JP4757947B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve used in an engine, and more particularly to a fuel injection valve provided with an injection hole plate provided on the downstream side of a valve seat and having a convex portion at the center.

FIG. 12 is a cross-sectional view showing a main part of a conventional fuel injection valve.
In this conventional fuel injection valve, the ball 13 at the tip of the valve body is separated from the valve seat 10, so that the fuel flows from the plurality of injection holes 12 </ b> A of the injection hole plate 11 </ b> A joined to the lower end surface of the valve seat 10. It is injected into the engine intake pipe.
This nozzle hole plate 11A has a convex portion 11d that is substantially axisymmetric with respect to the valve seat shaft 10c and has a circular arc-shaped cross section protruding downstream, and a plurality of convex portions 11d are formed on the convex portion 11d. A nozzle hole 12A is formed (see, for example, Patent Documents 1 and 2).

JP 2001-27169 A JP 2006-207419 A

  In this fuel injection valve, since a plurality of injection holes 12A are formed in the projection 11d of the injection hole plate 11A, when the injection hole plate 11A is welded to the valve seat 10 by the welding part 11a, the welding part 11a is cooled. Since it shrinks when it hardens, it is pulled radially in the direction (arrow X direction) on the inner diameter side of the welded portion 11a of the nozzle hole plate 11A and deformed in a direction in which the height of the convex portion 11d becomes smaller. Residual stress generated in is relaxed. Therefore, compared with the case where the injection hole plate 11A does not have the convex portion 11d, the decrease in the roundness of the conical valve seat portion 10a due to the welding of the injection hole plate 11A is reduced, and the deterioration of the valve oil tightness is suppressed. effective.

  However, in this fuel injection valve, since the injection hole 12A is arranged in the convex portion 11d, the fuel injection direction changes to the injection angle θ and the arrow Y direction due to deformation of the convex portion 11d after welding, and welding is performed. There is also a problem that the injection direction of the nozzle hole 12A varies due to variations in the number of nozzles.

  An object of the present invention is to solve such a problem. After the injection hole plate is welded to the valve seat, the fuel injection direction does not change even if the convex portion is deformed, and due to welding variations. It is an object of the present invention to obtain a fuel injection valve that can suppress deterioration in valve oil tightness after welding without variation in the fuel injection direction.

The fuel injection valve according to the present invention has a valve body for opening and closing the valve seat, and by operating the valve body in response to an operation signal from the control device, the fuel passes through the clearance between the valve body and the valve seat. in the fuel injection valve to be injected from the plurality was injection hole in the injection hole plate provided in the valve seat downstream side, the injection hole plate, the protrusion protruding to the downstream side in the valve tip and flat ascending And an extension of the valve seat portion of the valve seat intersects a radially outer nozzle hole plate of the convex part, and an inlet part of the nozzle hole is radially outer than the convex part and the valve seat Directly above the nozzle hole, which is disposed radially inward from the inner wall of the valve seat opening, which is the minimum inner diameter of the nozzle hole, and represented by the distance between the center of the inlet portion of the nozzle hole and the valve seat axial direction of the valve body tip The height h and the inlet diameter d of the nozzle hole have a relationship of h ≦ 1.5d in the valve open state.

  According to the fuel injection valve of the present invention, after the injection hole plate is welded to the valve seat, the fuel injection direction does not change even if the convex portion is deformed, and there is no variation in the fuel injection direction due to welding variations. Deterioration of valve oil tightness after welding can be suppressed.

