JP4937891B2 - Fuel supply device - Google Patents

Description

  The present invention relates to a fuel supply device for an internal combustion engine.

A conventional example will be described. FIG. 8 is a block diagram showing the fuel supply device.
As shown in FIG. 8, the fuel supply device 100 includes an injector 117 that injects fuel into an intake passage 115 formed in the intake manifold 114, and a delivery pipe 123 that supplies fuel to the injector 117. The delivery pipe 123 is attached to the intake manifold 114 with bolts 134. Note that a fuel supply apparatus such as the conventional example is described in Patent Document 1, for example.

JP 2003-193944 A

In the fuel supply device 100 of the conventional example, the delivery pipe 123 is directly attached to the intake manifold 114 with bolts 134. For this reason, heat on the internal combustion engine 110 side (engine side) is transmitted from the intake manifold 114 to the delivery pipe 123 or from the intake manifold 114 to the delivery pipe 123 via the bolt 134, thereby There was a problem that the fuel was easily heated. This is not preferable because, for example, in the case of a fuel that is easily vaporized, such as liquefied petroleum gas (LPG), the restartability deteriorates due to the vaporization of the fuel.
An object of the present invention is to provide a fuel supply device capable of preventing heat transfer from an internal combustion engine side to a piping member via an intake passage forming member and an attachment member.

The above-mentioned problems can be solved by a fuel supply apparatus having the gist of the configuration described in the claims of the present invention.
That is, according to the fuel supply device described in claim 1 of the claims, the heat insulating properties are respectively provided between the joint portion between the intake passage forming member and the piping member and between the joint portion between the piping member and the mounting member. The heat insulation member which has is interposed. Therefore, since the piping member is thermally insulated from the intake passage forming member and the mounting member by the heat insulating member, heat transfer from the internal combustion engine side to the piping member via the intake passage forming member and the mounting member is prevented or reduced. Can do.
Further, the injector has a fuel inlet for introducing fuel and a fuel outlet for discharging excess fuel, and the piping member is a delivery pipe through which fuel supplied to the injector flows and communicates with the fuel inlet. And a return pipe through which excess fuel flowing out from the fuel outlet of the injector flows.
Further, the intake passage forming member is formed with a recess corresponding to the tip of the injector, and a fuel injection passage penetrating from the recess to the intake passage, and has heat insulation in the recess. An insulator having a guide tube inserted into the fuel injection passage is fitted, a tip surface having a nozzle hole for injecting fuel of the injector is brought into contact with the insulator, and the nozzle hole is aligned with the guide tube of the insulator; The fuel injected from the injector nozzle is injected into the intake passage through the guide tube of the insulator.

  Moreover, according to the fuel supply device described in claim 2 of the claims, the injector is floatingly supported by the piping member via the support member having a heat insulating property. Accordingly, since the injector is insulated from the piping member via the support member, heat transfer from the piping member to the injector can be prevented or reduced.

  Further, according to the fuel supply device described in claim 3 of the claims, when the pipe member and the heat insulating member are bonded to each other with the adhesive in a state of being fitted to each other, An at least one fitting surface is provided with an escape recess for allowing excess adhesive to escape. Therefore, it is possible to prevent or reduce the excess of the adhesive from protruding between the joint surfaces of both members. As a result, the attachment accuracy of the heat insulating member with respect to the piping member can be improved.

According to the fuel supply device of the fourth aspect of the present invention , the return pipe is provided with the attached portion of the piping member that is attached to the intake passage forming member by the attachment member. As a result, heat transfer from the internal combustion engine side to the return pipe is prevented or reduced, so that an increase in the temperature of excess fuel flowing through the return pipe can be suppressed.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  An embodiment of the present invention will be described with reference to the drawings. In this embodiment, a fuel supply device that injects and supplies liquefied petroleum gas (LPG) as fuel to an internal combustion engine is illustrated. 1 is a front view showing the fuel supply device, FIG. 2 is a plan view, FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 5 is a cross-sectional view taken along line VV in FIG. The internal combustion engine (not shown) is a multi-cylinder internal combustion engine (for example, three cylinders, four cylinders, six cylinders, etc.) arranged in series, but the number of cylinders and the arrangement mode are not limited.

