JP2005163650A - In-cylinder fuel injection device for internal combustion engine - Google Patents

Abstract

An in-cylinder fuel injection device for an internal combustion engine is provided that allows a fuel distribution pipe and a fuel introduction pipe to communicate with each other easily and reliably while avoiding damage caused by twisting of a seal member.
A fuel injection valve I for opening a fuel injection hole 23 to inject fuel directly into a combustion chamber 15, a fuel introduction pipe 2 connected to a fuel inlet cylinder 45 of the fuel injection valve I, and the fuel introduction In the in-cylinder fuel injection device including the fuel distribution pipe D connected to the pipe 2, the joint member 100 is provided so as to project from the cap portion 100a communicating with the fuel distribution pipe D and the outer periphery of the open end of the cap portion 100a. The outer side of the fuel introduction pipe 2 is composed of an outward flange 100b that is overlapped via a seal member 106, while a male screw 107 is formed on the outer periphery of the end of the fuel introduction pipe 2 adjacent to the outward flange 100b. An inward flange 101 c that presses the outward flange 10 b against the fuel introduction pipe 2 is formed in the connection nut 101 that is screwed into the male screw 107.
[Selection] Figure 4

Description

  The present invention is connected to an electromagnetic fuel injection valve that opens a fuel injection hole to inject fuel directly into a combustion chamber of an engine body, and to a fuel inlet cylinder that extends on the opposite side of the fuel injection valve to the fuel injection hole. The present invention relates to an improvement of an in-cylinder fuel injection device for an internal combustion engine, which includes a fuel introduction pipe and a fuel distribution pipe connected to the fuel introduction pipe via a joint member.

Such an in-cylinder fuel injection device for an internal combustion engine is already known as disclosed in, for example, Patent Document 1 below.
JP-A-9-317606

  By the way, in a conventional in-cylinder fuel injection device for an internal combustion engine, in order to connect the fuel distribution pipe to the fuel introduction pipe, a joint that communicates with the fuel distribution pipe on the outer end face of the fuel distribution pipe and the outer end face of the fuel distribution pipe. The members are stacked with the first seal member in between, the first seal member is interposed between the outer end surface of the joint member and the head of the bolt passing through the joint member, and the bolt is screwed and tightened to the fuel introduction pipe. Thus, the joint member is fastened to the fuel introduction pipe.

  However, in such a case, when the bolt is screwed, the second seal member in contact with the head of the bolt may be twisted and damaged. Moreover, since it is necessary to provide the said bolt with the communicating hole which connects a joint member and a fuel introduction pipe | tube, a special volt | bolt is needed and becomes a hindrance in aiming at cost reduction.

  The present invention has been made in view of such circumstances, and an internal combustion engine in which a fuel distribution pipe and a fuel introduction pipe can be easily and reliably communicated with each other while avoiding damage caused by twisting of a seal member. It is an object of the present invention to provide an in-cylinder fuel injection device.

  In order to achieve the above object, the present invention provides an electromagnetic fuel injection valve that opens a fuel injection hole to inject fuel directly into a combustion chamber of an engine body, and the fuel injection valve on the side opposite to the fuel injection hole. An in-cylinder fuel injection device for an internal combustion engine, comprising: a fuel inlet pipe connected to a fuel inlet pipe extending to the fuel inlet pipe; and a fuel distribution pipe connected to the fuel inlet pipe via a joint member. A cap portion that communicates with the fuel distribution pipe and has one end surface open, and an outward flange that protrudes from the outer periphery of the cap portion and overlaps the outer end of the fuel introduction pipe via a seal member; On the other hand, a male screw is formed on the outer periphery of the end of the fuel introduction pipe adjacent to the outward flange, and the outward flange accompanying the screwing is connected to the connecting nut that is screwed to the male screw. For the introduction pipe A first feature in that it has formed an inward flange pressure.

  The engine body corresponds to a cylinder head 1 in an embodiment of the present invention described later.

  Further, in addition to the first feature, the present invention has a second feature in that a flat portion for engaging the rotation preventing tool is formed on the outer peripheral surface of the cap portion.

  According to the first feature of the present invention, the seal member is only interposed between the fuel introduction pipe and the joint member, and there is no seal member in contact with the connection nut. Therefore, it can always exhibit a good sealing function. In addition, the fuel introduction pipe and the joint member can be easily connected to each other with a connecting nut without using a special bolt having a fuel passage.

  Further, according to the second feature of the present invention, when the connecting nut is screwed and tightened, the rotation of the joint member is reliably prevented by engaging the anti-rotation tool with the flat part on the outer periphery of the cap part. Therefore, not only the twist of the sealing member but also the distortion of the fuel distribution pipe connected to the joint member can be suppressed, which can contribute to ensuring high quality.

  Embodiments of the present invention will be described based on preferred embodiments of the present invention shown in the accompanying drawings.

  1 is a side view of an in-cylinder fuel injection device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along arrow 2 in FIG. 1, FIG. 3 is a sectional view taken along line 3-3 in FIG. 4 is a sectional view taken along line 4-4, FIG. 5 is an enlarged view of part 5 of FIG. 4, FIG. 6 is an enlarged view of part 6 of FIG. FIG. 9 is a sectional view taken along the arrow 9 of the fuel injection valve in FIG. 6, FIG. 10 is a sectional view taken along the line 10-10 in FIG. 9, FIG. 11 is a perspective view of the gasket in FIG. 6 is a perspective view of the backup ring in FIG. 6, FIG. 13 is a longitudinal sectional view of the seal ring in FIG. 7, and FIG. 14 is a perspective view of the conductor protecting member in FIG.

