JPH11210589A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a bouncing phenomenon of a valve when a two-way solenoid valve is opened and closed. SOLUTION: When a two-way solenoid valve is opened, high pressure fuel filled in a back pressure chamber 7 of an injector 5 flows out to a drain passage 9 via a first orifice 51 and a second orifice 52 larger in inner diameter than the first orifice 51. The center axis of the first orifice 51 and that of the second orifice 52 are shifted from each other. The high pressure fuel flowing out of an outlet of the first orifice 51 therefore flows out to the drain passage 9 via the second orifice 52 after colliding with the tapered passage wall surface of the second orifice 52. Accordingly, when the two-way solenoid valve 6 is opened, the flow velocity of the high pressure fuel flowing out to the drain passage 9 from the back pressure chamber 7 can be made slow so as to restrain a valve 35 from colliding against a stopper 36 at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for injecting high-pressure fuel stored in a common rail into an internal combustion engine, and particularly to a valve which can avoid a bounce phenomenon of a valve at the time of opening and closing the valve and close the valve. The present invention relates to a two-way solenoid valve of a pressure-accumulation type fuel injection device capable of improving valve responsiveness.

[0002]

2. Description of the Related Art Conventionally, a high-pressure fuel is stored in a kind of surge tank called a common rail, and the stored high-pressure fuel is injected and supplied to an internal combustion engine by opening a needle. For example, JP-A-59
No. 165858) is known. This 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 amount of fuel injected from the fuel injection nozzle.

Here, a pressure-accumulation type fuel injection device which realizes injection into an internal combustion engine by replacing the three-way solenoid valve with a two-way solenoid valve and switching back pressure of a fuel injection nozzle is shown in FIG. As shown in FIG. 6 and FIG.
High pressure pump 102 which pumps fuel from 01 to high pressure
A high-pressure fuel supplied from the high-pressure pump 102 to store the high-pressure fuel, and a fuel injection nozzle for an internal combustion engine (hereinafter, referred to as an injector) for injecting the high-pressure fuel stored in the common rail 103 into the internal combustion engine. ) 104 and a two-way solenoid valve 106 for switching the back pressure of the nozzle needle 105 can be considered (prior art).

The injector 104 has an injection hole 10
7 and nozzle body 10 in which oil reservoir 108 is formed
9, a nozzle needle 105 slidably disposed in the nozzle body 109, an injector body 110 connected to the rear end of the nozzle body 109, and a slidably disposed inside the injector body 110. Piston 1
11, a pressure pin 112 connecting the nozzle needle 105 and the piston 111, and a nozzle needle 105
And a coil spring 113 for urging the valve in the valve closing direction. A control chamber (back pressure chamber) 114 is provided between the rear end of the injector body 110 and the piston 111.
Are formed.

The two-way solenoid valve 106 includes a valve body 117 having a valve seat member 116 having an orifice 115 therein, and a high-pressure fuel in a back pressure chamber 114 supplied to the fuel tank 10.
1, a valve 119 for opening and closing a drain passage 118 for returning the valve 119, an electromagnetic solenoid 120 for attracting the valve 119 by electromagnetic force, a coil spring 121 for urging the valve 119 in a valve closing direction, and an opening degree of the valve 119. And a stopper 122 to be determined. The valve seat member 116 has a fuel passage 123 formed in the injector body 110 and a back pressure chamber 1 in addition to the orifice 115.
A communication path 124 that communicates with the communication path 14 is formed.

[0006]

However, in the prior art shown in FIGS. 5 and 6, the two-way solenoid valve 106 is not used.
Of the valve 119 has a plate shape instead of a needle 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 119 is accelerated. 119 collides with the stopper 122.
This causes a problem that the valve 119 bounces (bounces) for a while after the valve 119 collides with the stopper 122.

