JPH09137764A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce flow resistance and improve a fuel injection rate and through-out force by forming a projected curve part whose both end parts are brought in contact with a valve seat and a suck part on the cross part of the seat part formed in a taper shape and the suck part subsequently to the seat part. SOLUTION: A cross part 14 of a seat part 11 in a fuel injection valve and the inner surface of a suck part 12 is formed, and also a projected curve part 15 is formed by cutting the vicinity thereof. The upper and lower end parts of the projected curve part 15 is brought in contact with the inner surface of the seat part 11 and the suck part 12, and it is successively to them smoothly. A chamfer 16 formed in a cross sectional circular arc shape is formed on the opening part of an injection port 13 in the inner surface of the suck part 12. Flow resistance of fuel is thus reduced sharply, and the flow rate of fuel in relation to the lift rate of a valve element 2 is improved. Since the inner capacity of the suck part 12 is reduced, it is possible to prevent after-dripping of fuel.

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 sack type fuel injection valve.

[0002]

2. Description of the Related Art A conventional sack type fuel injection valve is shown in FIG.
Alternatively, there is one shown in FIG. The fuel injection valve shown in FIG. 2 comprises a valve body 1 and a valve body 2, and the valve body 1
Inside the seat, there is a valve seat 11 having a tapered hole shape, and this valve seat 1
A sack portion 12 following 1 and an injection hole 13 opening to the inner surface of the sack portion 12 are formed. On the other hand, valve body 2
Is slidably provided on the valve body 1 (a sliding portion is not shown), and a valve portion 21 for seating on the valve seat 11 is provided at a lower end portion thereof.
Are formed. The valve portion 21 is positioned such that the lower end portion thereof does not reach the upper end portion of the sack portion 12 when seated on the valve seat 11. On the other hand, in the fuel injection valve shown in FIG. 3, the valve portion 21 is made longer than that shown in FIG. Other configurations are the same as those shown in FIG.

[0003]

In the conventional fuel injection valve shown in FIG. 2, the intersection 14 between the valve seat 11 and the inner surface of the sack portion 12 forms a ridge, and the intersection 14 bends both surfaces. The fuel is formed by the valve seat 11 and the valve portion 21.
When flowing into the sack portion 12 through the space between and, the intersection 14 receives a large flow resistance. As a result, there has been a problem that the fuel injection amount is reduced or the fuel penetration force is reduced. On the other hand, in the fuel injection valve shown in FIG. 3, there is an advantage that the volume of the sack portion 12 can be reduced by the amount that the valve portion 21 is extended to the inside of the sack portion 12, and the problem of fuel sagging can be reduced. On the other hand, since the valve portion 21 faces the intersecting portion 14 even when the valve body 2 is lifted, there is a problem that the flow resistance at the intersecting portion 14 is further increased and the above problem is further promoted. It was

[0004]

The present invention has been made to solve the above problems. The invention according to claim 1 has a valve seat having a tapered hole inside, and a sack continuing to the valve seat. And a valve body formed in an injection hole that opens to the inner surface of the sack portion, and a valve body that is slidably provided inside the valve body and that has a valve portion at the tip end that seats on the valve seat is formed. In the fuel injection valve having the above-mentioned feature, a convex curved surface portion whose both ends are respectively in contact with the valve seat and the sack portion is formed at the intersection of the valve seat and the sack portion. In this case, it is desirable that the tip portion of the valve portion is projected into the sack portion.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG. In the fuel injection valve shown in FIG. 1, the intersection 14 between the valve seat 11 and the inner surface of the sack portion 12 in the conventional fuel injection valve and its vicinity are removed, and a convex curved surface portion 15 is formed there. In this case, the convex curved surface portion 15 is formed in an arc shape in cross section,
Other smooth cross sections may be formed. The upper and lower ends of the convex curved surface portion 15 are in contact with the inner surfaces of the valve seat 11 and the sack portion 12, and are smoothly continuous with each other.

A chamfer 16 having an arcuate cross section is formed at the opening of the injection hole 13 on the inner surface of the sack portion 12. Both ends of the chamfer 16 are in contact with the inner surface of the sack portion 12 and the inner surface of the injection hole 13, respectively. It should be noted that, except for the above configuration, the fuel injection valve has the same configuration as that shown in FIG.

The convex curved surface portion 15 and the chamfer 16 are
It is processed as follows. That is, the elastic and viscous material mixed with abrasive grains is loaded from the upper end opening of the valve body, and pressure is applied to the valve body 11, the sack portion 12, and the injection hole 1.
It is made to flow outside through 3. Then, at the intersection of the intersection 14 and the inner surface of the fuel injection hole 13 and the inner surface of the sack portion 12, the resistance to the elastic and viscous material is large, so that the abrasive is scraped off by the abrasive grains mixed in the elastic and viscous material. As a result, the convex curved surface portion 15 and the chamfer 16 are formed.

In the fuel injection valve having the above structure, the valve seat 1
1 and the inner surface of the sack portion 12 are formed with a convex curved surface portion 15 that is smoothly continuous with them, so that the conventional crossing portion 1
As compared with the fuel injection valve having No. 4, the flow resistance to the fuel can be significantly reduced. Therefore, as shown in FIG. 4, as compared with the conventional fuel injection valve, the flow rate of the fuel with respect to the lift amount of the valve body 2 can be improved, and thus the fuel injection amount and the penetration force can be improved. . Further, since the convex curved surface portion 15 is formed by scraping off the intersection portion 14, it is possible to increase the flow area between the convex curved surface portion 15 and the valve portion 21 by the amount of scraping off. Therefore, even if the valve portion 21 is lengthened so as to extend into the sack portion 12 when seated, the fuel injection amount and the penetrating force are not reduced. Moreover, the valve section 2
By extending 1 into the sack portion 12, the internal volume of the sack portion 12 can be reduced, which can prevent post sag of the fuel.

[0009]

As described above, according to the invention of claim 1, the flow resistance to the fuel at the intersection of the valve seat and the sack portion can be reduced, whereby the fuel injection amount and the penetration force can be reduced. Can be improved. Further, according to the invention of claim 2, it is possible to prevent the fuel from sagging and reduce the flow resistance of the fuel at the same time.

[Brief description of the drawings]

1 is a view showing a main part of an embodiment of the present invention, which is a sectional view showing a state in which a valve body is seated in FIG.
(B) is a sectional view showing the valve body in a lifted state.

FIG. 2 is a sectional view similar to FIG. 1, showing an example of a conventional fuel injection valve.

FIG. 3 is a diagram showing another example of a conventional fuel injection valve,
3A and 3B are sectional views similar to FIGS. 1A and 1B, respectively.

FIG. 4 is a diagram showing a relationship between a lift amount and a fuel flow rate in each fuel injection valve of the related art and the present invention.

[Explanation of symbols]

 1 Valve body 2 Valve body 11 Valve seat 12 Suck part 13 Injection hole 15 Convex curved surface part 21 Valve part

Claims (2)

[Claims] 1. A valve main body formed inside a valve seat having a tapered hole shape, a sack portion continuing to the valve seat and an injection hole opening to the inner surface of the sack portion, and slidable inside the valve main body. A fuel injection valve provided with a valve body having a valve portion for seating on the valve seat formed at a front end thereof, the both ends of the valve seat and the intersection of the valve seat and the sack portion being A fuel injection valve characterized in that a convex curved surface portion is formed in contact with each sack portion. 2. The fuel injection valve according to claim 1, wherein a tip portion of the valve portion is projected into the sack portion.