JPH04234565A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent a fuel injecting direction from becoming unstable by large vibration of a nozzle, which forms an air-fuel mixture passage and is vibrated on a large scale due to engine vibration in a fuel injection device equipped with an air assist device in the present invention. CONSTITUTION:In a fuel injection device of an internal combustion engine equipped with an air assist device to transform fuel injected from a fuel injection valve 1 into particulates by means of assist air, a long nozzle 11 having an air-fuel mixture passage 17 which is situated more downstream in the injecting direction than a fuel injecting port 15 and in which injection fuel and the assist air supplied from the air assist device are mixed together, is installed on the tip of an injection valve, and the tip part of this long nozzle 11 is also supported, for example, with a port diaphragm 8.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] In order to improve the combustion and fuel efficiency of an internal combustion engine, the present invention provides an air assist device that atomizes fuel injected from a fuel injection valve using an injected air flow.
The present invention relates to a fuel injection device for an internal combustion engine.

0002

2. Description of the Related Art In order for an internal combustion engine to burn fuel efficiently while using less fuel, it is first necessary to supply fuel to a combustion chamber in a state in which it is most easily combustible. In recent years, for internal combustion engines equipped with fuel injectors, in order to promote atomization of the fuel injected from the fuel injectors, air from the outside is pumped into the fuel injection ports of the fuel injectors. A fuel injection device has been proposed that is equipped with an air assist device that vigorously jets the injected fuel toward the vicinity (hereinafter referred to as the nozzle) and promotes atomization of the injected fuel. A fuel injection device has been proposed in which a fuel injection valve is equipped with a cylindrical member (long nozzle) that guides the fuel up to the point (Japanese Utility Model Publication No. 11364/1983).

0003

[Problems to be Solved by the Invention] However, in a fuel injection device in which a long nozzle as described above is attached to the tip of a fuel injection valve, the main body of the fuel injection valve is installed in, for example, a cylinder head, and the long nozzle is inserted from there. It extends into the intake port and near the intake valve, and the long nozzle tip is not supported. Therefore, when the internal combustion engine is operating, the nozzle tip vibrates with a large amplitude due to the vibration of the engine body, making it impossible to inject fuel toward the desired location, and for example, increasing the amount of fuel adhering to the inner wall of the intake port. As a result, problems such as a decrease in air-fuel ratio control accuracy occur.

[0004] In view of the above-mentioned problems of the prior art, the present invention
It is an object of the present invention to provide a fuel injection device capable of injecting fuel toward a desired position even when vibrations occur in an engine.

[0005]

[Means for Solving the Problems] According to the present invention, in order to solve the above-mentioned problems, there is provided a fuel injection device for an internal combustion engine that includes an air assist device that atomizes fuel injected from a fuel injection valve with air. A nozzle having a mixture passage that mixes the injected fuel with the air ejected from the air assist hole is mounted on the downstream side of the fuel injection port of the fuel injection valve in the injection direction, and the nozzle is inserted from the outside of the intake port. A fuel injection device for an internal combustion engine is provided, characterized in that a nozzle support means is inserted into an intake port and further supports a nozzle tip.

[0006]

[Operation] Even if the engine vibrates, the tip of the nozzle is supported by the nozzle support means, so the opening of the mixture passage
That is, the vibration amplitude of the air-fuel mixture injection port of the device does not increase, and fuel can be injected at the desired position.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described with reference to the drawings. FIG. 1 shows a cross section of a cylinder equipped with a fuel injection device according to the present invention, and FIG. 2 shows a cross section taken along line II-II in FIG. In these figures, 1 is a cylinder, 2 is an intake valve, 3 is an exhaust valve, and 4 is a spark plug.

Reference numerals 5 and 6 indicate intake ports and exhaust ports formed in the cylinder head 7 corresponding to the intake valve 2 and exhaust valve 3, respectively, and 8 indicates a port partition wall separating the two intake ports 5. It is.

According to this embodiment, for an engine having two intake ports 5 per cylinder as described above, the fuel injection valve 10 constituting the fuel injection device 9 of the present invention is installed in the port partition wall. It is mounted in the cylinder head 7 above the cylinder head 8. This fuel injection valve 10 is equipped with a long nozzle 11 at its tip for mixing assist air and injected fuel, and the tip of the long nozzle 11 is for distributing the air-fuel mixture to both intake ports 5. , two mixture injection ports 12 are formed.

Further, as shown in FIG. 2, this long nozzle 11 is installed so as to descend from the cylinder head 7 above the port partition 8 to the port partition 8, and has two air-fuel mixture injections provided at its tip. The ports 12 are exposed in both intake ports 5 and are arranged in the port partition wall at a predetermined position and at a predetermined angle of inclination so that the air-fuel mixture through the respective air-fuel mixture injection ports 12 is injected toward the respective intake valves 2. 8.

FIG. 3 is a sectional view of the fuel injection valve 10 and the long nozzle 11 taken along the line III--III in FIG. In this figure, reference numeral 13 constitutes an air assist device, which supplies assist air from the device body (not shown) to the fuel injection valve 1.
Air delivery distributed around 0, 14 is air delivery 1
This is an assist air supply section that supplies pressurized air to the air pump 3.

The fuel injection valve 10 has a fuel injection port (nozzle) 15 on its central axis A, and a needle valve 16 is provided inside the main body of the fuel injection valve 1 so as to be able to reciprocate in the direction of the central axis A. It is installed.

Inside the long nozzle 11 attached to the tip of the fuel injection valve 10, there is a mixture passage 1 extending downstream from the injection port 15 along the central axis A in the fuel injection direction.
7 is formed, and furthermore, an air assist hole 1 is formed which communicates this mixture passage 17 with the internal space 18 of the air delivery 13.
9 is formed. That is, the mixture passage 17 uniformly mixes the fuel injected from the nozzle 15 of the fuel injection valve 1 and the assist air supplied from the air assist device.
The fuel is further atomized.

According to this embodiment, the mixture passage 17 is branched into two passages 17' near the tip of the long nozzle 11, and opens through the two mixture jet ports 12 as described above. This branch passage 17' is arranged along the central axis so that the atomized fuel flowing through the mixture passage 17 is divided equally, and in the case of this embodiment, so that it is injected toward the two intake valves 2. It is inclined at a predetermined angle with respect to A.

Further, according to this embodiment, most of the long nozzle 11 is supported by the cylinder head 7 as shown in the figure, and in particular, the tip thereof is connected to the perforation 2 formed in the port partition wall 8.
The nozzle tip is exposed into the intake port 5 from the hole 2.
0, the tip of the long nozzle 11 will not vibrate greatly due to engine vibrations. By optimizing the opening position and the air-fuel mixture injection angle, the air-fuel mixture can be naturally injected to the targeted position (usually around the intake valve 2) even during engine operation.

As described above, in the embodiment described above, when the thickness of the port partition wall 8 is larger than the diameter of the long nozzle 11, the perforation 20 is formed in the port partition wall 8 to secure the air-fuel mixture injection port as a fuel injection device. As an example, if the minimum thickness of the port partition wall is smaller than the long nozzle diameter, it will naturally be exposed in the intake port without forming a hole, and the air-fuel mixture jet port can be secured.

FIG. 4 shows a modification of the above embodiment, in which a recess 21 for supporting the nozzle tip is formed at the starting end 8a of the port partition wall 8 separating the respective intake ports 5, and the long nozzle 11 is supported at this position. This suppresses vibrations.

Although the present invention has been described above using an example in which the nozzle support means is a port partition wall, the nozzle support means is not limited to this, and for example, the inner wall surface of an independent port may be used as the nozzle support means. Alternatively, a configuration may be adopted in which a nozzle support member is newly installed within the intake port.

[0019] The illustrated embodiments have a common feature in that there is no part that communicates each intake port 5 downstream of the air-fuel mixture jet port 12, so there is no intake air flow between the ports, and the conventional fuel Compared to an injection device (the mixture jet is located upstream of the intake from the beginning of the port partition wall),
This has the effect of stabilizing the directionality of fuel spray and reducing fuel adhesion to the inner wall of the port.

Therefore, when such a nozzle installation is applied to an internal combustion engine having a structure in which one intake port is provided with an intake control valve 22 and the other intake port is a swirl port as shown in FIG. A large swirl effect is obtained when the control valve is closed, improving lean limit performance and
EGR limit performance can be improved.

[0021]

As explained above, according to the present invention, even when the engine vibrates, the tip of the nozzle is supported by the nozzle support means, so that the opening of the mixture passage, that is, the mixture injection port of the device, is The vibration amplitude does not increase, and the fuel can be injected at a desired set position, reducing the amount of fuel adhering to the port wall and improving the transient performance of the engine.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a cylinder equipped with a fuel injection device of the present invention.

FIG. 2 is a cross-sectional view of a cylinder taken along line II-II in FIG. 1;

FIG. 3 is a sectional view of the tip portion of the fuel injection device taken along the line III-III in FIG. 2;

FIG. 4 is a vertical cross-sectional view of a cylinder as a modification of the embodiment shown in FIG. 1;

[Explanation of symbols]

5...Intake port 8...Port partition 10...Fuel injection valve 11...Long nozzle 13...Air delivery (part of air assist device) 15...
Fuel injection port (spout) 17...Mixture passage

Claims (1)

[Claims] 1. A fuel injection device for an internal combustion engine including an air assist device that atomizes fuel injected from a fuel injection valve with air, wherein the injected fuel and A nozzle having a mixture passage for mixing with air ejected from an air assist hole is installed, the nozzle is inserted from outside the intake port to inside the intake port, and a nozzle support means is further provided to support the tip of the nozzle. A fuel injection device for an internal combustion engine characterized by: