JP2002257008A - Fuel injection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection system constituted so that space for a fuel passage and a cooling water passage is enlarged, in the fuel injection system including a needle valve that is displaced by pressure of fuel fed from a fuel injection pump to open a fuel injection hole, and a spring that urges the needle valve in the direction of closing the fuel injection hole. SOLUTION: The fuel injection system comprises: the needle valve 3 that is displaced by the pressure of the fuel fed from the fuel injection pump to open the fuel injection hole; and the spring 6 that urges the needle valve 3 in the direction of closing the fuel injection hole. The spring chamber storing the spring 6, and the needle valve 3 are disposed at an eccentric position from an axial center A-A of a fuel injection valve body 4, so that the space for the fuel passage 8 and the water passage 2 is enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device of the type having a needle valve which is displaced by the pressure of fuel oil supplied from a fuel injection pump to open an injection hole.

[0002]

2. Description of the Related Art In a fuel injection device of a type having a needle valve which opens an injection hole by being displaced by the pressure of fuel oil supplied from a fuel injection pump, a spring for urging the needle valve in a direction to close the injection hole is provided. Many nozzles are provided in the nozzle, such as a spring chamber for accommodating the fuel, a fuel passage for guiding fuel oil to the needle valve, a water passage for guiding cooling water for cooling when the temperature of the fuel is high or water for water injection.

FIG. 3 shows a structural example of a conventional fuel injection device. In FIG. 3, reference numeral 1 denotes a nozzle, and fuel oil is guided to a fuel oil chamber 15 in the nozzle 1 through a fuel passage 2.
The needle valve 3 that closes the needle valve seat 17 serving as a fuel oil supply port to the fuel ejection hole 16 at the tip of the nozzle 1 is opened by the fuel oil pressure in the fuel oil chamber 15 to eject fuel oil. I have.

[0004] A spring chamber 5 is formed in the axial center of the fuel injection valve body 4, and a spring 6 is housed therein. The valve seat 17 is closed. Further, the fuel injection valve body 4 includes:
A water passage 8 is formed.

FIG. 4 shows the positional relationship between the various holes in the fuel injection valve main body 4. As shown in FIG. 4, the fuel injection valve body 4 has a large-diameter spring chamber 5 at an axial center portion, and has a structure in which a fuel passage 2, a water passage 8 and the like are arranged in an annular portion therearound. . In FIG. 3, reference numeral 12 denotes a spring sheet, 1
3 denotes a spring adjusting screw, and 14 denotes a cap nut.

[0006] On the other hand, since the fuel injection valve must be mounted in a limited space of the internal combustion engine, the outer diameter is limited. Therefore, the fuel injection valve has a structure in which the above-described various holes are close to each other, and stress concentration and the like are likely to occur, and it is difficult to ensure reliability.
In particular, the spring 6 for urging the needle valve in the direction to close the needle valve seat 17
Because the diameter of the spring chamber 5 that accommodates the spring chamber 5 is large, the size of other holes arranged around the spring chamber 5 is restricted, and for example, the size of the water passage for the cooling water cannot be sufficiently taken. There was a problem.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a needle valve which is displaced by the pressure of fuel oil supplied from a fuel injection pump to open an injection hole, and biases the needle valve in a direction to close the injection hole. An object of the present invention is to provide a fuel injection device having a spring in which a space for a fuel passage and a water passage can be widened.

[0008]

According to the present invention, there is provided a spring chamber for accommodating a spring which biases a needle valve in a direction to close an injection hole, and a needle valve which is eccentric from an axis of a fuel injection valve body. Provided is a fuel injection device having a structure provided by being provided.

In the fuel injection device of the present invention configured as described above, the spring chamber accommodating the spring for biasing the needle valve and the needle valve are provided eccentrically from the axis of the fuel injection valve main body. The space provided for the passage and the water passage such as the cooling water can be widened, and the diameter of the passage can be increased. For this reason, according to the fuel injection device of the present invention, a situation where the flow velocity of the fuel is suppressed does not occur, and the fuel valve can be cooled with a sufficient amount of cooling water.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel injection device according to an embodiment of the present invention will be specifically described. In the fuel injection device according to the present embodiment, as shown in FIG. 1, the spring chamber 10 and the needle valve 3 are provided at positions eccentric from the axis A-A of the fuel injection valve main body 4.

Therefore, as shown in FIG. 2 showing a section taken along the line II-II in FIG. 1, the spring chamber 10 is eccentric from the axis of the fuel injection valve main body 4, and the fuel passage 2 and the cooling water The space provided for the water passage 8 is increased, and the water passage 8 can be provided in a required size. The other configuration is the same as the configuration of the conventional fuel injection device described with reference to FIG. 3, and the description is omitted.

As described above, the present invention has been specifically described based on the illustrated embodiments. However, the present invention is not limited to these embodiments, and specific structures within the scope of the present invention shown in the claims are set forth. Needless to say, various changes may be made to the configuration.

For example, in the above embodiment, the fuel passage is
Although two cooling water passages are provided, the number of cooling water passages is not limited to these, and the arrangement is not limited to that shown in FIG.

[0014]

As described above, the present invention has a structure in which a spring chamber for accommodating a spring for biasing a needle valve in a direction to close an injection hole and a needle valve are provided eccentrically from the axis of the fuel injection valve body. The present invention provides a fuel injection device. In the fuel injection device of the present invention configured as described above, the spring chamber for accommodating the spring for biasing the needle valve and the needle valve are provided eccentrically from the axis of the fuel injection valve main body. The space provided for the water passage such as the above can be widened, and the diameter of the fuel passage and the water passage can be increased.

Therefore, according to the fuel injection device of the present invention,
The situation where the flow rate of the fuel is suppressed does not occur, and the fuel valve can be cooled with a sufficient amount of cooling water.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a tip portion of a fuel injection device according to an embodiment of the present invention.

FIG. 2 is a transverse sectional view taken along the line II-II of FIG.

FIG. 3 is a longitudinal sectional view of a tip portion of a conventional fuel injection device.

FIG. 4 is a transverse sectional view taken along the line IV-IV in FIG. 3;

[Explanation of symbols]

 Reference Signs List 1 nozzle 2 fuel passage 3 needle valve 4 fuel injection valve body 5 spring chamber 6 spring 7 push rod 8 water passage 10 spring chamber 12 spring seat 13 spring adjustment screw 14 bag nut 15 fuel oil chamber 16 fuel ejection hole 17 needle valve seat

Claims (1)

[Claims] 1. A fuel injection device comprising: a needle valve displaced by the pressure of fuel oil supplied from a fuel injection pump to open an injection hole; and a spring for urging the needle valve in a direction to close the injection hole. A fuel injection device, wherein a spring chamber accommodating the spring and the needle valve are provided eccentrically from an axis of a fuel injection valve body.