JP2002519586A - Fuel injection valve - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention is a fuel injector having an axially movable valve needle (13), wherein the valve needle has at least one closure support (17) and a spherical And a valve closure (18). The closure support (17) houses the valve closure (18) in the downstream end region (46). This valve closure (18) cooperates with the valve seat (15) of the valve seat (14). Upstream of the valve seat (15), the valve seat (14) has alternating material areas (51) and material cutouts (52) over its entire circumference, while the closure support (17) has A material section (50) and an opening area (49) are alternately formed over the entire circumference in the end area (46). In this case, the material section (50) protrudes into the material cutout (52) and the material region (51) protrudes into the opening region (49). This fuel injection valve is particularly suitable for use in a fuel injection device of a spark ignition type internal combustion engine of a compressor compression type.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION The invention is based on a fuel injection valve of the type defined in the preamble of claim 1.

German Patent DE 38 31 196 A1 discloses a fuel injection valve in the form of an electromagnetically actuatable valve. In this known valve, the valve needle consists of a mover, a tubular coupling part and a spherical valve closure. The armature and the valve closure are connected to one another via a tubular connection. In this case, the connection part acts as a direct closure support, to which the valve closure is firmly connected by a welding seam. The coupling part has a number of flow openings, through which the fuel flows out of the inner through-opening and cooperates with the valve closure at the outside of the coupling part to or with the valve closure. It can flow up to the valve seat surface. In addition, the coupling tube has a longitudinal slit which extends over its entire length, through which fuel can flow very quickly from the inner through-opening due to its large-area hydraulic flow cross section. Most of the fuel to be injected already leaves the connection over the length of the connection, while a small amount of residual fuel leaves the connection directly for the first time at the sphere surface.

[0003] The fuel injector according to the invention having the features described in the characterizing part of claim 1 has the advantage that it can be manufactured particularly simply and inexpensively. It is particularly advantageous that the valve needle can be guided very accurately with little effort.

A spherical valve closure, which can be produced very precisely and easily in terms of roundness, serves for guiding below an axially movable valve needle, and the guide opening in the material area of the valve seat is a valve seat surface. In addition, it can be manufactured very accurately with little effort, so that an accurate guide of the valve needle can be obtained relatively easily (so-called high rotational accuracy of the ball as the valve closing body). The valve closure serves in this case for axial guidance of the valve needle and differs from the known closure support valve needle. In such known valve needles, the guide surface must be formed with great effort on the closure support.

The provision of a plurality of open areas in the region of the valve closure over the entire periphery of the end region of the closure support allows the best supply flow to the distribution area of the valve with little manufacturing effort. Is obtained. In contrast to the known valves, on the one hand the lateral openings and slits in the valve closure carrier can be omitted, and on the other hand the surfacing in the valve closure or the through-grooves in the valve seat can be omitted. According to the fuel injection valve of the present invention, such a later processing step can be omitted.

[0006] Advantageous further developments and refinements of the fuel injector according to claim 1 are possible by means of claim 2 and below.

It is advantageous if the material sections in the end regions of the closure support as well as the material regions of the valve seat are shaped to fit in and out of one another in at least one horizontal plane. is there. As a result, it is possible to secure the position of the closing body support and prevent the rotation of the closing body support in the valve seat body. maintain. Changes in jet geometry related to valve life are effectively eliminated. The through-flow region is advantageously obtained by chamfering the side surfaces and / or the material region of the material section in the end region.

[0008] It is particularly advantageous if the valve closure is fixed to the closure support by a non-materially connecting joining method, for example a press fit or a flange connection. It is particularly advantageous if the end region of the closure support projects downstream and beyond the spherical equator of the spherical valve closure.

[0009] Preferably, the closure support is formed as a cold pressed part.

Description of Embodiments Next, embodiments of the present invention will be described in detail with reference to the drawings.

The fuel injection valve according to the invention, which is partially schematically illustrated by way of example in FIG. 1, is an electromagnetically operable injection valve for a fuel injection system for a compression-mixed, spark-ignition internal combustion engine. It has a substantially tubular core 2 surrounded by an electromagnetic coil 1 and serving as an inner pole and partly as a fuel flow-through. This core 2 together with the upper disk-shaped cover element 3 enables a particularly compact construction of the fuel injector in the area of the electromagnetic coil 1. The electromagnetic coil 1 is surrounded by a ferromagnetic outer valve jacket 5 as an outer pole. This valve jacket 5 completely surrounds the electromagnetic coil 1 in the circumferential direction, and its upper end is rigidly connected to the cover element 3 by, for example, a welding seam 6. In order to close the electromagnetic circuit, the lower end of the valve jacket 5 is stepped and has a guide section 8. This guide section 8 axially surrounds the electromagnetic coil 1 in a manner analogous to the cover element 3 and forms a restriction of the electromagnetic coil 1 in a downward or downstream direction.

