JP2007177766A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve combustion by inhibiting deposition of deposit to an injection hole in a fuel injection device. <P>SOLUTION: In the fuel injection device, an injection hole plate 43 having the injection holes 44a, 44b, 44c formed thereon is fixed on a tip part of a valve body 42 of an injector 33, a needle valve 48 is movably supported in the valve body 42, the needle valve 48 establishes communication of a fourth fuel passage 62 and the injection holes 44a, 44b, 44c and enables to inject fuel to a combustion chamber 16, and the injection holes 44a, 44b, 44c consists of restriction parts 71a, 71b, 71c communicating to the fourth fuel passage 62 and having tapered shape passage diameter, and expansion parts 72a, 72b, 72c having passage diameters larger than the restriction parts 71a, 71b, 71c and constant in an axial direction and communicating to the combustion chamber 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection device capable of injecting a predetermined amount of fuel.

  2. Description of the Related Art Conventionally, a direct injection internal combustion engine that directly injects fuel into a combustion chamber instead of an intake port is known. In this cylinder injection type internal combustion engine, when the intake valve is opened, air is drawn into the combustion chamber from the intake port and compressed by the piston, and fuel is directly injected from the fuel injection device to the high-pressure air. Then, high-pressure air and mist-like fuel are mixed in the combustion chamber, and this air-fuel mixture is led to a spark plug to ignite and explode, so that driving force can be obtained, and when the exhaust valve is opened, Exhaust gas after combustion is discharged from the intake port.

  FIG. 11 is a longitudinal sectional view of a tip portion of a conventional fuel injection device, and FIGS. 12 and 13 are schematic views showing a deposit state in an injection port of the conventional fuel injection device.

  In the conventional fuel injection device, as shown in FIG. 11, an injection port plate 002 is fixed to the front end portion of the housing 001, and three injection ports 003 are formed in the injection port plate 002. A needle valve 004 is movably supported in the housing 001 so that the fuel passage 005 can be opened and closed. Therefore, by moving the needle valve 004 and opening the fuel passage 005, the fuel in the fuel passage 005 can be injected from the injection port 003 into the combustion chamber 006.

  By the way, in the above-described conventional fuel injection device applied to a direct injection internal combustion engine, a predetermined amount of fuel is injected from the injection port 003 into the combustion chamber 006 by opening the fuel passage 005 for a predetermined period by the needle valve 004. However, even if the fuel injection period elapses and the fuel passage 005 is closed by the needle valve 004, a slight amount of fuel remains attached to the injection port 003. Then, as shown in FIG. 12, the fuel remaining in the injection port 003 is steamed by the high-temperature combustion gas and deposited as deposit D. Then, the deposited deposit D narrows the flow path area of the injection port 003 and becomes a flow path resistance of the fuel, causing a flow rate decrease, causing a variation in the fuel injection amount and causing deterioration of combustion.

  Therefore, as shown in FIG. 13, it is conceivable to provide a stepped portion 013 whose flow path diameter is enlarged at the tip of the injection port 012 formed in the injection port plate 011. According to this structure, the injection port 012 is moved away from the combustion chamber 014 by the stepped portion 013, so that high-temperature combustion gas does not easily flow into the fuel remaining on the injection port 012 and deposit D is deposited. Can be suppressed. In addition, there exists a thing described in the following patent document 1 as such a fuel-injection apparatus.

JP 07-310629 A

  By the way, in general, in order to prevent deposits from being deposited on the tip of the needle valve, when the fuel passage is opened by the needle valve, it adheres to the tip of the injection port due to the fluid force of the fuel flowing out of the fuel passage. It is said that it is effective to remove the deposit. However, as shown in FIG. 13, when the stepped portion 013 is provided at the tip of the injection port 012, the fuel flowing into the injection port 012 from the fuel passage is contracted and separated from the wall surface, and deposits deposited there Can not be washed away and the deposit grows. Further, when the fuel flowing into the injection port 012 contracts, the swirl component that swirls in the fuel flow direction becomes stronger, the fuel splashes, wets the wall surface of the stepped portion 013, and promotes the generation of deposits. End up.

  In addition, in the fuel injection valve of patent document 1 mentioned above, the fluid injection nozzle fixed to the exit part of the injection hole of the injection valve main body has the first orifice plate having the first orifice and the second orifice. The first orifice plate and the second orifice plate are overlapped so that the first orifice and the second orifice intersect to form a through hole in the plate thickness direction. It is a thing. However, even if the injection ports are formed so that the first orifice and the second orifice intersect, it is difficult to suppress deposit deposition.

  An object of the present invention is to solve such a problem, and an object of the present invention is to provide a fuel injection device in which combustion is improved by suppressing deposit accumulation at an injection port.

  In order to solve the above-described problems and achieve the object, a fuel injection device according to the present invention includes a housing having a fuel passage and an injection port through which the fuel passage communicates with the outside, and is movable to the housing. And an injection valve that is capable of intermittently connecting and disconnecting the fuel passage, the injection port communicating with the fuel passage and having a tapered passage diameter, and a passage diameter larger than the throttle portion in the axial direction. And an enlarged portion communicating with the outside.

  The fuel injection device according to the present invention is characterized in that a curved surface portion is provided in a communication portion between the throttle portion of the injection port and the fuel passage.

  The fuel injection device of the present invention is characterized in that an inclined surface inclined at 90 degrees or more is formed at a connection portion between the expansion portion of the injection port and the throttle portion.

  In the fuel injection device of the present invention, a linear portion that has the same diameter as the throttle portion and is constant in the axial direction is provided between the throttle portion and the enlarged portion at the injection port. It is characterized by.

  In the fuel injection device of the present invention, the first plate in which the throttle portion in the injection port is formed is fixed to the distal end portion of the housing, and the second plate in which the enlarged portion in the injection port is formed in the first plate. It is characterized by a fixed plate.

  In the fuel injection device of the present invention, a first plate having a throttle portion formed in the injection port is fixed to a front end portion of the housing, and a pipe member having an enlarged portion in the injection port is fixed to the first plate. It is characterized by that.

  In the fuel injection device of the present invention, the pipe member is provided with a covering portion that covers the periphery of the throttle portion.

