JP2010265855A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device capable of injecting two kinds of fuel with different timing. <P>SOLUTION: A first control valve 100 of this fuel injection device 10 operates a first valve element 101 so as to be positioned in a pressurizing position in the case wherein a first control pressure chamber 150 and a return fuel line R1 are communicated with each other and communication between a second control pressure chamber 160 and the return fuel line R1 is cut off and so as to be positioned in a pressure reducing position in the case wherein communication between the first control pressure chamber 150 and the return fuel line Ra is cut off and communication between the second control pressure chamber 160 and the return fuel line R1 is cut off and in the case wherein the first control pressure chamber 150 and the return fuel line R1 are communicated with each other and the second control pressure chamber 160 and the return fuel line R1 are communicated with each other. A second control valve 200 operates a second valve element 202 so as to be positioned in a pressurizing position in the case wherein communication between a control pressure chamber 240 and the return fuel line R1 is cut off and so as to be positioned in a pressure reducing position in the case wherein the control pressure chamber 240 and the return fuel line R1 are communicated with each other. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel injection device for an internal combustion engine, and more particularly to a fuel injection device capable of injecting two types of fuel at different timings.

  2. Description of the Related Art There are known fuel injection devices (injectors) for internal combustion engines that can inject two different types of fuel at different timings. For example, Patent Document 1 below discloses a fuel injection device (fuel injector) for an internal combustion engine that can inject gaseous fuel and liquid fuel into the combustion chamber of the internal combustion engine at different timings.

JP-T-2004-501306

  Incidentally, since the fuel injector described in Patent Document 1 uses two solenoid-driven valves (solenoid valves) for gaseous fuel control and pilot fuel (liquid fuel) control, the cost of the fuel injection device There is a problem that becomes high. There is a demand for a fuel injection device that can individually lift two nozzle needles and inject two types of fuel (for example, gaseous fuel and liquid fuel) at different timings without using a plurality of solenoid-driven valves. Yes.

  The present invention has been made in view of the above, and provides a fuel injection device capable of injecting two types of fuel at different timings without using a plurality of solenoid-driven valves.

  In the fuel injection device according to the present invention, the pressurization valve opening chamber communicating with the low pressure side passage is pressurized by communicating with the high pressure side passage, the first nozzle needle is lifted, and the pressure reducing chamber communicates with the high pressure side passage. A fuel injection device in which the valve opening chamber is decompressed by communicating with the low pressure side passage and the second nozzle needle is lifted, and the pressure opening valve chamber and the high pressure side passage communicate with each other. The first valve body is operated at one of a pressurizing position for pressurization and a decompression position for blocking the communication between the pressurization valve opening chamber and the high-pressure side passage and depressurizing the pressurization valve open chamber, A first control valve capable of controlling pressurization / depressurization of the pressure-opening chamber, a pressurizing position for pressurizing the decompression-opening chamber by blocking communication between the decompression-opening chamber and the low-pressure side passage, and a decompression-opening chamber The second valve body is operated at any one of a decompression position for decompressing the decompression valve opening chamber by communicating with the low pressure side passage, A second control valve capable of controlling pressurization / depressurization of the pressure-opening valve chamber, and the first control valve communicates with the high-pressure side passage and the first port is open when the first port is opened. A first control pressure chamber communicating with the low pressure side passage from the first port, and a second communication communicating with the high pressure side passage and the second port communicating with the low pressure side passage when the second port is open. A control pressure chamber; and a first piston capable of operating the first valve body in response to pressure changes in the first control pressure chamber and the second control pressure chamber, wherein the first control pressure chamber and the low pressure side passage communicate with each other. When the communication between the second control pressure chamber and the low pressure side passage is interrupted, the first valve body is in the pressurizing position, while the communication between the first control pressure chamber and the low pressure side passage is interrupted, And when the communication between the second control pressure chamber and the low pressure side passage is interrupted, the first control pressure chamber and the low pressure side passage communicate with each other, and When the second control pressure chamber and the low-pressure side passage communicate with each other, the first piston is configured to operate the first valve body to the decompression position, and the second control valve communicates with the high-pressure side passage, And when the second port is open, a control pressure chamber communicating from the second port to the low pressure side passage, and a second piston capable of operating the second valve body in response to a pressure change in the control pressure chamber, The second valve element is in the pressurizing position when the communication between the control pressure chamber and the low pressure side passage is interrupted, while the second piston is in the second position when the control pressure chamber and the low pressure side passage communicate with each other. The two-valve body is configured to be operated to a decompression position.

  In the above fuel injection device, the first port and the low-pressure side passage are communicated with a first position that blocks the communication between the first port and the low-pressure side passage and blocks the communication between the second port and the low-pressure side passage. And a third position where the second port communicates with the low pressure side passage, and a third position which communicates the first port with the low pressure side passage and blocks communication between the second port and the low pressure side passage. A three-position valve on which the valve body is operated can be further provided.

  In the fuel injection device, the first nozzle needle is a gas fuel nozzle needle in which gaseous fuel is injected from the gas fuel injection hole by lifting, and the second nozzle needle is for liquid fuel by lifting. The nozzle needle for liquid fuel from which liquid fuel is injected from the nozzle hole, the high-pressure side passage is a liquid fuel supply line that is a pipe that supplies the pressurized liquid fuel to the fuel injection device, and the low-pressure side passage is It may be a return fuel line that is a conduit that returns liquid fuel that has not been injected by the fuel injection device toward the fuel tank.

  According to the present invention, the lift / seat of the first nozzle needle and the seat / lift of the second nozzle needle are controlled only by controlling the opening / closing of the first port and the opening / closing of the second port. Each of the two nozzle needles can be controlled separately, and two types of fuel can be injected at different timings without using a plurality of solenoid-driven valves.

FIG. 1 is a cross-sectional view showing the overall configuration of the fuel injection device according to the present embodiment. FIG. 2 is an enlarged cross-sectional view showing the peripheral configuration of the nozzle needle in the fuel injection device according to the present embodiment. FIG. 3 is an enlarged cross-sectional view showing the peripheral configuration of the first control valve and the second control valve in the fuel injection device according to the present embodiment. FIG. 4 is an enlarged cross-sectional view for explaining the configuration of a three-position valve in the fuel injection device according to the present embodiment. FIG. 5 is a schematic diagram illustrating a “zero lift” state in which the valve body of the three-position valve according to the present embodiment is operated to the “first position”. FIG. 6 is a schematic diagram for explaining an “intermediate lift” state in which the valve element of the three-position valve according to the present embodiment is operated to the “second position”. FIG. 7 is a schematic diagram for explaining a “full lift” state in which the valve element of the three-position valve according to the present embodiment is operated to the “third position”.

  EMBODIMENT OF THE INVENTION Below, the form (henceforth embodiment) for implementing this invention is demonstrated with reference to drawings. The present invention is not limited to the embodiments described below.

  First, the structure of the fuel injection device according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the overall configuration of the fuel injection device according to the present embodiment. FIG. 2 is an enlarged cross-sectional view showing the peripheral configuration of the nozzle needle in the fuel injection device according to the present embodiment. FIG. 3 is an enlarged cross-sectional view showing the peripheral configuration of the first control valve and the second control valve in the fuel injection device according to the present embodiment. FIG. 4 is an enlarged cross-sectional view for explaining the configuration of a three-position valve in the fuel injection device according to the present embodiment.

  The internal combustion engine to which the fuel injection device according to the present embodiment is applied is a compression ignition type internal combustion engine, that is, a diesel engine, and the internal combustion engine is mounted on an automobile as a prime mover. The fuel injection device according to the present embodiment is provided in the internal combustion engine, and the injection hole faces the combustion chamber. The fuel injection device injects fuel into the atmosphere in the combustion chamber that has been compressed and brought to a high temperature.

  The fuel injection device 10 can inject two different types of fuel, that is, a first fuel and a second fuel, from the corresponding injection holes 11 and 12, respectively. In this embodiment, gaseous fuel is injected as the first fuel. The liquid fuel is injected as the second fuel. For example, compressed natural gas (CNG) or the like is used as the gaseous fuel, and light oil is used as the liquid fuel, for example.

  The internal combustion engine is provided with a pipeline (hereinafter referred to as a gaseous fuel supply line) G1 for supplying gaseous fuel from a gaseous fuel tank (not shown) to the fuel injection device 10. The gaseous fuel supplied to the fuel injection device 10 from the gaseous fuel supply line G1 is regulated to a predetermined pressure (for example, 20 MPa) by a pressure adjustment valve (not shown).

  In addition, the internal combustion engine has a pipe line F1 (hereinafter referred to as a liquid fuel supply line) F1 that supplies liquid fuel supplied from a liquid fuel tank and pressurized by a high-pressure fuel supply pump (not shown) to the fuel injection device 10. Is provided. The liquid fuel supplied to the fuel injection device 10 from the liquid fuel supply line F1 is adjusted to a predetermined pressure by a pressure adjustment valve (not shown). In the following description, the fuel passage through which the pressurized liquid fuel flows in the fuel injection device 10 will be referred to as a “liquid fuel passage”. The fuel pressure in the liquid fuel supply line and the liquid fuel passage is set to 180 MPa, for example.

  Further, the internal combustion engine is provided with a pipe line (hereinafter referred to as a return fuel line R1) for returning the liquid fuel that has not been injected from the liquid fuel injection hole 12 in the fuel injection device 10 toward the liquid fuel tank. Yes. In the following description, the liquid fuel tank is supplied from the liquid fuel supply line F1 to the fuel injection device 10, but is not injected from the liquid fuel injection hole 12, but from the fuel injection device 10 through the return fuel line R1. The liquid fuel returned to is particularly referred to as “return fuel”. The liquid fuel passage through which the return fuel provided in the fuel injection device 10 flows is particularly referred to as a “return fuel passage”. The pressure in the return fuel line and the return fuel passage is about atmospheric pressure.

  Thus, the liquid fuel supply line F1 is a fuel passage having a higher pressure than the return fuel line R1 (for example, about 180 MPa). In this embodiment, the “high-pressure side passage” is the liquid fuel supply line. F1 and the “low pressure side passage” is the return fuel line R1.

  The fuel injection device 10 is provided with a gas fuel injection hole 11 as a first injection hole through which gaseous fuel as a first fuel is injected, and separately from this, liquid fuel as a second fuel is injected. A liquid fuel injection hole 12 is provided as the second injection hole. The gaseous fuel injection hole 11 is provided in the first body B1 which is the body closest to the combustion chamber among the injector bodies forming the exterior of the fuel injection device 10. The injector body is formed by laminating the first body B1, the second body B2, the third body B3, the fourth body B4, the fifth body B5, the sixth body B6, the seventh body B7, and the eighth body B8. Yes. The first body B1 to the eighth body B8 are integrally coupled by a fastening member such as a bolt (not shown). The gaseous fuel injection hole 11 is formed in a portion (hereinafter referred to as a protruding portion) B1a of the first body B1 that constitutes the most combustion chamber side of the injector body and that protrudes toward the combustion chamber side.

