JP2007046518A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve introducing fuel into an injection hole by suppressing reduction in a flow velocity, having excellent controllability of a fuel injection amount, and easily installing an injection hole plate. <P>SOLUTION: In this fuel injection valve 1 provided with a valve seat 19 having an opening part 24 for passing fuel from an upstream side, a ball 18 reciprocatingly movable in an axial direction to the valve seat 19, and the injection hole plate 21 in which two or more injection holes 20 which are arranged on the downstream side of the valve seat 19 and into which fuel from the opening part 24 is led to flow are formed on outer peripheral side from the opening part 24, a fuel cavity 25 communicated with the opening part 24 and enlarged in radial direction more than the periphery of the opening part 24 is formed in the downstream side end part of the valve seat 19. A space reducing means for suppressing reduction in the flow velocity of fuel led to flow into the injection hole 20 by reducing a space is arranged in the inside of the fuel cavity 25. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection valve that atomizes and injects fuel.

  In recent years, exhaust gas regulations for internal combustion engines such as automobiles have been strengthened, and there has been a demand for reducing harmful substances emitted. Therefore, combustion is improved by improving atomization of fuel particles injected from the fuel injection valve.

  A conventional fuel injection valve includes a plate member having a plurality of injection holes, a valve seat provided with a valve seat upstream of the injection holes, one cylindrical fuel passage provided in the valve seat, and one cylinder. The fuel cavity disposed between the shape fuel passage and the plate member having a plurality of nozzle holes, and a contact that is supported by the valve seat so as to be able to reciprocate and seat on the valve seat And a valve member that opens and closes the nozzle hole when the contact portion is separated from the valve seat and seated on the valve seat (see, for example, Patent Document 1).

Further, the conventional fuel injector includes a housing, a valve seat (corresponding to the “valve seat” of the present invention), a metering orifice (corresponding to the “injection hole plate” of the present invention), a needle (of the present invention). Corresponding to a “valve”). The housing has an inlet, an outlet, and a longitudinal axis extending through the housing. The valve seat has a passage having a sealing surface and an orifice (corresponding to the “opening” of the present invention), and is disposed in the vicinity of the outlet. The metering orifice has a plurality of metering openings penetrating the outlet and is arranged at the outlet. The needle has a first position where the needle can be moved away from the valve seat and the fuel can flow through the needle, and a second position where the needle is pressed against the valve seat and the fuel cannot flow through the needle. Between the housings so as to reciprocate along the longitudinal axis.
In addition, a control speed channel (corresponding to the “fuel cavity” of the present invention) is formed between the valve seat and the metering orifice, and the control speed channel extends from the orifice to a plurality of metering openings (“ (Corresponding to the “hole”) having a tapered portion extending outward and downward (see, for example, Patent Document 2).

  Further, the conventional nozzle for a fuel injector is provided at one end of each of a plurality of flow paths through which a predetermined amount of pressurized material selectively flows and each of the plurality of flow paths. A plurality of swirl chambers for receiving the swept material and swirling the swept material, each swirl chamber ejecting a swirled pressurized material to atomize the pressurized material (For example, refer to Patent Document 3).

JP 2002-39036 A JP 2002-4983 A JP 2002-98028 A

In the conventional fuel injection valve shown in Patent Document 1, since the volume suddenly increases when the fuel flows into the fuel cavity from the cylindrical fuel passage, the flow rate of the fuel when reaching the injection hole is reduced. For this reason, the fuel having a low flow velocity does not have sufficient energy to cause turbulence, and there is a problem that the fuel is not atomized.
In addition, since the fuel cavity has a large volume, residual fuel remaining in the fuel cavity without being injected from the nozzle hole is discharged outside the nozzle hole when the valve is closed, and the temperature inside the fuel cavity is increased to a high temperature and low pressure. Cavitation occurred when it became. Therefore, there is a problem that the controllability of the fuel injection amount is deteriorated.

