EP0786049A1

EP0786049A1 - Fuel injection valve

Info

Publication number: EP0786049A1
Application number: EP96928321A
Authority: EP
Inventors: Waldemar Hans; Thomas Betzel; Peter ASSLÄNDER; Reinhold BRÜCKNER; Uwe Grytz; Christian Preussner; Stefan Lauter; Rainer Bottler; Robert Schmidt-Hebbel
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1995-08-10
Filing date: 1996-07-24
Publication date: 1997-07-30
Anticipated expiration: 2016-07-24
Also published as: CN1158153A; EP0786049B1; CN1066243C; DE19529375A1; DE59606717D1; US5904299A; WO1997006365A1; JPH10507509A; KR970706454A

Abstract

In known fuel injection valves, gas is supplied in an adapter through gas supply channels oriented towards the fuel in a central opening. These adapters are made of a single piece, so that no variable gas dosage is possible and machining the gas supply channels is made more difficult. The new adapter body (50) for a fuel injection valve (1), however, is made of several pieces, namely a base body (51) and at least one calibrating sleeve (52). Gas is supplied and dosed through the calibrating sleeve (52), whereas the base body (51) serves only for sealing and fixing purposes. Size-accurate calibrating sleeves (52) may be easily and economically machined. This design allows a great diversity of embodiments to be obtained in a simple manner. This fuel injection valve is particularly useful for fuel injection systems of spark-ignited, high compression ratio internal combustion engines.

Description

Fuel injector

State of the art

The invention relates to a fuel injector according to the preamble of the main claim. A fuel injection valve for injecting a fuel-gas mixture from US Pat. No. 4,982,716 is already known, in which an adapter is provided at the downstream end of a nozzle body, into which a gas can be introduced. The gas is supplied via two feed channels or holes which run obliquely to the longitudinal axis of the valve and which open into an inner spray region of the adapter such that the gas hits the fuel either upstream or downstream of a centrally arranged impact surface. The impact surface divides the fuel into two spray holes. The supply channels for the gas have a constant diameter and circular cross section over their length. In order to guarantee an exact metering of the gas, the metering cross section must be made with high dimensional accuracy. Since the entire adapter must be handled when introducing the feed channels, this processing step is comparatively cost-intensive. In addition, the size of the feed channels once introduced can no longer be varied.

These statements also apply to fuel injectors, as they e.g. B. from DE-OS 41 03 918 and US-PS 5,035,358 are known. Here too, supply channels for a gas are provided in an attachment body on the valve, which always have a constant diameter and circular cross section. The feed channels are direct again introduced in the front body, so that the entire front body must be handled when processing.

In known injection valves with gas supply in an attachment body, it is the case that the functions

Air supply or measurement and the attachment to the injection valve are solved together, so that an optimum of both functions is hardly possible due to the integration.

Advantages of the invention

The fuel injector according to the invention with the characterizing features of the main claim, in contrast, has the advantage of greater freedom of design and inexpensive to manufacture due to a functional separation in the front body of the

Fuel injection valve, which is used for fuel processing by means of a gas provided and metered in it. In addition, there is an advantageous functional separation of gas supply and metering compared to the sealing of the fuel injector to an intake line and the attachment of the attachment body to the fuel injector, so that each function is better guaranteed.

It is particularly advantageous to design the attachment body in such a way that at least one calibration sleeve for metering the gas can be installed in a base body. During the basic body of the sealing of the fuel injector to an intake line and the attachment of the attachment body to the actual one

Serves fuel injector, the calibration sleeves are mainly responsible for the gas supply and metering.

The measures listed in the dependent claims are advantageous further developments and improvements in Main claim specified fuel injector possible.

A beam splitter can be provided in the base body in an advantageous manner

Fuel injector maintained or reinforced.

A large variety of variants can be very easily achieved in that different ones for different specific applications in the same basic body

Calibration sleeves can be used. In this sense, there is a modular system.

