JP2016070070A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a dead volume of a fuel injection valve to be prevented from being increased and a welded diameter of an injection hole plate to be restricted from being expanded and at the same time to enable a sufficient swirl flow for atomization of injected fuel to be generated.SOLUTION: A plurality of fuel chambers 28 each constitutes a slot where a part of a valve seat facing surface 25a of an injection hole plate 25 is recessed, and two of the fuel chambers adjacent to each other are arranged in pairs. A longitudinal axis 29 of a fuel chamber 28 is arranged such that it is rotated about an intersection 30 transverse to a virtual circle 40, along a peripheral direction, so as to get close to the other chamber 28 of the pair. An angle θ formed by radial linear lines connecting each of the intersections 30 of the pair of fuel chambers 28 with a center of a valve seat 23 is set to be larger than an angle α formed by radial linear lines connecting each of the intersections 30 of the fuel chambers 28 that are not in pairs but adjacent to each other with the center of the valve seat 23.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a fuel injection valve used for supplying fuel to an internal combustion engine of an automobile, and more particularly to a fuel injection valve that promotes atomization in spray characteristics.

  In recent years, as exhaust gas regulations for automobile internal combustion engines have been strengthened, atomization of fuel sprays injected from fuel injection valves has been demanded. 2. Description of the Related Art Conventionally, a fuel injection valve that forms a swirl flow until an injected fuel is sprayed from an injection hole provided in an injection hole plate in order to atomize the injection spray is known (for example, Patent Documents). 1 and Patent Document 2).

  The nozzle hole plate disclosed in Patent Document 1 is disposed downstream of the valve seat portion, the diameter of which continuously decreases toward the downstream side where the injected fuel flows, and a central opening through which the injected fuel flows, It has at least two tangential passages extending radially outward from the openings, and a swirl chamber whose downstream end is opened in the tangential direction. Moreover, the nozzle hole is provided in the swirl chamber.

  In addition, the nozzle hole plate disclosed in Patent Document 2 is disposed downstream of the valve seat portion, and a plurality of side holes into which the injected fuel flows, and a tangential passage extending radially outward from each of the side holes. And a swirl chamber whose downstream ends of the tangential passages open in the tangential direction. Moreover, the nozzle hole is provided in the swirl chamber.

  Thus, the injected fuel that has flowed into the central opening or the side hole is rectified and accelerated in the tangential passage, flows into each swirl chamber along the tangential direction, and turns into the swirl chamber. After that, the injected fuel injected while turning in the nozzle hole is assumed to be sprayed to promote atomization.

  However, in the fuel injection valves of Patent Document 1 and Patent Document 2, in order to generate a swirl flow in the swirl chamber, it is necessary to lengthen the tangential passage to some extent and to rectify and accelerate the injected fuel in the passage. As a result, in the fuel injection valves of Patent Document 1 and Patent Document 2, the dead volume increases by the length of the tangential passage.

  On the other hand, in order to suppress an increase in dead volume, it is conceivable to shorten the tangential passage. However, if the tangential passage is shortened, immediately after the start of injection, injected fuel with insufficient rectification and acceleration is injected, and the atomization performance at the initial stage of injection is impaired.

  Also, as a result of lengthening the tangential passage, the weld diameter of the nozzle hole plate is increased. For this reason, the stress which arises in a welding part with a fuel pressure becomes large, and there existed a problem that durability of a nozzle hole plate will fall.

  In order to solve these problems, a part of the upstream nozzle hole plate through which the injected fuel flows is recessed at a plurality of locations along the valve seat opening to form a plurality of elliptical fuel chambers. A fuel injection valve in which one nozzle hole is provided has been proposed (see, for example, Patent Document 3).

  The fuel chamber disclosed in Patent Document 3 includes a portion in which a valve seat portion whose diameter continuously decreases as it goes toward the downstream side where the injected fuel flows, and an upstream plane of the injection hole plate. It is arranged at a position straddling the virtual circle formed by intersecting and the inner diameter of the valve seat opening. The major axis of each fuel chamber is inclined with respect to a line extending in the radial direction from the center of the nozzle hole plate. Further, the nozzle hole is disposed outside the inner diameter of the valve seat opening.