  In the conventional fuel injector shown in Patent Document 2, since the control speed channel has a larger volume than the orifice, there is a problem that the controllability of the fuel injection amount is deteriorated as described above.

  In the conventional nozzle for fuel injector shown in Patent Document 3, the flow passage cross-sectional area of the vortex chamber is larger than the flow passage cross-sectional area of the inlet portion of the flow passage. It was getting smaller. Therefore, there is a problem that the fuel is not atomized as described above.

  An object of the present invention is to solve the above-described problems. The object of the present invention is to suppress the reduction of the flow velocity and introduce the fuel into the nozzle hole and to control the fuel injection amount. It is to provide a good fuel injector.

  A fuel injection valve according to the present invention is provided on a downstream side of a valve seat having a valve seat having an opening through which fuel from an upstream side passes, a valve body capable of reciprocating in the axial direction with respect to the valve seat, and An injection hole plate in which a plurality of injection holes into which fuel flows from the opening is formed on the outer peripheral side of the opening, and the downstream end of the valve seat communicates with the opening and the outer periphery of the opening In the fuel injection valve in which the fuel cavity enlarged in the radial direction is formed, a space reducing means for reducing the flow rate of the fuel flowing into the nozzle hole by reducing the space is provided inside the fuel cavity. It is provided.

According to the fuel injection valve of the present invention, since the space reducing means for reducing the flow rate of the fuel flowing into the nozzle hole by reducing the space is provided inside the fuel cavity, the reduction of the flow rate is suppressed. Thus, fuel can be introduced into the nozzle hole.
Further, since the space reducing means reduces the volume inside the fuel cavity, the fuel remaining in the fuel cavity can be reduced, the occurrence of cavitation can be suppressed, and the controllability of the fuel injection amount can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a cross-sectional view showing a fuel injection valve 1 according to Embodiment 1 of the present invention, FIG. 2 is an enlarged view of a main part of the valve device 4 shown in FIG. 1, and FIG. 3 is a valve device 4 of FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV of the valve device 4 of FIG. 3.
In the figure, the fuel injection valve 1 has a resin housing 3, a valve device 4 provided at the downstream end of the housing 3, and a solenoid device 5 that drives the valve device 4 by electromagnetic attraction. ing.

  In the solenoid device 5, a filter 2 that removes foreign matters in the fuel is provided inside a fixed iron core 6 that is a fixed side of the magnetic circuit. On the outer peripheral side of the fixed iron core 6, an electromagnetic coil 7 that generates magnetic flux is provided. The electromagnetic coil 7 includes a resin bobbin 8, a coil 9 wound around the outer periphery of the bobbin 8, and a terminal 10 for connection to the outside. A metal plate 11 constituting a magnetic circuit is provided on the outer peripheral side of the electromagnetic coil 7. One end of the metal plate 11 is welded to the fixed iron core 6 and the other end is welded to a hollow cylindrical magnetic pipe 12 that also forms a magnetic circuit. Inside the magnetic pipe 12, a movable iron core 13, which is the movable side of the magnetic circuit, is provided so as to be slidable in the axial direction. Between the fixed iron core 6 and the magnetic pipe 12, a non-magnetic pipe 14 constituting a portion through which the magnetic flux of the magnetic circuit does not pass is fixed.

One end of the movable iron core 13 is welded with a needle pipe 15 having a C-shaped cross section when cut along a plane perpendicular to the axis, and having a flow hole 15a and a flow gap 15b through which the fuel passes. The upstream side of the needle pipe 15 is in contact with a compression spring 16 that presses the needle pipe 15 to the downstream side. An adjuster 17 that adjusts the load of the compression spring 16 is fixed inside the fixed iron core 6.
Here, the fixed iron core 6, the electromagnetic coil 7, and the metal plate 11 are integrally formed inside the housing 3.