  On the other hand, the liquid fuel injection hole 12 is formed in a gaseous fuel nozzle needle 15 as a first nozzle needle, as shown in FIG. The gaseous fuel nozzle needle 15 is a cylindrical valve body having a bottom, and is accommodated in the first body B1. The bottom 16 of the gaseous fuel nozzle needle 15 faces the combustion chamber, and the liquid fuel injection hole 12 is formed in the bottom 16. On the other hand, the liquid as the second nozzle needle that closes the liquid fuel injection hole 12 (second injection hole) formed in the bottom 16 in the radially inner space of the cylindrical portion 17 of the gaseous fuel nozzle needle 15. A fuel nozzle needle 20 is accommodated.

  The liquid fuel nozzle needle 20 is a needle-like valve body, and is coaxially disposed in the inner space on the radially inner side of the gas fuel nozzle needle 15. The axis of the liquid fuel nozzle needle 20 coincides with the axis of the gas fuel nozzle needle 15. The axes of the liquid fuel nozzle needle 20 and the gas fuel nozzle needle 15 are indicated by a one-dot chain line C in the drawing, and are simply referred to as “axis center” in the following description. As described above, of the gas fuel nozzle needle 15 and the liquid fuel nozzle needle 20, the liquid fuel nozzle needle 20 is an “inner nozzle needle” constituting the radially inner side, and the gas fuel nozzle needle 15 is It is an “outer nozzle needle” constituting the radially outer side. The liquid fuel nozzle needle 20 is lifted upward in the axial direction with respect to the bottom portion 16 of the gaseous fuel nozzle needle 15 and separated from the bottom portion 16, thereby opening (opening) the liquid fuel injection hole 12. ).

  In the following description, the direction in which the axis C of the liquid fuel nozzle needle 20 and the gas fuel nozzle needle 15 extends is simply referred to as “axial direction”. On the other hand, the direction orthogonal to the axis C is simply referred to as “radial direction”. Of the “axial direction”, the direction in which the liquid fuel nozzle needle 20 is separated from the gaseous fuel nozzle needle 15, that is, the direction in which the liquid fuel nozzle needle 20 and the gaseous fuel nozzle needle 15 are lifted is “axially upward”. Or, “Axial upward”. On the other hand, the direction in which the liquid fuel nozzle needle 20 contacts the gaseous fuel nozzle needle 15 is referred to as “downward in the axial direction” or “downward in the axial direction”.

  In addition, the gas fuel nozzle needle 15 moves axially upward with respect to the first body B1, and the liquid fuel nozzle needle 20 moves axially with respect to the bottom 16 of the gas fuel nozzle needle 15. The separation is referred to as “lift”. On the other hand, the state in which the gas fuel nozzle needle 15 and the liquid fuel nozzle needle 20 are moved downward in the axial direction and are in contact with the corresponding valve seats (valve seats) 13 and 14 is referred to as “seat”. .

  A fuel chamber (filled with liquid fuel injected from the liquid fuel injection hole 12 between the nozzle needle 15 for gas fuel and the nozzle needle 20 for liquid fuel in the radial outside of the nozzle needle 20 for liquid fuel, that is, between the nozzle needle 15 for gas fuel and the nozzle needle 20 for liquid fuel. (Hereinafter referred to as a liquid fuel chamber) 22 is provided. The liquid fuel chamber 22 communicates with the liquid fuel supply line F1 through the liquid fuel passages 21, F2, and the like, which will be described later, and receives supply of liquid fuel. When the liquid fuel nozzle needle 20 is lifted, the liquid fuel injection hole 12 communicates with the liquid fuel chamber 22 and the liquid fuel supply line F1, and the liquid fuel is injected from the liquid fuel injection hole 12 into the combustion chamber. . When the liquid fuel nozzle needle 20 is seated, the flow of the liquid fuel between the liquid fuel chamber 22 and the liquid fuel injection hole 12 is blocked, that is, “communication between the liquid fuel chamber 22 and the liquid fuel injection hole 12”. Is cut off. "

  A cylindrical gaseous fuel chamber 18 is provided between the cylindrical portion 17 of the gaseous fuel nozzle needle 15 in the radial direction, that is, between the protruding portion B1a of the first body B1 and the cylindrical portion 17 of the gaseous fuel nozzle needle 15. Is configured. The gaseous fuel chamber 18 communicates with the gaseous fuel supply line G1 via the gaseous fuel passage G2 formed in the first body B1 to the fifth body, and receives the supply of gaseous fuel from the gaseous fuel supply line G1. Yes. When the gaseous fuel nozzle needle 15 is lifted, the gaseous fuel injection hole 11 communicates with the gaseous fuel passage G2 and the gaseous fuel supply line G1 via the gaseous fuel chamber 18 to communicate with the combustion chamber from the gaseous fuel injection hole 11. Gaseous fuel is supplied. When the gaseous fuel nozzle needle 15 is seated, the communication between the gaseous fuel chamber 18 and the gaseous fuel injection hole 11 is blocked.

  An annular gas seal member 30 is provided between the gaseous fuel nozzle needle 15 and the first body B1 in order to ensure airtightness of the gaseous fuel chamber 18. On the upper side of the gas seal member 30 in the axial direction, a ring 40 is formed in the same manner as the gas seal member 30, and the ring 40, which is a member for holding the gas seal member 30, is connected to the gas fuel nozzle needle 15 and the first body B1. With a predetermined fitting gap.

  On the radially inner wall surface of the ring 40 (hereinafter referred to as the inner wall surface of the ring 40), an annular groove (hereinafter referred to as ring inner annular groove) 42 with the groove bottom facing radially inward is formed. On the radially outer wall surface, an annular groove 44 (hereinafter referred to as a ring outer annular groove) 44 whose groove bottom faces radially outward is formed. In addition, the ring 40 is provided with a through passage (hereinafter referred to as a ring through passage) 46 through which the ring inner annular groove 42 and the ring outer annular groove 44 communicate.

  On the other hand, on the radially outer wall surface of the cylindrical portion 17 of the gaseous fuel nozzle needle 15 (hereinafter referred to as the outer wall surface of the cylindrical portion 17), an annular groove ( (Hereinafter, referred to as a cylindrical portion outer annular groove) 50 is formed, and an annular groove (hereinafter, referred to as a cylindrical portion inner annular groove) 52 is also formed on the radially inner wall surface of the cylindrical portion 17. ing. In addition, the gas fuel nozzle needle 15 is provided with a penetrating passage (hereinafter referred to as a tubular portion through passage) 54 that allows the tubular portion outer annular groove 50 and the tubular portion inner annular groove 52 to communicate with each other. ing.

  On the radially outer wall surface of the liquid fuel nozzle needle 20, an annular groove (hereinafter referred to as “liquid nozzle needle annular groove”) 24 facing the tubular portion inner annular groove 52 is provided. The liquid nozzle needle annular groove 24 communicates with the liquid fuel chamber 22 via a liquid fuel passage 21 extending in the axial direction.

  In the fuel injection device 10 configured as described above, the liquid fuel from the liquid fuel supply line F1 is supplied to the liquid fuel passage F2, the ring outer annular groove 44 formed in the ring 40, the ring through passage 46, and the ring inner annular groove 42. And the cylindrical part outer annular groove 50 formed in the gaseous fuel nozzle needle 15, the cylindrical part through passage 54, the cylindrical part inner annular groove 52, the liquid nozzle needle annular groove 24, and the liquid fuel passage 21, It is supplied to the liquid fuel chamber 22. When the liquid fuel nozzle needle 20 is seated inside the gas fuel nozzle needle 15, the liquid fuel supplied from the liquid fuel supply line F 1 to the liquid fuel chamber 22 is the bottom 16 of the gas fuel nozzle needle 15. It seals in the valve seat 14 formed in this.

  Further, in the ring 40, a second ring inner annular groove 43, which is an annular groove whose groove bottom faces radially inward, is formed on the wall surface in the axial direction lower than the above-described ring through passage 46. On the radially outer wall surface, a second ring outer annular groove 45 is formed, which is an annular groove whose groove bottom faces radially outward. The second ring outer annular groove 45 communicates with the return fuel line R1 via the return fuel passages R2c and R2. In addition, the ring 40 is provided with a second ring penetration passage 47 that is a passage through which the second ring inner annular groove 43 and the ring outer annular groove 45 communicate with each other.

  The fuel injection device 10 configured as described above is configured such that, of the liquid fuel flowing from the ring inner annular groove 42 to the cylindrical portion outer annular groove 50, the spring is released from the gap between the inner wall surface of the ring 40 and the outer wall surface of the cylindrical portion 17. The liquid fuel leaking into the chamber 75 is returned from the return fuel passage R2 to the return fuel line R1, and leaks into the second ring inner annular groove 43 from the gap between the inner wall surface of the ring 40 and the outer wall surface of the cylindrical portion 17. The liquid fuel is returned to the return fuel line R1 from the second ring through passage 47, the second ring outer annular groove 45, and the return fuel passages R2c and R2.

  A piston 62 (hereinafter referred to as a pressurizing valve opening piston) 62 is coupled to the upper side in the axial direction of the nozzle needle 15 for gaseous fuel and driven in the axially upper direction under the pressure of a “pressurizing valve opening chamber” to be described later. ing. The pressurization valve-opening piston 62 has a substantially cylindrical shape surrounding the radially outer wall surface of the liquid fuel nozzle needle 20 and is accommodated in the second body B2 adjacent to the upper side in the axial direction of the first body B1. . The axially upper portion 63 of the pressurizing valve-opening piston 62 is configured to have a larger outer diameter than the other portions, and is hereinafter referred to as a “large diameter portion” 63. A “small diameter portion” 64 having a smaller outer diameter than the large diameter portion 63 is provided on the lower side in the axial direction of the large diameter portion 63.

  On the lower side in the axial direction of the large-diameter portion 63 of the pressurizing valve-opening piston 62 and on the outer side in the radial direction of the small-diameter portion 64, the pressurization-opening piston 62 moves upward in the axial direction between the second body B2. As a result, a space (hereinafter referred to as a pressurization valve opening chamber) 60 whose volume increases is formed. When the pressurization valve opening chamber 60 is pressurized, an axially upward force acts on the pressurization valve opening piston 62, and the gaseous fuel nozzle needle 15 is lifted together with the pressurization valve opening piston 62. The pressurization valve opening piston 62 is radially outside the small diameter portion 64 and constitutes the axially lower side of the large diameter portion 63, and the surface of the large diameter portion 63 facing the pressurization valve opening chamber 60. Thus, it is driven upward in the axial direction under the pressure of the pressurizing valve opening chamber 60. The pressurizing valve opening chamber 60 is always in communication with the return fuel line R1 via the control pressure passage C2 and the return fuel passages R4, R3, R2. The pressure in the pressurizing valve opening chamber 60, that is, pressurization / depressurization of the pressurization valve opening chamber 60 is controlled by a first control valve 100 described later.

  A flange (hereinafter referred to as a lower end flange) 66 is provided at the axially lower end of the pressurization valve opening piston 62, and the axial direction of the gaseous fuel nozzle needle 15 is opposed to the lower end flange 66. A flange (hereinafter referred to as an upper end flange) 68 is also provided at the upper end. The lower end flange 66 of the pressurizing valve opening piston 62 and the upper end flange 68 of the gaseous fuel nozzle needle 15 are coupled by a stopper 70 that sandwiches these flanges from both sides in the axial direction. Thereby, the pressurization valve opening piston 62 and the nozzle needle 15 for gaseous fuel operate | move integrally in an axial direction.

