WO2019207753A1

WO2019207753A1 - Fuel injection valve

Info

Publication number: WO2019207753A1
Application number: PCT/JP2018/017136
Authority: WO
Inventors: 啓祐伊藤; 章男新宮; 範久福冨; 恭輔渡邉; 学平井; 宗実　毅
Original assignee: 三菱電機株式会社
Priority date: 2018-04-27
Filing date: 2018-04-27
Publication date: 2019-10-31
Also published as: CN111989480B; CN111989480A; PH12020551753A1; JPWO2019207753A1

Abstract

A fuel injection valve (100) is provided with: a valve seat (12) having a valve-seat seat section (12a) and a valve-seat opening section (12b); a valve body (10) brought into contact with the valve-seat seat section (12a) of the valve seat (12) to prevent the outflow of fuel from the valve-seat opening section (12b) and separated from the valve-seat seat section (12a) to allow the outflow of the fuel from the valve-seat opening section (12b); and injection hole plate (13) affixed to the downstream end surface of the valve seat (12) and having a plurality of injection holes (14) for ejecting to the outside the fuel flowing out from the valve-seat opening section (12b). The upstream end surface of the injection hole plate (13) has a swirl chamber (18) to which the injection holes (14) are open and connected and which applies a swirling force to fuel, and a fuel passage (17) which introduces fuel into the swirl chamber (18). The swirl chamber (18) and the fuel passage (17) comprise side walls (20) having a tapered shape which widens toward the upstream side, and the downstream end surface of the injection hole plate (13) has a recess (30) in a region including the swirl chamber (18) and the fuel passage (17).

Description

Fuel injection valve

The present application 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 and the like have been tightened, atomization of fuel spray injected from a fuel injection valve has been demanded, and various studies have been made regarding methods for atomizing using a swirl flow Has been made.

In Patent Document 1, a plunger driven by a solenoid device, a valve seat disposed on the downstream side thereof, having an opening, a radial depression having a branching portion, an introducing portion, a cylindrical portion, and a swiveling portion are upstream. Of the valve main body, which is a tip part of the fuel injection valve, having an injection hole plate in which an injection hole opens on the downstream side of the cylindrical portion, and the injection hole plate is coupled to the downstream side of the valve seat. A structure to be mounted inside is described.

WO2017 / 060945

In general, a fuel injection valve attached to an intake passage upstream of the combustion chamber is arranged close to the combustion chamber to reduce fuel adhesion to the intake passage in order to more accurately control the amount of fuel entering the combustion chamber. It is desirable.

The above-described combustion injection valve of Patent Document 1 has a problem when placed close to the combustion chamber. That is, the valve body that is the tip part of the fuel injection valve has a large surface area that is exposed to the high-temperature gas blown back from the combustion chamber, so that it tends to be hot, and the injection hole plate or valve seat attached inside the valve body is the valve body. Heat is transferred from the radial end close to the center toward the center.

Since the thickness of the nozzle hole plate of Patent Document 1 is uniform except for the radial depression formed on the upstream side, heat is easily transmitted from the end of the nozzle hole plate to the vicinity of the nozzle hole in the central part, There is a problem that the temperature becomes high and residual gasoline in the nozzle hole adheres to the inner surface of the nozzle hole, which may cause deterioration in atomization of the spray or change in the injection flow rate.

The present application discloses a technique for solving the above-described problems. The purpose of the present application is to form an injection hole plate shape in which the injection hole portion is not easily heated even when the fuel injection valve is arranged close to the combustion chamber. Thus, an object of the present invention is to provide a fuel injection valve in which the spray characteristic or the flow rate characteristic is maintained in a good state.

