JP2566196Y2 - Hall type fuel injection nozzle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hole-type fuel injection nozzle having a main injection hole and a sub-injection hole having different injection hole angles with respect to the axis, and being obliquely attached to the combustion chamber.
The present invention relates to a Hall-type fuel injection nozzle for equalizing the injection flow rate between a main injection hole and a sub injection hole.

[0002]

2. Description of the Related Art In general, it is impossible to mount a fuel injection nozzle vertically to a combustion chamber of a two-valve diesel engine because an intake / exhaust valve interferes with the engine. I have no choice. In this case, in order to inject the fuel b symmetrically toward the combustion chamber a, the angle formed between the nozzle axis c and the injection hole d differs depending on the injection hole position.

[0003] That is, the angle between the injection hole d ₂ (hereinafter referred to as the sub injection hole) on the side where the fuel injection nozzle e is inclined and the nozzle axis c is β, and the injection hole d ₁ on the opposite side (hereinafter referred to as the main injection hole). Called a hole)
Assuming that the angle between the nozzle axis and the nozzle axis c is α, β is larger than α and α <β. In the drawings, f is a needle valve that moves up and down in the nozzle body, and g is a seat on which the needle valve is seated.

[0004]

[Problem to be solved by the invention] In this configuration,
When the fuel injection needle valve f is lifted from the seat portion g, since the sub nozzle hole d ₂ is the bending of the fuel flow channel than the main injection hole d ₁ becomes tight, and increases the flow resistance in the main injection hole d ₁ In comparison, the injection flow rate is reduced. As a result, the distribution of "fuel / air" is not uniform in the combustion chamber "a", resulting in a decrease in output and deterioration in smoke.

[0005] As a countermeasure, the nozzle hole diameter of the secondary injection hole d ₂ larger than the main injection hole d _1, mainly techniques to make uniform the injection flow rate between the sub-nozzle holes are known. However, in this case, the spray particle size of the secondary injection hole d ₂ side having an increased nozzle hole diameter becomes larger than the spray particle diameter of the main nozzle hole d ₁ side, sufficient effect can not be obtained.

SUMMARY OF THE INVENTION An object of the present invention, which has been made in view of the above circumstances, is to provide a Hall-type fuel injection nozzle in which the injection flow rates of a main injection hole and a sub injection hole are equalized.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a seat portion is provided inside a nozzle body on which a needle valve which moves up and down is seated, and a tip portion of the nozzle body below the seat portion is provided. In a hole type fuel injection nozzle provided with a main injection hole having a small angle with the axis and a sub injection hole having a large angle, a cutout portion is formed at a lower portion of the seat portion on the side of the sub injection hole, and the seat portion and the needle valve are formed. The outlet area of the fuel passage formed between the main injection hole side and the sub injection hole side is wider than that of the main injection hole side by the notch.

[0008]

By forming a cutout in the lower portion of the seat where the needle valve is seated on the side of the sub-injection hole, the outlet area of the fuel flow path formed between the needle valve lifted during fuel injection and the seat is reduced. On the side of the sub-injection hole, it is wider than that of the main injection hole by the notch.

As a result, the angle formed with the axis is larger than the area of the fuel flow path exit on the side of the main injection hole where the angle formed with the nozzle axis is smaller and the fuel flow path is less bent. The area of the fuel passage outlet on the side of the sub injection hole becomes large.

Therefore, the change in the injection amount due to the steepness of the curve of the fuel passage is offset by the size of the exit area of the fuel passage, and the fuel from each of the main and sub injection holes is changed without changing the injection hole diameter. The injection amounts become substantially equal.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a rounded cylindrical sack portion 3 with a bottom is formed at the tip of a nozzle body 2 which accommodates a needle valve 1 so as to be movable up and down. Sack part 3
Has a main injection hole 4a having a small angle with the axis 3a.
(Angle α) and a large sub injection hole 4b (angle β).

Inside the nozzle body 2, a cone-shaped seat portion 5 on which the inverted conical needle valve 1 is seated is formed at the upper edge of the sack portion 3. That is,
A seat portion 5 on which the needle valve 1 is seated is provided inside the nozzle body 2, and a main injection hole 4 a and a sub injection hole 4 b are provided at a tip of the nozzle body 2 below the seat portion 5.

According to this configuration, when the needle valve 1 is lifted from the seat portion 5 as shown by a dashed line in the figure during fuel injection, the fuel pressurized by the fuel injection pump and supplied to the upper part of the nozzle body 2 is The fuel flows into the sack portion 3 through a fuel flow path formed between the seat portion 5 and the needle valve 1, and is injected from the main and sub injection holes 4a and 4b.