  As shown in FIG. 3, the cylinder head 11 of the internal combustion engine is formed with intake ports 12 corresponding to the number of cylinders. An intake manifold 14 having an intake passage 15 communicating with each intake port 12 is fastened to the cylinder head 11 through a heat-insulating gasket 16 and a metal spacer 13 such as an aluminum alloy having good thermal conductivity. Has been. The gasket 16 and the spacer 13 are formed with a series of communication holes (not shown) that communicate the intake passage 15 of the intake manifold 14 and the intake port 12 of the cylinder head 11. As is well known, a surge tank, an air cleaner and the like (not shown) are connected to the upstream side of the intake manifold 14. Accordingly, the intake air is sucked into the intake port 12 from the air cleaner through the surge tank and the intake manifold 14. The cylinder head 11 and the intake manifold 14 correspond to an “intake passage forming member” in this specification. The intake passage 15 of the intake manifold 14, the intake port 12 of the cylinder head 11, the gasket 16 and the communication holes of the spacer 13 correspond to the “intake passage” in this specification.

As shown in FIG. 1, in order to mount a fuel supply device 23 (described later) on the intake manifold 14, it is positioned between adjacent cylinders on the cylinder head 11 side end of the intake manifold 14. The mounting convex part 17 protrudes. A female screw hole 17a is concentrically formed in the mounting convex portion 17 (see FIG. 5). Further, as shown in FIG. 3, an injector pedestal 18 corresponding to each cylinder is formed on the end of the intake manifold 14 on the cylinder head 11 side. A stepped hole-like recess 18 a is formed on the upper surface of the pedestal 18. A series of straight fuel injection passages 19 that are concentric and pass through the pedestal 18, gasket 16, spacer 13, and cylinder head 11 are formed on the lower surface side of the recess 18a (see FIG. 1). . A downstream end of the fuel injection passage 19 is opened in the inner wall surface of the intake port 12 of the cylinder head 11. Note that the metal spacer 13 with good thermal conductivity uses the heat of the internal combustion engine to bring the temperature around the opening of the fuel injection passage 19 to a high temperature. When the downstream end of the fuel injection passage 19 is opened to the hole wall surface of the communication hole of the spacer 13 instead of the inner wall surface of the intake port 12 of the cylinder head 11, the fuel injection passage 19 is provided in the cylinder head 16. There is no need.

  As shown in FIG. 3, when a fuel supply device 23 (described later) is mounted on the intake manifold 14, the first insulator 20 made of rubber having heat insulation is fitted in the recess 18a. To do. A guide tube 21 to be inserted into the fuel injection passage 19 is fixed to the central portion of the first insulator 20. Moreover, the 1st insulator 20 has integrally the main part 20a fitted in the recessed part 18a, and the annular | circular shaped seal part 20b which protrudes on the outer peripheral part of the main part 20a.

Next, a fuel supply device 23 for supplying fuel (LPG) to the internal combustion engine will be described.
As shown in FIG. 3, the fuel supply device 23 includes a fuel injection valve, that is, an injector 24 that injects fuel into the intake port 12 of the cylinder head 11, and a piping member 25 through which the fuel applied to the injector 24 flows. Yes.

  The injector 24 will be described. As shown in FIG. 3, the injector 24 is controlled by an electronic control unit (ECU) (not shown), and injects pressurized fuel supplied from a fuel pump into the intake port 12. In the embodiment, a bottom feed type electromagnetic injector called bottom return is used for bottom feed. As is well known, the injector 24 has a fuel inlet 28 that opens to the outer surface near the tip end portion (lower end portion in FIG. 3) of the injector body 27, and opens to the tip end surface (lower end surface) of the injector body 27. And a fuel outlet 30 that opens to the upper end surface of the injector body 27. The fuel introduced from the fuel inlet 28 into the injector body 27 is injected from the nozzle 29 when the solenoid coil (not shown) in the injector body 27 is opened. Further, of the fuel introduced into the injector body 27, the remaining fuel that is not injected from the injection port 29 flows out from the fuel outlet 30 as surplus fuel.

  A power receiving connector 31 protrudes from the upper side surface of the injector body 27 near the center. Further, a lower flange portion 31 b located below the base portion 31 a of the power receiving connector 31 protrudes from the outer peripheral surface of the injector body 27. A small-diameter shaft portion (not shown) that reduces the outer diameter is formed below the lower flange portion 31b, and a third insulator 32 made of rubber having heat insulation is fitted to the small-diameter shaft portion. Has been. Note that the outer diameter of the third insulator 32 is substantially equal to the outer diameter of the flange portion 31b.

