JPH0433413Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electromagnetic fuel injection valve used primarily as one of fuel supply means for a vehicle internal combustion engine (hereinafter referred to as engine).

(Background of the invention) In general, as is clear from FIG. 6 showing the cross section of this type of electromagnetic fuel injection valve, the housing A magnetic circuit is constituted by the body 30, the core 2 of the solenoid coil 3, and the armature 7 which receives an electromagnetic attraction force from the core 2. Therefore, the housing body 30 is made of a magnetic material such as electromagnetic stainless steel with high magnetic permeability.

On the other hand, since the fuel injection valve is attached to the cylinder head or intake pipe of the engine, it is easily affected by the heat of the engine through the housing body 30.
A temperature rise also occurs inside the fuel injection valve. If the temperature inside the fuel injection valve exceeds a certain level due to the temperature rise inside the fuel injection valve, the high temperature characteristics of the engine will deteriorate, and there is a risk that a vapor lock phenomenon will occur, especially when the engine is restarted in a high temperature state.

(Prior Art) Various proposals have been made in the past as countermeasures to this problem, and the main ones are as follows.

A type in which a heat insulating material is interposed between the cylinder head of the engine and the housing body of the fuel injection valve (for example, Japanese Utility Model Publication No. 3226/1983,
(See Publication No. 70455, Publication of Utility Model Application No. 58-70457).

A fuel injection valve in which the outer periphery of the housing body is covered with a heat insulating cover and a part of this cover is interposed between the cylinder head and the housing body (for example, Japanese Utility Model Publication No. 56-138151 and Japanese Utility Model Application No. 58-29161) (see official bulletin).

In particular, for fuel injection valves of special internal combustion engines that use alcohol as fuel, cooling water is circulated inside the fuel injection valves, thereby preventing the temperature of the fuel injection valves from rising. (see publication).

(Problems to be Solved by the Invention) In the various prior arts described above, the structure in which a heat insulating material is simply interposed between the cylinder head of the engine and the housing body of the fuel injector is particularly difficult to avoid from the engine. It cannot be expected to suppress the influence of radiant heat on the fuel injection valve. Furthermore, in the above structure in which the outer periphery of the housing body of the fuel injection valve is covered with a heat insulating cover, the heat dissipation effect from the housing body is inhibited by the heat insulating cover, which may even lead to an increase in the temperature of the fuel injector. be.

Although the above configuration in which cooling water is circulated inside the fuel injection valve is an effective means for cooling the fuel injection valve, the structure of the fuel injection valve itself is complicated, and the processing work is also complicated. As a result, new problems arise, including increased costs.

(Means for Solving the Problems) The electromagnetic fuel injection valve of the present invention, for example, as shown in FIG. A magnetic circuit is constituted by a part of the housing body 1, the core 2 of the solenoid coil 3, and the armature 7 which receives an electromagnetic attraction force from the core 2.

A portion 1B (or 1C) of the housing body 1 other than the portion covering the outer periphery of the solenoid coil 3 and other than the portion constituting the magnetic circuit is formed of a heat insulating material with low thermal conductivity. There is.

(Function) According to the above configuration, the portion of the housing body 1 made of a heat insulating material with low thermal conductivity blocks heat conduction from the engine to the fuel injection valve. Further, in the housing body 1, normal thermal conductivity is maintained in the portion that covers the outer periphery of the solenoid coil 3 and the portion that constitutes the magnetic circuit, and the heat radiation function from the solenoid coil 3 and the like is sufficiently performed.

For these reasons, the temperature rise of the fuel injection valve is suppressed, and the high temperature characteristics of the engine are improved.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 5.

First Embodiment First, a first embodiment showing a cross section of an electromagnetic fuel injection valve is shown.
In the figure, a hollow core 2 and a solenoid coil 3 are installed inside a housing body 1 from the right side in FIG. 1, respectively. The outer periphery of this solenoid coil 3 is insulated and covered with a bobbin 4 made of synthetic resin. Further, the rear end portion of the housing body 1 (the right end portion in FIG. 1) and the outer peripheral portion of the core 2 that is exposed to the outside from the housing body 1 are covered with a connector 6 made of synthetic resin. There is. A terminal 5 of the solenoid coil 3 is provided in a part of the connector 6. This terminal 5 is electrically connected to an electric control device (not shown) so that the solenoid coil 3 can be energized and de-energized in response to its input.

