmetrically to a line of symmetry. A valve seat region between the valve body  2  and the valve needle  3  is identified by reference numeral  5 . By means of the valve seat region  5 , in the closed state of the valve needle  3 , a high-pressure region  6 , in which a high pressure PHP prevails, and a low-pressure region  7 , in which a lesser pressure P LP  prevails, are separated from one another.  
      In the variant embodiment of the valve seat region  5  shown in  FIG. 1 , a sealing edge  8  is defined by the sealing edge diameter  25  (d S ) of a first conical face  20  of a multiple cone  19 . Inside the first conical face  20 , a seat angle difference  18  is embodied. The seat angle difference  18  amounts to only a few degrees (≦5°). When the valve  1  is new, the sealing edge diameter  25  d S  approximately coincides with the hydraulically effective sealing diameter  14  d hydr,new . Because of the seat angle difference  18  embodied at the first conical face  20 , the contact between the sealing edge  8  and the seat face  29 , over the course of operation, changes over into a flattish contact, but because of the slight seat angle difference  18 , it is assured that a hydraulically effective sealing diameter  15  d hydr. operation  (dashed line in  FIG. 1 ), which is established over the course of the time in operation, essentially matches the hydraulically effective sealing diameter  14  d hydr.,new  of the valve when new. The second conical face  21 , adjoining the first conical face  20 , of the multiconical geometry  19  can be provided with a conical face whose angle is within an annular region  28  (see the illustration in  FIG. 1 ). Because of the provision of the second conical face  21 , which does not come into contact with the seat face  29  of the valve body  2 , it is assured that the sealing action occurs only between the first conical face  20 , embodied with the seat angle difference  18 , and the seat face  29  of the valve body  2 . As a result, the inlet width and closure width are limited.  
      The angle of inclination, with which a second conical face  21  of the multiconical geometry  19  is embodied, can be within the range represented by the angle of inclination  28 . The second conical face  21  of the multiconical geometry  19 , below the second encompassing edge  12  on the valve needle  3 , adjoins the first conical face  20  of the multiconical geometry  19 . In cooperation with the seat face  29  of the valve body  2 , in the closed state of the valve needle  3 , both when the valve is new and in the state in which the valve needle  3  is fully run in, a flattish sealing of the high-pressure region  6 , where high pressure P HP  off from the low-pressure region  7 , in which low pressure P LP  prevails, is achieved. In the view shown in  FIG. 1 , the outside diameter of the valve needle  3  is represented by reference numeral  24  (d N ).  
      The spacing shown in  FIG. 1  between the first conical face  20  of the valve needle  3  and the seat face  29  of the valve body  2  functions, given a suitable selection of the cone angle  28  of the second conical face  21 , as a damping angle, since upon closure of the valve needle  3 , the fuel located in the gap must be expelled, so that the impact of the first conical face  20  on the seat face  29  is damped by the fuel still contained in a damping gap  10 .  
       FIG. 2  shows a further variant embodiment of a valve seat region, proposed according to the invention, in an I-valve.  
      The high-pressure region  6 , which is supplied via the high-pressure inlet  23 , is separated from the low-pressure region  7 , in which low pressure P LP  prevails, by the first conical face  20  of the valve needle  3 .  
      In a distinction from the variant embodiment shown in  FIG. 1 , in the variant embodiment shown in  FIG. 2  of an I-valve  22  proposed according to the invention, the second conical face  21  is folded over inward; that is, in comparison to the variant embodiment shown in  FIG. 1 , the second conical face  21  makes no contribution to the damping.  
       FIG. 3  shows a multiconical geometry at the valve needle of an I-valve.  
      It can be seen from the illustration in  FIG. 3  that the sealing edge  8 , when the valve  1  is new, is embodied with the sealing edge diameter  25  (d S ). The sealing edge diameter  25  (d S ), when the valve  1  is new, corresponds to the hydraulically effective sealing diameter d hydr.new  (see reference numeral  14 ). The conical faces  20  and  21  of the multiconical geometry  19  extend on both sides of the sealing edge  8  in the valve seat region  5 . The first conical face  21  of the multiconical geometry  19  is embodied with the seat angle difference  18 , while the second conical face  21 , which adjoins the first conical face  20  below the second encompassing edge  12 , has a further seat angle difference  27 , relative to the seat face  29  and the second conical face  21 . Given a flattening that ensues in the course of operation in the region of the sealing edge  8  upon contact with the seat face  29 , diametrically opposite, of the valve body  2 , a seat adaptation occurs simultaneously both radially inward and radially outward, so that as the running in increases and with the ensuing wear, the hydraulically effective sealing diameter d hydr.operation  remains essentially unchanged. In the view shown in  FIG. 3 , the sealing edge  8  coincides with the second encompassing edge  12  of the valve needle  3 .  