A fuel injection valve disclosed in the present application includes a valve seat having a valve seat portion and a valve seat opening, and an outflow of fuel from the valve seat opening in contact with the valve seat portion of the valve seat A valve body that is separated from the valve seat and allows fuel to flow out of the valve seat opening, and is fixed to the downstream end face of the valve seat and flows out of the valve seat opening. A fuel injection valve having a plurality of injection holes for injecting the fuel to the outside, wherein the injection holes are opened on the upstream end face of the injection hole plate so as to communicate with the fuel. A swirl chamber that imparts fuel to the swirl chamber, and the swirl chamber and the fuel passage are configured by side walls having a tapered shape that widens toward the upstream side. The swivel chamber and the fuel passage are included in the downstream end surface And it has a recess to pass.

According to the fuel injection valve disclosed in the present application, a high temperature in the vicinity of the injection hole can be suppressed, and the fuel temperature in the swirl chamber or the fuel passage can be reduced, and the spray characteristics or the flow characteristics are maintained in a good state. The fuel injection valve which can be obtained can be obtained.

[Correction based on Rule 91 10.05.2018]
1 is a cross-sectional view showing a fuel injection valve according to Embodiment 1. FIG. FIG. 2 is a cross-sectional view (a) showing a tip portion of the fuel injection valve according to the first embodiment and a cross-sectional view (b) taken along line AA of the cross-sectional view (a). FIG. 6 is an enlarged view (a) showing an upstream end face of the nozzle hole plate in the fuel injection valve according to the first and second embodiments, and a sectional view (b) taken along the line BB of the enlarged view (a). It is sectional drawing (a) which shows the front-end | tip part in the fuel injection valve by

Embodiment

1, 3, and the figure (b) seen from the arrow S1 direction of the downstream of the nozzle hole plate in a fuel injection valve. It is sectional drawing (a) which shows the front-end | tip part in the fuel injection valve by Embodiment 4, and the figure (b) seen from the arrow S2 direction of the downstream of the nozzle hole plate in a fuel injection valve. It is sectional drawing (a) which shows the front-end | tip part in the fuel injection valve by Embodiment 5, and the figure (b) seen from the arrow S3 direction of the downstream of the nozzle hole plate in a fuel injection valve. It is sectional drawing (a) which shows the front-end | tip part in the fuel injection valve by Embodiment 6, and the figure (b) seen from the arrow S4 direction of the downstream of the nozzle hole plate in a fuel injection valve. FIG. 10 is an enlarged view (a) showing an upstream end face of a nozzle hole plate in a fuel injection valve according to a seventh embodiment, and a sectional view (b) taken along line CC of the enlarged view (a).

Embodiment 1 FIG.
1 is a side view showing a fuel injection valve according to Embodiment 1. FIG. 2A is a cross-sectional view showing a tip portion of the fuel injection valve according to Embodiment 1, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A.

100 indicates a fuel injection valve. 4 is a solenoid device, 5 is a metal brate which is a yoke part of the magnetic circuit, a cylindrical core 6 which is a fixed core part of the magnetic circuit, and 7 is a coil wound around a bobbin 1 disposed on the outer periphery of the core 6. , 8 is a cylindrical armature whose arm upper end surface 8b is in contact with and separated from the lower end surface of the core 6 and is a movable iron core portion of a magnetic circuit, and has a sliding surface 8a that slides in a valve holder 11 described later. The armature 8 is slidable in the axial direction within the valve holder 11. Reference numeral 9 denotes a valve device. The valve device 9 includes a valve body 10, a valve holder 11, and a valve seat 12. In addition, the metal braid 5 is arrange | positioned ranging over the outer peripheral surface of the core 6, and the outer peripheral surface of the valve holder 11, and is being fixed by welding.

The upstream end of the valve holder 11 is welded after being pressed into the outer periphery of the core 6. The cylindrical armature 8 is pressed into the upstream end of the valve body 10 and then welded, so that the armature 8 and the valve body 10 move integrally in the axial direction. A nozzle hole plate 13 is joined to the lower end surface of the valve seat 12 by welding at a welded portion 50, and the valve seat 12 and the nozzle hole plate 13 are integrally formed and attached to the inside of the downstream end of the valve holder 11. . The nozzle hole plate 13 is provided with a plurality of nozzle holes 14 penetrating in the plate thickness direction.

A ball 15 having a chamfered portion 15 a is fixed to the downstream end portion of the valve body 10, and the ball 15 is seated and separated from the valve seat portion 12 a of the valve seat 12. A compression spring 16 that presses the valve body 10 in a direction in which the ball 15 is pressed against the valve seat portion 12 a of the valve seat 12 is inserted into the cylindrical core 6. An adjuster 2 for adjusting the load of the compression spring 16 is fixed in the cylindrical core 6. Further, the filter 3 is inserted into the upper end portion of the cylindrical core 6 serving as a fuel introduction portion. The valve holder 11, the core 6, the coil 5, and the metal plate 5 are integrally formed in the resin housing 22. The resin housing 22 is provided with a connector portion 22a, and a terminal 23 electrically connected to the coil 5 is drawn into the connector portion 22a.

On the upstream end face of the nozzle hole plate 13, there is a swirl chamber 18 that opens and communicates with the nozzle hole 14, and a fuel passage 17 that introduces fuel into the swirl chamber 18. The fuel passage 17 includes a side wall 20 having a tapered shape that widens toward the upstream side, and a recess 30 is formed in a region including the swirl chamber 18 and the fuel passage 17 on the downstream end face of the nozzle hole plate 13. The nozzle hole 14 is provided near the center of the swirl chamber 18. The fuel passage 17 communicates with the valve seat opening 12b.

Next, the operation will be described. When an operation signal is sent from the engine control device to the drive circuit of the fuel injection valve 1, a current is passed through the coil 7 of the fuel injection valve 1, and the arm 8, the core 6, the housing 5, and the valve holder 11 are configured. When magnetic flux is generated in the magnetic circuit, the armature 8 is attracted to the core 6 side, and when the valve body 10 that is integral with the armature 8 is separated from the valve seat portion 12a and a gap is formed, the fuel is supplied to the valve body 10. From the chamfered portion 15a of the ball 15 welded to the front end portion of the valve 15 through the gap between the valve seat portion 12a and the valve body 10, the fuel is injected from the plurality of nozzle holes 14 into the intake passage of the engine.

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 7 is stopped, the magnetic flux in the magnetic circuit is reduced, and the valve body 10 is The gap between the valve element 10 and the valve seat portion 12a is closed by the compression spring 16 pushed in the valve closing direction, and fuel injection is completed. The valve body 10 slides with the guide portion on the inner peripheral surface of the valve holder 11 on the sliding surface 8 a of the armature 8, and the armature upper surface 8 b of the armature 8 abuts on the bottom surface of the core 6 in the valve open state.

In the first embodiment, as shown in FIGS. 2 (a), 2 (b), 3 (a), and 3 (b), the swivel force is imparted to the fuel by recessing the upstream end face of the nozzle hole plate 13. A plurality of swirl chambers 18 are formed. The nozzle holes 14 are respectively provided in the vicinity of the center of the swirl chamber 18. Corresponding to the swirl chamber 18, a fuel passage 17 for introducing fuel into the swirl chamber 18 is provided. The fuel passage 17 communicates with the valve seat opening 12b.

Thus, the fuel that has flowed from the valve seat opening 12b into the swirl chamber 18 through the fuel passage 17 flows into the nozzle hole 14 while generating a swirl flow. Since the swirl flow is also maintained inside the nozzle hole 14, a thin liquid film is formed along the inner wall of the nozzle hole 14, and the thin liquid film is injected into the hollow cone shape from the nozzle hole 14 to form fine fuel particles. Is promoted.

When the fuel injection valve 1 is disposed close to the combustion chamber, the valve holder 11 that is the tip part of the fuel injection valve 1 has a large surface area that is exposed to the high-temperature gas blown back from the combustion chamber, so that the temperature tends to be high. 11 is transmitted from the end of the nozzle hole plate 13 attached to the inside of the nozzle 11 or the outer peripheral part of the valve seat 12 to the central part of the nozzle hole plate 13, and the vicinity of the nozzle hole 14 becomes high temperature. There is concern about deterioration of spray atomization or changes in the injection flow rate due to being fixed to the inner surface of the injection hole 14. Further, the fuel in the swirl chamber 18 and the fuel passage 17 becomes high temperature, and there is a concern that the atomization of the spray may be deteriorated or the injection flow rate may be changed due to cavitation.