  The injector body 27 has a plurality of (for example, mainly four) shaft portions 33 to 36 concentrically projected in a stepwise manner so as to gradually decrease in diameter downward from the lower flange portion 31b. Have. Further, an upper flange portion 38 located above the base portion 31 a of the power receiving connector 31 projects from the outer peripheral surface of the injector body 27. Further, the injector body 27 has a connecting shaft portion 39 projecting on the upper flange portion 38 concentrically. And the shaft part 35 in the second stage from the lowermost stage is provided with the fuel inlet 28 on its side surface. Further, the lowermost shaft portion 36 includes the nozzle hole 29 on the lower end surface thereof. Further, the connection shaft portion 39 includes the fuel outlet 30 on the upper end surface thereof.

  A first O-ring (O-ring) 41 having heat insulating properties is disposed on the shaft portion 34 in the third step from the lowermost step. A second O-ring 42 that is located below the fuel inlet 28 and has heat insulation properties is disposed on the shaft portion 35 that is second from the bottom. The connection shaft portion 39 is provided with a third O-ring 43 having a heat insulating property. These O-rings 41, 42, and 43 are attached to an annular groove formed on the outer peripheral surface of the shaft portion using elasticity. Further, on the upper flange portion 38, a second insulator 44 made of rubber that is fitted to the connection shaft portion 39 and has heat insulation properties is disposed. The O-rings 41, 42, 43 and the second insulator 44 correspond to the “support member” in this specification.

  As shown in FIGS. 1 and 2, the piping member 25 includes a delivery pipe 46 through which fuel supplied to each injector 24 (see FIG. 3) provided for each cylinder of the internal combustion engine flows, and each injector 24. A return pipe 47 through which surplus fuel returned from the fuel flows, and injector covers 48 corresponding to the number of cylinders that respectively flow the fuel from the delivery pipe 46 to the injectors 24 and support the injectors 24. Has been. Hereinafter, for convenience of explanation, the injector cover 48, the delivery pipe 46, and the return pipe 47 will be described in this order.

  The injector cover 48 will be described. As shown in FIG. 4, the injector cover 48 includes a cover portion 50 formed in a hollow cylindrical shape into which the injector 24 can be inserted from above, and a triangular trapezoidal delivery projecting to the front side (right side in FIG. 3). And a pipe mounting base 51. A cutout portion 52 for receiving the power receiving connector 31 of the injector 24 is formed in the upper portion of the rear side (left side in FIG. 3) of the cover portion 50. Further, a stepped stopper portion 53 with which the third insulator 32 abuts is formed on the inner peripheral surface of the cover portion 50. The stopper portion 53 is continuous with the lower end surface of the cutout portion 52. Further, the lower end portion of the lowermost shaft portion 36 of the injector 24 protrudes from the lower end opening surface of the cover portion 50 in a state where the third insulator 32 is in contact with the stopper portion 53. A flange portion 54 projects from the outer peripheral surface of the lower end portion of the cover portion 50. The flange portion 54 can come into contact with the seal portion 20b of the first insulator 20 disposed in the intake manifold 14. Further, on the inner peripheral surface of the cover portion 50, a large diameter hole portion 55 with which the first O-ring 41 of the injector 24 abuts elastically, and an injector positioned below the large diameter hole portion 55 A small-diameter hole portion 56 with which the 24 second O-rings 42 are elastically contacted is formed.

  When the injector 24 is inserted into the cover portion 50 from above, the power receiving connector 31 is received in the cutout portion 52, and the third insulator 32 comes into contact with the stopper portion 53. Thus, the insertion position of the injector 24 with respect to the cover unit 50 is defined. At the same time, the third insulator 32 is elastically sandwiched between the lower flange portion 31b of the injector 24 and the stopper portion 53 of the cover portion 50 (see FIGS. 3 and 4). Further, the first O-ring 41 is elastically brought into contact with the inner peripheral surface of the large-diameter hole portion 55 of the cover portion 50, thereby sealing between the two. At the same time, the second O-ring 42 is brought into elastic contact with the inner peripheral surface of the small-diameter hole portion 56 so that the space between the two is sealed. As a result, an annular space portion 57 that communicates with the fuel inlet 28 of the injector 24 and surrounds the shaft portion 35 having the fuel inlet 28 is formed between the O-rings 41 and 42 in the large-diameter hole portion 55 of the cover portion 50. Will be formed. In addition, the injector 24 is floatingly supported in the cover portion 50 via both O-rings 41 and 42 and the third insulator 32.

