JP3528304B2 - Fuel injection device - Google Patents

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 into a diesel engine.

[0002]

2. Description of the Related Art Conventionally, there is a fuel injection device for accumulating high pressure fuel in a kind of surge tank called a common rail and injecting the accumulated high pressure fuel into a diesel engine. In this fuel injection device, there is known a technique of reducing the initial injection rate by discharging the back pressure (high pressure fuel) of the hydraulic piston through an orifice formed in the movable valve body at the start of fuel injection.

However, when pilot injection is performed prior to the main injection, if the main injection is started after the pilot injection and before the movable valve body returns to the initial position,
Since the high pressure fuel flows out through the outer periphery of the movable valve body,
The initial injection rate of the main injection becomes high. When the main injection is performed just before the movable valve body returns, the main injection is performed with the movable valve body returning to the initial position, or the movable valve body has not returned to the initial position. The main injection is performed in. Therefore, there is a problem that the initial injection rate becomes low or high, that is, so-called asymmetrical injection.

Therefore, the present applicant has filed Japanese Patent Application No. 6-2721.
In No. 40, a fuel injection device that can perform stable injection while lowering the initial injection rate of main injection was proposed. In this fuel injection device, as shown in FIG. 12, a throttle member 110 having an orifice 100 is housed in a housing 210 formed in a nozzle holder 200, and a bottom surface 211 of the housing 210 and a body of the three-way solenoid valve 300 are housed. It is closely fixed to the end face 310. This allows
A pressure chamber 220 is formed between the hydraulic piston 400 fitted into the nozzle holder 200 and the throttle member 110, and the pressure chamber 220 is formed in the high pressure passage 320 or the low pressure passage 330 which is switched by the three-way solenoid valve 300 through the orifice 100. Communicated.

According to this structure, since the position of the throttle member 110 is fixed, all the high-pressure fuel flowing out of the pressure chamber 220 at the start of fuel injection passes through the orifice 100.
Therefore, the outflow rate of the fuel flowing out of the pressure chamber 220 is suppressed, and the back pressure of the hydraulic piston 400 slowly decreases, so that the initial injection rate becomes low. Even when the pilot injection is performed prior to the main injection, the pressure chamber 2
When the fuel is discharged from 20, the orifice 100
Therefore, the asymmetrical injection in which the initial injection rate of the main injection becomes low or high does not occur.

[0006]

However, in the fuel injection device of the prior application, the throttle member 110 is mounted on the bottom surface 21 of the housing portion 210.
1 and the body end surface 310 of the three-way solenoid valve 300 are closely fixed. Therefore, when the dimensional accuracy of the diaphragm member 110 or the housing portion 210 is low, for example, the length of the diaphragm member 110 is longer than the depth of the housing portion 210 and the diaphragm member 1
When a step is generated between the end surface of the nozzle holder 10 and the end surface of the nozzle holder 200, the high pressure passage 2 formed in the nozzle holder 200
A minute gap is generated between the high pressure passage 320 formed in the three-way solenoid valve 300 and the fuel cell 30.

On the other hand, from the depth of the storage portion 210, the diaphragm member 1
If the length of 10 is shorter, the throttle member 110 cannot be tightly fixed between the bottom surface 211 of the storage portion 210 and the body end surface 310 of the three-way solenoid valve 300, and the throttle member 110 is stored inside the storage portion 210. Since it moves, it adversely affects the injection start timing and the injection end timing.

Therefore, the diaphragm member 1 is formed by the method of the prior application.
When fixing 10, the length of the diaphragm member 110 and the depth of the storage portion 210 need to be controlled with an accuracy of several microns, so that the number of processing steps (processing time) is significantly increased and the cost is increased. There is a problem of inviting. The present invention has been made based on the above circumstances, and an object thereof is to provide a fuel injection device capable of significantly reducing the number of processing steps.

[0009]

In order to achieve the above object, the following constitution is adopted for each claim. In Claim 1, the nozzle which the built-in needle lifts and opens a nozzle hole
And hold this nozzle and drive the needle
Nozzle holder with a built-in piston for
High pressure fuel is supplied through a fuel passage having a
Fuel pressure is transferred to the needle lifter via the piston.
Pressure chamber that acts to suppress the
A high pressure passage and the low pressure passage
And a passage for connecting to the fuel passage by selecting one of
The switching means and the passage switching means are fastened to the nozzle holder.
A fuel injection device having a fastening means for connecting the
A diaphragm member that forms an orifice, and the diaphragm member
The fuel passage is arranged on the pressure chamber side or the counter pressure chamber side.
And an annular intermediate member forming a part of
Either the nozzle holder or the passage switching means
A recess is formed, and the intermediate member and the diaphragm are formed in the recess.
And the tightening force of the fastening means.
As a result, the intermediate member is compressed and deformed to the plastic region.
The diaphragm member is fixed .