  1 and 2, an in-cylinder fuel injection device according to the present invention includes a fuel distribution pipe D attached to the outer surface of a cylinder head 1 of an electric ignition type multi-cylinder internal combustion engine E, and a plurality of branches of the fuel distribution pipe D. A plurality of injection valve protection cylinders 3, 3... Suspended from the pipes 6, 6... Via fuel introduction pipes 2, 2..., And electromagnetic fuel accommodated and held in these injection valve protection cylinders 3, 3.. The injection valve protection cylinders 3, 3,... Are attached to the cylinder head 1 of the internal combustion engine E corresponding to the respective cylinders.

  The fuel distribution pipe D includes a cylindrical distribution pipe body 5 and the same number of branch pipes 6, 6... Extending from the distribution pipe body 5 as the injection valve protection cylinder 3. The inner volume is sufficiently larger than each branch pipe 6. The distribution pipe body 5 is provided with a plurality of brackets 7, 7... Which are fixed to a plurality of attachment portions 8 formed on the outer surface of the cylinder head 1 with bolts 9, 9.

  The branch pipe 6 and the fuel introduction pipe 2 are connected to each other through a joint member 100 provided in the fuel introduction pipe 2 and communicate with each other. The connection structure will be described in detail later.

  A fuel supply pipe 10 connected to a discharge port of a fuel pump (not shown) is connected to one end of the distribution pipe body 5. A relief valve 11 is attached to one side of the distribution pipe body 5, and a fuel return pipe 12 for returning excess fuel to a fuel tank (not shown) is connected to one end of the relief valve 11.

  3 and 4, the cylinder head 1 of the internal combustion engine E is provided with a guide portion 17 extending from the center of the ceiling of the combustion chamber 15 corresponding to each cylinder to above the valve operating chamber 16. The guide portion 17 has a guide cap 18 screwed into the cylinder head 1 with its tip facing the combustion chamber 15, and a guide hole 19 formed in the cylinder head 1 so that the guide cap 18 can be inserted. And a guide cylinder 20 that has an inner peripheral surface that is continuous with the inner peripheral surface of the guide hole 19 and that is press-fitted into the cylinder head 1 and extends above the valve operating chamber 16. The guide cap 18 has a plate-like flange 18a at the upper end thereof, and the screwing depth of the guide cap 18 to the cylinder head 1 is regulated by contacting the cylinder head 1 on the lower surface of the outer periphery of the plate-like flange. Is done. Further, the guide cap 18 has a radially inward flange 18 b at the lower end opening to the combustion chamber 15. The injection valve protection cylinder 3 is fitted into the guide portion 17 thus configured.

  Next, the configuration of the electromagnetic fuel injection valve I housed and held in the injection valve protection cylinder 3 will be described with reference to FIGS.

  The valve housing 21 of the electromagnetic fuel injection valve I includes a cylindrical valve seat member 22 and a connecting cylinder that is press-fitted to the outer periphery of a flange 22a formed at the upper end of the valve seat member 22 and is laser welded W1. An annular lower yoke 24 having a portion 24a, a nonmagnetic collar 25 that is laser-welded over the entire circumference to the upper end of the lower yoke 24, and a liquid-tight over the entire circumference at the upper end of the nonmagnetic collar 25 A stopper core 27 is sandwiched between the valve seat member 22 and the lower yoke 24.

  The valve seat member 22 includes a fuel injection hole 23 opened at a lower end surface thereof, a conical valve seat 28 connected to the inner end of the fuel injection hole 23, and a cylindrical valve connected to a large diameter portion of the valve seat 28. A guide hole 29 is provided, and a swirl collar 30 is press-fitted into the lower portion of the valve guide hole 29. An axial through groove 31 and a swirl groove 32 inclined in a fixed direction with respect to the radial line are respectively provided on the outer peripheral surface and the lower end surface of the swirl collar 30. The swirl groove 32 imparts a swirl in a certain direction to the passing fuel.

  A needle valve 33 that cooperates with the valve seat 28 is accommodated in the valve seat member 22. The needle valve 33 extends vertically through the stopper plate 27 and the swirl collar 30 and is seated on the valve seat 28. The needle valve 33 is formed on the outer periphery of the needle 34 so as to cover the inner peripheral surface of the guide hole 19. A pair of slidable journals 35 and 35 and a stopper flange 36 facing the lower surface of the stopper plate 27, and the stopper flange 36 comes into contact with the lower surface of the stopper plate 27, thereby The valve opening stroke of the needle valve 33 is restricted. Each journal 35, 35 has a plurality of flat portions on the outer periphery that allow fuel to flow in the guide hole 19.

  A movable core 37 facing the lower end surface of the fixed core 26 inside the lower yoke 24 and the nonmagnetic collar 25 is integrally connected to the upper end portion of the needle 34. The movable core 37 can move up and down in the lower yoke 24 and the nonmagnetic collar 25 without contacting the inner peripheral surfaces thereof.

  The connecting structure of the needle 34 and the movable core 37 will be described in detail. The movable core 37 is provided with a bag-like connecting hole 38 opened at the lower end surface thereof, and a connecting shaft of the upper end portion of the needle 34 is provided in the connecting hole 38. The part 34a is press-fitted. A chamfer 39 is formed on the outer periphery of the upper end of the connecting shaft portion 34a to guide the press fitting of the connecting shaft portion 34a into the connecting hole 38. Further, a chip reservoir 40 is formed between the inner end face of the bag-like connecting hole 38 and the tip end face of the connecting shaft portion 34a to receive the chips generated during the press-fitting.

