Fuel injection device and reciprocating internal combustion engine

Abstract

To enable accurate fuel injection by suppressing mixture of first fuel and second fuel and reduce harmful substances included in an exhaust gas 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 supply second fuel with ignitability lower than that of the first fuel; a fuel injection valve to which the first fuel supply passage and the second fuel supply passage are connected; a spool valve system having a supply port for the first fuel communicating with the first fuel supply passage, a first discharge port for the first fuel and a first supply / discharge port communicating with the supply port or the first discharge port in accordance with a movement position of a valve element; and a piston mechanism in which the second fuel supply passage communicates with one side in the movement direction of the piston and the first supply / discharge port communicates with the other side in the movement direction of the piston via a communication passage.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 harmful substances (for example, carbon dioxide, etc.) generated. 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 multiple types of fuels, for example, there is one described in Patent Document 1 below. The fuel injection device described in Patent Document 1 injects fossil fuel as the first fuel and alternative fuel as the second fuel in layers.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional fuel injection device, a fuel pump that pumps the first fuel is connected to a fuel injection valve via a fuel injection pipe, and an injection pump that pumps the second fuel is connected to the fuel injection valve via an injection pipe. The conventional fuel injection device has a problem that, with such a configuration, the first fuel and the second fuel are likely to be mixed when switching fuels, and it is difficult to adjust the injection ratio of the first fuel and the second fuel with high accuracy.

[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 enable highly accurate fuel injection by suppressing mixing of a first fuel and a second fuel, thereby reducing harmful substances contained in exhaust gas.

Means for Solving the Problems

[0006] The fuel injection device of the present disclosure for achieving the above object includes a first fuel supply path that supplies a first fuel having a predetermined ignitability, a second fuel supply path that supplies a second fuel having a lower ignitability than the first fuel, a fuel injection valve to which the first fuel supply path and the second fuel supply path are connected, a supply port of the first fuel that communicates with the first fuel supply path and a first discharge port of the first fuel, and a spool valve mechanism having a first supply / discharge port that communicates with the supply port or the first discharge port according to a moving position of a valve body, and a piston mechanism in which the second fuel supply path communicates with one side in the moving direction of the piston and the first supply / discharge port communicates with the other side in the moving direction of the piston via a communication path.

[0007] 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 that injects 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, by suppressing mixing of the first fuel and the second fuel, highly accurate fuel injection can be enabled, and harmful substances contained in exhaust gas can be reduced.

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

DETAILED DESCRIPTION OF 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 embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those within a so-called equivalent range.

[0011] [First Embodiment] [Engine] FIG. 1 is a schematic diagram showing the 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 to each combustion chamber 21 from each intake port 22. The exhaust passage 13 discharges the combustion gas burned in each combustion chamber 21, that is, the exhaust gas, to the outside from each exhaust port 23.

[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 ignites 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 the 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 a lower (worse) ignitability than the first fuel. Here, the ignitability is 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] In the fuel injection valve 33, a first needle valve 45 and a second needle valve 46 are supported by the main body 51 so as to be movable in the longitudinal direction. In FIG. 2, the intermediate portion of the main body 51 is omitted. At the tip (the lower end in FIG. 2) of the main body 51, a first nozzle 52 and a second nozzle 53 are provided at different radial positions. A plurality of first nozzles 52 are provided at intervals in the circumferential direction on the tip side of the main body 51. A plurality of second nozzles 53 are provided at intervals in the circumferential direction on the base end side (the upper end in FIG. 2) of the main body 51 with respect to the first nozzle 52. The plurality of first nozzles 52 communicate with a first chamber 54, and the second nozzle 53 communicates with a second chamber 55. Further, the main body 51 is provided with a third chamber 56 on the upper end side of 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 by the main body 51 so as to be relatively movable. 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 of the first needle valve 45 is in close contact with the inner surface of the tip of the second needle valve 46, and the outer surface of the tip 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 a 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 a 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 a third seat portion S3.

