JP2002155834A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the flow controlling characteristics of a fuel injection valve related to the closing/opening time by forming an arbitrary characteristic curve by the disposition or the number of fuel passages. SOLUTION: This fuel injection valve 1 directly injecting fuel to a combustion chamber inside is such a type that an actuator 10 operating a valve needle 3 is provided therein, the valve needle 3 is provided with a valve closing body 4 in the end of the injection side, the valve closing body 4 comprises a seal seat coacting with a valve seat surface 6 formed in a valve seat body 5, and the fuel passages 35 are disposed in a valve needle guide 31 connected to the valve seat body 5 or integrally formed with the valve seat body 5. The fuel passages 35 are circumferentially disposed in the valve needle guide 31 into a lot of rows 34 and the number and their mutual disposition structures of the fuel passages 35 are so selected as to adjust the characteristic line expressing a dynamic fuel flow qdyn by the fuel injection valve 1 related to the valve needle stroke h.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for directly injecting fuel into a combustion chamber of an internal combustion engine. The fuel injection valve includes an actuator for operating a valve needle. A valve closing body at its side end, said valve closing body cooperating with a valve seat surface formed on the valve seat body to form a seal seat, which is connected to the valve seat body. Or a fuel passage arranged in a valve needle guide formed integrally with the valve seat.

[0002]

BACKGROUND OF THE INVENTION German Patent Publication No. 19625
No. 059 discloses a fuel injection valve having a number of fuel passages in a fuel flow path from a fuel inlet to an injection hole. In the cross section of these fuel passages, the amount of fuel injected at each predetermined time at a predetermined fuel pressure is defined. To affect the fuel distribution in the injected fuel spray, at least part of the fuel passage is:
The fuel flow supplied from the fuel passage is configured to be directly injected from the injection hole.

A disadvantage of the fuel injection valve known from the prior art is that the fuel passage is arranged in a plane perpendicular to the direction of fuel flow, ie the opening is connected to the valve seat support. In that it is arranged on a circle centered on the valve needle guide. As a result, the amount of fuel flowing through the fuel injection valve is not metered sufficiently accurately when the valve closure is lifted from the seal seat. In particular, the ratio of the maximum fuel injection amount to the minimum fuel injection amount is relatively small.

Furthermore, the number of holes is insufficient to obtain a sufficiently homogeneous fuel spray which satisfies the stoichiometric ratio requirement for complete combustion. This is additionally facilitated by the large diameter of the fuel passages.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art.

[0006]

According to an embodiment of the present invention which solves this problem, the fuel passages are arranged in the valve needle guide in a number of rows and circumferentially. And their mutual arrangement are selected in such a way that the characteristic line representing the dynamic fuel flow through the fuel injector in relation to the stroke of the valve needle is adjusted.

[0007]

According to the fuel injection valve having the features of the present invention, an arbitrary characteristic line can be formed by the arrangement of the fuel passages or the number thereof, as compared with the prior art.
This has the advantage that the metering characteristics of the fuel injector related to the opening and closing time are improved.

[0008] Advantageous refinements of the fuel injectors described in the main claim of the invention are possible by means of the dependent claims.

The hollow cylindrical configuration of the valve needle guide is as follows.
It can be easily manufactured and can be manufactured integrally with the valve seat support or can be fixed to the valve support.

By guiding the valve closing body in the valve needle guide, the metering characteristic can be controlled and improved, and the stroke of the valve needle can be stably affected.
This is because lateral displacement can be avoided. The valve closure rests very precisely on the sealing seat after the closing process.

The spacing in the rows of fuel passages affects the freely selectable injection kinetics and also the shapeable injection flow formation. This spacing can be influenced by intentionally providing fuel passages at discrete points in the valve needle guide.

By arranging the fuel passage having a tangentially extending portion relative to the central axis of the fuel injection valve, the fuel obtains a vortex for forming a good air-fuel mixture.

[0013]

Embodiments of the present invention will now be described with reference to the drawings.

Before describing in detail the embodiment of the fuel injection valve 1 according to the invention shown in FIGS. 2 to 7, in order to better understand the invention, the invention will first be described with reference to FIG. The fuel injection valve 1 already known, which is structurally the same as the embodiment of the present invention except for the features according to the present invention, will be briefly described with respect to its main components.

The fuel injection valve 1 is configured in the form of a fuel injection valve for a fuel injection device of an internal combustion engine of a mixture compression type spark ignition type. The fuel injector 1 is particularly suitable for directly injecting fuel into a combustion chamber of an internal combustion engine (not shown).