  As shown in FIG. 3, the mounting base 51 is formed with a fuel introduction passage 59 that opens in the lower inner peripheral surface of the large-diameter hole 55 of the cover 50 and penetrates linearly toward the front upper side. Has been. A lower end portion of the fuel introduction passage 59 communicates with the annular space portion 57. As shown in FIG. 4, a pair of left and right mounting pieces 60 projecting in the opposite directions are provided at the upper end portion of the cover portion 50.

  Next, the delivery pipe 46 will be described. As shown in FIGS. 1 and 2, the delivery pipe 46 is provided between a relay union 63 fastened to the mounting base 51 of each injector cover 48 by a fixing bolt 62 and an adjacent relay union 63. A horizontal tube 64 that communicates with each other, and a connection-side tube 65 that communicates a relay union 63 on one end side (left end side in FIG. 1) and a fuel supply pipe (not shown) that communicates with a fuel tank are provided. Further, the fuel supplied into each relay union 63 via the connection side tube 65 and the horizontal tube 64 is introduced into the fuel of the injector cover 48 via a communication path (not shown) provided in the fixing bolt 62. It is supplied to the passage 59. A series of passage portions formed in the delivery pipe 46 is a fuel supply passage through which fuel supplied from a fuel pump (not shown) flows.

  Next, the return pipe 47 will be described. As shown in FIGS. 1 and 2, the return pipe 47 is formed in a hollow pipe shape extending in the cylinder row direction (left and right direction in FIGS. 1 and 2). On the lower side of the return pipe 47, connecting portions 70 respectively corresponding to the injectors 24 (see FIG. 4) for the cylinders are provided. A hollow cylindrical connection hole 71 is formed in the central portion of the connection portion 70 so as to communicate with the hollow portion in the return pipe 47 and into which the connection shaft portion 39 of the injector 24 can be inserted (see FIG. 4). A pair of left and right protrusions 70 a corresponding to the left and right attachment pieces 60 of the injector cover 48 protrude from the lower surface side of the connection portion 70.

  As shown in FIGS. 3 and 4, the connecting shaft portion 39 of the injector 24 attached to the injector cover 48 is relatively inserted into the connecting hole 71 of the connecting portion 70. Along with this, the third O-ring 43 of the injector 24 is elastically brought into contact with the inner peripheral surface of the connection hole 71 to seal the two. As shown in FIG. 4, the return pipe 47 and the injector cover 48 are integrated with each other by fastening the attachment pieces 60 of the injector cover 48 to the projections 70a with the attachment bolts 72, respectively. The Further, the second insulator 44 is elastically sandwiched between the hole edge portion of the connection hole 72 on the lower surface of the connection portion 70 and the flange portion 38 on the upper side of the injector 24 opposed thereto (FIGS. 3 and 4). reference). Therefore, the injector 24 is floatingly supported with respect to the return pipe 47 via the third O-ring 43 and the second insulator 44. As a result, the injector 24 passes through the first to third O-rings 41 to 43, the second insulator 44, and the third insulator 32 with respect to the piping member 25 (specifically, the return pipe 47 and the injector cover 48). Will be supported floating. In the hollow portion of the return pipe 47, there is an excess fuel passage 74 through which excess fuel returned from the fuel outlet 30 of the injector 24 flows. The return pipe 47 is connected to the fuel tank via a return path provided separately from the fuel supply path including the delivery pipe 46.

  As shown in FIG. 2, at both left and right end portions of the return pipe 47, a cylindrical portion 76 having a hollow cylindrical shape located between adjacent connecting portions 70 is provided. The axis of each cylindrical portion 76 is parallel to the axis of the injector 24. Further, the cylindrical portions 76 at both left and right end portions are provided in a protruding shape with a pair of front and rear on the front and rear sides (up and down in FIG. 2) of the return pipe 47. It should be noted that the pair of front and rear cylindrical portions 76 are formed with a positional relationship slightly shifted in the left-right direction, and the two left and right sets of cylindrical portions are symmetrical. Further, the mounting projections 17 are provided on the intake manifold 14 so as to correspond to the left and right sets of cylindrical portions 76 (see FIG. 1).

