JP2004346817A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection valve of high performance by surely reducing the accumulation of deposit on a surface of an injection nozzle part. <P>SOLUTION: This fuel injection valve comprises a valve seat member 15 having the injection nozzle formed on one end of a hollow valve body 13, a valve element 12 for opening and closing the injection nozzle by being kept into contact with and separated from the valve seat member 15, and a swivel body 14 slidably supporting the valve element 12 in a state of surrounding the valve element 12 and applying the swivel to the fluid flowing into the injection nozzle, and the injection nozzle part of the valve seat member 15 is provided with a nozzle hole member 16 composed of a plurality of thin plates arranged in a multilayered state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine.
[0002]
[Prior art]
Conventionally, in a fuel injection valve for in-cylinder gasoline injection, in which gasoline fuel is directly injected from an injector into an engine cylinder, since the fuel injection valve faces a combustion chamber, heat generated by the fuel injection nozzle heated by combustion is reduced. The fuel is carbonized at the injection port due to a flame at the time of combustion, and a so-called deposit is generated.
It is generally known that in the process of deposit formation, the fuel is completely dried due to the high temperature, and grows as the residual solidifies.
Then, the deposits generated in the nozzle port accumulate on the surface of the nozzle port with the passage of time, which causes a problem when adjusting the amount of fuel and also causes a problem that the spray performance is impaired.
[0003]
In a conventional fuel injection valve, the injection port of the fuel injection valve is formed of a ceramic member, and when the inside of the cylinder is at a high temperature, the deposits are reduced by the burning-off effect of the ceramic member. Reference 1).
[0004]
In addition, a plurality of atomizers are attached to the injection port of the fuel injection valve, and slits are provided in each of the atomizers. There were also some attempts (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP-A-10-274134 (FIG. 1)
[Patent Document 2]
JP 2000-345944 A
[Problems to be solved by the invention]
Since the conventional fuel injection valve is configured as described above, there is a problem that the performance of the valve is impaired because the deposit generated at the injection port is not sufficiently removed.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a fuel injection valve capable of reliably reducing the accumulation of deposits on the surface of an injection port.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a fuel injection valve having a hollow valve body, a valve seat member provided at one end of the valve body and having an injection port, and opening and closing the injection port by separating from and coming into contact with the valve seat member. A valve body, and a revolving body that surrounds the valve body, slidably supports the valve body, and provides a swirl to the fluid flowing into the injection port. This is provided with a nozzle member in which a plurality of thin plates are arranged in multiple layers.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1 FIG.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side sectional view showing a fuel injection valve according to Embodiment 1 of the present invention. In the figure, the fuel injection valve 1 is composed of a solenoid device 2, a yoke 3, a valve holder 4, and a valve device 5. .
The solenoid device 2 has a bobbin 7 around which a coil 6 is wound, and a core 8 provided on the inner periphery of the bobbin 7, and the winding of the coil 6 is connected to a terminal 9.
The core 8 has a hollow cylindrical shape so that the inside thereof becomes a fuel passage. A compression spring 10 is installed in the hollow portion. An armature 11 is installed so as to face the tip of the core 8. I have.
[0010]
The valve device 5 includes a valve body 12, a hollow valve body 13, a swirler (swirl body) 14, a valve sheet member 15, and a plurality of thin plates arranged in a multilayer structure. It consists of.
After the valve body 13 is inserted into the inner diameter portion of the valve holder 4, the valve body 13 is connected to the valve body 12 at the welded portion 4 a, and the armature 11 is connected to the valve body 12 at the welded portion 11 a.
The swirler 14 is inserted or press-fitted into the inner diameter portion of the valve body 13, and further, the valve sheet member 15 and the injection port member 16 are press-fitted into the inner diameter portion of the valve body 13 and fixed at the welded portions 15 a and 16 a, respectively. Have been.
[0011]
FIG. 2 is an enlarged side sectional view showing the tip of the fuel injection valve 1, and fuel passages 14 a and 14 b are provided between the revolving unit 14 and the valve body 13.
FIG. 3 is a sectional view taken along line AA in FIG.
[0012]
Next, the operation will be described.
When an operation signal is sent from the microcomputer of the engine (not shown) to the drive circuit of the fuel injection valve 1, a current flows through the coil 6 of the fuel injection valve 1 and is composed of an armature 11, a core 8, a yoke 3, and a valve holder 4. When a magnetic flux is generated in the magnetic circuit to be performed, the armature 11 is attracted to the core 8 side, and the valve body 12 formed integrally with the armature 11 is separated from the valve seat member 15 to form a gap. The high-pressure fuel supplied from the supply pipe through the fuel filter 18 flows from the upstream portion of the swirler 14 installed inside the valve body 13 through the passages 14 a and 14 b between the swirler 14 and the valve body 13. After passing through the swirl passage from the outside and further swirling around the valve body 12 with the swirler 14, it passes through the valve seat surface 15a and the injection member inner surface 16a provided downstream of the valve seat surface 15a to the outside. Is Isa.
[0013]
Next, when an operation stop signal is sent from the microcomputer of the engine to the drive circuit of the fuel injection valve 1, the current to the coil 6 is cut off, the magnetic flux in the magnetic circuit decreases, and the valve body 12 is pushed in the valve closing direction. The gap between the valve body 12 and the valve seat surface 15a is closed by the compression spring 10 that is present, and fuel injection ends.
When the coil 6 is not energized, fuel is supplied from the upper part of the core 8 and the pressure inside the fuel injection valve 1 becomes 3 to 20 MPa.
