JPH0388961A - Manufacture of fuel injecting nozzle - Google Patents

Abstract

PURPOSE:To provide a fuel injection nozzle which achieves fine atomization by boring a jet at the tip of a nozzle body, inserting a press shaft in the body, compresses the tip, and by deforming the section of jet flat. CONSTITUTION:After forming a basic jet 13, a press shaft 14 is inserted in a cylindrical part 11, and the nozzle body 1 is raised up so that its crest 15 at the tip 2 is in contact with and supported by a press table 16. The press shaft 14 is depressed along the axis A with a specified pressure so as to shrink the distance H from the end face of press shaft 14 to the press table 16 by a specified amount H, and the tip 2 is crushed in the direction plumb. With this press, the basic jet 13 is deformed into a flat jet 18 having approx. a flat section. A fuel injection nozzle fabricated in this fashion generates atomization C into a combustion chamber 19 in the injection range theta2 enlarged from the range theta1 due to conventional genuine circular jet (theta1<theta2), and thus fine atomization is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a fuel injection nozzle having a nozzle at its tip.

[Prior Art] Generally, a diesel engine is equipped with a fuel injection nozzle for appropriately injecting fuel into a combustion chamber depending on operating conditions.

As shown in FIG. 5, conventional fuel injection nozzles of this type:
The tip part 2 of the nozzle book #l is formed into a hemispherical shape, etc., and a valve seat part 4 on which the needle valve 3 is seated is provided inside the tip part 2. is a perfect circular spout 5
, 6 are formed. Then, by raising and lowering the needle valve 3 along the axis A, fuel is supplied to the fuel supply FI? The fuel is guided from the I7 through the pressure chamber 8 and the valve seat 4 to the injection ports 5 and 6, and is injected at a predetermined timing.

[Problem H that the invention seeks to solve] By the way, in recent years, legal regulations regarding smoke and particulates have become stricter in measures against exhaust gas from automobiles, etc., making it difficult for diesel engines to survive in the future. This is the most important issue in the future.

In order to solve this problem, the fuel injection nozzle uses high-pressure injection to atomize the spray.
Efforts are being made to improve mixing with intake air and improve fuel efficiency.

For this reason, it is necessary to increase the number of nozzles or to increase the diameter d of the nozzle 5°6.
Although attempts have been made to reduce the diameter d, this diameter d is naturally limited by processing limits, and it is difficult to achieve an ideal nozzle diameter.

Therefore, it is conceivable to change the cross-sectional shape of the nozzle ports 5 and 6, which are conventionally perfect circles, to atomize the spray. As a technique for this, for example, as disclosed in ``Fuel Injector J for Internal Combustion Engines (Japanese Unexamined Patent Publication No. 58-82574), it has been proposed to reduce the diameter of the nozzle in the axial direction to make it elliptical. ing.

According to this configuration, the spray is diffused in the circumferential direction within the combustion chamber, and 0! The above-mentioned problem of atomization of fog will be solved to some extent.

However, it has been difficult to manufacture this configuration. In other words, the nozzle is usually formed by forming the nozzle body from a metal such as cast iron, drilling a hole at a predetermined position at the tip, and precision-machining it into a perfect circle. , it is extremely difficult to form it into a flat shape such as an ellipse.

It is also conceivable to make the tip or the vicinity of the nozzle made of ceramics and to utilize its good processing characteristics to mold the nozzle into a desired shape. However, in this case, new problems arise, such as poor bondability with the nozzle body, which is made of metal, or a decrease in durability due to a difference in coefficient of thermal expansion.

In view of the above circumstances, the present invention was devised to provide a manufacturing method for realizing a fuel injection nozzle having a flat nozzle that achieves atomization of fuel spray.

[Means and effects for solving the problem] The present invention involves drilling a nozzle in the tip of a nozzle body formed of metal in a direction intersecting the axis of the nozzle body, and then inserting a press shaft into the body. The tip is compressed in the axial direction to flatten the cross-sectional shape of the nozzle.

By the above method, without using ceramics,
A fuel injection nozzle with a flat nozzle can be obtained.