  In addition, between the stopper 70 and the wall surface of the second body B2 that is axially above the stopper 70, the pressurized valve-opening piston 62 and the gas fuel nozzle needle 15 are disposed axially below the stopper 70. A coil spring 74 is provided for biasing to the side.

  On the upper side in the axial direction of the liquid fuel nozzle needle 20, an automatic centering ring 80, which is an annular member centered on the axis C, is provided in contact with the lower end surface of the third body B3 in the axial direction. . The automatic alignment ring 80 is configured such that the lower end surface in the axial direction is positioned on the lower side in the axial direction as it goes radially inward. Further, an automatic alignment pipe 84 which is a cylindrical member extending in the axial direction about the axis C is provided adjacent to the automatic alignment ring 80. The automatic alignment pipe 84 supports the axially upper end 20e of the liquid fuel nozzle needle 20 inserted into the internal space.

  The liquid fuel nozzle needle 20 has a protruding portion 20 c that protrudes radially outward between the self-aligning pipe 84 and the pressurization valve-opening piston 62. Between the protrusion 20c and the automatic alignment pipe 84, the liquid fuel nozzle needle 20 is urged downward in the axial direction, and the automatic alignment pipe 84 and the automatic alignment ring 80 are attached upward in the axial direction. An energizing coil spring 86 is provided. A spring chamber 88, which is a space in which the coil spring is accommodated, communicates with the return fuel line R1 via return fuel passages R2a and R2, and is filled with return fuel.

  Between the axially lower end surface of the third body B3 and the axially upper end surface of the liquid fuel nozzle needle 20, there is a liquid on the radially inner side of the automatic alignment pipe 84 and the automatic alignment ring 80. An internal space (hereinafter referred to as a decompression valve opening chamber) 90 whose volume decreases as the fuel nozzle needle 20 is displaced upward in the axial direction is formed. When the decompression valve opening chamber 90 is depressurized to a predetermined pressure, the liquid fuel nozzle needle 20 is lifted to the upper side in the axial direction by an axially upward force. The decompression valve opening chamber 90 is always in communication with the liquid fuel supply line F1 via the liquid fuel passages F4 and F5, and is filled with liquid fuel. The pressure of the decompression valve opening chamber 90, that is, pressurization / decompression of the decompression valve opening chamber 90 is controlled by a second control valve 200 described later.

  In the fuel injection device 10 configured as described above, when the pressure reducing valve opening chamber is pressurized due to the pressure of the liquid fuel supply line F1, a downward force in the axial direction is applied to the liquid fuel nozzle needle 20. As a result, the resultant force of the fuel pressure in the decompression valve opening chamber 90 (oil pressure) and the biasing force of the coil spring 86 is acting, and the upward force in the axial direction is the force due to the fuel pressure in the liquid fuel chamber 22. (Oil pressure) is acting, and the nozzle needle 20 for liquid fuel is seated. From this state, when the decompression valve opening chamber 90 communicates with the return fuel line R1 and is decompressed, the axial upward force acting on the liquid fuel nozzle needle 20 exceeds the axial downward force, and the liquid fuel The nozzle needle 20 is lifted.

  Further, in the fuel injection device 10, when the communication with the return fuel line R1 and the communication with the liquid fuel supply line F1 are blocked and the pressurized valve opening chamber is depressurized, the gas fuel nozzle needle 15 includes: As a downward force in the axial direction, a force due to the pressure of the decompression valve opening chamber 90 and a biasing force of the coil spring 86 act through the nozzle needle 20 for liquid fuel, and in addition, a coil accommodated in the spring chamber 75 The biasing force of the spring 74 acts via the stopper 70. On the other hand, the force due to the pressure in the gaseous fuel chamber 18 and the force due to the pressure in the pressurizing valve opening chamber 60 act as the upward force in the axial direction, and the nozzle needle 15 for the gaseous fuel is seated. From this state, when the pressurized valve-opening chamber 60 communicates with the liquid fuel supply line F1 and is pressurized by receiving the pressure of the liquid fuel supply line F1, the axial direction acting on the gas fuel nozzle needle 15 is applied. The upward force exceeds the downward force in the axial direction, and the gaseous fuel nozzle needle 15 is lifted.

  The third body B3 and the fourth body B4 are provided with a control valve (hereinafter referred to as a first control valve) 100 for a pressurization valve opening chamber that controls pressurization / depressurization of the pressurization valve opening chamber 60. Yes. The first control valve 100 is a three-port valve (so-called three-way valve) that switches a communication port among the three ports (fuel chambers), and has a spherical valve body (hereinafter referred to as a first valve body 101). Have the following) These three ports, that is, the fuel chambers, are always in communication with the return fuel line R1, and are always in communication with the low pressure chamber 104 whose pressure is substantially the same as the pressure of the return fuel line R1, and the liquid fuel supply line F1. There is a high-pressure chamber 108 whose pressure is substantially the same as that of the liquid fuel supply line F1, and a control chamber 106 which is always in communication with the pressurization valve-opening chamber 60 and whose pressure changes according to the position of the first valve body. In the first control valve 100, the control valve 106 and the high pressure chamber 108 communicate with each other when the first valve body 101 moves to the low pressure chamber 104 side (the upper side in the axial direction). On the other hand, the control valve 106 and the low pressure chamber 104 communicate with each other when the first valve body 101 moves to the high pressure chamber 108 side (downward in the axial direction).

  The first control valve 100 is biased to a “pressurizing position” where the control chamber 106 and the high pressure chamber 108 are communicated with each other and the control chamber 106 and the low pressure chamber 104 are not communicated with each other. Therefore, a piston (hereinafter referred to as an urging piston) 110 that abuts on the first valve body 101 and a coil spring 112 that urges the first valve body 101 and the urging piston 110 toward the low pressure chamber 104 are provided. It has been. The biasing piston 110 and the coil spring 112 are accommodated in a spring chamber 114 provided between the liquid fuel passage F3 and the high-pressure chamber 108. The energizing piston 110 is provided with a liquid fuel passage 111 that allows the high-pressure chamber 108 and the spring chamber 112 to communicate with each other.

  Further, the first valve body 101 is operated to the “decompression position” where the control chamber 106 and the low pressure chamber 104 are communicated with the first control valve 100 and the control chamber 106 and the high pressure chamber 108 are not communicated. For this purpose, a piston (hereinafter referred to as a first piston) 120 that contacts and operates the first valve body 101 is provided. The first piston 120 extends in the low-pressure chamber 104, a tip portion 121 whose tip abuts against the first valve body 101, a small diameter portion 122 whose outer diameter is set larger than the tip portion 121, The large-diameter portion 124 is set to have a larger outer diameter than the small-diameter portion 122.

  In the first control valve 100, the high pressure chamber 108 communicates with the liquid fuel supply line F1 via the spring chamber 114 and the liquid fuel passages F3 and F2. The low pressure chamber 104 communicates with the return fuel line R1 through return fuel passages R3 and R2. The control chamber 106 communicates with the pressurization valve opening chamber 60 via the control pressure passages C1 and C2. The control pressure passages C1 and C2 are also communicated with the return fuel line R1 via return fuel passages R4, R3, and R2. In the middle of the control pressure passages C1 and C2 that connect the control chamber 106 and the pressurization valve opening chamber 60, there is provided a “throttle” S1 that reduces the cross-sectional area of the flow path and gives flow resistance to the flow of liquid fuel. It has been. A similar throttle S2 is also provided in the middle of the return fuel passage R4 that connects the junction 116 between the control pressure passage C1 and the control pressure passage C2 and the return fuel passage R3.

  In the first control valve 100, the first valve body 101 is biased by the resultant force of the biasing force of the coil spring 112 and the force of the fuel pressure in the spring chamber 114, and the “low pressure side” is the valve seat on the low pressure chamber 104 side. The control chamber 106 and the high-pressure chamber 108 communicate with each other by being operated to a position where the sheet “130” abuts. When the control chamber 106 and the high pressure chamber 108 communicate with each other, the pressurization valve opening chamber 60 communicates with the liquid fuel supply line F1 and also with the return fuel line R1. The fuel from the liquid fuel supply line F <b> 1 flows into the pressurization valve opening chamber 60 through the high pressure chamber 108 and the control chamber 106. At this time, since the “throttle” S2 is provided between the pressurizing valve opening chamber 60 and the return fuel passage R4, the pressurization valve opening chamber 60 is pressurized by that amount. .

  In this way, the position where the first valve body 101 contacts the low pressure side seat 130 and the control chamber 106 and the high pressure chamber 108 communicate with each other, that is, the pressurization valve opening chamber 60 and the liquid fuel supply line F1 which is the high pressure side passage. By operating to the position to be communicated, the pressurization valve opening chamber 60 is constantly pressurized but is in communication with the return fuel line R1. This valve body position becomes the “pressurizing position” in the first control valve 100. In the first control valve 100, the first valve body is in a “pressurization position” where the pressurized valve opening chamber 60 is pressurized by communicating the pressurized valve opening chamber 60 with the liquid fuel supply line F1, which is a high-pressure side passage. By operating 101, the gaseous fuel nozzle needle 15 that has been seated on the injector body up to that point is lifted.

  On the other hand, in the first control valve 100, the first piston 120 moves the first valve body 101 against the resultant force of the biasing force of the coil spring 112 and the force (oil pressure) generated by the fuel pressure of the spring chamber 114. The control chamber 106 and the low pressure chamber 104 communicate with each other by operating the first valve body 101 to a position where it abuts against a valve seat (hereinafter referred to as a high pressure side seat) 132 on the high pressure chamber 108 side. When the control chamber 106 and the low-pressure chamber 104 communicate with each other, the pressurization valve-opening chamber 60 is disconnected from the liquid fuel supply line F1 and is decompressed by communicating with the return fuel line R1.

  Thus, the position where the first valve body 101 contacts the high-pressure side seat 132 and the control chamber 106 and the low-pressure chamber 104 communicate with each other, that is, the position where the communication between the pressurized valve-opening chamber 60 and the liquid fuel supply line F1 is blocked. As a result, the pressurized valve-opening chamber 60 that is always in communication with the return fuel line R1 is decompressed. This valve body position becomes the “decompression position” in the first control valve 100. In other words, in the first control valve 100, the first piston 120 shuts off the communication between the pressurized valve-opening chamber 60 and the liquid fuel supply line F1, and is moved to the “decompression position” where the pressurized valve-opening chamber 60 is depressurized. By operating the one-valve body 101, the gaseous fuel nozzle needle 15 is seated on the injector body. In addition, the structure for operating the 1st valve body 101 in the 1st control valve 100 is mentioned later.

  On the other hand, the third body B3 and the fourth body B4 are provided with a control valve (hereinafter referred to as a second control valve) 200 for a decompression valve opening chamber that controls pressurization / decompression of the decompression valve opening chamber 90. Yes. The second control valve 200 is a three-port valve (three-way valve) that switches a port to be communicated among three ports (fuel chambers), and is a spherical valve body (hereinafter referred to as a second valve body). ) 202. The three ports, that is, the fuel chambers, are always in communication with the return fuel line R1, and the pressure is approximately the same as the pressure of the return fuel line R1, and the liquid fuel supply line F1. There is a control chamber 206 that is always in communication with the high-pressure chamber 208 whose pressure is substantially the same as the pressure of the liquid fuel line, and the decompression valve-opening chamber 90, and the pressure changes according to the position of the second valve body. . In the second control valve 200, the second valve body 202 moves to the low pressure chamber 204 side (the upper side in the axial direction), so that the control chamber 206 and the high pressure chamber 208 communicate with each other and the high pressure chamber 208 side (the lower side in the axial direction). As the second valve body 202 moves, the control chamber 206 and the low pressure chamber 204 communicate with each other.

