JP3924888B2 - Fuel injection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection device that injects high-pressure fuel accumulated in a common rail to an internal combustion engine, and in particular, can avoid a bounce phenomenon of a valve at the time of an on-off valve and improve valve closing response. The present invention relates to a two-way solenoid valve of an accumulator type fuel injection device that is capable of operating.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a pressure-accumulation fuel injection apparatus that accumulates high-pressure fuel in a type of surge tank called a common rail, and injects and supplies the accumulated high-pressure fuel to an internal combustion engine by opening a needle (for example, Japanese Patent Laid-Open No. Sho 59). -165858) is known. The fuel injection device includes a fuel injection nozzle that injects high-pressure fuel into an internal combustion engine, and a three-way solenoid valve that controls the injection timing and the injection amount of fuel injected from the fuel injection nozzle.
[0003]
Here, as the pressure accumulation type fuel injection device that realizes injection to the internal combustion engine by replacing the three-way solenoid valve with a two-way solenoid valve and switching the back pressure of the fuel injection nozzle, FIG. 5 and FIG. As shown in FIG. 2, a high pressure pump 102 that pumps fuel from the fuel tank 101 to high pressure, a high pressure fuel supplied from the high pressure pump 102 to store the high pressure fuel, and a pressure stored in the common rail 103 An internal combustion engine fuel injection nozzle (hereinafter referred to as an injector) 104 that injects high-pressure fuel into the internal combustion engine and a two-way electromagnetic valve 106 for switching the back pressure of the nozzle needle 105 can be considered (conventional technology). Technology).
[0004]
The injector 104 includes a nozzle body 109 in which an injection hole 107 and an oil reservoir 108 are formed, a nozzle needle 105 slidably disposed in the nozzle body 109, and an injector connected to the rear end portion of the nozzle body 109. A main body 110, a piston 111 slidably disposed in the injector main body 110, a pressure pin 112 that connects the nozzle needle 105 and the piston 111, and a coil spring that biases the nozzle needle 105 in the valve closing direction. 113 is provided. A control chamber (back pressure chamber) 114 is formed between the piston body 111 and the rear end portion of the injector body 110.
[0005]
The two-way solenoid valve 106 includes a valve body 117 including a valve seat member 116 having an orifice 115, a valve 119 for opening and closing a drain passage 118 for returning high-pressure fuel in the back pressure chamber 114 into the fuel tank 101, An electromagnetic solenoid 120 that attracts the valve 119 by electromagnetic force, a coil spring 121 that biases the valve 119 in the valve closing direction, and a stopper 122 that determines the opening degree of the valve 119 are provided. In addition to the orifice 115, the valve seat member 116 is formed with a communication passage 124 that connects the fuel passage 123 formed in the injector body 110 and the back pressure chamber 114.
[0006]
[Problems to be solved by the invention]
However, in the prior art shown in FIGS. 5 and 6, the seal portion (tip shape) of the valve 119 of the two-way solenoid valve 106 is not a needle shape but a plate shape. For this reason, when the two-way solenoid valve 106 is opened, the valve 119 is seated on the stopper 122. However, the valve 119 is accelerated by the outflow of high-pressure fuel from the back pressure chamber 114 through the orifice 115, so that the valve is operated at high speed. 119 collides with the stopper 122. As a result, after the valve 119 collides with the stopper 122, there is a problem that the valve 119 rebounds (bounces) for a while.
[0007]
5 and 6, even if the two-way solenoid valve 106 is open, that is, even if the valve 119 is opening the orifice 115, the fuel passage 123 and the communication path from the common rail 103. High pressure fuel flows into the back pressure chamber 114 via the passage 124, and high pressure fuel flows out of the back pressure chamber 114 into the drain passage 118 via the orifice 115. For this reason, when the two-way solenoid valve 106 is closed, the flow of high-pressure fuel from the back pressure chamber 114 through the orifice 115 becomes resistance, so that the speed at which the valve 119 closes the orifice 115 becomes slow and the two-way electromagnetic Even after the valve 106 is closed, a rebound phenomenon (bounce phenomenon) occurs due to the high-pressure fuel, so that the valve closing response of the valve 119 is poor.
