JPH08232809A - Hole type fuel injection nozzle - Google Patents

Abstract

PURPOSE: To provide a hole type fuel injection nozzle for improving atomization, wherein, working is facilitated, and application is not only enabled on a jerk type pump and the system of an automatic valve, but also on an electrically controlled common rail injection device. CONSTITUTION: In a hole type fuel injection nozzle 100, injection port groups 1 to 5 made of at least three injection ports or more are formed, respective diameters of the injection ports 1, 5 positioned on most outer side are formed smaller than those of injection ports 2, 3, 4 positioned on an inner side therefrom, sprays of fuel supplied from respective injection ports 1 to 5 are fed in nearly same direction without crossing directly, and sprays 10 to 50 of fuel supplied from the injection ports which are positioned near to each other are interfered with each other. The injection ports are arranged in such a constitution so as to promote spray of fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Hall-type fuel injection nozzle used in a diesel internal combustion engine.

[0002]

2. Description of the Related Art As a method for improving the emission of a direct injection type diesel engine, a combination of a small diameter injection port and a high injection pressure of a fuel injection nozzle, a spray collision on a piston top surface such as a reentrant combustion chamber, a swirl matching fuel Studies are being conducted to promote atomization.

However, as shown in FIG. 5, with respect to the hole type fuel injection nozzle 100, a liquid rich region remains in the spray, which causes smoke in the exhaust gas. Therefore, as disclosed in Japanese Unexamined Patent Publication No. 64-45960, with regard to the Hall-type fuel injection nozzle, the fuel sprays from the two nozzles are crossed so that the spray sprays into the combustion chamber at low load and high load. There are also attempts to change people.

[0004]

Problems to be Solved by the Invention JP-A-64-4596
In order to arrange two nozzles in a plane that includes the axis of the needle of the nozzle and cross them well like 0, it is necessary to perform processing with extremely high precision, and an abnormal direction inside the combustion chamber such as the wall surface or head cylinder. Two sprays will scatter, which will lead to worse emission and engine damage.

Further, in this known example, a system using a so-called jerk pump and an automatic valve in which the injection amount and the pressure change substantially linearly, and a needle lift at a low load and a high load if high-precision hole drilling is possible. Since the amount changes and there is a difference in the injection amount from each of the upper and lower injection ports, it is possible to change the way of spraying. However, in a so-called electronically controlled common rail injection device such as Japanese Patent Laid-Open No. 5-332220, the injection pressure is arbitrary and the needle lift is always constant, so the effect of changing the spray direction cannot be expected.

Further, by using the common rail injection device, the fuel injection pressure is increased to 120 MPa, and the fuel injection pressure is reduced to 0.
Even if the nozzle nozzle size is reduced to about 15 mm, the liquid-rich region in the center of the spray decreases as shown in FIG. 5 as a conventional example, but it does not disappear, so this region causes smoke. Will be. Therefore, the present invention provides a Hall-type fuel injection nozzle with improved atomization, which is easy to process and can be applied not only to a jerk pump and an automatic valve system but also to an electronically controlled common rail injection device. This is the problem to be solved by the invention.

[0007]

In order to achieve the above-mentioned object, the present invention forms a nozzle group including at least three nozzles in a hole-type fuel injection nozzle, and the outermost nozzles are more than that. The diameter of the fuel spray is smaller than that of the inner nozzles, and the fuel sprays from the respective nozzles do not directly intersect each other but go in substantially the same direction, and the fuel sprays from the adjacent nozzles interfere with each other. The technical means of accelerating atomization of the fuel by arranging the nozzles in the above is adopted.

[0008]

[Operation and effect] The most concentrated cause of smoke is the liquid rich region remaining in the center of the spray injected from a single injection port. In the present invention, the outermost nozzle has a small diameter to reduce the liquid rich region as much as possible. Further, atomization of the spray from the inner nozzle is promoted by the interference effect of the spray from the outer nozzle and the spray from the inner nozzle. Since the sprays on the inner side interfere with the sprays from both sides, the effect of promoting atomization is greater than that on the outermost nozzles, and therefore sufficient atomization of fuel is possible even if the diameter of the nozzles is large.

With the structure of the present invention, it is possible to suppress the generation of the liquid rich region in the spray, which is the largest cause of the smoke generation, the smoke generation is prevented, and the emission is greatly improved.