  In order to urge the second valve body 202 to a position where the control chamber 206 and the high pressure chamber 208 are communicated with the second control valve 200 and the control chamber 206 and the low pressure chamber 204 are not communicated with each other, A piston (hereinafter referred to as an urging piston) 210 that contacts the valve body 202 and a coil spring 212 that urges the second valve body 202 and the urging piston 210 toward the low pressure chamber 204 are provided. The biasing piston 210 and the coil spring 212 are accommodated in a spring chamber 214 provided between the liquid fuel passages F4 and F5 and the high pressure chamber 208. The biasing piston 210 is provided with a liquid fuel passage 211 that allows the high-pressure chamber 208 and the spring chamber 214 to communicate with each other.

  In addition, the second control valve 200 is configured to operate the second valve body 202 at a position where the control chamber 206 and the low pressure chamber 204 are communicated with each other and the control chamber 206 and the high pressure chamber 208 are not communicated with each other. An operation piston (hereinafter referred to as a second piston) 220 is provided in contact with the two-valve body 202 to operate it. The second piston 220 extends in the low-pressure chamber 204 described above, and has a tip 221 whose tip abuts against the second valve body 202 and a small-diameter portion 222 whose outer diameter is set larger than that of the tip 221. And a large-diameter portion 224 whose outer diameter is set larger than that of the small-diameter portion 222.

  In the second control valve 200, the high pressure chamber 208 communicates with the liquid fuel supply line F1 via the spring chamber 214 and the liquid fuel passage, and the decompression valve opening chamber 90 via the spring chamber 214 and the liquid fuel passage F4. Communicated with. A throttle S4 is provided in the middle of the liquid fuel passage F4 that allows the spring chamber 214 and the decompression valve opening chamber 90 to communicate with each other. The control chamber 206 communicates with the decompression valve opening chamber 90 via the control pressure passage C3. A throttle S3 is provided in the middle of the control pressure passage C3 that allows the control chamber 206 and the decompression valve opening chamber 90 to communicate with each other. The low pressure chamber 204 communicates with the return fuel line R1 via return fuel passages R3 and R2.

  In the second control valve 200, the second valve body 202 is biased by the resultant force of the biasing force of the coil spring 212 and the force (oil pressure) due to the fuel pressure of the spring chamber 214, and the valve seat on the low pressure chamber 204 side. By being operated to a position where the “low pressure side seat” 230 is in contact, the communication between the control chamber 206 and the low pressure chamber 204 is blocked. When the communication between the control chamber 206 and the low pressure chamber 204 is interrupted, the decompression valve opening chamber 90 communicating with the liquid fuel supply line F1 is pressurized under the pressure of the liquid fuel supply line F1.

  Thus, the position where the second valve body 202 abuts on the low pressure side seat 230 and the communication between the control chamber 206 and the low pressure chamber 204 is cut off, that is, the communication between the pressure reducing valve opening chamber 90 and the return fuel line R1 is cut off. By operating to the position to be performed, the decompression valve opening chamber 90 is pressurized by receiving the pressure of the liquid fuel supply line F1. This valve body position becomes the “pressurizing position” in the second control valve 200. In the second control valve 200, the decompression valve opening chamber 90 and the liquid fuel supply line F1 are communicated with each other, and the communication between the decompression valve opening chamber 90 and the return fuel line R1 is interrupted to pressurize the decompression valve opening chamber 90. When the second valve body 202 is operated at the “pressurizing position”, the liquid fuel nozzle needle 20 is seated.

  On the other hand, in the second control valve 200, the second piston 220 causes the second valve body 202 to move against the resultant force of the biasing force of the coil spring 212 and the force (oil pressure) due to the fuel pressure of the spring chamber 214. The control chamber 206 and the low pressure chamber 204 communicate with each other by operating the second valve body 202 to a position in contact with a valve seat (hereinafter referred to as a high pressure side seat) 232 on the high pressure chamber 208 side. When the control chamber 206 and the low pressure chamber 204 communicate with each other, the decompression valve opening chamber 90 that is always in communication with the liquid fuel supply line F1 also communicates with the return fuel line R1. The liquid fuel that has flowed from the liquid fuel supply line F1 into the decompression valve opening chamber 90 through the throttle S4 in the liquid fuel passage F4 passes from the control chamber 206 to the low pressure chamber 204 through the throttle S3 provided in the control pressure passage C3. The fuel flows out and flows through the return fuel passages R3 and R2 to the return fuel line R1. As a result, the pressure in the decompression valve opening chamber 90 is reduced compared to the pressure in the liquid fuel supply line F1.

  In this way, the second valve body 202 is in contact with the high pressure side seat 232 and communicates with the control chamber 206 and the low pressure chamber 204, that is, the pressure reducing valve opening chamber 90 and the return fuel line R1 that is the low pressure side passage. By operating at the position to be operated, the decompression valve opening chamber 90 that is always in communication with the liquid fuel supply line F1 is decompressed. This valve body position becomes the “decompression position” in the second control valve 200. In other words, in the second control valve 200, the second piston 220 connects the decompression valve opening chamber 90 and the return fuel passage to place the second valve body 202 in a "decompression position" where the decompression valve opening chamber 90 is decompressed. By operating, the liquid fuel nozzle needle 20 is lifted from the valve seat. In addition, the structure for operating the 2nd valve body 202 in the 2nd control valve 200 is mentioned later.

  The fuel injection device 10 configured as described above operates the second piston 220 that operates the position of the second valve body 202 of the second control valve 200 and the position of the first valve body 101 of the first control valve 100. In order to drive the first piston 120 separately, the valve body positions are a first position P1, a second position P2, a third position P3, and a three-way switching valve “three-position valve (three position valve) "300. The three-position valve 300 is connected to the first port A and the second port B and the return fuel line R1. The three-position valve 300 is configured to be able to separately switch between communication and blocking between the second port B and the return fuel line R1, and communication and blocking between the first port A and the return fuel line R1.

  In the following description, in the three-position valve 300, the position of the valve body that cuts off the communication between the first port A and the return fuel line R1 and cuts off the communication between the second port B and the return fuel line R1. The first position “P1” is described, and the position of the valve body that connects the first port A and the return fuel line R1 and the second port B and the return fuel line R1 is referred to as “second position” P2. The position of the valve element that connects the first port A and the return fuel line R1 and blocks the communication between the second port B and the return fuel line R1 is referred to as a “third position” P3. A detailed configuration of the three-position valve 300 according to the present embodiment will be described later.

  Next, the structure for operating the 1st valve body 101 in the 1st control valve 100 is demonstrated using FIG.

  The fourth body B4 is always in communication with the liquid fuel supply line F1 on the axially upper side of the large-diameter portion 124 of the first piston 120 (that is, the side opposite to the side where the first valve body 101 is provided). In addition, a fuel chamber (hereinafter referred to as a first control pressure chamber) 150 that can communicate with the return fuel line R1 from the first port A via the three-position valve 300 is provided. The first control pressure chamber 150 is depressurized by communicating with the return fuel line R1, and is pressurized by blocking communication with the return fuel line R1. Pressurization / decompression of the first control pressure chamber 150 is controlled according to the position of the valve body 303 (see FIG. 4) of the three-position valve 300.

  The first control pressure chamber 150 faces an “upper end face” 128 that is an end face on the upper side in the axial direction of the large diameter portion 124 of the first piston 120. The first control pressure chamber 150 communicates with the liquid fuel supply line F1 via the liquid fuel passages F6 and F7. A throttle 151 is provided in the middle of the liquid fuel passage F6 that allows the liquid fuel supply line F1 and the first control pressure chamber 150 to communicate with each other. In addition, the first control pressure chamber 150 communicates with the first port A via the control pressure passage C5. A throttle 152 is similarly provided in the control pressure passage C5 that allows the first port A and the first control pressure chamber 150 to communicate with each other.

  When the valve body of the three-position valve 300 is controlled to the first position P1 and the communication between the first port A and the return fuel line R1 is cut off, it flows into the first control pressure chamber 150 from the liquid fuel supply line F1. The liquid fuel does not flow from the first control pressure chamber 150. The first control pressure chamber 150 is pressurized by receiving substantially the same pressure as the liquid fuel supply line F1.

  On the other hand, when the valve body of the three-position valve 300 is controlled to the second position P2 or the third position P3 to connect the first port A and the return fuel line R1, the liquid fuel supply line F1 passes through the throttle 151. The liquid fuel flowing into the first control pressure chamber 150 passes through the throttle 152 of the control pressure passage C5 and is discharged from the first port A to the return fuel line R1. As a result, the first control pressure chamber 150 is depressurized compared to the pressure in the liquid fuel supply line F1.

  Further, in the first control valve 100, the fourth body B4 is located on the lower side in the axial direction of the large-diameter portion 124 of the first piston 120 (that is, the side on which the first valve body 101 is provided) and the small-diameter portion 122. The fuel chamber (hereinafter referred to as a second control pressure chamber) that is always in communication with the liquid fuel supply line F1 from the second port B and that can communicate with the return fuel line R1 through the three-position valve 300. 160) is provided. The pressure is reduced by communicating with the second control pressure chamber 160 and the return fuel line R1, and the pressure is increased by disconnecting the communication with the return fuel line R1. The pressurization / decompression of the second control pressure chamber 160 is controlled according to the position of the valve body of the three-position valve 300.

  The second control pressure chamber 160 is formed in an annular shape centering on the axis of the small diameter portion 122 of the first piston 120. The second control pressure chamber 160 communicates with the liquid fuel supply line F1 through the liquid fuel passages F8, F7, F2. A throttle 161 is provided in the middle of the liquid fuel passage F8 that allows the liquid fuel supply line F1 and the second control pressure chamber 160 to communicate with each other. In addition, the second control pressure chamber 160 communicates with the second port B via the control pressure passage C6. Similarly, a throttle 162 is provided in the control pressure passage C6 that allows the second control pressure chamber 160 and the second port B to communicate with each other.

  When the valve body of the three-position valve 300 is controlled to the first position P1 or the third position P3 and the communication between the second port B and the return fuel line R1 is cut off, the second control pressure is supplied from the liquid fuel supply line F1. The liquid fuel that has flowed into the chamber 160 does not flow from the second control pressure chamber 160. The second control pressure chamber 160 is pressurized by receiving substantially the same pressure as the liquid fuel supply line F1.

  On the other hand, when the valve body of the three-position valve 300 is controlled to the second position P2 and the second port B communicates with the return fuel line R1, the liquid fuel supply line F1 passes through the throttle 161 and enters the second control pressure chamber 160. The inflowing liquid fuel passes through the restriction 162 of the control pressure passage C6 and is discharged from the second port B to the return fuel line R1. As a result, the second control pressure chamber 160 is depressurized compared to the pressure in the liquid fuel supply line F1.