The fuel injection valve 1 comprises a nozzle body 2 in which a valve needle 3 is disposed. Valve needle 3
Is operatively connected to the valve closing body 4.
Forms a seal seat in cooperation with the valve seat surface 6 arranged on the valve seat body 5. In the illustrated embodiment, the fuel injection valve 1 has an injection hole 7 and is opened inward. The nozzle body 2 is fixed to the magnet coil 1 by the seal 8.
0 is sealed against the outer pole 9. Magnet coil 10
Is encapsulated in the coil casing 11,
The coil support 12 is wound around the coil support 12 and is in contact with the inner pole 13 of the magnet coil 10.
The inner pole 13 and the outer pole 9 are separated from each other by a gap 26 and supported by a coupling member 29. The magnet coil 10 is excited via a conductor 19 by a current which can be supplied via an electrical plug contact 17. The plug-in contact 17 is a plastic coating 1 that can be injected into the inner pole 13.
It is surrounded by eight.

The valve needle 3 is guided in a disc needle valve guide 14. For adjusting the stroke, a pair of adjusting disks 15 work. A mover 20 is provided on the other side of the adjustment disk 15. The armature 20 is connected to the valve needle 3 via a first flange 21 in a frictionally coupled manner (kraftschluessig), which is connected to the first flange 21 by a weld seam 22. A return spring 23 is supported on the first flange 21 and is preloaded by a sleeve 24 in the illustrated configuration of the fuel injector 1.

A second flange 31 connected to the valve needle 3 via a weld seam 33 serves as a lower armature stop. The elastic intermediate ring 32 mounted on the second flange 31 avoids an impact or a collision when the fuel injection valve 1 is closed.

Fuel passages 30a to 30c extend through the valve needle guide 14, the mover 20, and the valve seat 5, and these fuel passages 30a to 30c are supplied through a central fuel supply section 16 and are filtered. Element 25
The fuel filtered is guided to the injection hole 7. The fuel injection valve 1 is sealed by a seal 28 to a fuel path (not shown).

When the fuel injection valve 1 is at rest, the mover 2
0 is loaded in the direction opposite to the stroke direction by the return spring 23, and the valve closing body 4 is held in contact with the valve seat 6 in a sealed state. When the magnet coil 10 is excited, the magnet coil 10 forms a magnetic field that causes the mover 20 to move in the stroke direction against the return force of the return spring 23, in which case the stroke moves with the inner pole 12 in the rest position. Mover 20
And a working gap 27 between the two. The mover 20 similarly entrains the flange 21 welded to the valve needle 3 in the stroke direction. The valve closing body 4 operatively connected to the valve needle 3 is lifted from the valve seat surface 6 and the fuel guided to the injection hole 7 via the fuel passages 30a to 30c is injected.

When the coil current is cut off, the mover 20
After a sufficient disappearance of the magnetic field, it falls off the inner pole 13 by the pressure of the return spring 23, whereby the flange 21 operatively connected to the valve needle 3 moves in the direction opposite to the stroke direction. The valve needle 3 is thereby moved in the same direction, whereby the valve closure 4 is brought into contact with the valve seat 6 and the fuel injector 1 is closed.

FIG. 2 is a sectional view of a first embodiment of the fuel injection valve 1 according to the present invention.
2 is an enlarged view of the section indicated by II.

The fuel injection valve 1 according to the invention shown in FIG.
Has a valve needle guide 31, which is provided on the supply-side end face 32 of the valve seat 5.
Is formed. The valve needle guide 31 is in this case integrally formed with the valve seat 5 or, for example, by welding,
It is connected to the valve seat 5 by brazing or a similar method. The valve needle guide 31 is formed in a hollow cylindrical shape.

In the embodiment shown, the valve needle 3 has a spherical valve closure 4. The valve closing body 4 forms a seal seat together with a valve seat surface 6 formed on the valve seat body 5. The valve closure 4 is guided by a valve needle guide 31, wherein the valve closure 4 contacts an inner wall 38 of the valve needle guide 31 with a guideline 33. A plurality of rows of fuel passages 35 are arranged in the valve needle guide 31 between the guide line 33 and the seal seat, and these fuel passages 35 extend from the radial outside 36 to the radial inside 39 of the valve needle guide 31. Extending.

In this case, the fuel passage 35 extends perpendicular to the central axis 37 of the fuel injection valve 1 or is inclined at an angle α to the downstream with respect to the direction perpendicular to the central axis 37. May be. The latter angled arrangement is advantageous for flow.