  Thus, the injected fuel that has flowed into the fuel chamber from the valve seat portion collides with the inner wall on the virtual circle side of the fuel chamber, and can thereby generate a swirling flow along the inner wall of the fuel chamber. Therefore, the fuel injection valve according to Patent Document 3 does not require a tangential passage, and can suppress an increase in dead volume and an increase in the weld diameter of the injection hole plate.

JP 1989-271656 A JP 2003-336562 A JP 2010-265865 A

However, the prior art has the following problems.
In each fuel chamber disclosed in Patent Document 3, it is possible to generate a swirling flow with respect to the injected fuel directly flowing into the fuel chamber from the valve seat. However, the injected fuel that does not flow directly into the fuel chamber flows directly toward the nozzle hole without being along the inner wall of the fuel chamber.

  For this reason, the swirl | flow flow along the inner wall of a fuel chamber is not formed, but there exists a problem that atomization performance will be impaired. In order to solve this problem, it is necessary to provide fuel chambers in the circumferential direction without gaps. However, when the number of fuel chambers is increased, the injected fuel flowing into one fuel chamber is reduced due to the injection flow rate, and a sufficient swirl flow may not be obtained. On the other hand, when the number of fuel chambers is reduced, the flow that does not directly flow into the fuel chambers increases, so that atomization significantly deteriorates.

  The present invention has been made to solve the above-described problems, and suppresses an increase in the dead volume of the fuel injection valve and an increase in the weld diameter of the injection hole plate, and is sufficient for atomizing the fuel spray. It aims at obtaining the fuel injection valve which can generate a swirl flow.

  The fuel injection valve according to the present invention has a cylindrical valve seat portion, and the axis of the valve seat portion is such that the inner diameter of the valve seat portion continuously decreases toward the downstream side in the fuel flow direction. A seat having a seat surface inclined to the inner surface of the valve seat portion and a contact portion, and the contact portion is separated from the seat surface so that the fuel is interposed between the seat surface and the contact portion. A valve body that forms a passage and closes the fuel passage by contacting the seat surface with the contact portion, and a valve seat facing surface that faces the valve seat portion on the downstream side of the valve seat in the fuel flow direction are formed. A plurality of indentations are provided as fuel chambers on the valve seat facing surface, and a plurality of injection holes for injecting fuel that has passed through the fuel passage are provided in each of the fuel chambers. The injection hole plate is a virtual extension surface that extends the sheet surface. , Arranged so as to intersect with the valve seat facing surface to form a virtual circle, a part of each fuel chamber exists inside the virtual circle, and each injection hole is formed on the valve seat portion. It exists outside the opening circle of the valve seat when viewing the valve seat along the axis, and the outer shape of each fuel chamber when viewing the nozzle hole plate from the valve seat has a long axis and is long The outer shape includes a curve that swells outward in the direction along the axis, and the valve seat facing surface is provided with a plurality of pairs of fuel chambers with two fuel chambers adjacent to each other in the circumferential direction of the virtual circle, When the nozzle hole plate is viewed from the valve seat, the intersection of each major axis of each fuel chamber and the virtual circle is taken as the reference point of each fuel chamber, and each reference point of each fuel chamber and the axis of the valve seat is When the straight line connecting the two is a radial straight line of each fuel chamber, the long axis of the two fuel chambers that form a pair is The angle θ formed by the radial lines of the two fuel chambers that are inclined with respect to the reference straight line so that the fuel chambers are close to each other outside the imaginary circle is centered on the reference point. It is larger than the angle α formed by the radial straight lines of the two fuel chambers that are not paired.

  According to the present invention, the plurality of fuel chambers provided on the valve seat facing surface with the nozzle hole plate include the virtual extension surface extending the seat surface inclined with respect to the axis of the valve seat portion, and the valve seat facing surface. A plurality of sets of two fuel chambers adjacent to each other in the circumferential direction of a virtual circle formed by intersecting with each other are provided. Moreover, the one end part of each fuel chamber is arrange | positioned in the virtual circle. Further, the long axes of the two fuel chambers that form a pair are inclined with respect to a radial straight line around the reference point so that the fuel chambers come close to each other outside the virtual circle. Thereby, the swirl flow direction of the injected fuel directly flowing into the fuel chamber from the valve seat portion is determined.