  In the valve device 4, a ball 18, which is a valve body reciprocated by the solenoid device 5, is welded to the lower end surface of the needle pipe 15. Inside the magnetic pipe 12, a valve seat 19 having an opening 24 through which fuel from the upstream side passes is provided. On the downstream side of the valve seat 19, an injection hole plate 21 in which an injection hole 20 for injecting fuel that has passed through the valve seat 19 to the outside is formed is welded.

The valve seat 19 includes a seat portion 22 that is a surface in contact with the ball 18, a guide portion 23 that guides the reciprocating movement of the ball 18 in the axial direction, an opening portion 24 through which fuel from the upstream side passes, and an opening portion And a fuel cavity 25 that communicates with 24 and expands in the radial direction from the outer periphery of the opening 24.
Further, the outer peripheral surface of the ball 18 is formed by cutting the sphere so as to be substantially pentagonal along the axial direction, and the fuel passes through the gap between the guide portion 23 and the ball 18.

  The nozzle hole plate 21 has a plurality of nozzle holes 20 each having a center in a center circle which is a circle having the same radius centered on the center point when the intersection point with the axis of the ball 18 is the center point. It is provided in the circumferential direction. Each nozzle hole 20 is penetrated in the plate | board thickness direction by the arbitrary angles according to the injection direction of the fuel, respectively.

Here, the fuel cavity 25 is formed at the downstream end of the valve seat 19. Inside the fuel cavity 25, a space reducing portion (space reducing means) 19 a having a guide surface 26 a that guides the flow direction of the fuel in the direction of each nozzle hole 20 and defines the fuel flow path 26 is provided in the valve seat 19. It is integrally formed at the downstream end, and the space inside the fuel cavity 25 is reduced.
The guide surface 26a is a flat surface, and each fuel channel 26 has the same channel cross-sectional area at the inlet and the channel cross-sectional area in the vicinity of the nozzle hole 20, and from the inlet to the nozzle hole 20. The length in the axial direction is not changed.

Hereinafter, the operation of the fuel injection valve 1 configured as described above will be described.
First, fuel is introduced into the main body of the fuel injection valve 1 through a derivative pipe (not shown), passes through the filter 2, the adjuster 17, the compression spring 16, and the flow holes 15a and 15b of the needle pipe 15, and the valve. It is stored in the device 4.

Subsequently, when an operation signal is sent from the engine control device (not shown) to the fuel injection valve 1, a current is passed through the coil 9 of the solenoid device 5 via the terminal 10, and a magnetic flux is generated in the coil 9. . The generated magnetic flux passes through a magnetic circuit composed of the fixed iron core 6, the metal plate 11, the magnetic pipe 12, and the movable iron core 13, and the movable iron core 13 is moved by the electromagnetic attraction force generated along with the generation of the magnetic flux. It is attracted toward the fixed iron core 6 against the compressive force.
When the movable iron core 13 is sucked to the fixed iron core 6 side, the ball 18 connected to the movable iron core 13 via the needle pipe 15 is also moved to the fixed iron core 6 side, and the seat portion 22 of the valve seat 19 and the ball 18 are moved. A gap is formed between them.

When a gap is formed between the ball 18 and the seat portion 22, the fuel accumulated in the valve device 4 is introduced into the fuel cavity 25 through the opening 24 from this gap.
Here, the flow path cross-sectional area at the inlet of the fuel flow path 26 and the flow path cross-sectional area in the vicinity of the injection hole 20 are formed to have the same size, so that the fuel introduced into the fuel cavity 25 has a reduced flow rate. Is suppressed and introduced into the nozzle hole 20 and agitated with the air inside the nozzle hole 20 to be atomized.

  Next, when an operation stop signal is sent to the fuel injection valve 1 from the engine control device, the energization of the current to the coil 9 of the solenoid device 5 is stopped, and the electromagnetic attractive force is also lost as the magnetic flux is lost. With the disappearance of the electromagnetic attractive force, the ball 18 is pressed downstream by the compression spring 16, and the gap between the ball 18 and the seat portion 22 is closed.