In the prior art shown in FIGS. 5 and 6, even if the two-way solenoid valve 106 is open, that is, even if the valve 119 has the orifice 115 open, the fuel passage from the common rail 103 to the fuel passage is not changed. The high-pressure fuel flows into the back pressure chamber 114 via the communication passage 123 and the communication passage 124,
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 the high-pressure fuel from the back pressure chamber 114 through the orifice 115 causes resistance, so that the speed at which the valve 119 closes the orifice 115 decreases, and the two-way solenoid valve 106 Even after the valve is closed, a rebound phenomenon (bounce phenomenon) occurs due to the high-pressure fuel, which causes a problem that the valve 119 has poor valve closing response.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent a bounce phenomenon of a valve when a two-way solenoid valve is opened and closed, and to provide a valve closing response when the two-way solenoid valve is closed. It is an object of the present invention to provide a fuel injection device capable of improving performance.

[0009]

According to the first aspect of the present invention, when the two-way solenoid valve is opened, the valve opens the fixed throttle and sits on the stopper. When the high-pressure fuel flows out of the back pressure chamber, the fuel injection nozzle opens 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 an inner diameter larger than that of the upstream fixed throttle. The flow velocity 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 collides with the stopper slowly, even if the valve collides with the stopper, it is possible to prevent the valve from bouncing from the stopper, and the bounce phenomenon occurs when the two-way solenoid valve is opened. Can be suppressed.

When the two-way solenoid valve is closed, the flow rate of the high-pressure fuel flowing from the back pressure chamber through the upstream fixed throttle and the downstream fixed throttle to the fuel discharge passage is slow as described above. Fuel spill is not very resistant to valve displacement. Therefore, the speed at which the valve closes the fixed throttle is not reduced, and the occurrence of a 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.

According to the second aspect of the invention, when the two-way solenoid valve is opened, the valve opens the fixed throttle and sits on the stopper. When the high-pressure fuel flows out of the back pressure chamber, the fuel injection nozzle opens 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 flows into the fuel discharge passage after hitting the passage wall surface of the downstream fixed throttle. Therefore, the flow velocity of the high-pressure fuel flowing from the back pressure chamber to the fuel discharge passage via the upstream fixed throttle and the downstream fixed throttle can be reduced. Therefore, since the valve collides with the stopper slowly, even if the valve collides with the stopper, it is possible to prevent the valve from bouncing from the stopper, and the bounce phenomenon occurs when the two-way solenoid valve is opened. Can be suppressed.

According to the third aspect of the invention, the flow rate of the high-pressure fuel flowing from the back pressure chamber through the upstream fixed throttle and the downstream fixed throttle to the fuel discharge passage can be reduced. Even when the tip shape is a plate shape, when the two-way solenoid valve is opened, it is not accelerated so much by the high-pressure fuel flowing out of the back pressure chamber through the fixed throttle, and the valve slowly sits on the stopper. Thus, the occurrence of the bounce phenomenon of the valve when the two-way solenoid valve is opened can be suppressed.

According to the fourth aspect of the present invention, the back pressure chamber communicates with the upstream fixed throttle communicating with the back pressure chamber and the downstream fixed throttle communicating the upstream fixed throttle and the fuel discharge passage. The flow velocity of the high-pressure fuel flowing from the fuel discharge passage into the fuel discharge passage can be reduced. As a result, the occurrence of a bounce phenomenon of the valve when the two-way solenoid valve is opened and closed can be suppressed.

According to the fifth aspect of the present invention, when the two-way solenoid valve is opened, an electromagnetic force is generated in the solenoid by energizing the solenoid, and the valve is attracted by the electromagnetic force. Sit on the stopper. Thereby, when the valve opens the fixed throttle, the high-pressure fuel in the back pressure chamber flows out to the fuel discharge passage via the upstream fixed throttle and the downstream fixed throttle. When the two-way solenoid valve is closed, the energization of the solenoid is stopped so that the electromagnetic force of the solenoid is demagnetized. Is closed. Thus, the outflow of the high-pressure fuel from the back pressure chamber to the fuel discharge passage is stopped.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Structure of Embodiment] FIGS. 1 to 3
FIG. 1 shows an embodiment of the present invention, and FIG. 1 is a diagram showing an overall configuration of a pressure accumulating fuel injection device.