The materials of the base body and the calibration sleeves can advantageously differ from one another. When selecting the material for the base body, individual requirement criteria only play a very minor role, such as: B. temperature sensitivity.

drawing

Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description. 1 shows a partially illustrated fuel injector with an attachment body according to the invention, FIG. 2 shows a second example of an attachment body, FIG. 3 shows a third example of an attachment body, FIG. 4 shows a section of an attachment body with a stepped calibration sleeve, FIG. 5 shows a section of an attachment body with a partially conical one Calibration sleeve, Figure 6 shows a calibration sleeve with beads on its circumference and Figure 7 shows a calibration sleeve with prongs on its circumference. Description of the exemplary embodiments

In FIG. 1, a valve in the form of a fuel injection valve for fuel injection systems of mixture-compressing spark-ignition internal combustion engines is partially shown as a first exemplary embodiment. Together with an attachment body according to the invention, the fuel injection valve serves to inject a fuel-gas mixture into an intake pipe or directly into a combustion chamber of the internal combustion engine.

The fuel injection valve 1, which can be actuated electromagnetically, for example, extends concentrically along a longitudinal axis 2 of the valve. As part of a valve housing, the fuel injection valve 1 has a nozzle body 5 which extends at the downstream end. In the nozzle body 5, a stepped longitudinal bore 7 is formed, which runs concentrically to the longitudinal valve axis 2 and in which a z. B. needle-shaped valve closing part 10 is arranged. The valve closing part 10 has, for example, two guide sections 11, 12 which, together with a guide region 13 of the wall of the longitudinal bore 7 of the nozzle body 5, serve to guide the valve closing part 10. The longitudinal bore 7 of the nozzle body 5 has at its downstream end a fixed valve seat 15 tapering in the direction of the fuel flow, which together with a sealing section 17 of the valve closing part 10 tapering in the fuel flow direction forms a seat valve.

At its end facing away from the sealing section 17, the valve closing part 10 is connected to a tubular armature 20 which has a magnetic core 22 partially surrounding the armature 20 in the axial direction and a tubular core 23 opposite the armature 20 in the direction away from the fixed valve seat 15 Fuel injector 1 interacts. At the end of the valve closing part 10 connected to the armature 20 there is a return spring 25 with one end, which strives to move the valve closing part 10 in the direction of the fixed valve seat 15. With its other end, the return spring 25 is supported on a z. B. non-magnetic adjusting sleeve 27.

On an end face 30 of the nozzle body 5 of the fuel injector 1 facing away from the core 23, there is an injection orifice disk 32 which is fixedly connected to the nozzle body 5, for example, by means of a weld seam produced by means of laser welding. The spray orifice plate 32 has, for example, four spray openings 33 through which the fuel flowing past the valve seat 15 when the valve closing part 10 is lifted off is sprayed off.

For the supply and metering of a gas, which is used for the improved treatment and atomization of the fuel, is at the downstream end of the

Fuel injector 1, an attachment body 50 is provided, for example made of plastic. As a gas z. B. the suction branched off by a bypass in front of a throttle valve in an intake manifold of the internal combustion engine, air conveyed by an additional fan, but also recirculated

Exhaust gas from the internal combustion engine or a mixture of air and exhaust gas can be used. The use of recirculated exhaust gas enables a reduction in the pollutant emissions of the internal combustion engine. The supply of the gas to the attachment body 50 is not shown in more detail in FIG. 1.

The attachment body 50 is formed by at least one base body 51 and by at least one calibration sleeve 52 according to the invention, which can be inserted or inserted into the base body 51. The base body 51 is, for. B. an injection molded part made of plastic and has a full axial passage 55 for a fluid that is very variable in design can be designed according to the valve design. In the upstream part of the z. B. centrally around the valve longitudinal axis 2 provided passage 55 projects the downstream end of the nozzle body 5, so that the base body 51 surrounds the nozzle body 5 partially radially. The base body 51 also extends in the axial direction downstream of the downstream end of the nozzle body 5 with the spray openings 33.

