EP2616663A1

EP2616663A1 - Fuel injection valve

Info

Publication number: EP2616663A1
Application number: EP11736361.4A
Authority: EP
Inventors: Juergen Graner; Martin Maier; Takuya Mizobe; Bernd Rieg; Volker Sohm; Juergen Lander
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-09-16
Filing date: 2011-07-26
Publication date: 2013-07-24
Also published as: BR112013005956A2; JP5868407B2; CN103097713A; RU2013117023A; JP2013537277A; RU2572263C2; WO2012034755A1; CN103097713B; KR20130105832A; DE102010040916A1; US20140027545A1

Abstract

The invention relates to a fuel injection valve for fuel injection systems in internal combustion engines. The valve comprises an electromagnetic actuation element that includes a solenoid (1), a solid core (2), an outer magnetic circuit component (5), and a movable armature (17) for actuating a valve closing member (19) which cooperates with a valve seat surface (16) on a valve seat member (15). The valve is characterized by its extremely small outer dimensions. By optimizing the size of the electromagnetic circuit, the outer diameter D_M of the outer magnetic circuit component (5) can be kept to a maximum of 11 mm in the circumferential zone of the solenoid (1), which significantly increases the flexibility for mounting fuel injection valves having different lengths, said different lengths being perfectly possible as a result of the special modular design. As a fuel injection valve, the disclosed valve is particularly suitable for fuel injection systems in mixture-compressing internal combustion engines with externally supplied ignition.

Description

Description title

Fuel injector

State of the art

The invention relates to a fuel injection valve according to the preamble of the main claim.

From DE 38 25 134 AI a fuel injection valve is already known, which comprises an electromagnetic actuator with a magnetic coil, with an inner pole and with an outer magnetic circuit component and a movable valve closing body which cooperates with a valve seat body associated valve seat comprises. The injection valve is from a

Surround plastic encapsulation, wherein the plastic encapsulation extends above all in the axial direction serving as the inner pole connecting piece and the magnetic coil surrounding. At least in the area surrounding the magnetic coil magnetic field lines conductive ferromagnetic fillers are introduced in the plastic sheathing. The fillers surround the solenoid coil in the circumferential direction. The fillers are fine-grained parts of metals with soft magnetic properties. The magnetically embedded in the plastic small

Metal particles have a more or less globular shape and are magnetically isolated by themselves and thus have no metallic contact with each other, so that there is no effective magnetic field education. However, the positive aspect of a very high electrical resistance which arises in this case is also counteracted by an extremely high magnetic resistance which builds up reflected in a significant loss of power and thus determined in the overall balance negative functional properties.

It is further known from DE 103 32 348 AI a

Fuel injection valve, which is characterized by a relatively compact design. The magnetic circuit is formed in this valve by a magnetic coil, a fixed inner pole, a movable armature and an outer magnetic circuit component in the form of a magnet pot. For a slim and compact design of the valve several thin-walled valve sleeves are used, which serve both as a connecting piece and as a valve seat carrier and guide portion for the armature. The within the

Magnetic circuit extending thin-walled non-magnetic sleeve forms an air gap over which the magnetic field lines from the outer magnetic circuit component to the armature and inner pole pass. A fuel injector

Comparable design is shown again in the figure 1 and explained in more detail below for a better understanding of the invention.

In addition, from JP 2002-48031 A, a fuel injection valve is already known, which is also characterized by a thin-walled sleeve solution, wherein the deep-drawn valve sleeve extends over the entire length of the valve and in the magnetic circuit region has a magnetic separation point in which interrupted the otherwise martensitic structure is. This

Non-magnetic intermediate section is thus at the level of the working air gap between the armature and the inner pole and in relation to

Magnet coil arranged that the most effective magnetic circuit is created. Such a magnetic separation is also used to increase the DFR (dynamic flow ränge) over the known valves with conventional electromagnetic circuits. However, such constructions are in turn associated with considerable additional costs in the production. In addition, the introduction of such a magnetic separation with a leads

non-magnetic sleeve section to a different geometric design to valves without magnetic separation. Advantages of the invention

The fuel injection valve according to the invention with the characterizing features of claim 1 has the advantage of a particularly compact

Construction. The valve has an extremely small outside diameter, as it is known to experts in the field of intake manifold injection valves for

Internal combustion engines previously appeared to be impossible to produce with the highest functionality. Because of this very small dimensioning, it is possible to make the installation of the fuel injection valve much more flexible than previously conceivable. Thus, the fuel injection valves according to the invention in a variety of mounting holes of different vehicle manufacturers with numerous "extended tip" - variants, ie varying in length

Injector variants, without changing the valve needle length or the

Valve sleeve length due to the modular design valve are installed very compatible, without having to accept the resulting deterioration with respect DFR (dynamic flow ranks) and noise. The seated on the outer magnetic circuit component and sealing against the wall of the receiving bore on the suction pipe sealing ring is easily displaced.