The accumulator-type fuel injection device 1 of this embodiment includes a high-pressure pump 3 that is electronically controlled by an engine control unit (hereinafter, referred to as an ECU), and a common rail 4 to which high-pressure fuel is supplied from the high-pressure pump 3. A fuel injection valve (fuel injection nozzle: hereinafter referred to as an injector) 5 for injecting high-pressure fuel into a combustion chamber of an internal combustion engine (for example, a diesel engine: hereinafter referred to as an engine); and a two-way solenoid valve 6 electronically controlled by an ECU And a back pressure chamber 7 provided in the injector 5 and a fuel discharge passage (hereinafter referred to as a drain passage).
9, the first and second aperture forming members 11, 1
2 is provided.

Here, the ECU includes an engine speed sensor, a control rack position sensor, an injection timing (advance angle).
An optimal injection amount and injection timing are calculated based on information from sensors and an accelerator (throttle) opening sensor or the like, and actuators such as the high-pressure pump 3 and the two-way solenoid valve 6 are electronically controlled.

The high-pressure pump 3 is composed of a feed pump for pumping fuel from the fuel tank 2 and a supply pump for discharging the fuel pumped by the feed pump to a common rail 4 at a high pressure. The common rail 4 corresponds to the fuel pressure accumulating section of the present invention, and has a relatively high pressure (common rail pressure: for example, 20 MPa to 20 MPa).
A type of surge tank that accumulates high-pressure fuel of 120 MPa), and is configured to communicate with the injector 5.

Next, the structure of the injector 5 of this embodiment will be described with reference to FIGS. Here, FIG. 2 is a diagram showing the injector and the two-way solenoid valve. This injector 5 is attached to each cylinder of the engine.
The injector 5 includes an injector body 13 having one or two or more injection holes 10 formed at a distal end thereof, a nozzle needle 14 slidably supported in the injector body 13, and a nozzle needle 14. A piston 16 is connected to the rear end via a pressure pin 15 and reciprocates integrally with the nozzle needle 14.

The injector body 13 includes the nozzle body 1
7, a tip packing 18, a nozzle holder 19 and the like. Inside the nozzle body 17, an oil reservoir 20 is formed around the nozzle needle 14 for always filling with high-pressure fuel. This oil sump 20
It 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 end surface of the tip packing 18 forms a restricting portion that restricts the maximum lift amount of the nozzle needle 14.

The nozzle holder 19 constitutes a cylinder in which a long hole 23 for slidably supporting the piston 16 is formed in a longitudinal direction of a central portion. And, at the rear end of the long hole 23,
The above-described back pressure chamber 7 that opens at the rear end surface of the nozzle holder 19 is formed between the back pressure chamber 7 and the front end surface of the first throttle forming member 11. In addition, an inlet pipe 24 connected to an unillustrated introduction pipe communicating with the common rail 4 is fastened and fixed to the nozzle holder 19. The 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. .

The nozzle needle 14 is disposed on the same axis as the center axis of the two-way solenoid 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 and a fuel passage is formed between the tip of the nozzle needle 14 and the nozzle body 17 so that the oil reservoir 20 and the injection hole 10 communicate with each other to perform fuel injection to the engine. Is done. When the nozzle is closed, the tip of the nozzle needle 14 sits on the seat surface of the nozzle body 17 and the injection of the high-pressure fuel ends.

A coil spring (needle urging means) 27 for urging 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 center axis of the two-way solenoid valve 6, and
3 is slidably supported on the inner peripheral surface.

Next, the two-way solenoid valve 6 will be described with reference to FIGS. Here, FIG. 3 is a view showing the two-way solenoid valve 6. As shown in FIGS. 1 and 2, the two-way solenoid valve 6 is brought into contact with the rear end of the nozzle holder 19 of the injector 5 in a liquid-tight manner by a retaining nut 31 in the rear end surface of the nozzle holder 19. A valve body 32 which is fastened and fixed to the valve body, 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. A valve 35 slidably displaced in the valve body 32,
A stopper 36 for regulating the maximum lift of the valve 35
And a coil spun ring (corresponding to valve urging means of the present invention) 37 for urging the valve 35 in the valve closing direction.

