JP6448814B2 - Fuel injection valve - Google Patents

Description

  The present invention relates to a fuel injection valve, and more particularly to a fuel injection valve used for supplying fuel to an internal combustion engine.

  In an internal combustion engine such as an automobile, the amount of fuel supplied is controlled using a fuel injection valve. In recent years, exhaust gas regulations for internal combustion engines have been strengthened, and atomization of fuel sprays injected from fuel injection valves has been required. In the prior arts disclosed in Patent Documents 1 and 2, it is considered to form a swirl flow in the fuel injection valve in order to atomize the fuel.

  The fuel injection valve according to Patent Document 1 includes a valve casing formed symmetrically with respect to the longitudinal axis. A valve closing member that cooperates with the valve seat surface is arranged inside the valve casing. A central opening is provided downstream of the valve seat surface, and at least two tangential passages extend radially from the central opening. Each tangential passage opens tangentially to each swirl chamber. Each metering opening for fuel leads from the center of the swirl chamber to the outside.

  The fuel rectified and accelerated by the guide passage flows into the swirl chamber. The fuel is swirled in the swirl chamber and then injected from the nozzle hole plate outlet while swirling in the nozzle hole. The ejected matter is a hollow conical spray, which is supposed to promote atomization. In such a configuration, since the fuel flows into the swirl chamber from only one direction, the swirl flow becomes non-homogeneous. Since the fuel liquid film formed on the inner wall of the nozzle hole is uneven in thickness, it cannot be said that the degree of atomization after injection is sufficient.

  The fuel injection valve according to Patent Document 2 has a single injection hole arranged at a radial interval with respect to the valve opening. Two arc-shaped vortex forming passages arranged in a mirror image symmetry with each other are guided in the vortex forming chamber of the single injection hole. In such a configuration, since there are two passages guided to the swirl chamber, the swirl flow is uniform and the atomization is improved. In order to achieve further atomization, it is desirable to make multiple injection holes, but the two passages make the layout low and make it difficult to make multiple injection holes.

JP 1989-271656 A International Publication No. 2013/023838

  The method in which two opposing flow paths are provided for the swirl chamber has good homogeneity of the swirl flow, but because there are two passages, the layout is low, and atomization by multi-hole injection can be achieved. It was difficult. Therefore, a structure that produces a uniform swirl flow while having good layout properties is desired.

  The present invention has been made in order to solve the above-described problems. In a fuel injection valve including a valve driven by a solenoid device and a valve seat disposed downstream of the plunger, The objective is to further atomize the fuel while maintaining the homogeneity of the flow.

  A fuel injection valve according to the present invention includes a plunger driven by a solenoid device, a valve seat disposed on the downstream side of the plunger and having an opening, a radial portion having a branching portion, an introducing portion, a cylindrical portion, and a turning portion. An injection hole plate in which an injection hole is opened on the downstream side of the cylindrical portion, the introduction portion is connected to the branch portion at one end, and the cylindrical portion and the swivel at the other end The swivel part is surrounded by a terminal surface that encircles the cylindrical part and then circumscribes the cylindrical part. The terminal surface of the swivel part is only angle θ with respect to the central axis of the introduction part. The angle θ is in the range of 0 ° or more and 45 ° or less, and the ratio W2 / W1 of the width W2 of the turning portion to the width W1 of the introduction portion is 0.3 or more and 0.7 It is characterized by being in the following range.

  The fuel injection valve according to the present invention has a cylindrical cylindrical portion and a swivel portion on the outer peripheral side thereof, the injection hole is opened at the center of the cylindrical portion, and the end portion of the swivel portion is connected to the outer peripheral portion of the cylindrical portion. By setting the end surface L and the angle θ formed by the end surface L and the central axis of the introduction portion to be 0 ° ≦ θ ≦ 45 °, the flow A directly flows from the introduction portion in the cylindrical portion and the swivel portion The flow B flowing into the cylindrical portion is opposed. Further, when the width of the introduction part is W1 and the width of the swivel part is W2, by setting 0.3 ≦ W2 / W1 ≦ 0.7, the strengths of both flows become substantially equal.

  By the above, compared with the case where a swirl flow is formed by the flow from only one direction, the swirl flow becomes homogeneous. As a result, the film thickness of the fuel liquid formed on the inner wall of the nozzle hole becomes uniform, so that the degree of atomization becomes good. Furthermore, compared with a method in which two independent opposing flow paths are provided for the swirl chamber, the same atomization effect can be obtained, but the shape is compact. This facilitates the formation of multiple injection holes, and the injection flow rate per injection hole is reduced. Further atomization can be achieved by thinning the fuel liquid film formed after injection.