[0014]
The spherical portion 12a located at the tip of the valve body 12 is in contact with the conical valve seat surface 15a, and the valve body 12 and the valve seat surface 15a are brought into contact with each other by the load by the compression spring 10 and the pressing load by the fuel pressure. At the contact portion, the fuel is sealed by a slight elastic deformation.
Next, when the coil 6 is energized and the valve body 12 is separated from the valve seat surface 15a, the valve body 12 is connected to the sliding portion 12b between the valve body 12 and the valve body 13 and between the valve body 12 and the swirler 14. The sliding operation is performed while being supported by the sliding portion 12c.
[0015]
In the present embodiment, since the injection port member 16 formed by stacking thin hollow cylindrical thin plate members in a multilayer at the fuel injection port downstream of the valve seat surface 15a is installed, the fuel injection port member remains downstream from the valve seat surface 15a at the end of fuel injection. The fuel that has been absorbed is absorbed by the overlapping surface 16b of the thin nozzle member 16 and exudes from the overlapping surface 16b until the next injection, so that the inner surface 16a of the nozzle member can always be kept wet with fuel.
This makes it possible to keep the inside of the nozzle at a moderately wet state without drying, to prevent deposits from adhering to the surface, to surely reduce deposit accumulation, and to maintain high performance.
[0016]
Further, by setting the surface roughness of the overlapping surface 16b to 2S or more, it is possible to stabilize the permeability of the fuel permeating between the thin plate members, and it is possible to provide a stable condition in which the deposit is difficult to deposit. .
Also, the surface of the thin plate member constituting the nozzle member 16 can be coated with titanium oxide having lipophilicity. By applying the titanium oxide coating in this manner, the wettability of the nozzle portion can be further improved, and the deposit can be deposited. Can be reduced.
[0017]
Embodiment 2 FIG.
FIG. 4 is an enlarged side sectional view showing a tip portion of a fuel injection valve according to Embodiment 2 of the present invention. In the present embodiment, an inner diameter of a hole forming an injection port in a plurality of thin plate members forming an injection port member 16 is shown. The difference is provided.
That is, in FIG. 4, constitute the spray port member 16 by overlapping and sheet inside diameter d ₂ of the thin plate and the nozzle hole inner diameter d ₁ of the injection port alternately. With this configuration, the surface area of the nozzle in the nozzle member 16 can be increased, and the heat generated by combustion can be efficiently radiated.
As described above, by lowering the temperature of the injection port, drying of the fuel can be suppressed, and an environment in which a deposit is not easily generated can be maintained.
[0018]
Embodiment 3 FIG.
FIG. 5 is an enlarged side sectional view showing a tip portion of a fuel injection valve according to Embodiment 3 of the present invention. In the present embodiment, a plurality of thin plate members constituting injection port member 16 have different thermal expansion rates. It was done.
That is, in FIG. 5, the injection port member is formed by alternately stacking thin plates having a coefficient of thermal expansion of A and thin plates having a coefficient of thermal expansion of B. With such a configuration, when receiving heat due to combustion, the change in the inner diameter forming the injection port of each thin plate member is different, and a step can be provided on the inner surface 16a of the injection member, and the deposit is formed on the inner surface 16a of the injection member. The deposited deposit can be torn, and the falling off of the deposit can be promoted.
Thereby, the accumulation of the deposit inside the injection port at the nozzle tip can be surely reduced.
[0019]
【The invention's effect】
According to the fuel injection valve according to claim 1 of the present invention, a hollow valve body, a valve seat member provided at one end of the valve body and having an injection port, and an injection port separated from and connected to the valve seat member. A valve body that opens and closes, and a revolving body that surrounds the valve body, slidably supports the valve body, and provides a swirl to the fluid flowing into the injection port. Since the injection port member in which a plurality of thin plates are arranged in multiple layers is provided, the accumulation of deposits on the surface of the injection port can be reliably reduced, and the performance of the fuel injection valve can be improved.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing a fuel injection valve according to Embodiment 1 of the present invention.
FIG. 2 is an enlarged side sectional view showing a tip portion of a fuel injection valve.
FIG. 3 is a sectional view taken along line AA in FIG. 2;
FIG. 4 is a side sectional view showing an injection port according to a second embodiment of the present invention.
FIG. 5 is a side sectional view showing an injection port according to a third embodiment of the present invention.
[Explanation of symbols]
12 valve body, 13 valve body, 14 revolving body, 15 valve seat member, 16 nozzle member.

Claims (5)

A hollow valve main body, a valve seat member provided at one end of the valve main body and having an injection port, a valve element which is separated from and connected to the valve seat member to open and close the injection port, and a valve surrounding the valve element. In a fuel injection valve provided with a revolving body that slidably supports a body and imparts a swirl to a fluid flowing into the injection port, a plurality of thin plates are arranged in multiple layers at the injection port portion of the valve seat member. A fuel injection valve provided with a selected injection port member. 2. The fuel injection valve according to claim 1, wherein the surface roughness of the overlapping surface of the thin plates is set to 2S or more. 3. The fuel injection valve according to claim 1, wherein the surface of the thin plate is coated with titanium oxide. The fuel injection valve according to any one of claims 1 to 3, wherein the injection port of the thin plate has a difference in inner diameter of the hole. The fuel injection valve according to any one of claims 1 to 4, wherein the thin plates have different coefficients of thermal expansion.

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