In the above housing body 1, the core 2
An annular armature 7 is installed on the front side (left side in FIG. 1) of the armature 7. This armature 7 is configured to receive an electromagnetic attraction force from the core 2 when the solenoid coil 3 is energized. That is, by energizing the solenoid coil 3, a magnetic circuit is constructed by the housing body 1, core 2, and armature 7. The portion 1A covering the solenoid coil 3 is also made of a magnetic material such as electromagnetic stainless steel with high magnetic permeability.

Now, in the above-mentioned housing body 1, the portion 1A that constitutes the magnetic circuit together with the core 2 and the armature 7 is made of a magnetic material such as electromagnetic stainless steel. The other portion 1B except for the portion 1B is made of a heat insulating material with low thermal conductivity, such as Bakelite. The portion 1A constituting the magnetic circuit and the other portion 1B are integrally connected to each other with a packing 18 interposed between the abutting end faces, as shown in FIG.

A nozzle body 9 having a fuel injection hole 10 is incorporated inside a portion 1B of the housing body 1 other than the portion 1A constituting the magnetic circuit. Further, a sleeve-shaped adapter portion 1C that covers the outer periphery of the injection hole 10 is formed integrally with a portion 1B of the housing body 1 made of a heat insulating material, and this adapter portion 1C is also a part of the housing body 1 as a result. Part 1A that constitutes the magnetic circuit
This is the other part.

A guide hole 17 communicating with the injection hole 10 is formed in the axial center of the nozzle body 9 .
This guide hole 17 also communicates with the inside of the hollow core 2, and these eventually constitute a fuel passage 15 inside the fuel injection valve. In addition, this core 2
A straight 16 is incorporated at the entrance of the fuel passage 15 at the rear end of the fuel passage 15 .

In the guide hole 17 of the nozzle body 9, a cylindrical slide body 12 having a ball-shaped valve body 13 at its tip is installed so as to be slidable in the left-right direction in FIG. The rear end of the slide body 12 is connected to the armature 7 by press fitting or the like. In addition, slide body 1
2 receives the elasticity of the valve spring 14,
Normally, the injection hole 10 is kept closed by the valve body 13.

The above fuel injection valve is attached to a cylinder head 21 of a cylinder block 20, as shown in FIG. In other words, the cylinder head 21
An intake passage 22 communicating with each cylinder of the cylinder block 20 is formed in the cylinder block 20, and the fuel injection valve injects fuel from the injection hole 10 of the nozzle body 9 into the intake passage 22 of the cylinder head 21. installed. Then, the cylinder head 21 and the adapter part 1C of the fuel injection valve
An insulator 24 is interposed between the cylinder head 21 and the outer periphery to suppress heat transfer from the cylinder head 21 to the fuel injection valve.

Further, in FIG. 2, a delivery pipe 25 for supplying fuel to the fuel passage 15 is connected to the fuel injection valve, and a retainer portion 26 of the delivery pipe 25 is connected to the cylinder head 21 by bolts 27. Fixed in some parts. Note that an intake pipe 28 is connected to the intake passage 22 of the cylinder head 21, and between this intake passage 22 and the cylinder of the cylinder block 20,
Intake valve 2 that controls communication and isolation between these
3 is provided.

In the electromagnetic fuel injection valve configured as described above, fuel to which a predetermined pressure is applied is supplied into the internal fuel passage 15 from the delivery pipe 25 shown in FIG. 2 through the strainer 16. When the solenoid coil 3 is not energized, the slide body 12 receives the elastic force of the valve spring 14, and as described above, the valve body 13 holds the injection hole 10 of the nozzle body 9 in a closed state. There is. When the solenoid coil 3 is energized, the electromagnetic attraction force of the core 2 causes the armature 7, together with the slide body 12 and the valve body 13, to move toward the right in FIG. 1 against the elasticity of the valve spring 14. move slightly to
As a result, the valve body 13 is connected to the injection hole 1 of the nozzle body 9.
Away from the sheet surface on the 0 side, the injection hole 10
The intake passage 2 of the cylinder head 21 shown in FIG.
Fuel is injected into the 2.