It is sectional drawing which shows the whole structure of the fuel injection valve by embodiment. It is sectional drawing (FIG. 2A) showing the front-end | tip part of a fuel injection valve, and top view (FIG. 2B) showing the nozzle hole plate of a fuel injection valve. It is a top view showing the hollow formed in the nozzle hole plate. It is an enlarged view showing the introduction part, cylindrical part, and turning part which were formed in the nozzle hole plate. It is a figure showing the relationship of angle (theta), the width W1 of an introducing | transducing part, and the width W2 of a turning part. It is a figure which shows two fuel flows which generate | occur | produce in a cylindrical part and a turning part. It is the figure which showed the correlation of angle (theta) which the end surface L and the central axis of an introducing | transducing part comprise, and atomization. It is the figure which showed the correlation of the ratio of the width W1 of an introducing | transducing part and the width W2 of a turning part, and atomization. It is a figure explaining the relationship between the width W1 of an introduction part, and the diameter D1 of a cylindrical part. FIG. 5 is a diagram showing two fuel flows in the fuel injection valve of the second embodiment. It is a top view (Drawing 11A) and a sectional view (Drawing 11B) of a hollow by a 3rd embodiment. FIG. 10 is a diagram showing two fuel flows in the fuel injection valve of the third embodiment. FIG. 10 is a plan view illustrating a recess formed in a nozzle hole plate according to a fourth embodiment.

  A fuel injection valve according to an embodiment of the present invention will be described below with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals, and the sizes and scales of the corresponding components are independent. For example, when the same components that are not changed are illustrated in cross-sectional views in which a part of the configuration is changed, the sizes and scales of the same components may be different. In addition, the configuration of the fuel injection valve actually includes a plurality of members, but for the sake of simplicity, only the portions necessary for the description are shown, and the other portions are omitted.

Embodiment 1 FIG.
FIG. 1 shows a cross section of a fuel injection valve according to an embodiment of the present invention. In the fuel injection valve 100, the fuel introduced from the fuel supply port is atomized and discharged from the fuel injection port. The fuel injection valve 100 includes a drive circuit 1, a solenoid device 4, a housing 5, a core 6, an armature 8, a plunger 9, a valve body 11, a valve seat 12, an injection hole plate 13, and the like. An operation signal and a stop signal are sent to the drive circuit 1 of the fuel injection valve 100 from an engine control device. In accordance with these signals, the drive circuit 1 supplies a drive current to the solenoid device 4 to drive the plunger 9. The drive current generates a magnetic flux in a magnetic circuit composed of the armature 8, the core 6, the housing 5, and the valve body 11. The valve seat 12 is disposed on the downstream side of the plunger 9.

  The housing 5 corresponds to a yoke portion of the magnetic circuit. The core 6 corresponds to a fixed core portion of the magnetic circuit. The armature 8 corresponds to the movable iron core portion of the magnetic circuit. The solenoid device 4 includes a coil 7 and a compression spring 16. The plunger 9 is composed of a valve body 10 and a ball 15. The valve body 11 is welded after being press-fitted into the outer diameter portion of the core 6. The armature 8 is welded after being press-fitted into the valve body 10. A nozzle hole plate 13 is coupled to the valve seat 12. The nozzle hole plate 13 is provided with a plurality of nozzle holes 14 penetrating in the plate thickness direction. A plurality of chamfered portions are formed on the ball 15 of the plunger 9.

  FIG. 2A is an enlarged view of the fuel outlet (valve body tip) of the fuel injection valve 100. In the figure, a ball 15, a valve seat 12, and a nozzle hole plate 13 are displayed. The valve seat 12 and the injection hole plate 13 are connected by a weld bead 13b. The valve seat 12 is provided with a valve seat opening 12b at the center. When the fuel injection valve 100 is closed, the ball 15 of the plunger 9 presses the valve seat portion 12a. The nozzle hole plate 13 is provided with a plurality of nozzle holes 14 penetrating in the plate thickness direction. The recess 13 a is formed by recessing a part of the upstream side of the nozzle hole plate 13. FIG. 2B is a plan view showing the shape of the recess 13 a formed in the nozzle hole plate 13. As for the nozzle hole plate 13, the radial hollow 13a is processed in the upstream. The plurality of nozzle holes 14 are connected to the recess 13a. When the fuel passes through the valve seat opening 12 b, the fuel is introduced into the recess 13 a and is sprayed from the plurality of injection holes 14.