  Further, the angle θ formed by the radial straight lines of the two fuel chambers that are paired is larger than the angle α formed by the radial straight lines of the two fuel chambers that are not paired in the adjacent fuel chambers. At this time, due to the inclination of the fuel chamber, the injected fuel flowing from the angle θ side flows into the fuel chamber from the same direction as the swirling flow of the injected fuel flowing directly into the fuel chamber. Therefore, a swirl flow sufficient for atomization of the fuel spray can be generated. Further, since a tangential passage is not required, an increase in the dead volume of the fuel injection valve and an increase in the weld diameter of the injection hole plate can be suppressed.

It is sectional drawing which shows the fuel injection valve in Embodiment 1 of this invention. FIG. 2 is an enlarged view showing the vicinity of a tip portion on the downstream side of the fuel injection valve of FIG. It is an enlarged view which shows the state which looked at the nozzle hole plate along the II-II line of FIG. It is an enlarged view which shows the fuel flow to the fuel chamber of FIG. It is a figure which shows the state by which the injection fuel was injected from the nozzle hole of FIG. It is an enlarged view which shows arrangement | positioning of a nozzle hole when the nozzle hole plate in Embodiment 2 of this invention is seen along the II-II cross section of FIG. It is an enlarged view which shows arrangement | positioning of a nozzle hole when the nozzle hole plate in Embodiment 3 of this invention is seen along the II-II cross section of FIG. It is sectional drawing which shows the state which looked at the fuel chamber in Embodiment 4 of this invention along the IV-IV cross section of FIG. It is a figure which shows the modification of the fuel chamber of FIG. It is a figure which shows the modification of the fuel chamber of FIG.

  Hereinafter, preferred embodiments of the fuel injection valve of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
1 is a cross-sectional view showing a fuel injection valve according to Embodiment 1 of the present invention. In FIG. 1, the fuel injection valve 1 includes a solenoid device 10 and a valve device 20 that operates by driving the solenoid device 10.

  Here, the injected fuel (fuel) is supplied from the supply port 2 above the fuel injection valve 1 and flows in the direction of the central axis inside the fuel injection valve 1 (the direction of arrow A in FIG. 1). That is, the direction of the central axis inside the fuel injection valve 1 is the fuel flow direction. Therefore, hereinafter, the supply port 2 side will be referred to as the upstream side, and the valve device 20 side will be referred to as the downstream side.

  The solenoid device 10 includes a housing 11, a core 12, a coil 13, and an amateur 14. The valve device 20 includes a valve body 21, a valve body 22, and a valve seat 23.

  A rod 15 is fixed inside the core 12, and the load of the compression spring 16 is adjusted by the rod 15. The coil 13 surrounds the lower end (downstream end) of the core 12, and a valve main body 22 constituting a magnetic circuit is provided coaxially with the core 12 at the lower end of the core 12. The valve body 22 is fastened to the core 12 by means such as welding after being press-fitted into the outer portion of the core 12. The fastening portion between the core 12 and the valve body 22 is sealed so that the internal fuel does not leak.

  The housing 11 constituting the magnetic circuit has one end welded to the core 12 and the other end welded to the valve body 22. Therefore, the housing 11 magnetically connects the core 12 and the valve body 22.

  The amateur 14 is provided in the cylindrical valve body 22 so as to be movable in the direction of the central axis of the fuel injection valve 1, and is provided so as to be able to contact and separate from the lower end surface 12 a on the downstream side of the core 12. Yes. In addition, a cylindrical valve body 21 having a ball (contact portion) 24 at one end is press-fitted into the cylindrical armature 14 and then fixed by welding.

  A tubular valve seat 23 having a nozzle hole plate 25 welded to the downstream end is press-fitted into the distal end portion of the downstream side of the valve body 22 and then fixed by welding. First, the nozzle hole plate 25 is fixed to the end of the valve seat 23 on the downstream side of the valve seat 23 with a welded portion 26a. Thereafter, the valve seat 23 integrated with the nozzle hole plate 25 is press-fitted into the valve main body 22 and then fixed to the valve main body 22 by a welded portion 26b.

  At the downstream end in the valve seat 23, there is a cylindrical valve seat portion 23 a with which the ball 24 comes into contact with the urging force of the compression spring 16 adjusted by the rod 15 when the fuel injection valve 1 is not operating. Is formed. The valve seat portion 23a has a continuously decreasing inner diameter in the direction of the central axis inside the fuel injection valve 1 toward the downstream side. Accordingly, the valve seat portion 23a has a seat surface 230a that is inclined so that the distance from the central axis continuously decreases in the direction of the central axis inside the fuel injection valve 1.

