EP1322859A1

EP1322859A1 - Fuel injection valve

Info

Publication number: EP1322859A1
Application number: EP01967032A
Authority: EP
Inventors: Guenter Dantes
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-09-19
Filing date: 2001-08-25
Publication date: 2003-07-02
Also published as: CZ20021735A3; JP2004509286A; WO2002025102A1; DE10046305A1; KR20020049055A; US20030066900A1

Abstract

The invention relates to a fuel injection valve (1), especially for directly injecting fuel into the combustion chamber of a mixture compression, spark ignition internal combustion engine, comprising a valve seat body (5) in which recesses (36) are provided upstream of a valve seat surface (6), and a guide disk (35) which interacts with the recesses (36) of the valve seat body (5) to produce closed swirl ducts (36a). Said swirl ducts (36a) open into a swirl chamber (37) with a tangential component and it is here that the incoming fuel obtains a speed component in the circumferential direction when the fuel injection valve (1)is open.

Description

ig: FUEL INJECTION VALVE

Fuel injector

State of the art

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

Fuel injection valves, which have a swirl-generating assembly, are known from DE 197 36 682 AI. They have a flat swirl disk in which recesses are made. In these recesses, which are closed to swirl ducts by a guide disk and by the valve seat body, the fuel flows toward a central opening, wherein it receives a peripheral speed through a tangential component of the recesses. In order to allow the fuel to flow into the swirl disk, the guide disk has a circumferential phase on the outside diameter.

Another fuel injection valve is known from DE 196 25 059 AI, in which the swirl is also generated upstream of the sealing seat. The fuel channels, via which the fuel is also metered, are introduced into the valve seat body, which also serves to guide the valve needle, by drilling so that the fuel radially in the direction is fed to the spray opening, the fuel channels having a tangential component and an axial component.

Furthermore, from DE 36 43 523 AI known that has an insert body above the sealing seat. Bores made in the insert body serve to generate swirl. After exiting the swirl channels, the fuel flows into a swirl chamber formed from the insert and the sealing surface. When the valve is open, due to the throttling of the flow in the swirl channels, there is a pressure drop at the insert, which is used to form a sealing surface pressure.

In the case of the fuel injection valves mentioned, a swirl is generated either through holes drilled in them, it being impossible to change the flow cross section along the flow path, or through the use of an additional component in the form of a swirl disk. The use of several components with manufacturing tolerances is particularly problematic since it leads to different results in the metering of the fuel and the formation of a spray cone. The use of many components is disadvantageous in terms of production technology.

Another disadvantage of the swirl disk from DE 197 36 682 AI are the burrs that arise when the disk is punched, as a result of which cost-intensive reworking is required to remove the burrs. Furthermore, the multi-part design of the swirl-generating assembly leads to an increased probability of errors in the assembly of the fuel injector, which must consist of several individual steps.

Another disadvantage of the fuel injector described in DE 36 43 523 AI is that a sealing surface pressure between the insert body and the valve seat surface is only in the open state of the Fuel injector exists because the formation of a flow to generate a corresponding force is the cause.

Advantages of the invention

The fuel injection valve according to the invention with the characterizing features of claim ^' 1 and the method according to the invention with the features of claim 10 have the advantage that the machining of the recesses takes place by machining a surface. The recesses are closed to form swirl channels by welding a cover. A change in the swirl channel geometry is thus possible in a simple manner, as is the change in the cross section within a channel. It is therefore easily possible to take into account the different customer requirements with regard to the metered fuel injection quantity and jet geometry. Despite the simple production of a large number of different variants, the use of the same parts remains constant.

Furthermore, after the component has been machined, the position and contour of the recesses can be checked before closed swirl channels are produced by fitting the cover. This results in a simple possibility to identify defective parts outside of the actual assembly process of the fuel injector. The number of reject fuel injectors is reduced.

Furthermore, caused by the welding of the guide pulley with the Ventilsitzkorper a compact assembly which can be treated in the further production process ^■ as one part. This makes it possible to grind the guide disc in the correct position together with the valve seat body. Positional tolerances between the valve seat surface and the central recess of the guide disk can thus be prevented. Through the Treatment of the assembly as a part also reduces the number of sources of error in the further assembly steps of the fuel injector.

The measures listed in the subclaims allow advantageous developments of the fuel injector specified in claim 1 and the method specified in claim 10.

The burr-free machining of the recesses means that there is no need for reworking, as is required, for example, when drilling fuel channels. By eliminating a processing step, the costs are reduced.

Through the use of machining processes in which there is no heat distortion on the valve seat body, the quality of the recesses is consistently high and a defined surface contour for forming a sealing surface with respect to the guide disk is ensured.