The measures listed in the dependent claims advantageous refinements and improvements of claim 1

Fuel injection valve possible. Advantageously, the new geometry of the fuel injection valve has above all been set under the boundary conditions with respect to the quantities q _min , F _F and F _max . To the extremely small outside dimensions of the

Magnetic circuit with full functionality was able to realize

According to the invention, the outer diameter D _{A of} the armature is set to 4.0 mm <D _A <5.0 mm. From the small outer diameter D _{A of} the armature can result in a particularly light valve needle, so that it can result in the consequence in the operation of the fuel injection valve to significant noise reduction compared to the known intake manifold injection valves. It is particularly advantageous that with the inventive dimensioning of the fuel injection valve and the DFR (dynamic flow ranks) can be significantly increased compared to the conventional injectors DFR usual.

drawing

Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. Show it

Figure 1 is an electromagnetically actuated valve in the form of a

Fuel injection valve according to the prior art,

FIG. 2 shows a first embodiment of a valve according to the invention,

Figure 3 shows a second embodiment of a valve according to the invention and

Figure 4 shows a third embodiment of a valve according to the invention as

Particularly suitable "Extended Tip" version of the fuel injection valve shown in Figure 3. Description of the embodiments

In the figure 1 is exemplified an electromagnetically operable valve in the form of a fuel injection valve for fuel injection systems of mixture-compression, spark-ignited internal combustion engines according to the prior art for a better understanding of the invention.

The valve has a surrounded by a magnetic coil 1, serving as an inner pole and partially as a fuel flow largely tubular core 2. The magnetic coil 1 is of an outer, sleeve-shaped and stepped running, z. B. ferromagnetic valve jacket 5, which is an outer pole serving as outer magnetic circuit component, completely surrounded in the circumferential direction. The magnetic coil 1, the core 2 and the valve shell 5 together form an electrically excitable actuator. While embedded in a bobbin 3 magnetic coil 1 with a winding 4 surrounds a valve sleeve 6 from the outside, the core 2 in an inner, concentric with a valve longitudinal axis 10 extending opening 11 of

Valve sleeve 6 introduced. The valve sleeve 6 is elongated and thin-walled. The opening 11 is used u.a. as a guide opening for a valve needle 14 which is axially movable along the valve longitudinal axis 10. The valve sleeve 6 extends in the axial direction, e.g. over approximately half of the total axial extent of the fuel injection valve.

In addition to the core 2 and the valve needle 14, a valve seat body 15, which is attached to the valve sleeve 6, e.g. is fastened by means of a weld 8. The valve seat body 15 has a fixed

Valve seat surface 16 as a valve seat on. The valve needle 14 is formed for example by a tubular armature 17, a likewise tubular needle portion 18 and a spherical valve closing body 19, wherein the

Valve closure body 19 e.g. by means of a weld fixed to the

Needle portion 18 is connected. At the downstream end of the

Valve seat body 15 is a e.g. cup-shaped spray orifice plate 21 is arranged, the bent and circumferentially encircling retaining edge 20 is directed against the flow direction upwards. The solid connection of

Valve seat body 15 and spray disk 21 is z. B. realized by a circumferential tight weld. In the needle portion 18 of the valve needle 14, one or more transverse openings 22 are provided, so that the fuel flowing through the armature 17 in an inner longitudinal bore 23 to the outside and on the valve closing body 19, for. on flats 24 along to

Valve seat surface 16 can flow.

The actuation of the injection valve takes place in a known manner

electromagnetically. For axial movement of the valve needle 14 and thus to open against the spring force of an attacking on the valve needle 14

Return spring 25 and closing the injector serves the

electromagnetic circuit with the magnetic coil 1, the inner core 2, the outer valve shell 5 and the armature 17. The armature 17 is aligned with the valve closing body 19 facing away from the end of the core 2. Instead of the core 2, for example, also serving as an inner pole cover part, which closes the magnetic circuit may be provided.

