Patent Publication Number: US-2016230729-A1

Title: Device for Fastening at Least One Fuel Injection Nozzle

Description:
The invention relates to a device for fastening at least one fuel injection nozzle for an internal combustion engine according to the preamble of patent claim  1 . 
     From the publication JPH03182680 A, a device is known by which a fuel injection nozzle of an internal combustion engine is disposed in a bore of a cylinder head. The device has a holding device designed in the manner of a two-armed lever which engages, on the one hand, with a first arm at a collar-like stop of the fuel injection nozzle and, on the other hand, with a second arm at a screw head of a cylinder head screw. A mounting screw extends between the two arms, which is screwed into a thread in the cylinder head and clamps the fuel injection nozzle against a stop in the bore of the cylinder head by inter-positioning a seal. Moreover, a nozzle tip of the fuel injection nozzle penetrates a through-hole in the cylinder head and, by doing so, is connected to a combustion chamber of the internal combustion engine. 
     An assembly for attaching an injection nozzle in a holder can be seen from the publication DE 195 54 065 A1, which has a receiving aperture for the injection nozzle. A clamping element is mounted at the injection nozzle. The clamping element is connected to the holder by means of mounting screws and, that is, in such a manner that the injection nozzle positively fits against a stop in the receiving aperture. A sealing disk is installed between injection nozzle and stop. Additionally, a nozzle tip of the injection nozzle penetrates a through-hole bore in the holder so that fuel is infeedable into a downstream combustion chamber. 
     The publication DE 26 49 357 describes a connection of a fuel injection nozzle with a cylinder head of an internal combustion engine. The fuel injection nozzle rests with a guide shaft in a bore of the cylinder head. Outside of the bore, a pressure piece acts upon the fuel injection nozzle in such a manner that, by means of a mounting screw, said fuel injection nozzle is clamped in the axial direction against a stop in the bore. Longitudinal center axes of the mounting screws and of the fuel injection nozzle run at a defined distance to one another. 
     It is the object of the present invention to design a device for fastening at least one fuel injection nozzle by a holding device, which is characterized by good functioning, easy installation and simple implementability. 
     According to the present invention, this object is achieved by the features of patent claim  1 . Further features embodying the present invention are included in the dependent claims. 
     The primary advantages achieved by the present invention are to be seen in that the device having the holding device holds the fuel injection nozzle at the housing section of the internal combustion engine perfectly in place. In this instance, the fuel injection nozzle may be easily connected to the holding device as well as the holding device may be easily connected to the housing section; the disassembly is similarly simple. Within this context, the holding device implementable by the skilled person is also to be mentioned. The structural design of the holding device having a mounting flange, jacket pot and mounting flange sets standards in the field of fastening fuel injection nozzles. It is to be highlighted that at least the jacket pot is formed by a rotationally symmetrical body to which the mounting flange and the holding socket serving for axial and radial locking are connectable without difficulty, and commercial feather keys serving to secure the fuel injection nozzle into the holding socket. A superior fastening of the holding device is possible if the mounting screws are disposed in an evenly distributed manner over a circumferential center line of its mounting flange. An outstanding connection of the holding device via the mounting flange and the mounting screws is achieved in that said holding device is attached at the housing section constituting a valve cover of the internal combustion engine. An excellent interaction of the holding device with the fuel injection nozzle results if the jacket pot, which, for example, is made out of sprung steel, has defined elastic properties in the axial direction. This is supported in that the jacket pot is implemented in the manner of a converging conical shell, starting from the mounting flange in the direction of the holding socket. Furthermore, it is positive that the shell of the jacket pot adjacent to the mounting flange is provided with a first conical shell section extending only over a partial length of the shell, a second shell section extending from one end of the partial length of the shell to the holding socket. It is advantageous in this embodiment that the first shell section encloses, with reference to a longitudinal center axis of the jacket pot, a smaller angle than a corresponding angle of the second shell section. 
     A high-ranking further embodiment of the holding device is achieved in that the device is well suited to receive two fuel injection nozzles and that it has a first and a second jacket pot having a first and a second holding socket. For instance, the first and the second jacket pots are combined into an assembly substantially integrally manufactured which rests with a surrounding support flange on a corresponding receiving plane at the housing section constituting a valve cover. This embodiment is complemented in a particular manner in that a cross sectionally U-shaped groove for receiving a sealing body, which is operative between groove and assembly, is provided next to the receiving plane of the valve cover. Finally, this holding device is optimized in a targeted fashion in that a single mounting screw, which is operatively connected to a thread of the cylinder head and which holds the assembly in place at the valve cover in a functionally adequate way, is situated in a longitudinal center plane between the first and the second jacket pot. 
    
    
     
       The drawings show exemplary embodiments of the present invention, which are subsequently described in more detail. 
         FIG. 1  shows a schematic slanted partial view onto an internal combustion engine; 
         FIG. 2  shows a section along line II-II of  FIG. 1  on a larger scale, having a first embodiment of a holding device for a fuel injection nozzle—version I; 
         FIG. 3  shows a detail X of  FIG. 2  on a larger scale; 
         FIG. 4  shows a schematic slanted view of an interior side of a valve cover, having a screw connection of the holding device according to  FIGS. 2 and 3 ; 
         FIG. 5  shows a schematic slanted view from above onto the holding device having a fuel injector; 
         FIG. 6  shows a section along line IV-IV of  FIG. 1 , having a holding device for a plurality of fuel injection nozzles—version II; and 
         FIG. 7  shows an isometric explosion drawing of the holding device according to  FIG. 6 . 
     