It is sectional drawing which shows the fuel injection valve of the reference example 1 of this invention. It is an enlarged view which shows the front-end | tip part of the fuel injection valve of FIG. It is a figure when the injection hole plate is seen along the cross section which shows the principal part of the fuel injection valve of Embodiment 1 of this invention, and the arrow D. It is an arrow enlarged view of the cross section along the EE line of FIG. 3A. It is an arrow enlarged view of the cross section along the FF line of FIG. 3A. It is a characteristic view which shows the relationship between (h / d) and the spray average particle diameter in the fuel injection valve of FIG. 3A. It is a figure when the injection hole plate is seen along the cross section which shows the principal part of the fuel injection valve of Embodiment 2 of this invention, and the arrow G. It is a figure when the injection hole plate is seen along the cross section which shows the principal part of the fuel injection valve of Embodiment 3 of this invention, and the arrow J. (A) is a cross-sectional view taken along line KK in FIG. 6A, (b) is a cross-sectional view taken along line LL in FIG. 6A, and (c) is taken along line MM in FIG. 6A. FIG. It is sectional drawing which shows the principal part of the fuel injection valve of Embodiment 4 of this invention. It is a characteristic view which shows the relationship between (r / R) and the spray average particle diameter in the fuel injection valve of Embodiment 4 of this invention. It is sectional drawing which shows the principal part of the fuel injection valve of Embodiment 5 of this invention. It is a characteristic view which shows the relationship between ((alpha)-(beta)) and the spray average particle diameter in the fuel injection valve of Embodiment 5 of this invention. It is a characteristic view which shows the relationship between the cavity volume and spray average particle diameter in the fuel injection valve of Embodiment 6 of this invention. It is principal part sectional drawing which shows the conventional fuel injection valve. FIG. 13 is a cross-sectional view showing the fuel injection valve of FIG. 12 and a view of the injection hole plate along the arrow A. FIG. 13B is an enlarged view of a cross section taken along line BB in FIG. 13A. FIG. 13B is an enlarged view of a cross section taken along line CC in FIG. 13A.

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.
Reference Example 1
FIG. 1 is a cross-sectional view showing a fuel injection valve 1 of Reference Example 1 of the present invention, and FIG. 2 is an enlarged view showing a tip portion of the fuel injection valve 1 of FIG.
The fuel injection valve 1 includes a solenoid device 2, a valve device 7 that operates by driving the solenoid device 2, and a case 50 that covers the solenoid device 2 and the valve device 7.
The solenoid device 2 includes a housing 3 which is a yoke portion of a magnetic circuit, a cylindrical core 4 provided inside the housing 3, a coil 5 surrounding the core 4, and a core 4 on the downstream side of the core 4. A cylindrical armature 6 provided so as to be able to come into contact with and separate from the lower end surface 4a, a compression spring 14 housed in the core 4, and a connector 51 which is electrically connected to the coil 5 and whose tip is exposed to the outside. And.
The valve device 7 includes a cylindrical valve body 8 having a ball 13 at the tip, a cylindrical valve body 9 that is press-fitted and welded to the lower outer peripheral side of the core 4, and a lower end portion of the valve body 9. A press-fitted valve seat 10 and an injection hole plate 11 surface-welded to the downstream end face of the valve seat 10 by welding at a welded portion 11a are provided. The valve seat 10 integrated with the nozzle hole plate 11 by the welded part 11a is press-fitted into the inside from the downstream end of the valve body 9, and then the welded part 11b at the outer peripheral edge of the nozzle hole plate 11 bent. And is connected to the valve body 9 by welding.

The nozzle hole plate 11 is formed with a plurality of nozzle holes 12 penetrating in the plate thickness direction at intervals along the circumferential direction.
As shown in FIG. 2, the nozzle hole plate 11 has a convex part 11 d that is substantially axially symmetric with respect to the valve seat shaft 10 c and has an arcuate cross section at the center of the nozzle hole plate 11. The welded portion 11a of the valve seat 10 and the nozzle hole plate 11 is also substantially axially symmetric with respect to the valve seat shaft 10c, and the inlet portion 12a of the nozzle hole 12 is radially outward from the convex portion 11d and the valve seat. The valve seat opening inner wall 10b, which is the minimum inner diameter of the valve seat 10b, is disposed radially inward. The nozzle hole arrangement surface 11e on which the nozzle holes 12 are arranged is on the same plane as the upper surface 11c on the upstream side of the nozzle hole plate 11 having the welded portion 11a.
In addition, although the convex part 11d protrudes in the downstream direction in this reference example 1 , it may protrude in the upstream direction. Further, the injection hole arrangement surface 11e and the upper surface 11c on the upstream side of the injection hole plate 11 are flat surfaces, but may be conical surfaces.

