JPH0231570Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention has a plurality of injection fuel passages, which is used in a multi-valve engine having a plurality of intake valves.
This invention relates to the structure of an electromagnetically controlled fuel injection valve.

[Prior Art] An electromagnetically controlled fuel injection system is used in a dual intake valve engine that has two intake valves in one cylinder and has a branch intake passage section in which the intake passage is separated from each other by a partition wall near the intake valve. If adopted, if the intake passage is separated into two systems and the fuel injection valves of each system are installed in each branch intake passage, the number of installed fuel injectors and the injection system will be doubled compared to a normal engine. Therefore, a significant increase in costs is unavoidable.

On the other hand, a structure in which a single fuel injection valve is provided with multiple fuel injection holes is known (for example,
52-170123). In this device, the amount of fuel to be injected was measured through multiple fuel injection holes, but each fuel injection hole had to be precisely machined to achieve the specified injection amount. Compared to conventional valves with one hole, there are problems in that the machining time is more than twice as long and the machining method is difficult, resulting in increased costs.

In order to alleviate this problem, the applicant:
As shown in FIG. 6, there is one fuel injection hole 21 for metering the injected fuel, and a fuel injection hole 21 located downstream of the fuel injection hole 21 to branch the fuel from the fuel injection hole 21. A confluence section 2 of a plurality of injection fuel passages 22a and 22b injecting fuel from the outlet and an injection fuel passage located between the injection fuel passages and the fuel injection hole.
In the electromagnetically controlled fuel injection valve having the above-mentioned merging portion 23, each injected fuel passage axis passes through the top portion 25 of the fuel branching portion 24 that branches the fuel from the merging portion 23 into each injection fuel passage 22a, 22b. Core 26
A dimension between inner walls that is equal to or greater than the distance between the outer circumferences in each direction of each injection fuel passage cross section perpendicular to a and 26b.
D′ (see FIG. 7), and the cross-sectional area of the merging portion 23 in the direction perpendicular to the valve axis is set between the fuel injection hole 21 and the top 25 of the fuel branching portion 24. An electromagnetically controlled fuel injection valve with constant fuel pressure has been proposed (Utility Application No. 59-183167). In addition,
This type of electromagnetically controlled fuel injection valve was first developed in 1982.
It is also disclosed in Publication No. 123660.

In the electromagnetically controlled fuel injection valve proposed above,
Merging section 2 of injection fuel passages 22a and 22b located downstream of fuel injection hole 21 where metering is performed
As shown in Figure 7, the cross section of the opening to 3 is shaped like two ellipses overlapped, and a protruding part 27 is formed at the intersection, so to avoid fuel adhesion, the protruding part 27 is placed at the confluence. It was deleted when the 23rd was formed.

[Problem that the invention aims to solve] However, in this case, the following problem occurred. That is, since the existing proposal did not specify the depth of the merging portion 23, depending on the machining conditions or due to errors in machining accuracy, the top 2 of the fuel branch portion 24 may
5 does not necessarily have a sharp apex angle, and a flat portion 28 may be formed as shown in FIG. Left and right injection fuel passages 22a,
Fuel distribution to 22b deteriorates.

In order to solve these problems, this invention
The purpose is to ensure that a sharp edge-shaped portion remains at the top of the fuel branch, thereby adjusting the fuel injection angle and fuel distribution to the left and right passages as set values.

[Means for Solving the Problems] According to the present invention, this object is achieved by the following electromagnetically controlled fuel injection valve. That is, only one fuel nozzle hole for metering fuel is provided concentrically with the valve shaft; downstream of the fuel nozzle hole, there is an injection hole whose passage cross-sectional area is constant in the longitudinal direction of the passage. A plurality of fuel passages are provided and are inclined with respect to the valve axis such that an upstream portion of the injection fuel passage is closer to the valve axis than a downstream portion; Between the hole and the injection fuel passage,
The merging portion has a cross-sectional shape that envelops the opening cross section of the plurality of injected fuel passages to the merging portion, or has a larger cross-sectional shape, and is provided so that the cross-sectional shape is constant in the direction along the valve axis. a fuel branching section between the plurality of injection fuel passages that distributes the fuel to the plurality of injection fuel passages when the fuel is injected from the fuel injection hole and flies through the merging section; In the electromagnetically controlled fuel injection valve, the plurality of injected fuel passages are inclined with respect to the valve axis, and the fuel branch portion formed between the plurality of injected fuel passages is formed at the top thereof; having an upwardly pointed edge portion formed by overlapping intersections of the wall surfaces of the plurality of injection fuel passages;
The merging portion is formed so as to be separated upstream from a portion facing the fuel injection hole on the valve axis at the top of the fuel branching portion, and due to this separated formation. An electromagnetically controlled fuel injection valve characterized in that an edge portion that is not cut away in forming the merging portion is left at a top portion of the fuel branching portion at a portion facing the fuel injection hole.