[0024] The first fuel supply passage 43 branches at its downstream end into two branch passages 71 and 72. The first branch passage 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 passage 72 communicates with the first fuel flow passage 64 of the first needle valve 45. The second fuel supply passage 44 branches at its downstream end into two branch passages 73 and 74. The first branch passage 73 has its downstream end communicating with the piston mechanism 48. The second branch passage 74 communicates with the third chamber 56 of the main body 51. A check valve 68 is provided upstream of the branch passages 73 and 74 in the second fuel supply passage 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 passage 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 passage 75. Furthermore, a throttle 70 is provided in the first branch passage 71 of the first fuel supply passage 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 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 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 flow 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 flow passage 64 of the first needle valve 45 and the second fuel flow 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 flow 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 is provided 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 the 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 the 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 the return path 94 via a check valve 92. The check valve 92 prevents the backflow of the first fuel toward 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 includes 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 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 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 side of the communication passage 93, and a second pressure receiving surface 102b formed on the side of the first branch passage 73. The first fuel supply pressure from the communication 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. 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 communication passage 93 on the side of the first pressure receiving surface 102a to store the first fuel, and a second storage portion 104 that communicates with the first branch passage 73 on the side of the second pressure receiving surface 102b to store the second fuel. The piston 102 has a rod portion 102c. The area of the first pressure receiving surface 102a of the piston 102 is smaller than the area of the second pressure receiving surface 102b by 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 side of the communication passage 93, 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 for 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 for 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 a second fuel supply path 44. The common rail 42B is connected to the fuel injection valve 33 and is also connected to a piston mechanism 48. 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. A recovery path 125 for 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 a main part of the fuel injection valve, and FIG. 5 is a schematic view showing a 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 center 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 is disposed inside the second needle valve 46. A first seat 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 seat portion S1 is provided in a ring shape between the storage portion 65a and the inclined surface 65b.

[0044] Also, a second seat portion S2 is provided between the second chamber 55 and the third chamber 56 of the main body 51. Further, a third seat 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. Further, 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 seat portion S2 is provided in a ring shape between the inclined surface 65c and the second chamber 55, and the third seat 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 causes the first needle valve 45 to descend as described above, 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 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, set the pressure of the second fuel in the second fuel supply path 44 to 10 MPa and the pressure of the first fuel in the return path 94 to 11 MPa, and set the area ratio of the first pressure receiving surface 102a and the second pressure receiving surface 102b on the piston 102 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 to 12 MPa by the piston 102, making it higher than the pressure of the first fuel in the return path 94 and opening the check valve 92, allowing the piston 102 to rise to the top dead center.

[0050] As shown in FIG. 7, when the solenoid valve 69 is opened (energized), the fuel injection valve 33 has the first fuel in the control chamber 67 discharged from the drain path 75, and the first needle valve 45 moves upward due to 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 passage 88, and the valve body 82 moves toward the drain passage 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 passage 86 flows through the spool valve 80 into the communication passage 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 passage 73 side. Then, the piston mechanism 48 supplies the second fuel in the second storage portion 104 to the first branch passage 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 passage 73, the pressure of the second fuel in the first branch passage 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 contacts 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 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 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 is stopped, and then, the first needle valve 45 descends and the injection of the first fuel is stopped. 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 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 32A, and a fuel injection valve 33A. The fuel supply passage 32A has a first fuel supply passage 43A and a second fuel supply passage 44. The fuel injection valve 33A has a needle valve 151. The fuel injection device 14A also includes a spool valve mechanism 47A and a piston mechanism 48.

[0060] The fuel injection device 14A can inject a first fuel having a predetermined ignitability and can also inject a second fuel having lower ignitability (worse) than the first fuel. The fuel supply device 31 is the same as that in the first embodiment and has a first fuel supply device 41 and a second fuel supply device 42.

[0061] In the fuel injection valve 33A, the needle valve 151 is supported by the main body 152 so as to be movable in the longitudinal direction. The main body 152 is provided with a nozzle 153 at its tip. A plurality of nozzles 153 are provided at intervals in the circumferential direction on the tip side of the main body 152. The plurality of nozzles 153 communicate with a chamber 154. The needle valve 151 has a cylindrical shape and includes a valve body 155, a flange portion 156, and a biasing spring (biasing member) 157. The needle valve 151 is disposed inside the main body 152 and is supported so as to be relatively movable with respect to the main body 152. The biasing force of the biasing spring 157 acts on the needle valve 151 via the flange portion 156 by the valve body 155. The needle valve 151 is biased downward and is biased and supported by the main body 152. Therefore, the outer surface of the tip of the needle valve 151 is in close contact with the inner surface of the main body 152. At this time, the nozzle 153 and the chamber 154 are blocked by the seat portion S3.