       FIG. 4  shows a variant embodiment of the valve seat proposed according to the invention of  FIG. 3 .  
      Unlike the variant embodiment shown in  FIG. 3 , in the variant embodiment of  FIG. 4 , a further, third conical face  41  is embodied below the second conical face  21 . The further, third conical face  41  defines the possible inlet or wear region of the first conical face  20 , so that the wear can propagate only at most to the second encompassing edge  12 . The mode of operation of the valve seat shown in  FIG. 4  is analogous to the mode of operation of the valve seat shown in  FIG. 3 .  
       FIG. 5  shows a further variant embodiment of a valve seat region designed according to the invention.  
      Unlike the variant embodiments shown in  FIGS. 1 through 4 , in the variant embodiment shown in  FIG. 5 , a pocket  36  (or relief groove) is embodied in the seat face  29  of the valve body  2 . The pocket  36  is located facing the second encompassing edge  12  that separates the first conical face  20  from the second conical face  21  of the multiconical geometry  19 . The task of the pocket  36  embodied in the seat face  29  is to limit the wear, which occurs upon contact of the first conical face  20  with the seat face  29 , to the conical face  20 .  
      The first conical face  20  is embodied with the seat angle difference  18 , while the second conical face  21 , below the second encompassing edge  12 , on the valve needle  3  has a cone angle  27 , which is greater than the seat angle difference  18  of the first conical face  20 . In this case again, the sealing edge diameter  25  (d S ) coincides with the outer diameter of the first conical face  20  of the multiconical geometry  19 . The needle diameter  24  (d N ) of the valve needle  3  simultaneously corresponds to the reference diameter of the valve body  2 . With the variant embodiment shown in  FIG. 5  of an I-valve  22  as well, a virtually constant hydraulically effective sealing diameter when the valve is new can be achieved, compared to the state in which the valve seat has been run in.  
      While in the variant embodiments of the invention in  FIGS. 1 through 5 , I-valve seats  22  have been described, that is, valves that open inward, in the variant embodiments sketched below, O-valves will be described. In the I-valves identified by reference numeral  22 , the valve needle  3  opens in the direction of the high-pressure inlet  23  and enables a fluidic communication between the high-pressure region  6  and the low-pressure region  7 . By comparison, the variant embodiments described below in conjunction with  FIGS. 6 through 10  involve O-valves, in which the valve needle  3  opens away, or in other words outward, relative to the high-pressure inlet  23  into the high-pressure region  6 .  
       FIG. 6  shows a first variant embodiment of a valve seat region for an O-valve, with an outward-opening valve body.  
      The magnet valve  1  shown in  FIG. 6  includes the valve body  2 , on which the seat face  29  is embodied. Via a high-pressure inlet  23  that penetrates the valve body  2  of the magnet valve  1 , fuel at high pressure flows to the high-pressure region  6 , in which high pressure P HP  prevails. The valve needle  3  of the magnet valve  1  is constructed symmetrically to the line of symmetry  4 . A first encompassing edge of the outward-opening valve needle  3  is identified by reference numeral  32 , while a further, second encompassing edge of the outward-opening valve needle  3  is identified by reference numeral  33 . In the valve seat region  5 , diametrically opposite the seat face  29  of the valve body  2 , the multiconical geometry  19  is embodied, which includes both a first conical face  20  and a second conical face  21 . The first conical face  20  of the multiconical geometry  19  is embodied with the seat angle difference  18 , while the second conical face  21 , which adjoins the first conical face  20  along the first encompassing edge  32  of the valve needle  3 , is embodied with a cone angle  27  that is greater than the seat angle difference  18 . In the open state, shown in  FIG. 6 , of the outward-opening valve needle  3 , the high-pressure region  6  and the low-pressure region  7 , in which low pressure P LP  prevails, communicate with one another. The sealing edge diameter  25  d S  is largely equivalent to the hydraulically effective sealing diameter d hydr.,new    14  in the new state of the valve  1 . While the first conical face  20  of the multiconical geometry  19  is embodied with a seat angle difference  18 , the second conical face  21  extends with a further seat angle difference  27 , which is selected to be greater than the seat angle difference  18  of the first conical face  20 . As a result, the wearing region at the valve needle  3  is limited to the region between the sealing edge  8  and the first encompassing edge  32  of the outward-opening valve needle  3 . This region (see reference numeral  9 ) identifies the inlet/closure region between the seat face  29  on the valve body  2  and the first conical face  20  of the multiconical geometry  19 .  
      In the O-valve  37  shown in  FIG. 6 , the sealing edge  8  is embodied at the edge of the seat face  29 , diametrically opposite the first conical face  20 .  
       FIG. 7  shows a further variant embodiment of an O-valve, having a valve needle on which a multiconical geometry is embodied.  