A connector 38 for supplying power to the electromagnetic coil 34 is attached to the upper end (rear end) of the retaining nut 31 in the figure. The first and second valve bodies 32 are provided in recesses 39 opened to communicate with the back pressure chamber 7.
The aperture forming members 11 and 12 are fitted in a liquid-tight manner.
A fuel chamber 40 having an inner diameter larger than that of the recess 39 is formed in the valve body 32. This fuel chamber 40
Is connected to the fuel tank 2 via a drain passage 9 provided in the valve body 32 and the like.

When power is supplied to the electromagnetic coil 34,
For example, when the switch 41 is closed, it is magnetized and becomes an electromagnet. The electromagnetic coil 34 generates a magnetomotive force by being energized through the connector 38 to magnetize the iron core 33.
The valve 35 has a plate-shaped seal portion 42 on the front end side and a rod-shaped portion 43 on the rear end side. When the valve is opened, the rod portion 43 of the valve 35 is seated on the distal end surface of the stopper 36. When the valve is closed, the sealing portion 4 of the valve 35 is closed.
2 is seated on the rear end surface of the second aperture forming member 12.

As long as the valve 35 can be reciprocated in one piece, either the entirety of the valve 35 or a separate part may be used. Stopper 36
Has a rod portion 44 that forms a gap with the rear end surface of the rod portion 43 of the valve 35. The upper end (rear end) of the coil spring 37 is held by the large-diameter portion 45 of the stopper 36, and the lower end (end) of the coil spring 37 is held by the stepped portion 46 of the valve 35.

Next, the first and second aperture forming members 11 and 12
Will be described with reference to FIGS. Here, FIG. 4 is a diagram 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. The first and second throttle forming members 11 and 12 are provided with a cylindrical collar 50 screwed to the inner periphery of the retaining nut 31. By fastening to the outer periphery of the nozzle holder 19 and the outer periphery of the valve body 32 of the two-way solenoid 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.

The first and second aperture forming members 11 and 12
Is made of alloy steel such as SCM420 or carbon steel,
The two-way solenoid valve 6 is formed in an annular plate shape centered on the same axis as the central axis of the valve 35. The first throttle forming member 11 has a back pressure chamber 7 in addition to the communication path 26.
The orifice for making the flow velocity of the high-pressure fuel flowing out of the back pressure chamber 7 into the drain passage 9 slower than the flow velocity of the high-pressure fuel flowing into the inside of the fuel passage 25 and the communication passage 26 is smaller than the inner diameter of the fuel passage 25 and the communication passage 26. Is formed.

The orifice of this embodiment is a first orifice whose center axis is slightly shifted from the center axis of the first throttle forming member 11 toward the communication passage 26 (corresponding to an upstream fixed throttle of the present invention).
51, and a second orifice (corresponding to a downstream fixed throttle of the present invention) 52 formed on the same axis as the central axis of the second throttle forming 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, while the second orifice 52 is
And at the same position as the central axis of the valve 35.

The first orifice 51 is connected to the back pressure chamber 7.
This is a portion that narrows the passage cross-sectional area of the first passage that communicates with the second orifice 52. The second orifice 52 is a part that narrows the passage cross-sectional area of the second passage that connects the first orifice 51 and the drain passage 9. The second orifice 52 is a valve seat member having an inner diameter that is about 1.4 to 1.6 times larger than the inner diameter of the first orifice 51.

The lower ends (front ends) of the first and second orifices 51 and 52 in the drawing are formed such that the inner diameter increases toward the back pressure chamber 7. Then, the first orifice 51
Is disposed so as to face the tapered passage wall surface of the inlet of the second orifice 52. In the present embodiment, the first orifice 51 is provided on the upstream side in the flow direction of the high-pressure fuel flowing 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. Have been.

[Operation of the Embodiment] Next, the operation of the accumulator type fuel injection device 1 of this embodiment will be briefly described with reference to FIGS.

1) When the nozzle is opened The electromagnetic coil 34 is controlled electronically by the ECU.
Is turned on, a magnetomotive force is generated in the electromagnetic coil 34 to magnetize the iron core 33. As a result, the valve 35 is attracted to the iron core 33, so that the seal portion 42 opens the outlet of the second orifice 52, and the rod portion 43
Is seated on the rod-shaped portion 44.

As described above, when the two-way solenoid valve 6 is opened,
The high-pressure fuel filling 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 fuel passage 21 and the oil sump 20
The high-pressure fuel inside is injected from the injection hole 10 into the combustion chamber of the engine.

Here, the high-pressure fuel in the back pressure chamber 7 flows into the fuel chamber 40 through the second orifice 52 having an inner diameter larger than that of the first orifice 51 in addition to the first orifice 51. As compared with the technique described in the above, the flow velocity of the high-pressure fuel flowing from the back pressure chamber 7 to the drain passage 9 becomes slow. Also, the center axis of the first orifice 51 and the second orifice 52
The high-pressure fuel flowing out of the outlet of the first orifice 51 hits the tapered passage wall surface of the inlet of the second orifice 52 and then flows into the fuel chamber 40 by shifting the center axis of the first orifice 51. The flow velocity of the high-pressure fuel flowing from inside into the drain passage 9 becomes slow.

In the case of the injector 5 of this embodiment, while the two-way solenoid valve 6 is open, that is, while the valve 35 opens the first and second orifices 51 and 52. The high-pressure fuel flows from the common rail 4 into the back pressure chamber 7 through the fuel passages 21 and 25 and the communication passage 26, and drains from the back pressure chamber 7 through the first and second orifices 51 and 52 and the fuel chamber 40. The high-pressure fuel flows out into the passage 9.

Therefore, when the two-way solenoid valve 6 is opened, when the valve 35 is attracted to the iron core 33, it is not assisted by the high-pressure fuel flowing into the fuel chamber 40 from the outlet of the second orifice 52, The valve 35 collides with the stopper 36 slowly. As a result, the valve 35 can be prevented from bouncing off from the stopper 36, so that the valve 35
Bounce phenomenon can be suppressed.

2) When the nozzle is closed The electromagnetic coil 34 is controlled electronically by the ECU.
Is stopped (turned off), the coil spring 37
The valve 35 is returned to the initial position, that is, the position at which the outlet of the second orifice 52 is closed, by the urging force in the valve closing direction, so that the seal portion 42 of the valve 35 is seated on the rear end face of the second throttle forming member 12. I do.

Thus, when the two-way solenoid valve 6 is closed,
From common rail 4 to fuel passages 21 and 25 and communication passage 2
The inside of the back pressure chamber 7 is filled with the high-pressure fuel supplied through 6. Then, the nozzle needle 14, the pressure pin 1
5 and the piston 16 start descending, and the tip of the nozzle needle 14 is seated on the seat surface of the nozzle body 17, so that the injection of the high-pressure fuel from the injection hole 10 to the engine ends.

When the two-way solenoid valve 6 is closed, the first orifice 51 and the second orifice 5
Since the flow rate of the high-pressure fuel flowing into the fuel chamber 40 via the second valve 2 is low, the high-pressure fuel flows out of the first and second valves 35 through the valve 35.
There is not much resistance to the closing action of the orifices 51, 52, that is, the seating operation of the second throttle forming member 12 on the rear end face. 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 from becoming slow.

[Effects of the Embodiment] As described above, the two-way solenoid valve 6 of the pressure-accumulation type fuel injection device 1 of the present embodiment has 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 flowing out of the outlet into the fuel chamber 40 can be made slower than in the related art, the bounce phenomenon of the valve 35 can be suppressed. Further, since the occurrence of the bounce phenomenon after the two-way solenoid valve 6 is closed can be suppressed, the valve closing response from turning off the electromagnetic coil 34 by the ECU to closing the valve 35 can be improved.

[Other Embodiments] In this embodiment, the first and second
The orifices (upstream and downstream fixed throttles) 51 and 52 are separately provided in the first and second throttle forming members 11 and 12, however, the upstream and downstream fixed throttles are formed in one throttle forming member. Is also good. Also, the upstream and downstream fixed throttles are connected to the two-way solenoid valve 6.
May be formed in the valve body 32 or the nozzle holder 19 of the injector 5. Further, the nozzle holder 1
9, a diaphragm forming member is fitted into a recess opened at the rear end, and a passage on the side facing the front end surface of the diaphragm forming member is a back pressure chamber (control chamber) 7, and a passage on the side facing the rear end surface of the diaphragm forming member. May be a drain passage (fuel discharge passage) 9.