[0062] The first fuel supply path 43A is connected to the fuel injection valve 33A via the spool valve mechanism 47A. The second fuel supply path 44 has the first branch path 73 communicating with the piston mechanism 48 and the second branch path 74 communicating with the chamber 154 of the main body 152 in the fuel injection valve 33A. A check valve 68 is provided in the second fuel supply path 44.

[0063] Therefore, in the fuel injection valve 33A, the needle valve 151 is in close contact with the main body 152 by the biasing force of the biasing spring 157. In this state, in the fuel injection valve 33A, the nozzle 153 and the chamber 154 are blocked by the seat portion S3, and the injection of the first fuel and the second fuel from the nozzle 153 is stopped. On the other hand, in the fuel injection valve 33A, when the needle valve 151 moves upward, the seat portion S3 is opened, so that the nozzle 153 and the chamber 154 communicate with each other, and the first fuel or the second fuel is injected from the nozzle 153.

[0064] The spool valve mechanism 47A has a spool valve 80A. The spool valve 80A has a casing 81A and a valve body 82A. The casing 81A has a hollow cylindrical shape, and the valve body 82A has a string shape in which three spools 82a, 82b, 82d having a cylindrical shape are connected by connecting portions 82c, 82e. In the spool valve 80A, a supply port 83, a first discharge port 84, and a second discharge port 161 are provided on one side of the casing 81A, and a first supply / discharge port 85 and a second supply / discharge port 162 are provided on the other side. When the valve body 82A is located on one (lower in FIG. 10) side, the first discharge port 84 and the first supply / discharge port 85 communicate with each other, and the supply port 83 and the second supply / discharge port 162 communicate with each other in the spool valve 80A. When the valve body 82A is located on the other (upper in FIG. 10) side, the supply port 83 and the first supply / discharge port 85 communicate with each other, and the second discharge port 161 and the second supply / discharge port 162 communicate with each other in the spool valve 80A.

[0065] The first fuel supply path 43A branches downstream into three communication paths 43a, 43b, and 43c. The spool valve 80A has the downstream end of the first communication path 43a communicating with the spool 82d side of the valve body 82A, and the downstream end of the second communication path 43b communicating with the spool 82b side of the valve body 82A. The first communication path 43a is provided with a throttle 87. Also, the spool valve 80A has a drain path 88 communicating with the spool 82d side of the valve body 82A, and the drain path 88 is provided with an electromagnetic valve (on-off valve) 89.

[0066] The spool valve mechanism 47A has the third communication path 43c connected to the supply port 83. Also, the spool valve mechanism 47A has a return path 91 connected to the first discharge port 84. The return path 91 is provided with an electromagnetic valve (on-off valve) 163. Also, the spool valve mechanism 47A has a communication path 164 connected to the return path 91 and connected to the second discharge port 161. Further, the spool valve mechanism 47A has a communication path 93 connected to the first supply / discharge port 85 and communicating with the piston mechanism 48, and a communication path 165 connected to the second supply / discharge port 162 and communicating with the control chamber 158 of the fuel injection valve 33A.

[0067] The piston mechanism 48 is provided between the first fuel supply path 43A 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 columnar shape. The piston mechanism 48 has the communication path 93 from the spool valve mechanism 47A communicating with the first storage portion 103, and the first branch path 73 of the second fuel supply path 44 communicating with the second storage portion 104. Also, the piston mechanism 48 and the second branch path 74 of the second fuel supply path 44 communicate with each other through the first fuel injection path 166. The first fuel injection path 166 communicates with an intermediate portion in the longitudinal direction of the cylinder 101 (the moving direction of the piston 102) in the piston mechanism 48.

