Fuel injection device and reciprocating internal combustion engine

Abstract

To improve ignitability of fuel in a fuel injection device and a reciprocating internal combustion engine.SOLUTION: A fuel injection device includes: a first fuel supply passage for supplying first fuel with predetermined ignitability; a second fuel supply passage for supplying second fuel with ignitability lower than that of the first fuel; and a fuel injection valve to which the first fuel supply passage and the second fuel supply passage are connected. The fuel injection valve includes: a body having a tip part with a nozzle hole; a first needle valve movably provided within the body; and a second needle valve movably provided between the body and the first needle valve. The body, the first needle valve and the second needle valve are disposed concentrically. When the first needle valve moves to separate from the second needle valve, the first fuel supply passage communicates with the nozzle hole to inject the first fuel, and when the second needle valve moves to separate from the body, the second fuel supply passage communicates with the nozzle hole to inject the second fuel.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a fuel injection device and a reciprocating internal combustion engine.

Background Art

[0002] A reciprocating internal combustion engine is equipped with a fuel injection device. The reciprocating internal combustion engine burns by injecting fuel into the high-pressure air in the combustion chamber by the fuel injection device, and is driven by the generated combustion energy. In recent years, as a fuel applied to the fuel injection device, it has been considered to use a carbon-free fuel with a small amount of generation of harmful substances (for example, carbon dioxide, etc.). However, some carbon-free fuels have poor ignitability and combustibility, and it has been proposed to use them in combination with fuels having good ignitability and combustibility. As a fuel injection device that injects a plurality of types of fuels, for example, there is one described in Patent Document 1 below.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A conventional fuel injection device injects a fuel with poor ignitability and a fuel with good ignitability. At this time, it is necessary to serve as an ignition source for the fuel with good ignitability to ignite the fuel with poor ignitability, and an improvement in the ignitability of the fuel is desired.

[0005] The present disclosure solves the above-described problems, and an object thereof is to provide a fuel injection device and a reciprocating internal combustion engine that improve the ignitability of fuel.

Means for Solving the Problems

[0006] To achieve the above object, the fuel injection device of the present disclosure includes a first fuel supply path for supplying a first fuel having a predetermined ignitability, a second fuel supply path for supplying a second fuel having a lower ignitability than the first fuel, and a fuel injection valve to which the first fuel supply path and the second fuel supply path are connected. The fuel injection valve includes a main body provided with a nozzle at its tip, a first needle valve movably provided inside the main body and allowing the first fuel supply path to communicate with the nozzle according to the moving position, and a second needle valve movably provided between the main body and the first needle valve and allowing the second fuel supply path to communicate with the nozzle according to the moving position. The main body, the first needle valve, and the second needle valve are concentric. When the first needle valve moves away from the second needle valve, the first fuel supply path communicates with the nozzle to inject the first fuel. When the second needle valve moves away from the main body, the second fuel supply path communicates with the nozzle to inject the second fuel.

[0007] Further, the reciprocating internal combustion engine of the present disclosure includes an internal combustion engine main body having a combustion chamber and the fuel injection device according to claim 1 for injecting fuel into the combustion chamber.

Advantages of the Invention

[0008] According to the fuel injection device and the reciprocating internal combustion engine of the present disclosure, the ignitability of the fuel can be improved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited by this embodiment, and when there are a plurality of embodiments, those configured by combining each embodiment are also included. In addition, the constituent elements in the embodiment include those that can be easily assumed by those skilled in the art, substantially the same ones, and those within a so-called equivalent range.

[0011] [First Embodiment] <Engine> FIG. 1 is a schematic diagram showing an engine of the first embodiment. In the first embodiment, the engine is a reciprocating internal combustion engine.

[0012] As shown in FIG. 1, the engine 10 includes an engine body 11, an intake passage 12, an exhaust passage 13, and a fuel injection device 14.

[0013] The engine body 11 is a multi-cylinder engine. The engine body 11 has a plurality (six in this embodiment) of combustion chambers 21. An intake passage 12 is connected to each intake port 22 of each combustion chamber 21, and an exhaust passage 13 is connected to each exhaust port 23 of each combustion chamber 21. The intake passage 12 supplies the air inhaled from the outside from each intake port 22 to each combustion chamber 21. The exhaust passage 13 discharges the combustion gas burned in each combustion chamber 21, that is, the exhaust gas, from each exhaust port 23 to the outside.

[0014] The combustion chamber 21 is a space portion having a cylindrical shape, and a piston (not shown) is movably supported therein. Although not shown, the engine body 11 has a crankshaft rotatably supported at the lower part, and the piston and the crankshaft are connected via a connecting rod. The combustion chamber 21 is a space partitioned by the engine body 11 and the piston. The intake port 22 can be opened and closed by an intake valve, and the exhaust port 23 can be opened and closed by an exhaust valve.

[0015] The fuel injection device 14 includes a fuel supply device 31, a fuel supply passage 32, and a fuel injection valve 33. The fuel injection valve 33 is attached to the engine body 11. The fuel injection valve 33 can inject fuel into the combustion chamber 21. The fuel injection valve 33 is connected to the fuel supply device 31 via the fuel supply passage 32. The fuel supply device 31 can supply the fuel stored in a fuel tank (not shown) to the fuel injection valve 33 through the fuel supply passage 32.

[0016] When air is supplied from the intake passage 12 to the combustion chamber 21 in the engine 10, the air is compressed by the upward movement of the piston. Further, the fuel supply device 31 supplies fuel to the fuel injection valve 33 through the fuel supply passage 32, and the fuel injection valve 33 supplies fuel to the combustion chamber 21. In the combustion chamber 21, the fuel is ignited and the fuel and air burn to operate the piston. The combustion gas generated in the combustion chamber 21 is discharged as exhaust gas to the exhaust passage 13.

[0017] <Configuration of Fuel Injection Device> FIG. 2 is a schematic configuration diagram showing the fuel injection device of the first embodiment.

[0018] As shown in FIG. 2, the fuel injection device 14 includes a fuel supply device 31, a fuel supply passage 32, and a fuel injection valve 33. The fuel supply device 31 has a first fuel supply device 41 and a second fuel supply device 42. The fuel supply passage 32 has a first fuel supply passage 43 and a second fuel supply passage 44. The fuel injection valve 33 has a first needle valve 45 and a second needle valve 46. Further, the fuel injection device 14 includes a spool valve mechanism 47 and a piston mechanism 48.

[0019] The fuel injection device 14 can inject a first fuel having a predetermined ignitability and can also inject a second fuel having lower (worse) ignitability than the first fuel. Here, the ignitability refers to the ease of ignition of the first fuel and the second fuel. The first fuel is a fossil fuel (for example, light oil or heavy oil as fuel), and the second fuel is, for example, ammonia, methanol, liquefied petroleum gas (LPG), etc. However, the first fuel and the second fuel are not limited to the fuels described above.