  The fuel injection device according to the present invention is characterized in that the thermal conductivity of the second plate or the pipe member is set smaller than the thermal conductivity of the first plate.

  According to the fuel injection device of the present invention, the fuel passage is supported by the housing having the fuel passage and the injection port that communicates with the outside of the fuel passage at the front end portion. The injection port is configured by a throttle portion that has a tapered passage diameter and a diameter that is larger than the throttle portion and an enlarged portion that is constant in the axial direction and communicates with the outside. The fuel flow that has flowed into the fuel is accelerated at the throttle part and the flow direction component is increased, so that the separation of the fuel flow from the wall surface of the throttle part is suppressed. The fluid force of the fuel acts evenly and deposits adhering to the injection port can be removed properly, and the fuel flow direction component increases at the throttle part, so the fuel splashes generated at the enlarged part Will be reduced, It is possible to suppress the accumulation of deposits on the morphism port, as a result, to prevent the variation in the fuel injection quantity due to reduction in the fuel flow rate, it is possible to improve combustion.

  Embodiments of a fuel injection device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  1 is a cross-sectional view of a tip portion of an injector representing a fuel injection device according to Embodiment 1 of the present invention, FIG. 2 is a schematic cross-sectional view showing the shape of an injection port in the fuel injection device of Embodiment 1, and FIG. FIG. 4 is a cross-sectional view showing a main part of an internal combustion engine to which the fuel injection device of the first embodiment is applied, and FIG. 4 is a cross-sectional view showing the fuel injection device of the first embodiment.

  In the internal combustion engine to which the fuel injection device of this embodiment is applied, as shown in FIG. 3, a cylinder block 12 is assembled to the lower part of the cylinder head 11 and fastened by a plurality of fastening bolts (not shown). A plurality of cylinder bores 13 are formed in the cylinder block 12, and a piston 14 is slidably fitted to each cylinder bore 13. A crankshaft (not shown) is rotatably supported at the lower part of the cylinder block 12, and each piston 14 is connected to the crankshaft via a connecting rod 15.

  The combustion chamber 16 is constituted by a cylinder bore 13 formed in the cylinder block 12, a lower surface of the cylinder head 11, and a top surface of the piston 14, so that a central portion of the ceiling portion (lower surface of the cylinder head 11) is raised. It has a pent roof shape that is slanted. An intake port 17 and an exhaust port 18 are formed to face the upper portion of the combustion chamber 16, that is, the lower surface of the cylinder head 11, and the intake valve 19 and the exhaust valve are opposed to the intake port 17 and the exhaust port 18. 20 is located respectively. The intake valve 19 and the exhaust valve 20 are supported by the stem guides 21 and 22 fixed to the cylinder head 11 so as to be movable along the axial direction, and the intake ports 17 and the exhaust ports are supported by the valve springs 23 and 24. It is urged and supported in a direction to close 18. Further, the intake valve 19 and the exhaust valve 20 are connected to upper end portions of one end of roller rocker arms 25 and 26, and the other end portions of the roller rocker arms 25 and 26 are connected to lash adjusters 27 and 28 fixed to the cylinder head 11. The intake camshaft 29 has an intake cam 30 and the exhaust camshaft 31 has an exhaust cam 32 in contact with the roller rocker arms 25 and 26.

  Accordingly, when the intake camshaft 29 and the exhaust camshaft 31 rotate in synchronization with the internal combustion engine, the intake cam 30 and the exhaust cam 32 actuate the roller rocker arms 25 and 26, and the intake valves 19 and the exhaust valves 20 have predetermined timings. By moving up and down, the intake port 17 and the exhaust port 18 can be opened and closed, and the intake port 17 and the combustion chamber 16 and the combustion chamber 16 and the exhaust port 18 can communicate with each other.

  An injector 33 that directly injects fuel into the combustion chamber 16 is mounted on the side of the combustion chamber 16, that is, on the lower surface of the cylinder head 11 on the intake port 17 side. A spark plug 34 is attached to the center of the ceiling of the combustion chamber 16, that is, the lower surface of the cylinder head 11 between each intake port 17 and each exhaust port 18. The vehicle is equipped with an electronic control unit (ECU), which can control the fuel injection timing of the injector 33, the ignition timing by the spark plug 34, and the like. The fuel injection amount, the injection timing, the ignition timing, and the like are determined based on the engine operating state such as the throttle opening (accelerator opening) and the engine speed.

  In the above-described injector 33, as shown in FIG. 4, a valve body 42 is fixed to the tip of a hollow holder 41, and an injection port plate 43 is fixed to the tip of the valve body 42. An injection port 44 is formed in the mouth plate 43. A magnetic pipe 45 having a hollow shape is fixed to the rear end portion of the holder 41, and a cylindrical core 46 is fitted into the magnetic pipe 45, and an armature 47 is provided at the front end side of the core 46. It is supported so as to be movable in the axial direction. The magnetic pipe 45 is configured such that a non-magnetic part is positioned between magnetic parts located above and below, and the non-magnetic part prevents the magnetism from being short-circuited with the upper and lower magnetic parts. In this case, the holder 41, the valve body 42, the injection port plate 43 and the like constitute the housing of the present invention.

  The needle valve 48 as an injection valve is disposed in the holder 41 so as to be movable along the axis, and the rear end side is fitted and connected to the front end portion of the armature 47, while the front end side is in the valve body 42. It is extended. Further, the needle valve 48 has a seal portion 49 formed at the tip, while the needle valve 48 is brought to the tip side via the armature 47 between the adjustment pipe 50 and the armature 47 mounted in the core 46. An urging compression coil spring 51 is interposed, and the needle valve 48 has a seal portion 49 in contact with a valve seat portion 52 of the valve body 42.

  A coil 53 is wound around the outside of the magnetic pipe 45, a connector 54 is formed on the outside of the coil 53 by a resin mold, and a yoke 55 made of a magnetic material is fixed to the outside of the connector 54. Accordingly, when the coil 53 is energized, an electromagnetic attractive force is generated in the core 46, and the armature 47 and the needle valve 48 are moved to the rear end side (right side in FIG. 4) against the urging force of the compression coil spring 51. The seal portion 49 can be separated from the valve seat portion 52 of the valve body 42.