[0008]
OBJECT OF THE INVENTION
It is an object of the present invention to avoid the occurrence of valve bounce when the two-way solenoid valve is opened and closed, and to improve the valve closing response when the two-way solenoid valve is closed. An object of the present invention is to provide a fuel injection device capable of performing
[0009]
[Means for Solving the Problems]
According to the first aspect of the present invention, when the two-way solenoid valve is opened, the valve opens the fixed throttle and is seated on the stopper. Then, when the high pressure fuel flows out from the back pressure chamber, the fuel injection nozzle is opened and the high pressure fuel is injected into the internal combustion engine.
At this time, by shifting the central axis of the upstream fixed throttle and the central axis of the downstream fixed throttle, the high-pressure fuel that has passed through the upstream fixed throttle hits the passage wall surface of the downstream fixed throttle and then flows out into the fuel discharge passage. Therefore, it is possible to slow the flow rate of the high pressure fuel flowing into the fuel discharge passage via the upstream fixed throttle and a downstream fixed throttle from the back pressure chamber.
Therefore, since the valve slowly collides with the stopper, even if the valve collides with the stopper, it is possible to suppress the valve from bouncing off from the stopper, so that the valve may bounce when the two-way solenoid valve is opened. Can be suppressed.
[0010]
When the two-way solenoid valve is closed, as described above, the flow rate of the high-pressure fuel flowing out from the back pressure chamber to the fuel discharge passage through the upstream fixed throttle and the downstream fixed throttle is slow. Is not very resistant to valve displacement. Therefore, the speed at which the valve closes the fixed throttle is not slow, and the occurrence of the bounce phenomenon after the two-way solenoid valve is closed can be suppressed, so that the valve closing response of the valve can be improved.
[0011]
According to the second aspect of the present invention, when the two- way solenoid valve is opened, the valve opens the fixed throttle and is seated on the stopper. Then, when the high pressure fuel flows out from the back pressure chamber, the fuel injection nozzle is opened and the high pressure fuel is injected into the internal combustion engine.
At this time, in addition to the upstream fixed throttle, the high pressure fuel in the back pressure chamber flows into the fuel discharge passage through the downstream fixed throttle having a larger inner diameter than the upstream fixed throttle. The flow rate of the high-pressure fuel flowing into the fuel discharge passage via the fixed throttle and the downstream fixed throttle can be reduced.
Therefore, since the valve slowly collides with the stopper, even if the valve collides with the stopper, it is possible to suppress the valve from bouncing off from the stopper, so that the valve may bounce when the two-way solenoid valve is opened. Can be suppressed.
[0012]
According to the third aspect of the present invention, the flow velocity of the high-pressure fuel flowing out from the back pressure chamber to the fuel discharge passage through the upstream fixed throttle and the downstream fixed throttle can be reduced. Even in the plate shape, when the two-way solenoid valve is opened, it is not accelerated so much by the high-pressure fuel flowing out from the back pressure chamber through the fixed throttle, and the valve is slowly seated on the stopper. Thereby, generation | occurrence | production of the bounce phenomenon of the valve | bulb at the time of valve opening of a two-way solenoid valve can be suppressed.
[0013]
According to the fourth aspect of the present invention, the fuel is discharged from the back pressure chamber via the upstream fixed throttle communicating with the back pressure chamber and the downstream fixed throttle communicating with the upstream fixed throttle and the fuel discharge passage. The flow rate of the high-pressure fuel flowing out into the passage can be reduced. Thereby, generation | occurrence | production of the bounce phenomenon of the valve at the time of valve opening of a two-way solenoid valve can be suppressed.