The guide section 8 of the valve jacket 5, the electromagnetic coil 1, and the cover element 3
An inner opening 11 or 58 is formed which extends concentrically with respect to the valve longitudinal axis 10, into which an elongate sleeve 12 extends, for example. The longitudinal opening 9 inside the ferrite sleeve 12 serves, in part, as a guide opening for a valve needle 13 which is movable axially along a longitudinal axis 10. The sleeve 12 is therefore dimensionally manufactured with respect to the inner diameter of the inner opening 9. This sleeve 12 ends, for example, in the region of the guide section 8 of the valve jacket 5 when viewed in the downstream direction. The sleeve 12 is rigidly connected to the guide section 8 by, for example, a welding seam 54. In addition to the axially movable valve needle 13, the stationary core 2 is also arranged in the longitudinal opening 9 of the sleeve 12. In addition to the guide of the valve needle 13 or the accommodation of the core 2, the sleeve 12 also has a sealing action,
A dry electromagnetic coil 1 is arranged in the injection valve. The sealing effect is also obtained by the disk-shaped cover element 3 completely covering the electromagnetic coil 1 on the upper side. Due to the opening 58 inside the cover element 3, the sleeve 12 and thus the core 2 can be formed in an extended manner, so that both components project out of the opening 58 and extend outward beyond the cover element 3.

Connected to the guide section 8 below the valve jacket 5 is a valve seat 14 formed according to the invention. The valve seat body 14 has an immovable valve seat surface 15 as a valve seat. The valve seat 14 is rigidly connected to the valve jacket 5 by a second welding seam 16 formed, for example, by a laser. The valve needle 13 is composed of a tube-shaped mover 17 and a spherical valve closure 18, which directly acts as a closure support. On the downstream end surface of the valve seat 14, a flat plate 20 with a flat injection hole is arranged, for example, in the recess 19. The rigid connection between the valve seat 14 and the plate 20 with injection holes is realized, for example, by a tight tubular welding seam 21. The tubular armature 17 is rigidly connected at its downstream end facing the plate with injection holes 20 to a spherical valve closure 18 by, for example, a flange.

The operation of the injection valve is performed electromagnetically in a known manner. For the axial movement of the valve needle 13 and thus for the opening or closing of the injection valve against the spring force of the return spring 25, the electromagnetic coil 1, the inner core 2 and the outer valve jacket 5 , And an electromagnetic circuit having the mover 17 is operating. The mover 17 is directed toward the core 2 at the end opposite to the valve closing body 18.

The spherical valve closure 18 cooperates with the valve seat surface 15 of the valve seat 14, which has a reduced diameter in the direction of flow, for example in the shape of a truncated cone. This valve seat surface 15 is formed for guiding the valve closing body 18 at the valve seat body 14 downstream of the guide opening 26 in the axial direction. The plate with spray holes 20 has at least one, for example four, spray openings 27 formed by erosion or stamping.

The depth of insertion of the core 2 in the injection valve is particularly important with respect to the travel of the valve needle 13. In this case, the end position of the valve needle 13 is defined by the contact of the valve closing body 18 with the valve seat surface 15 of the valve seat body 14 when the electromagnetic coil 1 is not excited, and the other end position of the valve needle 13 is set. The position is given by the contact of the mover 17 with the downstream end of the core 2 when the electromagnetic coil 1 is excited. The stroke is adjusted by sliding the core 2 in the sleeve 12 in the axial direction.
Is firmly connected to the sleeve 12 later depending on the desired position. In this case, laser welding is advantageous for forming the weld seam 22.

The valve longitudinal axis 1 of the core 2 which serves to supply fuel in the direction of the valve seat surface 15
In addition to the return spring 25, an adjusting sleeve 29 is inserted in the flow hole 28 extending concentrically with respect to zero. The adjusting sleeve 29 is used for adjusting the spring preload of the return spring 25 abutting the adjusting sleeve 29. This return spring 25
On the other side, is supported by a step portion 24 of a longitudinal hole 23 inside the mover 17. In this case, dynamic adjustment of the injection quantity is also performed by the adjusting sleeve 29.

Such an injection valve is characterized by a particularly compact construction. The components described so far form an independent pre-assembled component group. This component group can be described as a working part 30. The final adjusted and assembled working part 30 has, for example, an upper end face 32, beyond which, for example, two contact pins 33 project. The electric contact of the electromagnetic coil 1 is made via the electric contact pins 33 serving as the electric connection elements, and the electromagnetic coil 1 is excited.