  Further, in the fifth body B5 and the fourth body B4, pistons (hereinafter referred to as pressurization) that push the first piston 120 in a direction (a lower side in the axial direction) in which the first valve body 101 of the first control valve 100 is in the pressure reducing position. 140 (referred to as a piston) is provided in contact with the upper end surface 128 of the large-diameter portion 124 of the first piston 120. The axis of the pressurizing piston 140 coincides with that of the first piston 120, and is configured in a substantially cylindrical shape. The axially lower end of the pressurizing piston 140 is in contact with the upper end surface 128 of the large diameter portion 124 of the first piston 120. In the fifth body B5, on the upper side in the axial direction of the pressurizing piston 140 (in the direction in which the first valve body 101 is in the pressurizing position), the liquid fuel supply line F1 is provided on the end surface 144 in the upper axial direction of the pressurizing piston 140. A fuel chamber (hereinafter referred to as a pressurizing chamber) 170 for applying the above pressure is formed. A liquid fuel supply line F1 communicates with the pressurizing chamber 170 via a liquid fuel passage F7, and substantially the same pressure as the liquid fuel supply line F1 is always applied.

  The cross-sectional area of the cross section perpendicular to the axial direction of the pressurizing piston 140 and the pressurizing chamber 170 (the operation direction of the first valve body 101) is set to be substantially the same as the cross-sectional area of the small diameter portion of the first piston 120. Yes. In addition, a coil spring 177 is provided in the pressurizing chamber 170 to abut against the axially upper end surface 144 of the pressurizing piston 140 and urge the pressurizing piston 140 downward in the axial direction. The axially upper end of the coil spring 177 is in contact with the wall surface defining the pressurizing chamber 170 of the fifth body B5, and the axially lower end is in contact with the axially upper end surface of the pressurizing piston 140. It touches.

  Next, the structure for operating the 2nd valve body 202 of the 2nd control valve 200 is demonstrated using FIG.

  On the lower side in the axial direction of the large-diameter portion 224 of the second piston 220 in the fourth body B4 (that is, the side where the second valve body 202 is provided), A fuel chamber (hereinafter referred to as a control pressure chamber) 240 that communicates with the liquid fuel supply line F1 and that can communicate with the return fuel line R1 from the second port B via the three-position valve 300 is provided. The control pressure chamber 240 is depressurized by communicating with the return fuel line R1, and is pressurized by blocking communication with the return fuel line R1. Pressurization / decompression of the control pressure chamber 240 is controlled according to the position of the valve body of the three-position valve 300.

  The control pressure chamber 240 is formed in an annular shape centering on the axis of the small diameter portion 222 of the second piston 220. The control pressure chamber 240 communicates with the liquid fuel supply line F1 via the liquid fuel passages F9 and F5. A throttle 241 is provided in the middle of the liquid fuel passage F9 that connects the control pressure chamber 240 and the liquid fuel supply line F1. In addition, the control pressure chamber 240 communicates with the second port B via the control pressure passages C7 and C6. Similarly, a throttle 242 is provided in the control pressure passage C7 that allows the control pressure chamber 240 and the second port B to communicate with each other.

  When the valve body of the three-position valve 300 is controlled to the first position P1 or the third position P3 and the communication between the second port B and the return fuel line R1 is cut off, the control pressure chamber 240 is controlled from the liquid fuel supply line F1. The liquid fuel that has flowed into the flow does not flow from the control pressure chamber 240. The control pressure chamber 240 is pressurized by receiving substantially the same pressure as that of the liquid fuel supply line F1.

  On the other hand, when the valve body of the three-position valve 300 is controlled to the second position P2 and the second port B communicates with the return fuel line R1, the liquid fuel supply line F1 flows into the control pressure chamber 240 through the throttle 241. The liquid fuel passes through the throttle 242 of the control pressure passage C7 and is discharged from the second port B to the return fuel line R1. Thereby, the control pressure chamber 240 is depressurized compared with the pressure of the liquid fuel supply line F1.

  In addition, on the upper side in the axial direction of the large-diameter portion 224 of the second piston 220 in the fourth body B4 (that is, the side opposite to the side where the second valve body 202 is provided), the liquid fuel supply line F1 is always provided. A fuel chamber (hereinafter referred to as a pressurizing chamber) 270 that is in communication and receives substantially the same pressure as the liquid fuel supply line F1 is provided. The pressurizing chamber 270 faces an end surface (hereinafter referred to as an upper end surface) 228 in the axial direction of the large diameter portion 224 of the second piston 220. The pressurizing chamber 270 communicates with the liquid fuel supply line F1 via the liquid fuel passages F10 and F5, and substantially the same pressure as the liquid fuel supply line F1 acts.

  Next, a configuration example of the three-position valve 300 according to the present embodiment will be described with reference to FIGS. FIG. 4 is an enlarged cross-sectional view illustrating the configuration of the three-position valve 300 in the fuel injection device 10 according to the present embodiment. FIG. 5 is a schematic diagram illustrating a “zero lift” state in which the valve body of the three-position valve 300 according to the present embodiment is operated to the “first position”. FIG. 6 is a schematic diagram for explaining the “intermediate lift” state in which the valve body of the three-position valve 300 according to the present embodiment is operated to the “second position”. FIG. 7 is a schematic diagram for explaining a “full lift” state in which the valve body of the three-position valve 300 according to the present embodiment is operated to the “third position”.

  As shown in FIG. 4, the three-position valve 300 has a substantially cylindrical valve body 303, and the valve body 303 is accommodated in the sixth body B6. A tapered and annular valve seat 306 with which the valve body 303 of the three-position valve 300 abuts (sits) is formed in the fuel chamber that houses the valve body 303. The three-position valve 300 is configured as a so-called balance-type three-port valve, and switches between two fuel chambers communicating between the three fuel chambers (ports). The three fuel chambers are a first control chamber 311 that communicates with a first port A described later, a second control chamber 312 that communicates with the second port B, and a return fuel chamber 320 that communicates with the return fuel line R1. A configuration for driving the valve body 303 of the three-position valve 300 in the fuel injection device 10 will be described later.

  In the following description, the direction in which the axial center of the valve element 303 of the three-position valve 300 extends, that is, the movement direction of the valve element 303 is referred to as “valve element movement direction”. The direction in which the valve body 303 abuts on the valve seat 306 formed on the sixth body B6 in the valve body movement direction is referred to as “lower side”. On the other hand, the direction away from the valve seat 306 formed in the sixth body B6 in the valve body moving direction is referred to as “upper side”.

  A seventh body B7 that houses a small-diameter piston 340 and a return fuel chamber 320, which will be described later, is provided adjacent to the sixth body B6 on the upper side in the valve body movement direction of the sixth body B6. In addition, an eighth body B8 that accommodates a large-diameter piston 350 and a piezo stack 360, which will be described later, is provided above the seventh body B7 in the valve body movement direction. The sixth body B6, the seventh body B7, and the eighth body B8 are integrally coupled by a fastening member such as a bolt (not shown).

  The sixth body B6 communicates with the first port A via the control pressure passage C8 above the valve seat 306 in the valve body moving direction when the valve body 303 of the three-position valve 300 is seated on the valve seat 306. A “first control chamber” 311 that is an annular fuel chamber is provided. On the other hand, a “second control chamber” 312 which is an annular fuel chamber communicating with the second port B via the control pressure passage C9 is provided below the valve seat movement direction from the valve seat 306. When the valve element 303 of the three-position valve 300 is seated, the communication between the first control chamber 311 and the second control chamber 312 is blocked. On the other hand, when the valve element 303 of the three-position valve 300 is lifted, the first control chamber 311 and the second control chamber 312 communicate with each other, that is, the first port A and the second port B communicate with each other.

  Of the valve body 303 of the three-position valve 300, an end face (hereinafter referred to as the valve body upper end face) 304 on the upper side in the valve body movement direction protrudes in an annular shape centering on the axis of the valve body on the upper side in the valve body movement direction. A portion (hereinafter referred to as an annular protrusion) 305 is provided. When the valve body 303 of the three-position valve 300 is lifted, the annular projecting portion 305 contacts the lower end surface 310 of the seventh body B7 in the valve body movement direction. In the following description, the lower end surface in the valve body movement direction with which the annular protrusion 305 of the valve body 303 of the three-position valve 300 abuts is referred to as a “seat surface” 310.

  In the seventh body B7, a “return fuel chamber” 320, which is a fuel chamber communicating with the return fuel line R1 via the return fuel passage R5, is provided to face the valve body 303 of the three-position valve 300. Specifically, the valve body 303 of the three-position valve 300 in the valve body upper end surface 304 faces the return fuel chamber 320 at a portion radially inward from the annular protrusion 305.

  A coil spring (hereinafter referred to as a valve element urging spring) as an urging member for urging the valve element upward in the valve element movement direction below the valve element movement direction from the valve element 303 of the three-position valve 300. 330 is provided. The valve body urging spring 330 is housed in a fuel chamber (hereinafter referred to as a spring housing chamber) 333 formed in the sixth body B6 on the lower side in the valve body movement direction of the valve body 303 of the three-position valve 300. Yes. The spring accommodating chamber 333 is supplied with liquid fuel of a predetermined pressure from an intermediate pressure generating valve 400 described later.

  The valve element 303 of the three-position valve 300 is urged upward in the valve element movement direction by the valve element urging spring 330, and the annular protrusion 305 on the valve element upper end surface 304 becomes the seat surface 310 of the seventh body B 7. Abut. As a result, the first control chamber 311 and the second control chamber 312 communicate with each other, and the communication between the first control chamber 311 and the return fuel chamber 320 is blocked. The valve body 303 of the three-position valve 300 is driven downward in the valve body movement direction by a small-diameter piston 340, a large-diameter piston 350, a piezo stack 360, and the like, which will be described later, and an annular projecting portion 305 of the valve body 303. The sheet surface 310 of the seventh body B7 is separated.

  As shown in FIG. 5, the valve body 303 of the three-position valve 300 is separated from the valve seat 306 of the sixth body B6, and the annular protrusion 305 of the valve body 303 of the three-position valve 300 is the seventh body B7. When the seat is in contact with the seat surface 310, the flow of liquid fuel between the first control chamber 311 and the return fuel chamber 320 is blocked, and the first control chamber 311 and the second control chamber 312 are Communicate. That is, the first port A and the second port B of the three-position valve 300 are in communication, and the first port A and the second port B are disconnected from the return fuel line R1. In the following description, the valve body 303 of the three-position valve 300 is separated from the valve seat 306 of the sixth body B6, and the annular protrusion 305 of the valve body abuts on the seat surface 310 of the seventh body B7. This state is referred to as “zero lift”. By operating the valve body of the three-position valve 300 to “zero lift”, the position of the valve body 303 of the three-position valve 300 is cut off from the communication between the first port A and the return fuel line R1 and the second port B. The "first position" P1 that cuts off the communication with the return fuel line R1 can be set.

  As shown in FIG. 6, the valve body 303 of the three-position valve 300 is separated from the valve seat 306 of the sixth body B6, and the annular protrusion 305 of the valve body 303 of the three-position valve 300 is connected to the seventh body B7. When separated from the seat surface 310, the first control chamber 311 and the second control chamber 312 communicate with each other, and the first control chamber 311 and the return fuel chamber 320 communicate with each other. That is, the first port A and the second port B of the three-position valve 300 communicate with each other, and the first port A and the second port B communicate with the return fuel line R1. In the following description, the valve element 303 of the three-position valve 300 is separated from the valve seat 306 of the sixth body B6, and the annular protrusion 305 of the valve element is also separated from the seat surface 310 of the seventh body B7. This state is referred to as “intermediate lift”. By operating the valve element 303 of the three-position valve 300 to “intermediate lift”, the position of the valve element 303 of the three-position valve 300 is made to communicate with the first port A and the return fuel line R1, and the second port B And the return fuel line R1 can be in a “second position” P2.