[Operation] In the fuel injection valve having the above configuration, the merging portion is
Since it is formed upstream from the fuel nozzle hole facing portion of the top edge portion formed by the overlapping intersection of the wall surfaces of the injection fuel passage, the fuel nozzle hole facing portion of the top of the fuel branch portion is An edge portion always remains and no flat portion is formed at the top of the fuel branch.

Therefore, instead of the fuel being repelled by the flat top as in the prior art, the pointed top essentially distributes the fuel evenly among the plurality of injection fuel passages.

[Embodiments] Preferred embodiments of the electromagnetically controlled fuel injection valve according to the present invention will be described below with reference to the drawings.

1 to 5 show an electromagnetically controlled fuel injection valve according to the present invention.

First, FIG. 5 shows the entire electromagnetically controlled fuel injection valve 1. As shown in FIG. At the tip of the electromagnetically controlled fuel injection valve 1, one fuel injection hole 3 for metering the fuel from the fuel supply passage 2 is provided concentrically with the valve axis. In order to control
As shown in the figure, a seat portion 6 is constituted by a ball 4 and a curved inner wall surface 5.

The adapter 7 corresponds to the downstream side of the fuel injection hole 3.
As shown in FIG. 1, the adapter 7 is equipped with a plurality of (two in the illustrated example) which divides the fuel from the fuel nozzle hole 3 and injects it from the outlet.
injection fuel passages 8a and 8b having arbitrary cross-sectional shapes, but having a constant cross-sectional shape in the longitudinal direction of the passages;
A confluence portion 9 of the injection fuel passages is provided between the injection fuel passages 8a, 8b and the fuel injection holes 3. In this embodiment, the injection fuel passages 8a and 8b are formed to have a circular cross section. Injection fuel passages 8a, 8
b is inclined with respect to the valve shaft center such that the upstream portion thereof is closer to the valve shaft center than the downstream portion, and is formed between the injection fuel passages 8a and 8b on the downstream side of the confluence portion 9. The fuel branch part 10, which has an inverted V-shaped cross section, allows its axes 11a and 11b to be
is branched so that it has a predetermined opening angle α. The inclination of the injected fuel passages 8a, 8b with respect to the valve axis (if there are two injected fuel passages 8a, 8b, the inclination angle is α/2) is determined by
formed by the overlapping intersection of the walls of the injection fuel passages 8a, 8b (therefore, at least
(formed to have a ridge line of a certain length), with an upwardly pointed edge formed;
It is determined.

As shown in FIGS. 1 and 4, the merging section 9 is a fuel branching section top 1 at an edge section specified by a ridge line where the wall surfaces of the injection fuel passages 8a and 8b intersect.
2, it is formed at a position spaced apart upstream from the part facing the fuel injection hole 3 on the valve axis. 1st
In the figure, l indicates this distance. Confluence part 9
are the axes 11a, 1 of each injection fuel passage 8a, 8b.
The opening cross section A of each injected fuel passage 8a, 8b to the confluence part 9 in a plane perpendicular to In the case of Fig. 3), it is formed to have a cross-sectional shape D, that is, a cross-sectional shape that envelopes the opening cross-section A or is larger than that. The passage cross-sectional area of the merging portion 9 is constant in the direction along the valve axis on the outer peripheral wall surface of the merging portion 9. A cross section of the merging portion 9 in a plane perpendicular to the injection valve axis includes a cross section of an extension of each of the injected fuel passages 8a and 8b.

The confluence section 9 and fuel branch section 1 formed in this way
0, when there are two injection fuel passages 8a and 8b, the top part 12 of the fuel branch part 10 extends from the part facing the fuel nozzle hole 3 on the valve shaft center to both sides as shown in FIG. It gradually extends upward while curving towards the
Both ends terminate at the bottom surface 13 of the confluence section 9. The merging portion 9 is formed in the top portion 12 of the fuel branching portion 10 so as to be spaced upstream from the fuel injection hole opposing portion of the top portion 12. There is a sharp edge facing upwards that is left in place to avoid interference with the surface.

The cross-sectional shape of the passage of the merging portion 9 may be any shape as long as the above conditions are satisfied. The second example is
Figures 3 and 3 show the shape taken along the - cross section in Figure 1.

In the example shown in FIG.
The outer diameter pitch of the cross section of the opening of a, 8b to the merging portion 9a is greater than or equal to H, that is, D≧H.

In the example shown in FIG. 3, the merging portion 9b is formed as a passage with a track-shaped cross section, the dimension D on the major axis side is D≧H as described above, and the width W on the minor axis side is the injected fuel passage 8a, 8b. It is formed to have dimensions equal to or larger than each diameter of the The merging portions 9a and 9b are formed by counterboring from the top of the adapter 7.

Next, the operation of the electromagnetically controlled fuel injection valve configured as described above will be explained.