Next, the operation of the fuel injection valve 1 configured as described above will be described.
When an operation signal is sent from the engine control device to the drive circuit of the fuel injection valve, a current is passed through the coil 5 through the connector 51, and a magnetic flux is applied to the magnetic circuit composed of the armature 6, the core 4, the housing 3, and the valve body 9. Will occur. As a result, the armature 6 is attracted to the core 4 side against the elastic force of the compression spring 14, the upper end surface 6 a of the armature 6 abuts on the lower end surface 4 a of the core 4, and the valve body that is integral with the armature 6. 8, a clearance is formed away from the conical valve seat portion 10a.
Simultaneously with the formation of the clearance, the fuel in the fuel passage 52 passes through the chamfered portion 13a of the ball 13 provided at the tip of the valve body 8 and the clearance, and passes through the clearance from the injection hole 12 to the engine intake pipe (not shown). Is injected into.

Next, when an operation stop signal is sent from the engine control device to the drive circuit of the fuel injection valve 1, the energization of the current of the coil 5 from the connector 51 is stopped, the magnetic flux in the magnetic circuit is reduced, and the valve body Due to the elastic force of the compression spring 14 pressing the 8 in the valve closing direction, the clearance between the valve body 8 and the valve seat portion 10a is closed, and fuel injection ends.
During the opening / closing valve operation of the valve body 8, the valve body 8 slides with the guide portion 9a protruding inward in the radial direction of the valve body 9, and the guide portion 13b of the ball 13 of the valve body 8 Slide with the moving part 10e. The guide 13b is a means for regulating the non-coaxiality (swing) in the radial direction of the valve body 8 with respect to the valve seat sliding portion 10e. Accordingly, the clearance is preferably set as small as possible, and is set to 10 μm or less (one-side clearance of 5 μm or less) in order to keep the durable wear of the valve body 8 within an allowable limit.

According to the fuel injection valve 1 according to this reference example, as can be seen from FIG. 2, the nozzle hole 12 is disposed radially outside the convex portion 11d and radially inward from the valve seat opening inner wall 10b, and the nozzle hole. The arrangement surface 11e is flush with the upper surface 11c having the welded portion 11a. Accordingly, when the injection hole plate 11 is welded to the valve seat 10, even if the convex portion 11d is deformed due to contraction when the welded portion 11a is cooled and solidified, the fuel injection direction does not change, and the injection direction due to welding variation The deterioration of the valve oil tightness after welding is suppressed.

Further, due to assembly variations in manufacturing, the central axis of the nozzle hole plate 11 and the valve seat shaft 10c of the valve seat 10 may be welded without matching. In this case, the tensile stress in the radial direction (arrow X direction) with respect to the nozzle hole plate 11 after welding is uneven, and the stress that is relieved by the deformation of the convex portion 11d is also uneven in the radial direction, so that the valve seat portion 10a. There is a concern that the effect of alleviating the decrease in roundness cannot be sufficiently obtained.
On the other hand, according to the fuel injection valve 1 of the first reference example , since the convex portion 11d has an arc-shaped cross section, the misalignment of the injection hole plate 11 with respect to the valve seat 10 with respect to the conical or cylindrical convex portion. The influence of can be suppressed small.

Further, in the fuel injection valve described in Japanese Patent Application Laid-Open No. 2002-4983 (Patent Document 3), a radially extending fuel passage and an injection hole inlet portion are provided on the downstream side of the convex portion provided in the central portion of the injection hole plate. Yes. In this case, when the positional deviation of the nozzle hole plate occurs, there is a problem that the fuel flow is biased due to the deviation between the central axis of the convex portion and the valve seat shaft, and the flow rate and spray vary.
On the other hand, in the fuel injection valve of the reference example 1 , since the injection hole inlet portion 12a is disposed radially inward from the valve seat opening inner wall 10b, the convex portion 11d is formed in the fuel flow from the valve seat portion 10a. Since it is on the downstream side of the inlet portion 12a of the nozzle hole 12, the influence of the positional deviation of the nozzle hole plate 11 on the flow rate and spraying is smaller than that of the structure shown in Patent Document 3.

Embodiment 1 FIG .
3A is a cross-sectional view showing the main part of the fuel injection valve 1 according to Embodiment 1 of the present invention, and a view when the nozzle hole plate 11 is viewed along the arrow D. FIG.
In the fuel injection valve 1 according to the first embodiment, the arc-shaped convex portion 11d protruding downstream of the nozzle hole plate 11 is substantially parallel to the curved surface of the ball 13 that is the tip of the valve body, and the valve seat. The sheet surface extension 10d of the portion 10a intersects the injection hole arrangement surface 11e in which the injection holes 12 on the radially outer side of the projection 11d are formed. Further, the inlet 12a of the injection hole 12 is disposed on the outer side in the radial direction from the convex portion 11d and on the inner side in the radial direction from the inner wall 10b of the valve seat opening. The relationship between the height h immediately above the nozzle hole and the inlet diameter d of the nozzle hole 12 expressed by the distance between the center of the inlet 12a of the nozzle hole 12 and the valve seat axis 10c direction of the ball 13 is the valve opening. In the state, h ≦ 1.5d.
Other configurations are the same as those in Reference Example 1 .