  Further, the depth of the bag-like connecting hole 38 is adjusted by adjusting the distance L1 from the upper surface of the stopper flange 36 to the upper end surface of the movable core 37 by adjusting the press-fitting depth of the connecting shaft portion 34a into the connecting hole 38. It is set to a sufficient size. The distance L1 is from the distance L2 from the lower end surface of the fixed core 26 combined with the needle valve 33 and the movable core 37 to the lower surface of the stopper plate 27, and between the opposing surfaces of the cores 26 and 37 when the needle valve 33 is opened. Is adjusted to a value obtained by subtracting the length ΔL corresponding to the minute gap to be provided at L1, that is, L1 = L2−ΔL. Therefore, when the needle valve 33 with the stopper flange 36 in contact with the lower surface of the stopper plate 27 is opened, a predetermined minute gap ΔL can be secured between the opposing surfaces of the cores 26 and 37.

  On the lower surface of the movable core 37, a thin cylindrical portion 37a is formed integrally with the connecting hole 38 so that the inner peripheral surface thereof continues. The lower end portion of the thin cylindrical portion 37a extends around the connecting shaft portion 34a. It is beaten and laser welded. At that time, the laser irradiation point is offset from the boundary between the connecting shaft portion 34a and the thin cylindrical portion 37a to the thin cylindrical portion 37a having a relatively low hardness, and both the heat input to the thin cylindrical portion 37a are increased while increasing the heat input to the thin cylindrical portion 37a. , 37a are laser welded to avoid cracks due to overheating of the relatively hard needle valve 33. Further, the heat input to the thin cylindrical portion 37a remains in the thin cylindrical portion 37a and does not reach the movable core 37 main body side. In this way, the needle valve 33 and the movable core 37 are firmly coupled to each other while avoiding the deterioration of the magnetic characteristics of the movable core 37.

  The fixed core 26 has a vertical hole 41 penetrating through the center, and a pipe-like retainer 42 fitted in the vertical hole 41 is fixed to the fixed core 26 by caulking from the outer periphery thereof. A coiled valve spring 43 that biases the movable core 37 in the valve closing direction of the needle valve 33 is contracted between the movable core 37 and the movable core 37. At that time, the set load of the valve spring 43 is adjusted by adjusting the fitting depth of the retainer 42 into the vertical hole 41. A positioning recess 44 that receives the lower end of the valve spring 43 is provided on the upper end surface of the movable core 37.

  The fixed core 26 is integrally provided with a fuel inlet cylinder 45 extending upward from the retainer 42, and a fuel filter 46 is attached to the inlet of the fuel inlet cylinder 45. The inside of the fuel inlet cylinder 45 communicates with the inside of the valve seat member 22 through the hollow portion of the retainer 42, the vertical hole 41, the plurality of cutout grooves 47 on the outer peripheral surface of the movable core 37, and the through hole 48 of the stopper plate 27. Is done.

  As shown in FIG. 8, the through hole 48 of the stopper plate 27 has a small diameter hole 48a located in the center of the stopper plate 27, which is smaller than the outer diameter of the stopper flange 36, and a dharma-like shape on one side of the small diameter hole 48a. Are connected to the stopper flange 36 and the large diameter hole 48b larger than the outer diameter of the journals 35, 35, and before the stopper plate 27 is assembled into the valve housing 21, the journals 35, 35 and the stopper flange of the needle valve 33 are provided. After inserting 36 into the large-diameter hole 48b, the stopper flange 36 is made to face the lower surface of the stopper plate 27 by shifting the needle 34 toward the small-diameter hole 48a.

  A coil assembly 50 that cooperates with the fixed core 26 and the movable core 37 is disposed on the outer periphery of the valve housing 21. The coil assembly 50 includes a bobbin 51 fitted to the outer periphery of the nonmagnetic collar 25 and the fixed core 26 and a coil 52 wound around the bobbin 51, and a magnetic body surrounding the coil assembly 28. The coil housing 53 is laser welded to the lower yoke 24, and an annular upper yoke 54 that is fitted to the outer periphery of the fixed core 26 and laser welded is superimposed on the upper end of the coil housing 53.

  A terminal holding part 51 a for holding a pair of terminals 55, 55 connected to both ends of the coil 52 is integrally formed at the upper end of the bobbin 51, and this terminal holding part 51 a is connected to the coil housing 53 and the upper yoke 54. Arranged in one continuous cutout 57,58.

  A cylindrical cover 59 made of synthetic resin is formed on the outer periphery of the valve housing 21 from the lower yoke 24 to an intermediate portion of the fuel inlet cylinder 45 by injection molding. At this time, the synthetic resin is filled into the coil housing 53 through the notches 57 and 58 and the notch 57 ′ on the other side of the coil housing 53 to cover the coil assembly 50.

  In FIG. 6, a hole 59 b provided in the covering body 59 is an insertion hole for a caulking tool that is used when the retainer 42 is fixed by caulking the outer periphery of the fuel inlet cylinder 45.

  As shown in FIGS. 5, 9 and 10, the pair of terminals 55, 55 are exposed from an upward stepped portion 59 a formed in the middle of the covering body 59. Two conductive wires 61, 61 extending from 66 are connected via a pair of connectors 60. Specifically, each connector 60 is first caulked at one end thereof to the terminal of the corresponding conductor 61, and terminals 55 and 55 corresponding to the other end are electrodeposited. A connecting portion cover 62 that covers the connecting portions of the connector 60, the terminals 55 and 55, and the conducting wires 61 and 61 is fitted to one side of the covering 59, and an insulating resin 63 is potted in the connecting portion cover 62. The connecting portion is embedded by the resin 63 and the connecting portion cover 62 is adhered to the cover 59.