  That is, the seat surface 230a is formed on the inner surface of the valve seat portion 23a, and the distance from the axis of the valve seat portion 23a is continuously reduced from the upstream side toward the downstream side. It is inclined with respect to the axis. Thereby, the space surrounded by the seat surface 230a has a truncated cone shape in which the diameter of the circle on the downstream side is smaller than that on the upstream side.

  Further, in the valve seat 23, a cylindrical guide for guiding the ball 24 in the direction of the central axis inside the fuel injection valve 1 from the upstream end portion of the valve seat portion 23 a by the biasing force of the compression spring 16. A surface portion 23b is formed.

  The injection hole plate 25 has a plate shape, and is fixed to the valve seat 23 so that the thickness direction coincides with the central axis direction inside the fuel injection valve 1. That is, the nozzle hole plate 25 closes the opening at the downstream end of the valve seat 23. The nozzle hole plate 25 is provided with a plurality of nozzle holes 27 penetrating in the plate thickness direction.

Next, the operation of the fuel injection valve 1 will be described.
When an operation signal is sent from the engine control device (not shown) to the drive circuit of the fuel injection valve 1, a current is passed through the coil 13 of the fuel injection valve 1, and the housing 11, the core 12, the armature 14, and the valve body Magnetic flux is generated in the magnetic circuit composed of 22.

  As a result, the armature 14 is attracted to the core 12 side (upstream side of the fuel flow) against the urging force of the compression spring 16, and the upper end surface 14 a of the armature 14 contacts the lower end surface 12 a of the core 12. At this time, the ball 24 attached to the distal end portion of the valve body 21 fixed and integrated with the amateur 14 is separated from the seat surface 230a of the valve seat portion 23a while being guided by the guide surface portion 23b, and a gap is formed. The This gap becomes a fuel passage.

  Simultaneously with the formation of this fuel passage, the injected fuel is injected from the injection hole 27 into the engine intake pipe (not shown) through the chamfered portion 24a provided in the ball 24 and the fuel passage.

  On the other hand, when an operation stop signal is sent from the engine control device to the drive circuit of the fuel injection valve 1, the current supply to the coil 13 of the fuel injection valve 1 is stopped, and the magnetic flux in the magnetic circuit decreases. As a result, the upper end surface 14 a of the armature 14 is separated from the lower end surface 12 a of the core 12 by the urging force of the compression spring 16. Accordingly, the ball 24 comes into contact with the seat surface 230a of the valve seat portion 23a while being guided by the guide surface portion 23b, and the fuel passage is closed. Thereby, the fuel injection from the nozzle hole 27 is completed.

  In recent years, since exhaust gas regulations have been strengthened, atomization of fuel spray injected from the nozzle holes 27 in fuel injection is required. The present invention is characterized by the nozzle hole plate 25 used for realizing atomization of fuel spray.

  FIG. 2 is an enlarged view showing the vicinity of the tip portion on the downstream side of the fuel injection valve 1 of FIG. 1 and a cross-sectional view showing a state where the nozzle hole plate 25 is seen along the line II-II. FIG. 3 is an enlarged view showing a state in which the nozzle hole plate 25 is viewed along the line II-II in FIG. As shown in FIG. 2, the virtual extension surface 23c (thin line in FIG. 2) of the seat surface 230a that is inclined so that the distance from the axis of the valve seat portion 23a becomes smaller toward the downstream side, The nozzle hole plate 25 is arranged so as to form a virtual circle 40 intersecting with the upstream surface (valve seat facing surface) 25a of the hole plate 25.

  A plurality of recesses along the central axis direction inside the fuel injection valve 1 are formed as fuel chambers 28 on the valve seat facing surface 25a of the injection hole plate 25 arranged in this way. The fuel chambers 28 are arranged at a distance from each other along the circumferential direction of the virtual circle 40.

  The outer shape of the fuel chamber 28 includes a long axis 29 when viewed along the central axis direction inside the fuel injection valve 1 and includes a curve that rises outward in the direction along the long axis 29. In this example, the outer shape of the fuel chamber 28 is elliptical when viewed along the direction of the central axis inside the fuel injection valve 1.