[0020] In the first embodiment, a common rail system is applied. The common rail system stores fuel pressurized by a fuel pump in a common rail (accumulator chamber) and injects it from the fuel injection valve into the combustion chamber by electronic control. By storing high-pressure fuel in the common rail, not only can the fuel be super-pressurized, but also the injection pressure, injection amount, injection timing, etc. can be controlled without depending on the engine rotation speed.

[0021] The first fuel supply device 41 has a common rail. The first fuel supply device 41 pressurizes the first fuel in the common rail to a predetermined pressure (for example, 150 MPa) and supplies it to the first fuel supply passage 43. The second fuel supply device 42 pressurizes the second fuel to a predetermined pressure (for example, 10 MPa) and supplies it to the second fuel supply passage 44.

[0022] The fuel injection valve 33 has a first needle valve 45 and a second needle valve 46 supported movably in the longitudinal direction with respect to the main body 51. In FIG. 2, the intermediate portion of the main body 51 is omitted. The main body 51 is provided with a first nozzle 52 and a second nozzle 53 at positions having different radial directions at the tip end portion (the lower end portion in FIG. 2). A plurality of first nozzles 52 are provided at intervals in the circumferential direction on the tip end portion side of the main body 51. A plurality of second nozzles 53 are provided at intervals in the circumferential direction on the base end portion side (the upper end portion in FIG. 2) of the main body 51 with respect to the first nozzle 52. The plurality of first nozzles 52 communicate with the first chamber 54, and the second nozzle 53 communicates with the second chamber 55. Further, the main body 51 is provided with a third chamber 56 on the upper end portion side with respect to the second chamber 55. Each of the chambers 54, 55, 56 has a ring shape along the circumferential direction.

[0023] The first needle valve 45 has a cylindrical shape and includes a valve body 61, a flange portion 62, a biasing spring (biasing member) 63, and a first fuel flow path 64. The second needle valve 46 has a cylindrical shape and includes a valve body 65 and a second fuel flow path 66. The second needle valve 46 is disposed inside the main body 51, and the first needle valve 45 is disposed inside the second needle valve 46. The first needle valve 45 and the second needle valve 46 are supported movably relative to the main body 51. The biasing force of the biasing spring 63 acts on the valve body 61 of the first needle valve 45 via the flange portion 62. The first needle valve 45 is biased downward and is biased and supported by the main body 51 via the second needle valve 46. Therefore, the outer surface of the tip end portion of the first needle valve 45 is in close contact with the inner surface of the tip end portion of the second needle valve 46, and the outer surface of the tip end portion of the second needle valve 46 is in close contact with the inner surface of the main body 51. At this time, the communication between the first fuel flow path 64 of the first needle valve 45 and the second fuel flow path 66 of the second needle valve 46 is blocked by the first seat portion S1. Further, the communication between the second chamber 55 and the third chamber 56 of the main body 51 is blocked by the second seat portion S2. Furthermore, the communication between the second chamber 55 of the main body 51 and the second fuel flow path 66 of the first chamber 54 is blocked by the third seat portion S3.

[0024] The first fuel supply path 43 branches at its downstream end into two branch paths 71 and 72. The first branch path 71 has its downstream end communicating with the control chamber 67 of the fuel injection valve 33. The control chamber 67 is partitioned between the base end of the main body 51 and the base end of the first needle valve 45. The second branch path 72 communicates with the first fuel flow path 64 of the first needle valve 45. The second fuel supply path 44 branches at its downstream end into two branch paths 73 and 74. The first branch path 73 has its downstream end communicating with the piston mechanism 48. The second branch path 74 communicates with the third chamber 56 of the main body 51. A check valve 68 is provided upstream of the branch paths 73 and 74 in the second fuel supply path 44. The check valve 68 prevents the backflow of the second fuel from the piston mechanism 48 side and the fuel injection valve 33 side to the second fuel supply device 42 side. Note that the opening pressure of the check valve 68 from the second fuel supply device 42 side to the piston mechanism 48 and the fuel injection valve 33 side is set. Further, a drain path 75 communicates with the base end of the main body 51 of the fuel injection valve 33, and an electromagnetic valve (on-off valve) 69 is provided in the drain path 75. Furthermore, a throttle 70 is provided in the first branch path 71 of the first fuel supply path 43.

[0025] The fuel injection valve 33 is configured such that the first needle valve 45 is in close contact with the second needle valve 46 due to the biasing force of the biasing spring 63, and the second needle valve 46 is in close contact with the main body 51. In this state, the first fuel at a predetermined pressure is supplied from the first fuel supply device 41 to the control chamber 67 via the first branch passage 71 from the first fuel supply passage 43, and is also supplied to the first fuel passage 64 of the first needle valve 45 via the second branch passage 72. When the solenoid valve 69 is in the closed state, the first needle valve 45 is in the lowered position biased downward by the biasing force of the biasing spring 63 and the supply pressure of the first fuel to the control chamber 67. Therefore, the communication between the first fuel passage 64 of the first needle valve 45 and the second fuel passage 66 of the second needle valve 46 is blocked by the first seat portion S1, and the injection of the first fuel from the first nozzle 52 is stopped. Also, similarly, the second needle valve 46 is in the lowered position biased downward via the first needle valve 45 by the biasing force of the biasing spring 63 and the supply pressure of the first fuel to the control chamber 67. Therefore, the communication between the second chamber 55 and the third chamber 56 of the main body 51 is blocked by the second seat portion S2, and the communication between the second chamber 55 of the main body 51 and the second fuel passage 66 of the first chamber 54 is blocked by the third seat portion S3, and the injection of the second fuel from the first nozzle 52 and the second nozzle 53 is stopped.

[0026] The spool valve mechanism 47 has a spool valve 80. The spool valve 80 has a casing 81 and a valve body 82. The casing 81 has a hollow cylindrical shape, and the valve body 82 has a string shape in which two spools 82a and 82b having a cylindrical shape are connected by a connecting portion 82c. The spool valve 80 is provided with a supply port 83 and a discharge port 84 on one side (the left side in FIG. 2) of the casing 81, and a supply / discharge port 85 on the other side (the right side in FIG. 2). The spool valve 80 is configured such that when the valve body 82 is located on one side (the lower side in FIG. 2), the discharge port 84 and the supply / discharge port 85 communicate with each other. The spool valve 80 is configured such that when the valve body 82 is located on the other side (the upper side in FIG. 2), the supply port 83 and the supply / discharge port 85 communicate with each other.

[0027] The first fuel supply device 41 is connected to a first fuel supply path 86, and the downstream side of the first fuel supply path 86 branches into three communication paths 86a, 86b, and 86c. The spool valve 80 has the downstream end of the second communication path 86b communicating with the spool 82a side of the valve body 82, and the downstream end of the first communication path 86a communicating with the spool 82b side of the valve body 82. The second communication path 86b is provided with a throttle 87. Also, the spool valve 80 has a drain path 88 communicating with the spool 82a side of the valve body 82, and the drain path 88 is provided with an electromagnetic valve (on-off valve) 89. Note that the first fuel supply path 86 supplies the first fuel at a predetermined pressure, similar to the first fuel supply path 43.