In the fuel injection valve described in Patent Document 2 shown in FIG. 12, as shown in FIG. 13A, the main flow 16a of the fuel that has passed through the valve seat portion 10a when the valve is opened is on the convex portion 11d side of the injection hole 12A. The nozzle hole 12A is annularly arranged so as to directly collide with the inner wall surface.
In the case of the fuel injection valve, the fuel that has passed between the adjacent nozzle holes 12A collides with the fuel that has flowed oppositely at the center of the nozzle hole plate 11A, and the U-turn flow 16b flows to the nozzle hole 12A. Although the direction changes, it is important how to handle this radial U-turn flow 16b.
In the fuel injection valve described in Patent Document 2, the injection hole 12A is arranged in the convex portion 11d protruding to the downstream side substantially parallel to the ball 13, and the injection hole plate 11A and the ball 13 through which the fuel passes are arranged. The distance between them is uniformly narrower from the upstream to the injection hole 12A as compared with the first embodiment . Therefore, the U-turn flow 16b and the main flow 16a flowing directly toward the injection hole 12A collide head-on at the inlet 12a of the injection hole 12A, and the main flow 16a of the injection hole 12A of the main flow 16a aimed by the above-mentioned Patent Document 2 is aimed. The direct collision with the inner wall surface is just after valve opening, and during the fully open state, the fuel spray does not collide with the inner wall surface of the injection hole 12A, so that the fuel spray becomes streaky, as shown in FIGS. 13B and 13C. A fine atomization effect cannot be obtained.

On the other hand, in the fuel injection valve of the first embodiment , as shown in FIG. 3A, the seat surface extension 10d intersects the injection hole arrangement surface 11e on the radially outer side of the convex portion 11d, and the seat surface extension The main flow 16a of the fuel flowing along 10d lands on the nozzle hole arrangement surface 11e. Further, the cavity height, which is the distance from the upper surface 11c on the upstream side of the nozzle hole plate 11 to the ball 13 in the direction of the valve seat shaft 10c, is substantially from the center of the nozzle hole plate 11 to the outermost diameter part 11f of the convex part 11d. Although it is constant, it increases in the region of the injection hole arrangement surface 11e from the convex outermost diameter portion 11f to the valve seat opening inner wall 10b.
Therefore, the main flow 16a of the fuel at the time of valve opening can sink under the U-turn flow 16b radiated along the shape of the convex portion 11d from the outermost diameter portion 11f, and the fuel main flow 16a and the U-turn flow 16b Are prevented, and the deceleration of the fuel main flow 16a by the U-turn flow 16b is suppressed.

This inventor calculated | required the relationship between the height h right above a nozzle hole, the nozzle hole inlet diameter d, and the spray average particle diameter by experiment. FIG. 4 is a diagram showing experimental results at that time.
From this figure, when (h / d)> 1.5 in the valve open state, the spray average particle size becomes remarkably large, and when (h / d) ≦ 1.5, the spray particle size is stably small. It can be seen that
In this relationship, the frontal collision between the fuel main flow 16a and the U-turn flow 16b is avoided, and the fuel main flow 16a, in which deceleration due to the collision is suppressed, is injected at the inlet 12a of the nozzle hole 12 while maintaining a high flow velocity. It collides with the hole wall 12b and the flow direction changes suddenly.
Therefore, as shown in FIG. 3B, a liquid film 19a is formed by flow separation at the inlet 12a of the injection hole 12, and the fuel is pressed against the injection hole wall 12b, so that the flow in the injection hole 12 causes the curvature of the injection hole 12. The flow 16d along the nozzle 20 is promoted to promote mixing with the air 20 in the nozzle hole 12. And as shown to FIG. 3C, it diffuses as the crescent-like liquid film 19b from the exit of the nozzle hole 12, and atomization of a fuel is accelerated | stimulated.