  Next, the operation of the fuel injection valve 100 will be described. When an operation signal is sent from the engine control device to the drive circuit 1 of the fuel injection valve 100, a current is passed through the coil 7 of the solenoid device 4, and the armature 8, the core 6, the housing 5, and the valve body 11 are configured. Magnetic flux is generated in the magnetic circuit. The armature 8 is sucked toward the core side, and the valve body 10 that is integral with the armature 8 is separated from the valve seat portion 12a to form a gap. The fuel is injected from the chamfered portion 15a of the ball 15 welded to the tip of the valve body 10 through the gap between the valve seat portion 12a and the valve body 10 through the plurality of nozzle holes 14 into the engine intake passage.

  Next, when an operation stop signal is sent from the engine control device to the drive circuit 1 of the fuel injection valve 100, energization of the drive current to the coil 7 of the solenoid device 4 is stopped. Due to the reduction of the coil current, the magnetic flux in the magnetic circuit is reduced. The compression spring 16 pushing the valve body 10 in the valve closing direction closes the ball 15 and the gap between the valve body 10 and the valve seat portion 12a, and the fuel injection ends. The armature 8 and the valve body 10 slide on the guide portion 11 a of the valve body 11, and the upper surface 8 a of the armature 8 contacts the lower surface of the core 6 in the valve open state.

  The detailed shape of the recess 13a formed on the upstream side of the nozzle hole plate 13 will be described with reference to FIG. The recess 13 a includes the branch portion 2, the introduction portion 18, and the fuel chamber 17. The fuel chamber 17 surrounds the nozzle hole 14. The introduction part 18 introduces fuel into the fuel chamber 17 from the valve seat opening 12b. A plurality of introduction portions 18 are branched from the branch portion 2. The nozzle hole 14 is formed in the fuel chamber 17. The fuel enters the introduction part 18 via the branch part 2 from the valve seat opening part 12b formed in the valve seat part 12a. The central axis of the introduction portion 18 extends radially from the valve seat center. The branch portion 2 is housed in the valve seat opening 12b.

FIG. 4 shows the configuration of the fuel chamber 17 in detail. The fuel chamber 17 includes a cylindrical portion 19 having a cylindrical shape and a swiveling portion 20 that surrounds a substantially half circumference of the outer periphery of the cylindrical portion 19. The nozzle hole 14 is opened at the center of the cylindrical portion 19. The introduction part 18 communicates with both the cylindrical part 19 and the turning part 20. The end surface L of the swivel unit 20 circumscribes the outer periphery of the cylindrical portion 19 and serves as the end portion of the swivel unit 20. The introduction part 18 has a central axis 3. The introduction part 18 has one end connected to the branch part 2 and the other end connected to the cylindrical part 19 and the turning part 20. Accordingly, in the nozzle hole plate 13, a radial recess 13 a having the branch part 2, the introduction part 18, the cylindrical part 19, and the swivel part 20 is processed on the upstream side, and the injection hole 14 is opened on the downstream side of the cylindrical part 19. ing. The swivel unit 20 is closed at the end surface circumscribing the cylindrical part 19 after partially surrounding the cylindrical part 19.

  Next, the size of the fuel chamber 17 and the introduction portion 18 will be described with reference to FIG. The introduction part 18 has a width W1. The turning unit 20 has a width W2. The angle θ represents an angle formed between the end surface L of the turning unit 20 and the central axis 3 of the introduction unit 18. The swivel unit 20 is continuous with the introduction unit 18 because the outer peripheral portion is in contact with the inner wall of the introduction unit 18. The terminal part of the turning part 20 is the terminal surface L of the outer peripheral part of the cylindrical part 19. In the fuel injection valve 100 according to the present embodiment, there is a relationship of 0.3 ≦ W2 / W1 ≦ 0.7. The angle θ satisfies the relationship of 0 ° ≦ θ ≦ 45 °.

  FIG. 6 shows the direction of the fuel flow generated in the recess 13 a processed in the nozzle hole plate 13. In the figure, two typical fuel routes flowing from the introduction part 18 into the cylindrical part 19 and the swivel part 20 are displayed. A flow 21 represents a flow that directly enters the cylindrical portion 19 from the introduction portion 18. On the other hand, the flow 22 represents the flow from the introduction unit 18 through the turning unit 20.

  In the fuel injection valve 100 according to the present embodiment, the flow 21 that directly enters the cylindrical portion 19 from the introducing portion 18 and the flow 22 that passes through the swiveling portion 20 from the introducing portion 18 face each other and flow into the cylindrical portion 19. The flow 21 that directly enters the cylindrical portion 19 from the introduction portion 18 flows into the cylindrical portion 19 while being drawn toward the injection hole. Here, in order to create a homogeneous swirl flow, it is important that the two flows are completely opposed.