[0068] Therefore, when the solenoid valve 89 is in the closed state, the second fuel in the second fuel supply path 44 is supplied to the second storage portion 104 of the piston mechanism 48 through the check valve 68. At this time, in the spool valve mechanism 47A, the first discharge port 84 and the first supply / discharge port 85 communicate with each other, and the supply port 83 and the second supply / discharge port 162 communicate with each other. Here, in the piston mechanism 48, the piston 102 moves to the communication path 93 side, the first fuel in the first storage portion 103 is discharged to the return path 91 through the spool valve mechanism 47A, and a predetermined amount of the second fuel is stored in the second storage portion 104. Further, since the spool valve mechanism 47A supplies the first fuel in the first fuel supply path 43A to the control chamber 158 of the fuel injection valve 33A, the needle valve 151 of the fuel injection valve 33A descends, and the injection of the first fuel and the second fuel is stopped.

[0069] On the other hand, when the solenoid valve 89 is in the open state, in the spool valve mechanism 47A, the first fuel supplied to the spool 82d side is discharged from the drain path 88, and the valve body 82A of the spool valve 80A moves to the drain path 88 side. At this time, in the spool valve mechanism 47A, the supply port 83 and the first supply / discharge port 85 communicate with each other, the first fuel is supplied to the first storage portion 103 of the piston mechanism 48 through 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 fuel injection valve 33A through the branch paths 73 and 74.

[0070] And when the valve body 82A of the spool valve 80A moves to the drain path 88 side in the spool valve mechanism 47A, the second discharge port 161 and the second supply / discharge port 162 communicate with each other, and the first fuel in the control chamber 158 is discharged to the return path 91 through the communication paths 165 and 164. Then, in the fuel injection valve 33A, the needle valve 151 rises due to the supply pressure of the second fuel supplied to the chamber 154, and the first fuel and the second fuel are injected.

[0071] The control device 105 is connected to the solenoid valves 89 and 163. By controlling the opening and closing timing of the solenoid valves 89 and 163, the control device 105 adjusts the injection timing and injection amount of the first fuel and the second fuel from the fuel injection valve 33A. Further, a position sensor 106 is provided in the piston mechanism 48, and the position sensor 106 detects the moving position of the piston 102. The control device 105 is connected to the position sensor 106. The control device 105 controls the opening and closing of the solenoid valve 163 based on the detection result of the position sensor 106, and adjusts the amount of the second fuel stored in the second storage portion 104 by opening and closing the solenoid valve 163.

[0072] <Operation of Fuel Injection Device> FIG. 11 is a schematic configuration diagram showing the fuel injection state by the fuel injection device.

[0073] As shown in FIG. 10, when the solenoid valve 89 is closed (non-energized), the first fuel in the first fuel supply path 43A is supplied to the control chamber 158 of the fuel injection valve 33A in the spool valve mechanism 37A. When the needle valve 151 descends, the communication between the chamber 154 and the nozzle 153 is blocked by the seat portion S3, and the first fuel and the second fuel are not injected from the nozzle 153.

[0074] At this time, when the solenoid valve 163 is opened (energized), the second fuel in the second fuel supply path 44 is supplied to the second storage portion 104 of the piston mechanism 48. Here, in the piston mechanism 48, 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 102b. In the spool valve mechanism 47A, the first discharge port 84 and the first supply / discharge port 85 communicate with each other, and the first fuel is discharged to the return path 91 by the pressure of the first fuel in the first storage portion 103. Then, in the piston mechanism 48, the piston 102 moves to the communication path 93 side, and the second fuel is stored in the second storage portion 104. At this time, when the control device 105 closes (non-energizes) the solenoid valve 163 based on the detection result of the position sensor 106, a predetermined amount of the second fuel is stored in the second storage portion 104.

