JPH04350362A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To stabilize the performance of a multiple intake engine by improving the machining accuracy of branch holes and a fuel measuring orifice in a multihole nozzle type fuel injection valve. CONSTITUTION:A nozzle part 17, provided with plural branch holes 18, 19 for branching fuel having passed a fuel measuring orifice 35, is formed by injection molding. A wedge type center wall part 20 between the branch holes 18, 19 for regulating the branched direction of fuel is formed into an angle of high accuracy due to this injection molding, so that constant fuel without dispersion can be distributed to each intake valve. In addition, the fuel measuring orifice 35 is a through hole bored in a plate body 34 by continuous precision machining such as precision punching so as to obtain the expected preceding flow without dispersion.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve, and more particularly to a multi-hole nozzle type fuel injection valve used in a dual-intake engine.

0002

2. Description of the Related Art A dual-intake engine is an engine that has a plurality of (usually two) intake valves in each cylinder. For such engines, one is known in which fuel is distributed and injected from one fuel injection valve toward a plurality of intake valves of each cylinder. This is a so-called multi-hole nozzle type fuel injection valve, which has the advantage of being able to reduce costs by half compared to the case where a normal (single-hole nozzle type) fuel injection valve is provided for each intake valve of each cylinder. A typical multi-nozzle fuel injection valve includes a plurality of branch holes downstream of a fuel metering orifice at the tip of a valve body housing for branching injected fuel at a predetermined angle toward a plurality of intake valves of each cylinder. Conventionally, a disk-shaped plate with a plurality of branch holes drilled at a desired angle by drilling or electric discharge machining was attached as a needle to the distal end surface of the valve body housing. Also,
As for the fuel metering orifice, a through hole is also bored in the center of the tip surface of the valve body housing by drilling or electric discharge machining.

0003

[Problem to be Solved by the Invention] However, it is extremely difficult to drill multiple branch holes at precise angles (directions) from the branch point by drilling, electrical discharge machining, etc. This causes variations in the fuel distributed to each intake valve, which may result in instability of engine performance. Furthermore, it is difficult to accurately drill a through hole (fuel metering orifice) with a predetermined diameter in the center of the tip surface of the valve body housing by drilling or electrical discharge machining, and due to machining errors, the full opening flow rate of the valve This could lead to errors in the engine performance, leading to instability in engine performance. The present invention has been made in view of these problems, and improves the machining accuracy of branch holes for branching fuel in multiple directions (towards multiple intake valves of each cylinder), thereby improving A first object of the present invention is to provide a fuel injection valve that stabilizes engine performance. A second object of the present invention is to provide a fuel injection valve that improves the machining accuracy of the fuel metering orifice to eliminate errors in the fully open flow rate, thereby stabilizing the performance of a dual intake engine.

0004

[Means for Solving the Problems] In order to achieve the above-mentioned first object, a first fuel injection valve of the present invention includes a fuel metering orifice in a fuel injection valve that injects fuel in a plurality of directions. The nozzle part has a plurality of branching holes for branching the passing fuel into a plurality of directions, and is formed by injection molding. In order to achieve the second purpose above,
A second fuel injection valve of the present invention is a fuel injection valve in which a nozzle portion having a plurality of branch holes for branching fuel passing through a fuel metering orifice in a plurality of directions is attached to the tip of a valve body housing. A plate member having a through hole as a fuel metering orifice is disposed between the nozzle portion and the valve body housing. Further, in the second fuel injection valve, in order to prevent fuel from leaking to the outside of the valve from the gap between the plate body and the valve body housing or the main body housing, the nozzle portion facing the plate body may be A groove is formed on the surface for guiding fuel from the outer peripheral edge of the plate to the branch hole.

[0005]

[Operation] In the first fuel injection valve, since the porous nozzle part is a resin molded product or a sintered product by injection molding,
The processing accuracy of the branch holes is high, and in particular, the wedge-shaped central wall between the branch holes, which defines the direction of fuel branching, is formed at a highly precise angle, allowing for uniform distribution of fuel to each intake valve. It can be performed. In the second fuel injection valve, the through-hole in the plate body formed by continuous precision machining such as precision press punching functions as a fuel metering orifice, so that a desired full-open flow rate without variation can be obtained. In the second fuel injection valve, if a groove is formed on the surface of the nozzle portion facing the plate body to guide fuel leaking from the outer periphery of the plate body to the branch hole, the plate body and the valve body housing may Even if fuel leaks from the gap, the leaked fuel is guided to the branch hole through the groove in the nozzle part, so it will not leak to the outside of the valve.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing the main parts of a fuel injection valve according to a first embodiment. In this fuel injection valve, a conventional fuel metering orifice 11 and a valve seat 12 are formed at the tip of a valve body housing 10, and a valve body 14 is accommodated in a valve chamber 13 so as to be movable in the axial direction. The rod portion 14a of the valve body 14 is connected to a movable iron core (not shown). 1
5 is a stopper plate for regulating the movement of the valve body 14, and 16 is a main body housing that constitutes the casing of the entire valve. A nozzle portion 17 is provided on the distal end surface of the valve body housing 10.
The body housing 16 is attached and fixed by caulking at the leading edge thereof. This nozzle part 17 has two branch holes 18,
19 are provided, the wedge-shaped tip of the central wall 20 between these branch holes facing the center of the fuel metering orifice 11. This nozzle portion 17 is a resin molded product or a sintered product formed by injection molding.