The spherical valve closing body 19 cooperates with the valve seat surface 16 of the valve seat body 15, which tapers in the direction of the flow in the direction of flow and which is formed in the axial direction downstream of a guide opening in the valve seat body 15. The spray disk 21 has at least one, for example four by eroding, laser drilling or punching

molded spray openings 27.

Among other things, the insertion depth of the core 2 in the injection valve is crucial for the stroke of the valve needle 14. The one end position of the valve needle 14 is fixed at non-energized magnetic coil 1 by the system of the valve closing body 19 on the valve seat surface 16 of the valve seat body 15, while the other End position of the valve needle 14 results in energized solenoid coil 1 by the system of the armature 17 at the downstream end of the core. The stroke is adjusted by an axial displacement of the core 2, which is subsequently connected according to the desired position fixed to the valve sleeve 6.

In a concentric with the valve longitudinal axis 10 extending flow bore 28 of the core 2, which serves to supply the fuel in the direction of the valve seat surface 16, except for the return spring 25, an adjustment in the form of an adjusting sleeve 29 is inserted. The adjusting sleeve 29 is used to adjust the spring preload applied to the adjusting sleeve 29 return spring 25, which in turn is supported with its opposite side to the valve needle 14 in the region of the armature 17, wherein an adjustment of the dynamic Abspritzmenge with the adjusting sleeve 29. A fuel filter 32 is disposed above the adjusting sleeve 29 in the valve sleeve 6.

The inlet end of the valve is made of a metal

Fuel inlet 41 formed by a stabilizing this, protective and surrounding plastic extrusion coating 42 is surrounded. A concentric to the valve longitudinal axis 10 extending flow bore 43 of a pipe 44 of the fuel inlet nozzle 41 serves as a fuel inlet. The plastic extrusion coating 42 is sprayed, for example, in such a way that the

Plastic immediately parts of the valve sleeve 6 and the valve shell 5 surrounds. A secure seal is achieved, for example via a labyrinth seal 46 on the circumference of the valve shell 5. For Kunststoffumspritzung 42 includes a mitangespritzter electrical connector 56. Figure 2 shows a first embodiment of an inventive

Fuel injector. From Figures 1 and 2 or 3 not immediately apparent due to not the same scale are the

Fuel injector according to the invention by a very slim design, a very small outer diameter and an overall extremely small geometric design. The dimensioning according to the invention will be explained in more detail below. In the present example, the valve sleeve 6 is designed to extend over the entire valve length. The outer magnetic circuit component 5 is cup-shaped and can also be referred to as magnet pot. The magnetic circuit component 5 has a jacket section 60 and a bottom section 61. At the upstream end of the

Sheath portion 60 of the outer magnetic circuit member 5 is e.g. a

Labyrinth seal 46 is provided, with which the seal against the magnetic circuit component 5 surrounding Kunststoffumspritzung 42 is achieved. The bottom portion 61 of the magnetic circuit component 5 is characterized for example by a fold 62, so that a double position of the folded

Magnetic circuit component 5 is present below the magnetic coil 1. With a support ring 64 which is applied to the valve sleeve 6, on the one hand, the folded bottom portion 61 of the magnetic circuit component 5 is held in a defined position. On the other hand, the lower end of an annular groove 65 is defined with the support ring 64, in which a sealing ring 66 is inserted. The upper end of the annular groove 65 is defined by a lower edge of the plastic extrusion coating 42. By a suitable dimensioning of the magnetic circuit, the outer diameter D _{M of} the outer magnetic circuit component 5 in the peripheral region of the magnetic coil first only <= 11 mm. In the present embodiment of the magnetic circuit member 5, since the skirt portion 60 is cylindrical, the magnetic circuit member 5 does not have a larger outer diameter than 11 mm at any point. On the

Outer circumference of the outer magnetic circuit component 5 is in the range of

Jacket section 60 applied directly to the sealing ring 66, so that the fuel injector even with its radially outwardly pushed onto the magnetic circuit sealing ring 66 is still in receiving holes on the intake manifold with an inner diameter of 14 mm can be introduced. The sealing ring 66 may in the peripheral region of the outer magnetic circuit component 5 at its largest

Outer diameter may be provided.

In order to be able to realize the smallest possible outside diameter of the magnetic circuit, the internal components, such as the core 2 serving as inner pole 2 and the armature 17, must be dimensioned correspondingly above all very small. When re-sizing the magnetic circuit was therefore as a minimum necessary size for the inner diameter of the core

2 and anchor 17 set by 2 mm. The inner diameter of the two components core 2 and armature 17 define the internal flow area, wherein it has been found that with an inner diameter of 2 mm, the setting of the dynamic injection quantity is still possible with an internal return spring 25, without the tolerance of the inner diameter of the return spring 25 affects the static flow rate. In the design of the magnetic circuit different sizes and parameters play an essential role. So it is optimal to minimize the minimum discharge q _min as possible. However, it should be noted again that the spring force F _F > 3 N must be maintained in order to guarantee the current and future required tightness of <1.0 mm ³ / min. A spring force of F _F >

3 N corresponds in the present design with a sealing diameter of d = 2.8 mm of the static magnetic force at a voltage U _min of F _sm > 5.5 N.

The maximum magnetic force F _max is for the design of a

Fuel injection valve with electromagnetic drive also an essential Size. If F _{max is} too small, for example <10 N, this may cause a so-called "closed stuck." This means that the maximum magnetic force Fmax is too small to overcome the hydraulic adhesive force between the valve closing body 19 and the valve seat surface 16 In that case, that would

Fuel injector despite energization can not open.

The new geometry of the fuel injector has therefore above all been determined under the boundary conditions with respect to the quantities q _min , F _F and F _max . According to the invention was found in the optimization of the geometry of the magnetic circuit that the outer diameter D _{A of} the armature 17 is a significant size. The optimum outer diameter of the armature 17 is 4.0 mm <D _A <5.0 mm. From this, the dimensions of the outer magnetic circuit component 5 can be derived, wherein an outer diameter D _{M of} the magnetic circuit component 5 of a maximum of 11 mm, the full functionality of the magnetic circuit even with respect to known injectors significantly increased DFR (dynamic flow ranks) guaranteed. In the embodiment according to FIG. 2 with a continuous thin-walled valve sleeve 6, the optimized dimensioning provides a wall thickness t for the valve sleeve 6 at least in the area of the working air gap, ie in the lower core region and in the upper anchor region, of 0.15 <t <0.35 mm ,

The previously made geometry and dimensioning considerations also apply analogously to a fuel injection valve in another embodiment, as shown in FIG. This fuel injection valve according to FIG. 3

differs essentially from that according to Figure 2 in the region of the valve sleeve 6, the core 2 and the outer magnetic circuit component 5. Die

Valve sleeve 6 is shorter here and extends from the discharge end of the valve only into the region of the solenoid coil 1. Upstream of the movable valve needle 14 with the armature 17, the valve sleeve 6 is fixedly connected to the tubular core 2. This means that a stroke adjustment via a displacement of the core 2 within the valve sleeve 6 is not possible here. At its axially opposite end, the core 2 is in turn connected to a tube 44 of the tube concentric to the valve longitudinal axis 10 Fuel inlet neck 41 attached. In this embodiment, so far over the entire valve length continuous thin-walled valve sleeve 6 is present. In the embodiment of the outer magnetic circuit component 5 has been dispensed with a bottom portion, so that the component 5 has a tubular shape. This is possible because the valve sleeve 6 has a radially outwardly standing flange-like collar 68, on the outer circumference of which the magnetic circuit component 5 rests and is fastened to it, for example, by means of a circumferential weld seam. The support ring 64 is designed as a flat disc-shaped flange. FIG. 4 shows a third embodiment of a valve according to the invention as a particularly suitable "Extended Tip" version of that shown in FIG

Fuel injection valve shown. With reference to this figure is again the already mentioned and particularly advantageous possibility of very flexible installation of the fuel injection valve according to the invention in a

Receiving bore on a suction pipe using standard components already known from other injectors (valve needle, armature, valve sleeve) are explained. Many vehicle or engine manufacturers design the receiving bores for the fuel injection valves in the intake manifold injection in the intake module in a stepped version. Here, the channel of the intake pipe facing end portions of the

Injector receiving holes usually have a diameter of about 11 mm. These stepped versions of the mounting holes have prevailed for several reasons. For one, this is for the

Fuel injection valve, a "penetration protection" available, that is

Possibility of slipping of the fuel injection valve in the

Intake pipe is excluded. On the other hand, the stepped receiving bores reduce or avoid tilting of the fuel injection valves. Furthermore, there is an improved flow guidance in the intake manifold for the intake air, since the only approximately 11 mm diameter end portion of the receiving bore due to a smaller circulation area allows a longer homogeneous flow of air in the bore area.