  As shown in FIG. 5, the 1st spacer 78 which makes | forms the resin-made ring shape which has heat insulation is adhere | attached on the upper side of the said cylindrical part 76 with the adhesive agent. A second spacer 80 having a heat-insulating resin hollow cylindrical shape is bonded to the lower side of the cylindrical portion 76 with an adhesive. As described above, according to the piping member 25 in which the spacers 78 and 80 are bonded to the cylindrical portion 76, the operation of arranging the spacers 78 and 80 when mounting on the intake manifold 14 can be omitted. The cylindrical portion 76 corresponds to the “attached portion” in this specification. The first spacer 78 and the second spacer 80 correspond to the “heat insulating member” in this specification.

  The cylindrical portion 76 provided with both the spacers 78 and 80 is aligned with the mounting convex portion 17 of the intake manifold 14 when the piping member 25 is disposed on the intake manifold 14. Then, by fastening the fixing bolt 82 through the hollow portion of the cylindrical portion 76 and the hollow portion of the second spacer 80 from the hollow portion of the first spacer 78 to the female screw hole 17a of the mounting convex portion 17, A return pipe 47 is fastened on top. As a result, the piping member 25 is fixed on the intake manifold 14. The fixing bolt 82 corresponds to an “attachment member” in this specification.

  Therefore, the first spacer 78 is interposed between the joint portion between the tubular portion 76 of the return pipe 47 of the piping member 25 and the head portion 82a of the fixing bolt 82, and the tubular portion 76 and the intake manifold 14 (details). The second spacer 80 is interposed between the joints with the mounting projection 17). Accordingly, the flange portion 54 of the injector cover 48 is elastically brought into contact with the seal portion 20b of the first insulator 20 provided in the intake manifold 14, thereby sealing between the two ( 3 and 4). At the same time, the tip end surface of the lowermost shaft portion 36 of the injector 24 is elastically brought into contact with the main portion 20 a of the first insulator 20 of the intake manifold 14, so that the nozzle hole 29 is in the first insulator 20. The guide tube 21 is aligned. Therefore, since the injector 24 and the injector cover 48 are thermally insulated from the intake manifold 14 via the first insulator 20, heat transfer from the intake manifold 14 to the injector 24 and the injector cover 48 can be prevented or reduced. .

  The first spacer 78 and the second spacer 80 have an inner diameter that allows the shaft portion 82b of the fixing bolt 82 to be inserted almost without shaking. The cylindrical portion 76 has an inner diameter that allows the shaft portion 82b of the fixing bolt 82 to be loosely inserted and forms an annular gap 83 that surrounds the shaft portion 82b. Therefore, since the cylindrical part 76 and the shaft part 82b of the fixing bolt 82 are separated from each other, it is avoided that the heat on the shaft part 82b side is directly transmitted to the cylindrical part 76 side.

  Thus, the first spacer 78 and the second spacer 80 are concentrically aligned with each other by fitting the cylindrical portion 76 with the fitting structure described below. In addition, since the fitting structure of the spacers 78 and 80 with respect to the cylindrical portion 76 is vertically symmetrical, the fitting structure of the first spacer 78 will be described, and the fitting of the second spacer 80 will be described. The description of the structure is omitted by giving the same reference numerals to the same parts. FIG. 6 is an exploded cross-sectional view of the spacer mounting structure for the cylindrical portion of the return pipe.

  As shown in FIG. 6, a cylindrical fitting convex portion 84 is projected from the lower surface of the first spacer 78 along the inner peripheral portion thereof. A stepped hole-shaped fitting recess 86 into which the fitting protrusion 84 can be fitted is formed at the upper end opening of the cylindrical portion 76. Therefore, by fitting the fitting convex portion 84 and the fitting concave portion 86, the cylindrical portion 76 and the first spacer 78 can be aligned concentrically. The fitting recess 86 is formed with an inner diameter larger than the inner diameter of the cylindrical portion 76.