Therefore, in the first embodiment, the side wall 20 forming the swirl chamber 18 and the fuel passage 17 is formed in a tapered shape that widens toward the upstream side. Accordingly, since the surface area of the side wall 20 in contact with the fuel is increased as compared with the case where the shape is not tapered as in Patent Document 1, the cooling effect by the fuel is enhanced, and the temperature in the vicinity of the injection hole 14 can be reduced.

Further, as shown in FIGS. 4A and 4B, the projection is projected on the downstream end face of the nozzle hole plate 13 when the vertical direction of the downstream end face is viewed from the downstream side of the nozzle hole plate 13 of the arrow S1. A recess 30 is provided in a region including the swirl chamber 18 and the fuel passage 17 to make the plate thickness of the nozzle hole plate 13 thinner than the end of the nozzle hole plate 13.

As a result, heat transfer from the end of the injection hole plate 13 attached to the inside of the valve holder 11 to the vicinity of the injection hole 14 can be reduced, so that even when the fuel injection valve is arranged close to the combustion chamber, the injection Since the high temperature in the vicinity of the hole 14 is suppressed, it becomes possible to prevent the residual gasoline from adhering to the inner surface of the injection hole 14, and the fuel temperature in the swirl chamber 18 or the fuel passage 17 can also be reduced. It is possible to suppress the occurrence of spraying, and it is possible to suppress the deterioration of spray atomization or the change in the injection flow rate.

Embodiment 2. FIG.
3A is an enlarged view showing the upstream end face of the nozzle hole plate in the fuel injection valve according to the second embodiment, and FIG. 3B is a BB line in FIG. 3A of the second embodiment. FIG.

When the fuel passage 17 and the injection hole 14 are projected on a plane perpendicular to the central axis of the fuel injection valve 1, the width and depth of the bottom of the fuel passage 17 are H and V, respectively, and the inclination angle of the side wall 20 with respect to the depth direction. Is θ, and the distance from the central axis of the bottom of the fuel passage 17 to the center of the injection hole 14 is L, a relational expression of H / 2 + V · tan θ <L holds.

Thereby, even if the side wall 20 forming the fuel passage 17 has a tapered shape that widens toward the upstream side, the fuel that is rectified in the fuel passage 17 and flows into the swirl chamber 18 becomes difficult to directly enter the injection hole 14. Therefore, the swirl flow generated inside the nozzle hole 14 is not weakened and atomization of the spray can be maintained.

Embodiment 3 FIG.
FIG. 4A is a cross-sectional view showing the tip of the fuel injection valve according to the third embodiment, and FIG. 4B is a view from the direction of arrow S1 on the downstream side of the nozzle hole plate in the fuel injection valve according to the third embodiment. FIG.

The nozzle hole plate 13 is welded to the downstream side of the valve seat 12 in a ring shape, and the welded portion 50 is provided on the outer side in the radial direction from the concave portion 30 provided on the downstream end face of the nozzle hole plate 13. It is possible to suppress thermal deformation caused by welding rather than providing it at a portion where the plate thickness is thin.

Therefore, there is no gap or the like due to thermal deformation between the valve seat 12 and the nozzle hole plate 13, and the fuel normally flows in the fuel passage 17 and the swirl chamber 18, so that a good swirl in the nozzle hole 14 is achieved. Since the flow can be generated, it is possible to suppress the deterioration of spray atomization or the change in the injection flow rate.

Further, during fuel injection, a load due to fuel pressure is applied to the nozzle hole plate 13, and stress concentration occurs particularly in the vicinity of the welded part 50, but the welded part 50 is provided in a thick part of the nozzle hole plate 13. Therefore, the strength of the nozzle hole plate 13 can be increased and the durability can be improved as compared with the case where it is provided in the thin portion in the recess 30.

