JPH08261107A - Fuel injection device - Google Patents

Abstract

PURPOSE: To prevent the occurrence of leakage attributable to ignition noise, and to eleminate the malfunction due to the leakage, in the fuel injection device in which an ignition plug has been integrally provided in the fuel ignition valve, by reducing the noise level of ignition noise on the harness. CONSTITUTION: In a fuel injection device provided both with a fuel injection valve in which a valve 10 having an armature 3, a valve seat 5 that is opened or closed by the valve 10, a coil 42 that attracts the armature 3 by electrification, and a harness 43 that has been electrically connected to the coil 42 are incorporated inside a housing 20, and with an ignition plug that has been integrally incorporated in the fuel injection valve making a center electrode of the valve seat 5; the harness 43 is covered with a shielding material 59 consisting of a material excellent in conductivity.

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 mainly used in a vehicle internal combustion engine (also called an engine).

[0002]

2. Description of the Related Art A conventional fuel injection device is shown in FIG.
As shown in a sectional view in FIG. 1, there is a fuel injection valve that directly injects fuel into a combustion chamber of an engine, and an ignition plug integrally formed with the fuel injection valve. Note that hatching showing a cross section is omitted in FIG. In the fuel injection valve, high-pressure fuel supplied from a fuel tank (not shown) under a predetermined pressure is supplied from a fuel inlet 1 of a housing sub-assembly (corresponding to a housing in the present invention) 20. It reaches the inside of the valve seat 5 through the internal fuel passage. However, when the valve 10 closes the injection port 5a of the valve seat 5 due to the elasticity of the valve spring 9, fuel is not injected. When the coil 42 is energized, the suction force of the core 2 acting on the armature 3 opens the valve 10 to inject fuel.

Further, in the ignition plug, the high voltage from the ignition coil is transmitted to the valve seat 5 through the high tension cord 6, the screw stopper 7, the set screw 8, the pipe 61, the valve spring 9 and the valve 10, and the valve seat. An edge portion 5b having a center electrode 5 and a ground electrode facing it (also referred to as a GND electrode)
A spark discharge is generated between In addition to the above, a fuel injection device of this type may be, for example, the actual open shaft 63-1547.
There is one disclosed in Japanese Patent Laid-Open No. 60.

The coil 4 in the fuel injection system of FIG.
The body sub-assembly 21 in which 2 and the core 2 are assembled is shown in an enlarged view in FIG. 7. In FIG. 7, the coil 42 is electrically connected to the terminal 45 by soldering in the space 16 a above the bobbin 16.
The terminal 45 projects from the upper end surface of the bobbin 16 and passes through the flange portion 2 a of the core 2 and the second block 1
5 is recessed in the recess 15a. In the recess 15a, the harness 43 drawn through between the second block 15 and the spring guide 41 is electrically connected to the terminal 45 by soldering. The coil 42, the core 2 and the like are fitted in the yoke 17 which is inserted into the housing sub-assembly 20. The yoke 17 and the housing sub-assembly 20 are electrically connected to the cap 11 having the ground electrode 12 and correspond to a ground side member.

[0005]

According to the fuel injection device described above, the fuel injection valve has the same structure as a general fuel injection valve having no spark plug, although the spark plug is integrally formed. Ignition noise is not taken. That is, as shown in FIG. 7, the harness 43 is formed of an insulated wire in which a conductive wire 43a made of, for example, a mild steel stranded wire is covered with an insulating layer 43b made of a radiation-crosslinked vinyl insulator. A sectional view taken along the line AA of FIG. 5 is shown in FIG. The insulating layer 43b of the harness 43 may be insufficient to reduce the noise level of the ignition noise on the conductor 43a.
Therefore, when the ignition noise of the spark plug is applied to the harness 43 (specifically, the lead wire 43a), for example, an electric connection portion including the terminal 45 between the coil 42 and the harness 43 leaks to the portion of the ground side member adjacent thereto. May occur, resulting in malfunction of the fuel injection device.

The technical problem to be solved by the present invention is as follows.
In a structure in which a spark plug is integrated with a fuel injection valve, the noise level of the ignition noise on the harness is reduced to prevent the occurrence of leaks due to the ignition noises and eliminate malfunctions due to the leaks. It is to provide a fuel injection device capable of performing

[0007]

In order to solve the above-mentioned problems, the present invention according to claim 1 electrically connects to a valve having an armature, a valve seat opened and closed by the valve, a coil for attracting the armature by energization, and the coil. In a fuel injection device including a fuel injection valve in which a harness is incorporated in a housing, and an ignition plug integrally formed with the fuel injection valve with the valve seat as a central electrode, the harness is made of a material excellent in conductivity. Is a fuel injection device covered with a shield material.