The base body 51 has z. B. an outer contour that does not run with a constant diameter over its axial extent. Rather, the base body 51 has, for example, an upper section 57 at the level of the downstream end of the nozzle body 5, the outer contour of which extends inclined to the longitudinal axis 2 of the valve, the diameter of the base body 51 increasing in the downstream direction. At the upper section 57, a lower, downstream section 58 of the base body 51 follows, on the circumference of which, for. B. a circumferential annular groove 59 is provided. A sealing ring 60 can be inserted into the annular groove 59 for sealing between the circumference of the injection valve or the attachment body 50 and a valve receptacle (not shown), for example the intake line of the internal combustion engine.

The entire attachment body 50 is on the injection valve, especially on the nozzle body 5 z. B. by engaging a circumferentially formed in the upper section 57 on the inner passage 55, extending radially from the inner wall in the direction of the longitudinal valve axis 2 and having a small height, bead 62 in a circumferential groove 64 on the nozzle body 5 so that no risk of loosening the Connection due to vibrations or temperature effects. A suitable selection of the bead 62 and the groove 64 can also ensure complete security against rotation. By means of e.g. B. interlocking and interacting depressions or elevations on the bead 62 and in the groove 64 the anti-rotation is achieved. In addition, other types of connection of the attachment body 50 on the nozzle body 5 instead of snapping or snapping are conceivable, such as. B. gluing or shrinking, which, however, result in permanent connections. Furthermore, one

Protection against rotation of the attachment body 50 is possible by means of a knurl or surfaces in the groove base of the groove 64 on the nozzle body 5.

In the first exemplary embodiment shown in FIG. 1, the passage 55 is divided into three axially successive sections. A first upstream passage section 66 is designed in diameter so that the downstream end of the nozzle body 5 can be received in it. In the area of the bulge 62, the passage section 66 has a slightly smaller opening width than over its remaining length. With a smaller diameter than that of the

Passage section 66 connects a second central, cylindrical passage section 67 to the passage section 66, so that a step in

Attachment body 50 is formed, on which the nozzle body 5 z. B. with its spray plate 32 and can no longer reach into the passage section 67. In the downstream direction, the middle passage section 67 is immediately followed by a third lower one

Passage section 68, the z. B. is characterized by two openings 69. If, for example, a dual-jet fuel injector 1 for injecting fuel in the direction of two intake valves is to be achieved or maintained, it is expedient to provide a beam splitter 70 in the lower passage section 68 of the base body 51, which extends between the two openings 69.

The beam splitter 70 can be the most varied

Have embodiments that are selected depending on the desired beam angle and images can. In FIG. 1, the web-like beam splitter 70 is shown by way of example with a pointed cutting edge, which is directed towards the spraying orifice plate 32, while, starting from the cutting edge, the beam splitter 70 widens in cross section in the downstream direction, so that it has a triangular cross section. The double radiation, the z. B. is already generated by the spray openings 33 of the spray plate 32, but can be impaired by an intermediate gas supply, is retained by the beam splitter 70 or is amplified. A beam splitter 70 in the base body 51 can of course also be dispensed with if the fuel does not have to have multiple beams.

The gas supply to the fuel passing through the passage 55 takes place via one or more calibration sleeves 52. The calibration sleeves 52 are inserted into passage openings 72 of the base body 51, which, for. B. obliquely to the longitudinal valve axis 2, starting from the inclined upper section 57 of the outer contour through the base body 51 through to the walls of the openings 69 of the lower passage section 68. The outer diameter of the calibration sleeves 52 and the diameter of the through openings 72 are selected so that there is an interference fit and thus the calibration sleeves 52 cannot slip. The hollow cylindrical calibration sleeves 52 have a continuous inner longitudinal opening 73 through which the gas is supplied. The inner longitudinal openings 73 are made or calibrated very precisely in their cross section and determine or measure the one flowing into the passage 55

Amount of gas too. At its upper end, the calibration sleeve 52 z. B. on a flat collar 75, which has a larger diameter than the through opening 72 and which bears against the upper portion 57 of the outer contour of the base body 51. In this embodiment, the