Further, at the time of injection into the negative pressure atmosphere, after completion of the valve closing, part of the fuel in the cavity 17 surrounded by the valve body 8, the valve seat 10 and the nozzle hole plate 11 is transferred from the nozzle hole 12 into the engine intake pipe by the negative pressure. Sucked out. In this case, in the fuel injection valve described in the specification of Japanese Patent No. 3183556 (Patent Document 4), it passes through the gap between the valve body and the valve seat and directly passes between the main nozzle and the adjacent nozzle holes. A radial U-turn flow that makes a U-turn by an opposing flow at the center of the nozzle hole plate is caused to collide evenly immediately above the nozzle hole to aim for atomization due to turbulence.
For this reason, the flow velocity in the nozzle hole of the cavity fuel sucked out after completion of valve closing under negative pressure is small, and fuel spray with a poor particle size is injected immediately after the valve closing is completed, or fuel cannot be ejected from the nozzle hole. There is a risk of fuel adhering to the end face of the nozzle hole plate around the hole outlet.

Further, in the fuel injection valve described in Patent Document 4, since the U-turn flow in the radial direction is strong, the fuel spray having a poor particle size cannot be injected outside the target injection direction or cannot be separated from the injection hole. In addition, the fuel adhering to the end face of the nozzle hole plate around the nozzle hole outlet is blown off at the time of the next injection, causing a splashing phenomenon in which poor fuel spray is injected outside the target injection direction.
For this reason, fuel adhesion to the wall surface of the intake port increases, and a liquid film flows into the combustion chamber, which may cause deterioration of exhaust gas and controllability of engine output.

On the other hand, in the fuel injection valve of the first embodiment , since the frontal collision between the U-turn flow 16b and the main flow 16a of the fuel is suppressed, turbulence is suppressed in the flow to the nozzle hole 12, The flow velocity of the fuel in the cavity 17 that is sucked out after completion of the valve closing under the negative pressure is large, and the splashing phenomenon is suppressed.

  Further, since the projection 11d is formed on the nozzle hole plate 11 so as to protrude downstream substantially parallel to the ball 13, while avoiding the interference between the valve element 8 and the nozzle hole plate 11, the valve element 8, the valve seat 10 and This is advantageous in reducing the volume of the cavity 17 surrounded by the nozzle hole plate 11. Therefore, the rising speed of the fuel pressure rise in the cavity can be increased immediately after the valve is opened, and good atomization characteristics can be obtained even immediately after the valve is opened.

  Further, the positioning of the nozzle holes 12 during the processing of the nozzle holes 12 is more effective when the nozzle holes 12 are arranged on the outer plane in the radial direction of the projections 11d than when the nozzle holes 12 are arranged in the convex parts 11d of the nozzle hole plate 11. There are also advantages of high accuracy and low flow rate variation and spray variation.

Embodiment 2 FIG .
FIG. 5 is a cross-sectional view showing a main part of the fuel injection valve 1 according to Embodiment 2 of the present invention, and a view when the nozzle hole plate 11 is viewed along the arrow G.
In the fuel injection valve 1 of the second embodiment , the injection holes 12 are arranged on the same circle with the valve seat shaft 10c as the center, and the sprays injected from the plurality of injection holes 12 form one collective spray. Two hole groups 15 are provided, and the two collective sprays are jetted in different directions.
When the distances between the centers of the inlet portions 12a of adjacent nozzle holes 12 in the nozzle hole group 15 are i1 and i2 or the pitch angles are α1 and α2, i1 <i2 or α1 <α2 The hole 12 is arranged.
Other configurations are the same as those of the first embodiment .