[0008]

According to the fuel injection device of the first aspect, the noise level of the ignition noise on the harness is lowered by shielding the ignition noise of the ignition plug by the shield material covering the harness.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. Since this example is a modification of a part of the above-mentioned conventional example, the same or equivalent parts are designated by the same reference numerals. The fuel injection device shown in cross section in FIG. 1 is roughly divided into a housing subassembly 20 and
It is composed of a body sub-assembly 21, a valve sub-assembly 4 and a cap sub-assembly 23 which are assembled to the housing sub-assembly 20. In FIG. 1, hatching showing a cross section is omitted.

The housing sub-assembly 20 has a substantially hollow cylindrical shape, and the inner and outer cylinders 34 and 3 are inserted in the inner and outer double layers.
It consists of 5. Specifically, the inner cylindrical body 34 made of SUS304 material is inserted into the upper cylindrical portion of the outer cylindrical body 35 made of SUS magnetic material. An appropriate number of grooves 34a are provided on the outer peripheral surface of the lower half of the inner cylindrical body 34 along the axial direction. Further, an appropriate number of grooves 35a are provided on the outer peripheral surface of the upper end portion of the outer tubular body 35 along the axial direction. These groove 34a,
The reference numeral 35a forms a fuel passage that is axially communicated with each other by being inserted into each other and is open at both axial ends (upper and lower ends in the drawing). Further, the outer cylinder body 35 is provided with a stepped and expanded flange member 60 fixed to the upper end portion thereof.

The inner cylindrical body 34 is formed by the flange member 60.
A ring-shaped joint part 37 made of a SUS material is rotatably fitted in the annular space formed around it with a gap maintained between the lower surface of the annular joint part 37 and the bottom surface of the annular space. . The joint component 37 is fixed to the inner cylindrical body 34 by tightening a fixing nut 38 made of SUS303 material. The joint component 37 is formed with a fuel intake port 1 having one end opening to the end face of the connecting portion 36 protruding to the outer side surface and the other end opening to the lower face. A strainer 39 is incorporated in the connecting portion 36. Further, a fuel supply pipe is connected to the connecting portion 36. In addition, the joint component 37,
An O-ring 3 for maintaining airtightness between the cylindrical bodies 35, 34
0 and 31 are provided respectively.

As shown in the sectional view of FIG. 3, the body sub-assembly 21 incorporated in the housing sub-assembly 20 has a second block 15 made of a ring-shaped SUS304 material and a second block thereof. A substantially hollow cylindrical electrical insulating material (also referred to as an insulator), in which 15 is insert-molded in the central portion, for example, a spring guide 41 made of polyphenylene sulfide resin (also referred to as PPS resin), and a substantially hollow fitted to the spring guide 41. A core 2 made of a cylindrical magnetic material, and a bobbin 16 made of an electrically insulating material fitted to the core 2, for example, PPS resin.
And the coil 42 wound around the bobbin 16 in multiple layers
And a ring-shaped SUS3 fitted to the lower end of the core 2.
The first block 14 made of 04 material is fitted in the yoke 17 made of SUS magnetic material having a substantially hollow cylindrical shape. The spring guide 4
1 is provided with an O-ring 27 for maintaining airtightness with the core 2, and the first block 14 is provided with O-rings 25, 26 for maintaining airtightness with the yoke 17 and the core 2, respectively. There is. The outer peripheral surface of the coil 42 is covered with a coating layer 63 of an electrically insulating material.

An appropriate number of grooves 17a are provided on the outer peripheral surface of the yoke 17 along the axial direction. This groove 1
7a is open to the upper end surface of the yoke 17, and the lower end thereof is connected to a communication hole 44 penetrating in the yoke radial direction at the lower end portion of the yoke 17.

In FIG. 3, the coil 42 is the bobbin 1.
Electrical connection is made by soldering to the terminal 45 in the space 16a above the 6. Terminal 45
It protrudes from the upper end surface of the bobbin 16 and is inserted into the recess 15 a of the second block 15 through the flange portion 2 a of the core 2.

On the other hand, 2 for connecting to the coil 42
Each coil connection side end of the harness 43 of the book is located between the second block 15 and the spring guide 41.
5 is drawn into the recess 15a. This harness 4
The lead wire 43a at the end of each coil connection side of No. 3 is the recess 15a.
Is electrically connected to the connection end of the coil 42 by soldering. The harness 43 is formed of an insulated wire in which a conductive wire 43a made of, for example, a mild steel stranded wire is covered with an insulating layer 43b made of a radiation-crosslinked vinyl insulator. Further, as shown in the perspective view of FIG. 4, a shield material 59 made of a material having excellent conductivity, such as copper foil or aluminum foil, is spirally formed on the two harnesses 43 and overlaps the side edge portions. It is wrapped while making it.