In addition, it is necessary for design and stability reasons for the suction module, that around the mounting holes a minimum size of them surrounding webs is present on the intake manifold, which at a size of

End portions of the receiving bore of about 11 mm diameter is given much sooner. To incorporate suitable fuel injectors into such pre-described staged fuel injector mounting bores, it has heretofore been common to have "extended tip" variants of the fuel injectors

provide. For this purpose, the fuel injection valves had to be redesigned by all necessary for the forward displacement of the Abspritzpunktes components of the fuel injection valve were extended.

Advantageously, with the invention described a

Fuel injection valve before that waiving an extension of components anyway without functional disadvantages has a very deep Abspritzpunkt by the fuel injector with its entire discharge side functional group incl. Magnetic circuit in a stepped end of the

Recording hole can disappear. As can be seen from FIG. 4, the sealing ring 66 can be variably mounted on the magnetic circuit component 5 in its axial position. In the present embodiment of the magnetic circuit member 5, since the skirt portion 60 is cylindrical, the magnetic circuit member 5 does not have a larger outer diameter than 11 mm at any point. On the

Jacket section 60 applied directly to the sealing ring 66, wherein the fuel injection valve even to the support ring 64 on the sealing ring 66 in stepped end portions of the mounting holes on the suction pipe with a

Inner diameter of 11 mm can be introduced.

Claims

claims

1. Fuel injection valve for fuel injection systems of

Internal combustion engine, having a valve longitudinal axis (10), with an excitable actuator in the form of an electromagnetic circuit with a magnetic coil (1), an inner pole (2), an outer magnetic circuit component (5) and a

movable armature (17) for actuating a valve-closing body (19) which cooperates with a valve-seat surface (16) provided on a valve-seat body (15),

characterized,

that the outer diameter of the outer magnetic circuit component (5) in

Peripheral region of the magnetic coil (1) D _M <= 11 mm.

2. Fuel injection valve according to claim 1,

characterized,

in that the magnetic circuit component (5) is cylindrical with a jacket section (60) and in that the magnetic circuit component (5) at no point has a larger outer diameter than 11 mm.

3. Fuel injection valve according to claim 1 or 2,

characterized,

in that a sealing ring (66) is applied directly on the outer circumference of the outer magnetic circuit component (5).

4. Fuel injection valve according to claim 3,

characterized,

the sealing ring (66) is provided in the peripheral region of the outer magnetic circuit component (5) at its largest outer diameter.

5. Fuel injection valve according to claim 3 or 4, characterized,

that the fuel injection valve with its radially outwardly pushed on the magnetic circuit sealing ring (66) in receiving bores on a suction pipe with an inner diameter of 14 mm or in end portions of the

Receiving bores with an inner diameter of 11 mm can be introduced.

6. Fuel injection valve according to one of the preceding claims, characterized in that

the following applies to the outer diameter D _{A of} the armature (17):

4.0 mm <D _A <5.0 mm.

7. Fuel injection valve according to one of the preceding claims, characterized in that

that a thin-walled valve sleeve (6) is provided, which extends at least in the region of the electromagnetic circuit.

8. Fuel injection valve according to claim 7,

characterized,

that a wall thickness t of the valve sleeve (6) at least in the region of

Working air gap, ie in the lower core area and in the upper anchor area, 0.15 <t <0.35 mm.

9. Fuel injection valve according to claim 7 or 8,

characterized,

in that the thin-walled valve sleeve (6) extends over the entire axial length of the fuel injection valve.

10. Fuel injection valve according to one of the preceding claims, characterized in that

in that the outer magnetic circuit component (5) is cup-shaped and, to that extent, has a jacket section (60) and a bottom section (61).

11. Fuel injection valve according to claim 10, characterized,

the bottom section (61) is double-layered by a fold (62).

12. Fuel injection valve according to one of claims 1 to 8,

characterized,

the core (2) is connected at its downstream end to the valve sleeve (6).

13. Fuel injection valve according to claim 12,

characterized,

the valve sleeve (6) has a radially outwardly projecting flange-like collar (68) on whose outer circumference the magnetic circuit component (5) bears and is fastened to it.