[0014]
According to the fifth aspect of the present invention, when the two-way solenoid valve is opened, the electromagnetic solenoid is energized, so that an electromagnetic force is generated in the electromagnetic solenoid, and the valve is attracted by the electromagnetic force and is seated on the stopper. To do. Thereby, when the valve opens the fixed throttle, the high-pressure fuel in the back pressure chamber flows out to the fuel discharge passage through the upstream fixed throttle and the downstream fixed throttle. Also, when the two-way solenoid valve is closed, energization to the solenoid is stopped, so that the electromagnetic force of the solenoid is demagnetized, and the biasing force in the valve closing direction of the valve biasing means works, and the downstream fixed throttle Is blocked. Thereby, the outflow of the high-pressure fuel from the back pressure chamber to the fuel discharge passage is stopped.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
[Configuration of Example]
1 to 3 show an embodiment of the present invention, and FIG. 1 is a diagram showing the overall configuration of a pressure accumulation type fuel injection device.
[0016]
The accumulator fuel injection device 1 of this embodiment includes a high pressure pump 3 that is electronically controlled by an engine control device (hereinafter referred to as ECU) (not shown), a common rail 4 to which high pressure fuel is supplied from the high pressure pump 3, and an internal combustion engine. A fuel injection valve (fuel injection nozzle: hereinafter referred to as an injector) 5 for supplying high-pressure fuel into a combustion chamber of a diesel engine (hereinafter referred to as an engine), a two-way electromagnetic valve 6 electronically controlled by an ECU, and an injector 1 and second throttle forming members 11 and 12 provided between a back pressure chamber 7 provided in 5 and a fuel discharge passage (hereinafter referred to as a drain passage) 9.
[0017]
Here, the ECU calculates an optimal injection amount and injection timing based on information from each sensor such as an engine speed sensor, a control rack position sensor, an injection timing (advance angle) sensor, and an accelerator (throttle) opening sensor. Actuators such as the high-pressure pump 3 and the two-way solenoid valve 6 are electronically controlled.
[0018]
The high-pressure pump 3 includes a feed pump that pumps fuel from the fuel tank 2 and a supply pump that discharges the fuel pumped by the feed pump to the common rail 4 at a high pressure. The common rail 4 corresponds to the fuel pressure accumulating portion of the present invention, and is a type of surge tank that accumulates a high pressure fuel having a relatively high pressure (common rail pressure: 20 MPa to 120 MPa, for example) and communicates with the injector 5. It is configured.
[0019]
Next, the structure of the injector 5 of a present Example is demonstrated based on FIG. 1 and FIG. Here, FIG. 2 is a view showing an injector and a two-way solenoid valve.
The injector 5 is attached to each cylinder of the engine. The injector 5 includes an injector body 13 in which one or more injection holes 10 are formed at the tip, a nozzle needle 14 slidably supported in the injector body 13, and the nozzle needle 14 The piston 16 is connected to the rear end side via a pressure pin 15 and reciprocally moves integrally with the nozzle needle 14.
[0020]
The injector body 13 includes a nozzle body 17, a tip packing 18, a nozzle holder 19, and the like. Inside the nozzle body 17, an oil sump 20 for always filling the high-pressure fuel around the nozzle needle 14 is formed. The oil reservoir 20 is always in communication with the common rail 4 via the fuel passage 21. The tip packing 18 is fastened and fixed by a retaining nut 22 while being sandwiched between the nozzle body 17 and the nozzle holder 19. The tip surface of the tip packing 18 constitutes a restricting portion that restricts the maximum lift amount of the nozzle needle 14.
[0021]
The nozzle holder 19 constitutes a cylinder in which a long hole 23 that slidably supports the piston 16 is formed in the longitudinal direction of the central portion. The back pressure chamber 7 that opens at the rear end surface of the nozzle holder 19 is formed between the rear end portion of the long hole 23 and the front end surface of the first diaphragm forming member 11. In addition, an inlet pipe 24 connected to an introduction pipe (not shown) that communicates with the common rail 4 is fastened and fixed to the nozzle holder 19. A fuel passage 25 branched from the fuel passage 21 formed in the inlet pipe 24 and the nozzle holder 19 communicates with the back pressure chamber 7 via a communication passage 26 formed in the first throttle forming member 11. .