  As shown in FIG. 7, when the valve element 303 of the three-position valve 300 is seated in contact with the valve seat 306 of the sixth body B6, that is, the annular protrusion 305 of the valve element and the seventh body B7 When the seat surface 310 is separated, the first control chamber 311 and the return fuel chamber 320 communicate with each other through the space between the seat surface 310 and the annular protrusion 305 of the valve body. That is, the first port A of the three-position valve 300 communicates with the return fuel line R1. In this state, as described above, the flow of the liquid fuel between the first control chamber 311 and the second control chamber 312 is blocked. Therefore, the second port B of the three-position valve 300 is not in communication with the return fuel line R1, and is closed by the valve body 303 of the three-position valve 300. In the following description, a state in which the valve body 303 of the three-position valve 300 is seated on the valve seat 306 of the sixth body B6 and the annular protrusion 305 of the valve body is separated from the seat surface 310 is the three-position. This is referred to as “full lift” of the valve body 303 of the valve 300. By operating the valve element 303 of the three-position valve 300 to “full lift”, the position of the valve element 303 of the three-position valve 300 is made to communicate with the first port A and the return fuel line R1, and with the second port B and the return. A “third position” P3 that blocks communication with the fuel line R1 can be set.

  Next, a configuration for operating the valve body 303 of the three-position valve 300 will be described with reference to FIG. An eighth body B8 is provided adjacent to the seventh body B7 on the upper side in the valve body movement direction of the seventh body B7, and a small diameter piston 340 that drives the three-position valve 300, a large diameter piston 350, and Each part of the piezo stack 360 is accommodated in the seventh body B7 and the eighth body B8.

  The seventh body B7 is provided in contact with the valve body upper end surface 304 of the valve body 303 of the three-position valve 300, and receives a pressure that increases in accordance with the displacement of a large-diameter piston, which will be described later. A small-diameter piston 340 that is displaced downward in the direction is provided. The lower end of the small-diameter piston 340 contacts the valve body upper end surface 304 of the valve body 303 in the valve body moving direction. A “displacement expansion chamber” 345 that is a fuel chamber whose pressure increases in accordance with the displacement of the large diameter piston 350 downward in the valve body movement direction is provided above the small diameter piston 340 in the valve body movement direction. The small-diameter piston 340 has an end surface 342 on the upper side in the valve body movement direction facing the displacement expansion chamber 345, and is biased downward in the valve body movement direction under the pressure of the displacement expansion chamber 345. The displacement expansion chamber 345 is supplied with liquid fuel from an intermediate pressure chamber 410 described later via a check valve 380.

  Inside the eighth body B8, a large-diameter piston 350 capable of pressurizing the liquid fuel in the displacement expansion chamber 345 by being displaced downward in the valve body movement direction in accordance with the extension of a piezo stack 360 described later, A coil spring (hereinafter referred to as a large-diameter piston spring) 356 that is an urging member that urges the large-diameter piston 350 upward in the valve body movement direction is provided.

  In addition, a piezo stack 360 for displacing the large-diameter piston 350 downward in the valve body movement direction is provided in the eighth body B8. The piezo stack 360 is configured by laminating a plurality of piezoelectric elements, and is applied with an electronic control device (hereinafter simply referred to as “ECU”) for the fuel injection device 10, that is, the amount of charge supplied. Is controlled to extend downward in the valve body movement direction in accordance with the amount of charge. The lower end 361 of the piezo stack 360 in the valve body movement direction is provided in contact with the large diameter piston 350, and the large diameter piston 350 is arranged on the lower side in the valve body movement direction according to the extension amount of the piezo stack 360. It is displaced to.

  In addition, a fuel chamber (hereinafter referred to as a large-diameter spring accommodating chamber) 358 for accommodating a large-diameter piston spring 356 is provided inside the eighth body B8. The large-diameter spring accommodating chamber 358 is formed so as to surround the outer periphery of the large-diameter piston 350 and communicates with the return fuel line R1 via the return fuel passage R6. An O-ring 359 is provided between the outer periphery of the large-diameter piston 350 and the eighth body B8 to prevent liquid fuel in the large-diameter spring accommodating chamber 358 from entering the piezo stack 360 side. Yes.

  The displacement expansion chamber 345 is formed on a fuel chamber (hereinafter referred to as a large diameter side displacement expansion chamber) 346 formed on the eighth body B8 side, that is, on the large diameter piston 350 side, and on a seventh body B7 side, that is, on the small diameter piston 340 side. The fuel chamber (hereinafter referred to as a small-diameter side displacement expansion chamber) 344 is configured. The cross-sectional area of the cross section perpendicular to the valve body moving direction of the large diameter side displacement expansion chamber 346 (that is, the direction in which the large diameter piston 350 is displaced) is set larger than the cross sectional area of the small diameter side displacement expansion chamber 344. Hereinafter, the ratio of the cross-sectional areas of the large diameter side displacement expansion chamber 346 and the small diameter side displacement expansion chamber 344 will be referred to as “displacement expansion ratio”.

  In the three-position valve 300 configured as described above, when the piezo stack 360 is extended and the large diameter piston 350 is displaced downward in the valve body movement direction, the liquid fuel in the large diameter side displacement expansion chamber 346 is pressurized. Then, the pressure is transmitted to the small-diameter side displacement expansion chamber 344, and the force on the lower side in the valve body moving direction acts on the small-diameter piston 340. When the large-diameter piston 350 is displaced downward in the valve body movement direction, the volume of the small-diameter side displacement expansion chamber 344 increases by the amount corresponding to the decrease in the volume of the large-diameter side displacement expansion chamber 346, and the small-diameter piston 340 moves the valve body. It can be displaced downward in the direction. That is, the displacement of the small-diameter piston 340, that is, the displacement of the valve body 303 of the three-position valve 300 can be increased by the displacement enlargement ratio compared to the displacement of the large-diameter piston 350, that is, the extension amount of the piezo stack 360.

  Further, inside the sixth body B6, a pressure control valve (hereinafter referred to as an intermediate pressure generating valve) 400 that adjusts the pressure of the intermediate pressure chamber 410 that supplies the liquid fuel to the displacement expansion chamber 345 to a predetermined pressure. Is provided. The intermediate pressure generating valve 400 adjusts the pressure to be lower than the pressure of the liquid fuel supply line F1 and higher than the pressure of the return fuel line R1 (hereinafter referred to as intermediate pressure). In the present embodiment, the intermediate pressure is set to about 1 MPa, for example.

  The intermediate pressure generating valve 400 includes a substantially cylindrical valve body 404 and a coil spring 420 that biases the valve body 404 downward in the valve body movement direction. A spring chamber 422 that accommodates the coil spring 420 is formed in the sixth body B6. The spring chamber 422 communicates with the return fuel line R1 via the return fuel passage R7 and the return fuel chamber 320.

  Further, in the sixth body B6, the displacement is enlarged via a check valve 380 on the side opposite to the spring chamber 422 with respect to the valve body 404 of the intermediate pressure generating valve 400 (that is, the lower side in the valve body movement direction). An “intermediate pressure chamber” 410 that is a fuel chamber capable of supplying fuel adjusted to an intermediate pressure to the chamber 345 is formed. In the following description, a liquid fuel passage that is regulated to an intermediate pressure by the intermediate pressure generating valve 400 and communicates with the intermediate pressure chamber 410 is particularly referred to as an “intermediate pressure passage”. The intermediate pressure chamber 410 communicates with the liquid fuel supply line F1 through an intermediate pressure passage M1 and a liquid fuel passage F11 formed in the sixth body B6 and the seventh body B7.

  An intermediate pressure pin 430 is fitted between the intermediate pressure passage M1 and the liquid fuel passage F11. In the intermediate pressure chamber 410, the liquid fuel in the liquid fuel supply line F1 flows out to the intermediate pressure passage M1 through the fitting gap between the intermediate pressure passage M1 and the intermediate pressure pin 430, and is supplied to the intermediate pressure chamber 410. The

  In addition, the sixth body B6 and the seventh body B7 are formed with an intermediate pressure passage M3 that allows the above-described displacement expansion chamber 345 and the intermediate pressure chamber 410 to communicate with each other. A check that allows liquid fuel to flow only in the direction from the intermediate pressure chamber 410 toward the displacement expansion chamber 345 at the end of the intermediate pressure passage M3 that connects the displacement expansion chamber 345 and the intermediate pressure chamber 410 on the displacement expansion chamber 345 side. A valve 380 (check valve) is provided. When the pressure in the displacement expansion chamber 345 is lower than the intermediate pressure, the liquid fuel from the intermediate pressure chamber 410 is supplied to the displacement expansion chamber 345 through the check valve 380.

  In addition, the sixth body B6 has an intermediate pressure passage M4 that communicates the intermediate pressure chamber 410 with the spring accommodating chamber 333 formed on the lower side in the valve body movement direction of the valve body 303 of the three-position valve 300 described above. Is formed. The spring accommodating chamber 333 receives the supply of liquid fuel adjusted to an intermediate pressure. In response to the intermediate pressure in the spring accommodating chamber 333, an upward force in the valve body moving direction acts on the valve body 303 of the three-position valve 300.

  The valve body 404 of the intermediate pressure generating valve 400 protrudes radially outward of the valve body 404 on the spring chamber 422 side (that is, the upper side in the valve body movement direction) and abuts on a valve seat 401 formed on the sixth body B6. A portion 402 (hereinafter referred to as an upper protrusion), and a portion that is provided on the intermediate pressure chamber 410 side (that is, the lower side in the valve body movement direction) from the upper protrusion 402 and that is in sliding contact with the cylinder hole formed in the sixth body B6. (Hereinafter referred to as a lower piston portion) 406. A gap (clearance) of several μm is set between the lower piston portion 406 and the cylinder hole. In the intermediate pressure generating valve 400, a portion of the sixth body B6 that becomes the valve seat 401 with which the upper protruding portion 402 abuts is referred to as a “seat portion” 401 in the following description.

  The lower piston portion 406 has a substantially cylindrical shape, and an annular groove (hereinafter referred to as an outer peripheral groove) 407 is formed on the outer peripheral wall of the lower piston portion 406. In addition, a groove (hereinafter referred to as a vertical groove) is formed in the outer peripheral wall of the lower piston portion 406 so as to extend in the valve body moving direction and communicate the outer peripheral groove 407 and the intermediate pressure chamber 410. That is, the outer peripheral groove 407 communicates with the intermediate pressure chamber 410 via the vertical groove 408.

  In the intermediate pressure generating valve 400, a fuel chamber (hereinafter referred to as a second intermediate pressure chamber) is provided between the lower piston portion 406 and the upper protruding portion 402 and between the valve body 404 and the sixth body B6. 412) is provided. When the upper protrusion 402 of the valve body 404 of the intermediate pressure generating valve 400 is in contact with (sitting on) the seat 401 of the sixth body B6, the communication between the second intermediate pressure chamber 412 and the spring chamber 422 is established. The communication between the second intermediate pressure chamber 412 and the outer circumferential groove 407 and the vertical groove 408 is also blocked.