  An identification number or symbol 64 of the fuel injection valve I is displayed on the outer surface of the connection portion cover 62, and the identification number or symbol 64 is a lower portion provided on one side wall of the injection valve protection cylinder 3 correspondingly. It can be recognized from the peephole 65.

  A mounting cap 70 that couples the injection valve protection cylinder 3 is attached to the front end portion, that is, the lower end portion of the fuel injection valve I. The mounting cap 70 includes a small-diameter cylindrical portion 70 a that fits to the outer peripheral surface of the tip end portion of the valve seat member 22, and a large-diameter cylindrical portion that fits to the outer peripheral surface of the connecting cylindrical portion 24 a and contacts the lower end surface of the lower yoke 24. 70b. An annular groove 71 is formed on the outer periphery of the distal end portion of the valve seat member 22, and a heat-resistant seal member 72 that is in close contact with the inner peripheral surface of the small-diameter cylindrical portion 70a is attached thereto.

  A press-fit portion 73 having a slightly larger diameter than the lower portion is formed in the upper portion of the outer peripheral surface of the connecting tube portion 24a, and the press-fit portion 73 is press-fitted into the upper inner peripheral surface of the large-diameter tube portion 70b. At that time, an annular stress relief groove 74 is formed in the upper end surface of the large-diameter cylindrical portion 70b in the vicinity of the inner peripheral surface thereof, and the inner peripheral surface of the large-diameter cylindrical portion 70b due to the excessive load at the time of the press-fitting. The diameter expansion deformation is allowed by the stress relief groove 74. On the upper surface of the large-diameter portion 70 b, the outer peripheral surface is wider than the inner peripheral surface of the stress relief groove 74, and the wide surface abuts against the lower end surface of the lower yoke 24. The press-fit limit between 73 and the large-diameter cylindrical portion 70b is regulated.

  The lower yoke 24 includes a small flange 75 having a slightly larger diameter than the cover 59 covering the coil housing 53 on the outer periphery of the lower end portion, and the large diameter cylindrical portion 70b has a diameter larger than that of the small flange 75 on the outer periphery of the upper end portion. The large flange 76 is integrally provided, and the small flange 75 is joined to the upper surface of the large flange 76 over the entire circumference by laser welding W2. The welding heat at that time is absorbed by the small flange 75 and has a very small effect on the entire lower yoke 24, so that the magnetic properties of the lower yoke 24 can be prevented from deteriorating.

  The injection valve protection cylinder 3 is fitted to the outer peripheral surface of the small flange 75 while accommodating the cover 59, and the lower end surface is brought into contact with the upper surface of the large flange 76. And the outer periphery of the contact portion of the large flange 76 is joined by laser welding W3 over the entire circumference. In this way, the fuel injection valve I is held by the injection valve protection cylinder 3 via the mounting cap 70.

  As shown in FIGS. 5 and 11, a gasket 77 made of a thin spring steel plate is attached to the outer periphery of the small diameter cylindrical portion 70 a of the attachment cap 70. The gasket 77 includes an annular elastic seal portion 77a that elastically contacts the end surface of the small-diameter cylindrical portion 70a, and a plurality of leg pieces 77b that bend and extend in the axial direction from the outer periphery of the seal portion 77a. The gasket 77 is attached to the small diameter cylindrical portion 70a by elastically engaging the claw portion 77c formed at the tip of each leg piece 77b with the outer peripheral groove 78 of the small diameter cylindrical portion 70a.

  In FIG. 5 again, the injection valve protection cylinder 3 is inserted into the guide portion 17 with the mounting cap 70 at the top. The small diameter cylindrical portion 70 a of the mounting cap 70 is fitted in the guide cap 18 of the guide portion 17 together with the gasket 77, and the injection valve protection cylinder 3 is fitted in the guide cylinder 20 of the guide portion 17. At that time, the seal portion 77a of the gasket 77 is sandwiched between the end surface of the small diameter cylindrical portion 70a of the mounting cap 70 and the inward flange 18b of the guide cap 18 to achieve airtightness therebetween.

  A metal gasket 80 is also interposed between the lower surface of the large-diameter portion 70b of the mounting cap 70 and the bottom surface of the guide cap 18 in the dish-shaped flange 18a. A cylindrical heat insulating space 79 is defined between the 70 and the guide cap 18.

  As shown in FIG. 6, a seal member 83 and a backup ring 84 that supports the lower surface of the annular seal housing 82 on the outer periphery of the upper end of the fuel inlet cylinder 45 are mounted and are in close contact with the seal member 83. Thus, the lower end portion of the fuel introduction pipe 2 is fitted to the outer periphery of the upper end portion of the fuel inlet tube 45. As shown in FIG. 12, the backup ring 84 is provided with an abutment 84a inclined with respect to the axis thereof, and a tapered inner peripheral surface 84b having a large diameter downward, and the inner peripheral surface thereof. A tapered guide surface 82a facing 84b is provided in the lower portion of the seal housing 82.

  Thus, when the backup ring 84 is pressed downward together with the seal member 83 by the high-pressure fuel from the fuel introduction pipe 2, the diameter of the backup ring 84 is expanded by the interaction between the tapered guide surface 82a and the inner peripheral surface 84b. The seal member 83 is supported while being in close contact with the inner peripheral surface of the tube 2, and an appropriate sealing function of the seal member 83 is ensured.