  As shown in FIGS. 2 and 3, the fuel chamber 28 is located on the downstream side of the valve seat 23 in the radial direction of the virtual circle 40 from the inside of the virtual circle 40 along the central axis direction inside the fuel injection valve 1. It is arranged at a position straddling the virtual circle 40 and the opening circle 41 to the outside of the opening circle 41 when viewing the opening. That is, one end of each fuel chamber 28 is disposed within the virtual circle 40.

  Each fuel chamber 28 is provided with one nozzle hole 27. Each injection hole 27 is disposed at a position radially outside the fuel injection valve 1 with respect to the opening circle 41.

  Further, the fuel chamber 28 is configured as a pair of two adjacent to each other in the circumferential direction of the virtual circle 40, and at least two pairs (a plurality of sets) of fuel chambers 28 are provided. In this example, there are two pairs of fuel chambers 28, that is, four fuel chambers, which are referred to as fuel chambers 28a, 28b, 28c, and 28d, respectively, clockwise from the upper right in FIG. The chamber 28a and the fuel chamber 28b, and the fuel chamber 28c and the fuel chamber 28d are paired. Each fuel chamber 28 is molded by half punching.

  The long axis 29a of the fuel chamber 28a is a radial straight line L that connects the intersection (reference point) 30a that intersects the virtual circle 40 and the center of the valve seat 23 (that is, the central axis inside the fuel injection valve 1). Rather, it is provided at a position rotated around the intersection 30a toward the paired fuel chamber 28b by a desired angle (arrow B in FIG. 3) set at the time of design. That is, with respect to the radial direction of the virtual circle 40, the end portion outside the virtual circle 40 of the long axis 29 a of the fuel chamber 28 a is paired along the circumferential direction of the fuel injection valve 1 around the intersection 30 a. It inclines with respect to the radial straight line L so that the chamber 28b side may be approached.

  Similarly, the ends of the long axes 29b, 29c, 29d of the fuel chambers 28b, 28c, 28d outside the virtual circle 40 are similarly centered on the intersections 30b, 30c, 30d intersecting the virtual circle 40. It is provided in the position rotated so that it may approach the paired fuel chamber 28 side along the circumferential direction, respectively. Therefore, the two long axes 29 to be paired are inclined with respect to the radial straight line around the intersection 30 so that the fuel chambers 28 come close to each other outside the virtual circle 40.

  FIG. 4 is an enlarged view showing a fuel flow to the fuel chamber 28a of FIG. FIG. 5 is a view showing a state in which the injected fuel is injected from the injection hole 27 of FIG.

  As shown in FIG. 4, the fuel flow flowing into the fuel chamber 28a along the seat surface 230a of the valve seat portion 23a is pressed against the wall surface 280a located inside the virtual circle 40, and then the wall surface 280a and It flows in the direction of arrow C along the inner wall 280b of the fuel chamber 28a located outside the virtual circle 40. Thereafter, the structure flows into the inlet (upstream side of the nozzle hole 27) of the nozzle hole 27 while turning around the nozzle hole 27. As a result, the injected fuel is pressed against the inner wall of the nozzle hole 27 while swirling in the nozzle hole 27, so that the injection fuel does not fill the nozzle hole 27, and the thin crescent-shaped liquid film 50 as shown in FIG. It is injected from the outlet of the nozzle hole 27 (downstream side of the nozzle hole 27).

  Here, as shown in FIG. 3, the angle formed by the radial straight line M connecting the intersection 30b of the fuel chamber 28b and the center of the valve seat 23, which is paired with the fuel chamber 28a, and the radial straight line L is θ (°). And Further, although not paired with the fuel chamber 28a, the angle formed by the radial straight line L connecting the intersection 30d of the fuel chamber 28d adjacent to each other and the center of the valve seat 23 and the radial straight line L is α (°). And

  At this time, the relationship between the angle θ and the angle α is such that the angle θ is larger than the angle α (that is, the angle α <angle θ). This is because the swirl direction created by the injected fuel flowing into the fuel chamber 28a from the range of the angle θ (arrow D in FIG. 4) and the swirl direction created by the injected fuel flowing into the fuel chamber 28a from the range of the angle α (shown in FIG. 4). This is because the reverse of the broken line arrow E), and if the injected fuel flows equally into the fuel chamber 28a from both, the swirl flows are disturbed.