[0022]
The nozzle needle 14 is disposed on the same axis as the central axis of the two-way electromagnetic valve 6 and is slidably supported on the inner periphery of the nozzle body 17. When the nozzle is opened, the nozzle needle 14 is lifted to form a fuel passage between the tip of the nozzle needle 14 and the nozzle body 17, and the oil reservoir 20 and the injection hole 10 communicate with each other to inject fuel into the engine. Made. When the nozzle is closed, the tip of the nozzle needle 14 is seated on the seat surface of the nozzle body 17 and the injection of high-pressure fuel is terminated.
[0023]
A coil spring (needle biasing means) 27 that biases the nozzle needle 14 in the valve closing direction is mounted between the large diameter portion of the pressure pin 15 and the nozzle holder 19. The piston 16 is disposed on the same axis as the central axis of the two-way electromagnetic valve 6, and is slidably supported on the inner peripheral surface of the long hole 23 of the nozzle holder 19.
[0024]
Next, the two-way solenoid valve 6 will be described with reference to FIGS. Here, FIG. 3 is a view showing the two-way electromagnetic valve 6.
As shown in FIGS. 1 and 2, the two-way solenoid valve 6 is configured such that the rear end surface of the nozzle holder 19 is retained by the retaining nut 31 in a state of being in liquid-tight contact with the rear end portion of the nozzle holder 19 of the injector 5. A valve body 32 fastened and fixed to the core, an iron core 33 disposed on the rear end side of the valve body 32, and an electromagnetic coil (electromagnetic solenoid of the present invention) 34 wound around a storage portion of the iron core 33. The valve 35 slidably displaces in the valve body 32, the stopper 36 that regulates the maximum lift amount of the valve 35, and the coil spun ring that urges the valve 35 in the valve closing direction (the valve urging of the present invention). 37 corresponding to the means).
[0025]
A connector 38 for supplying power to the electromagnetic coil 34 is assembled to the upper end (rear end) of the retaining nut 31 in the figure. In the valve body 32, the first and second throttle forming members 11 and 12 are fitted in a liquid-tight manner in a recess 39 that is open to communicate with the back pressure chamber 7. A fuel chamber 40 having an inner diameter larger than that of the recess 39 is formed in the valve body 32. The fuel chamber 40 communicates with the fuel tank 2 via a drain passage 9 provided in the valve body 32 or the like.
[0026]
The iron core 33 is magnetized and becomes an electromagnet when the electromagnetic coil 34 is energized, for example, when the switch 41 is closed. The electromagnetic coil 34 receives a current through the connector 38 to generate a magnetomotive force and magnetize the iron core 33. The valve 35 has a plate-shaped seal portion 42 on the front end side and a rod-like portion 43 on the rear end side. When the valve is opened, the rod-shaped portion 43 of the valve 35 is seated on the front end surface of the stopper 36, and when the valve is closed, the seal portion 42 of the valve 35 is seated on the rear end surface of the second throttle forming member 12.
[0027]
In addition, as long as the valve | bulb 35 can be reciprocally displaced integrally, the whole may be comprised by the integral part, or it may be comprised by another body. The stopper 36 has a rod-shaped portion 44 that forms a gap with the rear end surface of the rod-shaped portion 43 of the valve 35. The coil spring 37 has an upper end portion (rear end portion) shown in the figure held by the large-diameter portion 45 of the stopper 36, and a lower end portion (tip end) shown in the drawing is held by the stepped portion 46 of the valve 35.
[0028]
Next, the first and second diaphragm forming members 11 and 12 will be described with reference to FIGS. Here, FIG. 4 is a view showing the first and second aperture forming members 11 and 12.
The first and second throttle forming members 11 and 12 correspond to the upstream and downstream throttle forming members of the present invention, and a cylindrical collar 50 that is screwed into the inner periphery of the retaining nut 31 is provided on the injector 5. By being fastened to the outer periphery of the nozzle holder 19 and the outer periphery of the valve body 32 of the two-way electromagnetic valve 6, the nozzle holder 19 is fixed while being sandwiched between the rear end surface of the nozzle holder 19 and the front end surface of the valve body 32.
