JP2017031952A - Fuel injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injector enabling atomization and capable of shortening penetration (hereinafter, low penetration) by causing fuel to stably collide with each other.SOLUTION: At a fuel injection hole (main injection hole) provided on a downstream side with respect to a sheet part, and on a downstream side of a fuel flow passage with respect to the main injection hole, provided is a portion having the following relationship of seat angles: θ1>θ2, and another fuel injection hole (sub injection hole) is provided at the above portion. fuel (main jet) injected from the main injection hole and fuel (sub jet) injected from the sub injection hole are caused to collide with each other.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a fuel injection device in an in-cylinder injection engine for automobiles using gasoline, particularly gasoline.

In recent years, automobile exhaust gas regulations have been strengthened, and automobile internal combustion engines are required to reduce particulate matter such as harmful exhaust gas HC (hydrocarbon) and soot. These emissions are generated when the fuel that collides with the wall surface of the cylinder, the intake valve or the like causes an unburned state or becomes locally rich. In order to suppress these, it is necessary to shorten the spray flow rate (penetration) so that the spray does not collide with the wall surface in the cylinder.
The following prior art discloses a technique in which fuels emitted from two or more fuel injection holes collide with each other to atomize.

Japanese Patent Application Laid-Open No. 09-042118

Patent Document 1 discloses a technique in which fuels emitted from two or more fuel injection holes (hereinafter referred to as injection holes) collide with each other to be atomized. However, in Patent Document 1, the fuel flow to the injection hole on the downstream side of the fuel flow path may be an acute angle among the fuels to be collided, and in this case, the fuel flow is separated in the injection hole. The fuel cannot be injected stably. Furthermore, since it is influenced by the pressure change of the air in the intake port, it is difficult to stably collide the fuel.
Accordingly, an object of the present invention is to provide a fuel injection valve that can stably collide fuels and shorten atomization and penetration (hereinafter referred to as low penetration).

In order to solve the above-described problem, a fuel injection hole (main injection hole) provided downstream of the seat portion and a portion where the seat angle θ1> θ2 is provided on the downstream side of the fuel flow channel from the main injection hole, Another fuel injection hole (sub-injection hole) is provided at the site, and fuel injected from the main injection hole (main injection flow) and fuel injected from the sub-injection hole (sub-injection flow) are caused to collide with each other.
In addition, a counterbore part is provided in the main nozzle hole so that the main jet and the sub-current flow collide with each other in the counterbore.

  According to the present invention, fuel can be caused to collide with each other at a flow rate and position aimed at, and as a result, low penetrability can be obtained stably.

Sectional drawing which shows the whole fuel injection valve by which this invention is implemented Enlarged view of fixed valve Enlarged view of θ2 Enlarged view of fixed valve Enlarged view of fixed valve Enlarged view of fixed valve

  The overall configuration of the embodiment will be described with reference to FIG. In the following, all the drawings are exaggerated for the purpose of explanation, and are different from actual dimensions.

  A high pressure pump (not shown) for supplying fuel under pressure and a pipe connecting the high pressure pump and the upper portion of the fixed core 107 are arranged on the upper portion of the fixed core 107 in FIG. Fuel is supplied in a pressurized state to the through hole 112 that is a passage. A seating surface for the spring 110 is provided on the upper end surface of the valve body 101.

  A regulator 111 is in contact with the upper end surface of the spring 110 opposite to the valve body 101. The adjuster 111 is fixed to the fixed core 107.

The valve body 101 is held by a guide member 103 and a mover guide 105 so as to reciprocate up and down.
In a closed state where the coil 108 is not energized, the valve body 101 is in contact with the fixed valve 102 provided at the tip of the nozzle 104 by the urging force of the spring 110, and the flow of fuel supplied from the high-pressure pump is reduced. It is shut off.

  The coil 108 is disposed on the outer peripheral portion of the fixed core 107, and a toroidal magnetic path indicated by an arrow 122 is formed through a movable core 106 that is integral with the housing 109, the nozzle 104, and the valve body 101.

  In addition, a plug for supplying power from the battery voltage is connected to the connector 114 formed at the tip of the terminal 113. The coil 108 is energized and de-energized through an end 113a of the terminal 113 by a controller (not shown).

  While the coil 108 is energized, a magnetic attractive force is generated between the movable core 106 and the fixed core 107 by the magnetic flux passing through the magnetic path 122. When the movable core 106 is sucked, it moves upward and moves until it collides with the lower end surface of the fixed core 107.