[0075] As shown in FIG. 11, when the solenoid valve 89 is opened (energized), in the spool valve mechanism 47A, the first fuel on the spool 82d side is discharged from the drain passage 88, and the valve body 82A moves to the drain passage 88 side. Then, in the spool valve mechanism 47A, the supply port 83 and the first supply / discharge port 85 communicate with each other, and the first fuel in the first fuel supply passage 86 flows through the spool valve 80A into the communication passage 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 to the first branch passage 73 side. At this time, the first fuel in the first storage portion 103 enters the sliding portion between the cylinder 101 and the piston 102 and functions as a lubricant. Also, the second fuel in the second storage portion 104 is prevented from entering the first storage portion 103 through the sliding portion. Then, the piston mechanism 48 supplies the second fuel in the second storage portion 104 to the fuel injection valve 33A via the first branch passage 73 and the second branch passage 74.

[0076] Further, when the valve body 82A of the spool valve mechanism 47A moves to the drain passage 88 side, the second discharge port 161 and the second supply / discharge port 162 communicate with each other. Then, in the fuel injection valve 33A, the first fuel in the control chamber 158 is discharged into the return passage 91 via the communication passage 165, the spool valve 80A, and the communication passage 164, the needle valve 151 moves upward, and the seat portion S3 is opened. At this time, the fuel injection valve 33A first injects the first fuel remaining in the second branch passage 74 and the chamber 154 from the nozzle 153. Subsequently, the fuel injection valve 33A injects the second fuel supplied from the piston mechanism 48 from the nozzle 153.

[0077] When the piston mechanism 48 moves the piston 102 by a predetermined amount toward the second reservoir 104, the first reservoir 103 communicates with the first fuel injection path 166. Then, the first fuel supplied from the first fuel supply path 86 through the spool valve 80A and the communication path 93 to the first reservoir 103 of the piston mechanism 48 is supplied to the fuel injection valve 33A through the second branch path 74 of the second fuel supply path 44. Here, the fuel injection valve 33A injects the first fuel instead of the second fuel. Then, when the solenoid valve 89 is closed (de-energized), the spool valve mechanism 37A moves the spool valve 80A to its original position, and the fuel injection valve 33A stops injecting the first fuel. At this time, the first fuel remains in the second branch path 74 and the chamber 154.

[0078] [Third Embodiment] FIG. 12 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 first and second embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

[0079] As shown in FIG. 12, the fuel injection device 14B is substantially the same as the fuel injection device 14A of the second embodiment, and includes a fuel supply device 31, a fuel supply path 32A, 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 path 32A has a first fuel supply path 43A and a second fuel supply path 44. The fuel injection valve 33A has a needle valve 151. The fuel injection device 14B also includes a spool valve mechanism 47A and a piston mechanism 48.

[0080] The piston mechanism 48 has a cylinder 101 and a piston 102. A communication path 93 from the spool valve mechanism 47A communicates with the first reservoir 103, and a first branch path 73 of the second fuel supply path 44 communicates with the second reservoir 104. The piston mechanism 48 also has a first fuel injection path 166 connected to the second branch path 74 of the second fuel supply path 44 communicating with an intermediate portion in the longitudinal direction of the cylinder 101.

[0081] In addition, the piston mechanism 48 is provided with a lift stopper 171 that restricts the amount of movement of the piston 102 relative to the cylinder 101. The lift stopper 171 is operable and can adjust the amount of movement of the piston 102 as necessary.

[0082] Other configurations are the same as those in the first and second embodiments, and the description thereof will be omitted.

[0083] [Advantages of the present embodiment] The fuel injection device according to the first aspect includes a first fuel supply path 43, 43A 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, fuel injection valves 33, 33A to which the first fuel supply path 43, 43A and the second fuel supply path 44 are connected, a supply port 83 for the first fuel that communicates with the first fuel supply path 43, 43A, a first discharge port 84 for the first fuel, and a spool valve mechanism 47, 47A that has a first supply / discharge port 85 that communicates with the supply port 83 or the first discharge port 84 according to the movement position of the valve bodies 82, 82A, and a piston mechanism 48 in which the second fuel supply path 44 communicates with one side in the movement direction of the piston 102 and the first supply / discharge port 85 communicates with the other side in the movement direction of the piston 102 via a communication path 93.

[0084] According to the fuel injection device according to the first aspect, by switching the communication relationship between the supply port 83, the first discharge port 84, and the first supply / discharge port 85 by the spool valve mechanism 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.