  When the pressure in the intermediate pressure chamber 410 exceeds a predetermined pressure (for example, 1 MPa) and the force acting on the valve body 404 of the intermediate pressure generating valve 400 exceeds the urging force of the coil spring 420, the valve body 404 The valve body is displaced upward in the body movement direction, and the upper protrusion 402 of the valve body and the seat portion 401 of the sixth body B6 are separated from each other, and the second intermediate pressure chamber 412 and the outer peripheral groove 407 communicate with each other. At this time, the intermediate pressure chamber 410 communicates with the spring chamber 422 via the vertical groove 408, the outer peripheral groove 407, and the second intermediate pressure chamber 412, so that the liquid fuel in the intermediate pressure chamber 410 flows out to the spring chamber 422. To do. The liquid fuel that has flowed out into the spring chamber 422 is returned to the return fuel line R1 via the return fuel chamber 320. As a result, the pressure in the intermediate pressure chamber 410 and the intermediate pressure passage communicating with the intermediate pressure chamber 410 is kept at a predetermined intermediate pressure while its pressure fluctuation is suppressed.

  Next, operation | movement of the fuel-injection apparatus 10 which concerns on this embodiment is demonstrated using FIG.1 and FIG.5-7.

  As shown in FIG. 1, when the valve body 303 of the three-position valve 300 is operated to the first position P1 (see FIG. 5) or the third position P3 (see FIG. 7), the fuel injection device 10 Communication between the port B and the return fuel line R1 is blocked. That is, the second port B is closed. In this case, in the second control valve 200, the pressure in the control pressure chamber 240 becomes the pressure in the liquid fuel supply line F1, and the pressures in the pressurizing chamber 270, the control pressure chamber 240, the control chamber 206, and the high pressure chamber 208 are equal. Become. Since the opening cross-sectional area of the low-pressure side seat 230 is set larger than the cross-sectional area of the small diameter portion 222 of the second piston 220, the second piston 220 and the second valve body 202 are axially upward due to the fuel pressure. The second valve body 202 comes into contact with the low pressure side seat 230 by being energized, and the control chamber 206 and the high pressure chamber 208 communicate with each other. As a result, the decompression valve opening chamber 90 communicating with the liquid fuel supply line F1 is disconnected from the return fuel line R1, is pressurized by receiving the pressure of the liquid fuel supply line F1, and the nozzle needle 20 for liquid fuel. Sit without lifting.

  On the other hand, when the valve element 303 of the three-position valve 300 is operated to the second position P2 (see FIG. 6), the second port B communicates with the return fuel line R1. That is, the second port B is opened. In this case, in the second control valve 200, the control pressure chamber 240 is depressurized from the pressure in the liquid fuel supply line F1, and the axial upward force acting on the second piston 220 decreases. As a result, the second piston 220 operates the second valve body 202 downward in the axial direction so as to contact the high pressure side seat 232 having the same area as the low pressure side seat 230, and the control chamber 206 and the low pressure chamber 204 communicate with each other. To do. Thus, the decompression valve opening chamber 90 communicating with the liquid fuel supply line F1 is further decompressed by communicating with the return fuel line R1, and the liquid fuel nozzle needle 20 is lifted.

  Further, in the fuel injection device 10, when the valve element 303 of the three-position valve 300 is operated to the first position P1 (see FIG. 5), both the first port A and the second port B are the return fuel line R1. Communication with is interrupted. That is, both the first port A and the second port B are closed. In this case, in the first control valve 100, the pressure in the first control pressure chamber 150 and the second control pressure chamber 160 becomes the pressure of the liquid fuel supply line F1, and the pressurization chamber 170, the first control pressure chamber 150, the second The pressures in the control pressure chamber 160 and the high pressure chamber 108 are equal. Since the cross-sectional area of the small-diameter portion 122 of the first piston 120 is set to be larger than the opening cross-sectional area of the high-pressure side seat 132, the pressurizing piston 140, the first piston 120, and the first valve body 101 are pivoted by the fuel pressure. The first valve body 101 is abutted against the high-pressure side seat 132 by being biased downward in the direction, and the control chamber 106 and the low-pressure chamber 104 communicate with each other. As a result, the pressurized valve-opening chamber 60 communicating with the return fuel line R1 is blocked from communicating with the liquid fuel supply line F1, and is maintained at the pressure of the return fuel line R1 (that is, reduced in pressure) to be used for gaseous fuel. The nozzle needle 15 sits without lifting.

  In addition, when the valve body 303 of the three-position valve 300 is operated to the second position P2 (see FIG. 6), both the first port A and the second port B communicate with the return fuel line R1. That is, the first port A and the second port B are both open. In this case, in the first control valve 100, the pressures in the first control pressure chamber 150 and the second control pressure chamber 160 are reduced from the pressure in the liquid fuel supply line F1. Since the cross-sectional area of the pressure piston 140 is substantially equal to the cross-sectional area of the small diameter portion of the first piston 120 and is set to be larger than the opening cross-sectional area of the high-pressure side sheet 132, the pressure piston 140 and the first piston 120. The first valve body 101 is urged downward in the axial direction by the fuel pressure, the first valve body 101 contacts the high pressure side seat 132, and the control chamber 106 and the low pressure chamber 104 communicate with each other. As a result, the pressurized valve-opening chamber 60 communicating with the return fuel line R1 is blocked from communicating with the liquid fuel supply line F1, and is maintained at the pressure of the return fuel line R1 (that is, reduced in pressure) to be used for gaseous fuel. The nozzle needle 15 sits without lifting.

  On the other hand, when the valve element 303 of the three-position valve 300 is operated to the third position P3 (see FIG. 7), the first port A communicates with the return fuel line R1, and the second port B communicates with the return fuel line R1. Communication with is interrupted. That is, the first port A is opened, and the second port B is closed. In this case, in the first control valve 100, the pressure in the first control pressure chamber 150 is reduced from the liquid fuel supply line F1, and the pressure in the second control pressure chamber 160 becomes the pressure in the liquid fuel supply line F1. . The opening cross-sectional area of the low-pressure side sheet 130 is set substantially equal to the opening cross-sectional area of the high-pressure side sheet 132, and the cross-sectional area of the small diameter portion 122 of the first piston 120 is substantially equal to the cross-sectional area of the pressure piston 140. Since the pressure piston 140, the first piston 120, and the first valve body 101 are biased upward in the axial direction by the fuel pressure, the first valve body 101 abuts on the low-pressure side seat 130, The control chamber 106 and the high pressure chamber 108 communicate with each other. As a result, the pressurized valve opening chamber 60 communicating with the return fuel line R1 communicates with the liquid fuel supply line F1 and is pressurized, and the gas fuel nozzle needle 15 is lifted.

  In this way, when the valve element 303 of the three-position valve 300 is operated to the first position P1, the fuel injection device 10 has both the gaseous fuel nozzle needle 15 and the liquid fuel nozzle needle 20 both. Sit without lifting. When the valve body 303 of the three-position valve 300 is operated to the second position P2, the liquid fuel nozzle needle 20 is lifted with the gaseous fuel nozzle needle 15 seated. When the valve body 303 of the three-position valve 300 is operated to the third position P3, the liquid fuel nozzle needle 20 is seated on the valve seat 14 formed on the bottom 15 of the gas fuel nozzle needle 15. In this state, the nozzle needle 15 for gaseous fuel is lifted.

  As described above, in the fuel injection device 10 according to this embodiment, the pressurization valve opening chamber 60 communicating with the low pressure side passage (return fuel line R1) communicates with the high pressure side passage (liquid fuel supply line F1). Thus, the first nozzle needle (nozzle needle 15 for gaseous fuel) is lifted and the decompression valve opening chamber 90 communicating with the high pressure side passage (liquid fuel supply line F1) is connected to the low pressure side passage (return fuel line). By communicating with R1), the pressure is reduced and the second nozzle needle (liquid fuel nozzle needle 20) is lifted. The fuel injection device 10 injects the gaseous fuel as the first fuel from the gaseous fuel injection hole 11 as the first injection hole by lifting the gaseous fuel nozzle needle 15 as the first nozzle needle, The liquid fuel nozzle needle 20 as the second nozzle needle is lifted to inject liquid fuel from the liquid fuel nozzle hole 12 as the second nozzle hole.

  The fuel injection device 10 includes a pressurization position that pressurizes the pressurization valve open chamber 60 by communicating the pressurization valve open chamber 60 and the liquid fuel supply line F1, a pressurization valve open chamber 60, and the liquid fuel supply line F1. The pressurization / depressurization of the pressurization valve-opening chamber 60 is controlled by operating the first valve body 101 at one of the decompression position where the pressurization valve-opening chamber 60 is decompressed by blocking the communication A possible first control valve 100, a pressurization position that pressurizes the decompression valve opening chamber by blocking communication between the decompression valve opening chamber 90 and the return fuel line R1, and a decompression valve opening chamber 90 and the return fuel line R1. The second control valve 200 capable of controlling the pressurization / depressurization of the decompression valve opening chamber 90 by operating the second valve body 202 at either one of the decompression position for communicating and depressurizing the decompression valve opening chamber. And have.

  The first control valve 100 communicates (always) with the liquid fuel supply line F1, and the first control pressure communicates with the return fuel line R1 from the first port A when the first port A is open. A second control pressure chamber 160 communicating with the chamber 150 and the liquid fuel supply line F1 (always) and communicating with the return fuel line R1 from the second port B when the second port B is open; A first piston 120 capable of operating the first valve body 101 in accordance with a pressure change in the first control pressure chamber 150 and the second control pressure chamber 160 is provided. When the first control pressure chamber 150 and the return fuel line R1 communicate with each other and the communication between the second control pressure chamber 160 and the return fuel line R1 is blocked at the second port B, the first control valve 100 The one valve body 101 is in the pressurizing position, while the communication between the first control pressure chamber 150 and the return fuel line R1 is blocked at the first port A, and the second control pressure chamber 160 and the return fuel line R1 are disconnected. When the communication is interrupted at the second port B, when the first control pressure chamber 150 communicates with the return fuel line R1, and when the second control pressure chamber 160 communicates with the return fuel line R1, the first piston 120 Is configured to operate the first valve body 101 to the reduced pressure position.

  The second control valve 200 communicates with the liquid fuel supply line F1 (always) and a control pressure chamber 240 that communicates from the second port B to the return fuel line R1 when the second port B is open. And a second piston 220 capable of operating the second valve body 202 in accordance with a pressure change in the control pressure chamber 240. In the second control valve 200, when the communication between the control pressure chamber 240 and the return fuel line R1 is blocked at the second port B, the second valve body 202 is in the pressurizing position, while the control pressure chamber 240 and When the return fuel line R1 communicates, the second piston 220 is configured to operate the second valve body 202 to the reduced pressure position.