[0010]

1 is a perspective view of a Hall type fuel injection nozzle according to a first embodiment of the present invention. In the first embodiment of the present invention, three or more nozzles 1 to 5 are slidable on the nozzle 100 as shown in FIG. 1 corresponding to the nozzles of the conventionally known multiple nozzles 100 shown in FIG. The injection port groups 1 to 5 are provided so as to be close to each other in a direction substantially perpendicular to the axial direction of the fitted needle, and the size of the outermost injection port is smaller than the size of the injection port inside thereof.

Therefore, as shown in FIG. 2, atomization of the sprays from the nozzles 2 to 4 located inside the nozzle groups 1 to 5 is promoted by the mutual interference effect of the sprays from the adjacent nozzles on both sides. . Moreover, since the sprays from the outermost nozzles 1 and 5 are smaller than the nozzles inside the nozzles, there is originally a small amount of liquid rich region, and the nozzles inside the nozzles are smaller than when there is a single nozzle. The atomization of the fuel is promoted by the interference effect of the spray.

Therefore, in order to obtain a spray having the same degree of atomization, even if the injection pressure is not set to be higher than that when there is a single injection port, it is uniform over the entire area where there is no liquid concentrated region as in the past. It is possible to suppress the generation of smoke by forming a spray that is distributed in the area. FIG. 2 is a view of the fuel sprays 10 to 50 injected from the injection port groups 1 to 5 in FIG. 1 as seen from the direction of arrow A in FIG.

In the present invention, the fuel injected from the nozzles is not arranged so as to directly intersect each other, but the respective nozzles 1 are directed toward the intended direction in the combustion chamber as shown in FIG.
Since the fuel injected from the nozzles 5 to 5 may be arranged in a substantially aimed direction so as to interfere with each other, the direct injection port 1
It is not necessary to perform high-precision machining accuracy control such as machining the nozzles 1 to 5 so that the fuel injected from 5 to 5 intersects.

The size of the nozzles may be distributed so as to be equal to the flow passage area of a single nozzle, but in the first embodiment of FIG. 1, the outermost nozzles 1 and 5 are liquid. In order to minimize the concentration region, the diameter of the injection hole is set to the minimum of the machining limit of the hole diameter, and the remaining injection holes 2, 3 and 4 are excluded from the flow path area of the injection holes 1 and 5, and the flow path of a single injection hole is set. It suffices to divide it into equal parts so as to have the same area.

FIG. 3 shows a perspective view of the second embodiment of the present invention. The spout groups 1a to 5a are formed around the main spout 1a by the spouts 2a to 2a.
5a is arranged without the axes of the respective nozzles 1a to 5a directly intersecting with each other, and the nozzles 2a to 5a are arranged so as to interfere with the main nozzle 1a. FIG. 4 shows nozzles 1a, 2a, 4
It is the figure which looked at the mode that fuel spray 10a, 20a, 40a injected from a mutually interferes from the direction of arrow A in Drawing 3.

The operation and effect are similar to those of the first embodiment. In the embodiment shown in FIG. 1 and FIG. 3, the example in which the nozzle group is 5 nozzles is shown. However, the effect of the present invention can be obtained when the number of the nozzles is 3 or more. But it doesn't matter.

[Brief description of drawings]

FIG. 1 is a perspective view of a Hall-type fuel injection nozzle according to a first embodiment of the present invention.

FIG. 2 is a fuel spray 1 injected from the injection port groups 1 to 5 in FIG.
It is the figure which looked at 0-50 from the arrow A direction of FIG.

FIG. 3 is a perspective view of a second embodiment of the present invention.

FIG. 4 is a view showing how fuel sprays 10a, 20a, 40a injected from injection ports 1a, 2a, 4a interfere with each other, as seen from the direction of arrow A in FIG.

FIG. 5 is a diagram showing a spraying state of a Hall-type fuel injection nozzle in a conventional direct injection diesel engine.

[Explanation of symbols]

1, 2, 3, 4, 5, 1a, 2a, 3a, 4a, 5a
Nozzle group 1, 5, 2a, 3a, 4a, 5a Outermost nozzle 2, 3, 4, 1a Inner nozzle 10, 20, 30, 40, 50, 10a, 20a, 40
a spray 100 nozzle

Claims (1)

[Claims] 1. A Hall-type fuel injection nozzle, wherein an injection hole group consisting of at least three injection holes is formed, and the outermost injection holes have a smaller diameter than the inner injection holes, and The atomization of the fuel is promoted by arranging the fuel sprays from the nozzles so that the fuel sprays from the adjacent nozzles interfere with each other in almost the same direction without intersecting directly with each other. A hall-type fuel injection nozzle characterized by: