JPH0218424B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fuel injection valve for a fuel injection carburetor installed in an internal combustion engine for an automobile.

Prior Art A fuel injection valve device is provided in a carburetor of an internal combustion engine for an automobile due to various advantages. Conventional fuel injection valves have a structure such as that proposed in Utility Model Application No. 58-51055, in which a bottom feed type fuel injection valve is used, as shown in Figures 1 to 3. The valve 1 is mounted on the throttle body 2 of the carburetor. The low-pressure fuel fed by the fuel feed pump passes through a filter 6 from a fuel passage 5 sealed by O-rings 3 and 4 to an internal hollow part 8 of a valve body 7 of the fuel injection valve 1.
The fuel injection hole 1 at the lower end of the valve passes between the valve 9 and the seat surface 10 on which the valve 9 is attached/detached.
It is injected from 1. The valve 9 has a pintle portion 12 at its lower end, and when the pintle portion 12 is inserted through the fuel injection hole 11, the injection mode and the like are controlled.

In the fuel injection valve 1 having a conventional configuration, the pintle portion 12 normally projects downward from the lower end of the valve body 7 when the valve 9 is seated on the seat surface 10. Even if the lower end of the outer wall of the valve body 7 The lower end of the pintle part 12 was configured to be at the same position as the lower end of the valve body 7 even though it protruded downward so as to surround the periphery of the pintle part 12. However, in a fuel injector having such a structure, the pintle part 12 is exposed outside the valve body 7, or the tip of the pintle part 12 reaches the bottom surface of the valve body 7 and hits an object, so when one fuel injector is assembled, There was a risk that the pintle portion 12 would be damaged by hitting an object, and careful assembly work was required.

In addition, since the outer circumferential surface of the lower end of the valve body 7 is chamfered in three stages, the wall thickness is thin and rigidity is low.
There was also a problem in that the operating noise was loud during idling because the operating noise was amplified by being transmitted to the throttle body 2 via the engine.

Purpose of the Invention In order to solve the above-mentioned problems, the present invention improves the structural relationship between the pintle part and the valve body to prevent the pintle part from being damaged when assembling the fuel injection valve. The purpose is to increase the rigidity of the lower end of the body and reduce the amplification of the operating noise of the fuel injection valve, thereby suppressing the operating noise during idling.

Structure of the Invention In order to achieve this object, in the fuel injection valve of the present invention, a valve is provided in an internal hollow part of a valve body so as to be attachable to and detachable from a seat surface, and a fuel injection valve is provided at a lower end of the valve body. A pintle portion formed at the lower end of the valve is inserted into the injection hole. The outer wall of the valve body extends around the pintle part, so that even when the valve is seated on the seat surface, the pintle part is surrounded by the outer wall of the valve body and the lower end of the pintle is located above the lower end of the valve body. It is made to be. Further, the outer circumferential surface of the lower end of the valve body is chamfered with a radius, and the structure is determined such that a line connecting the center of the radius and the center of seating of the valve on the seat surface is orthogonal to the seat surface.

Effect of the Invention In the fuel injection valve for an internal combustion engine configured as described above, the pintle portion is surrounded by the lower end of the valve body and is not exposed outside the valve body. Therefore, the pintle part will not be damaged by hitting an object when assembling the fuel injector. Furthermore, since the lower end outer circumferential surface of the valve body is rounded, the wall thickness of the lower end outer wall of the valve body is increased compared to a case where the outer circumferential surface of the lower end of the valve body is chamfered in a straight line such as three-stage chamfering, and the rigidity is increased. In addition, since the structure is such that the line connecting the center of R and the seating center of the valve is perpendicular to the seat surface, the valve is placed on the line connecting the center of R and the seating center of the valve, where the greatest valve load is applied. The outer wall of the body can be made thickest, and the rigidity against the valve load can be most effectively increased. This increase in rigidity suppresses the increase in operating noise when the fuel injection valve operates.

Effects of the Invention Therefore, when using the fuel injection valve for an internal combustion engine of the present invention, the above-mentioned improvement of the structure of the lower end of the valve body makes it possible to prevent damage to the pintle portion when assembling the fuel injector, and to prevent damage to the pintle portion at the lower end of the valve body. By increasing the rigidity, it is possible to reduce the operating noise of the fuel injection valve.

Embodiments Below, preferred embodiments of the fuel injection valve for an internal combustion engine of the present invention will be described with reference to the drawings.

4 to 6 show bottom feed type fuel injection valves according to embodiments of the present invention.
In the figure, reference numeral 1 denotes a fuel injection valve, which is mounted on the throttle body 2 of the carburetor as in the conventional figure 1. O-rings 3 and 4 are interposed between the fuel injection valve 1 and the fuel injection valve mounting hole of the throttle body 2, and cut off the fuel injection passage 5 to the fuel injection valve 1 from the outside and from the intake passage. The fuel injection valve 1 has an internal hollow part 8 therein, and the fuel passage 5 and the internal hollow part 8 are communicated with each other via a filter 6 attached to the fuel injection valve 1. A valve 9 is inserted into the internal hollow part 8 of the fuel injection valve 1 so as to be able to move up and down, and is moved up and down by a drive section 14 that is operated by a current supplied from a power connector 13 . The lower surface of the internal hollow portion 8 is a tapered seat surface 10, and the valve 9 is attached to and detached from the seat surface 10 to control fuel injection. A fuel injection hole 11 is formed in the center of the lower end of the valve body 7 and extends through the valve body 7 in the vertical direction. Further, a pintle portion 12 is provided at the lower end of the valve 9 to protrude downward, and the pintle portion 12 is inserted into the fuel injection hole 11 when the valve 9 is seated on the seat surface 10. The structure up to this point is similar to the conventional fuel injection valve shown in FIGS. 1 to 3.