  The injection valve protection cylinder 3 is provided with a pair of upper peeping holes 85 located on both sides of the seal housing 82, and when the fuel introduction pipe 2 is fitted into the fuel inlet cylinder 45, The proper mounting state of the seal member 83 and the backup ring 84 can be confirmed from these upper peep holes 85.

  As shown in FIG. 7, the fuel introduction pipe 2 extends to above the injection valve protection cylinder 3, a closing ring 87 is press-fitted into the outer peripheral surface of the intermediate part, and is inserted into the outer peripheral shoulder 2 a of the fuel introduction pipe 2. All-around laser welding W4 is fixed. The closing ring 87 presses the outer periphery of the lower end portion into the inner peripheral surface of the injection valve protection cylinder 3 to hold the fuel introduction pipe 2 and the injection valve protection cylinder 3 concentrically. At the same time, the closing ring 87 is integrated by applying a flange 87a projecting to the outer periphery of the closing ring 87 to the upper end surface of the injection valve protection cylinder 3 and laser welding W5. On the outer peripheral surface of the fuel introduction pipe 2 exposed above the closing ring 87, a pair of diametrically opposed flat portions 110, 110 are formed, and the fuel introduction tube 2 is formed using these flat portions 110, 110 as an assembly reference. And the fixing position of the closed ring 87 are determined.

  Further, a sealing ring 88 made of an elastic material such as rubber for sealing between the closing ring 87 and the guide cylinder 20 is fitted to the outer periphery of the closing ring 87 above the flange 87a. The seal ring 88 is fixed in the axial position on the closing ring 87 by fitting the annular positioning protrusion 89 on the inner periphery thereof into the annular positioning groove 90 on the outer periphery of the closing ring 87.

  As clearly shown in FIG. 13, an annular inner peripheral seal lip 88 a is integrally formed on the inner peripheral surface of the positioning ring 89 of the seal ring 88, and an annular outer peripheral seal lip 88 b is integrally formed on the outer peripheral surface of the seal ring 88. The inner peripheral seal lip 88a is in intimate contact with the bottom surface of the positioning groove 90, and the outer peripheral seal lip 88b is in intimate contact with the inner peripheral surface of the guide cylinder 20, so that the gap between the closing ring 87 and the guide cylinder 20 is sealed. Is done.

  As shown in FIGS. 3, 7, and 14, the two conducting wires 61, 61 are provided on one side of the upper end portion of the injection valve protection cylinder 3 and one side of the flange 87 a of the closing ring 87. Are passed through the notches 91 and 92, and are further drawn out through the through holes 93 and 93 provided on one side wall of the seal ring 88. A plurality of seal lips 88 c, 88 c, which are in close contact with the outer peripheral surface of the insulation coating of the conducting wires 61, 61 are integrally formed on the inner peripheral surfaces of the through holes 93, 93 of the seal ring 88. The upper ends of the through holes 93, 93 are integrally formed on the upper surface of the seal ring 88 and extend to the upper end surface of the extension portion 88 d protruding higher than the upper surface of the closing ring 87, and are pulled out from the through holes 93, 93. The lead wires 61 and 61 are prevented from coming into contact with the closing ring 87.

  A conductor protecting member 96 for preventing the conductors 61 and 61 from protruding from the notches 91 and 92 is attached to the notches 91 and 92. The conductive wire protection member 96 is made of synthetic resin, and is formed by connecting the base ends of a pair of holding pieces 96a and 96a having holding grooves 96b and 96b with open surfaces facing each other at the distal ends. When the gap between the pieces 96a and 96a is opened and the two conducting wires 61 and 61 are engaged with the holding grooves 96b and 96b, and then the holding pieces 96a and 96a are fitted into the notches 91 and 92, both holding The pieces 96a and 96a are held in proximity to each other so as to prevent the conductors 61 and 61 from being detached from the holding grooves 96b and 96b.

  The seal ring 88 is connected with a breather tube 97 that allows breathing inside the guide cylinder 20, and the open end of the breather tube 97 is disposed in a place where rainwater, washing water, etc. are difficult to be applied.

  Now, the connection structure of the branch pipe 6 and the fuel introduction pipe 2 will be described with reference to FIGS.

  The joint member 100 provided corresponding to each branch pipe 6 of the fuel distribution pipe D is composed of a cap portion 100a having only a lower end surface opened and an outward flange 100b projecting from the outer periphery of the open end of the cap portion 100a. Composed. A connecting nut 101 is rotatably fitted on the outer periphery of the joint member 100. In the inner periphery of the connecting nut 101, a flange housing portion 101a for housing the outward flange 100b, a female screw 101b adjacent to the lower side of the flange housing portion 101a, and an upper side of the flange housing portion 101a An inward flange 101c facing the upper surface of the outward flange 100b is formed, and the inner diameter of the female screw 101b is set to be slightly larger than the outer diameter of the outward flange 100b, and the inner diameter of the inward flange 101c is the cap portion 100a. Is set to be slightly larger than the outer diameter. On the outer peripheral surface of the cap portion 100a, a pair of plane portions 100c and 100c that are parallel to each other and that can engage a non-rotating tool such as a spanner are formed.