  The fuel injection device 10 configured as described above is configured such that the first port A and the second port B are both closed by a valve other than the first control valve 100 and the second control valve 200, etc. In the control valve 100, the first control pressure chamber 150 and the second control pressure chamber 160 are disconnected from the return fuel line R1, and the first control pressure chamber 150 and the second control pressure chamber 160 are connected to the liquid fuel supply line. The pressure becomes F1, and the first piston 120 operates the first valve body 101 to the reduced pressure position. On the other hand, in the second control valve 200, the communication between the control pressure chamber 240 and the return fuel line R1 is cut off, and the control pressure chamber 240 becomes the pressure of the liquid fuel supply line F1, and the second valve receives the pressure. The body 202 becomes the pressure position. Thus, the pressure reducing valve opening chamber 90 is pressurized to prevent the liquid fuel nozzle needle 20 from being lifted, that is, seated, and the pressure opening valve chamber 60 is decompressed to seat the gaseous fuel nozzle needle 15. Can do.

  On the other hand, the fuel injection device 10 opens both the first port A and the second port B, so that in the first control valve 100, the first control pressure chamber 150 and the second control pressure chamber 160 are the return fuel. The first piston 120 operates the first valve body 101 to the depressurized position by communicating with the line R1 and being depressurized from the pressure of the liquid fuel supply line F1. On the other hand, in the second control valve 200, the control pressure chamber 240 communicates with the return fuel line R1, the control pressure chamber 240 is depressurized from the pressure in the liquid fuel supply line F1, and the second piston 220 is moved to the second valve. Manipulate body 202 to a reduced pressure position. As a result, the pressurized valve opening chamber 60 is depressurized to seat the gaseous fuel nozzle needle 15, and the depressurized valve opening chamber 90 is depressurized to allow the liquid fuel nozzle needle 20 (with respect to the gaseous fuel nozzle needle 15). ) Can be lifted.

  Further, the fuel injection device 10 opens the first port A and closes the second port B, so that in the first control valve 100, the first control pressure chamber 150 communicates with the return fuel line R1. The pressure is reduced, and the second control pressure chamber 160 is disconnected from the return fuel line R1 and becomes the pressure of the liquid fuel supply line F1, and in this case, the first valve body 101 is in the pressurizing position. On the other hand, in the second control valve 200, the communication between the control pressure chamber 240 and the return fuel line R1 is cut off, resulting in the pressure of the liquid fuel supply line F1, and the second valve body 202 is in the pressurizing position. Thus, the pressurized valve opening chamber 60 is pressurized and the gaseous fuel nozzle needle 15 is lifted, and the pressure reducing valve opening chamber 90 is pressurized to change the liquid fuel nozzle needle 20 (to the gaseous fuel nozzle needle 15). ) Can be seated.

  As described above, the fuel injection device 10 according to the present embodiment opens / closes the first port A, that is, communicates / connects the first control pressure chamber 150 of the first control valve 100 and the return fuel line R1 (low pressure side passage). Blocking and opening / closing of the second port B, that is, the second control pressure chamber 160 of the first control valve 100, the control pressure chamber 240 of the second control valve 200, and the return fuel line R1 (low pressure side passage) By simply controlling communication / blocking, pressurization / depressurization of the pressurization opening chamber by the first control valve 100, that is, lift / seat of the nozzle needle 15 for the gaseous fuel as the first nozzle needle, and the second control valve The pressurization / depressurization of the decompression valve opening chamber by 200, that is, the seating / lift of the liquid fuel nozzle needle 20 as the second nozzle needle can be controlled separately. Thereby, the fuel injection device 10 can individually control the two nozzle needles without using a plurality of solenoid-driven valves, and can inject gaseous fuel and liquid fuel at different timings.

  In addition, the fuel injection device 10 according to the present embodiment has a first position P1 that blocks communication between the first port A and the return fuel line R1, and blocks communication between the second port B and the return fuel line R1, A second position P2 for communicating the first port A and the return fuel line R1 and for communicating the second port B and the return fuel line R1, and a second port for communicating the first port A and the return fuel line R1. A three-position valve 300 in which the valve body is operated at any one of the third position P3 that blocks communication between B and the return fuel line R1 is further provided. One three-position valve is used for communication / blocking between the first port A and the return fuel line R1 (low pressure side passage) and communication / blocking between the second port B and the return fuel line R1 (low pressure side passage). Can only be realized.

  Further, in the fuel injection device 10 according to the present embodiment, the first nozzle needle is a gas fuel nozzle needle 15 through which gas fuel is injected from the gas fuel injection hole 11 by lifting, and the second nozzle needle is The liquid fuel nozzle needle 20 injects liquid fuel from the liquid fuel injection hole 12 by lifting, and the high-pressure side passage is a liquid that is a conduit for supplying the pressurized liquid fuel to the fuel injection device 10. The fuel supply line F1 and the low-pressure side passage are assumed to be a return fuel line R1 that is a pipe that returns liquid fuel that has not been injected by the fuel injection device 10 toward the fuel tank. The high-pressure liquid fuel that is pressurized and supplied to the fuel injection device 10 and injected from the liquid fuel injection hole 12, and the fuel tank (not shown) from the fuel injection device 10 without being injected from the liquid fuel injection hole 12. The first valve body 101 of the first control valve 100 and the second valve body 202 of the second control valve 200 described above are respectively utilized by utilizing the pressure difference of the low-pressure liquid fuel (return fuel) returned toward Can be operated.

  In the fuel injection device 10 according to the present embodiment, the first port A is opened / closed, that is, the first control pressure chamber 150 and the return fuel line R1 (low pressure side passage) are communicated / blocked, and the second port. The opening / closing of B, that is, the communication / blocking of the second control pressure chamber 160 and the return fuel line R1, is controlled by switching the valve body position of one three-position valve. The method for controlling the opening / closing of the port A and the second port B is not limited to the three-position valve. Any valve mechanism that can control the opening / closing of the first port A and the second port B separately can be applied to the present invention.

  Further, in the fuel injection device 10 according to the present embodiment, the first nozzle needle is a gas fuel nozzle needle 15 through which gas fuel is injected from the gas fuel injection hole 11 by lifting, and the second nozzle needle is The liquid fuel nozzle needle 20 in which the liquid fuel is injected from the liquid fuel injection hole 12 by being lifted is used, but the aspect of the fuel injection device 10 is not limited to this. Any fuel injection device provided with two nozzle needles may be used. For example, the present invention can also be applied to a fuel injection device that injects different types of liquid fuel by lifting the first and second nozzle needles.

  Further, in the fuel injection device 10 according to the present embodiment, the low pressure side passage is the return fuel line R1, and the high pressure side passage is the liquid fuel supply line F1, but the low pressure side passage according to the present invention and The aspect of the high-pressure side passage is not limited to this. The pressure difference between the low-pressure side passage and the high-pressure side passage can lift the corresponding nozzle needle by the pressurization / depressurization of the decompression valve opening chamber and the pressurization / depressurization of the pressurization valve opening chamber, respectively. The present invention can be applied to any fuel injection device provided with two fuel passages (pipes) having such a pressure difference and two hydraulic passages (pipes).

DESCRIPTION OF SYMBOLS 10 Fuel injection apparatus 11 Injection hole for gaseous fuel (1st injection hole)
12 Liquid fuel injection hole (second injection hole)
15 Nozzle needle for gaseous fuel (first nozzle needle, outer nozzle needle)
20 Nozzle needle for liquid fuel (second nozzle needle, inner nozzle needle)
60 Pressurizing valve opening chamber 90 Depressurizing valve opening chamber 100 First control valve (control valve for pressurizing valve opening chamber)
101 1st valve body (valve body of control valve for pressurization valve opening chamber)
120 1st piston 150 1st control pressure chamber 160 2nd control pressure chamber 200 2nd control valve (control valve for decompression valve-opening chamber)
202 2nd valve body (valve body of control valve for decompression valve opening chamber)
220 2nd piston 240 Control pressure chamber 300 3 position valve 303 Valve body of 3 position valve 400 Intermediate pressure generating valve F1 Liquid fuel supply line (high pressure side passage)
F2 to F11 Liquid fuel passage (high-pressure side passage)
R1 return fuel line (low pressure side passage)
R2 to R5 Return fuel passage (low pressure side passage)

Claims (3)

The pressurization valve opening chamber communicating with the low pressure side passage is pressurized by communicating with the high pressure side passage, the first nozzle needle is lifted, and the decompression valve opening chamber communicating with the high pressure side passage is formed in the low pressure side passage. A fuel injection device in which the second nozzle needle is lifted by being depressurized by communication,
Pressurization position that pressurizes the pressurization valve opening chamber by connecting the pressurization valve open chamber and the high pressure side passage, and the communication between the pressurization valve open chamber and the high pressure side passage is cut off to depressurize the pressurization valve opening chamber A first control valve capable of controlling the pressurization / depressurization of the pressurization valve opening chamber by operating the first valve body at any one of the depressurization position and
A pressurizing position that blocks communication between the decompression valve opening chamber and the low pressure side passage and pressurizes the decompression valve opening chamber; and a decompression position that communicates the decompression valve opening chamber and the low pressure side passage and decompresses the decompression valve opening chamber. A second control valve capable of controlling the pressurization / depressurization of the decompression valve opening chamber by operating the second valve body in any one of the above,
Have
The first control valve is
A first control pressure chamber communicating with the high-pressure side passage and communicating with the low-pressure side passage from the first port when the first port is open;
A second control pressure chamber communicating with the high pressure side passage and communicating with the low pressure side passage from the second port when the second port is opened;
A first piston capable of operating the first valve body in accordance with pressure changes in the first control pressure chamber and the second control pressure chamber;
With
When the first control pressure chamber communicates with the low pressure side passage and the communication between the second control pressure chamber and the low pressure side passage is interrupted, the first valve body is in the pressurizing position,
On the other hand, when the communication between the first control pressure chamber and the low-pressure side passage is cut off and the communication between the second control pressure chamber and the low-pressure side passage is cut off, the first control pressure chamber and the low-pressure side passage communicate with each other. And when the second control pressure chamber and the low pressure side passage communicate with each other, the first piston is configured to operate the first valve body to the decompression position,
The second control valve
A control pressure chamber communicating with the high-pressure side passage and communicating with the low-pressure side passage from the second port when the second port is opened;
A second piston capable of operating the second valve body in response to a pressure change in the control pressure chamber;
With
When the communication between the control pressure chamber and the low pressure side passage is interrupted, the second valve body is in the pressurizing position,
On the other hand, when the control pressure chamber communicates with the low-pressure side passage, the second piston is configured to operate the second valve body to the reduced pressure position. The fuel injection device according to claim 1,
A first position that blocks communication between the first port and the low-pressure side passage and blocks communication between the second port and the low-pressure side passage, and communicates the first port and the low-pressure side passage, and the second port and the low-pressure side. The valve element is operated at any one of a second position where the passage is communicated and a third position where the first port is communicated with the low pressure side passage and the communication between the second port and the low pressure side passage is blocked. A fuel injection device further comprising a three-position valve. The fuel injection device according to claim 1 or 2,
The first nozzle needle is a nozzle needle for gaseous fuel in which gaseous fuel is injected from the nozzle hole for gaseous fuel by lifting,
The second nozzle needle is a liquid fuel nozzle needle in which the liquid fuel is injected from the liquid fuel injection hole by lifting,
The high-pressure side passage is a liquid fuel supply line that is a pipe that supplies the pressurized liquid fuel to the fuel injection device.
The low-pressure side passage is a return fuel line that is a conduit that returns liquid fuel that has not been injected by the fuel injection device toward the liquid fuel tank.

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