  According to the fuel injection valve 1 according to Embodiment 1 of the present invention, the fuel flow path 26 is defined by the guide surface 26a, the flow path cross-sectional area of the inlet portion of the fuel flow path 26, and the flow path in the vicinity of the injection hole 20 Since the cross-sectional area is formed in the same size, the fuel introduced into the fuel cavity 25 reaches the injection hole 20 with the reduction of the flow velocity suppressed, and can promote atomization.

  Further, since the volume of the fuel cavity 25 is reduced by the space reducing portion 19a, the fuel remaining in the fuel cavity 25 can be reduced, the occurrence of cavitation can be suppressed, and the controllability of the fuel injection amount can be improved. Can do.

Further, in the above-mentioned Cited Document 2, since the control speed channel is tapered toward the outer peripheral side, the length in the axial direction is reduced to reduce the cross-sectional area of the fuel flow path. Due to the positional deviation when assembled to the valve seat, the length of the control speed channel in the axial direction differs, and the cross-sectional area in the vicinity of the metering opening varies. Therefore, the directivity of the fuel injected from each metering opening is deteriorated, and there is a problem that the shape of the fuel varies.
Here, according to the fuel injection valve 1 according to Embodiment 1 of the present invention, each fuel flow path 26 has the same cross-sectional area at the inlet and the cross-sectional area near the injection hole 20. In addition, since the axial length from the inlet portion to the nozzle hole 20 is not changed, the axis of the fuel flow path 26 can be obtained even when a deviation occurs when the nozzle hole plate 21 is assembled to the valve seat 19. There is no difference in the length of the direction, the nozzle hole plate 21 can be easily assembled, and the directivity of the fuel injected from the nozzle hole 20 can be prevented from deteriorating and variations in the shape of the fuel can be prevented. .

  In the first embodiment, the space reducing portion 19a has been described as being a part of the valve seat 19. However, the space reducing portion is not limited to this, and the space reducing portion is, as shown in FIG. A space reduction member (space reduction means) 29 provided between the valve seat 28 and the injection hole plate 21 as shown in FIG. 6 may be formed integrally on the upstream side of the injection hole plate 27. Also good. In these cases, the same effects as those of the first embodiment can be obtained.

Embodiment 2. FIG.
FIG. 7 is a cross-sectional view of the main part showing the valve device 4 of the fuel injection valve 1A according to Embodiment 2 of the present invention.
In FIG. 7, the guide surface 30 a defining the fuel flow path 30 is a flat surface, and each fuel flow path 30 has a flow path cross-sectional area at the inlet portion larger than the flow path cross-sectional area near the injection hole 20. Is formed.
Other configurations are the same as those in the first embodiment, and the description thereof is omitted.

Hereinafter, the operation of the fuel injection valve 1A having the above configuration will be described. Note that the description of the same operation as in the first embodiment is omitted.
When a gap is formed between the ball 18 and the seat portion 22, the fuel accumulated in the valve device 4 is introduced into the fuel cavity 25 through the opening 24 from this gap.
Here, since the flow path cross-sectional area of the inlet portion of the fuel flow path 30 is formed larger than the flow path cross-sectional area in the vicinity of the nozzle hole 20, the fuel introduced into the fuel cavity 25 The flow velocity rises from the inlet and is introduced into the nozzle hole 20 and is agitated with the air inside the nozzle hole 20 to be atomized.

  In the fuel injection valve 1A according to Embodiment 2 of the present invention, the flow passage cross-sectional area of the inlet portion of the fuel flow passage 30 is formed larger than the flow passage cross-sectional area in the vicinity of the injection hole 20, so that the fuel The fuel introduced into the cavity 25 has a flow velocity that is higher than that at the inlet of the fuel flow path 30 and is introduced into the nozzle hole 20, thereby further promoting atomization.