[0028] The spool valve mechanism 47 has a third communication path 86c connected to the supply port 83. Also, the spool valve mechanism 47 has a return path 91 connected to the discharge port 84. The return path 91 is connected to a return path 94 via a check valve 92. The check valve 92 prevents the backflow of the first fuel to the spool valve 80 side. Note that the opening pressure of the first fuel is set for the check valve 92. Further, the spool valve mechanism 47 has a communication path 93 connected to the supply and discharge port 85 and communicating with the piston mechanism 48.

[0029] The piston mechanism 48 is provided between the first fuel supply path 86 and the second fuel supply path 44. The piston mechanism 48 has a cylinder 101 having a cylindrical shape and a piston 102 having a cylindrical shape. The piston 102 is disposed inside the cylinder 101 and is supported so as to be movable along the axial direction. One end portion of the cylinder 101 in the moving direction of the piston 102 communicates with the communication path 93 from the spool valve mechanism 47, and the other end portion of the cylinder 101 in the moving direction of the piston 102 communicates with the first branch path 73 of the second fuel supply path 44.

[0030] The piston 102 has a first pressure receiving surface 102a formed on the communicating passage 93 side and a second pressure receiving surface 102b formed on the first branch passage 73 side. The first fuel supply pressure from the communicating passage 93 acts on the first pressure receiving surface 102a of the piston 102, and the second fuel supply pressure from the first branch passage 73 acts on the second pressure receiving surface 102b of the piston 102. The piston mechanism 48 reciprocates the piston 102 by the differential pressure between the first fuel supply pressure and the second fuel supply pressure.

[0031] The piston mechanism 48 is provided with a first storage portion 103 that communicates with the communicating passage 93 on the first pressure receiving surface 102a side and stores the first fuel, and a second storage portion 104 that communicates with the first branch passage 73 on the second pressure receiving surface 102b side and stores the second fuel. The piston 102 has a rod portion 102c. The piston 102 has a smaller area of the first pressure receiving surface 102a than that of the second pressure receiving surface 102b due to the rod portion 102c.

[0032] Therefore, when the solenoid valve 89 is in the closed state, the second fuel in the second fuel supply passage 44 is supplied to the second storage portion 104 of the piston mechanism 48 through the check valve 68. Here, the pressure in the first storage portion 103 is higher than the pressure in the second storage portion 104 due to the area difference between the first pressure receiving surface 102a and the second pressure receiving surface 1022b of the piston mechanism 48. The spool valve mechanism 47 has the discharge port 84 and the supply / discharge port 85 communicating with each other, and the check valve 92 is opened by the pressure of the first fuel in the first storage portion 103, and the first fuel is discharged to the return passage 91. Then, the piston mechanism 48 moves the piston 102 to the communicating passage 93 side, and a predetermined amount of the second fuel is stored in the second storage portion 104.

[0033] On the one hand, when the solenoid valve 89 is in the open state, in the spool valve mechanism 47, the first fuel supplied to the spool 82a side is discharged from the drain path 88, and the valve body 82 of the spool valve 80 moves to the drain path 88 side. At this time, in the spool valve mechanism 47, the supply port 83 and the supply / discharge port 85 communicate with each other, and the first fuel is supplied to the first storage portion 103 of the piston mechanism 48 via the communication path 93, and the pressure in the first storage portion 103 becomes higher than the pressure in the second storage portion 104. Then, in the piston mechanism 48, the piston 102 moves to the first branch path 73 side, and the second fuel in the second storage portion 104 is supplied to the second needle valve 46 of the fuel injection valve 33 through the branch paths 73 and 74.

[0034] At this time, due to the area ratio of the piston 102, the pressure in the first storage portion 103 is kept higher than that in the second storage portion 104, and a small amount of the first fuel in the first storage portion 103 penetrates into the sliding portion between the cylinder 101 and the piston 102. Therefore, the piston mechanism 48 can improve the lubricity of the sliding surface between the cylinder 101 and the piston 102, and can prevent the second fuel in the second storage portion 104 from penetrating into the first storage portion 103 side and mixing into the first fuel.

[0035] The control device 105 is connected to the solenoid valves 69 and 89. The control device 105 adjusts the injection timing and injection amount of the first fuel and the second fuel from the fuel injection valve 33 by controlling the opening and closing timing of the solenoid valves 69 and 89.

[0036] <Fuel path of the fuel injection device> Figure 3 is a schematic configuration diagram showing the fuel path of the fuel injection device.

[0037] As shown in FIG. 3, the engine 10 has an engine body 11, and the engine body 11 has a plurality (six in this embodiment) of combustion chambers 21. The engine body 11 has a fuel injection device 14, and the fuel injection device 14 has a fuel supply device 31, a fuel supply path 32, and a fuel injection valve 33. A plurality of fuel injection valves 33 are provided corresponding to each combustion chamber 21, and each fuel injection valve 33 can inject fuel into each combustion chamber 21. In the following description, the fuel supply device 31 and the fuel supply path 32 for one fuel injection valve 33 will be described, and the others will be omitted.

[0038] The fuel supply device 31 has a first fuel supply device 41 and a second fuel supply device 42. The fuel supply path 32 has a first fuel supply path 43 and a second fuel supply path 44. The first fuel supply device 41 has a common rail 41A and high-pressure pumps 41B, 41C. The high-pressure pumps 41B, 41C are connected to a supply path 112 from a fuel tank 111 of the first fuel. The high-pressure pump 41B can be driven by a drive motor 113 via a gear to a crankshaft (not shown), and the high-pressure pump 41C can be driven by the drive motor 113. The high-pressure pump 41B is connected to a drain path 75 and a drain path 88 from the fuel injection valve 33. The common rail 41A is connected to the high-pressure pumps 41B, 41C and is also connected to the fuel injection valve 33.

[0039] Further, a pressure accumulator tank 114 is connected to a return path 94 from a spool valve mechanism 47, a supply path 115 of the first fuel from the fuel tank 111 is connected, and a boost pump 116 is mounted on the supply path 115. Also, the pressure accumulator tank 114 is provided with a return path 117 to the fuel tank 111, and a pressure regulating valve 118 is provided on the return path 117.

[0040] The second fuel supply device 42 is connected to the common rail 42B by the second fuel supply path 44. The common rail 42B is connected to the fuel injection valve 33 and is also connected to the piston mechanism 48. Further, the second fuel supply path 44 is provided with a switching valve 122, and a purge gas supply source 124 is connected to the switching valve 122 via a supply path 123. Here, the purge gas is, for example, nitrogen. And a recovery path 125 of the second fuel purged by the purge gas is connected to the second fuel supply device 42 from the piston mechanism 48.

[0041] <Fuel injection valve> FIG. 4 is a cross-sectional view showing the main part of the fuel injection valve, and FIG. 5 is a schematic view showing the fuel injection pattern by the fuel injection valve.