  Alternatively, a connection hole 104 communicating with the inside of the cap portion 100a is provided on one side of the upper end portion, and the downstream end portion of the branch pipe 6 corresponding thereto is fitted and brazed. Thus, since the inward flange 101c of the connection nut 101 is sandwiched between the branch pipe 6 and the outward flange 100b, the connection nut 101 can be prevented from being detached from the joint member 100.

  On the other hand, an annular seal groove 105 surrounding the fuel passage is formed on the upper end surface of each fuel introduction pipe 2, and a seal member 106 is attached to the seal groove 105. A male screw 107 is formed on the outer peripheral surface of the upper end portion of the fuel introduction pipe 2 to be screwed with the female screw 101b of the connecting nut 101.

  Thus, the outward flange 100b of the joint member 100 is overlapped with the upper end surface of the fuel introduction pipe 2 so as to compress the seal member 106, and the non-rotating tool is engaged with the flat portions 100c and 100c on the outer periphery of the cap portion 100a. Then, in a state where the rotation of the joint member 100 is prevented, the connecting nut 101 is rotated and the female screw 101b is screwed into the male screw 107 of the fuel introduction pipe 2 and tightened. 100 outward flanges 100 b can be fastened to the upper end surface of the fuel introduction pipe 2.

  Next, the operation of this embodiment will be described.

  In each fuel injection valve I, when the coil 52 is demagnetized, the needle valve 33 is pressed downward by the urging force of the valve spring 43 and is seated on the valve seat 28. Accordingly, the high-pressure fuel supplied from the fuel pump (not shown) to the fuel distribution pipe D is sent from each branch pipe 6 to the fuel inlet cylinder 45 via the fuel introduction pipe 2, and further inside the pipe-like retainer 42, the fixed core. 26 is sent to the inside of the vertical hole 41, the notch groove 47 of the movable core 37 and the valve seat member 22, and is made to stand by.

  When the coil 52 is energized by energization, the magnetic flux generated by the coil 52 sequentially travels to the coil housing 53, the upper yoke 54, the fixed core 5, the movable core 12, the lower yoke 24, and the coil housing 53. 37 is attracted to the fixed core 26 against the set load of the valve spring 43 and the needle valve 33 is separated from the valve seat 28, so that the high-pressure fuel in the valve seat member 22 flows from the fuel injection hole 23 to the internal combustion engine E. It is directly injected into the corresponding combustion chamber 15.

  At this time, the valve opening stroke of the needle valve 33 is constantly regulated by the stopper flange 36 coming into contact with the lower surface of the stopper plate 27, and between the movable core 37 and the fixed core 26, the contact between them is constant. The minute gap is maintained. Therefore, when the coil 52 is subsequently demagnetized, the residual magnetism between the cores 26 and 37 can be eliminated immediately, and the valve closing response of the needle valve 33 by the valve spring 43 can be enhanced.

  Incidentally, in order to secure the minute gap, as described above, the connecting shaft portion 34a of the needle valve 33 is set so that the distance L1 from the upper surface of the stopper flange 36 to the upper surface of the movable core 37 is L1 = L2−ΔL. Since the adjustment is made by adjusting the press-fitting depth of the movable core 37 into the connecting hole 38, the minute gap can be obtained easily and accurately.

  In addition, the connecting hole 38 of the movable core 37 has a bag shape, and a chip reservoir 40 is defined between the inner end face of the movable core 37 and the connecting shaft portion 34a. By enclosing in the reservoir 40, the chips can be prevented from entering the fuel passage.

  Gaskets 77, 80 arranged vertically with a heat insulating space 79 interposed between a guide cap 18 screwed into the cylinder head 1 of the internal combustion engine E and a mounting cap 70 that holds the valve housing 21 of the fuel injection valve I. Therefore, the gaskets 77 and 80 prevent leakage of the high-pressure gas in the fuel chamber 15 to the guide portion 17, and the heat insulation space 79 prevents high heat from being transferred from the cylinder head 1 to the mounting cap 70. The fuel injection valve I, in particular, the valve seat member 22 and the needle valve 33 can be protected from heat damage.

  Even when rain water, washing water or the like falls on the open side above the guide cylinder 20, the seal ring 88 is fitted on the outer circumference of the closing ring 87 fitted to the outer circumference of the fuel introduction pipe 2 and liquid-tightly laser welded W4. Since the seal ring 88 is liquid-tightly fitted to the inner peripheral surface of the upper end portion of the guide cylinder 20, the seal ring 88 prevents water from entering the guide cylinder 20. Can do.

  In addition, a plurality of seal lips 88c that are in close contact with the outer peripheral surface of the insulation coating of the conductors 61, 61 are formed on the inner peripheral surface of the through holes 93, 93 of the seal ring 88 through the conductors 61, 61 of the fuel injection valve I. 88c are formed, so that the seal lips 88c, 88c,... Can prevent water from entering from the through holes 93, 93 into the guide tube 20.

  Moreover, since the inside of the guide cylinder 20 is open to the atmosphere via the breather tube 97, it is possible to breathe in accordance with the surrounding temperature change, and prevention of dew condensation inside the guide cylinder 20 is achieved.