In this embodiment, a coil spring 37 for generating an urging force in the valve closing direction is used as the valve urging means.
Although an example in which is used is shown, another elastic body such as rubber or an air cushion may be used as the valve urging means.
Further, in the present embodiment, an example is shown in which the coil spring 27 that generates an urging force in the needle closing direction is used as the needle urging means, but other elastic materials such as rubber and air cushion are used as the needle urging means. You may use your body.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a pressure accumulating fuel injection device (Example).

FIG. 2 is a sectional view showing an injector and a two-way solenoid valve (Example).

FIG. 3 is a sectional view showing a two-way solenoid valve (Example).

FIG. 4 is a cross-sectional view showing first and second aperture forming members (Example).

FIG. 5 is a schematic diagram 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]

 DESCRIPTION OF SYMBOLS 1 Accumulation type fuel injection device (fuel injection device) 4 Common rail (fuel accumulation unit) 5 Injector (fuel injection nozzle) 6 Two-way solenoid valve 7 Back pressure chamber 9 Drain passageway (fuel discharge passage) 10 Injection hole 11 First throttle formation Member (upstream throttle forming member) 12 Second throttle forming member (downstream throttle 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 First orifice (upstream fixed throttle) 52 Second orifice (downstream fixed throttle)

Claims (5)

[Claims] 1. A fuel pressure accumulating section for accumulating high pressure fuel, and (b) a back pressure chamber to which high pressure fuel is supplied from the fuel accumulating section, from which high pressure fuel flows out. Then, a fuel injection nozzle that opens to inject high-pressure fuel into the internal combustion engine; (c) a valve that opens and closes a fuel discharge passage for discharging high-pressure fuel in the back pressure chamber of the fuel injection nozzle; A two-way solenoid valve having a stopper on which a valve is seated; and (d) a fixed throttle that communicates with the back pressure chamber and the fuel discharge passage and is closed by the valve when the two-way solenoid valve is closed. The fixed throttle is provided with an upstream fixed throttle provided on the back pressure chamber side, and a downstream fixed provided on an opposite side to the back pressure chamber side and having a larger inner diameter than the upstream fixed throttle. Fuel injection characterized by comprising a throttle apparatus. 2. A fuel pressure accumulating section for accumulating high pressure fuel, and (b) a back pressure chamber to which high pressure fuel is supplied from the fuel accumulating section, from which the high pressure fuel flows out. Then, a fuel injection nozzle that opens to inject high-pressure fuel into the internal combustion engine; (c) a valve that opens and closes a fuel discharge passage for discharging high-pressure fuel in the back pressure chamber of the fuel injection nozzle; (D) a two-way solenoid valve having a stopper on which a valve is seated; The fixed throttle is provided on the back pressure chamber side, and is provided on an upstream fixed throttle provided at a position where a central axis is shifted with respect to the valve, and provided on a side opposite to the back pressure chamber side. And
The fuel injection device is characterized in that the valve and the central axis are formed of the same downstream fixed throttle. 3. The fuel injection device according to claim 1, wherein the valve has a plate-like tip shape that closes the downstream fixed throttle when the two-way solenoid valve is closed. Characteristic fuel injection device. 4. The fuel injection device according to claim 1, wherein the fuel injection nozzle has an injection hole at one end for injecting high-pressure fuel into the internal combustion engine, and an injection hole at the other end. The back pressure chamber is opened, and the upstream fixed throttle is formed on an upstream throttle forming member connected in a state where one end face is in liquid-tight contact with the other end face of the fuel injection nozzle, and The fixed throttle is formed on a downstream throttle forming member connected in a state where one end surface thereof is in liquid-tight contact with the other end surface of the upstream throttle forming member, and the other end surface of the downstream throttle forming member includes the fixed throttle. A fuel injection device, wherein the two-way solenoid valve is seated when the valve is closed. 5. The fuel injection device according to claim 1, wherein the two-way solenoid valve includes an electromagnetic solenoid that attracts the valve by an electromagnetic force, and a valve that closes the valve in a valve closing direction. A fuel injection device comprising valve biasing means for biasing the fuel.