Embodiment 4 FIG.
FIG. 5A is a cross-sectional view showing the tip of the fuel injection valve according to the fourth embodiment, and FIG. 5B is a view from the direction of arrow S2 on the downstream side of the nozzle hole plate in the fuel injection valve according to the fourth embodiment. FIG.

A part of the fuel injected from the nozzle hole 14 adheres to the vicinity of the outlet of the nozzle hole 14, but the side wall 20 of the recess 30 provided on the downstream end face of the nozzle hole plate 13 as in the first embodiment described above. However, when it is formed perpendicular to the bottom surface of the recess 30, the attached fuel near the outlet of the injection hole 14 is difficult to spread in the radial direction of the injection hole plate 13 and is difficult to peel off from the downstream end face. As a result, the adhering fuel is fixed by the surrounding high-temperature gas and closes the outlet portion of the injection hole 14, and there is a concern that the atomization of the spray is deteriorated or the injection flow rate is changed.

Therefore, in the fourth embodiment, the side wall 40 that forms the recess 30 provided on the downstream end face of the nozzle hole plate 13 is provided in a tapered shape that widens toward the downstream side, as compared with the first embodiment described above.

As a result, even if a part of the fuel injected from the nozzle hole 14 adheres to the vicinity of the outlet of the nozzle hole 14, it easily spreads in the radial direction of the nozzle hole plate 13 and easily peels from the downstream end face, and the adhered fuel adheres. As a result, the outlet of the nozzle hole 14 is not blocked, and deterioration of spray atomization or change in the injection flow rate can be suppressed.

Embodiment 5. FIG.
6 (a) is a cross-sectional view showing the tip of the fuel injection valve according to the fifth embodiment, and FIG. 6 (b) is a view from the direction of arrow S3 on the downstream side of the nozzle hole plate in the fuel injection valve according to the fifth embodiment. FIG.

In the fifth embodiment, when the concave portion 30 provided on the downstream end face of the nozzle hole plate 13 is viewed from the downstream side of the nozzle hole plate 13 indicated by the arrow in the vertical direction of the downstream end face in the fourth embodiment described above. It is provided in a portion other than the region including the swirl chamber 18 and the fuel passage 17 to be projected.

Thus, only the swirl chamber 18 and the fuel passage 17 on the downstream end face of the nozzle hole plate 13 have a shape that rises to the downstream side with respect to the bottom surface of the recess 30, so that injection is further performed than in the above-described fourth embodiment. Part of the fuel is less likely to stay in the vicinity of the outlet of the nozzle hole 14 and easily peels off from the downstream end face, so that the outlet part of the nozzle hole 14 is not blocked due to the adhering fuel adhering. A change in flow rate can be suppressed.

Embodiment 6 FIG.
FIG. 7A is a cross-sectional view showing the tip of the fuel injection valve according to the sixth embodiment, and FIG. 7B is a view from the direction of arrow S4 on the downstream side of the nozzle hole plate in the fuel injection valve according to the sixth embodiment. FIG.

In the first and fourth embodiments described above, when the concave portion 30 is provided in a wide range of the downstream end face of the nozzle hole plate 13, the thickness of the nozzle hole plate 13 is reduced in a wide range, and durability due to insufficient strength of the nozzle hole plate 13. There is concern about the deterioration of sex.

Therefore, in the sixth embodiment, the swirl chamber 18 and the fuel passage 17 projected when the vertical direction of the downstream end surface is viewed from the downstream side of the nozzle hole plate 13 as the concave portion provided on the downstream end surface of the nozzle hole plate 13. Are provided at two locations, a concave region 30a1 including the concave region 30b1 on the radially outer side.