  Further, a fuel introduction pipe 56 is connected to the rear end portion of the magnetic pipe 45, a fuel introduction passage 57 is formed therein, and a filter 58 is attached thereto. The fuel introduction passage 57 communicates with first and second fuel passages 59 and 60 formed in the core 46 and the armature 47, and the second fuel passage 60 is connected to the first fuel passage 59 in the holder 41 through the fuel insertion hole 61. The third fuel passage 61 communicates with a fourth fuel passage 62 formed between the valve body 42 and the needle valve 48. Accordingly, when the coil 53 is not energized, the seal portion 49 of the needle valve 48 abuts against the valve seat portion 52 of the valve body 42 by the urging force of the compression coil spring 51, thereby closing the fourth fuel passage 62. ing. On the other hand, when the coil 53 is energized, the fourth fuel passage 62 is opened by separating the seal portion 49 of the needle valve 48 from the valve seat portion 52 of the valve body 42 by electromagnetic attraction force. Can be injected from the injection port 44 into the combustion chamber 16.

  In the fuel injection device of the present embodiment, the injector 33 configured as described above has three injection ports 44 (44a, 44b, 44c) formed at the tip, and the central injection port 44a is The left and right injection ports 44 b and 44 c are formed along a direction inclined by a predetermined angle with respect to the axis of the needle valve 48. Each of the injection ports 44a, 44b, and 44c has a passage diameter larger than that of the throttle portions 71a, 71b, and 71c communicating with the fourth fuel passage 62 and having a tapered passage diameter, and the throttle portions 71a, 71b, and 71c. It is composed of enlarged portions 72 a, 72 b, 72 c that are constant in the axial direction and communicate with the combustion chamber 16. That is, the throttle portions 71a, 71b, 71c have a conical shape whose base end portion communicates with the fourth fuel passage 62 and whose tip portion decreases toward the combustion chamber 16 side. On the other hand, the enlarged portions 72a, 72b, and 72c have a passage diameter larger than the distal end portions of the throttle portions 71a, 71b, and 71c and have a constant cylindrical shape in the axial direction, and the base end portions have the throttle portions 71a, 71b, and 71c. The tip is in communication with the combustion chamber 16.

  Accordingly, when the needle valve 48 is moved and the seal portion 49 is separated from the valve seat portion 52 of the valve body 42, the fourth fuel passage 62 is opened, and the fuel in the fourth fuel passage 62 is injected into each of the injection ports 44a, 44b, It is injected into the combustion chamber 16 through 44c. At this time, the fuel flow flowing into the injection ports 44a, 44b, and 44c from the fourth fuel passage 62 is accelerated by the throttle portions 71a, 71b, and 71c, and the component in the flow direction is increased. Therefore, the fuel flow passing through the throttle parts 71a, 71b, 71c is difficult to peel off from the wall surface, and the fluid force of the fuel acts uniformly on the throttle parts 71a, 71b, 71c in the circumferential direction. Deposits adhering to 44a, 44b and 44c can be removed.

  Further, as described above, after the fuel flow flowing into the injection ports 44a, 44b, 44c from the fourth fuel passage 62 is accelerated here to increase the component in the flow direction, the enlarged portions 72a, 72a, 72b, 72c flows into the enlarged portions 72a, 72b, 72c so that almost no fuel droplets are generated, and finely atomized fuel spray is injected into the combustion chamber 16, and the injection ports 44a, 44b, Deposit accumulation can be suppressed by reducing the amount of fuel adhering to 44c. In this case, the amount of fuel injected into the combustion chamber 16 is regulated at the most downstream end of the throttle portions 71a, 71b, 71c, and the passage diameter is greatly enlarged from here by the enlarged portions 72a, 72b, 72c. Therefore, even if deposits are deposited on the enlarged portions 72a, 72b, 72c, the growth on the narrowed portions 71a, 71b, 71c can be suppressed.

  As described above, in the fuel injection device according to the first embodiment, the injection plate 43 having the injection ports 44 a, 44 b, 44 c formed at the tip end portion of the valve body 42 in the injector 33 is fixed, and the valve body 42 has the inside. The needle valve 48 is movably supported, and the needle valve 48 communicates with the fourth fuel passage 62 and the injection ports 44a, 44b, 44c so that fuel can be injected into the combustion chamber 16, and communicates with the fourth fuel passage 62. The throttle portions 71a, 71b, 71c having a tapered passage diameter, and the enlarged portions 72a, 72b, 72c communicating with the combustion chamber 16 with a passage diameter larger than the throttle portions 71a, 71b, 71c and being constant in the axial direction. The nozzles 44a, 44b, and 44c are configured as described above.

  Therefore, the fuel flow flowing into the injection ports 44a, 44b, and 44c from the fourth fuel passage 62 is accelerated by the throttle portions 71a, 71b, and 71c to increase the component in the flow direction, so that the fuel flow from the wall surface is increased. Is suppressed, and the fluid force of the fuel acts uniformly on the throttle portions 71a, 71b, 71c in the circumferential direction to appropriately remove deposits adhering to the injection ports 44a, 44b, 44c. In addition, since the components in the flow direction of the fuel increase in the throttle portions 71a, 71b, 71c, fuel splashes generated in the enlarged portions 72a, 72b, 72c are reduced, and the injection ports 44a, 44b. , 44c can be suppressed, and as a result, variations in the fuel injection amount due to a decrease in the fuel flow rate can be prevented and combustion can be improved.

  FIG. 5 is a schematic cross-sectional view showing the shape of the injection port in the fuel injection device according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel injection device of the second embodiment, as shown in FIG. 5, the injection port plate 81 fixed to the tip of the injector has three injection ports 82a, 82b, and 82c. Each of the injection ports 82a, 82b, 82c communicates with the fourth fuel passage 62 and has a constricted portion 83a, 83b, 83c having a tapered passage diameter, and has a larger passage diameter than the constricted portions 83a, 83b, 83c in the axial direction. The expansion portions 84a, 84b, and 84c communicate with the combustion chamber 16 in a constant manner. Further, curved surface portions 85a, 85b, and 85c are formed at communication portions of the throttle portions 83a, 83b, and 83c of the injection ports 82a, 82b, and 82c with the fourth fuel passage 62.