[0029]
Further, the first and second throttle forming members 11 and 12 are made of alloy steel such as SCM420 or carbon steel, for example, and are annular plates centered on the same axis as the central axis of the valve 35 of the two-way solenoid valve 6. It is formed into a shape. In addition to the communication passage 26 described above, the first throttle forming member 11 has a flow velocity of the high pressure fuel flowing out from the back pressure chamber 7 into the drain passage 9 rather than a flow velocity of the high pressure fuel flowing into the back pressure chamber 7. The orifice for slowing down is formed so as to have an inner diameter smaller than the inner diameters of the fuel passage 25 and the communication passage 26.
[0030]
The orifice of this embodiment includes a first orifice 51 (corresponding to the upstream fixed throttle of the present invention) 51 whose center axis is slightly shifted to the communication path 26 side from the central axis of the first throttle forming member 11, and the second throttle formation. It comprises a second orifice 52 (corresponding to the downstream fixed throttle of the present invention) 52 formed on the same axis as the central axis of the member 12. That is, the first orifice 51 is formed at a position slightly deviated from the central axis of the piston 16 of the injector 5 and the valve 35 of the two-way solenoid valve 6, but the second orifice 52 is formed of the piston 16 and the valve 35. It is formed at the same position as the central axis.
[0031]
The first orifice 51 is a portion that restricts the passage cross-sectional area of the first passage that communicates the back pressure chamber 7 and the second orifice 52. The second orifice 52 is a part that narrows the cross-sectional area of the second passage that communicates the first orifice 51 and the drain passage 9. The second orifice 52 is a valve seat member having an inner diameter that is 1.4 to 1.6 times larger than the inner diameter of the first orifice 51.
[0032]
In addition, the lower end side (front end side) of the first and second orifices 51 and 52 is formed so that the inner diameter becomes larger toward the back pressure chamber 7 side. The outlet of the first orifice 51 is disposed so as to face the tapered passage wall surface of the inlet of the second orifice 52. In this embodiment, the first orifice 51 is provided on the upstream side in the flow direction of the high-pressure fuel flowing out from the back pressure chamber 7 to the drain passage 9, and the second orifice 52 is provided on the downstream side of the first orifice 51. It has been.
[0033]
(Effects of Example)
Next, the operation of the pressure-accumulation fuel injection device 1 of this embodiment will be briefly described with reference to FIGS.
[0034]
1) When the electromagnetic coil 34 is energized (turned on) by electronic control by the ECU when the nozzle is opened, a magnetomotive force is generated in the electromagnetic coil 34 to magnetize the iron core 33. As a result, the valve 35 is adsorbed to the iron core 33, the seal portion 42 opens the outlet of the second orifice 52, and the rod-shaped portion 43 is seated on the rod-shaped portion 44 of the stopper 36.
[0035]
As described above, when the two-way electromagnetic valve 6 is opened, the high-pressure fuel filled in the back pressure chamber 7 is discharged to the drain passage 9 through the first and second orifices 51 and 52 and the fuel chamber 40. . Then, the nozzle needle 14, the pressure pin 15 and the piston 16 start to rise, and the tip of the nozzle needle 14 is lifted from the seat surface of the nozzle body 17, so that the high-pressure fuel in the fuel passage 21 and the oil reservoir 20 is injected into the injection hole. 10 is injected into the combustion chamber of the engine.
[0036]
Here, since the high-pressure fuel in the back pressure chamber 7 flows into the fuel chamber 40 through the second orifice 52 having a larger inner diameter than the first orifice 51 in addition to the first orifice 51, In comparison, the flow velocity of the high-pressure fuel flowing out from the back pressure chamber 7 into the drain passage 9 is reduced. Further, by shifting the central axis of the first orifice 51 and the central axis of the second orifice 52, the high pressure fuel that has flowed out from the outlet of the first orifice 51 hits the tapered passage wall surface of the inlet of the second orifice 52 and then the fuel. Since the fuel flows out into the chamber 40, the flow rate of the high-pressure fuel flowing out from the back pressure chamber 7 into the drain passage 9 is further reduced.