[0042] As shown in FIGS. 4 and, the fuel injection valve 33 has a main body 51, a first needle valve 45, and a second needle valve 46. The main body 51, the first needle valve 45, and the second needle valve 46 are arranged concentrically about an axis O1. The main body 51 is provided with a first chamber 54, a second chamber 55, and a third chamber 56 at its tip. A first nozzle 52 is formed in the first chamber 54, a second nozzle 53 is formed in the second chamber 55, and a second branch path 74 of the second fuel supply path 44 is connected to the third chamber 56. A plurality of first nozzles 52 are provided at intervals in the circumferential direction of the first chamber 54. A plurality of second nozzles 53 are provided at intervals in the circumferential direction of the second chamber 55. The positions of the first nozzle 52 and the second nozzle 53 are shifted from each other in the circumferential direction.

[0043] The first needle valve 45 has a first fuel flow path 64 provided at the central portion of the valve body 61. The second needle valve 46 has a second fuel flow path 66 provided at the tip of the valve body 65. The main body 51 has the second needle valve 46 disposed therein, and the first needle valve 45 disposed inside the second needle valve 46. A first sheet portion S1 is provided between the first fuel flow path 64 of the first needle valve 45 and the second fuel flow path 66 of the second needle valve 46. In this case, the valve body 65 is provided with a storage portion 65a having a ring shape and facing the outlet portion of the first fuel flow path 64 between the valve body 65 and the valve body 61. Further, the valve body 65 is provided with an inclined surface 65b such that the gap between the valve body 65 and the valve body 61 increases from the storage portion 65a toward the second fuel flow path 66. The first sheet portion S1 is provided in a ring shape between the storage portion 65a and the inclined surface 65b.

[0044] Also, a second sheet portion S2 is provided between the second chamber 55 and the third chamber 56 of the main body 51. Further, a third sheet portion S3 is provided between the second chamber 55 of the main body 51 and the second fuel flow path 66 of the first chamber 54. In this case, the valve body 65 is provided with an inclined surface 65c such that the gap between the valve body 65 and the main body 51 decreases from the third chamber 56 toward the second chamber 55 between the valve body 65 and the main body 51. Also, the valve body 65 is provided with an inclined surface 65d such that the gap between the valve body 65 and the main body 51 increases from the second chamber 55 toward the second fuel flow path 66 between the valve body 65 and the main body 51. The second sheet portion S2 is provided in a ring shape between the inclined surface 65c and the second chamber 55, and the third sheet portion S3 is provided in a ring shape between the second chamber 55 and the inclined surface 65d.

[0045] Therefore, when the first needle valve 45 rises with respect to the second needle valve 46, the fuel injection valve 33 has its first seat portion S1 opened, and the first fuel in the first fuel passage 64 of the first needle valve 45 flows into the second fuel passage 66 of the second needle valve 46 and is supplied to the first chamber 54. Then, the plurality of first nozzles 52 inject the first fuel radially. When the second needle valve 46 rises with respect to the main body 51, the second seat portion S2 and the third seat portion S3 are opened, and the second fuel in the third chamber 56 is supplied to the second chamber 55 and the first chamber 54. Then, the plurality of first nozzles 52 and the plurality of second nozzles 53 inject the second fuel radially. At this time, the first seat portion S1 is closed, the flow of the first fuel from the first fuel passage 64 of the first needle valve 45 to the second fuel passage 66 of the second needle valve 46 is blocked, and the injection of the first fuel from the plurality of first nozzles 52 stops.

[0046] <Operation of the fuel injection device> FIG. 6 is a schematic configuration diagram showing the second fuel filling state by the fuel injection device, FIG. 7 is a schematic configuration diagram showing the first fuel injection state by the fuel injection device, and FIG. 8 is a schematic configuration diagram showing the second fuel injection state by the fuel injection device.

[0047] As shown in FIG. 6, when the solenoid valve 69 is closed (non-energized), the fuel injection valve 33, as described above, has the first needle valve 45 lowered, and the communication between the first fuel passage 64 and the second fuel passage 66 is blocked by the first seat portion S1, and the first fuel is not injected from the first nozzle 52. Similarly, the second needle valve 46 also has the communication between the third chamber 56, the second chamber 55, and the second fuel passage 66 blocked by the second seat portion S2 and the third seat portion S3, and the second fuel is not injected from the first nozzle 52 and the second nozzle 53.

[0048] At this time, when the solenoid valve 89 is in the closed (non-energized) state, the check valve 68 is opened by the pressure difference between the pressure of the second fuel in the second fuel supply path 44 and the pressure of the return path 94, and the second fuel is filled into the second storage portion 104 of the piston mechanism 48 through the first branch path 73. The piston mechanism 48 has a higher pressure in the first storage portion 103 than in the second storage portion 104 due to the area difference between the first pressure receiving surface 102a and the second pressure receiving surface 102b. The spool valve mechanism 47 has the discharge port 84 and the supply / discharge port 85 communicating with each other, and the check valve 92 is opened by the pressure of the first fuel in the first storage portion 103, and the first fuel is discharged into the return path 91. Then, the piston mechanism 48 moves the piston 102 upward on the communicating path 93 side, and a predetermined amount of the second fuel can be stored in the second storage portion 104.

[0049] For example, the pressure of the second fuel in the second fuel supply path 44 is set to 10 MPa, the pressure of the first fuel in the return path 94 is set to 11 MPa, and the area ratio of the first pressure receiving surface 102a and the second pressure receiving surface 102b on the piston 102 is set to 1.2. At this time, the pressure of the second fuel in the second storage portion 104, which is 10 MPa, increases the pressure of the first fuel in the first storage portion 103 by the piston 102 to 12 MPa, which is higher than the pressure of the first fuel in the return path 94, opening the check valve 92, and the piston 102 can rise to the top dead center.

[0050] As shown in FIG. 7, when the solenoid valve 69 is opened (energized), in the fuel injection valve 33, the first fuel in the control chamber 67 is discharged from the drain path 75, and the first needle valve 45 moves upward by the supply pressure of the first fuel to the first fuel flow path 64. Then, the first seat portion S1 is opened, the first fuel in the first fuel flow path 64 is supplied to the first chamber 54 through the second fuel flow path 66, and the first fuel is injected from the first nozzle 52.

[0051] At this time, as shown in FIG. 8, when the solenoid valve 89 is opened (energized), in the spool valve mechanism 47, the first fuel on the spool 82a side is discharged from the drain path 88, and the valve body 82 moves toward the drain path 88 side. Then, in the spool valve mechanism 47, the supply port 83 and the supply / discharge port 85 communicate with each other, and the first fuel in the first fuel supply path 86 flows through the spool valve 80 into the communication path 93 and is supplied to the first storage portion 103 of the piston mechanism 48. When the first fuel is supplied to the first storage portion 103 of the piston mechanism 48, the pressure in the first storage portion 103 becomes higher than the pressure in the second storage portion 104, and the piston 102 moves toward the first branch path 73 side. Then, the piston mechanism 48 supplies the second fuel in the second storage portion 104 to the first branch path 73 and the second branch passage 74.