  Therefore, when the needle valve moves to open the fourth fuel passage 62, the fuel in the fourth fuel passage 62 is injected into the combustion chamber 16 through the injection ports 82a, 82b, 82c. At this time, the fuel flow flowing into the injection ports 82a, 82b, and 82c from the fourth fuel passage 62 reaches the throttle portions 83a, 83b, and 83c while being guided by the curved surface portions 85a, 85b, and 85c, and the throttle portions 83a and 83b. , 83c, the flow direction component is increased. Therefore, the fuel smoothly flows into the throttle portions 83a, 83b, and 83c, and the fuel flow is hardly separated from the wall surface, and the fluid force of the fuel acts uniformly on the throttle portions 83a, 83b, and 83c in the circumferential direction. In addition, deposits adhering to the injection ports 82a, 82b, and 82c can be removed.

  Further, the fuel flow flowing from the fourth fuel passage 62 into the injection ports 82a, 82b, 82c is accelerated here to increase the component in the flow direction, and then flows into the enlarged portions 84a, 84b, 84c having a wide passage diameter. Therefore, almost no fuel splash is generated in the enlarged portions 84a, 84b, 84c, and the finely atomized fuel spray is injected into the combustion chamber 16, and the fuel adheres to the injection ports 82a, 82b, 82c. By reducing the amount, deposit accumulation can be suppressed.

  As described above, in the fuel injection device according to the second embodiment, the injection ports 82a, 82b, and 82c formed in the injection plate 81 are communicated with the fourth fuel passage 62 and the throttle portion has a tapered shape. 83a, 83b, and 83c, and enlarged portions 84a, 84b, and 84c that have larger passage diameters than the throttle portions 83a, 83b, and 83c and are constant in the axial direction and communicate with the combustion chamber 16, and the throttle portions 83a and 83b. , 83c are formed with curved surface portions 85a, 85b, 85c at communication portions with the fourth fuel passage 62.

  Therefore, the fuel in the fourth fuel passage 62 smoothly flows into the throttle portions 83a, 83b, and 83c by the curved surface portions 85a, 85b, and 85c, and is accelerated by the throttle portions 83a, 83b, and 83c to increase the component in the flow direction. As a result, the separation of the fuel flow from the wall surface is suppressed, and the fluid force of the fuel acts uniformly on the throttle portions 83a, 83b, 83c in the circumferential direction, and the injection ports 82a, 82b, 82c. The deposits adhering to the fuel can be properly removed, and the components in the fuel flow direction increase at the throttle portions 83a, 83b, 83c, so that the fuel splashes generated at the enlarged portions 84a, 84b, 84c are reduced. As a result, deposit accumulation on the injection ports 82a, 82b, and 82c can be suppressed, and as a result, variations in the fuel injection amount due to a decrease in the fuel flow rate can be prevented. And, it is possible to improve combustion.

  FIG. 6 is a schematic cross-sectional view showing the shape of an injection port in a fuel injection device according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel injection device of the third embodiment, as shown in FIG. 6, the injection port plate 91 fixed to the tip of the injector has three injection ports 92a, 92b, and 92c. Each of the injection ports 92a, 92b, and 92c communicates with the fourth fuel passage 62 and has throttle portions 93a, 93b, and 93c having a tapered passage diameter, and the passage diameter is larger than the throttle portions 93a, 93b, and 93c in the axial direction. The expansion portions 94a, 94b, and 94c communicate with the combustion chamber 16 in a constant manner. In addition, inclined surfaces 95a, 95b, and 95c having ring shapes inclined at 90 degrees or more are formed at the connecting portions of the enlarged portions 94a, 94b, and 94c of the injection ports 92a, 92b, and 92c with the throttle portions 93a, 93b, and 93c. As a result, the ceiling portions of the enlarged portions 94 a, 94 b and 94 c are separated from the combustion chamber 16.

  Accordingly, when the needle valve moves to open the fourth fuel passage 62, the fuel in the fourth fuel passage 62 is injected into the combustion chamber 16 through the injection ports 92a, 92b, 92c. At this time, the fuel flow that has flowed into the injection ports 92a, 92b, and 92c from the fourth fuel passage 62 is accelerated by the throttle portions 93a, 93b, and 93c, and the component in the flow direction is increased. Therefore, the fuel flow passing through the throttle portions 93a, 93b, and 93c is not easily separated from the wall surface, and the fluid force of the fuel acts uniformly on the throttle portions 93a, 93b, and 93c in the circumferential direction, and the injection port 92a. , 92b, 92c can be removed.

  Further, the fuel flow flowing into the injection ports 92a, 92b, 92c from the fourth fuel passage 62 is accelerated here to increase the component in the flow direction, and then flows into the enlarged portions 94a, 94b, 94c having a wide passage diameter. Therefore, almost no fuel splash is generated in the enlarged portions 94a, 94b, and 94c, and the finely atomized fuel spray is injected into the combustion chamber 16, and the fuel adheres to the injection ports 92a, 92b, and 92c. By reducing the amount, deposit accumulation can be suppressed. And since the inclined surfaces 95a, 95b, and 95c which form a ring shape are formed in the enlarged portions 94a, 94b, and 94c, the combustion gas in the combustion chamber 16 is less likely to enter the throttle portions 93a, 93b, and 93c, and the deposit Growth can be suppressed.

  As described above, in the fuel injection device of the third embodiment, the injection ports 92a, 92b, and 92c formed in the injection port plate 91 are communicated with the fourth fuel passage 62 and the throttle portion has a tapered diameter. 93a, 93b, 93c, and enlarged portions 94a, 94b, 94c having a passage diameter larger than the throttle portions 93a, 93b, 93c and being constant in the axial direction and communicating with the combustion chamber 16, and expanded portions 94a, 94b. , 94c are formed with inclined surfaces 95a, 95b, 95c inclined at 90 degrees or more at the connecting portions with the throttle portions 93a, 93b, 93c.

