JPS591104Y2 - Diesel engine fuel injection valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection valve for a diesel engine, and more particularly to a fuel injection valve incorporating means for attenuating reflected waves during fuel injection.

When an automatic valve is used for the injection valve, a pressure wave is generated during fuel injection, and a reflected wave is also generated, and the automatic valve type injection valve opens at a time other than the specified timing due to the influence of this reflected wave, causing the fuel to flow out. It is well known that the phenomenon of inadvertent injection (so-called multiple injection) occurs.

The present invention uses a fuel filter installed inside the fuel injection valve as a means for attenuating such reflected waves. The fuel pump side is formed as a small diameter part and the nozzle side is formed as a large diameter part, a stepped part is provided at the boundary between the small diameter part and the large diameter part, and the large diameter part has a conical tip and a hollow cylindrical body. The conical part has a filter in which a small hole is formed at the tip of the conical part to form a throttle hole that communicates with the inside of the cylindrical part, and a filter body having an edge groove is stretched on the outer peripheral surface of the cylindrical part. This is a fuel injection valve for a diesel engine that is mounted toward the small diameter part so that it is pressed against the step part by the pressing force of a spring and acts as a check valve.

Next, embodiments of the present invention will be described with reference to the drawings.

In the figure, reference numeral 1 indicates a casing of a fuel injection valve, and a passage 3 having a large diameter portion 4 is bored in the casing 1 in which a filter 2 whose tip is a conical cylindrical body is housed. There is.

The large diameter part 4 is connected to the other part (small diameter part) of the passage 3 via a step part 5, and the conical part 2a of the filter 2 is attached to the step part (corner part) 5 by the pressing force of the spring 6. When pressed, the filter 2 acts as a check valve.

As the details of the filter 2 are shown in FIGS. 2 and 3,
A filter paper 9 (filter cloth) is stretched over the outer peripheral surface of the cylindrical portion 2b, and the filter paper 9 is provided with an edge groove 7.

Further, a small hole 8 forming a throttle hole communicating with the inside of the cylindrical portion 2b is bored at the tip of the conical portion 2a.

Further, near the rear end of the cylindrical portion 2b, a plurality of small holes 10 are bored through the cylindrical body from the inside to the outside.

During operation of the engine, fuel oil pumped from a fuel injection pump (not shown) flows into a passage 3 formed in the casing 1 of the fuel injection valve from the direction of arrow A in FIG.

Then, the filter 2 is pushed to the right against the pressing force of the spring 6, separating the filter 2 from the stepped portion 5 of the passage 3, and the fuel oil flows into the edge groove 7 provided in the filter paper 9. do.

Then, this fuel oil flows through the filter paper 9 in the circumferential direction from the edge groove 7, as illustrated by the arrow in FIG.
At this time, large-diameter foreign objects in the fuel oil are removed) from the adjacent edge grooves 7, flow into the filter 2 through the small holes 10, and then flow from the inside of the filter 2 through the opening 11 to the nozzle side B. and reaches a needle valve (not shown), which is then pushed open and injected into the combustion chamber.

The reflected wave generated when the needle valve of the injection valve closes flows in the opposite direction to the flow of the fuel oil described above, but at this time, the filter 2 comes into contact with the stepped portion 5 and closes the flow path. Therefore, the reflected wave will pass through the small hole 8 that forms the aperture hole.
Since the cross-sectional area of the small hole 8 is narrowed, the reflected waves are
(the small hole), it is attenuated and hardly transmitted to the fuel conduit (the pipe connecting the fuel injection pump and the fuel injection valve).

As described above, in the present invention, the reflected waves are reduced by providing a throttle in the fuel system, so that multiple injections due to reflected waves can be prevented.

In addition, this invention has this aperture installed in the fuel filter that is installed in most engines (especially in all large engines), so there is no need for any separate components, which reduces costs. In addition, since the filter is installed with the check valve in operation, there is no risk that this throttle hole will have an adverse effect during fuel supply (fuel injection).

. As described above, according to the present invention, it is possible to attenuate the reflected waves during fuel injection without adding any special parts, and since it does not affect the fuel supply in any way, engine performance is improved. can be further improved.

Since the implementation of the present invention does not result in any particular increase in cost, it is extremely easy to implement, and the present invention can be said to be highly practical.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a side sectional view, FIG. 2 is a side view of a filter, and FIG. 3 is an enlarged perspective view of a filter paper portion thereof. 1... Casing, 2... Filter, 3... Passage,
5... Step portion, 6... Spring, 7... Edge groove, 8
...Small hole of aperture hole, 9...Filter paper, 10...Small hole.

Claims (1)

[Scope of utility model registration request] The fuel oil passage in the casing of the fuel injection valve is formed with a small diameter part on the fuel pump side and a large diameter part on the nozzle side, and a stepped part is provided at the boundary between the small diameter part and the large diameter part, and in the large diameter part, The tip is conical,
The body has a hollow cylindrical shape, and a small hole is formed at the tip of the conical part to form a throttle hole that communicates with the inside of the cylindrical part, and a filter body having an edge groove is provided on the outer peripheral surface of the cylindrical part. A fuel injection valve for a diesel engine in which a filter is mounted toward a small diameter portion so that the conical portion thereof is pressed against the step portion by the pressing force of a spring and acts as a check valve.