[0037]
In the case of the injector 5 of the present embodiment, the common rail 4 is also used while the two-way solenoid valve 6 is open, that is, while the valve 35 is opening the first and second orifices 51 and 52. The high pressure fuel flows into the back pressure chamber 7 through the fuel passages 21 and 25 and the communication passage 26, and enters the drain passage 9 from the back pressure chamber 7 through the first and second orifices 51 and 52 and the fuel chamber 40. High pressure fuel is flowing out.
[0038]
Therefore, when the valve 35 is adsorbed to the iron core 33 when the two-way solenoid valve 6 is opened, the valve 35 is not assisted by the high pressure fuel flowing out from the outlet of the second orifice 52 into the fuel chamber 40. Slowly collides with the stopper 36. Thereby, since the valve 35 can be prevented from bouncing off from the stopper 36, the occurrence of the bounce phenomenon of the valve 35 can be suppressed.
[0039]
2) When the energization of the electromagnetic coil 34 is stopped (turned off) by electronic control by the ECU when the nozzle is closed, the valve 35 is moved to the initial position, that is, the second position by the biasing force of the coil spring 37 in the valve closing direction. Since the outlet of the orifice 52 is returned to the closed position, the seal portion 42 of the valve 35 is seated on the rear end surface of the second throttle forming member 12.
[0040]
Thus, when the two-way solenoid valve 6 is closed, the back pressure chamber 7 is filled with the high-pressure fuel supplied from the common rail 4 through the fuel passages 21 and 25 and the communication passage 26. Then, the nozzle needle 14, the pressure pin 15 and the piston 16 start to descend, and the tip of the nozzle needle 14 is seated on the seat surface of the nozzle body 17, so that the injection of high-pressure fuel from the injection hole 10 to the engine is completed. .
[0041]
Here, when the two-way solenoid valve 6 is closed, the flow rate of the high-pressure fuel flowing out from the back pressure chamber 7 into the fuel chamber 40 through the first orifice 51 and the second orifice 52 is slow. However, the first and second orifices 51 and 52 are blocked by the valve 35, that is, the second throttle forming member 12 is not so much resistant to the seating operation on the rear end surface. Therefore, when the two-way solenoid valve 6 is closed, the valve closing speed at which the valve 35 closes the first and second orifices 51 and 52 can be suppressed.
[0042]
[Effects of Examples]
As described above, the two-way solenoid valve 6 of the accumulator fuel injection device 1 of the present embodiment flows into the fuel chamber 40 from the outlet of the second orifice 51 both when the electromagnetic coil 34 is on and when it is off. Since the flow rate of the high-pressure fuel can be made slower than that of the prior art, the occurrence of the bounce phenomenon of the valve 35 can be suppressed. Moreover, since the occurrence of the bounce phenomenon after the two-way electromagnetic valve 6 is closed can be suppressed, the valve closing response from when the electromagnetic coil 34 is turned off by the ECU until the valve 35 is closed can be improved.
[0043]
[Other Examples]
In this embodiment, the first and second orifices (upstream and downstream fixed throttles) 51 and 52 are separately provided in the first and second throttle forming members 11 and 12, but the upstream and downstream fixed throttles are provided. It may be formed on a single diaphragm forming member. Further, the upstream and downstream fixed throttles may be formed in the valve body 32 of the two-way solenoid valve 6 or the nozzle holder 19 of the injector 5. Further, the throttle forming member is fitted into a recess opened at the rear end of the nozzle holder 19, and the passage on the side where the front end surface of the throttle forming member faces is a back pressure chamber (control chamber) 7, and the rear end surface of the throttle forming member is The facing side passage may be a drain passage (fuel discharge passage) 9.