  Therefore, the fuel flow flowing into the injection ports 92a, 92b, and 92c from the fourth fuel passage 62 is accelerated by the throttle portions 93a, 93b, and 93c, and the component in the flow direction is increased. As a result, the fuel fluid force acts uniformly on the throttle portions 93a, 93b, 93c in the circumferential direction, and the deposits adhering to the injection ports 92a, 92b, 92c are properly removed. In addition, since the components in the flow direction of the fuel increase in the throttle portions 93a, 93b, and 93c, fuel splashes generated in the enlarged portions 94a, 94b, and 94c are reduced, and the injection ports 92a and 92b are reduced. , 92c can be prevented from depositing, and the inclined surfaces 95a, 95b, 95c cause the combustion gas in the combustion chamber 16 to flow into the throttle portions 93a, 93b, 93c. ON and hardly can suppress the growth of deposits, resulting in preventing the variation in the fuel injection quantity due to reduction in the fuel flow rate, it is possible to improve combustion.

  FIG. 7 is a schematic cross-sectional view showing the shape of the injection port in the fuel injection device according to Embodiment 4 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel injection device of the fourth embodiment, as shown in FIG. 7, three injection ports 102 a, 102 b and 102 c are formed in the injection port plate 101 fixed to the tip of the injector. Each of the injection ports 102a, 102b, 102c communicates with the fourth fuel passage 62 and has a constricted portion 103a, 103b, 103c having a tapered passage diameter, and has a larger passage diameter than the constricted portions 103a, 103b, 103c in the axial direction. From the enlarged portions 104a, 104b, 104c communicating with the combustion chamber 16 and the straight portions 105a, 105b, 105c provided between the throttle portions 103a, 103b, 103c and the enlarged portions 104a, 104b, 104c. It is configured. The straight portions 105a, 105b, and 105c have the same diameter as the downstream ends of the throttle portions 103a, 103b, and 103c, have a constant inner diameter in the axial direction, and communicate with the enlarged portions 104a, 104b, and 104c.

  Therefore, when the needle valve moves to open the fourth fuel passage 62, the fuel in the fourth fuel passage 62 is injected into the combustion chamber 16 through the injection ports 102a, 102b, 102c. At this time, the fuel flow flowing into the injection ports 102a, 102b, and 102c from the fourth fuel passage 62 is accelerated by the throttle portions 103a, 103b, and 103c, and the component in the flow direction is increased. Therefore, the fuel flow that passes through the throttle portions 103a, 103b, and 103c is difficult to peel off from the wall surface, and the fluid force of the fuel acts uniformly in the circumferential direction on the throttle portions 103a, 103b, and 103c, and the injection port 102a. , 102b, 102c can be removed.

  Further, the fuel flow that has flowed into the injection ports 102a, 102b, and 102c from the fourth fuel passage 62 is accelerated here to increase the component in the flow direction, and is rectified by the straight portions 105a, 105b, and 105c. Since the fuel flows into the enlarged portions 104a, 104b, and 104c having a wide passage diameter, almost no fuel droplets are generated in the enlarged portions 104a, 104b, and 104c, and a well atomized fuel spray is injected into the combustion chamber 16. In other words, deposit accumulation can be suppressed by reducing the amount of fuel adhering to the injection ports 102a, 102b, and 102c. Since the enlarged surfaces 104a, 104b, 104c are formed with inclined surfaces 105a, 105b, 105c having a ring shape, the combustion gas in the combustion chamber 16 is less likely to enter the throttles 103a, 103b, 103c, and the deposit Growth can be suppressed.

  As described above, in the fuel injection device of the fourth embodiment, the injection port 102a, 102b, 102c formed in the injection port plate 101 communicates with the fourth fuel passage 62 and the throttle portion has a tapered diameter. 103 a, 103 b, 103 c, expansion portions 104 a, 104 b, 104 c that have a larger passage diameter than the throttle portions 103 a, 103 b, 103 c and are constant in the axial direction and communicate with the combustion chamber 16, and the throttle portions 103 a, 103 b, 103 c It is composed of linear portions 105a, 105b, 105c having the same diameter as the downstream end portion and having a constant inner diameter in the axial direction and communicating the throttle portions 103a, 103b, 103c and the enlarged portions 104a, 104b, 104c.

  Therefore, the fuel flow flowing into the injection ports 102a, 102b, and 102c from the fourth fuel passage 62 is accelerated by the throttle portions 103a, 103b, and 103c and the component in the flow direction is increased, so that the fuel flow from the wall surface is increased. Is suppressed, and the fluid force of the fuel acts uniformly on the throttle portions 103a, 103b, and 103c in the circumferential direction, and the deposits adhering to the injection ports 102a, 102b, and 102c are appropriately removed. In addition, the components in the flow direction of the fuel increase in the throttle portions 103a, 103b, and 103c, and the rectification is performed in the straight portions 105a, 105b, and 105c, so that the fuel generated in the enlarged portions 104a, 104b, and 104c Splashes are reduced, and deposit accumulation on the injection ports 102a, 102b, 102c can be suppressed. At the same time, the inclined surfaces 105a, 105b, and 105c make it difficult for the combustion gas in the combustion chamber 16 to enter the throttle portions 103a, 103b, and 103c, thereby suppressing the growth of deposits. As a result, fuel injection due to a decrease in fuel flow rate Variations in quantity can be prevented and combustion can be improved.

  FIG. 8 is a schematic cross-sectional view showing the shape of an injection port in a fuel injection device according to Embodiment 5 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel injection device according to the fifth embodiment, as shown in FIG. 8, a first injection port plate 111 and a second injection port plate 112 are fixed to the tip of the injector. The first injection port plate 111 is formed with throttle portions 113a, 113b, and 113c communicating with the fourth fuel passage 62 and having a tapered passage diameter. Further, the passage diameter of the second injection port plate 112 is larger than that of the throttle portions 113a, 113b, 113c and is constant in the axial direction corresponding to the throttle portions 113a, 113b, 113c of the first injection plate 111. Enlarged portions 114 a, 114 b and 114 c communicating with the combustion chamber 16 are formed. In this embodiment, the throttle portions 113a, 113b, 113c and the enlarged portions 114a, 114b, 114c constitute the injection ports 115a, 115b, 115c.

  In this embodiment, the thermal conductivity of the second plate 112 that is in direct contact with the combustion gas is set smaller than the thermal conductivity of the first injection port plate 111 that is in direct contact with the fuel.