  FIG. 7 is a diagram showing the correlation between the angle θ formed by the end surface L and the central axis 3 of the introducing portion 18 and the atomization. The result of having measured the fuel particle size after the injection with respect to the specification A and the specification B is shown. By adjusting the angle θ between the end surface L and the central axis of the introduction portion 18 and changing the angle at which the flow 22 passing through the swivel portion 20 flows into the cylindrical portion 19, the two flows can be completely opposed to each other. I can do it. The optimum value of the angle θ formed by the end surface L and the central axis of the introduction portion 18 varies depending on the diameter of the cylindrical portion 19, the width W2 of the turning portion 20, the width W1 of the introduction portion 18, and the like, as shown in FIG. In both specifications, atomization of the fuel spray was good in the range of 0 ° ≦ θ ≦ 45 °.

  FIG. 8 is a diagram showing the correlation between the ratio W2 / W1 between the width W1 of the introduction part 18 and the width W2 of the turning part 20 and the atomization. It is desirable that the strengths of the two opposing flows be uniform to some extent. The strength of the flow passing through the swivel unit 20 varies depending on the ratio W2 / W1 of the width W2 of the swivel unit 20 to the width W1 of the introduction unit 18. As shown in the figure, by setting in the range of 0.3 ≦ W2 / W1 ≦ 0.7, the balance between the strengths of the two flows was good and the atomization of the fuel spray was good.

  Two opposing fuel flows that have flowed into the cylindrical portion 19 are directed toward the injection hole 14. The fuel injection valve 100 injects fuel particles with a good degree of atomization and a small variation in the degree of atomization by creating a thin liquid film having a uniform thickness along the inner wall of the injection hole. As described above, a swirl flow having high homogeneity is generated by creating a swirl flow by the flow from two opposite directions, so that the liquid film thickness along the inner wall of the nozzle hole is also uniform. Therefore, as compared with a method in which a swirl flow is generated by a flow from one direction, a decrease in atomization due to a deviation in the thickness of the fuel liquid film can be eliminated, so the degree of atomization is improved.

  In addition, for the method of providing two opposing flow paths independent of the swirl chamber, the fuel chamber has a simple configuration and the layout is improved while obtaining the same atomization effect. . This facilitates the formation of multiple injection holes, so that the injection amount allocated per injection hole can be reduced with respect to the flow rate required by the engine. By reducing the injection amount per injection hole, the liquid film thickness along the inner wall of the injection hole is reduced, and the atomization degree of the injected fuel particles is further improved.

  That is, the fuel injection valve according to the present embodiment has a valve body for opening and closing the valve seat, and receives the operation signal from the control device to operate the valve body, so that the fuel is supplied to the valve body and the valve seat. This is a fuel injection valve that is injected from a plurality of injection holes provided in the injection hole plate attached to the valve seat opening on the downstream side of the valve seat after passing between the parts. A plurality of fuel chambers and an introduction portion for introducing fuel from the valve seat opening to the fuel chamber are formed in a form in which the upstream end surface of the nozzle hole plate is depressed, and the fuel chamber has a cylindrical cylindrical portion, It is comprised from the turning part, and the nozzle hole is opened in the center of a cylindrical part.

  The swivel portion surrounds substantially half of the outer periphery of the cylindrical portion, and the relationship is 0.3 ≦ W2 / W1 ≦ 0.7, where W1 is the width of the introduction portion and W2 is the width of the swivel portion. Further, the turning part is continuous with the introduction part because the outer periphery is in contact with the inner wall of the introduction part, and the terminal surface L of the outer peripheral part of the cylindrical part is the terminal part of the turning part. An angle θ formed by the end surface L and the central axis of the introduction portion is characterized by a relationship of 0 ° ≦ θ ≦ 45 °.

Embodiment 2. FIG.
FIG. 9 shows a recess 13a in the fuel injection valve 100 according to the second embodiment. The cylindrical portion 19 has a diameter D1. In order to create a homogeneous swirl flow, the flow 21 that directly enters the cylindrical portion 19 from the introduction portion 18 and the flow 22 that passes from the introduction portion 18 through the swivel portion 20 collide with the swirl flow formed in the cylindrical portion 19. It is desirable to smoothly flow into the cylindrical portion 19 without using it. That is, it is necessary to make the inflow region of each flow into the cylindrical portion 19 smaller than the radius D1 / 2 of the cylindrical portion.