According to a second aspect of the present invention, in the fuel injection device according to the first aspect, the throttle member is connected to the orifice.
A taper where the road cross-sectional area expands toward the pressure chamber side
It is characterized in that a hole is formed .

[0011]

[0012]

[0013]

[0014]

(Advantageous Effects of the Invention) (Claim 1) By fastening the passage switching means to the nozzle holder by the fastening means, the intermediate member housed in the recess together with the throttle member is compressed, and the nozzle holder and the passage switching means are compressed. It plastically deforms until the mounting surfaces are in close contact with each other. In the present invention, since the dimensional error between the recess and the diaphragm member can be absorbed by the deformation of the intermediate member, it is necessary to control the depth of the recess and the total length of the diaphragm member housed in the recess with an accuracy of several microns. The number of processing steps can be reduced significantly.

(Claim 2) In the throttle member, the cross-sectional area of the passage of the orifice is directed toward the opposite pressure chamber side.
Once the taper hole that expands in a taper shape is formed
So, when the fuel flows out of the pressure chamber, it passes through the orifice
Depending on the fuel flow rate,
The flow rate of fuel passing through the tank is higher. As a result, fuel
When fuel flows into the pressure chamber through the passage,
Since the material pressure rises rapidly, the jetting out becomes good.

[0016]

[0017]

[0018]

[0019]

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the fuel injection device of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is an enlarged cross-sectional view of a main part including a pressure chamber. The fuel injection device 1 (see FIG. 4) of the present embodiment is connected to an introduction pipe (not shown) branched from a common surge tank (not shown) and attached to each cylinder of a diesel engine (not shown). ing. As shown in FIG. 4, this fuel injection device 1 includes a nozzle body 2, a needle 3 (see FIG. 5), a tip packing 4, a nozzle holder 5, a hydraulic piston 6, and a three-way solenoid valve 7 (passage switching means of the present invention). , And the fixed orifice 8 (throttle member of the present invention) and the like.

As shown in FIG. 5, the nozzle body 2 is provided with an injection hole 9 for ejecting high-pressure fuel at its tip, and slidably holds the needle 3 on its inner peripheral portion. The nozzle body 2 has a suck hole 10 communicating with the injection hole 9,
A seat surface 11 connected to the suck hole 10, a fuel reservoir 12 communicating with the suck hole 10 at the time of fuel injection, and a fuel supply passage 13 for supplying high-pressure fuel to the fuel reservoir 12 are provided.

As shown in FIG. 5, the needle 3 has a seat portion 3a formed on the outer peripheral surface of the tip which has a conical shape.
The needle 3 descends and the seat portion 3a is seated on the seat surface 11 formed on the nozzle body 2 (state shown in FIG. 5).
As a result, the gap between the fuel reservoir 12 of the nozzle body 2 and the suck hole 10 is cut off, and the fuel injection is terminated. Further, when the needle 3 is lifted (moved upward in the drawing) and the seat portion 3a is separated from the seat surface 11, the suck hole 1
High-pressure fuel is supplied to 0, and fuel is injected from the injection hole 9.

The needle 3 is accommodated in the nozzle holder 5 and the back pressure acting on the rear end surface of the hydraulic piston 6 because the pressure of the high-pressure fuel flowing into the fuel reservoir 12 of the nozzle body 2 acts to lift the needle 3. The biasing force of the generated spring 14 acts in the direction of pushing down the needle 3. Then, when the back pressure of the hydraulic piston 6 rises above the valve closing pressure, the back pressure of the hydraulic piston 6 is pushed down, the seat portion 3a is seated on the seat surface 11, and when the back pressure of the hydraulic piston 6 falls below the valve opening pressure. Lift upward in the drawing to seat 3a
Moves away from the seat surface 11.

The tip packing 4 is sandwiched between the nozzle body 2 and the nozzle holder 5 to regulate the maximum lift amount of the needle 3. The tip packing 4 has a communication path 1 communicating with a fuel supply path 13 formed in the nozzle body 2.
5 is formed.

The nozzle holder 5 is formed with a long hole 16 penetrating its central portion in the longitudinal direction (vertical direction in FIG. 4).
The hydraulic piston 6 is slidably fitted into the elongated hole 16 and an intermediate member 17 is provided above the hydraulic piston 6.
(See FIG. 1) and a fixed orifice 8 (described later) are housed, and a pressure chamber 18 for introducing back pressure of the hydraulic piston 6 is formed between the hydraulic piston 6 and the fixed orifice 8. The upper end surface 5a of the nozzle holder 5 (three-way solenoid valve 7
The upper portion of the long hole 16 that is open to the mounting surface) is a storage portion 19 (recess of the present invention) that stores the intermediate member 17 and the fixed orifice 8, and the long hole 16 into which the hydraulic piston 6 is fitted and inserted. It has a larger diameter than the inner diameter of.

The nozzle holder 5 is provided with a fuel introduction path 21 for introducing the high-pressure fuel supplied from the introduction pipe through the pipe joint 20. The fuel introduction passage 21 is formed so as to extend in the longitudinal direction of the nozzle holder 5, one end of which is opened at the lower end surface on the side of the tip packing 4 and communicates with the communication passage 15 of the tip packing 4, and the other end is the three-way solenoid valve 7 Side upper surface 5
It has an opening at a.

The hydraulic piston 6 is connected to the needle 3 via a pressure pin 22 passing through the inside of the spring 14 arranged in the elongated hole 16 and is responsive to the back pressure of the hydraulic piston 6 (fuel pressure in the pressure chamber 18). The inside of the long hole 16 is displaced. The valve body of the present invention is composed of the needle 3 and the hydraulic piston 6 described above. The nozzle body 2, the tip packing 4, and the nozzle holder 5 described above are fastened by a retaining nut 23, as shown in FIGS. 4 and 5.

As shown in FIG. 4, the three-way solenoid valve 7 is installed on the upper part of the nozzle holder 5, and the retaining nut 2 is installed.
4 (the fastening means of the present invention), the body 25 is fastened to the nozzle holder 5, the coil 26 arranged above the body 25, the iron core 27, the armature 28, and the outer valve 29 and the inner valve 30 (both are incorporated therein). The passage switching valve of the present invention) and the like. In addition,
The coil 26, the iron core 27, the armature 28, the outer valve 29, the inner valve 30, and the like are retaining nuts 31 that cover the entire body together with the body 25 in a tubular shape.
Is assembled by.

In the body 25, the high pressure passage 3 communicating with the fuel introduction passage 21 of the nozzle holder 5 and filled with high pressure fuel.
2. Low-pressure passage 33 for discharging the overflowed fuel,
A communication passage 34 is formed so as to be able to communicate with either one of the high pressure passage 32 and the low pressure passage 33. In addition,
The high-pressure passage 32 opens at the lower end surface 25 a of the body 25 (a surface where the nozzle holder 5 is assembled) and is fluid-tightly connected to the fuel introduction passage 21 formed in the nozzle holder 5.

The coil 26 generates a magnetic force by being energized via a connector 35 provided at the upper end of the three-way solenoid valve 7. When the coil 26 is energized, the iron core 27 is magnetized and becomes an electromagnet. The armature 28 is arranged in the space formed by the spacer 36 between the body 25 and the iron core 27, and is attracted to the iron core 27 side serving as an electromagnet when the coil 26 is energized.

The outer valve 29 is slidably fitted in a fitting hole formed in the center of the body 25, and
The iron core 27 is connected to the armature 28 at its upper end.
Is urged downward in the drawing by a spring 37 arranged on the inner peripheral portion of the. Therefore, the outer valve 29 moves together with the armature 28 according to the energization state of the coil 26, and the position with respect to the body 25 changes.

Specifically, when the coil 26 is not energized, it is pushed downward in the drawing by the urging force of the spring 37, and the low-pressure passage 33 formed in the body 25.
When the coil 26 is energized by moving to an initial position (see FIG. 1) that shuts off between the communication path 34 and the communication path 34, the spring 3
A lift position in which the low pressure passage 33 and the communication passage 34 communicate with each other by being attracted to the iron core 27 side against the biasing force of the No. 7 (see FIG. 3).
Move to. Further, the outer valve 29 has a coil 26
When the body 2 is not energized, that is, when it is pushed down to the initial position by the biasing force of the spring 37, the body 2
An oil passage 38 that connects the high-pressure passage 32 and the communication passage 34 formed in 5 is formed.