  Accordingly, when the needle valve moves to open the fourth fuel passage 62, the fuel in the fourth fuel passage 62 is injected into the combustion chamber 16 through the injection ports 115a, 115b, and 115c. At this time, the fuel flow flowing into the injection ports 115a, 115b, and 115c from the fourth fuel passage 62 is accelerated by the throttle portions 113a, 113b, and 113c, and the component in the flow direction is increased. Therefore, the fuel flow passing through the throttle portions 113a, 113b, and 113c is difficult to peel off from the wall surface, and the fluid force of the fuel acts uniformly on the throttle portions 113a, 113b, and 113c in the circumferential direction, and the injection port 115a. , 115b, 115c can be removed.

  Further, the fuel flow flowing into the injection ports 115a, 115b, and 115c from the fourth fuel passage 62 is accelerated here to increase the component in the flow direction, and then enters the enlarged portions 114a, 114b, and 114c having a wide passage diameter. Therefore, almost no fuel splash is generated in the enlarged portions 114a, 114b, and 114c, and a finely atomized fuel spray is injected into the combustion chamber 16, and the fuel to the injection ports 115a, 115b, and 115c is injected. By reducing the amount of adhesion, deposit accumulation can be suppressed.

  At this time, the second injection plate 112 that is in direct contact with the combustion gas has a higher temperature than the first injection plate 111 that is in direct contact with the fuel, but is higher than the thermal conductivity of the first injection plate 111. Since the thermal conductivity of the two jet plate 112 is set smaller, the heat of the second jet plate 112 is not easily transmitted to the first jet plate 111, and the jet port 115 a in the first jet plate 111. , 115b, 115c can be prevented from depositing due to high temperature.

  As described above, in the fuel injection device according to the fifth embodiment, the first injection plate 111 and the second injection plate 112 are fixed to the tip of the injector, and the fourth fuel passage 62 is connected to the first injection plate 111. The throttle portions 113a, 113b, and 113c having a tapered passage diameter are formed in communication with each other, while the second injection port plate 112 has a passage diameter larger than the throttle portions 113a, 113b, and 113c and is constant in the axial direction. Enlarged portions 114a, 114b, and 114c communicating with the chamber 16 are formed, and the orifices 115a, 115b, and 115c are configured by the throttle portions 113a, 113b, and 113c and the enlarged portions 114a, 114b, and 114c.

  Therefore, the fuel flow that has flowed into the injection ports 115a, 115b, and 115c from the fourth fuel passage 62 is accelerated by the throttle portions 113a, 113b, and 113c, and the component in the flow direction is increased. As a result, the fuel fluid force acts uniformly on the throttle portions 113a, 113b, 113c in the circumferential direction, and the deposits adhering to the injection ports 115a, 115b, 115c are appropriately removed. In addition, since the components in the flow direction of the fuel increase at the throttle portions 113a, 113b, and 113c, fuel splashes generated at the enlarged portions 114a, 114b, and 114c are reduced, and the injection ports 115a and 115b. , 115c, and as a result, variation in fuel injection amount due to a decrease in fuel flow rate can be reduced. Sealed, it is possible to improve combustion.

  Further, in this embodiment, the throttle portions 113a, 113b, 113c constituting the injection ports 115a, 115b, 115c are formed in the first injection plate 111, and the enlarged portions 114a, 114b, 114c are formed in the second injection plate 112. Forming. Therefore, the injection ports 115a, 115b, and 115c can be easily formed, the cost can be reduced, and the degree of freedom in manufacturing is improved, so that the injection ports can be formed according to the suitability of the fuel injection device. The shape can be optimized. And, the thermal conductivity of the second jet plate 112 is set smaller than the thermal conductivity of the first jet plate 111, the heat of the second jet plate 112 is not easily transmitted to the first jet plate 111, Deposit accumulation due to high temperatures of the injection ports 115a, 115b, and 115c can be suppressed.

  FIG. 9 is a schematic cross-sectional view showing the shape of an injection port in a fuel injection device according to Embodiment 6 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel injection device of the sixth embodiment, as shown in FIG. 9, an injection port plate 121 is fixed to the tip of the injector, and this injection port plate 121 communicates with the fourth fuel passage 62. Constrictions 122a, 122b, 122c having a tapered path diameter are formed. And pipe member 123a, 123b, 123c is being fixed corresponding to each throttle part 122a, 122b, 122c of this jet nozzle plate 121, and throttle part 122a, 122b, 122c is attached to this pipe member 123a, 123b, 123c. Enlarged portions 124 a, 124 b, and 124 c that have a larger passage diameter and are constant in the axial direction and communicate with the combustion chamber 16 are formed. In this embodiment, the orifices 125a, 125b, and 125c are constituted by the throttle portions 122a, 122b, and 122c and the enlarged portions 124a, 124b, and 124c.

  In this embodiment, the thermal conductivity of the pipe members 123a, 123b, and 123c that are in direct contact with the combustion gas is set smaller than the thermal conductivity of the injection port plate 121 that is in direct contact with the fuel.

  Accordingly, when the needle valve moves to open the fourth fuel passage 62, the fuel in the fourth fuel passage 62 is injected into the combustion chamber 16 through the injection ports 125a, 125b, 125c. At this time, the fuel flow flowing into the injection ports 125a, 125b, and 125c from the fourth fuel passage 62 is accelerated by the throttle portions 122a, 122b, and 122c, and the component in the flow direction is increased. Therefore, the fuel flow passing through the throttle portions 122a, 122b, and 122c is difficult to peel off from the wall surface, and the fluid force of the fuel acts uniformly on the throttle portions 122a, 122b, and 122c in the circumferential direction, and the injection port 125a. , 125b, 125c can be removed.

  Further, the fuel flow flowing into the injection ports 125a, 125b, and 125c from the fourth fuel passage 62 is accelerated here to increase the component in the flow direction, and then enters the enlarged portions 124a, 124b, and 124c having a wide passage diameter. Therefore, almost no fuel splash is generated in the enlarged portions 124a, 124b, and 124c, and the finely atomized fuel spray is injected into the combustion chamber 16, and the fuel to the injection ports 125a, 125b, and 125c is injected. By reducing the amount of adhesion, deposit accumulation can be suppressed.