[0044]
In the present embodiment, an example is shown in which a coil spring 37 that generates a biasing force in the valve closing direction is used as the valve biasing means. However, other elastic bodies such as rubber and air cushions are used as the valve biasing means. May be used. Further, in this embodiment, an example is shown in which the coil spring 27 that generates the urging force in the needle valve closing direction is used as the needle urging means. However, other elasticity such as rubber and air cushion is used as the needle urging means. The body may be used.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an overall configuration of an accumulator fuel injection device (Example).
FIG. 2 is a cross-sectional view showing an injector and a two-way solenoid valve (Example).
FIG. 3 is a cross-sectional view showing a two-way solenoid valve (Example).
FIG. 4 is a sectional view showing first and second diaphragm forming members (Example).
FIG. 5 is a schematic view showing the overall configuration of a pressure accumulating fuel injection device (prior art).
FIG. 6 is a cross-sectional view showing a two-way solenoid valve (prior art).
[Explanation of symbols]
1 Accumulated fuel injection system (fuel injection system)
4 Common rail (fuel accumulator)
5 Injector (fuel injection nozzle)
6 Two-way solenoid valve 7 Back pressure chamber 9 Drain passage (fuel discharge passage)
10 injection hole 11 first throttle forming member (upstream side throttle forming member)
12 Second diaphragm forming member (downstream diaphragm forming member)
14 Nozzle needle 16 Piston 20 Oil reservoir 34 Electromagnetic coil (electromagnetic solenoid)
35 Valve 36 Stopper 37 Coil spring (valve biasing means)
51 1st orifice (upstream fixed throttle)
52 Second orifice (downstream fixed throttle)

Claims (5)

(A) a fuel accumulator for accumulating high-pressure fuel;
(B) a fuel injection nozzle that has a back pressure chamber to which high pressure fuel is supplied from the fuel accumulator, and opens when the high pressure fuel flows out of the back pressure chamber to inject high pressure fuel into the internal combustion engine;
(C) a two-way solenoid valve having a valve for opening and closing a fuel discharge passage for discharging high-pressure fuel in the back pressure chamber of the fuel injection nozzle, and a stopper on which the valve is seated when the valve is opened;
(D) communicating with the back pressure chamber and the fuel discharge passage, and including a fixed throttle closed by the valve when the two-way solenoid valve is closed,
The fixed throttle is provided on the back pressure chamber side, and is provided on the opposite side to the back pressure chamber side on the upstream side fixed throttle provided at a position shifted from the central axis with respect to the valve , The fuel injection device is characterized in that the valve and the central axis are made of the same downstream fixed throttle. The fuel injection device according to claim 1,
The fixed throttle, the upper stream side fixed throttle provided on the back pressure chamber side, and the disposed on the opposite side with respect to the back pressure chamber side, and an inner diameter larger downstream fixed throttle than the upstream fixed throttle A fuel injection device comprising: The fuel injection device according to claim 1 or 2,
The fuel injection device according to claim 1, wherein the valve has a plate shape in a tip shape that closes the downstream fixed throttle when the two-way solenoid valve is closed. The fuel injection device according to any one of claims 1 to 3,
The fuel injection nozzle has an injection hole for injecting high-pressure fuel into the internal combustion engine at one end, and the back pressure chamber opens at the other end surface,
The upstream fixed throttle is formed in an upstream throttle forming member connected in a state where one end surface thereof is in liquid-tight contact with the other end surface of the fuel injection nozzle,
The downstream fixed throttle is formed on a downstream throttle forming member connected in a state where one end surface is in liquid-tight contact with the other end surface of the upstream throttle forming member,
The fuel injection device, wherein the valve is seated on the other end surface of the downstream side throttle forming member when the two-way solenoid valve is closed. The fuel injection device according to any one of claims 1 to 4,
The two-way solenoid valve includes an electromagnetic solenoid that attracts the valve by electromagnetic force, and a valve biasing unit that biases the valve in a valve closing direction.

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