As soon as the valve needle 3 is moved in the opposite direction to the fuel flow direction by operating the fuel injection valve 1,
The fuel passages 35 forming the row 34 are opened. Fuel flows from the radially outer side 36 of the valve needle guide 31 through the fuel passage 35 toward the seal seat.

With a suitable arrangement of the fuel passage 35, a characteristic line can be obtained which describes, adjusts or models the dynamic flow of fuel through the fuel injection valve in relation to the stroke of the valve needle 3. By appropriately producing the stroke of the valve needle 3, as much fuel as necessary within the range of the flow rate to be obtained flows through the fuel passage 35.

FIG. 3 shows the valve needle guide 31 of the first embodiment in the region of the fuel passage 35 along the line III-III of FIG.
FIG. 4 is a schematic sectional view taken along the line. In the illustrated embodiment, the fuel passages 35 of adjacent rows 34 are circumferentially offset from one another in order to obtain a mixture as homogeneous as possible. However, in order to achieve the required metering accuracy, the fuel passage 35
For example have a very small diameter of less than 100 μm, in particular less than or equal to 70 μm. The formation of such small-sized holes may be performed by, for example, laser processing.

The fuel passage 35 has a swirling flow (also called a vortex flow).
Has a tangential component with respect to the central axis 37 of the fuel injection valve 1 so that the cross section of the fuel passage 35 appears as an ellipse or an oval in FIG. In this case, the direction or direction of the tangential component of the fuel passage 35 may be the same in each row 34 with respect to the remaining rows 34.
Therefore, with the fuel injection valve 1 of the present invention of such an embodiment, a swirl flow formation with the accuracy of the fuel amount to be metered is achieved.

FIGS. 4 to 7 show, in the same section as FIG. 3, another embodiment of the different arrangement of the fuel passage 35 of the fuel injection valve 1 according to the invention, with a characteristic line obtained by this arrangement of the fuel passage 35. It is shown together with. With a uniform arrangement of the fuel passage 35, the flow rate increases relatively uniformly with the stroke of the valve needle 3 to achieve a constant saturation value, which is the open fuel injection valve. 1 represents a static flow through 1.

The embodiment shown in FIG.
Although having an arrangement similar to that of FIG. 3, the fuel passages 35 are not offset from one another in the circumferential direction,
They are arranged completely overlapping each other in a pattern similar to a grid. The characteristic lines of the embodiment shown in FIG. 3 and FIG.
This corresponds to the characteristic line shown schematically in FIG. 4B.

If the arrangement of the fuel passages 35 is changed, for example, so that the rows 34 do not entirely comprise the fuel passages 35 but have an interval 40, the characteristic line changes. For example, FIG.
A, as shown in FIG.
If the second fuel passage 35 is omitted in one row 34, that is, if every other fuel passage 35 is arranged, the characteristic line is deformed into an S-shape as shown in FIG. 5B. .
That is, at the beginning of the opening process, a small amount of fuel first flows through the fuel injection valve 1 and the valve closing body 4 opens the entire row 34 provided with the fuel passage 35 and has a steeper slope than in FIG. 4B. After an increase in the saturation value is reached.

The embodiment shown in FIG.
Are omitted, resulting in a longer circumferential spacing 40, in which case the number of rows 34 is further reduced. Thus, due to the significantly thinned out or sparse fuel passage 35, a much smaller amount of fuel flows at the beginning of the opening process, and the fuel amount increases to a saturated value significantly more rapidly with the opening of the remaining rows 34. A substantially step-like course is achieved as shown in FIG. 6B.

The embodiment shown in FIG. 7A also causes a sharp rise in the fuel flow, since the row 34 located near the seal seat is entirely provided with a fuel passage 35. Thus, the remaining rows 34 have only thinned fuel passages 35, or have large spacings 40, or the fuel passages 35 have been omitted altogether. The corresponding characteristic line is shown in FIG. 7B.

The characteristic lines shown in FIGS. 6B and 7B are particularly advantageous, in that the desired fuel quantity is metered in a short time, so that the flow rate quickly reaches the saturation quantity, and therefore the fuel injection valve 1 The opening and closing times can be well defined.

In all the embodiments, an extremely small
A minimum amount of fuel can be achieved, resulting in a minimum
Fuel quantity q that can be greatly injected_maxAnd minimum injectable fuel
Quantity q _minAnd the ratio q_max/ Q_minIs enhanced.

The present invention is not limited to the embodiment shown, but can be implemented, for example, for fuel injectors with piezoelectric and magnetostrictive actuators, or for any arrangement of fuel passages 35. .

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a fuel injection valve according to the prior art.