  Thus, by narrowing the angle α to be smaller than the angle θ, most of the fuel flow that does not directly flow into the fuel chamber 28a from the valve seat portion 23a is bypassed as indicated by the arrow D in FIG. Into the fuel chamber 28a. As a result, the injected fuel that does not directly flow into the fuel chamber 28a can also form a swirling flow within the fuel chamber 28a.

  The injected fuel flowing into the fuel chamber 28a from the range of the angle α becomes a swirling flow in the direction opposite to the arrows C and D as shown by the arrow E in FIG. Since the influence of the injected fuel flowing into 28a is strong, the fuel flows along arrows C and D.

  In the first embodiment, the number of the fuel chambers 28 is four, so that the number of nozzle holes 27 is four. This aims at suppressing spray adhesion to the intake port. By providing the long axis 29 of each fuel chamber 28 at a position rotated by a desired angle toward the paired fuel chamber 28 around the intersection 30 intersecting with the virtual circle 40, the injected fuel can be paired. The liquid film 50 formed along the inner wall of the nozzle hole 27 moves toward the outlet of the nozzle hole 27 while turning. Therefore, the crescent-like liquid film 50 injected from each injection hole 27 is injected in a direction approaching the pair of fuel chambers 28 as shown in FIG.

  As a result, the collective spray 51 sprayed from the two pairs of nozzle holes 27 has a flat shape (that is, a shape in which a circle is horizontally long) as shown in FIG. In a typical engine, the axis of the injector and the axis of the intake valve are not parallel. The intake passage is curved near the intake valve umbrella. For this reason, when the intake passage outlet is viewed from the injector side, it has a flat shape. As a result, the spray cross-section is not a circle but a flat collective spray 51 as shown in FIG. 5 is injected, so that the spray adhering to the intake passage can be suppressed while injecting the intake valve. Controllability is improved.

  In the fuel injection valve according to the first embodiment, at least two pairs of fuel chambers provided in the nozzle hole plate are configured as a pair of two fuel chambers adjacent to each other in the circumferential direction. In addition, one end of the fuel chamber is arranged in a virtual circle, and the long axes of the two fuel chambers that form a pair are relative to a radial line centering on the intersection so that the fuel chambers are close to each other outside the virtual circle. Is inclined. Furthermore, the angle θ formed by the radial straight line connecting each intersection of the fuel chambers and the center of the valve seat is a radial connecting each intersection of fuel chambers that are not paired but adjacent to each other and the center of the valve seat. It is set to be larger than the angle α formed by the straight line.

  By having such a configuration, both the injected fuel that flows directly into the fuel chamber from the valve seat and the injected fuel that does not flow directly into the fuel chamber from the valve seat form a swirl flow along the wall surface of the fuel chamber. can do. Thereby, a swirl flow sufficient for atomization of fuel spray can be generated.

  Further, it is possible to eliminate the necessity of providing a tangential passage for rectifying and accelerating the injected fuel, as in Patent Documents 1 and 2 which are conventional techniques. As a result, since the nozzle hole plate does not increase in the radial direction, it is possible to suppress an increase in the welding diameter. Along with this, an increase in the dead volume of the fuel injection valve can be suppressed.

  Moreover, since the expansion of the weld diameter of the nozzle hole plate can be suppressed, the pressure resistance of the welded portion can be improved. Furthermore, since the fuel chamber is formed by half-cutting, the fuel chamber can be easily formed as compared with other processing methods.

Embodiment 2. FIG.
FIG. 6 is an enlarged view showing the arrangement of the nozzle holes 27 when the nozzle hole plate 25 in the second embodiment of the present invention is viewed along the II-II cross section of FIG. As shown in FIG. 6, the centers of the nozzle holes 27 adjacent to each other are arranged at the same angle around the center of the valve seat 23. That is, in this example, in the straight line connecting the center of the valve seat 23 and the center of each of the four nozzle holes 27, the angle formed by the adjacent straight lines is 90 degrees. Other configurations are the same as those of the first embodiment.

  In the fuel injection valve according to the second embodiment, the centers of the nozzle holes adjacent to each other are arranged at the same angle with the center of the valve seat as the center. Thus, by providing the configuration in which the nozzle holes are arranged at equal intervals on the circumference, it is possible to avoid interference between the liquid films immediately after being injected from each nozzle hole. As a result, atomization of the fuel spray injected from the nozzle hole can be improved.