  Further, when the fitting convex portion 84 and the fitting concave portion 86 are fitted to each other when the cylindrical portion 76 and the first spacer 78 are bonded to each other, the gap between the joint surfaces (the upper end surface of the cylindrical portion 76 and its surface) The excess of the adhesive may protrude between the first spacer 78 and the lower surface of the first spacer 78 joined to the cylindrical portion 76, and the mounting accuracy of the first spacer 78 on the cylindrical portion 76 may be reduced. For this reason, an escape recess 87 formed of an annular groove continuous in the circumferential direction is formed on the fitting surface of the fitting recess 86 with respect to the fitting convex portion 84, that is, the inner peripheral surface. Therefore, as shown in FIG. 5, the surplus amount 88 of the adhesive due to the fitting between the fitting convex portion 84 and the fitting concave portion 86 can be released into the relief concave portion 87, and the gap between the joint surfaces between the two can be reduced. The protrusion of the adhesive can be prevented or reduced.

  Further, since the second spacer 80 is fitted to the mounting convex portion 17 of the intake manifold 14 with the fitting structure of the fitting convex portion 84 and the fitting concave portion 86, the same portion. The description will be omitted by attaching the same reference numerals to. However, since the second spacer 80 and the mounting projection 17 are not bonded, the relief recess 87 is omitted.

  In the fuel supply device 23 (see FIGS. 1 to 4), fuel in a fuel tank (not shown) is supplied to the delivery pipe 46 by a fuel pump through a fuel supply path. The fuel supplied to the delivery pipe 46 is introduced into the annular space 57 through the fuel introduction passage 59 of the injector cover 48 (see FIG. 3). The injector 24 injects the fuel introduced into the injector body 27 from the annular space 57 via the fuel inlet 28 into the intake port 12 of the cylinder head 11 through the guide tube 21 of the first insulator 20 from the injection port 29. . The injected fuel merges with the intake air introduced into the intake port 12 from the intake passage 15 of the intake manifold 14. Further, the fuel remaining without being injected from the injection hole 29 of the injector 24 flows out into the excess fuel passage 74 through the connection hole 71 of the return pipe 47 as excess fuel from the fuel outlet 30 (see FIG. 4). The surplus fuel is returned to the fuel tank from the surplus fuel passage 74 via the return path.

  According to the fuel supply device 23, the second heat-insulating property is provided between the joint portion between the intake manifold 14 and the piping member 25, that is, between the joint portion 17 of the intake manifold 14 and the tubular portion 76 of the return pipe 47. The spacer 80 is interposed, and a first spacer 78 having heat insulation is interposed between the joint portion between the cylindrical portion 76 and the head portion 82 a of the fixing bolt 82. Accordingly, the cylindrical portion 76 of the return pipe 47 is thermally insulated from the mounting convex portion 17 of the intake manifold 14 and the head portion 82a of the fixing bolt 82 by the spacers 78 and 80, respectively. Heat transfer transmitted to the return pipe 47 of the piping member 25 through the fixing bolt 82 can be prevented or reduced. This is effective for improving the restartability by suppressing the vaporization of the fuel in the case of a fuel that is easily vaporized such as liquefied petroleum gas (LPG).

  In addition, the injector 24 supports the cover 50 of the injector cover 48 of the piping member 25 and the connection 70 of the return pipe 47 via the O-rings 41 to 43 and the second insulator 44 having heat insulation. (See FIG. 3 and FIG. 4). Accordingly, since the injector 24 is insulated from the injector cover 48 and the return pipe 47 through the O-rings 41 to 43 and the second insulator 44, heat transfer from the injector cover 48 and the return pipe 47 to the injector 24 is prevented. Alternatively, it can be reduced.

  Further, when the tubular portion 76 of the return pipe 47 and the first spacer 78 and the second spacer 80 are fitted to each other with an adhesive, the fitting surface of the tubular portion 76, that is, the inner peripheral surface. In addition, an escape recess 87 is provided for allowing excess adhesive 88 to escape (see FIG. 5). Accordingly, it is possible to prevent or reduce the excess adhesive 88 from protruding between the joining surfaces of the cylindrical portion 76 and the first spacer 78 and the second spacer 80. As a result, the attachment accuracy of the 1st spacer 78 and the 2nd spacer 80 with respect to the cylindrical part 76 can be improved.

  Further, the attached portion of the piping member 25 attached to the intake manifold 14 by the fixing bolt 82, that is, the cylindrical portion 76 is provided in the return pipe 47 through which the surplus fuel returned from the injector 24 flows (see FIG. 5). . As a result, heat transfer from the internal combustion engine side to the return pipe 47 is prevented or reduced, so that an increase in the temperature of the surplus fuel in the return pipe 47, that is, the surplus fuel passage 74, can be suppressed.