A connection (not shown), which is characterized in particular by an electrical and hydraulic connection of the injection valve, can be connected to such a working part 30. The hydraulic connection between the connection (not shown) and the working part 30 is such that, with the injection valve fully assembled, the flow holes of the two components ensure an unimpeded flow of fuel. Obtained by being placed on each other. In this case, for example, the end face 32 of the working part 30 directly contacts and is firmly connected to the lower end face of the connection part. If the connecting part is assembled to the working part 30, the part of the core 2 and the sleeve 12 projecting beyond the end face 32 can protrude into the flow hole of the connecting part in order to increase the coupling stability. . In the connection area, for example, a sealing ring 36 is provided for a secure seal. This sealing ring 36 rests on the end face 32 of the cover element 3 and surrounds the sleeve 12. The contact pins 33, which serve as electrical connection members, make an electrical secure connection of the connection part with the corresponding electrical connection element when the valve is fully assembled.

The inner longitudinal hole 2 of the mover 17 formed by being stepped by the step portion 24
3 has a substantially annular cross section. The inner longitudinal bore 23 has a conical shoulder 45 at the lower end facing the valve closure 18. The shoulder 45 enlarges the longitudinal bore 23 in the downstream direction, which acts as a stop for the valve closure 18. Starting from the shoulder 45, the end region 46 of the armature 17 extends along the outer circumference of the spherical valve closure 18, in which case the shoulder 45 and the end region 46 are interrupted at least three times in the circumferential direction. Have been.

The spherical valve closure 18 has a spherical equator 48 that extends perpendicular to the valve longitudinal axis 10. The end region 46 extends up to or beyond the spherical equator 48 as viewed in the flow direction. In other words, in other words, at least the hemisphere, and thus the radius, of the spherical valve closure 18 is surrounded by a mover 17 as a closure support. End region 46 has a larger outer diameter than valve closure 18. A rigid connection between the closure support 17 and the valve closure 18, which is formed, for example, as a cold-pressed part, is obtained, for example, by a flange connection or a press or by a press fit and subsequent flange connection. In this case, in particular, the surrounding area downstream of the spherical equator 48 ensures a secure connection.

Beginning in the region of the shoulder 45, the end region 46 has at least three open regions 49 formed over its entire circumference. These three open areas 49 have axially extending components starting from the longitudinal holes 23 and are partially flowed by the fuel in the direction toward the valve seat surface 15. In this case, the fuel supplied to the longitudinal holes 23 flows substantially along the spherical surface. In the open area 49 in the end area 46 of the closure support 17, the same number of material areas 5 of the valve seat 14
1 has entered. This material region 51 extending upstream of the valve seat surface 15 has a precisely manufactured guide opening 26 for guiding the axially movable valve needle 13 in the region of the valve closure 18. A material notch 52 is provided between the material regions 51 over the peripheral surface of the valve seat body 14. In this material cutout 52, for example, three material sections 50 of the end region 46 of the closure support 17 interrupted by the open region 49 extend. A spherical valve closure 18 which can be manufactured very precisely and simply in terms of roundness serves for guiding below the valve needle 13, and the guide opening 26 in the material area 51 with the valve seat surface 15 with little effort. Since it can be manufactured very accurately, a very accurate guide of the valve needle 13 (so-called high rotational accuracy of the ball 18) can be obtained relatively easily. In the case of the known valve needles, on the other hand, the complicated guide surfaces of the closure support have to be formed in one piece.

FIGS. 2 and 3, which show cross-sectional views along the line II-II or III-III in FIG. 1, show the end of the closure support 17 which engages with each other alternately in the circumferential direction. The material section 50 of the region 46 and the material region 51 of the valve closure 14 are particularly clearly shown.
FIG. 2 shows that the material section 50 and the material area 51 of the end area 46 are in the plane of the spherical equator 48.
Are spaced from one another so that a slit-shaped through-flow area 55 is formed, through which fuel can flow in bundles towards the valve seat surface 15. I understand. The illustrated embodiment with three alternating material sections 50 and 51 in the end region 46, respectively, shows only one possible configuration. Similarly, for example, four, five,
First, six regions 46 and 51 can be formed.