  In assembling such an in-cylinder fuel injection device, first, the valve seat member 22 of the fuel injection valve I is inserted into the small-diameter cylindrical portion 70a of the mounting cap 70, and the press-fit portion 73 of the connecting cylindrical portion 24a of the lower yoke 24 is inserted. Is pressed into the inner peripheral surface of the large-diameter cylindrical portion 70b of the mounting cap 70, and the upper surface of the large-diameter cylindrical portion 70b on the outer peripheral side from the stress relief groove 74 is brought into contact with the lower surface of the lower yoke 24, To regulate. By such press-fitting, the concentricity between the mounting cap 70 and the valve housing 21 can be ensured. Further, at this time, if an excessive press-fitting load is applied to the press-fit portion, the inner peripheral surface of the large-diameter cylindrical portion 70b is appropriately expanded in diameter toward the stress relief groove 74, thereby causing distortion of the connecting cylindrical portion 24a due to excessive stress, As a result, distortion of the stopper plate 27 and the valve seat member 22 can be prevented, and the characteristics of the fuel injection valve I can be stabilized. Further, since the diameter expansion deformation of the inner peripheral surface of the large diameter cylindrical portion 70b does not reach the outer peripheral side of the stress relief groove 74, the limit of the press fit depth of the press fitting portion 73 and the large diameter cylindrical portion 70b is accurately regulated. , The mutual dimensional accuracy can be improved.

  After that, the small flange 75 of the lower yoke 24 is spread over the entire circumference of the large flange 76 of the mounting cap 70 and integrated with the fillet weld W2 by laser. According to this fillet weld W2, it is possible to weld the large flange 76 and the small flange 75 with relatively little heat input, and the welding heat stays on the small flange 75 and reaches the magnetic path of the lower yoke 24. It doesn't reach.

  In this way, the press-fitted portion of the lower yoke 24 with the mounting cap 70 and the welded portion W2 become the outer portion of the magnetic path of the lower yoke 24, and thus avoid changes in the magnetic properties of the lower yoke 24 due to the press-fit load and welding heat. This can contribute to stabilization of the fuel injection characteristics of the fuel injection valve I.

  Next, the injection valve protection cylinder 3 is fitted to the outer peripheral surface of the small flange 75, the lower end of the injection valve protection cylinder 3 is abutted against the upper surface of the large flange 76 of the mounting cap 70, and the abutment portions thereof. Laser welding W3 is performed over the entire circumference. In this way, the lower yoke 24, the mounting cap 70, and the injection valve protection cylinder 3 are integrated by laser welding W2 and W3, so there is no need to have a protruding portion around them, and the relatively small diameter is obtained. The guide tube 20 and the guide hole 19 can be fitted.

  At this stage, it is visually confirmed whether or not the seal member 83 and the backup ring 84 are properly attached to the seal housing 82 at the upper end portion of the fuel inlet tube 45 from the upper peep hole 85. Further, from the lower viewing hole 65, the identification number or symbol 64 of the fuel injection valve I displayed on the outer surface of the connection portion cover 62 is visually confirmed to prevent erroneous assembly.

  On the other hand, the fuel introduction pipe 2 is attached with a closing ring 87 at a predetermined position by press-fitting and laser welding W4 with reference to the flat portions 110 and 110 on the outer periphery thereof, and a seal ring 88 at a fixed position on the outer periphery of the closing ring 87. Put on.

  Thereafter, the conductors 61 and 61 of the fuel injection valve I are drawn out through the through holes 93 and 93 of the seal ring 88, and the upper part of the conductor protection member 96 that holds the conductors 61 and 61 is closed below the seal ring 88. Engage with the notch 92 in the ring 87.

  Next, the fuel introduction pipe 2 is inserted into the injection valve protection cylinder 3, and the lower end portion of the fuel introduction pipe 2 is fitted to the outer periphery of the upper end portion of the fuel inlet cylinder 45 so that the seal member 83 is in close contact with the inner peripheral surface thereof. At the same time, the closing ring 87 is fitted into the upper end portion of the injection valve protection cylinder 3, and the lower part of the conductor protection member 96 is engaged with the notch 91 of the injection valve protection cylinder 3. That is, after determining the relative positions around the axis of the closing ring 87 and the injection valve protection cylinder 3 via the conductor protection member 96, the conductors 61, 61 in the injection valve protection cylinder 3 are loosened. 61, 61 is pulled upward, and the injection valve protection cylinder 3 and the closing ring 87 are laser-welded W5. As described above, since the closing ring 87 and the injection valve protection cylinder 3 are integrated by laser welding W5, it is not necessary to have an overhanging portion around them, and it is possible to fit the guide cylinder 20 with a relatively small diameter. Become.

  Next, as described above, the outward flange 100b of the joint member 100 connected to each branch pipe 6 is abutted against the upper end surface of the fuel introduction pipe 2 with the seal member 106 interposed therebetween, and the flat portion 100c on the outer periphery of the cap portion 100a, In a state where the rotation stop tool is engaged with 100c to prevent the rotation of the joint member 100, the connecting nut 101 is screwed into the male screw 107 of the fuel introduction pipe 2 and tightened, whereby the joint member 100 and the fuel introduction pipe 2 are connected. Connect to each other.

  Thus, the branch pipe 6 can be communicated with the fuel introduction pipe 2 through the joint member 100, and fuel leakage from the butted surfaces of the joint member 100 and the fuel introduction pipe 2 is prevented by the seal member 106. be able to. In particular, when the coupling nut 101 is screwed into the male screw 107 and tightened, the rotation of the joint member 100 can be surely prevented by the anti-rotation tool engaged with the flat portions 100c and 100c on the outer periphery of the cap portion 100a. 100 and the fuel introduction pipe 2 are reliably prevented from rotating with each other, and the seal member 106 interposed therebetween is not twisted, so that it is not damaged and can always exhibit a good sealing function. The occurrence of distortion in the branch pipe 6 of the fuel distribution pipe D connected to the joint member 100 can be suppressed, which can contribute to ensuring high quality. In addition, since the fuel introduction pipe 2 and the joint member 100 can be easily connected to each other with the nut 101 without using a special bolt having a fuel passage, the connection structure can be configured at low cost.