[0052] When the piston 102 of the piston mechanism 48 descends and the second fuel in the second storage portion 104 is supplied to the first branch path 73, the pressure of the second fuel in the first branch path 73 and the second branch passage 74 increases. Then, when the second fuel is supplied from the second branch passage 74 to the third chamber 56 in the fuel injection valve 33, the second needle valve 46 moves upward by the supply pressure of the second fuel. Then, the third chamber 56 communicates with the second chamber 55, the second fuel in the third chamber 56 is supplied to the second chamber 55, and the second fuel in the second chamber 55 is supplied to the first chamber 54. At this time, in the fuel injection valve 33, when the second needle valve 46 rises and comes into close contact with the first needle valve 45, the communication between the fuel flow paths 64 and 66 is blocked by the first seat portion S1, and the injection of the first fuel from the first nozzle 52 stops. On the other hand, when fuel is supplied to the first chamber 54 and the second chamber 55, the second fuel is injected from the first nozzle 52 and the second nozzle 53.

[0053] <Fuel injection timing> FIG. 9 is a time chart showing the operation of the injection timing of the first fuel and the second fuel by the fuel injection device.

[0054] As shown in FIGS. 2 and 9, in FIG. 9(a), the solenoid valve 69 as the first fuel solenoid valve is opened, and then the solenoid valve 89 as the second fuel solenoid valve is opened with a delay. Then, first, the first needle valve 45 rises and the first fuel is injected, and then the second needle valve 46 rises and the second fuel is injected. After that, the solenoid valve 89 as the second fuel solenoid valve is closed, and then the solenoid valve 69 as the first fuel solenoid valve is closed with a delay. Then, first, the second needle valve 46 descends and the injection of the second fuel stops, and then the first needle valve 45 descends and the injection of the first fuel stops. Alternatively, the solenoid valve 69 as the first fuel solenoid valve may be once closed during the period when the solenoid valve 89 as the second fuel solenoid valve is open, and then reopened simultaneously with the closing of the solenoid valve 89.

[0055] In FIG. 9(b), the solenoid valve 69 as the first fuel solenoid valve is opened, and then the solenoid valve 89 as the second fuel solenoid valve is opened with a delay. Then, first, the first needle valve 45 rises and the first fuel is injected, and then the second needle valve 46 rises and the injection of the first fuel stops and the second fuel is injected. After that, the solenoid valve 69 as the first fuel solenoid valve and the solenoid valve 89 as the second fuel solenoid valve are closed simultaneously. Then, the first needle valve 45 and the second needle valve 46 descend simultaneously, and the injection of the second fuel stops.

[0056] In FIG. 9(c), the solenoid valve 69 as the first fuel solenoid valve is opened, and the solenoid valve 89 as the second fuel solenoid valve is closed. Then, the first needle valve 45 rises and the first fuel is injected, and the second fuel is not injected. After that, the solenoid valve 69 as the first fuel solenoid valve is closed. Then, the first needle valve 45 descends and the injection of the first fuel stops.

[0057] In FIG. 9(d), the solenoid valve 69 as the first fuel solenoid valve is closed, and the solenoid valve 89 as the second fuel solenoid valve is opened. Then, the first fuel is not injected, and the second needle valve 46 rises and the second fuel is injected. After that, the solenoid valve 89 as the second fuel solenoid valve is closed. Then, the second needle valve 46 descends and the injection of the second fuel stops.

[0058] [Second Embodiment] FIG. 10 is a schematic configuration diagram showing a fuel injection device according to the second embodiment. Note that members having the same functions as those in the first embodiment described above are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0059] <Configuration of Fuel Injection Device> As shown in FIG. 10, the fuel injection device 14A includes a fuel supply device 31, a fuel supply passage 32, and a fuel injection valve 33A. The fuel supply device 31 has a first fuel supply device 41 and a second fuel supply device 42. The fuel supply passage 32 has a first fuel supply passage 43 and a second fuel supply passage 44. The fuel injection valve 33A has a first needle valve 45 and a second needle valve 46. The fuel injection device 14A of the second embodiment does not include a spool valve mechanism 47 and a piston mechanism 48 with respect to the fuel injection device 14 of the first embodiment, and the first fuel supply passage 43 and the second fuel supply passage 44 are provided independently.

[0060] The first fuel supply device 41 pressurizes, for example, the first fuel in the common rail to a predetermined pressure and supplies it to the first fuel supply passage 43. The second fuel supply device 42 pressurizes, for example, the second fuel to a predetermined pressure and supplies it to the second fuel supply passage 44. The first fuel supply device 41 and the second fuel supply device 42 are substantially the same as those in the first embodiment.

[0061] In the fuel injection valve 33A, the first needle valve 45 and the second needle valve 46 are supported so as to be movable in the longitudinal direction with respect to the main body 51. The fuel injection valve 33A is provided with a plurality of first nozzles 52 and a plurality of second nozzles 53 at the tip end portion (the lower end portion in FIG. 10). The fuel injection valve 33A is provided with a first control chamber 67 between the base end portion of the main body 51 (the upper end portion in FIG. 10) and the base end portion of the first needle valve 45 (the upper end portion in FIG. 10). Further, the fuel injection valve 33A is provided with a second control chamber 151 between the intermediate portion of the main body 51 and the base end portion of the second needle valve 46 (the upper end portion in FIG. 10).

[0062] The first fuel supply path 43 has a first branch path 71 communicating with the first control chamber 67 of the fuel injection valve 33A, and a second branch path 72 communicating with the first fuel flow path 64 of the first needle valve 45. And a throttle 70 is provided in the first branch path 71 of the first fuel supply path 43. The fuel injection valve 33A has a first drain path 75 communicating with the first control chamber 67 at the base end portion of the main body 51, and the first drain path 75 is provided with a first electromagnetic valve (first on-off valve) 69. Also, in the second fuel supply path 44, a first branch path 73 communicates with the second control chamber 151 of the fuel injection valve 33A, and a second branch path 74 communicates with the third chamber 56 of the main body 51. And a throttle 152 is provided in the first branch path 73 of the second fuel supply path 44. The fuel injection valve 33A has a second drain path 153 communicating with the second control chamber 151 in the middle portion of the main body 51 via the first branch path 73, and the second drain path 153 is provided with a second electromagnetic valve (second on-off valve) 154.

[0063] The control device 105 is connected to the electromagnetic valves 69, 154. The control device 105 controls the opening and closing timing of the electromagnetic valves 69, 154 to adjust the injection timing and injection amount of the first fuel and the second fuel from the fuel injection valve 33A.

[0064] <Operation of the fuel injection device> When the first electromagnetic valve 69 is closed (non-energized), the first needle valve 45 is in close contact with the second needle valve 46 by the biasing force of the biasing spring 63, and the second needle valve 46 is in close contact with the main body 51. In this state, the first fuel at a predetermined pressure is supplied from the first fuel supply path 43 to the first control chamber 67 via the first branch path 71 by the first fuel supply device 41, and is also supplied to the first fuel flow path 64 of the first needle valve 45 via the second branch path 72. When the first electromagnetic valve 69 is in the closed state, the first needle valve 45 is in the lowered position biased downward by the biasing force of the biasing spring 63 and the supply pressure of the first fuel to the first control chamber 67, and the communication between the first fuel flow path 64 of the first needle valve 45 and the second fuel flow path 66 of the second needle valve 46 is blocked by the first seat portion S1, and the injection of the first fuel from the first nozzle 52 is stopped.