[0024] III, which is located upstream of the sectional view of the valve seat body 14 along the line II-II in FIG.
The cross-sectional view along the line III is formed at the downstream end of the shoulder 45 so that the material section 50 and the material area 51 of the end region 46 fit in and out of each other exactly. . As a result, the closing body support 17 is securely fixed in the valve seat body 14 and prevented from rotating, so that the side surfaces of the material section 50 and / or the material area 51 of the end region 46 are obliquely chamfered. Formed downstream, through-flow area 5 following the downstream side
5 maintains a constant size and does not change in the circumferential direction. It is sufficient if the material section 50 of the closure support 17 fits precisely in the material cutout 52 of the valve seat 14, so that the desired anti-rotation already takes place. Variations in jet geometry with respect to valve life are thus effectively eliminated. In the region of the line III-III, the curvature of the spherical valve closure 18 results in an annular flow region 56 from which the axially expanding through-flow region 55 flows.

In addition to forming the closure support 17 as a cold-pressed part, it can also be configured as a lathe-processed part, a sintered part, or a MIM (Metal Injection Molding) part.

[Brief description of the drawings]

FIG. 1 is a view showing a fuel injection valve according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

[Explanation of symbols]

Reference Signs List 1 electromagnetic coil, 2 core, 3 cover element, 5 valve jacket, 6 welding seam, 8 guide section, 9 longitudinal hole, 10 valve longitudinal axis, 11 opening, 12 sleeve, 13 valve needle, 14 valve seat, 15 Valve seat surface, 16 weld seam, 17 mover, 18 valve closing body,
Reference Signs List 19 recess, 20 plate with injection hole, 21, 22 welding seam, 23 longitudinal hole, 24 step, 25 return spring, 26 guide opening, 27 injection opening, 28 flow hole, 29 adjusting sleeve, 30 working part, 32
End face, 33 Contact pin, 36 Seal ring, 45 Shoulder, 46
Edge area, 48 spherical equator, 49 open area, 50 material section, 51
Material area, 52 material notch, 54 weld seam, 55 through-flow area, 56
Flow area, 58 openings

Claims (11)

[Claims] 1. A fuel injection valve having a valve longitudinal axis, a core at least partially surrounded by an electromagnetic coil, and an axially movable valve needle, wherein the valve needle has at least one valve needle. A valve closure, which is rigidly connected to the closure support and cooperates with an immovable valve seat provided on the valve seat. Wherein the closure support has an inner longitudinal bore and a downstream end region, the valve seat (14) being upstream of the valve seat (15). And the material area (
51) and a material cut-out (52), in the end region () of the closure support (17).
46) are similarly formed so as to alternately have a material section (50) and an opening area (49) over the entire circumference, and the material section (50) enters the material cutout (52), and the material area (50). 51) protrudes into the opening area (49). 2. The valve seat (14) has at least three material zones (51).
) And a material cutout (52), wherein at least three material sections (50) and an open area (49) are respectively formed in the end region of the closure support (17). 2. The fuel injection valve according to 1. 3. The valve closure (18) has a spherical equator (48), and in the plane of the spherical equator, the material area (51) of the valve seat (14) is closed by a closure support (17). 3) The fuel injection valve according to claim 1 or 2, which is spaced apart from the material section (50). 4. A plane extending parallel to the spherical equator (48) is located upstream of the plane of the spherical equator (48), in which at least one of the closure supports (17) is located. The material section (50) is provided with at least one material notch (
The fuel injection valve according to claim 3, wherein the fuel injection valve is dimensionally fitted to (52). 5. The side of the material section (50) of the closure support (17) and / or the side of the material area (51) of the valve seat (14) are beveled, so that at least the spherical equator. 5. The fuel injection valve according to claim 3, wherein a flow-through area (55) is formed in the plane of (48) between the material area (51) and the material section (50). 6. The closure support (17) has a material section (46) in its end region (46).
6. The valve closure according to claim 3, wherein at 50) the material section surrounds the valve closure so that it extends downstream beyond the spherical equator of the valve closure. The fuel injection valve according to any one of the preceding claims. 7. The valve closure (18) is press-fitted into a longitudinal bore (23).
7. The fuel injection valve according to claim 1, wherein the fuel injection valve can be fixed to an end region (46) of the closure support (17). 8. The longitudinal closure (2) wherein the valve closure (18) is connected by a flange connection.
8. The fuel injection valve according to claim 1, wherein the fuel injection valve can be fixed in 3) to an end region (46) of the closure support (17). 9. The valve seat body according to claim 1, wherein the material region of the valve seat is a longitudinal axis.
Guide holes (26) for axial guidance of the valve closure (18) towards 0)
The fuel injection valve according to any one of claims 1 to 8, wherein the fuel injection valve is restricted. 10. The fuel injection valve according to claim 1, wherein the closure support (17) is formed as a mover. 11. The fuel injection valve according to claim 1, wherein the closure support (17) is a turned part or a cold pressed part.