As shown in FIG. 4, such a hole-type fuel injection nozzle is attached to a cylinder head h at an angle to the sub-injection side 4b, and fuel injected from the main and sub-injection holes 4a, 4b is applied to the piston top i. The fuel is supplied symmetrically into the formed combustion chamber a.

The present embodiment is characterized in that a cutout 6 (chamfer) is formed in a lower portion 5a of the seat portion 5 on the side of the sub-injection hole 4b, and is formed between the seat portion 5 and the needle valve 1. The point that the exit area of the fuel flow path is wider on the side of the sub injection hole 4b than on the side of the main injection hole 4a. Notch 6
Is a conical drill with an apex angle that matches the slope (not shown)
Is cut into the nozzle body 2 from above.

FIG. 2A is a sectional view taken along the line AOB of FIG.
FIG. 2 (b) is a sectional view taken along the line O'B '. As shown in the drawing, in the portion immediately before the notch 6 is formed (middle of the fuel flow path), the gap between the needle valve 1 and the seat portion 5 is constant in the circumferential direction, and the fuel flow path cross-sectional area is Both the main injection hole 4a side and the sub injection port 4b side are equal. On the other hand, in the portion where the notch 6 is formed (the fuel flow path outlet), the gap on the side of the sub injection port 4b is wider than that on the side of the main injection hole 4b by the amount of the notch 6, and the fuel on the side of the sub injection port 4b is increased. Main nozzle hole 4a
Wider than the side. That is, as compared with the fuel flow path exit area on the main injection hole 4a side where the bending of the fuel flow path is liable to increase and the injection amount tends to increase, the injection amount on the sub injection hole 4b side where the bending of the fuel flow path tends to decrease tends to decrease. The fuel flow path exit area increases.

Therefore, the contraction at the fuel passage outlet (section A'O'B ') where the flow passage is most narrowed is reduced on the side of the sub-injection hole 4b, and the fuel flow is partially reduced only on the side of the sub-injection hole 4b. Increase. Therefore, the change in the injection amount due to the steepness of the curve of the fuel flow path is offset by the size of the fuel flow path exit area, and the fuel from each of the main and sub injection holes 4a and 4b is changed without changing the injection hole diameter. The injection amounts become substantially equal. As a result, the distribution of “fuel / air” in the combustion chamber becomes uniform, thereby reducing smoke and improving output.

A fuel injection nozzle 7 shown in FIG. 3 is known as a technique very similar to the present invention (Japanese Utility Model Laid-Open No. 59-21082, etc.). However, this injection nozzle 7
The upper portion 5b of the seat portion 5 on the side of the sub-injection hole 4b is cut out to shorten the throttle passage (l ₂ ) on the side of the sub-injection hole 4b and lengthen the throttle passage (l ₁ ) on the side of the main injection hole 4a. This is a technique for offsetting the change in the injection amount due to the steepness of the curve according to the throttle loss, and has a different technical idea from the invention of the present application.

That is, in the prior art, the gist of the invention of the present application is that "a lower portion 5a of the seat portion 5 on the side of the sub-injection hole 4b is cut off to allow a fuel flow outlet between the needle valve 1 and the seat portion 5 to be cut out. The area is enlarged on the side of the sub injection hole 4b to reduce the contraction of flow on the side of the sub injection hole 4b. " Further, the operation and effect of the prior art can be similarly exerted by the configuration of the present invention, and the present invention further has the above-described operation and effect in a superimposed manner.

[0021]

According to the present invention, as described above, the injection flow rates of the main injection hole and the sub injection hole can be equalized without changing the injection hole diameter.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a Hall type fuel injection nozzle showing one embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating a fuel flow path between a needle valve and a seat portion, wherein FIG. 2A is a cross-sectional view taken along the line AOB of FIG. A'O 'in FIG. 1 representing an exit
It is B 'line sectional drawing.

FIG. 3 is a side sectional view of a Hall type fuel injection nozzle showing the prior art.

FIG. 4 is an explanatory diagram showing a mounting state of a hall-type fuel injection nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Needle valve 2 Nozzle body 3a Shaft core 4a Main injection hole 4b Sub injection hole 5 Seat portion 5a Lower portion of seat portion on sub injection hole side 6 Notch α Angle between main injection hole and shaft core β Sub injection hole and shaft Angle between core

Claims (1)

(57) [Scope of request for utility model registration] 1. A seat portion on which a needle valve which rises and falls inside is provided inside a nozzle body, and a main injection hole having a small angle with an axis and a sub injection hole having a small angle with an axis are provided at a tip of the nozzle body below the seat portion. In the hole-type fuel injection nozzle provided with the injection hole, a cutout portion is formed at a lower portion of the seat portion on the side of the sub injection hole, and an outlet area of a fuel flow path formed between the seat portion and the needle valve is: A hole-type fuel injection nozzle, which is wider on the sub injection hole side than on the main injection hole side by the notch.