The inner valve 30 is disposed inside the outer valve 29, and the outer valve 29 serves as the inner valve 3.
It is configured to be slidable with respect to zero. The inner valve 30 shuts off the oil passage 38 formed in the outer valve 29 when the outer valve 29 is attracted to the iron core 27 side together with the armature 28 by energizing the coil 26.

The fixed orifice 8 is accommodated in the accommodating portion 19 formed in the nozzle holder 5 together with the intermediate member 17, and the bottom surface 19a of the accommodating portion 19 (see FIGS. 1 and 2) and the body 25 of the three-way solenoid valve 7 are accommodated. It is fixed tightly between the two. A fuel passage 39 is formed in the fixed orifice 8 to connect the communication passage 34 formed in the body 25 and the pressure chamber 18.

As shown in FIG. 1, the fuel passage 39 has a large diameter passage portion 39a communicating with the communication passage 34, a small diameter passage portion 39b communicating with the pressure chamber 18, and a large diameter passage portion 39a extending from the small diameter passage portion 39b. It consists of a funnel section 39c. The large diameter passage portion 39a is provided so that the passage inner diameter is approximately the same as the communication passage 34, and the small diameter passage portion 39b has a passage inner diameter smaller than that of the large diameter passage portion 39a, and forms the orifice of the present invention. Funnel 39c are provided from the large-diameter passage portion 39a in a funnel shape cross-sectional area is gradually reduced toward the small-diameter passage portion 39 b, the
The tapered hole portion of the invention is formed.

The intermediate member 17, for example made of cold-rolled steel sheet if, inner diameter substantially the same diameter of the round hole 17a of the elongated hole 16 in the central portion
(A part of the fuel passage of the present invention) is provided in an open annular shape, and the lower side of the fixed orifice 8 (pressure
It is stored in the chamber 18 side) . That is, the intermediate member 17 is stored in the storage portion 19 before the fixed orifice 8.
However, the total length of the fixed orifice 8 accommodated in the accommodating portion 19 is set to be shorter than the depth of the accommodating portion 19, but when the fixed orifice 8 is accommodated together with the intermediate member 17, as shown in FIG. Slightly protrudes from the upper end surface 5a of the nozzle holder 5. Specifically, for example, when the thickness t of the intermediate member 17 is 0.5 mm, the protrusion amount s =
It is about 0.2 mm.

In this way, with the end face protruding, the storage section 1
Fixed orifice 8 and intermediate member 17 housed in 9
Is the body 25 of the three-way solenoid valve 7 with respect to the nozzle holder 5.
Is fastened by the retaining nut 24, the intermediate member 17 is crushed by receiving the tightening force of the retaining nut 24, and is compressed and deformed until the upper end surface 5a of the nozzle holder 5 and the lower end surface 25a of the body 25 come into close contact with each other. (Range of plastic region ) and fixed.

Next, the operation of this embodiment will be described with reference to the time chart shown in FIG. The time chart of FIG. 6 shows a case where pilot injection is performed prior to main injection. FIG. 6A shows the behavior of the outer valve 29 of the three-way solenoid valve 7, and FIG. 6B shows the fixed orifice 8. Position (constant without changing in this embodiment), FIG.
6C shows the pressure fluctuation of the pressure chamber 18, and FIG. 6D shows the behavior of the needle 3.

First, when the coil 26 of the three-way solenoid valve 7 is not energized, the outer valve 29 is returned to the initial position, so that the pressure chamber 18 has the fuel passage 39 and the communication passage 3
4 and the high pressure passage 32 through the oil passage 38 (see FIG. 1). As a result, the pressure chamber 18 is filled with high-pressure fuel, and the internal pressure of the pressure chamber 18 is maintained at the valve closing pressure or higher. As a result, the needle 3 is pushed down via the hydraulic piston 6 and the pressure pin 22, and the seat portion 3a is seated on the seat surface 11, so that fuel is not injected.

After that, when the coil 26 of the three-way solenoid valve 7 is energized, the armature 28 is attracted to the iron core 27 against the biasing force of the spring 37, so that the outer valve 29 moves to the lift position together with the armature 28. To do. As a result, the inner valve 30 disposed inside the outer valve 29 has the oil passage 3 formed in the outer valve 29.
By disconnecting 8, the high pressure passage 32 and the communication passage 34 are disconnected, and at the same time, the low pressure passage 33 and the communication passage 34 are communicated (see FIG. 3).