Embodiment 3 FIG.
FIG. 7 is an enlarged view showing the arrangement of the nozzle holes 27 when the nozzle hole plate 25 in the third embodiment of the present invention is viewed along the II-II cross section of FIG. As shown in FIG. 7, a swirl chamber 281 that extends the fuel chamber 28 is provided at the radially outer end of the fuel chamber 28.

  The swirl chamber 281 is provided at the end of the fuel chamber 28 in the radial direction of the fuel injection valve 1. The swirl chamber 281 is provided on the radially outer side of the fuel injection valve 1 with respect to the opening circle 41. In this example, the swirl chamber 281 is a portion in which the end portion in the radial direction of the fuel chamber 28 of the first embodiment shown by the broken line in FIG. 7 bulges toward the paired fuel chamber 28. .

  At this time, the swirl chamber 281 bulges toward the paired fuel chamber 28 along the tangential direction of the swirling flow generated in the fuel chamber 28. As a result, the radially inner wall 280 b of the fuel chamber 28 has a shape close to an arc shape by the swirl chamber 281. Here, the curve that swells outward in the direction along the major axis 29 of the outer shape of the fuel chamber 28 includes the curve of the swirl chamber 281 in addition to the elliptical portion of the first embodiment.

  The nozzle hole 27 is provided at a position that is offset toward the fuel chamber 28 that forms a pair with respect to the long axis 29 of the fuel chamber 28, that is, a position that is shifted toward the swirl chamber 281. Therefore, at least a part of the nozzle hole 27 enters the swirl chamber 281. Other configurations are the same as those of the first embodiment.

  In such a fuel injection valve according to the third embodiment, the fuel chamber is expanded along the tangential direction of the swirl flow at the radially outer end of the fuel chamber at a position closer to the paired fuel chamber side than the long axis. A swirl chamber is provided. Further, at least a part of the nozzle hole is provided so as to enter the swirl chamber.

  By providing such a configuration, the inner wall of the fuel chamber in which the swirl chamber is provided is close to an arc shape, so that the centrifugal force of the swirling flow increases and the swirling flow can be further strengthened. As a result, atomization of the fuel spray injected from the nozzle hole can be improved.

  In the first to third embodiments, the ratio between the size of the diameter of the injection hole 27 provided in each fuel chamber 28 and the length of the injection hole 27 in the central axis direction inside the fuel injection valve 1 is as follows. There is no particular limitation. Here, the ratio between the diameter and the length of each nozzle hole 27 may be the same, but, for example, the ratio between the diameter and the length of the nozzle hole 27 of the paired nozzle hole 27 may be different. By adjusting the ratio between the diameter and the length of the nozzle hole 27, the spray direction and the spread angle of the liquid film 50 can be adjusted. Thereby, interference between the liquid films 50 ejected from the paired nozzle holes 27 can be avoided. Therefore, atomization of the fuel spray injected from the nozzle hole can be improved.

Embodiment 4 FIG.
FIG. 8 is a cross-sectional view showing a state in which fuel chamber 28 according to Embodiment 4 of the present invention is viewed along the IV-IV cross section of FIG. 4. As shown in FIG. 8, the injection hole 27 in the fourth embodiment is molded by being punched from the upstream side of the injection hole plate 25 by press working. For this reason, roundness R will be given to the edge part of the inlet_port | entrance (upstream side of the nozzle hole 27) of the nozzle hole 27 along the circumferential direction of the nozzle hole 27. FIG. Other configurations are the same as those of the first embodiment.

  In such a fuel injection valve according to Embodiment 4, the edge portion of the inlet of the injection hole is rounded along the circumferential direction of the injection hole. By providing such a configuration, fuel separation at the inlet portion of the nozzle hole can be suppressed. Therefore, the swirl flow inside the nozzle hole can be enhanced. As a result, the spread of the liquid film after the injection can be increased, and the atomization of the fuel spray injected from the injection hole can be improved.

  In the first to fourth embodiments described above, the example in which the fuel chamber 28 is elliptical (or an example in which the swirl chamber 281 is further provided for the elliptical shape) has been described. However, the present invention is not limited to this. FIG. 9 is a view showing a modification of the fuel chamber 28 of FIG. FIG. 10 is a view showing a modification of the fuel chamber 28 of FIG.