  At this time, the pipe members 123a, 123b, and 123c that are in direct contact with the combustion gas have a high temperature with respect to the injection port plate 121 that is in direct contact with the fuel. Since the thermal conductivity of 123b and 123c is set smaller, the heat of the pipe members 123a, 123b and 123c is hardly transmitted to the injection port plate 121, and the injection ports 125a, 125b and 125c in the injection port plate 121 are not transmitted. Deposit accumulation due to high temperatures can be suppressed.

  As described above, in the fuel injection device according to the sixth embodiment, the injection port plate 121 is fixed to the tip portion of the injector, and the communication port diameter communicates with the fourth fuel passage 62 to form a tapered shape. While the throttle portions 122a, 122b, and 122c are formed, the pipe members 123a, 123b, and 123c fixed to the injection port plate 121 have a passage diameter larger than the throttle portions 122a, 122b, and 122c and are constant in the axial direction. Enlarged portions 124a, 124b, and 124c communicating with each other are formed, and the throttle portions 122a, 122b, and 122c and the enlarged portions 124a, 124b, and 124c constitute the injection ports 125a, 125b, and 125c.

  Therefore, the fuel flow that has flowed into the injection ports 125a, 125b, and 125c from the fourth fuel passage 62 is accelerated by the throttle portions 122a, 122b, and 122c, and the component in the flow direction is increased. Is suppressed, and the fluid force of the fuel acts uniformly on the throttle portions 122a, 122b, 122c in the circumferential direction, and the deposits adhering to the injection ports 125a, 125b, 125c are appropriately removed. In addition, since the components in the flow direction of the fuel increase at the throttle portions 122a, 122b, 122c, the splash of fuel generated at the enlarged portions 124a, 124b, 124c is reduced, and the injection ports 125a, 125b. , 125c, and as a result, variation in fuel injection amount due to a decrease in fuel flow rate can be reduced. Sealed, it is possible to improve combustion.

  Further, in the present embodiment, the throttle portions 122a, 122b, and 122c constituting the injection ports 125a, 125b, and 125c are formed in the injection port plate 121, and the enlarged portions 124a, 124b, and 124c are formed by the pipe members 123a, 123b, and 123c. is doing. Therefore, the injection ports 125a, 125b, and 125c can be easily formed, the cost can be reduced, and the degree of freedom in manufacturing is improved, so that the injection ports can be formed according to the suitability of the fuel injection device. The shape can be optimized. The heat conductivity of the pipe members 123a, 123b, 123c is set to be smaller than the heat conductivity of the injection port plate 121, and the heat of the pipe members 123a, 123b, 123c is not easily transmitted to the injection port plate 121, and the injection port Deposit accumulation due to high temperatures of 125a, 125b, and 125c can be suppressed.

  FIG. 10 is a schematic cross-sectional view showing the shape of an injection port in a fuel injection device according to Embodiment 7 of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in the Example mentioned above, and the overlapping description is abbreviate | omitted.

  In the fuel injection device of the seventh embodiment, as shown in FIG. 10, a first injection port plate 131 is fixed to the tip of the injector, and the first injection port plate 131 is connected to the fourth fuel passage 62. Constrictions 132a, 132b, 132c are formed which are in communication and have a tapered passage diameter. And the 2nd injection port plate 134 which has pipe part (pipe member) 133a, 133b, 133c is being fixed to this 1st injection port plate 131, and throttling part 132a, 132b is attached to this pipe part 133a, 133b, 133c. , 132c are formed with enlarged passages 135a, 135b, 135c that are larger in diameter than the passages 132c and constant in the axial direction and communicate with the combustion chamber 16. In the present embodiment, the throttle portions 132a, 132b, 132c and the enlarged portions 135a, 135b, 135c constitute the jet ports 136a, 136b, 136c, and the second jet plate 134 serves as the throttle portions 132a, 132b, 132c. It functions as a covering portion that covers the periphery.

  In this embodiment, the thermal conductivity of the second injection plate 134 that is in direct contact with the combustion gas is set smaller than the thermal conductivity of the first injection plate 131 that is in direct contact with the fuel.

  Accordingly, when the needle valve moves to open the fourth fuel passage 62, the fuel in the fourth fuel passage 62 is injected into the combustion chamber 16 through the injection ports 136a, 136b, 136c. At this time, the fuel flow flowing into the injection ports 136a, 136b, and 136c from the fourth fuel passage 62 is accelerated by the throttle portions 132a, 132b, and 132c, and the component in the flow direction is increased. Therefore, the fuel flow passing through the throttle portions 132a, 132b, and 132c is not easily separated from the wall surface, and the fluid force of the fuel acts uniformly on the throttle portions 132a, 132b, and 132c in the circumferential direction, and the injection port 136a. , 136b, 136c can be removed.

  Further, the fuel flow that has flowed into the injection ports 136a, 136b, and 136c from the fourth fuel passage 62 is accelerated here to increase the component in the flow direction, and then enters the enlarged portions 135a, 135b, and 135c having a wide passage diameter. Since the fuel flows into the expansion portions 135a, 135b, and 135c, almost no fuel splashes are generated, and the finely atomized fuel spray is injected into the combustion chamber 16, and the fuel to the injection ports 136a, 136b, and 136c is injected. By reducing the amount of adhesion, deposit accumulation can be suppressed.

  At this time, the second injection plate 134 that is in direct contact with the combustion gas has a higher temperature than the first injection plate 131 that is in direct contact with the fuel, but is higher than the thermal conductivity of the first injection plate 131. Since the thermal conductivity of the two jet plate 134 is set smaller, the heat of the second jet plate 134 is not easily transmitted to the first jet plate 131, and the jet port 136 a in the first jet plate 131. , 136b, 136c can be prevented from depositing due to high temperature.

  As described above, in the fuel injection device according to the seventh embodiment, the first injection port plate 131 is fixed to the tip of the injector, and the first injection plate 131 communicates with the fourth fuel passage 62 so that the passage diameter is increased. The narrowed portions 132a, 132b, 132c having a tapered shape are formed, while the second injection port plate 134 having pipe portions 133a, 133b, 133c is fixed to the first injection port plate 131, and the pipe portions 133a, 133b, 133c are fixed. Enlarged portions 135a, 135b, and 135c that have a passage diameter larger than that of the narrowed portions 132a, 132b, and 132c and are constant in the axial direction and communicate with the combustion chamber 16 are formed. The narrowed portions 132a, 132b, and 132c, and the enlarged portions 135a, The injection ports 136a, 136b, 136c are constituted by 135b, 135c.