As a result, the fuel filled in the pressure chamber 18 is discharged to the low pressure passage 33 through the fuel passage 39 and the communication passage 34 of the fixed orifice 8. As a result, as the fuel pressure in the pressure chamber 18 decreases, the needle 3 lifts together with the hydraulic piston 6 and the pressure pin 22, and the seat portion 3a of the needle 3 moves toward the seat surface 11a.
With the further separation, the high pressure fuel is supplied to the suck hole 10 and injected from the injection hole 9.

Here, when the fuel is discharged from the pressure chamber 18, since the orifice (small diameter passage portion 39b) is provided in the fuel passage 39 of the fixed orifice 8, the flow rate of the fuel flowing out from the pressure chamber 18 Can be suppressed. Therefore, the back pressure of the hydraulic piston 6 (fuel pressure in the pressure chamber 18)
Is gradually decreased, the lift operation of the needle 3 is also slowly performed, and the initial injection rate is decreased.

Subsequently, when the energization of the coil 26 of the three-way solenoid valve 7 is stopped, the outer valve 29 is returned to the initial position by the urging force of the spring 37, so that the oil passage 38
The high pressure passage 32 and the communication passage 34 are communicated with each other via the, and the high pressure fuel is filled in the pressure chamber 18 (see FIG. 1).

The fuel passage 39 of the fixed orifice 8 has a funnel portion 39c between the large diameter passage portion 39a and the small diameter passage portion 39b.
The funnel portion 39c is provided with a small diameter passage portion 39c in the flow direction when the fuel flows into the pressure chamber 18.
It has a funnel shape in which the passage cross-sectional area gradually decreases toward b. Therefore, the fuel passage 39 has a larger flow coefficient when the fuel flows into the pressure chamber 18 than when the fuel flows out of the pressure chamber 18, and thus the small-diameter passage when the fuel flows out of the pressure chamber 18. The flow rate of fuel passing through the small diameter passage portion 39b when the fuel flows into the pressure chamber 18 is larger than the flow rate of fuel passing through the portion 39b. As a result, the fuel pressure in the pressure chamber 18 rapidly rises to reach the valve closing pressure,
The needle 3 quickly descends to complete the fuel injection, and the disconnection becomes good.

Even in the pilot injection performed prior to the main injection, the initial injection rate can be reduced and a good injection can be obtained, as in the main injection. Further, in this embodiment, when the fuel is discharged from the pressure chamber 18, the small-diameter passage portion 39 of the fixed orifice 8 is surely used.
Since the fuel flows out after passing b, the initial injection rate of the main injection becomes low or high even if the injection interval between the pilot injection and the main injection is small.
So-called asymmetric injection does not occur.

(Effects of the First Embodiment) In the fuel injection device 1 of this embodiment, the intermediate member 17 is pushed until the upper end surface 5a of the nozzle holder 5 and the lower end surface 25a of the body 25 of the three-way solenoid valve 7 come into close contact with each other. By crushing and compressing and deforming it to the plastic region, the fixed orifice 8 that receives the reaction force from the intermediate member 17 can be tightly fixed to the lower end surface 25a of the body 25. Thus, the fuel introduction passage 21 formed in the nozzle holder 5 and the high pressure passage 32 formed in the body 25 can be liquid-tightly connected to each other without causing fuel leakage. As a result, it is not necessary to control the depth of the storage portion 19 and the total length of the fixed orifice 8 stored in the storage portion 19 with an accuracy of several microns, so that the number of processing steps can be significantly reduced and the cost can be reduced. it is possible.

(Second Embodiment) FIG. 7 is a cross-sectional view of an essential part showing the fixed orifice 8 assembled. In the first embodiment,
Although the intermediate member 17 is stored in the storage portion 19 before the fixed orifice 8, as shown in FIG.
The intermediate member 17 may be housed later.

(Third Embodiment) FIGS. 8 and 9 are cross-sectional views of a main portion showing a fixed orifice 8 assembled. In the first and second embodiments, the storage portion 19 is formed in the nozzle holder 5, but as shown in FIGS. 8 and 9, the storage portion 19 is formed in the body 25 of the three-way solenoid valve 7 and The fixed orifice 8 and the intermediate member 17 may be housed in the housing portion 19. At this time, as for the positional relationship between the fixed orifice 8 and the intermediate member 17, as shown in FIG. 8, the fixed orifice 8 may be stored in the storage portion 19 prior to the intermediate member 17.
As shown in FIG. 9, the intermediate member 17 may be stored in the storage portion 19 before the fixed orifice 8.