[0065] Further, in this state, the fuel injection valve 33A has second fuel at a predetermined pressure supplied from the second fuel supply device 42 to the second control chamber 151 through the first branch passage 73 in the second fuel supply passage 44, and supplied to the third chamber 56 of the main body 51 through the second branch passage 74. When the second solenoid valve 154 is in the closed state, the second needle valve 46 is in the lowered position biased downward by the biasing force of the biasing spring 63 and the supply pressure of the second fuel to the second control chamber 151, and the communication between the second chamber 55, the third chamber 56 of the main body 51, and the second fuel passage 66 is blocked by the second seat portion S2 and the third seat portion S3, and the injection of the second fuel from the first nozzle 52 and the second nozzle 53 is stopped.

[0066] On the other hand, when the first solenoid valve 69 is opened (energized), the first fuel in the first control chamber 67 is discharged from the first drain passage 75. The first needle valve 45 is in the raised position moved upward by the supply pressure of the first fuel to the first fuel passage 64, and when the first seat portion S1 is opened, the first fuel passage 64 of the first needle valve 45 and the second fuel passage 66 of the second needle valve 46 are communicated, and the first fuel is injected from the first nozzle 52. Further, when the second solenoid valve 153 is opened (energized), the second fuel in the second control chamber 151 is discharged from the second drain passage 153. The second needle valve 46 is in the raised position moved upward by the supply pressure of the second fuel to the third chamber 56, and when the second seat portion S2 and the third seat portion S3 are opened, the third chamber 56, the second chamber 55, and the first chamber 54 of the main body 51 are communicated, and the second fuel is injected from the first nozzle 52 and the second nozzle 53. At this time, the first seat portion S1 is closed, the flow of the first fuel from the first fuel passage 64 of the first needle valve 45 to the second fuel passage 66 of the second needle valve 46 is blocked, and the injection of the first fuel from the plurality of first nozzles 52 is stopped.

[0067] [Third Embodiment] FIG. 11 is a schematic configuration diagram showing the fuel injection device of the third embodiment. Note that members having the same functions as those in the above-described first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

[0068] [Configuration of Fuel Injection Device]< As shown in FIG. 11, the fuel injection device 14B includes a fuel supply device 31, a fuel supply passage 32, and a fuel injection valve 33B. The fuel supply device 31 has a first fuel supply device 41 and a second fuel supply device 42. The fuel supply passage 32 has a first fuel supply passage 43 and a second fuel supply passage 44. The fuel injection valve 33B has a first needle valve 45 and a second needle valve 46. The fuel injection device 14B of the third embodiment is substantially the same as the fuel injection device 14A of the second embodiment.

[0069] In the first fuel supply passage 43, a first branch passage 71 communicates with a first control chamber 67 of the fuel injection valve 33B. Also, in the first fuel supply passage 43, a second branch passage 72 communicates with a first fuel flow passage 64 of the first needle valve 45. Further, in the first fuel supply passage 43, a third branch passage 155 branched from the second branch passage 72 communicates with a second drain passage 153, and a throttle 156 is provided in the third branch passage 155. And in the fuel injection valve 33B, a second drain passage 153 with which the third branch passage 155 communicates communicates with a second control chamber 151 in the middle part of the main body 51, and a second electromagnetic valve (second on-off valve) 154 is provided in the second drain passage 153. Also, the second fuel supply passage 44 communicates with a third chamber 56 of the main body 51.

[0070] In the fuel injection valve 33B, first fuel at a predetermined pressure is supplied from the first fuel supply device 41 to the second control chamber 151 through the first fuel supply passage 43, the second branch passage 72, and the third branch passage 155.

[0071] <Fuel injection timing> FIG. 12 is a time chart showing the operation of the fuel injection device. The time chart in FIG. 12 illustrates the operations of the fuel injection device 14A of the second embodiment and the fuel injection device 14B of the third embodiment.

[0072] As shown in FIGS. 10 to 12, the pressure of the second fuel (e.g., 100 MPa) supplied to the fuel injection valves 33A and 33B through the second fuel supply passage 44 by the second fuel supply device 42 is constant. When the first solenoid valve 69 is opened, the first fuel in the first control chamber 67 is discharged and the pressure decreases in the fuel injection valves 33A and 33B. At this time, the first needle valve 45 moves and the lift amount increases. After a predetermined time, when the second solenoid valve 154 is opened in the fuel injection valve 33A, the second fuel in the second control chamber 151 is discharged and the pressure decreases. Also, after a predetermined time, when the second solenoid valve 154 is opened in the fuel injection valve 33B, the first fuel in the second control chamber 151 is discharged and the pressure decreases. At this time, the second needle valve 46 moves and the lift amount increases.

[0073] During the period from when the first needle valve 45 moves and the lift amount increases until the second needle valve 46 moves and the lift amount increases in the fuel injection valves 33A and 33B, the first seat portion S1 is opened, the first fuel in the first fuel passage 64 is supplied to the first chamber 54 through the second fuel passage 66, and the first fuel is injected from the first nozzle 52. Then, after the second needle valve 46 moves and the lift amount increases in the fuel injection valves 33A and 33B, the first seat portion S1 is closed and the injection of the first fuel from the first nozzle 52 stops. Then, in the fuel injection valve 33A, the second seat portion S2 is opened, the second fuel in the third chamber 56 is supplied to the second chamber 55, the second fuel in the second chamber 55 is supplied to the first chamber 54, and the second fuel is injected from the first nozzle 52 and the second nozzle 53.

[0074] Thereafter, when the second solenoid valve 154 is closed in the fuel injection valves 33A and 33B, the discharge of the second fuel from the second control chamber 151 stops and the pressure increases. At this time, the second needle valve 46 moves and the lift amount decreases. After a predetermined time, when the first solenoid valve 69 is closed in the fuel injection valves 33A and 33B, the discharge of the first fuel from the first control chamber 57 stops and the pressure increases. At this time, the first needle valve 45 moves and the lift amount decreases.

[0075] When the second needle valve 46 moves and the lift amount decreases, the second seat portion S2 is closed in the fuel injection valves 33A and 33B, and the injection of the second fuel from the first nozzle 52 and the second nozzle 53 stops. The fuel injection valves 33A and 33B inject the first fuel from the first nozzle 52 during the period from when the second needle valve 46 moves and the lift amount decreases until the first needle valve 45 moves and the lift amount decreases, during which the first seat portion S1 is opened. Then, when the first needle valve 45 moves and the lift amount decreases, the first seat portion S1 is closed in the fuel injection valves 33A and 33B, and the injection of the first fuel from the first nozzle 52 stops.