Another advantage is that the guide disc does not have to be guided radially through the nozzle body. The introduction of fuel channels into the guide disk for supplying fuel to the swirl channels can thus be dispensed with.

drawing

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

1 shows a schematic section through a fuel injector il according to the invention;

Fig. 2 shows a schematic section in section II of Fig. 1 by an embodiment of a fuel injector ils and Fig. 3 is a plan view of a valve seat body of a fuel injector according to the invention with recesses.

Description of the embodiment

Before an exemplary embodiment of a fuel injection valve 1 or a valve seat body 5 according to the invention is described in more detail with reference to FIGS. 2 and 3, for a better understanding of the invention, first of all with reference to FIG.

I the fuel injector 1 according to the invention will be briefly explained in an overall view with regard to its essential components.

The fuel injection valve 1 is in the form of a fuel injection valve for fuel injection systems of mixture-compressing, spark-ignited

Running internal combustion engines. The fuel injection valve 1 is particularly suitable for injecting fuel directly into a combustion chamber (not shown) of an internal combustion engine.

The fuel injector 1 consists of a nozzle body 2, in which a valve needle 3 is arranged.

The valve needle 3 is in operative connection with a

Ventilschlußkδrper 4, the one on one

Valve seat body 5 arranged valve seat surface 6 into one

Sealing seat interacts. In the exemplary embodiment, fuel injector 1 is an electromagnetically actuated valve that opens inwards

Fuel injector 1, which has a

Spray opening 7 has. The nozzle body 2 is through a

Seal 8 sealed against the outer pole 9 of a solenoid 10. The magnet coil 10 is in a coil housing

II encapsulated and wound on a coil support 12 which bears against an inner pole 13 of the magnet coil 10. The inner pole 13 and the outer pole 9 are separated from one another by a gap 26 and are supported on one Connecting component 29 from. The magnet coil 10 is excited via a line 19 by an electrical current that can be supplied via an electrical plug contact 17. The plug contact 17 is surrounded by a plastic sheath 18, which can be molded onto the inner pole 13.

The valve needle 3 is guided in a valve needle guide 14, which is disc-shaped. A paired adjusting disc 15 is used for stroke adjustment. An armature 20 is located on the other side of the adjusting disc 15. A restoring spring 23 is supported on the first flange 21, which in the present design of the fuel injector 1 is preloaded by a sleeve 24.

A second flange 31, which is also connected to the valve needle 3 via a weld 33, serves as the lower anchor stop. An elastic intermediate ring 32, which rests on the second flange 31, prevents bouncing when the fuel injector 1 closes.

In the valve needle guide 14, in the armature 20 and in the valve seat body 5, fuel channels 30a, 30b or recesses 36 run which guide the fuel, which is supplied via a central fuel supply 16 and filtered by a filter element 25, to the spray-discharge opening 7 in the valve seat body 5. The fuel injector 1 is sealed by a seal 28 against a distribution line, not shown.

In the idle state of the fuel injector 1, the armature 20 is acted on by the return spring 23 against the stroke direction via the first flange 21 on the valve needle 3 so that the valve closing body 4 is held in sealing contact with the valve seat surface 6. When the magnetic coil 10 is excited, it builds up a magnetic field, which moves the armature 20 against the spring force of the return spring 23 in the stroke direction, the stroke being predetermined by a working gap 27 located in the rest position between the inner pole 13 and the armature 20. The armature 20 takes the first flange 21, which is welded to the valve needle 3, and thus also the valve needle 3 in the lifting direction. The valve closing body 4, which is operatively connected to the valve needle 3, lifts off the valve seat surface 6 and the fuel reaching the spray opening 7 via the fuel channels 30a, 30b or recesses 36 is sprayed off.

If the coil current is switched off, the armature 20 drops from the inner pole 13 due to the pressure of the return spring 23 on the first flange 21 after the magnetic field has been sufficiently reduced, as a result of which the valve needle 3 moves counter to the stroke direction on, and the fuel injector 1 is closed.

In the fuel injection valve 1 designed according to the invention, a swirl of the fuel is generated by feeding the fuel into a swirl chamber 37, into which the recesses 36 serving as fuel guides open with a tangential ^component . For the reproducible metering of a defined amount of fuel, as shown in FIG. 2, a guide disk 35 is fixed on the top of the valve seat body 5, through which the recesses 36 in the valve seat body 5 are supplemented to form closed swirl channels 36a with a defined cross section.

The guide disc 35 is disc-shaped and has a recess 38 in which the valve closing body 4 is guided. The recess 38 of the guide disk 35 is tolerated relative to the diameter of the preferably spherical valve closing body 4 so that the formation of a bypass path between the valve closing body 4 and the guide disk 35 is prevented. The radial expansion the guide disk 35 is smaller than the inner diameter of the nozzle body 2. The fuel supplied via the fuel channels 30a, 30b flows through a gap 41 formed between the guide disk 35 and the nozzle body 2 into the recesses 36. The downstream underside 39 of the guide disk 35 has a shape corresponding to the upstream surface 40 of the valve seat body, so that the formation of a gap between the guide disk 35 and the valve seat body 5 is prevented.