The body sub-assembly 21 is inserted in the lower half of the housing sub-assembly 20 as shown in FIG. With this insertion, the shield material 59
The harness 43 wound around the housing sub-assembly 20
It is pulled out through the inside. BB of FIG.
A line cross section is shown in FIG. The lead-out end of the harness 43 is electrically connected to an electronic control unit (also referred to as an ECU) (not shown), and the coil 42 receives an input from the electronic control unit to energize or deenergize it.

The groove 17a of the yoke 17 forms a fuel passage communicating in the axial direction by being inserted into the outer cylinder 35. This fuel passage communicates with the fuel passage formed by the grooves 34a, 35a in the housing sub-assembly 20 through a space surrounded by the inner cylinder 34, the outer cylinder 35, the yoke 17 and the second block 15. The upper end of the second block 15 is fitted in the inner cylindrical body 34. The second block 15 is provided with an O-ring 28 that maintains airtightness with the inner cylindrical body 34.

At the upper end of the spring guide 41,
A set screw 8 and a set screw stopper (called a screw stopper) 7 made of SUS303 material are sequentially screwed. Specifically, the set screw 8 has a groove 8a.
The head itself having is screwed to the spring guide 41. A pipe 61 made of SUS303 material that comes into contact with a valve spring 9 described later is rotatably fitted into the shaft end of the set screw 8. Pipe 61
Rotates relative to the set screw 8 when the set screw 8 is screwed in, and prevents twisting due to rotation of the valve spring 9. The set screw 8 is provided with an O-ring 29 that keeps airtightness with the spring guide 41.

The lower end of the screw stopper 7 is screwed onto the spring guide 41. The connection terminal 6a of the high tension cord 6 is electrically connected to the rectangular groove-shaped socket portion 7a formed on the upper end portion of the screw stopper 7. A filling material 46 such as epoxy resin for sealing the space around the high tension cord 6 and the harness 43 is loaded on the upper end of the inner cylindrical body 34.

The valve sub-assembly 4 incorporated in the lower end portion of the body sub-assembly 21 includes a shaft-shaped valve 10 made of SUS440C material and a valve support made of an electric insulating material such as PPS resin in which the upper end portion of the valve 10 is insert-molded. The body 48 and the armature 3 made of a magnetic material and insert-molded on the outer periphery of the central portion of the valve support 48. The upper half of the valve support 48 is formed in a hollow cylindrical shape.

The valve sub-assembly 4 is fitted in the body sub-assembly 21 so as to be vertically movable. Specifically, after the valve spring 9 made of SUS304 material is inserted into the spring guide 41, the valve support 48 is inserted into the spring guide 41 with the tubular portion of the valve support 48 fitted to the lower end of the valve spring 9. It is fitted inside. The armature 3 is located in the lower end portion of the yoke 17, the upper end surface thereof faces the lower end surface of the core 2, and the core 2 is energized when the coil 42 is energized.
Receives suction from. Further, the communication hole 44 of the yoke 17
The open end of the valve communicates with the space around the valve support 48.

The cap sub-assembly 23 incorporated in the lower end portion of the housing sub-assembly 20 has a substantially hollow cylindrical shape and a valve seat 5 made of a stainless alloy material having a nozzle 5a at its lower end and a substantially hollow cylindrical shape. And the inside of which the valve seat 5 is inserted and the inside of which the valve seat 5 is screwed, and a ceramic insulating cover 13 and a substantially hollow cylindrical shape, and the inside of which the insulating cover 13 is inserted. The cap 11 is made of a SUS material.

The lower end of the cap 11 is made of a Ni alloy material and has a lower end edge 5b of the valve seat 5.
The ground electrode 12 is provided to point to. On the outer peripheral surface of the cap 11, a male screw 11a for screwing on a cylinder head (not shown) of the internal combustion engine is formed. The valve seat 5 is provided with an O-ring 19 for maintaining airtightness between the valve seat 5 and the insulating cover 13.
The O-ring 24 that keeps airtightness with the cap 11
Is provided. The upper edge of the cap 11 is crimped to the insulating cover 13 via an O-ring 32.

The cap sub-assembly 23 is incorporated in the housing sub-assembly 20, and more specifically, the valve 10 is slidably inserted into the valve seat 5, and the cap 11 is provided at the lower end of the outer cylinder 35. And is fixed by laser welding. The valve sub-assembly 4 is constantly urged downward in the drawing by the elasticity of the valve spring 9, and the valve 10 is held in a state of closing the injection port 5a of the valve seat 5.