Embodiment 3 FIG.
FIG. 8 is a cross-sectional view of the main part showing the valve device 4 of the fuel injection valve 1B according to Embodiment 3 of the present invention.
In FIG. 8, the guide surface 31 a that defines the fuel flow path 31 is configured by a curved surface having a curvature that protrudes toward the inside of the fuel flow path 31, and each fuel flow path 31 has a flow path cross-sectional area of the inlet portion. However, it is formed larger than the cross-sectional area of the flow path near the nozzle hole 20.
Other configurations are the same as those in the second embodiment, and the description thereof is omitted.

Hereinafter, the operation of the fuel injection valve 1B having the above configuration will be described. The description of the same operation as that of the second embodiment is omitted.
When a gap is formed between the ball 18 and the seat portion 22, the fuel accumulated in the valve device 4 is introduced into the fuel cavity 25 through the opening 24 from this gap.
Here, since the cross-sectional area of the inlet of the fuel flow path 31 is formed larger than the cross-sectional area of the flow path near the injection hole 20, the fuel introduced into the fuel cavity 25 is The flow velocity rises from the inlet and is introduced into the nozzle hole 20 and is agitated with the air inside the nozzle hole 20 to be atomized.

  According to the fuel injection valve 1B according to Embodiment 3 of the present invention, the guide surface 31a is configured by a curved surface protruding toward the inside of the fuel flow path 31, so that the guide surface 31a is a flat surface. Since the volume of the fuel cavity 25 can be further reduced, the flow rate of the fuel introduced into the nozzle hole 20 can be increased from the inlet portion of the fuel flow path 31, and the residual fuel can be further reduced. it can.

Embodiment 4 FIG.
FIG. 9 is a cross-sectional view of the main part showing the valve device 4 of the fuel injection valve 1C according to Embodiment 4 of the present invention.
In FIG. 9, the guide surface 32 a that defines the fuel flow path 32 is configured by a curved surface having a curvature protruding toward the outside of the fuel flow path 32, and each fuel flow path 32 extends from the outside to the flow path of the inlet portion. The cross-sectional area is formed larger than the cross-sectional area of the flow path near the nozzle hole 20.
Other configurations are the same as those in the second embodiment, and the description thereof is omitted.

Hereinafter, the operation of the fuel injection valve 1C having the above configuration will be described. The description of the same operation as that of the second embodiment is omitted.
When a gap is formed between the ball 18 and the seat portion 22, the fuel accumulated in the valve device 4 is introduced into the fuel cavity 25 through the opening 24 from this gap.
Here, the guide surface 32 a is configured by a curved surface having a curvature protruding toward the outside of the fuel flow path 32, and the flow path cross-sectional area of the inlet portion of the fuel flow path 32 is larger than the flow path cross-sectional area in the vicinity of the injection hole 20. Therefore, the fuel introduced into the fuel cavity 25 is introduced into the nozzle hole 20 with the flow velocity rising from the outside of the fuel channel 32 toward the inside from the inlet of the fuel channel 32, It is atomized by stirring with the air inside the nozzle hole 20.

  According to the fuel injection valve 1C according to the fourth embodiment of the present invention, the guide surface 32a is configured by a curved surface protruding toward the outside of the fuel flow path 32, so that the fuel is injected so as to wrap around from the outside to the inside. Since it is introduced into the hole 20, the radial force of the fuel introduced into the fuel cavity 25 is weakened, and the width of the fuel spray injected from the injection hole 20 can be reduced.

Embodiment 5. FIG.
FIG. 10 is a cross-sectional view of a main part showing a valve device 4 of a fuel injection valve 1D according to Embodiment 5 of the present invention.
In FIG. 10, the guide surface 33 a that defines the fuel flow path 33 is configured by a curved surface having a curvature that protrudes toward the inside of the fuel flow path 33, and each fuel flow path 33 has a cross-sectional area of the inlet portion. However, it is formed larger than the cross-sectional area of the flow path near the nozzle hole 20. Further, the flow passage cross-sectional area of each fuel flow passage 33 is formed to be larger than the flow passage cross-sectional area near the injection hole 20 on the downstream side of the injection hole 20.
Other configurations are the same as those in the second embodiment, and the description thereof is omitted.