In the second embodiment , when the distances between the centers of the inlet portions 12a of the nozzle holes 12 are i1 and i2 or the pitch angles are α1 and α2, the nozzle holes 12 are set so that i1 <i2 or α1 <α2. Are arranged, the strength of the fuel passing between the adjacent nozzle holes 12 is generated, and the U-turn flow 16b mainly flows in the region between the adjacent short nozzle holes 12, and faces the main fuel flow 16a. It is prevented from flowing into the nozzle hole 12.
Accordingly, the deceleration of the main flow 16a of the fuel due to the U-turn flow 16b is suppressed, and further, the relationship of h ≦ 1.5d is established in the valve open state. Therefore, the fuel main flow 16a is maintained at a high flow rate while the inlet portion of the injection hole 12 is maintained. Since the flow direction is suddenly changed at 12a, the fuel flow is separated at the inlet 12a of the nozzle hole 12 and atomization is promoted.
Moreover, in this Embodiment 2 , since the nozzle hole 12 is arrange | positioned so that it may become i1 <i2 or (alpha) 1 <(alpha) 2, the interference of the sprays injected from each nozzle hole 12 is suppressed.
In the second embodiment , the fuel injection valve 1 having two injection hole groups 15 has been described. However, the fuel injection valve has three or more injection groups that are injected in different directions. May be.

Embodiment 3 FIG .
6A is a cross-sectional view showing the main part of the fuel injection valve 1 according to Embodiment 3 of the present invention, and a view when the nozzle hole plate 11 is viewed along the arrow J. FIG. 6B (a) is a cross-sectional view of FIG. 6B (b) is an arrow cross-sectional view along the line LL in FIG. 6A, and FIG. 6B (c) is an arrow cross-sectional view along the line MM in FIG. 6A. FIG.
In the third embodiment , the nozzle holes 112A, 112B, and 112C are arranged on the nozzle hole arrangement surface 11e of the nozzle hole plate 11 at intervals such that α1 <α2 when the pitch angles are α1 and α2. Has been. The injection holes 112A, 112B, and 112C are formed so that the directions in which the fuel is injected are different.
That is, each nozzle hole 112A, 112B, 112C is parallel to the reference line L1 that connects the central axis of each nozzle hole 112A, 112B, 112C and the center of the inlet portion of the valve seat shaft 10c and the reference nozzle hole 112A. When the angle at which the parallel line passing through the center of the inlet portion of the nozzle holes 112B and 112C intersects is viewed along the valve seat shaft 10c, the nozzle hole outward angle (β1, β2) is injected from the nozzle hole 112A. The hole 112B is large, and the nozzle hole 112C is larger than the nozzle hole 112B.
Further, each nozzle hole 112A, 112B, 112C is a vertical line passing through the center of the inlet part of each nozzle hole 112A, 112B, 112C parallel to the central axis of each nozzle hole 112A, 112B, 112C and the valve seat axis 10c. Are formed such that the nozzle hole 112B is larger than the nozzle hole 112C and the nozzle hole 112A is larger than the nozzle hole 112B.
Other configurations are the same as those of the first embodiment .

According to the fuel injection valve 1 of the third embodiment , the injection holes 112A, 112B, 112C have different injection hole outward angles (β1, β2) and injection hole angles (γ0, γ1, γ2). Interference of the spray injected from each nozzle hole 112A, 112B, 112C is suppressed.

Embodiment 4 FIG .
FIG. 7 is a cross-sectional view showing the main part of the fuel injection valve 1 according to Embodiment 4 of the present invention.
In the fuel injection valve 1 of the fourth embodiment, the seat radius at which the ball 13 of the valve body 8 is seated on the valve seat portion 10a of the valve seat 10 when the valve is closed is R, and the inlet portion of the injection hole 12 from the valve seat shaft 10c. When the distance to the center of 12a is r, the relationship between the sheet radius R and the distance r is 0.5 ≦ r / R ≦ 0.8.
Other configurations are the same as those of the first embodiment .

In the fuel injection valve described in Patent Document 4, the injection hole is disposed so as to face the flat portion provided at the tip of the valve body, and has a flow path configuration that is far from the valve seat portion and has a large pressure loss. Therefore, not only does the atomization effect in the stable region in the fully open state not sufficiently obtained, but also the rise speed of the fuel pressure at the inlet of the nozzle hole immediately after the valve opening is slow, and the particle size level immediately after the valve opening is poor. there were.
On the other hand, in the fuel injection valve 1 according to the fourth embodiment, the flow path configuration is almost straight from the clearance between the valve body 8 and the valve seat 10 to the inlet portion 12a of the injection hole 12 and has little pressure loss. Furthermore, h ≦ 1.5d and 0.5 ≦ r / R ≦ 0.8.
Accordingly, since the distance from the valve seat portion 10a to the inlet portion 12a of the nozzle hole 12 is small, the fuel quickly reaches the inlet portion 12a of the nozzle hole 12 at the start of valve opening, and the fuel from the valve seat portion 10a The main flow 16a flows smoothly into the nozzle hole 12.