A cylindrical ring tube 18A made of metal, for example, SUS303 material is inserted into the cap 11 and faces the yoke 17. This ring cylinder 18A
A ring-shaped adjustment plate 22A made of metal, for example, SUS440C-based material is interposed between and the yoke 17 opposed thereto. The opening / closing stroke of the valve 10 is finely adjusted by adjusting the plate thickness of the adjusting plate 22A. The inner diameter of the upper end portion of the insulating cover 13 is formed larger than that of the large diameter portion of the valve support body 48. A fuel passage communicating with the fuel cell is formed.

The O-rings 19 and 2 used for the above-mentioned respective parts
Nos. 4 to 32 are all made of a fluororubber material. Further, the material specified for each member is not limited to that, and may be any material satisfying the condition required for each member.

First, the operation of the fuel injection valve in the fuel injection device will be described. The fuel supplied from a fuel tank (not shown) in a state where a predetermined pressure is applied is filtered by the strainer 39 of the fuel inlet 1 and then reaches the inside of the valve seat 5 through the fuel passage. However, since the valve 10 is held by the elasticity of the valve spring 9 in a state where the injection port 5a of the valve seat 5 is closed, fuel injection from this injection port 5a does not occur.

When the coil 42 is energized by the input of an electric signal from the electronic control unit, the valve sub-assembly 4 is retracted by the attraction force of the core 2 acting on the armature 3. As a result, the injection port 5a of the valve seat 5 is opened, and fuel is injected from here. And coil 42
When the suction signal of the core 2 acting on the armature 3 is released, the valve 10 is held closed again by the elasticity of the valve spring 9, so that the nozzle 5a is closed again. Fuel injection from 5a is stopped.

Next, the operation of the spark plug will be described.
The high voltage from the ignition coil is high tension cord 6, screw stopper 7, set screw 8, pipe 6
1, the air is transmitted to the valve seat 5 via the valve spring 9 and the valve 10, and spark discharge is generated between the edge portion 5b of the valve seat 5 as a center electrode and the ground electrode 12 facing the edge seat 5b, thereby producing a mixture in the combustion chamber. Ignite. The yoke 17 and the housing sub-assy 2
0 is electrically connected to the cap 11 having the ground electrode 12 and corresponds to a ground side member.

According to the fuel injection device, the harness 43
By shielding the ignition noise of the ignition plug by the shield material 59 covering the, the noise level of the ignition noise on the harness 43 is lowered. Therefore, for example, it is possible to prevent the occurrence of leakage due to ignition noise from the electrical connection portion including the terminal 45 of the coil 42 and the harness 43 to the portion of the ground side member adjacent thereto, thereby eliminating malfunction due to the leakage. You can

In addition, in the case of the fuel injection device, a general insulated wire is often used with a current of 1 A or less, whereas a high current of 7 A at maximum and about 2 to 3 A on average flows. Therefore, the harness 43 that does not cover the shield material
If you try to cope with the above high current only with (insulated wire),
While the harness diameter becomes large and the device becomes large, there arises a problem that leakage from the insulating layer 43b also increases. However, by covering the harness 43 with the shield material 59, it is possible to cope with only the harness 43. It is possible to obtain an effect that the diameter can be reduced to reduce the size of the device and leakage from the insulating layer 43b can be reduced.

[0032]

According to the fuel injection device of the present invention, since the ignition noise of the ignition plug is shielded by the shield material covering the harness, the noise level of the ignition noise on the harness can be reduced, and thus the fuel can be reduced. It is possible to prevent the occurrence of leakage due to ignition noise of the fuel injection device in which the injection valve is integrally formed with the ignition plug, and to improve the malfunction due to the leakage.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a fuel injection device.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a partially enlarged view of FIG. 1;

FIG. 4 is a perspective view showing a harness.

FIG. 5 is a sectional view of a conventional fuel injection device.

FIG. 6 is a sectional view taken along line AA of FIG. 5;

FIG. 7 is a partially enlarged view of FIG. 5;

[Explanation of symbols]

 3 Armature 5 Valve seat 10 Valve 20 Housing sub-assembly (housing) 42 Coil 43 Harness 59 Shielding material

Claims (1)

[Claims] 1. A valve having an armature, a valve seat opened and closed by the valve, a fuel injection valve in which a coil for attracting the armature by energization and a harness electrically connected to the coil are incorporated in a housing, and the valve seat. A spark plug integrally formed with the fuel injection valve with the center electrode as a central electrode, wherein the harness is covered with a shield material made of a material having excellent conductivity.