As shown in FIG. 2, an insulator 24 is interposed between the adapter portion 1C of the fuel injection valve and the cylinder head 21 to provide a heat insulating function.
Because temperatures reach 80°C to 90°C, the fuel injector is easily affected by heat transfer or radiant heat from this temperature.

However, in this embodiment, as described above, when the solenoid coil 3 is energized in the housing body 1 of the fuel injection valve, the portion 1B (the adapter portion 1C) is made of a heat insulating material such as Bakelite, which has low thermal conductivity. Therefore, heat transfer or radiant heat from the cylinder head 21 to the fuel injection valve is blocked, and temperature rise of the fuel injection valve is suppressed. As a result, the rise in temperature of the fuel supplied to the fuel passage 15 inside the fuel injection valve is also suppressed, the high temperature characteristics of the engine are improved, and the vapor lock phenomenon is particularly prevented when the engine is restarted in a high temperature state.

Second Embodiment In the embodiment shown in FIG. 3, the shape of the adapter portion 1C, which is integrally formed with the portion 1B made of a heat insulating material such as Bakelite, is changed. In other words, the inner peripheral surface 1 of this adapter portion 1C
The shape of Ca is formed into a conical shape within a range that does not interfere with fuel injection from the injection hole 10 of the nozzle body 9. As a result, heat transfer from the cylinder head 21 to the nozzle body 9 can be more effectively blocked, and the cylinder head 21
Radiant heat from the intake passage 22 to the nozzle body 9 can also be effectively suppressed.

Third Embodiment The embodiment shown in FIG. 4 covers the outer periphery of the nozzle body 9 on the fuel injection hole 10 side, and
Only the adapter portion 1C, which can most effectively block heat conduction from the fuel injection valve to the fuel injection valve, is made of a heat insulating material such as Bakelite, and the housing body 1 is made of a magnetic material such as electromagnetic stainless steel. This is what I did. Also in this third embodiment, heat transfer from the cylinder head 21 to the fuel injection valve can be sufficiently blocked.

Fourth Embodiment The embodiment shown in FIG. 5 is a further improvement of the third embodiment, in which the adapter portion 1C is made of a heat insulating material and the magnetic circuit is formed in the housing body 1. The portion 1B other than the portion 1A is made of a material with high thermal conductivity, such as aluminum. Therefore, this fourth
In the embodiment, in addition to the heat insulation function at the adapter part 1C made of a heat insulating material, the heat radiation function at the part 1B other than the magnetic circuit component part 1A of the housing body 1 makes the temperature rise of the fuel injection valve more effective. It will be suppressed.

In addition, in the above-mentioned second to fourth embodiments, parts that are considered to have the same or equivalent configuration as the first embodiment are shown in the respective drawings (Figs. 3 to 4).
5), the same reference numerals as in FIG. 1 are given, and redundant explanations will be omitted.

(Effects of the invention) In this way, the present invention improves the insulation function between the engine cylinder head and the fuel injection valve installed there, and also improves the heat radiation function from the solenoid coil inside the fuel injection valve. Since the temperature of the fuel being supplied to the inside of the fuel injection valve can be suppressed from increasing. This improves the high-temperature characteristics of the engine, and in particular prevents the vapor lock phenomenon when restarting the engine at high temperatures.

[Brief explanation of drawings]

1 to 5 show embodiments of the present invention.
The figure is a sectional view of an electromagnetic fuel injection valve, Figure 2 is a partial sectional view showing how the fuel injection valve is attached to the cylinder head on the engine side, and Figures 3 to 5 are a second embodiment of the present invention. - FIG. 4 is a cross-sectional view showing the fourth embodiment in correspondence with FIG. 1; FIG. 6 is a sectional view of a conventional general fuel injection valve. 1...Housing body, 1A...Parts forming the magnetic circuit, 1B, 1C...Parts other than the parts forming the magnetic circuit, 2...Core, 3...Solenoid coil, 7... Armature.

Claims (1)

[Claim for Utility Model Registration] By energizing the solenoid coil built into the housing body, a part of the housing body, the core of the solenoid coil, and the armature that receives an electromagnetic attraction force from this core. The electromagnetic fuel injection valve has a magnetic circuit formed by An electromagnetic fuel injection valve made of a heat insulating material with low conductivity.