Hereinafter, the operation of the fuel injection valve 1D having the above configuration will be described. The description of the same operation as that of the second embodiment is omitted.
When a gap is formed between the ball 18 and the seat portion 22, the fuel accumulated in the valve device 4 is introduced into the fuel cavity 25 through the opening 24 from this gap.
Here, since the flow path cross-sectional area of the inlet portion of the fuel flow path 33 is formed larger than the flow path cross-sectional area in the vicinity of the injection hole 20, the fuel introduced into the fuel cavity 25 flows through the fuel flow path 33. The flow velocity rises from the inlet and is introduced into the nozzle hole 20 and is agitated with the air inside the nozzle hole 20 to be atomized.

  Further, since the flow passage cross-sectional area of each fuel flow passage 33 is formed to be larger than the flow passage cross-sectional area in the vicinity of the injection hole 20 on the downstream side of the injection hole 20, it is not introduced into the injection hole 20. The fuel is reflected while having a force perpendicular to the axial direction of the fuel injection valve 1D on the downstream side of the injection hole 20, and the cross-sectional area is narrowed again toward the injection hole 20, whereby the fuel flow path. The flow velocity rises from the inlet portion 33 and is introduced into the nozzle hole 20, and is agitated with the air inside the nozzle hole 20 to be atomized.

In the case of the thing of FIG. 8, when the flow velocity of the fuel which was not introduce | transduced into the nozzle hole 20 becomes large, when a fuel reflects in the downstream of the nozzle hole 20, it will become a vertical flow, and a dispersion | variation will arise in the fuel flow direction.
However, according to the fuel injection valve 1D according to the fifth embodiment of the present invention, the guide surface 33a is a curved surface that protrudes toward the inside of the fuel flow path 33 and is downstream of the nozzle hole 20, and the flow path is cut off. Since the area is formed to be larger than the cross-sectional area of the flow path in the vicinity of the nozzle hole 20, the flow direction or flow rate of the fuel that has not been introduced into the nozzle hole 20 can be controlled.

Embodiment 6 FIG.
In the method of Patent Document 3 described above, in the method of generating turbulence in the vicinity of the nozzle hole 20, the spray is greatly spread due to the centrifugal force of the fluid in the nozzle hole 20, thereby deteriorating the directivity of the spray. However, there was also a problem of causing deterioration of combustibility.

FIG. 11 is a cross-sectional view of an essential part showing a valve device 4 of a fuel injection valve 1E according to Embodiment 6 of the present invention.
In FIG. 11, the guide surface 34 a that defines the fuel flow path 34 is formed of a curved surface having a curvature, and the downstream side of the fuel flow path 34 has a radial direction in which the fuel flow direction is the solid arrow direction. A direction changing portion 35 is formed for changing from the peripheral direction to the circumferential direction which is the direction of the dotted arrow.
In addition, each fuel flow path 34 is formed such that the flow path cross-sectional area at the inlet and the flow path cross-sectional area near the nozzle hole 20 are the same size.

Hereinafter, the operation of the fuel injection valve 1E having the above configuration will be described. Note that the description of the same operation as in the first embodiment is omitted.
When a gap is formed between the ball 18 and the seat portion 22, the fuel accumulated in the valve device 4 is introduced into the fuel cavity 25 through the opening 24 from this gap.
Here, the direction of the fuel introduced into the fuel cavity 25 is changed from the radial direction to the circumferential direction by the direction changing portion 35 and introduced into the nozzle hole 20, and is agitated with the air inside the nozzle hole 20 to be atomized. The

  According to the fuel injection valve 1E according to Embodiment 6 of the present invention, the downstream side of the fuel flow path 34 is provided with the direction changing portion 35 that changes the fuel flow direction from the radial direction to the circumferential direction. The radial force of the fuel introduced into the fuel cavity 25 can be changed in the circumferential direction, and the width of the fuel spray injected from the injection hole 20 can be reduced.