The recesses 36 are made in the upstream surface 40 of the valve seat body 5, which can differ both in terms of their position with respect to the central axis 42 of the fuel injector 1 and in terms of their width and depth. The recesses 36, which are preferably straight or curved, open in the direction of flow into a swirl arm 37 located centrally in the valve seat body 5 and merging into the valve seat surface 6. The radial extension of the recesses 36 is greater than the radial extension of the guide disk 35. As shown in FIG. 3, the recesses 36 can also be guided radially out of the valve seat body 5 and open out at a bevel 44 of the valve seat body 5. At least one spray bore 7 is located downstream of the valve seat surface 6. The expansion of the recesses 36 in the radial direction outwards projects beyond the outer edge 43 of the guide disk 35 in order to facilitate the inflow of fuel into the swirl channels 36a.

Upstream of the valve seat surface 6 is the annular swirl chamber 37, which is formed by the valve closing body 4, the valve seat body 5 and the guide disk 35. The ^' small volume of the swirl chamber 37 when the fuel injection valve 1 is closed means that at the beginning of the injection process only the small one with fuel filled volume is sprayed without forming a swirl.

The recesses 36 can be made in accordance with the method according to the invention after the valve seat body 5 has hardened and can be done, for example, by electrochemical metalworking or eroding. To form the closed swirl channels 36a, the guide disc 35, e.g. by welding, attached to the valve seat 5. The assembly consisting of valve seat body 5 and guide disk 35 can be further processed together. A common grinding of recess 38 of the guide disk 35 and valve seat surface 6 thus prevents an offset of the central axes of the valve seat body 5 and the guide disk 35, as a result of which the wear of the fuel injection valve 1 is reduced.

Claims

Expectations

1. Fuel injector (1) for

Fuel injection systems of internal combustion engines with a valve seat body (5), which has a valve seat surface (6) which cooperates with a valve closing body (4) to form a sealing seat, a guide disk (35) with a central recess

(38), in which the valve closing body (4) is guided, and at least one swirl channel (36a) upstream of the

Valve seat surface (6) for generating a swirl of a fuel jet sprayed off by the fuel injection valve (1), characterized in that the valve seat body (5) has one or more recesses (36) on a surface (40) located upstream of the valve seat surface (6) are closed by the guide disk (35) to form one or more swirl channels (36a).

2. Fuel injection valve according to claim 1, characterized in that the swirl channels (36a) open into a swirl chamber (37) arranged above the valve seat surface (6).

3. Fuel injection valve according to claim 1 or 2, characterized in that that the swirl channels (36a) have a tangential component at their mouth into the swirl chamber (37).

4. Fuel injection valve according to one of claims 1 to 3, characterized in that the recesses (36) can be straight or curved.

5. Fuel injection valve according to one of claims 1 to 3, characterized in that the recesses (36) are curved.

6. Fuel injection valve according to one of claims 1 to 5, characterized in that the recesses (36) different widths and

Show depths.

7. Fuel injection valve according to one of claims T to

6, characterized in that the outside diameter of the guide disk (35) is smaller than the inside diameter of a nozzle body (2) in which the guide disk (35) is inserted.

8. Fuel injection valve according to one of claims 1 to 7, characterized in that the extent of the recesses (36) in the radial direction outwards ^{' is} greater than the outer edge (43) of the guide disc (35).

9. Fuel injection valve according to one of claims 1 to 6, characterized in that the recesses (36) in the radial direction on the outside

Open the chamfer (44) of the valve seat body (5).

10. Method for introducing swirl channels (36a) into a valve seat body (5) of a fuel injection valve (1) for fuel injection systems of internal combustion engines to generate a swirl of one of the fuel injection valve (1)

Fuel jet, the valve seat body (5) having a valve seat surface (6), which cooperates with a valve closing body (4) to form a sealing seat, and the fuel injection valve (1) has a guide disk (35) with a central recess (38) in which the Valve closing body (5) is guided with the following procedure steps:

- Making a predetermined number of recesses

(36) into an upstream surface (40) of the valve seat body (5),

- Arrange the guide disc (35) as a cover on the valve seat body (5) and

- Connect the guide disc (35) with the valve seat body (5).

11. The method according to claim 10, characterized in that the valve seat body (5) before the introduction of the

Ausne'hmungen (36) is hardened.

12. The method according to claim 10 or 11, characterized in that the recesses (36) are made contactless with electrochemical metal processing in the valve seat body (5).

13. The method according to claim 10 or 11, characterized in that the recesses (36) in the valve seat body (5) are eroded.

14. The method according to any one of claims 10 to 13, characterized in that after connecting the guide washer J35) is machined together with the valve seat body (5).