However, in the embodiment of the present invention, the lower end projecting portion 15 radially surrounds the pintle portion 12 that passes through the fuel injection hole 11 and projects downward when the valve 9 is seated on the seat surface 10. I'm reading. Further, the lower end projecting portion 15 extends downward so that its lower end is located below the lower end of the pintle portion 12 when it is at the lowest position.

The outer circumferential surface of the lower end of the valve body 7 is chamfered in an R direction instead of being chamfered in three stages in the past. 16 indicates this rounded chamfer. Also, an imaginary line 1 connecting the center 17 of the R chamfer and the seating center 18 of the valve 9 on the seat surface 10
The relative position of the R-chamfered portion 16 and the seating center 18 is determined so as to be perpendicular to the seat surface 10 .

Next, the operation of the embodiment apparatus configured as described above will be explained.

First, fuel is fed at low pressure to the fuel injection valve 1 through the fuel passage 5 by the fuel feed pump. As the fuel passes through the filter 6, foreign substances are finally removed, and the fuel enters the internal hollow part of the fuel injection valve 1, passes between the valve 9 and the seat surface 10, and enters the gap between the fuel injection hole 11 and the pintle part 12. It is injected into the intake passage 12 of the carburetor in an umbrella shape. O-rings 3 and 4 prevent fuel from leaking. fuel injection valve 1
When the throttle body 2 operates, vibrations are transmitted to the throttle body 2 via the O-rings 3 and 4, and the operating noise tends to be amplified.

However, in the device of this embodiment, since the outer wall at the lower end of the valve body 7 extends downward and the chamfering of the lower end projecting portion 15 is rounded, the wall thickness of the outer wall at the lower end of the valve body 7 is increased. has been significantly increased compared to before. Moreover, the surface on which the largest load from the valve 9 acts, that is, the surface including the line 19 connecting the center 17 of the R-chamfered portion 16 and the seating center 18 of the seat surface 10, passes exactly through the seating center 18 and reaches the seat surface 10. Therefore, for the maximum load from the valve 9 acting in the direction perpendicular to the seat surface 10 from the seating center 18,
The lower end outer wall of the valve body 7 has the greatest thickness and has the greatest rigidity against the valve load. This increase in rigidity reduces vibrations of the fuel injector 1, especially large vibrations at idle,
To suppress the increase in operating noise of a throttle body due to vibrations transmitted from a fuel injection valve 1 via O-rings 3 and 4.

FIG. 7 shows the effect of reducing operating noise. In the figure, a dashed-dotted line A indicates the sound pressure level when the conventional fuel injection valve shown in FIGS. Indicates the sound pressure level when the injection valve is activated. As is clear from the figure, the frequency range is 1.0KHz to 16K.
It has good noise reduction effect at Hz.

Further, the pintle portion 12 does not protrude downward from the lower end of the valve body 7 because the outer wall of the lower end of the valve body 7 is extended downward and the periphery thereof is wrapped. Therefore, when the fuel injection valve 1 is assembled to the throttle body, the pintle portion 12
There is no risk of damage due to contact with objects, and the installation is highly reliable.

Therefore, when using the fuel injection valve for the internal combustion engine of the present invention shown in the embodiment device as described above,
The rigidity of the lower end of the valve body is increased, which not only reduces operating noise when the fuel injection valve operates, but also prevents damage to the pintle portion.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a conventional fuel injection valve mounted on a throttle body, Fig. 2 is a front view of the conventional fuel injection valve, and Fig. 3 is a sectional view of the lower end of the fuel injection valve of Fig. 2. FIG. 4 is a front view of a fuel injection valve for an internal combustion engine according to an embodiment of the present invention, FIG. 5 is a sectional view of the lower end of the fuel injection valve in FIG. 4, and FIG. FIG. 7 is a diagram showing the sound pressure level of a conventional fuel injection valve and a fuel injection valve of the present invention. DESCRIPTION OF SYMBOLS 1... Fuel injection valve, 3, 4... O-ring, 5... Fuel passage, 7... Valve body, 8... Internal hollow part, 9...
Valve, 10... Seat surface, 11... Fuel injection hole, 1
2...Pintle portion, 15...Lower end overhang, 16...R chamfered portion, 17...R center, 18...Setting center.

Claims (1)

[Claims] 1 Fuel for a bottom-feed type internal combustion engine in which a valve is provided in the internal hollow part of the valve body so that it can be attached to and removed from the seat surface, and a pintle part formed at the lower end of the valve is inserted into a fuel injection hole formed at the lower end of the valve body. In an injection valve, the outer wall of the valve body is extended around the pintle part so that even when the valve is seated on the seat surface, the pintle part is surrounded by the outer wall of the valve body and the lower end of the pintle is positioned above the lower end of the valve body. In addition, an internal combustion engine characterized in that the outer circumferential surface of the lower end of the valve body is chamfered with a radius such that a line connecting the center of the radius and the center of seating of the valve on the seat surface is perpendicular to the seat surface. fuel injection valve.