      Unlike the variant embodiment shown in  FIG. 6  of the design proposed according to the invention of the valve seat region  5 , a recess configured in pocketlike fashion is located on the valve body  2 . Inside the recess of the valve body  2 , into which the high-pressure inlet  23  discharges, the sealing edge  8  is embodied at the seat face  29 . In the variant embodiment shown in  FIG. 7  as well of the valve seat region  5 , proposed according to the invention, on the magnet valve  1 , the sealing edge  8  is located facing the first conical face  20 . The first conical face  20  of the multiconical geometry  19  extends with the seat angle difference  18  relative to the seat face  29  of the valve body  2 . The first encompassing edge  32  of the outward-opening valve needle  3  of the magnet valve  1  is adjoined by the second conical face  21  of the multiconical geometry  19 , which in comparison to the first conical face  20  is embodied with the cone angle ( 27 ). The first conical face  20  forms a sealing face  17 , while conversely the second conical face  21  of the multiconical geometry  19 , because of the larger cone angle  27 , represents a free face for limiting wear.  
      Because of the embodiment of a pocket in the high-pressure region  6  between the valve body  2  and the valve needle  3 , the diameter d N    24  of the valve needle  3  and the seat diameter d S    25  do not coincide in the variant embodiment of  FIG. 7 ; instead, the seat diameter d S    25  exceeds the needle diameter d N    24  of the valve needle  3 . By comparison to the variant embodiment of the O-valve  37  shown in  FIG. 6 , in the variant embodiment in  FIG. 7  the sealing edge  8  is shifted outward by the amount of the pocket depth in the valve body  2 , so that in comparison to the variant embodiment of  FIG. 6 , a greater seat diameter d S    25  ensues.  
      In the new state of the valve  1 , the hydraulically effective sealing diameter d hydr.,new  of the valve coincides approximately with the sealing edge diameter  25  (d S ). Over the course of operation of the valve, the hydraulically effective sealing diameter  25  d hydr.operation  conversely shifts only insignificantly, as indicated by dashed lines in  FIG. 7 .  
      In the variant embodiment shown in  FIG. 7  of an O-valve  37 , the sealing edge  8  is located facing approximately the middle of the first conical face  20  of the multiconical geometry  19 , which has the seat angle difference  18 . The first conical face  20  of the multiconical geometry  19  functions as a sealing face, while the second conical face  21  with the seat angle difference  27 , relative to the seat face  29  of the valve body  2 , serves as a free face.  
       FIG. 8  shows a variant embodiment of the valve seat region, proposed according to the invention, with an oblique face embodied on the seat face of the valve body.  
      Unlike the variant embodiments of  FIGS. 6 and 7 , referring to an O-valve  27  and in which the seat face  29  extends continuously, in the variant embodiment shown in  FIG. 8 a  chamfer  38  on the seat face  29  is provided, which is inclined by an angle to the seat face  29 . The transition from the seat face  29  to the chamfer  38  forms the sealing edge on the valve body  2 . Analogously to the multiconical geometries on the valve needle  3  shown in  FIGS. 6 and 7 , the valve needle  3  shown in  FIG. 8  is embodied with the first conical face  20  and the second conical face  21 , which have cone angles  18  and  27 , respectively, that differ from one another; that is, the seat angle difference  18  and the angle difference  27  of the first conical face  21 . The sealing edge diameter  25  (d S ) is identical to the hydraulically effective sealing diameter d hydr.,new  in the new state. Over the course of operation, the inlet/closure region propagates both radially inward and radially outward, so that the hydraulically effective sealing diameter d hydr.operation  remains constant.  
      The first conical face  20  and the second conical face  21  are separated from one another by the first encompassing edge  32  of the outward-opening valve needle  3 . The second encompassing edge  33  of the outward-opening valve needle  3  forms the boundary of the second conical face  21  on the valve needle  3 . The transition point where the seat face  29  of the valve body  2  merges with the chamfer  38  forms the sealing edge  8 .  
      In the position shown in  FIG. 8  of the valve needle  3  in the valve body  2 , the high-pressure inlet  23 , which discharges into the high-pressure region  6 , and the low-pressure region  7 , in which low pressure P LP  prevails, communicate with one another, so that via the high-pressure inlet  23 , fuel flows via the high-pressure region  6  into the low-pressure region  7  of the magnet valve  1 .  
       FIG. 9  shows a further variant embodiment of an outward-opening valve needle.  