(Fourth Embodiment) FIGS. 10 and 11 are cross-sectional views of the essential parts showing the fixed orifice 8 assembled. In this embodiment, the fixed orifice 8 is directly fixed to the storage portion 19 without using the intermediate member 17. Specifically, as shown in FIGS. 10 and 11, screws 40 that are screwed into each other are formed on the inner peripheral surface of the storage portion 19 and the outer peripheral surface of the fixed orifice 8, and the storage portion is formed by screwing them together. The fixed orifice 8 can be fixed at 19. In this case, the storage portion 19 may be formed in the nozzle holder 5 as shown in FIG. 10, or may be formed in the body 25 of the three-way solenoid valve 7 as shown in FIG. However, in the case of the present embodiment, it goes without saying that the total length of the fixed orifice 8 accommodated in the accommodating portion 19 is set shorter than the depth of the accommodating portion 19. In addition to the screw connection described above, the fixed orifice 8 can be press-fitted and fixed into the storage portion 19.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part (at the time of fuel introduction) showing a fixed orifice assembled state.

FIG. 2 is a cross-sectional view showing an assembled state of a fixed orifice and an intermediate member before the three-way solenoid valve is assembled.

FIG. 3 is a cross-sectional view of a main part (at the time of fuel discharge) showing an assembled state of a fixed orifice.

FIG. 4 is an overall sectional view of a fuel injection device.

FIG. 5 is a sectional view of a nozzle portion.

FIG. 6 is a time chart showing the operation of the present embodiment.

FIG. 7 is a sectional view of a main part (second embodiment) showing an assembled state of a fixed orifice.

FIG. 8 is a cross-sectional view of a main part (third embodiment) showing an assembled state of a fixed orifice.

FIG. 9 is a cross-sectional view of a main part (third embodiment) showing an assembled state of a fixed orifice.

FIG. 10 is a cross-sectional view of a main part (fourth embodiment) showing an assembled state of a fixed orifice.

FIG. 11 is a cross-sectional view of a main part (fourth embodiment) showing an assembled state of a fixed orifice.

FIG. 12 is a cross-sectional view of essential parts for explaining the technique of the prior application.

[Explanation of symbols]

1 fuel injector 2 nozzle body (nozzle) 3 needle (nozzle) 5 Nozuruhoru da 6 a hydraulic piston (piston) 7 three-way solenoid valve (path switching exchange means) 8 fixed orifice (throttle member) 9 injection hole 17 middle member 17a intermediate member Round hole (part of fuel passage) 18 Pressure chamber 19 Storage portion (recess) 24 Retaining nut (fastening means) 32 High pressure passage 33 Low pressure passage 34 Communication passage 39 Fuel passage 39b Small diameter passage portion (orifice) 39c Funnel portion (Tapered hole)

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-5-118260 (JP, A) JP-A-5-18333 (JP, A) JP-A 63-9673 (JP, A) JP-A 63- 143377 (JP, A) JP 62-67281 (JP, A) JP 60-36770 (JP, A) JP 59-150975 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 47/00 F02M 61/16

Claims (2)

(57) [Claims] 1. A built-in needle lifts to open a nozzle hole.
A nozzle and holding the nozzle and driving the needle
High pressure fuel is supplied through a nozzle holder that contains a piston for
And its fuel pressure is passed through the piston to the needle
Of the high pressure passage and the high pressure passage and the low pressure passage that act to suppress the lift of the high pressure passage.
Of the fuel passage by selecting one of the low pressure passage and the low pressure passage.
A passage switching means connected to the passage and a fastening hand for fastening the passage switching means to the nozzle holder.
In a fuel injection device including a step, a throttle member that forms the orifice, and a throttle member that is disposed on the pressure chamber side or the counter pressure chamber side of the throttle member.
And an annular intermediate member forming a part of the fuel passage,
Provided with a, whereas if who of the nozzle holder or the passage switching means
A recess is formed in the recess, and the intermediate member and the
A diaphragm member and a tightening force of the fastening means are stored.
That the intermediate member is compressed and deformed to the plastic region.
The fuel injection device is characterized in that the throttle member is fixed . 2. The fuel injection device according to claim 1, wherein the throttle member has a passage cross-sectional area of the orifice which is a counter pressure.
A fuel injection device, characterized in that a taper hole portion is formed which expands in a taper shape toward the chamber side .