[0076] [Operation and Effect of the Present Embodiment] The fuel injection device according to the first aspect includes a first fuel supply path 43 that supplies a first fuel having a predetermined ignitability, a second fuel supply path 44 that supplies a second fuel having a lower ignitability than the first fuel, and fuel injection valves 33 and 33A to which the first fuel supply path 43 and the second fuel supply path 44 are connected. The fuel injection valves 33 and 33A include a main body 51 provided with nozzles 52 and 53 at the tip, a first needle valve 45 that is movably provided inside the main body 51 and the first fuel supply path 43 can communicate with the nozzle 52 according to the movement position, and a second needle valve 46 that is movably provided between the main body 51 and the first needle valve 45 and the second fuel supply path 44 can communicate with the nozzles 52 and 53 according to the movement position. The main body 51, the first needle valve 45, and the second needle valve 46 are concentric. When the first needle valve 45 moves away from the second needle valve 46, the first fuel supply path 43 communicates with the nozzle 52 to inject the first fuel. When the second needle valve 46 moves away from the main body 51, the second fuel supply path 44 communicates with the nozzles 52 and 53 to inject the second fuel.

[0077] According to the fuel injection device according to the first aspect, the first fuel can be injected from the nozzle 52 by the movement of the first needle valve 45 with respect to the main body 51, the second fuel can be injected from the nozzles 52 and 53 by the movement of the second needle valve 46, and the ignitability of the fuel can be improved.

[0078] The fuel injection device according to the second aspect is the fuel injection device according to the first aspect, further comprising a first nozzle 52 positioned at intervals in the circumferential direction, and a second nozzle 53 positioned at intervals in the circumferential direction at a position shifted in the circumferential direction or the axial direction with respect to the first nozzle 52. The first fuel supply passage 43 can communicate with the first nozzle 52, and the second fuel supply passage 44 can communicate with the first nozzle 52 and the second nozzle 53. Thereby, by injecting a large amount of the second fuel with poor ignitability from the first nozzle 52 and the second nozzle 53 and injecting a small amount of the first fuel with good ignitability from the first nozzle 52, the ignitability of the second fuel can be enhanced.

[0079] The fuel injection device according to the third aspect is the fuel injection device according to the first aspect or the second aspect, further comprising: the first needle valve 45 has a first fuel flow passage 64 extending along the axial direction and having a base end portion communicating with the first fuel supply passage 43 and a tip end portion opening; the second needle valve 46 has a second fuel flow passage 66 penetrating along the axial direction; and a first seat portion S1 is provided between the tip end portion of the first fuel flow passage 64 and the base end portion of the second fuel flow passage 66. Thereby, the injection and stop of the first fuel can be appropriately performed by the movement of the first needle valve 45.

[0080] The fuel injection device according to the fourth aspect is the fuel injection device according to the third aspect, further comprising: the main body 51 has a first chamber 54 in which the first nozzle 52 is formed, a second chamber 55 in which the second nozzle is formed, and a third chamber 56 with which the second fuel supply passage 44 communicates; a second seat portion S2 is provided between the second chamber 55 and the third chamber 56; the first seat portion S1 can be opened and closed according to the movement of the first needle valve 45; and the second seat portion S2 can be opened and closed according to the movement of the second needle valve 46. Thereby, the injection and stop of the second fuel can be appropriately performed by the movement of the second needle valve 46.

[0081] The fuel injection device according to the fifth aspect is the fuel injection device according to the fourth aspect, further comprising: a third seat portion S3 is provided between the second chamber 55 and the second fuel flow passage 66; and the third seat portion S3 can be opened and closed according to the movement of the second needle valve 46. Thereby, the injection and stop of the second fuel can be appropriately performed by the movement of the second needle valve 46.

[0082] The fuel injection device according to the sixth aspect is a fuel injection device according to any one of the first to fifth aspects, and further, when the first needle valve 45 and the second needle valve 46 are in the lowered positions, the first fuel supply passage 43 and the second fuel supply passage 44 do not communicate with the nozzles 52, 53, and when the first needle valve 45 is in the raised position, the first fuel supply passage 43 communicates with the nozzle 52, and when the second needle valve 46 is in the raised position, the second fuel supply passage 44 communicates with the nozzles 52, 53. Thereby, the first fuel and the second fuel can be selectively injected from the nozzles 52, 53 according to the moving positions of the first needle valve 45 and the second needle valve 46.

[0083] The fuel injection device according to the seventh aspect is a fuel injection device according to any one of the first to sixth aspects, and further, has a supply port 83 for the first fuel and a discharge port 84 for the first fuel that communicate with the first fuel supply passages 43, 43A, and a spool valve mechanism 47, 47A having a supply and discharge port 85 that communicates with the supply port 83 or the discharge port 84 according to the moving position of the valve bodies 82, 82A, and a piston mechanism 48 in which the second fuel supply passage 44 communicates with one side in the moving direction of the piston 102 and the supply and discharge port 85 communicates with the other side in the moving direction of the piston 102 via a communication passage 93. Thereby, by switching the communication relationship between the supply port 83, the discharge port 84, and the supply and discharge port 85 by the spool valve mechanisms 47, 47A, the storage stroke of the second fuel and the injection strokes of the first fuel and the second fuel by the fuel injection valves 33, 33A can be alternately performed. That is, the first fuel and the second fuel are not mixed on the way and are supplied to the fuel injection valves 33, 33A. As a result, by suppressing the mixing of the first fuel and the second fuel, highly accurate fuel injection can be enabled and harmful substances contained in the exhaust gas can be reduced.

[0084] The fuel injection device according to the eighth aspect is the fuel injection device according to the seventh aspect, and further, in the spool valve mechanism 47, a first communication path 86a from the first fuel supply path 86 communicates with one side in the moving direction of the valve body 82, a second communication path 86b from the first fuel supply path 86 communicates with the other side, and a drain path 88 communicates therewith, and a solenoid valve (on-off valve) 89 is provided in the drain path 88. Thereby, in the closed state of the solenoid valve 89, the first discharge port 84 and the first supply / discharge port 85 communicate with each other, the first fuel of the piston mechanism 48 is discharged from the communication path 93, and the piston 102 can be moved to store the second fuel. On the other hand, in the open state of the solenoid valve 89, the supply port 83 and the first supply / discharge port 85 communicate with each other, the first fuel in the first fuel supply path 86 is supplied from the communication path 93 to the piston mechanism 48, and the piston 102 can be moved to discharge the second fuel.

[0085] The fuel injection device according to the ninth aspect is the fuel injection device according to any one of the first aspect to the eighth aspect, and further, in the first needle valve 45, a first control chamber 67 is provided on the base end side, the first fuel supply path 43 communicates with the first control chamber 67, and the first drain path 75 communicates therewith. A first solenoid valve (first on-off valve) 69 is provided in the first drain path 75. In the second needle valve 46, a second control chamber 151 is provided on the base end side, the second fuel supply path 44 communicates with the second control chamber 151, and the second drain path 153 communicates therewith. A second solenoid valve (second on-off valve) 154 is provided in the second drain path 153. Thereby, the injection of the first fuel and the injection of the second fuel can be appropriately switched by the first solenoid valve 69 and the second solenoid valve 154.