  FIG. 8 is a diagram when the inventor of the present application obtained a relationship between (r / R) immediately after the valve opening and the spray average particle diameter by experiment. Also from this figure, it can be seen that in the relationship between the seat radius R and the distance r, the spray average particle size is small even immediately after the valve opening in the range of 0.5 ≦ (r / R) ≦ 0.8.

Embodiment 5 FIG .
FIG. 9 is a cross-sectional view of a main part showing a fuel injection valve 1 according to Embodiment 5 of the present invention.
In the fuel injection valve 1 according to Embodiment 5 , the angle between the valve seat portion 10a and the valve seat shaft 10c is α, and the tapered portion 18 between the valve seat portion 10a and the valve seat opening inner wall 10b When the sandwiching angle with the valve seat shaft 10c is β, there is a relationship of 20 ° ≦ (α−β) ≦ 40 °.
Other configurations are the same as those of the first embodiment .

In order to eliminate the uneven spray distribution caused by the positional deviation of the nozzle hole 12 and the horizontal positional deviation between the nozzle hole plate 11 and the valve seat 10, the inlet 12a of the nozzle hole 12 and the valve seat opening inner wall 10b. It is effective to increase the distance.
However, when the diameter of the valve seat opening inner wall 10b is increased, the height of the valve seat opening inner wall 10b inevitably increases in the valve seat portion 10a portion having a constant inclination angle, and fuel flows from the valve seat portion 10a to the valve seat opening portion. When flowing into the nozzle hole 12 along the inner wall 10b, there is a problem in that the flow is separated on the way, fluid energy is lost due to disturbance, and atomization is impaired.
In the fuel injection valve 1 according to the fifth embodiment , the tapered portion 18 is provided between the valve seat portion 10a and the valve seat shaft 10c, so that even if the diameter of the valve seat opening inner wall 10b is increased, the valve seat Since the inner wall height of the opening inner wall 10b can be reduced and the relationship of 20 ° ≦ (α−β) ≦ 40 ° is established, fuel separation at the valve seat portion 10a, the taper portion 18 and the valve seat opening inner wall 10b is minimized. Suppressed to the limit.
Further, the distance between the inlet 12a of the nozzle hole 12 and the valve seat opening inner wall 10b is increased, and the spray is caused by the positional deviation of the nozzle hole 12 and the horizontal positional deviation between the nozzle hole plate 11 and the valve seat 10. It is possible to suppress distribution bias.

  FIG. 10 is a diagram when the inventor of the present application obtains the relationship between (α−β) and the spray average particle size by experiment. From this figure, when 40 ° <(α−β) and 20 °> (α−β), the fuel flow in the valve seat portion 10a, the taper portion 18 and the valve seat opening inner wall 10b is largely separated and disturbed. It can be seen that the fluid energy is lost, the desired spray particle size is not obtained, and the desired spray particle size is obtained in the range of 20 ° <(α−β) <40 °.

Embodiment 6 FIG .
In the fuel injection valve 1 according to Embodiment 6 , the volume of the cavity surrounded by the ball 13, the valve seat 10, and the injection hole plate 11 of the valve body 8 is 0.8 mm ³ or less when the valve is closed.
Other configurations are the same as those of the first embodiment .

In the sixth embodiment , the splashing phenomenon can be suppressed by reducing the suction amount of the cavity fuel after the completion of the valve closing under the negative pressure.
Moreover, the deterioration degree of the spray particle diameter which worsens under negative pressure with respect to atmospheric pressure can be reduced.

FIG. 11 is a diagram when the inventor of the present application obtained a relationship between the cavity volume and the spray average particle diameter under a negative pressure (−500 mmHg) with respect to the atmospheric pressure by an experiment.
From this figure, when the cavity volume exceeds 0.8 mm ³ , the spray average particle diameter becomes remarkably large and deteriorates, and a good spray state cannot be obtained. When the cavity volume is 0.8 mm ³ or less, a stable small spray particle diameter is obtained. It can be seen that the degree of deterioration of the spray particle size is reduced.