[0085] The fuel injection device according to the second aspect is the fuel injection device according to the first aspect, and further, in the spool valve mechanisms 47, 47A, a first communication path 86a from the first fuel supply path 86 communicates with one side in the moving direction of the valve bodies 82, 82A, and 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 of 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.

[0086] The fuel injection device according to the third aspect is the fuel injection device according to the first aspect or the second aspect, and further, in the spool valve mechanisms 47, 47A, a throttle 87 is provided in the second communication path 86b. Thereby, the flow rate of the first fuel discharged from the spool valves 80, 80A to the drain path 88 is restricted by the throttle 87, and the stable movement of the valve bodies 82, 82A can be maintained.

[0087] The fuel injection device according to the fourth aspect is the fuel injection device according to any one of the first aspect to the third aspect, and further, the piston mechanism 48 has a first storage portion 103 that communicates with the first fuel supply paths 43, 43A to store the first fuel, and a second storage portion 104 that communicates with the second fuel supply path 44 to store the second fuel, and the area of the first pressure receiving surface of the piston 102 facing the first storage portion 103 is smaller than the area of the second pressure receiving surface facing the second storage portion 104. Thereby, since the pressure of the first fuel in the first storage portion becomes higher than the pressure of the second fuel in the second storage portion 104, it is possible to prevent the second fuel in the second storage portion 104 from flowing to the first storage portion 103 side and mixing into the first fuel.

[0088] The fuel injection device according to the fifth aspect is the fuel injection device according to any one of the first to fourth aspects, and further, the fuel injection valve 33 includes a main body 51 provided with nozzles 52 and 53 at its tip, a first needle valve 45 movably provided inside the main body 51 and capable of communicating with the nozzle 52 via a first fuel supply passage 43 according to the moving position, and a second needle valve 46 movably provided between the main body 51 and the first needle valve 45 and capable of communicating with the nozzles 52 and 53 via a second fuel supply passage 44 according to the moving position. Thereby, the first fuel can be injected from the nozzle 52 by the movement of the first needle valve 45, and the second fuel can be injected from the nozzles 52 and 53 by the movement of the second needle valve 46.

[0089] The fuel injection device according to the sixth aspect is the fuel injection device according to the fifth aspect, 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 and 53, 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 and 53. Thereby, the first fuel and the second fuel can be selectively injected from the nozzles 52 and 53 according to the moving positions of the first needle valve 45 and the second needle valve 46.

[0090] The fuel injection device according to the seventh aspect is a fuel injection device according to any one of the first to fourth aspects, and further, the spool valve mechanism 37A has a second discharge port 161 for the first fuel and a second supply / discharge port 162 that communicates with the supply port 83 or the second discharge port 161 according to the movement position of the valve body 82A. The fuel injection valve 33A has a main body 152 provided with a nozzle 153 at its tip, and a needle valve 151 that is movably provided on the main body 152 and can open and close the nozzle 153 according to the movement position. The second supply / discharge port 162 communicates with the base end portion side of the needle valve 151. Thus, 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, discharging the first fuel of the piston mechanism 48 from the communication path 93, moving the piston 102, and storing the second fuel. Also, the supply port 83 and the second supply / discharge port 162 communicate with each other, supplying the first fuel to the base end portion of the needle valve 151 and closing the nozzle 153. 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, supplying the first fuel in the first fuel supply path 86 from the communication path 93 to the piston mechanism 48, moving the piston 102, and supplying the second fuel to the fuel injection valve 33A. At this time, the second discharge port 161 and the second supply / discharge port 162 communicate with each other, discharging the first fuel acting on the base end portion of the needle valve 151 to the return path 91, moving the needle valve 151, opening the nozzle 153, and injecting the first fuel and the second fuel.

[0091] The fuel injection device according to the eighth aspect is a fuel injection device according to any one of the fifth to seventh aspects, and further, the fuel injection valve 33A has a chamber 154 communicating with the nozzle 153 and a biasing spring 157 that biases the needle valve 151 in the direction of closing the nozzle 153. A first fuel injection path 166 is provided that communicates the other side in the moving direction of the piston 102 and the chamber 154 according to the movement position of the piston 102. Thus, after the needle valve 151 moves and the nozzle 153 is opened, and the piston 102 moves to a predetermined position, the first storage portion 103 communicates with the second fuel supply path 44 through the first fuel injection path 166, and the second fuel is supplied to the needle valve 151, so that the first fuel can be injected instead of the second fuel.