FIG. 2 is a sectional view showing a first embodiment of the fuel injection valve according to the present invention in a region II of FIG. 1;

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4A is a cross-sectional view taken along the line III-III of FIG. 2, illustrating a second embodiment of the fuel injection valve according to the present invention.

FIG. 4B is a view showing a characteristic line corresponding to the second embodiment shown in FIG. 4A.

FIG. 5A is a cross-sectional view taken along the line III-III of FIG. 2, illustrating a third embodiment of the fuel injection valve according to the present invention;

FIG. 5B is a diagram showing characteristic lines corresponding to the third embodiment shown in FIG. 5A.

FIG. 6A is a sectional view taken along the line III-III of FIG. 2, showing a fourth embodiment of the fuel injection valve according to the present invention;

FIG. 6B is a diagram showing a characteristic line corresponding to the fourth embodiment shown in FIG. 6A.

FIG. 7A is a sectional view taken along the line III-III of FIG. 2, showing a fifth embodiment of the fuel injection valve according to the present invention;

FIG. 7B is a diagram showing a characteristic line corresponding to the fifth embodiment shown in FIG. 7A.

[Explanation of symbols]

1 fuel injection valve, 2 nozzle body, 3 valve needle,
4 valve closing body, 5 valve seat, 6 valve seat surface, 7 injection hole, 8 seal, 9 outer pole, 10 magnet coil,
11 coil casing, 12 coil support,
13 inner electrode, 14 valve needle guide, 15 adjustment disk, 16 fuel supply section, 17 plug-in contact, 18
Plastic sheath, 19 conductor, 20 mover, 21 flange, 22 weld seam, 23 return spring, 24 sleeve, 25 filter element, 26 throttle gap, 27 working gap,
28 seal, 29 connecting member, 30a-30c
Fuel passage, 31 valve needle guide, 32 end face,
33 guidelines, 34 rows, 35 fuel passages,
36 Radial inward, 37 Center axis, 38 Inner wall, 39 Radial outward, 40 spacing

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F02M 61/04 F02M 61/04 BF (72) Inventor Detlef Novak Germany F term (reference) 3G066 AA01 AB02 AD07 BA36 BA51 BA54 CC15 CC20 CC41 CE22 DA08

Claims (11)

[Claims] 1. A fuel injection valve (1) for injecting fuel directly into a combustion chamber of an internal combustion engine, comprising an actuator (10) for operating a valve needle (3). The needle (3) has a valve closing body (4) at the injection-side end, the valve closing body (4) having a valve seat surface (6) formed on a valve seat body (5). The valve needle guide (3) which cooperates to form a seal seat and is connected to the valve seat (5) or formed integrally with the valve seat (5).
1) In the type having a fuel passage (35) arranged in the fuel passage (35), the fuel passage (35) is arranged in a plurality of rows (34) in the valve needle guide (31) in a circumferential direction. The number of these fuel passages (35) and their arrangement with respect to each other is characterized by a characteristic line indicating the dynamic fuel flow (q _dyn ) by the fuel injector (1) in relation to the stroke (h) of the valve needle. A fuel injector characterized by being selected to be adjusted. 2. The fuel injection valve according to claim 1, wherein the valve needle guide (31) is formed on an inflow end surface (32) of the valve seat body (5). 3. The fuel injection valve according to claim 2, wherein the valve needle guide (31) extends from the end face (32) of the valve seat (5) in a hollow cylindrical shape. 4. The valve closure (4) according to the guidelines (3).
In the area of 3), the inner wall (3) of the valve needle guide (31)
The fuel injection valve according to claim 3, wherein the fuel injection valve is formed so as to come into contact with (8). 5. A fuel injection valve (1) comprising: a fuel passage (35);
5. The fuel injection valve according to claim 1, wherein the fuel injection valve has a component tangential to the central axis (37) of the fuel injection valve. 6. The fuel injector according to claim 5, wherein the tangential components of the rows of fuel passages are arranged in the same direction. 7. The fuel cell of claim 1, wherein at least one of the rows of fuel passages has a spacing between the fuel passages. The fuel injection valve according to claim 1. 8. A row (34) having said spacing (40).
8. The fuel injection valve according to claim 7, wherein the valve is arranged in an injection-side portion of the valve needle guide (31). 9. The fuel injection valve according to claim 7, wherein the row (34) having the spacing (4) is arranged in a portion on the inflow side of the valve needle (31). 10. The fuel injection valve according to claim 7, wherein the intervals (40) are circumferentially offset from one another. 11. Spacing (40) of different rows (34).
10. The fuel injection valve according to any one of claims 7 to 9, wherein are defined differently in relation to number and / or circumferential length.