  As shown in FIG. 9, the fuel chamber 28 is composed of a semicircular semicircular part (arc shape) that is spaced from each other in the radial direction, and a linear part that connects the semicircular part with a straight line. It may be an elongated slot shape. Here, the curve rising outward in the direction along the major axis 29 of the outer shape of the fuel chamber 28 is a semicircular portion. Further, as shown in FIG. 10, a swirl chamber 281 may be provided at the radially outer end of the long hole-shaped fuel chamber 28. Here, the curve rising outward in the direction along the major axis 29 of the outer shape of the fuel chamber 28 includes the curve of the swirl chamber 281 in addition to the semicircular portion. Even if it is such a structure, the effect similar to previous Embodiment 1-4 can be acquired.

  DESCRIPTION OF SYMBOLS 1 Fuel injection valve, 22 Valve main body, 23 Valve seat, 23a Valve seat sheet | seat part, 23c Extended surface, 24 Ball (contact part), 25 Injection hole plate, 25a Valve seat opposing surface, 27 Injection hole, 28 Fuel chamber, 29 Long axis of fuel chamber, 30 intersections, 40 virtual circles, 281 swirl chamber.

Claims (7)

A seat having a cylindrical valve seat portion that is inclined with respect to the axis of the valve seat portion so that the inner diameter of the valve seat portion continuously decreases toward the downstream side in the fuel flow direction. A valve seat whose surface is formed on the inner surface of the valve seat portion;
A fuel passage is formed between the seat surface and the contact portion by separating the contact portion from the seat surface, and the contact portion contacts the seat surface; A valve body that closes the fuel passage, and a valve seat facing surface that faces the valve seat portion on the downstream side of the valve seat in the fuel flow direction are formed, and a plurality of recesses are formed on the valve seat facing surface. A plurality of nozzle holes provided as fuel chambers, each of which has a plurality of nozzle holes for injecting fuel that has passed through the fuel passage, are provided in each of the fuel chambers;
The nozzle hole plate is arranged such that a virtual extension surface obtained by extending the seat surface intersects with the valve seat facing surface to form a virtual circle,
A part of each of the fuel chambers exists inside the virtual circle,
Each nozzle hole is present outside the opening of the valve seat when viewing the valve seat along the axis of the valve seat,
The outer shape of each fuel chamber when the nozzle hole plate is viewed from the valve seat is an outer shape having a long axis and including a curve that bulges outward in the direction along the long axis.
The valve seat facing surface is provided with a plurality of pairs of the fuel chambers with a pair of two fuel chambers adjacent to each other in the circumferential direction of the virtual circle,
When the nozzle hole plate is viewed from the valve seat, the intersection of each of the major axis of each of the fuel chambers and the virtual circle is defined as a reference point of each of the fuel chambers, and each of the reference points of each of the fuel chambers And a straight line connecting the axis of the valve seat portion with the radial straight line of each fuel chamber,
The long axes of the two fuel chambers that form a pair are inclined with respect to the radial line around the reference point so that the fuel chambers come closer to each other outside the virtual circle,
The angle θ formed by the radial lines of the two fuel chambers that form a pair is larger than the angle α formed by the radial lines of the two fuel chambers that are not paired in the adjacent fuel chambers. Injection valve. The fuel injection valve according to claim 1, wherein the centers of the nozzle holes adjacent to each other in the circumferential direction of the virtual circle are arranged at the same angle with the center of the valve seat as a center. A swirl chamber that extends the fuel chamber toward the paired fuel chamber is provided at a radially outer end of the valve seat of the plurality of fuel chambers,
The fuel injection valve according to claim 1, wherein at least a part of the injection hole is formed in the swirl chamber. The length of the fuel flow direction of the nozzle hole and the ratio of the diameter of the nozzle hole are different between the paired nozzle holes. Fuel injection valve. The fuel injection valve according to any one of claims 1 to 4, wherein the plurality of fuel chambers are formed by half-blanking. The nozzle hole is molded by pressing from the valve seat facing surface side by pressing,
The fuel injection valve according to any one of claims 1 to 5, wherein an edge of the inlet of the injection hole on the side facing the injection valve seat is rounded along a circumferential direction. The fuel injection valve according to any one of claims 1 to 6, wherein two pairs of the fuel chambers, each having two fuel chambers adjacent to each other, are provided.

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