    
    
     There exists a cylinder head  2  of an internal combustion engine  1 , which accommodates camshafts  3  and  4  actuating two not-shown valves and which is screwed together with a valve cover  5 . A covering hood  6  of an intake chamber  7 , which is at least partially formed by valve cover  5 , extends approximately parallel to valve cover  5 — FIG. 1 . Internal combustion engine  1  is designed as an outboard engine for actuating a ship propeller and is integrated into a boat. In addition, this internal combustion engine has two parallel crankshafts which are aligned perpendicular to a waterline of the boat. Both crankshafts are actuated by two pistons which are moved back and forth in horizontal bores by cylinders of a cylinder crank housing. In doing so, each piston acts upon said crankshaft using two connecting rods. Moreover, internal combustion engine  1  operates according to the diesel method and, that is, with direct injection; common-rail system. From the publication DE 10 2012 015 907 B3, the latter, specific features of internal combustion engine  1  having two parallel crankshafts follow from the description and illustrations in a plausible manner. 
     The direct injection system comprises fuel injection nozzles  8  and  9  for the cylinders, for the fastening of which a device  10  is provided at valve cover  5  of internal combustion engine  1 — FIG. 2 . Each fuel injection nozzle, for example, fuel injection nozzle  8 , is at least in sections inserted into a bore  11  of cylinder head  2 , fuel injection nozzle  8  feeding fuel, using a nozzle tip  12 , into a combustion chamber  13  between cylinder head  2  and a piston  14 . With holding device  15 , fuel injection nozzle  8  forms, for example, pre-installed assembly  16 , and holding device  15  is, by means of a screw connection  17 , fixedly connected to a housing section  18  of internal combustion engine  1 . In this instance, holding device  15  clamps—version I—the fuel injection nozzle against a stop  20  in bore  11  of cylinder head  2  by inter-positioning a sealing plate  19 . 
     Holding device  15  comprises a jacket pot  21  surrounding fuel injection nozzle  8  in areas, which on a side facing away from nozzle tip  12  has a mounting flange  22 . At a distance to mounting flange  22 , a holding socket  23  delimiting a partial area  22  of fuel injection nozzle  8  by a bore  24  is provided at jacket pot  21 . Feather keys  25  illustrated only schematically are operative between holding socket  23  and fuel injection nozzle  8 , as a result of which fuel injection nozzle  8  is secured in the axial and radial direction. Within holding socket  23 , a sealing body  25 ′ is provided on a side facing mounting flange  22 , which is operative between a bore section of bore  24  and a shaft area of fuel injection nozzle  8  and which prevents fuel from spilling. 
     Jacket pot  21  is a rotationally symmetrical body which is integrally manufactured from mounting flange  22  and holding socket  23 — FIG. 3 ; however, it is also conceivable to produce said parts separately from one another and to assemble them afterwards. Screw connection  17  comprises mounting screws  26 ,  27  and  28 , which are evenly disposed over circumferential center line  29  of annular mounting flange  22 , and holds holding device  15  at housing section  18  constituting valve cover  5 — FIG. 2 . 
     Jacket pot  21  projecting into valve cover  5  has defined elastic properties in axial direction A-A. Spring steel is a suitable material for jacket pot  21 ; however, composites can also be used for the manufacture of said jacket pot. Jacket pot  21  is designed, starting from mounting flange  22  in the direction of holding socket  23 , in the fashion of a tapered conical shell  30 , said conical shell, starting at mounting flange  22  in the direction of holding socket  23 , being provided with a first shell section  31  extending only over a partial length TI of shell  30 . A second shell section  33  extends from an end  32  of partial length TI of first shell section  31  in the direction of holding socket  23 . First shell section  31  encloses, with reference to a longitudinal center plane B-B, a smaller angle a than a corresponding angle β of second shell section  33 . 
     A holding device  34  is configured to receive two fuel injection nozzles  35  and  36 —version II—and is composed of a first jacket pot  37  and a second jacket pot  38  which are connected to a first holding socket  39  and a second holding socket  40 . First and second jacket pots  37  and  38  are combined via a frame  41  into a substantially oval assembly  42  which is, for example, made out of metal, plastic or the like and which is integrally manufactured, for example, by deforming. Assembly  42  or frame  41  is provided with a surrounding support flange  43  which rests upon a corresponding receiving plane  44  of a housing section  45  in the shape of a valve cover  46 . 
     Adjacent to receiving plane  44  of valve cover  46 , a U-shaped groove  47  is provided in a cross section which is inclined sideways by 90°. Groove  47  serves to accommodate a sealing body  48  which is operative between groove  47  and frame  41  of assembly  38 . Finally, a mounting screw  49 , which is operatively connected to a thread  50  in a cylinder head  51  and which keeps assembly  32  in position under tension at valve cover  42 , is provided in a longitudinal center plane C-C between first jacket pot  37  and second jacket pot  38 .