The fuel sent from the fuel supply passage 2 through the seat portion 6 is first metered by one fuel injection hole 3 to a set flow rate. The metered fuel travels through the junction 9 and is distributed to each injection fuel passage 8a, 8b at the top 12 of the fuel branch 10. The distributed fuel is injected as fuel spray from the exits of the injection fuel passages 8a and 8b, respectively.

The passage cross-sectional area of the merging portion 9 is the same as that of each injection fuel passage 8.
Since the cross-sections of the openings of a and 8b to the merging portion 9 are envelope-shaped or larger, and the passage cross-sectional area is constant in the flow direction, the volume of the merging portion 9 is ensured to be sufficiently large. Therefore, the fuel does not adhere to the wall surface at the merging section 9, and the flight of the fuel at the merging section 9 becomes stable. Further, when the fuel flies through the confluence section 9 having a constant cross-sectional area, the fuel reaches the fuel branch section 10 without being subject to large fluctuations in flow. Since an edge-shaped portion is left on the top portion 12 of the fuel branch portion 10 facing the fuel nozzle hole, it will not be repelled by hitting a flat surface, and will smoothly and evenly achieve the desired set amount. It is distributed to each injection fuel passage 8a, 8b in a set direction.

Furthermore, when the flow at the merging portion 9 becomes stable, there will be no adverse effect on the upstream side from the merging portion 9, that is, the fuel injection hole 3, and the metering accuracy in the fuel injection hole 3 will be improved.

[Effect of the invention] Therefore, according to the invention, the injection fuel passage is formed with a pointed edge toward the upstream side at the top of the fuel branch part by the overlapping intersection of the injection fuel passage wall surfaces with respect to the valve shaft core. Since the merging part is formed at an angle upstream from the part facing the fuel nozzle hole at the top of the fuel branch part, the edge part is always formed at the part facing the fuel nozzle hole at the top of the branch part. This makes it possible to equalize and stabilize the distribution of fuel from the merging section to each injection fuel passage, and also to stabilize the direction of fuel branching. The effect is that the accuracy of the amount and direction of fuel injected toward the intake passage can be improved.

Furthermore, by stabilizing the flight at the fuel merging section, the accuracy of metering at the fuel injection hole can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the tip of an electromagnetically controlled fuel injection valve according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the - line of FIG. FIG. 4 is a cross-sectional view of a portion corresponding to the - line in FIG. 1 near the merging portion of an electromagnetically controlled fuel injection valve according to two embodiments; FIG. 5A is a sectional view of the entire electromagnetically controlled fuel injection valve in FIG. 1, FIG. 5B is a front view of the tip of the electromagnetically controlled fuel injection valve in FIG. 5A, and FIG. 6 is a sectional view of the light end of the previously proposed fuel injection valve, FIG. 7 is a sectional view taken along the - line in FIG. 6, and FIG. . DESCRIPTION OF SYMBOLS 1...Electromagnetically controlled fuel injection valve, 2...Fuel supply passage, 3...Fuel injection hole, 6...Seat portion, 7...
Adapter, 8a, 8b... Injection fuel passage, 9, 9
a, 9b... Merging section, 10... Fuel branching section, 11
a, 11b...Axle core (injection fuel passages 8a, 8b
), 12...Top of the fuel branch, 13...Bottom surface of the merging part, H...Outer diameter pitch of the opening cross section of the injection fuel passages 8a, 8b to the merging part 9, D...Passway diameter of the merging part, W: Passage width at the merging section.

Claims (1)

[Claims for Utility Model Registration] Only one fuel injection hole for metering fuel is provided concentrically with the valve shaft; downstream of the fuel injection hole, the cross-sectional area of the passage is in the longitudinal direction of the passage. A plurality of injection fuel passages are provided, each of which has a constant angle, and is inclined with respect to the valve axis such that an upstream portion of the injection fuel passage is closer to the valve axis than a downstream portion of the injection fuel passage. between the fuel nozzle hole and the injection fuel passage;
The merging portion is provided with a cross-sectional shape that envelops or has a larger cross-sectional shape that surrounds the cross-section of the opening of the plurality of injected fuel passages to the merging portion, and that the cross-sectional shape is constant in a direction along the valve axis. and; a fuel branching section is provided between the plurality of injection fuel passages for distributing the fuel to the plurality of injection fuel passages when the fuel is injected from the fuel nozzle hole and flies through the merging section. In an electromagnetically controlled fuel injection valve, the plurality of injected fuel passages are inclined with respect to the valve axis, and the fuel branch portion formed between the plurality of injected fuel passages is at the top thereof. The plurality of injection fuel passages are defined to have upwardly pointed edges formed by overlapping intersections of the wall surfaces of the plurality of injection fuel passages; An edge portion is formed on the core so as to be separated from a portion facing the fuel nozzle hole on the upstream side, and as a result of this separated formation, an edge portion that is not scraped off in the formation of the merging portion is provided at the top of the fuel branch portion. An electromagnetically controlled fuel injection valve characterized in that: is left at a portion facing the fuel injection hole.