  As a result, the valve body 101 is separated from the fixed valve 102 and is opened, and the fuel supplied from the through hole 112 that is the fuel passage at the center of the fixed core 107 is injected into the combustion chamber from the injection hole 102a.

  When the power supply to the coil 108 is cut off, the magnetic flux in the magnetic path 122 disappears and the magnetic attractive force disappears. In this state, the spring force of the spring 110 that pushes the valve body 101 in the valve closing direction acts on the valve body 101. As a result, the valve body 101 is pushed back to the valve closing position in contact with the fixed valve 102.

  The fixed valve 102 includes a fixed valve side seat surface 102b formed in a substantially conical shape whose diameter is reduced toward the downstream side of the fuel flow path. On the other hand, the valve body 101 has a spherical valve opposite side seat surface 101a at the tip, and the annular seat portion 102h is formed when the valve body side seat surface 101a comes into contact with the seat surface 102b.

  Here, the features of the present embodiment will be described with reference to FIG.

FIG. 2 is an enlarged view of the fixed valve 102 portion.
The main injection hole 102c communicates the seat surface 102b and the combustion chamber side surface 102g and is formed in a cylindrical shape, and the fuel inlet portion is located downstream of the fuel passage with respect to the seat portion 102h.

As shown in FIG. 3 showing an enlarged view of the nozzle hole, when the angle of the seat surface 102b is θ1, θ1 is connected to the seat surface 102b and downstream of the fuel inlet of the main nozzle hole 102c. The angle θ2 portion 102j having a substantially conical surface shape having an angle different from that of the nozzle and having a diameter that decreases toward the downstream side of the fuel flow path is formed.
The θ1 and θ2 have a relationship of θ1> θ2, and have a sub-hole 102d formed in a cylindrical shape so as to communicate the θ2 portion 102j and the combustion chamber side surface 102g.
Further, the sub-jet flow ejected from the sub-bore hole 102d collides with the main jet flow ejected from the main nozzle hole 102c. That is, the axis of the main injection hole 102c and the axis of the sub injection hole 102d intersect inside the counterbore part.

By causing the main jet and the sub-jet to collide with each other, the flow velocity of the main jet can be reduced, so that a low penetration can be achieved.
Furthermore, according to the above-described configuration, the fuel flow angle θ3 into the sub injection hole 102d can be made obtuse, so that the fuel flowing on the seat surface 102b can easily flow into the sub injection hole 102d. it can.
As a result, the flow rate of the sub-jet stream injected from the sub-bore hole 102d is stabilized, and a desired flow rate can be made to collide with the main jet flow injected from the main injection hole 102c.

  On the other hand, in the case where the θ2 portion 102j is not provided and the sub-bore hole 102d is provided on the seat surface 102b, if the fuel flow angle θ3 into the sub-bore hole 102d is blunted, the main jet flow injected from the main nozzle hole 102c The collision position of the sub-jet injected from the sub-hole 102d becomes a collision at a position away from the fixed valve 102, and is greatly affected by the air flowing into the cylinder. It is difficult to make the secondary jet collide.

  The main injection holes 102c and the sub-bore holes 102d are formed in a cylindrical shape for ease of processing, but are substantially conical shapes whose diameters increase toward the downstream side of the fuel flow path using electric discharge machining or laser machining, and vice versa. In addition, it may have a substantially conical shape whose diameter decreases toward the downstream side of the fuel flow path, and the same effect can be obtained with shapes other than the cylindrical shape such as a quadrangular prism shape and an elliptical cylinder shape.

Here, the seat surface 102b is generally polished to ensure the sealing performance of the seat portion 102h, and the seat surface 102b and the seat surface 102b are disposed downstream of the main nozzle hole 102c as a tool escape portion for polishing. Concave portions 102e are formed which are connected and have a surface roughness greater than that of the sheet surface 102b.
The recess 102e has a substantially conical shape with a diameter that decreases toward the downstream side of the fuel flow path, and has a hemispherical tip.

  The θ2 portion 102j can be obtained by the concave portion 102e, and the sub-bore hole 102d communicates with the θ2 portion 102j of the concave portion 102e and the combustion chamber side surface 102g, and a sub-jet injected from the sub-bore hole 102d is a main injection. The main jet is ejected from the hole 102c.

  In FIG. 2, the main jet and the sub-jet are caused to collide outside the combustion chamber side surface 102g of the fixed valve 102. However, as shown in FIG. 4, the sub-jet may be caused to collide within the main injection hole 102c. .

  With this configuration, the fuel can collide with the main injection hole 102c, so that the main jet and the sub-jet can be reliably collided without being affected by the air in the cylinder.

  Next, the characteristics of the second embodiment will be described with reference to FIG.