  Therefore, the fuel flow flowing into the injection ports 136a, 136b, and 136c from the fourth fuel passage 62 is accelerated by the throttle portions 132a, 132b, and 132c, and the component in the flow direction is increased, so that the fuel flow from the wall surface is increased. Is suppressed, and the fluid force of the fuel acts uniformly on the throttle portions 132a, 132b, 132c in the circumferential direction, and the deposits adhering to the injection ports 136a, 136b, 136c are appropriately removed. In addition, since the components in the fuel flow direction increase at the throttle portions 132a, 132b, and 132c, fuel splashes generated at the enlarged portions 135a, 135b, and 135c are reduced, and the injection ports 136a and 136b are reduced. , 136c, and as a result, variation in fuel injection amount due to a decrease in fuel flow rate can be reduced. Sealed, it is possible to improve combustion.

  Further, in this embodiment, the narrowed portions 132a, 132b, and 132c constituting the injection ports 136a, 136b, and 136c are formed in the first injection plate 131, and the enlarged portions 135a, 135b, and 135c are formed by press working. It is formed by the injection port plate 134. Accordingly, the injection ports 136a, 136b, and 136c can be manufactured easily and inexpensively, and the cost can be reduced, and the degree of freedom in manufacturing is improved, thereby improving the suitability of the fuel injection device. Accordingly, the shape of the injection port can be optimized. And, the thermal conductivity of the second jet plate 134 is set smaller than the thermal conductivity of the first jet plate 131, the heat of the second jet plate 134 is not easily transmitted to the first jet plate 131, Deposit accumulation due to high temperatures of the injection ports 136a, 136b, and 136c can be suppressed.

  In each of the above-described embodiments, the three injection ports are provided at the tip of the injector along the direction inclined by a predetermined angle with respect to the axial center of the needle valve. However, the present invention is not limited to the embodiments described above, and may be set as appropriate depending on the shape of the combustion chamber, the shape of the combustion chamber, the mounting position of the injector, and the like.

  In each of the above-described embodiments, the cylinder injection type internal combustion engine that injects fuel directly into the combustion chamber has been described. However, the same effect as described above can be applied to a port injection type internal combustion engine that injects fuel into the intake port. There is an effect.

  As described above, the fuel injection device according to the present invention is intended to improve combustion by suppressing the accumulation of deposits at the injection port by providing the throttle portion and the enlarged portion at the injection port. This type of internal combustion engine is also suitable.

It is sectional drawing of the front-end | tip part of the injector showing the fuel-injection apparatus which concerns on Example 1 of this invention. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus of Example 1. FIG. It is principal part sectional drawing of the internal combustion engine to which the fuel-injection apparatus of Example 1 was applied. 1 is a cross-sectional view illustrating a fuel injection device according to a first embodiment. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus which concerns on Example 2 of this invention. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus which concerns on Example 3 of this invention. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus which concerns on Example 4 of this invention. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus which concerns on Example 5 of this invention. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus which concerns on Example 6 of this invention. It is a schematic sectional drawing showing the shape of the injection port in the fuel-injection apparatus which concerns on Example 7 of this invention. It is a longitudinal cross-sectional view of the front-end | tip part of the conventional fuel injection apparatus. It is the schematic showing the deposit state of the deposit in the injection port of the conventional fuel injection apparatus. It is the schematic showing the deposit state of the deposit in the injection port of the conventional fuel injection apparatus.

Explanation of symbols

16 Combustion chamber 33 Injector 34 Spark plug 41 Holder (housing)
42 Valve body (housing)
43, 81, 91, 101, 111, 112, 121 Injection port plate (housing)
44, 44a, 44b, 44c, 82a, 82b, 82c, 92a, 92b, 92c, 102a, 102b, 102c, 115a, 115b, 115c, 125a, 125b, 125c Injection port 48 Needle valve 49 Seal unit 52 Valve seat unit 62 Fourth fuel passages 71a, 71b, 71c, 83a, 83b, 83c, 93a, 93b, 93c, 103a, 103b, 103c, 113a, 113b, 113c, 122a, 122b, 122c throttle parts 72a, 72b, 72c, 84a, 84b , 84c, 94a, 94b, 94c, 104a, 104b, 104c, 114a, 114b, 114c, 124a, 124b, 124c Enlarged part 85a, 85b, 85c Curved part 95a, 95b, 95c Inclined surface 105a, 105b, 105c Linear part 123 , 123b, 123c pipe member

Claims (8)

  A housing having a fuel passage and an injection port that communicates with the fuel passage to the outside at a tip portion; and an injection valve that is movably supported by the housing and can interrupt the fuel passage. A fuel injection device comprising: a throttle portion communicating with the fuel passage and having a tapered passage diameter; and an enlarged portion having a passage diameter larger than the throttle portion and constant in the axial direction and communicating with the outside. .   2. The fuel injection device according to claim 1, wherein a curved portion is provided in a communication portion between the throttle portion of the injection port and the fuel passage. 3.   2. The fuel injection device according to claim 1, wherein an inclined surface inclined at 90 degrees or more is formed in a connection portion between the expansion portion of the injection port and the throttle portion.   2. The fuel injection device according to claim 1, wherein a linear portion that has the same diameter as the throttle portion and is constant in the axial direction is provided between the throttle portion and the enlarged portion at the injection port. A fuel injection device characterized in that the fuel injection device is provided.   The fuel injection device according to claim 1, wherein a first plate in which a throttle portion in the injection port is formed is fixed to a distal end portion of the housing, and an enlarged portion in the injection port is formed in the first plate. A fuel injection device characterized in that the second plate is fixed.   2. The fuel injection device according to claim 1, wherein a first plate in which a throttle portion in the injection port is formed is fixed to a distal end portion of the housing, and a pipe having an enlarged portion in the injection port in the first plate. A fuel injection device characterized in that a member is fixed.   The fuel injection device according to claim 6, wherein the pipe member is provided with a covering portion that covers the periphery of the throttle portion.   7. The fuel injection device according to claim 5, wherein a thermal conductivity of the second plate or the pipe member is set smaller than a thermal conductivity of the first plate.

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