  Thus, in the fuel distribution pipe D, a plurality of injection valve protection cylinders 3, 3 ... holding the fuel injection valves I, I ... are suspended through the plurality of branch pipes 6, 6 ... A plurality of injection valve protection cylinders 3, 3... Are inserted into a plurality of guide portions 17, 17... Including a guide cap 18 and a guide cylinder 20 provided corresponding to each cylinder on the internal combustion engine E side. Gaskets 77 and 80 are sandwiched between 18 and the mounting cap 70, and the outer peripheral seal lip 88 b of each seal ring 88 is brought into close contact with the inner peripheral surface of the guide cylinder 20. Finally, the plurality of brackets 7, 7... Of the distribution pipe body 5 are fixed to the plurality of mounting portions 8, 8.

  In this way, an assembly of the fuel injection valve I, the injection valve protection cylinder 3 and the fuel introduction pipe 2 is pre-configured outside the internal combustion engine E, and the assembly is connected to each of the plurality of branch pipes 6 of the fuel distribution pipe D. By suspending, a plurality of the above assemblies can be attached to the cylinder head 1 at the same time, and the assemblability can be greatly improved. Moreover, since the fuel passage constituent members such as the fuel introduction pipe 2 and the branch pipe 6 of the fuel distribution pipe D are used for the suspension of the assemblies, the suspension structure is simple.

  At this time, each branch pipe 6 is applied with stress for clamping the gaskets 77 and 80 between the guide caps 18 and the mounting caps 70, thereby suppressing vibration of the injection valve protection cylinder 3 and fuel injection. The concentricity of the valve I and the guide cylinder 20 can be ensured, and the fuel injection direction of the fuel injection valve I can be made constant. Therefore, it is not necessary to directly fix the injection valve protection cylinder 3 to the guide cylinder 20, and the assembling property can be further improved.

  In addition, the fuel injection valve I is accommodated and held in the mounting cap 70 and the valve seat member 22 is stored in the injection valve protection cylinder 3 to which the mounting cap 70 is coupled, that is, only the lower end portion is supported by the mounting cap 70. Therefore, even when an attachment load is applied to the attachment cap 70 and the injection valve protection cylinder 3 when the assembly is attached to the cylinder head 1, it is understood that the load acts on the fuel injection valve I. This can be prevented by the valve protection cylinder 3, and therefore, the fuel injection valve I does not generate unnecessary stress, so that stable fuel injection characteristics can always be exhibited.

  On the other hand, when the brackets 7, 7... Are removed from the mounting portions 8, 8... And the fuel distribution pipe D is pulled up, a plurality of injection valve protection cylinders 3, 3,. Can be drawn all at once from the guide portions 17, 17.

  The present invention is not limited to the above embodiment, and various design changes can be made without departing from the scope of the invention.

The side view of the cylinder fuel injection apparatus of the internal combustion engine which concerns on the Example of this invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. FIG. 4 is a sectional view taken along line 4-4 of FIG. FIG. 5 is an enlarged view of part 5 of FIG. 4. FIG. 6 is an enlarged view of 6 parts in FIG. 4. FIG. 7 is an enlarged view of part 7 of FIG. 4. FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 5. FIG. 9 is a view of the fuel injection valve in FIG. FIG. 10 is a sectional view taken along line 10-10 in FIG. 9; The perspective view of the gasket in FIG. The perspective view of the backup ring in FIG. The longitudinal cross-sectional view of the seal ring in FIG. The perspective view of the conducting wire protection member of FIG.

Explanation of symbols

D ... Fuel distribution pipe E ... Internal combustion engine I ... Fuel injection valve 1 ... Engine body (cylinder head)
2 ... Fuel introduction pipe 6 ... Branch pipe 15 ... Combustion chamber 23 ... Fuel injection hole 45 ... Fuel inlet tube 100 ... Joint member 100a ... cap part 100b ... outward flange 100c ... plane part 101 ... connection nut 101c ... inward flange 106 ... seal member 107 ... male screw

Claims (2)

An electromagnetic fuel injection valve (I) that opens a fuel injection hole (23) to inject fuel directly into the combustion chamber (15) of the engine body (1), and the fuel injection hole of the fuel injection valve (I) A fuel introduction pipe (2) connected to a fuel inlet cylinder (45) extending on the opposite side of (23), and a fuel distribution pipe (D) connected to the fuel introduction pipe (2) via a joint member (100) In-cylinder fuel injection device for an internal combustion engine,
The joint member (100) has a cap portion (100a) whose inside is communicated with the fuel distribution pipe (D) and has one end surface opened, and is provided on the outer periphery of the open end of the cap portion (100a). It is composed of an outward flange (100b) superimposed on the outer end of the introduction pipe (2) via a seal member (106), while the fuel introduction pipe (2) is adjacent to the outward flange (100b). A male screw (107) is formed on the outer periphery of the end portion, and the outward flange (10b) accompanying the screwing is connected to the connecting nut (101) screwed to the male screw (107). An in-cylinder fuel injection device for an internal combustion engine, characterized in that an inward flange (101c) that presses against the internal combustion engine is formed. The in-cylinder fuel injection device for an internal combustion engine according to claim 1,
An in-cylinder fuel injection device for an internal combustion engine, characterized in that an engaging flat portion (100c) for a non-rotating tool is formed on an outer peripheral surface of the cap portion (100a).

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