[0086] The fuel injection device according to the 10th aspect is a fuel injection device according to any one of the 1st to 5th aspects, and further, the first needle valve 45 is provided with a first control chamber 67 on the base end side, the first fuel supply path 43 communicates with the first control chamber 67 and the first drain path 75 also communicates therewith, a first electromagnetic valve (first on-off valve) 69 is provided in the first drain path 75, the second needle valve 46 is provided with a second control chamber 151 on the base end side, the first fuel supply path 43 communicates with the second control chamber 151 and the second drain path 153 also communicates therewith, and a second electromagnetic valve (second on-off valve) 154 is provided in the second drain path 153. Thereby, the injection of the first fuel and the injection of the second fuel can be appropriately switched by the first electromagnetic valve 69 and the second electromagnetic valve 154.

[0087] The reciprocating internal combustion engine according to the 11th aspect includes an engine body 11 having a combustion chamber 25 and fuel injection devices 14, 14A, 14B according to any one of the 1st to 9th aspects that inject fuel into the combustion chamber 25. Thereby, the first fuel can be injected from the nozzle 52 by the movement of the first needle valve 45 with respect to the main body 51, the second fuel can be injected from the nozzles 52, 53 by the movement of the second needle valve 46, and the ignition property of the fuel can be improved.

Explanation of Reference Numerals

[0088] 10 Engine (reciprocating internal combustion engine) 11 Engine body (internal combustion engine body) 12 Intake passage 13 Exhaust passage 14, 14A, 14B Fuel injection device 21 Combustion chamber 22 Intake port 23 Exhaust port 31 Fuel supply device 32 Fuel supply path 33, 33A Fuel injection valve 41 First fuel supply device 42 Second fuel supply device 43 First fuel supply path 44 Second fuel supply path 45 First needle valve 46 Second Needle Valve 47 Spool Valve Mechanism 48 Piston Mechanism 51 Main Body 52 First Nozzle 53 Second Nozzle 54 First Chamber 55 Second Chamber 56 Third Chamber 64 First Fuel Flow Path 66 Second Fuel Flow Path 67 Control Chamber, First Control Chamber 68 Check Valve 69 Solenoid Valve, First Solenoid Valve (First On - Off Valve) 75 Drain Path, First Drain Path 80 Spool Valve 81 Casing 82 Valve Body 83 Supply Port 84 Discharge Port 85 Supply - Discharge Port 86 First Fuel Supply Path 87 Throttle 88 Drain Path 89 Solenoid Valve (On - Off Valve) 91 Return Path 92 Check Valve 93 Communication Path 94 Return Path 101 Cylinder 102 Piston 102a First Pressure - Receiving Surface 102b Second Pressure - Receiving Surface 103 First Storage Portion 104 Second Storage Portion 105 Control Device 151 Second Control Chamber 153 Second Drain Path 154 Second Solenoid Valve (Second On - Off Valve) S1 First Seat Portion S2 Second Seat Portion S3 Third Seat Portion

Claims

1. a first fuel supply path for supplying a first fuel having a predetermined ignition property; a second fuel supply path for supplying a second fuel having a lower ignition ability than the first fuel; a fuel injection valve to which the first fuel supply path and the second fuel supply path are connected; Equipped with The fuel injection valve includes a main body having a nozzle at a tip end thereof; a first needle valve that is movably provided inside the main body and that can connect the first fuel supply path to the nozzle depending on a moving position of the first needle valve; a second needle valve that is movably provided between the main body and the first needle valve and that can connect the second fuel supply path to the nozzle depending on a moving position of the second needle valve; having the main body, the first needle valve, and the second needle valve are concentric; when the first needle valve moves away from the second needle valve, the first fuel supply path communicates with the nozzle to inject the first fuel, and when the second needle valve moves away from the main body, the second fuel supply path communicates with the nozzle to inject the second fuel. Fuel injection device.

2. the nozzle has a first nozzle located at an interval in a circumferential direction and a second nozzle located at a position shifted in the circumferential direction or the axial direction from the first nozzle and spaced apart in the circumferential direction, the first fuel supply path can be communicated with the first nozzle, and the second fuel supply path can be communicated with the first nozzle and the second nozzle.

2. The fuel injection system of claim 1.

3. the first needle valve has a first fuel flow passage extending along an axial direction, a base end of the first fuel flow passage communicating with the first fuel supply path and an open tip end, the second needle valve has a second fuel flow passage passing through the second needle valve along an axial direction, and a first seat portion is provided between the tip end of the first fuel flow passage and the base end of the second fuel flow passage.

3. A fuel injection system according to claim 2.

4. the main body has a first chamber in which the first nozzle is formed, a second chamber in which the second nozzle is formed, and a third chamber to which the second fuel supply path is connected, a second seat portion is provided between the second chamber and the third chamber, the first seat portion can be opened and closed in response to movement of the first needle valve, and the second seat portion can be opened and closed in response to movement of the second needle valve; 4. A fuel injection system according to claim 3.

5. a third seat portion is provided between the second chamber and the second fuel flow passage, and the third seat portion is capable of opening and closing in response to movement of the second needle valve; 5. A fuel injection system according to claim 4.

6. when the first needle valve and the second needle valve are in their lowered positions, the first fuel supply path and the second fuel supply path do not communicate with the first nozzle hole, when the first needle valve is in their raised position, the first fuel supply path communicates with the first nozzle hole, and when the second needle valve is in their raised position, the second fuel supply path communicates with the first nozzle hole and the second nozzle hole.

5. A fuel injection system according to claim 4.

7. a spool valve mechanism having a supply port of the first fuel communicating with the first fuel supply path and a discharge port of the first fuel, the supply port being connected to the supply port or the discharge port depending on a moving position of a valve body; a piston mechanism in which one side of a piston in a moving direction is connected to the second fuel supply path and the other side of the piston in the moving direction is connected to the supply / discharge port via a communication path; A fuel injection system according to any one of claims 1 to 6, comprising:

8. the spool valve mechanism has one side in a moving direction of a valve body connected to a first communication path from the first fuel supply path, and the other side connected to a second communication path from the first fuel supply path and a drain path, and an opening / closing valve is provided in the drain path; 8. A fuel injection system according to claim 7.

9. the first needle valve has a first control chamber provided at a base end thereof, the first control chamber communicates with the first fuel supply path and a first drain path, and a first on-off valve is provided in the first drain path; the second needle valve has a second control chamber provided at a base end thereof, the second control chamber communicates with the second fuel supply path and a second drain path, and a second on-off valve is provided in the second drain path; A fuel injection device according to any one of claims 3 to 6.

10. the first needle valve has a first control chamber provided at a base end thereof, the first control chamber communicates with the first fuel supply path and a first drain path, and a first on-off valve is provided in the first drain path; the second needle valve has a second control chamber provided at a base end thereof, the second control chamber communicates with the first fuel supply path and a second drain path, and a second on-off valve is provided in the second drain path; A fuel injection device according to any one of claims 3 to 6.

11. An internal combustion engine body having a combustion chamber; A fuel injection device according to claim 1 for injecting fuel into the combustion chamber; A reciprocating internal combustion engine comprising:

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