[0092] The fuel injection device according to the ninth aspect is a fuel injection device according to any one of the fifth to eighth aspects, and further, a solenoid valve (on-off valve) 163 is provided in a return path (first fuel discharge path) 91 communicating with the first discharge port 84. Thereby, by controlling the opening and closing timing of the solenoid valve 163, the piston mechanism 48 can adjust the storage amount of the second fuel stored in the second storage portion 104, that is, the injection amount of the second fuel injected by the fuel injection valve 33A at one time.

[0093] The reciprocating internal combustion engine according to the tenth aspect includes an engine body 11 having a combustion chamber 25 and a fuel injection device 14, 14A, 14B according to any one of the first to tenth aspects that injects fuel into the combustion chamber 25. Thereby, by suppressing the mixing of the first fuel and the second fuel, high-precision fuel injection can be enabled and harmful substances contained in the exhaust gas can be reduced.

Explanation of Signs

[0094] 10 Engine (reciprocating internal combustion engine) 11 Engine body (internal combustion engine body) 12 Intake path 13 Exhaust path 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 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 Room, First Control Room 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 Return 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 106 Position Sensor 151 Needle Valve 152 Body 153 Nozzle 154 Chamber 161 Second Discharge Port 162 Second Supply - Discharge Port 163 Solenoid Valve (On - Off Valve) 166 First Fuel Injection Path 171 Lift Stopper S1 First Seat Portion S2 Second Seat Portion S3 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; a spool valve mechanism having a supply port for the first fuel communicating with the first fuel supply path and a first discharge port for the first fuel, and having a first supply / discharge port communicating with the supply port or the first 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 first supply / exhaust port via a communication path; A fuel injection device comprising:

2. 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; 2. The fuel injection system of claim 1.

3. The spool valve mechanism has a restriction provided in the second communication path.

3. A fuel injection system according to claim 2.

4. the piston mechanism has a first storage portion communicating with the first fuel supply path and storing the first fuel, and a second storage portion communicating with the second fuel supply path and storing the second fuel, and the piston has a first pressure-receiving surface facing the first storage portion, the area of ​​the first pressure-receiving surface facing the second storage portion being smaller than an area of ​​a second pressure-receiving surface facing the second storage portion, 2. The fuel injection system of claim 1.

5. the fuel injection valve has a body having a nozzle at a tip thereof, a first needle valve movably provided inside the body and capable of connecting the first fuel supply path to the nozzle depending on a moving position thereof, and a second needle valve movably provided between the body and the first needle valve and capable of connecting the second fuel supply path to the nozzle depending on a moving position thereof.

2. The fuel injection system of claim 1.

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 nozzle hole, when the first needle valve is in their raised position, the first fuel supply path communicates with the nozzle hole, and when the second needle valve is in their raised position, the second fuel supply path communicates with the nozzle hole.

6. A fuel injection system according to claim 5.

7. the spool valve mechanism has a second exhaust port for the first fuel and a second supply / exhaust port communicating with the supply port or the second exhaust port depending on a moving position of a valve body, the fuel injection valve has a body having a nozzle at a tip end thereof, and a needle valve movably provided on the body and capable of opening and closing the nozzle depending on a moving position thereof, and the second supply / exhaust port communicates with a base end side of the needle valve.

2. The fuel injection system of claim 1.

8. the fuel injection valve has a chamber communicating with the nozzle hole, and a biasing member that biases the needle valve in a direction to close the nozzle hole, and a first fuel injection path is provided that connects the other side in the moving direction of the piston with the chamber depending on a moving position of the piston.

8. A fuel injection system according to claim 7.

9. an on-off valve is provided in a first fuel discharge path communicating with the first discharge port; 2. The fuel injection system of claim 1.

10. An internal combustion engine body having a combustion chamber; A fuel injection device as claimed in claim 1 for injecting fuel into the combustion chamber; A reciprocating internal combustion engine comprising:

Images