The present invention is not limited to the above-described embodiments, and modifications can be made without departing from the gist of the present invention. For example, the fuel is not limited to LPG, and liquefied natural gas, engine fuel such as gasoline and light oil, and other fuels are applicable. The injector 24 is not limited to the one that injects fuel into the intake port 12 of the cylinder head 11 but may be one that injects fuel into the intake passage 15 of the intake manifold 14 or the combustion chamber of the internal combustion engine. The injector 24 is not limited to the bottom feed type, and a top feed type electromagnetic injector may be used. Further, the mounting member is not limited to the fixing bolt 82 of the above embodiment, and it is also possible to use a rivet, a clip or the like.

  In the above embodiment, the relief recess 87 is provided on the inner peripheral surface of the fitting recess 86. However, as shown in FIG. The relief recess 87 may be provided on both the outer peripheral surface of the fitting convex portion 84 and the inner peripheral surface of the fitting concave portion 86. Further, the relief recess 87 is not limited to an annular groove that is continuous in the circumferential direction, and may be any shape that can escape the excess of the adhesive, and its shape, number, and arrangement are not limited. . Further, the fitting convex portion 84 and the fitting concave portion 86 may be reversely arranged, that is, the fitting convex portion 84 may be provided in the cylindrical portion 76, and the fitting concave portion 86 may be provided in the spacers 78 and 80.

It is a front view which shows the fuel supply apparatus concerning one Example. It is a top view which shows a fuel supply apparatus. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. It is a VV arrow directional cross-sectional view of FIG. It is sectional drawing which decomposes | disassembles and shows the attachment structure of the spacer with respect to the cylindrical part of a return pipe. It is sectional drawing which shows another example of the attachment structure of the spacer with respect to the cylindrical part of a return pipe. It is a block diagram which shows the fuel supply apparatus concerning a prior art example.

Explanation of symbols

11 Cylinder head (intake path forming member)
12 Intake port (intake path)
14 Intake manifold (intake channel forming member)
15 Intake passage (intake passage)
17 Mounting convex portion 23 Fuel supply device 24 Injector 25 Piping member 41 First O-ring (supporting member)
42 Second O-ring (supporting member)
43 Third O-ring (supporting member)
44 Second insulator (supporting member)
48 Injector cover 50 Cover part 76 Cylindrical part (attached part)
78 First spacer (heat insulation member)
80 Second spacer (heat insulation member)
82 Fixing bolt (mounting member)
84 Fitting convex part 86 Fitting concave part 87 Relief concave part

Claims (4)

An injector for injecting fuel into an intake passage formed in the intake passage forming member;
A piping member through which the fuel applied to the injector flows,
A fuel supply device in which the piping member is attached to the intake passage forming member by an attachment member,
Between the joint portion between the intake passage forming member and the piping member, and between the joint portion between the piping member and the mounting member, respectively, a heat insulating member having heat insulation is interposed,
The injector has a fuel inlet for introducing fuel and a fuel outlet for discharging excess fuel,
The piping member includes a delivery pipe through which fuel supplied to the injector flows and communicates with the fuel inlet, and a return pipe through which surplus fuel flowing out from the fuel outlet of the injector flows ,
The intake passage forming member is formed with a recess corresponding to the tip of the injector, and a fuel injection passage penetrating from the recess to the intake passage.
An insulator having a heat insulating property and having a guide tube inserted into the fuel injection passage is fitted in the recess,
A tip surface having a nozzle for injecting fuel of the injector is brought into contact with the insulator, and the nozzle is aligned with a guide tube of the insulator;
A fuel supply device characterized in that fuel injected from the injection port of the injector is injected into the intake passage through a guide tube of the insulator . The fuel supply device according to claim 1,
The fuel supply apparatus according to claim 1, wherein the injector is floatingly supported by the piping member via a support member having heat insulation properties. The fuel supply device according to claim 1 or 2,
When bonding the pipe member and the heat insulating member with an adhesive in a state of being fitted to each other, the excess of the adhesive is released to at least one of the fitting surfaces of the two members. A fuel supply device provided with a relief recess. The fuel supply device according to any one of claims 1 to 3,
The fuel supply device according to claim 1, wherein an attachment portion of the piping member attached to the intake passage forming member by the attachment member is provided in the return pipe.

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