FIG. 5 is an enlarged view of the fixed valve 102, and those assigned the same numbers as those in FIG. 2 have the same or equivalent functions as those in the first embodiment, and will not be described.
In the present embodiment, there is a cylindrical counterbore 102f provided on the line connecting the center of the fuel inlet portion and the fuel outlet portion of the main injection hole 102c so as to coincide with the axis, and the diameter of the counterbore portion 102f is Is larger than the diameter of the main injection hole 102c.

Similarly to the first embodiment, the sub-injection hole 102d has a substantially conical θ2 portion 102j having an angle smaller than the angle θ1 of the seat surface 102b downstream of the fuel inlet of the main injection hole 102c. And a cylindrical shape in which the fuel inlet is located on the surface of the θ2 portion 102j.
On the other hand, the fuel outlet of the secondary injection hole 102d is provided in the counterbore 102f, and the main jet and the secondary jet collide inside the counterbore 102f and inside the combustion chamber side surface 102g.

  According to the configuration described above, the main jet and the sub-jet collide with each other in the counterbore 102f, so that the main jet and the sub-jet can collide at a desired position without being affected by the air flowing into the cylinder.

  The main injection hole 102c, the sub-bore hole 102d, and the counterbore 102f have a cylindrical shape from the standpoint of ease of processing, but the diameter gradually increases toward the downstream side of the fuel flow path using electric discharge machining or laser machining. A conical shape, or a substantially conical shape whose diameter decreases as it goes downstream of the fuel flow path, may be obtained, and the same effect can be obtained with shapes other than a cylindrical shape such as a conical shape, a quadrangular prism shape, or an elliptical prism shape. Can do.

  Further, as shown in FIG. 6, the counterbore 102f is enlarged and the counterbore 102f and the recess 102e are directly communicated to form a crescent-shaped auxiliary fistula 102d so that the main jet and the subjet can collide with each other. good.

  In the first and second embodiments, it is desirable that the main injection hole diameter> the sub injection hole diameter.

  Thereby, by making a sub-injection hole small and reducing a sub-jet, the influence on the injection direction of the main jet by the collision of a sub-jet can be decreased.

DESCRIPTION OF SYMBOLS 101 ... Valve body 102 ... Fixed valve 102a ... Injection hole 102b ... Seat surface 102c ... Main injection hole 102d ... Sub injection hole 102e ... Recess 102f ... Counterbore part 102g ... Combustion chamber side surface 102h ... Sheet part 102j ... θ2 part 103 ... Guide Member 104 ... Nozzle 105 ... Movable element guide 106 ... Movable core 107 ... Fixed core 108 ... Coil 109 ... Housing 110 ... Spring 111 ... Adjuster 112 ... Through hole 113 ... Terminal end 114 ... Connector 115 ... Magnetic path

Claims (8)

A main injection hole provided downstream of the fuel flow path;
A portion that is θ2 having an angle smaller than the seat angle θ1 is provided on the downstream side of the fuel flow path from the main nozzle hole position, and the fuel inlet portion of the sub-injection hole is located at the site,
The fuel injection device, wherein the main injection hole and the sub injection hole are formed such that a sub jet injected from the sub injection hole collides with a main jet injected from the main injection hole. A seat surface on which the valve body is seated;
A downstream recess formed to be connected to the sheet surface and having a rougher surface roughness than the sheet surface;
A main injection hole provided downstream of the fuel flow path;
A sub-injection hole provided downstream of the main injection hole position and having a fuel inlet portion located in the downstream recess,
The fuel injection device, wherein the main injection hole and the sub injection hole are formed such that a sub jet injected from the sub injection hole collides with a main jet injected from the main injection hole. A main injection hole in which a seating surface on which the valve body is seated is provided downstream of the fuel flow path;
A sub-injection hole in which a fuel inlet is located downstream of the main injection hole position;
A fuel outlet portion of the sub injection hole is provided in a counterbore part, and the sub jet injected from the sub injection hole collides with the main jet injected from the main injection hole inside the counterbore part. A fuel injection device characterized by the above. 4. The fuel injection device according to claim 1, wherein the main injection hole diameter> the sub injection hole diameter.   3. The fuel injection device according to claim 1, wherein the main injection hole axis and the sub injection hole axis intersect inside the counterbore part. 4.   3. The fuel injection device according to claim 2, wherein the seat surface is polished.   3. The fuel injection device according to claim 2, wherein the downstream recess is formed by cutting.   3. The fuel injection device according to claim 2, wherein the downstream concave portion is an escape portion when machining with a tool for polishing the seat surface.

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