[Example code] Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 and 2 show an embodiment of the method for manufacturing a fuel injection nozzle according to the present invention, and among the configurations of the fuel injection nozzle to be manufactured, the same reference numerals are used for the same components as in the conventional one. , and the explanation thereof will be omitted.

First, the nozzle body 1 is metal-cast by a known manufacturing method to form a hemispherical tip portion 2, a valve seat portion 4, a fuel supply passage 7, a pressure chamber 8, and a cylindrical portion 11 that guides a needle valve (not shown).
etc. are each molded into a predetermined shape.

Then, a drill hole is drilled with the drill 12 from the outside of the tip 2 in an oblique direction intersecting the axis A, that is, in a direction that appropriately faces the combustion chamber (not shown) from the inside of the tip 2. This hole is then precisely machined to form a basic nozzle 13 with a perfect circular cross section (diameter d).

After forming this basic nozzle 13, as shown in FIG. stand up as if

This press shaft #14 has a maximum diameter smaller than that of the needle valve, and its tip is reduced in diameter into a truncated conical shape, and its conical portion 1
7 is formed so as to be in surface contact with the valve seat portion 4.

Then, the press shaft 14 is pushed down along the axis A with a predetermined pressure, and the press stand 16 is pushed down from the end surface of the press shaft 14.
By reducing the distance H by a predetermined amount ΔH, the tip portion 2 is crushed in the vertical direction.

With this press, as shown in FIG. 3, the basic nozzle 13
is an approximately oval (elliptical) flat nozzle 1 that is shortened in the axial direction.
It is transformed into 8. That is, the diameter d1 of the flat nozzle 18 in the axial direction A is smaller than the original diameter d, and the diameter d2 in the circumferential direction B is larger than the original diameter d (d 1 <
d<d2) is formed.

As shown in FIG. 4, the fuel injection nozzle manufactured in this manner has a spray C that is sprayed into one combustion chamber during fuel injection, which is larger than the injection range θ1 produced by the conventional perfect circular nozzle. The injection range θ2 becomes (θ, θ2), and atomization of the spray is achieved.

That is, mixing with intake air within the combustion chamber 19 is promoted,
It is possible to reduce the generation of smoke and particulates. Especially when using a high injection pressure nozzle,
Spray spread is important because very small swirl tends to be good.

In this way, after drilling a perfectly circular basic nozzle 13 in the tip 2 of the nozzle body 1, the press shaft 14 is inserted into the cylindrical part 11, the tip 2 is pressed, the basic nozzle 13 is deformed, and the Shinpei Since the spray 018 is shaped, a metal fuel injection nozzle that aims to atomize the spray can be reliably and easily realized.

Therefore, in order to process the nozzle into a flat shape, there is no need to partially make the tip and the vicinity of the nozzle made of ceramic, and problems with bondability and durability associated with ceramicization do not occur.

Further, the degree of flatness of the nozzle can be determined by adjusting the press pressure, that is, the degree to which the tip is crushed (ΔH), which is extremely practical in terms of manufacturing control.

[Effects of the Invention] In short, the present invention provides the following excellent effects.

After drilling a nozzle at the tip of the nozzle body, a press shaft is inserted into the body to compress the tip and flatten the cross-sectional shape of the nozzle, thereby achieving atomization of the spray. A fuel injection nozzle can be realized.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of a nozzle body showing an embodiment of the method for manufacturing a fuel injection nozzle according to the present invention, Fig. 2 is a surface survey showing the next step, and Fig. 3 is Fig. 2. Inside ■ arrow view,
FIG. 4 is a plan view of a combustion chamber for explaining the operation of the manufactured fuel injection nozzle, and FIG. 5 is a side sectional view of the fuel injection nozzle manufactured by a conventional manufacturing method. In the figure, 1 is the nozzle body, 2 is the tip, 13° and 18 are the basic nozzle and flat nozzle, 14 is the press shaft, and A is the axis. 0) Taste

Claims (1)

[Claims] 1. After drilling a nozzle in the tip of a nozzle body formed of metal in a direction crossing the axis thereof, inserting a press shaft into the body and compressing the tip in the direction of the axis, A method of manufacturing a fuel injection nozzle, characterized in that the cross-sectional shape of the injection port is deformed into a flat shape.