In this way, by providing a plurality of concave regions 30a1 and 30b1 on the downstream end face of the nozzle hole plate 13 and forming a concave and convex shape that is difficult to deform, the nozzle hole plate 13 is compared with the case where one concave portion is provided in a wide range. While maintaining the strength of the nozzle hole 13, it is possible to reduce the thermal conductivity from the end of the nozzle hole plate 13 to the nozzle hole 14 part to suppress the high temperature of the nozzle hole 14 part. A change in flow rate can be suppressed.

Embodiment 7 FIG.
FIG. 8A is an enlarged view showing the upstream end face of the injection hole plate in the fuel injection valve according to the seventh embodiment, and FIG. 8B is a CC line in FIG. 8A of the seventh embodiment. FIG.

In contrast to the second embodiment described above, the side wall 20 forming the fuel passage 17 is formed only on the side 17a farther away from the injection hole 14 and has a taper shape extending toward the upstream side on the side 17b closer to the injection hole 14. Therefore, the fuel that is further rectified in the fuel passage 17 and flows into the swirl chamber 18 is difficult to enter directly into the nozzle hole 14, so that the swirl flow generated in the nozzle hole 14 is not weakened and atomization of the spray is prevented. Can be maintained.

Although this application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more embodiments may be applied to particular embodiments. The present invention is not limited to this, and can be applied to the embodiments alone or in various combinations.
Accordingly, countless variations that are not illustrated are envisaged within the scope of the technology disclosed herein. For example, the case where at least one component is deformed, the case where the component is added or omitted, the case where the at least one component is extracted and combined with the component of another embodiment are included.

The present application is suitable for realizing a highly reliable fuel injection valve capable of suppressing deterioration of spray atomization or change in injection flow rate.

100 fuel injection valve, 9 valve device, 10 valve element, 11 valve holder, 12 valve seat, 12a valve seat portion, 12b valve seat opening, 13 injection hole plate, 14 injection hole, 17 fuel passage, 18 swirl chamber, 20 side walls, 30 recesses, 40 side walls, 50 welds

Claims

A valve seat having a valve seat and a valve seat opening;
The valve seat is in contact with the valve seat portion to prevent fuel from flowing out of the valve seat opening, and is separated from the valve seat portion to allow fuel to flow out of the valve seat opening. A valve body to
A fuel injection valve comprising: a nozzle plate fixed to a downstream end surface of the valve seat, and having a plurality of nozzle holes for injecting the fuel flowing out from the valve seat opening to the outside;
An upstream end face of the nozzle hole plate, the nozzle hole is opened and communicated with each other, and a swirling chamber that imparts a swirling force to the fuel; and a fuel passage that introduces fuel into the swirling chamber;
The swirl chamber and the fuel passage are configured by side walls having a tapered shape that widens toward the upstream side,
A fuel injection valve having a recess in a region including the swirl chamber and the fuel passage on a downstream end face of the nozzle hole plate.
When the fuel passage and the injection hole are projected on a plane perpendicular to the central axis of the fuel injection valve, the width of the bottom of the fuel passage is H, the depth of the bottom of the fuel passage is V, The relationship of H / 2 + V · tan θ <L is established, where θ is an inclination angle with respect to the depth direction, and L is a distance from the central axis of the bottom of the fuel passage to the center of the nozzle hole. The fuel injection valve according to 1.
3. The fuel injection valve according to claim 1, wherein the nozzle hole plate is welded to a downstream side of the valve seat, and the concave portion is provided on an inner peripheral side with respect to a welded portion.
The fuel injection valve according to any one of claims 1 to 3, wherein the concave portion is constituted by a side wall having a tapered shape spreading toward the downstream side.
5. The fuel according to claim 1, wherein the recess is provided in a portion other than the swirl chamber and the fuel passage projected onto a downstream end surface of the nozzle hole plate. Injection valve.
The fuel injection valve according to any one of claims 1 to 5, wherein a plurality of the recesses are provided on a downstream end surface of the nozzle hole plate.
The fuel injection valve according to any one of claims 1 to 6, wherein the side wall forming the fuel passage has a tapered shape that widens toward the upstream side only on the side far from the nozzle hole. .