  In the sixth embodiment, the flow path cross-sectional area at the inlet of the fuel flow path 34 and the flow path cross-sectional area in the vicinity of the injection hole 20 have been described as being the same size, but of course the present invention is limited to this. Instead, the channel cross-sectional area of the inlet portion may be formed larger than the channel cross-sectional area near the nozzle hole 20. In this case, since the flow rate of the fuel introduced into the nozzle hole 20 can be made faster than the inlet portion of the fuel flow path 34, the fuel can be further atomized.

It is sectional drawing which shows the fuel injection valve which concerns on Embodiment 1 of this invention. It is a principal part enlarged view of the valve apparatus shown in FIG. It is arrow sectional drawing along the III-III line of the valve apparatus of FIG. It is arrow sectional drawing along the IV-IV line of the valve apparatus of FIG. It is another principal part enlarged view of the valve apparatus shown in FIG. It is another principal part enlarged view of the valve apparatus shown in FIG. It is principal part sectional drawing which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 2 of this invention. It is principal part sectional drawing which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 3 of this invention. It is principal part sectional drawing which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 4 of this invention. It is principal part sectional drawing which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 5 of this invention. It is principal part sectional drawing which shows the valve apparatus of the fuel injection valve which concerns on Embodiment 6 of this invention.

Explanation of symbols

  1, 1A to 1E Fuel injection valve, 18 ball (valve element), 19, 28 valve seat, 19a space reduction part (space reduction means), 20 injection hole, 21, 27 injection hole plate, 24 opening part, 25 fuel cavity , 26, 30 to 34 Fuel flow path, 26a, 30a to 34a Guide surface, 29 Spatial reduction member (space reduction means), 35 direction change part.

Claims (9)

A valve seat having an opening through which fuel from the upstream side passes;
A valve body capable of reciprocating in the axial direction with respect to the valve seat;
An injection hole plate provided on the downstream side of the valve seat, and a plurality of injection holes into which the fuel flows from the opening is formed on the outer peripheral side of the opening;
In the fuel injection valve in which a fuel cavity is formed at the downstream end of the valve seat and communicates with the opening and expands in a radial direction from the outer periphery of the opening.
A fuel injection valve characterized in that a space reducing means for reducing the flow velocity of the fuel flowing into the nozzle hole by reducing the space is provided inside the fuel cavity.   The fuel injection valve according to claim 1, wherein the space reducing means is a part of the valve seat.   The fuel injection valve according to claim 1, wherein the space reducing means is a part of the injection hole plate.   The fuel injection valve according to claim 1, wherein the space reducing means is a space reducing member provided between the nozzle hole plate and the valve seat.   The space reduction means has a guide surface that defines a plurality of fuel flow paths and guides the flow direction of the fuel in the directions of the plurality of nozzle holes, and each of the plurality of fuel flow paths. The flow path cross-sectional area at the inlet of the fuel flow path and the flow path cross-sectional area near the nozzle hole are formed to have the same size. The fuel injection valve according to Item 1.   The space reduction means has a guide surface that defines a plurality of fuel flow paths and guides the flow direction of the fuel in the directions of the plurality of nozzle holes, and each of the plurality of fuel flow paths. The flow path cross-sectional area of the inlet portion of the fuel flow path is formed larger than the flow path cross-sectional area in the vicinity of the nozzle hole, according to any one of claims 1 to 4. The fuel injection valve as described.   The fuel injection valve according to claim 5, wherein the guide surface is a surface having a curvature.   The flow path cross-sectional area on the downstream side of the nozzle hole is formed to be larger than the flow path cross-sectional area in the vicinity of the nozzle hole, according to any one of claims 5 to 7. Fuel injection valve.   The direction change part which changes the flow direction of the said fuel from the radial direction to the circumferential direction is formed in the downstream of the said fuel flow path, The any one of Claim 5 to 7 characterized by the above-mentioned. The fuel injection valve described in 1.

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