FIG. 2 shows an example of manufacturing the nozzle section 17. As shown in FIG. 2A, molding material is injected and filled into the cavity 22 in the mold 21 through a sprue 23 from an injection machine (not shown). After cooling and solidifying, the mold 21 is removed and the molded product of the nozzle portion 17 is taken out, as shown in FIG. 2(B). In the case of a sintered product, the nozzle portion 17 is then completed through a firing process.

As described above, in this embodiment, the two-hole nozzle part 17 is molded by injection molding, so that the wedge angle of the central wall part 20, which defines the branching direction of the fuel, is precisely formed at a predetermined angle. be able to.

FIG. 3 is a sectional view showing a modification of the injection molding nozzle section according to this embodiment. This nozzle part 24 is
It is molded into a cap shape and is attached to the tip of the valve body housing. 25 and 26 are branch holes, and 27 is a cap portion. Since the nozzle portion 24 is molded by injection molding, the cap portion 27 can be easily formed with high processing accuracy.

FIG. 4 is a sectional view (FIG. 4(A)) and a plan view (FIG. 4(B)) showing a modified example of the injection molding nozzle part.
It is. In this nozzle part 28, two branch holes 29, 3
A pair of notches 31 are provided to indicate the direction 0 and to facilitate alignment during installation. Since this nozzle portion 28 is also molded by injection molding, the notch 31 can be formed with high processing accuracy.

FIG. 5 is a longitudinal sectional view showing the main parts of a fuel injection valve according to a second embodiment. In this second embodiment, parts having the same configuration and functions as those in the first embodiment are given the same reference numerals. In this embodiment, the through hole 33 formed at the tip of the valve body housing 32 simply functions as a fuel discharge port, and the valve body housing 32 and the nozzle part 1
A through hole 35 in the plate 34 sandwiched between the fuel and the fuel cell 7 functions as a fuel metering orifice. Since this plate 34 and its through hole 35 are formed by continuous precision machining such as precision press punching, a constant fuel metering orifice without variation can be obtained.

When the fuel metering orifice 35 is constituted by the through hole 35 of the plate 34, the dotted line 36
As shown in FIG. 2, fuel may leak out of the valve from the discharge hole 33 of the valve body housing 32 through the gap between the valve body housing 32 and the plate 34, resulting in so-called bottling. To solve this problem, the surface of the nozzle portion 17 facing the tip surface of the valve body housing 32 is
As shown in FIG. 3, by providing the radial grooves 40 and 41, the fuel flows from the outer peripheral edge of the plate 34 to the nozzle portion 18,
The waste is collected at the entrance of No. 19, and it is possible to prevent the waste from falling.

[0013]

[Effects of the Invention] By having the above-described configuration, the present invention achieves the following effects. According to the fuel injection valve of claim 1, since the nozzle portion having a plurality of branch holes for branching fuel passing through the fuel metering orifice in a plurality of directions is formed by injection molding, the processing accuracy of the branch holes is high. In particular, since the wedge-shaped central wall portion between the branch holes that defines the direction of fuel branching is formed at a highly accurate angle, it is possible to perform uniform fuel distribution to each intake valve. Therefore, the double intake engine can function stably. According to the fuel injection valve of claim 2,
The through holes in the plate, which are formed by continuous precision machining such as precision press punching, function as fuel metering orifices.
The desired full-open flow rate without variation can be obtained. This allows the double intake engine to function stably. According to the fuel injection valve of claim 3, in the fuel injection valve of claim 2, by forming a groove for guiding fuel leaking from the outer periphery of the plate to the branch hole, the plate and the valve housing can be separated. Even if fuel leaks from the gap, the leaked fuel is guided to the branch hole through the groove in the nozzle part, so it is possible to prevent dripping.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing the configuration of essential parts of a fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a partially sectional perspective view showing an example of processing for molding the nozzle portion of FIG. 1 by injection molding.

FIG. 3 is a diagram showing the configuration of a modified example of the nozzle section according to the embodiment.

FIG. 4 is a diagram showing the configuration of another modification of the nozzle section according to the embodiment.

FIG. 5 is a longitudinal cross-sectional view showing the configuration of essential parts of a fuel injection valve according to a second embodiment.

FIG. 6 is a diagram showing an example of the configuration of a nozzle section for preventing droplets in the second embodiment.

FIG. 7 is a diagram illustrating another configuration example of the nozzle section for preventing droplets in the second embodiment.

[Explanation of symbols]

10 Valve body housing 11 Fuel metering orifice, 12 Valve seat 17 Nozzle part 18 Branch hole 19 Branch hole 20 Central wall 24 Nozzle part 25 Branch hole 26 Branch hole 29 Branch hole 30 Branch hole 34 Plate 35 Fuel metering orifice 40 groove 41 Groove

Claims (3)

[Claims] Claim 1: In a fuel injection valve configured to inject fuel in multiple directions, a nozzle portion having a plurality of branch holes for branching fuel passing through a fuel metering orifice in a plurality of directions is molded by injection molding. A fuel injection valve characterized by: 2. A fuel injection valve in which a nozzle portion having a plurality of branch holes for branching fuel passing through a fuel metering orifice in a plurality of directions is attached to a tip of a valve body housing, wherein a through hole is used as the fuel metering orifice. A fuel injection valve characterized in that a plate member having a perforation is disposed between the nozzle portion and the valve body housing. 3. A groove according to claim 2, wherein a groove is formed on a surface of the nozzle portion facing the plate for guiding fuel from an outer peripheral edge of the plate to the branch hole. fuel injection valve.