  In the fuel injection valve 100 according to the present embodiment, as shown in FIG. 10, the region directly entering the cylindrical portion 19 from the introduction portion 18 has a width W1-W2, and the flow through the swivel portion 20 is the cylindrical portion 19. The region flowing into the region has a width W2. If each inflow region is made smaller than the radius D1 / 2 of the cylindrical part 19, each flow flows into the cylindrical part 19 without colliding with the swirl flow formed in the cylindrical part 19.

  Therefore, when the diameter of the cylindrical part 19 is D1, the width of the introduction part 18 is W1, and the width of the swivel part 20 is W2, each flow can be achieved by setting W1-W2 ≦ D1 / 2 and W2 ≦ D1 / 2. Can smoothly generate a swirl flow in the cylindrical portion 19 without colliding with the swirl flow formed in the cylindrical portion. Thereby, since the homogeneity of the swirl flow is improved, the atomization degree of the injected fuel particles is further improved.

Embodiment 3 FIG.
FIG. 11A shows a plan view of a recess 13a in the fuel injection valve according to the third embodiment. FIG. 11B shows a cross-sectional view of the recess 13a in the fuel injection valve according to the third embodiment. In the configuration of the first and second embodiments, since the flow that has flowed into the cylindrical portion directly enters the nozzle hole 14, fuel is injected in a state where the swirling is insufficient, and the liquid film may not be sufficiently thinned. There is sex. Therefore, in the third embodiment, the bottom surface of the cylindrical portion 19 is deeper than the bottom surfaces of the introduction portion 18 and the turning portion 20. As a result, the flow 21 that directly enters the cylindrical portion 19 from the introduction portion 18 and the flow 22 that passes from the introduction portion 18 through the swivel portion 20 flow toward the bottom surface of the cylindrical portion after flowing into the cylindrical portion, and are therefore drawn toward the injection hole. The flow is relaxed.

  FIG. 12 shows the flow of fuel generated in the recess 13a according to the present embodiment. In the figure, two fuel routes flowing from the introduction part 18 into the cylindrical part 19 and the swivel part 20 are displayed. As shown in the figure, the fuel flows into the nozzle hole after a sufficient swirling flow is formed in the cylindrical portion 19 by the two flows, so that the fuel liquid film formed on the inner wall of the nozzle hole is further thinned and injected. The degree of atomization of the generated fuel particles is further improved.

Embodiment 4
In the first to third embodiments, the introduction portion 18 has a radial linear shape with the center of the valve seat as a base point, but the same effect can be obtained even if the introduction portion 18 is changed to a curved shape without departing from the gist of the invention. I can do it. For example, in order to extend the introduction portion for the purpose of rectification, the same effect can be obtained with the shape of the refracted introduction portion. Specifically, as shown in FIG. 13, the introduction part 18 has a refracting part 18a.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

DESCRIPTION OF SYMBOLS 1 Drive circuit, 2 branch part, 3 center axis | shaft, 4 solenoid apparatus, 5 housing, 6 core, 7 coil, 8 armature , 9 plunger, 10 valve body, 11 valve main body, 12 valve seat, 12a valve seat sheet | seat part, 13 Injection hole plate, 14 injection hole, 15 ball, 16 compression spring, 17 fuel chamber, 18 introduction part, 19 cylindrical part, 20 swivel part, 21 flow, 22 flow, 100 fuel injection valve

Claims (5)

A plunger driven by a solenoid device;
A valve seat disposed downstream of the plunger and having an opening;
A radial depression having a branching part, an introduction part, a cylindrical part, and a swivel part is processed on the upstream side, and an injection hole plate having an injection hole opened on the downstream side of the cylindrical part, and
The introduction part has one end connected to the branch part and the other end connected to the cylindrical part and the turning part,
The swivel part is closed at the end surface circumscribing the cylindrical part after partially surrounding the cylindrical part,
The end surface of the swivel portion is inclined by an angle θ with respect to the central axis of the introduction portion,
This angle θ is in the range of 0 ° or more and 45 ° or less, and the ratio W2 / W1 of the width W2 of the swivel portion to the width W1 of the introduction portion is 0.3 or more and 0.7 or less. A fuel injection valve characterized by being within a range.   The radius of the cylindrical part is greater than or equal to the difference between the width W1 of the introduction part and the width W2 of the swivel part, and is greater than or equal to the width W2 of the swivel part. Item 4. The fuel injection valve according to Item 1.   3. The fuel injection valve according to claim 1, wherein a depth of the cylindrical portion is larger than a depth of the introduction portion and a depth of the swivel portion.   The fuel injection valve according to any one of claims 1 to 3, wherein the introduction portion has a linear shape.   The fuel injection valve according to any one of claims 1 to 3, wherein the introduction portion includes a refracting portion.

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