The above reference example 1, in the first to sixth embodiments, any but the injection hole plate 11 and the valve seat 10 has been described the fuel injection valve 1 separate injection hole for the first to sixth embodiments The plate and the valve seat may be formed of the same single member.
By using the same member, the coaxiality between the convex portion and the ball of the valve body is improved, the deviation of the fuel flow is reduced, and the variation in the radial direction of the spray can be reduced.

DESCRIPTION OF SYMBOLS 1 Fuel injection valve, 2 solenoid apparatus, 3 housing, 4 core, 4a lower end surface, 5 coil, 6 amateur, 6a upper end surface, 7 valve apparatus, 8 valve body, 9 valve main body, 9a guide part, 10 valve seat, 10a Valve seat part, 10b Valve seat opening inner wall, 10c Valve seat shaft, 10d Seat surface extension, 10e Valve seat sliding part, 11 Injection hole plate, 11a, 11b Welding part, 11c Upper surface, 11d Convex part, 11e Injection hole arrangement Surface, 11f convex outermost diameter portion, 12, 112A, 112B, 112C injection hole, 12a inlet portion, 12b injection hole wall, 13 balls, 13a chamfering portion, 13b guide portion, 14 compression spring, 15 injection hole group, 16a Main flow, 16b U-turn flow, 16d flow, 17 cavity, 18 taper part, 19a, 19b liquid film, 20 air, 50 case, 51 connector 52, fuel passage, h height directly above the injection hole, d injection hole inlet hole.

Claims (8)

It has a valve body for opening and closing the valve seat, and by operating the valve body in response to an operation signal from the control device, fuel is provided on the downstream side of the valve seat through the clearance between the valve body and the valve seat In a fuel injection valve that is injected from a plurality of injection holes provided in the injection hole plate,
The injection hole plate has a protrusion protruding to the downstream side in the valve tip and flat row, and crossing an extension of the valve seat seat of the valve seat radially outside the injection hole plate of the convex portion And the inlet part of the nozzle hole is arranged radially outside the convex part and radially inward from the inner wall of the valve seat opening which is the minimum inner diameter of the valve seat, and the center of the inlet part of the nozzle hole The height h directly above the nozzle hole and the inlet diameter d of the nozzle hole, expressed by a distance in the valve seat axial direction of the valve body tip, have a relationship of h ≦ 1.5d in the valve open state. Fuel injection valve. 2. The fuel injection valve according to claim 1 , wherein the nozzle hole plate and the valve seat are the same integral member. There are one or more nozzle hole groups arranged so that sprays injected from the plurality of nozzle holes form one collective spray, and each nozzle hole of the nozzle hole group is adjacent to the nozzle hole The fuel injection valve according to claim 1 or 2, characterized in that the center-to-center distances of the inlet portions are alternately arranged to be larger and smaller. Among the nozzle hole groups arranged so that the sprays injected from the plurality of nozzle holes form one collective spray, any one of the nozzle holes serves as a reference nozzle hole, and each of the adjacent nozzle holes is a jet nozzle. a central axis of the bore, the angle of the parallel line intersects through the center of the inlet portion of the parallel injection hole with respect to the reference line connecting the center of the inlet portion of the injection hole of the reference and the valve seat axis, wherein the fuel injection valve according to claim 1, characterized in that the angles as viewed along the valve seat axis are different from each other. The adjacent nozzle holes have different nozzle hole angles at which a central axis of the nozzle hole intersects with a vertical line parallel to the valve seat axis and passing through the center of the inlet of the nozzle hole. Item 5. The fuel injection valve according to any one of Items 1 to 4 . The distance r from the valve seat shaft to the center of the inlet portion of the nozzle hole is 0.5 ≦ (r) with respect to the radius R of the valve seat portion where the valve body is seated on the valve seat when the valve is closed. the fuel injection valve according to any one of claim 1 to 5, characterized in that the relationship /R)≦0.8. The fuel injection valve according to any one of claims 1 to 6 , wherein a cavity volume enclosed by the valve body, the valve seat, and the injection hole plate is set to 0.8 mm ³ or less when the valve is closed. . When the valve body is seated on the valve seat when the valve is closed, an angle between the valve seat and the valve seat shaft is α, and the valve seat is formed between the valve seat and the valve seat opening inner wall. when the tapered portion was included angle beta between the valve seat axis is, 20 ° ≦ (α-β ) according to any one of claim 1 to 7, characterized in that a relation of ≦ 40 ° Fuel injection valve.

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