      The sealing edge  8  of the valve needle  3  is located in the first conical face  20  of the multiconical geometry  19  and is embodied with the seat angle differences  18  and  18   a.  Extending radially inward and radially outward, respectively, on either side of the sealing edge  8  relative to the valve needle  3 , the first conical face  20  has seat angle differences  18  and  18   a . If in operation of the outward-opening valve needle  3  of the O-valve  37  the sealing edge  8  strikes the seat face  29  of the valve body  2 , then because of the seat angle differences  18  and  18   a  on both sides, the flattening of the sealing edge  8  extends symmetrically along the first conical face  20 , or in other words symmetrically radially outward as well as symmetrically radially inward. As a result, in operation of the magnet valve  1 , a uniformly extending flattening at the sealing edge  8  is achieved. The limitation of the inlet/closure region  9 , in the variant embodiment shown in  FIG. 9  of the valve seat region  5  proposed according to the invention, is effected as a result of the fact that the second conical face  21  of the multiconical geometry  19  has a more-acute cone angle than the first conical face  20 .  
      In the new state of the valve  1 , in the variant embodiment of  FIG. 9 , the diameter  25  of the sealing edge  8  at the valve needle  3  and the hydraulically effective sealing diameter d hydr.,new    14  coincide. Over the course of operation, a hydraulically effective sealing diameter d hydr.operation    15  ensues, which differs only insignificantly from the hydraulically effective sealing diameter  14  in the new state of the valve  1 .  
      The boundary of the second conical face  21 , acting as a free face, of the multiconical geometry  19  of the valve needle  3  is formed by the second encompassing edge  32  of the outward-opening valve needle  3 . In the position of the valve needle  3  of  FIG. 9 , the high-pressure inlet  23  of the valve body  2 , the high-pressure region  6  in which high pressure PHP prevails, and the low-pressure region  7  in which low pressure P LP  prevails, communicate fluidically with one another.  
       FIG. 10  finally shows a variant embodiment of an O-valve with a pocket embodied in the seat face of the valve body.  
      In the variant embodiment of the valve seat region  5  according to the invention shown in  FIG. 10 , the seat face  29  of the valve body  2  has a recess  36  configured in pocketlike fashion.  
      The pocket  36 , which is embodied in the seat face  29  of the valve body  2 , has the function of limiting the inlet/closure region  9  to the region between the sealing edge  8  at the valve body  2  and the first conical face  20  of the multiconical geometry  19 . The same function at the valve needle  3  is performed by the second conical face  21  of the multiconical geometry  19 , since the cone angle of the second conical face  21  has a more-acute course than that of the first conical face  20 .  
      The valve needle  3  of the outward-opening valve  37  has the multiconical geometry  19 , which includes both the first conical face  20  and the second conical face  21 .  
      The second conical face  21  of the multiconical geometry  19  of the outward-opening valve needle  3  is embodied with the further seat angle difference  27 . The first conical face  20  is defined by the first encompassing edge  32 , at which the first conical face  20  merges with the second conical face  21 , the latter being defined by the second encompassing edge  33 . In the variant embodiment shown in  FIG. 10  of an outward-opening valve  37 , the inlet/closure region  9  is limited to the part of the seat face  29  located between the sealing edge  8  and the pocketlike recess  36 , and to the first conical face  20 .  
      In the new state of the outward-opening valve  37  shown in  FIG. 10 , the hydraulically effective sealing diameter d hydr.,new  (see reference numeral  14 ) coincides with the diameter of the sealing edge  8  in the valve body  2 . The hydraulically effective sealing diameter d hydr.operation  (see reference numeral  15 ) that ensues after sometime in operation differs only insignificantly from the hydraulically effective sealing diameter  14  d hydr.,new  of the outward-opening valve  37 , so that even after relatively long operation of the outward-opening valve  37 , no impermissible forces that adversely affect the closing and opening behavior of the outward-opening valve  37  can be caused by the change in hydraulic surface areas. As a result, the replicability both of injection quantities and of the instants of opening and closing is assured.  
     List of Reference Numerals  
     
         
           1  Magnet valve  
           2  Valve body  
           3  Valve needle  
           4  Line of symmetry  
           5  Valve seat region  
           6  High-pressure region (PHP)  
           7  Low-pressure region (PLP)  
           8  Sealing edge  
           9  Inlet/closure region  
           10  Damping gap  
           11  First encompassing edge  
           12  Second encompassing edge  
           13  Conical face of valve needle  
           14  Hydraulically effective sealing diameter d hydr,new    
           15  Hydraulically effective sealing diameter d hydr,operation    
           18  Seat angle difference (from sealing edge inward)  18   a  Seat angle difference (from sealing edge outward)  
           19  Multiconical geometry  
           20  First conical face  
           21  Second conical face  
           22  I-valve seat  
           23  High-pressure inlet  
           24  Diameter of valve needle (d N )  
           25  Sealing edge diameter (d S )  
           27  Further seat angle difference between seat face  29  and second conical face  21   
           28  Angular region  
           29  Seat face of valve body  2   
           32  First encompassing edge of valve needle  
           33  Second encompassing edge of valve needle  
           36  Relief groove  
           37  O-valve seat  
           38  Chamfer  
           40  Third encompassing edge, valve needle  
           41  Third conical face  
           42  Further conical face