Longitudinal openings 73 of the calibration sleeves 52 have a constant diameter over their entire length. The function of the gas metering is thus placed in a separate component, namely in the longitudinal opening 73 of the calibration sleeve 52, which can be manufactured separately from the base body 51. In known injection valves with a gas enclosure, one-piece attachment bodies with gas supply channels are provided, which can only be manufactured very cost-intensively due to the required high dimensional accuracy of the cross-section to be metered. In the attachment body 50 according to the invention, the

Multiple parts (basic body 51 / calibration sleeves 52) achieve a functional separation. The calibration sleeves 52 can now be produced as small parts in large quantities much more cost-effectively using simple machining processes. The materials of the base body 51 and the calibration sleeves 52 can thus also advantageously differ from one another. As already mentioned, the base body 51 can be, for example, an injection molded part made of plastic; however, other materials are also conceivable. When selecting the material for the base body 51, individual requirement criteria only play a very minor role, such as. B. the temperature sensitivity. This results in greater freedom of design for the attachment body 50. In addition, it is so very easily possible to equip existing base bodies 51 with different calibration sleeves 52, so that a large variety of variants can be achieved without having to make major changes to the attachment body 50 itself.

All other figures concentrate on the design of the attachment body 50 or the calibration sleeves 52 and show the fuel injector 1 only in a simplified and schematic manner with the downstream end of the nozzle body 5. The calibration sleeves 52 of the exemplary embodiment in FIG. 2 differ from those in FIG that their inner longitudinal openings 73 along the opening width change the flow. This can e.g. B., as shown, take place via a step 77 or continuously continuously in the form of conical openings. The lower passage section 68 is e.g. B. is designed as a complete conical opening section widening in the flow direction, ie it has no beam splitter. In addition, the outer contour of the base body 51 is present in a somewhat modified form, for example in that the base body 51 is not completely beveled in its upper section 57, but instead has an upper cylindrical end section 78.

FIG. 3 shows an attachment body 50 with a base body 51, which has a perpendicular outer contour, that is to say parallel to the valve longitudinal axis 2, in the area of the upper section 57. The upper section 57 thus has a cylindrical shape and surrounds the downstream end of the nozzle body 5, which is only indicated schematically, just as in the exemplary embodiments already described. Due to the vertical outer contour of section 57, the calibration sleeves 52 extend z. B. horizontally, at right angles to the longitudinal axis 2 of the valve up to the inner passage 55. With their collars 75 they in turn rest against the outer wall of the upper section 57. The metering inner longitudinal openings 73 of the

Calibration sleeves 52 now open z. B. in the central, cylindrical passage section 67 of the passage 55, since the section 57 extends axially in the downstream direction as far as the middle passage section 67.

Figures 4 to 7 show further embodiments of calibration sleeves 52, the z. B. are arranged as in the embodiment shown in FIG. 3, ie extend horizontally from the outer section 57 to the central passage section 67. In FIG. 4 An example of a calibration sleeve 52 can be seen, which neither extends to the outer wall of section 57 nor to the wall of passage section 67, but ends just before on both sides. The passage opening 72 in the base body 51 for fitting the calibration sleeve 52 is, for. B. stepped, since a shoulder 79 is provided in the base body 51, through which the diameter of the passage opening 72 is reduced towards the valve longitudinal axis 2. With a corresponding design of the calibration sleeve 52 with a step on its outer circumference, it lies

Calibration sleeve 52 on the paragraph 79 to size. Instead of a step 77 for changing the opening width of the inner longitudinal opening 73, a conical taper 80 of the longitudinal opening 73 can also be provided, by means of which the gas throughput can be brought to a desired value.

The calibration sleeve 52 shown in FIG. 5 has an inner longitudinal opening 73 with a step 77 that reduces the opening width. In contrast to this, the passage opening 72 now has a conical taper 81, which in turn also specifies the outer contour of the calibration sleeve 52. The calibration sleeve 52 thus likewise has a conical outer region which is designed in accordance with the taper of the through opening 72. Towards the middle passage section 67, the passage opening 72 is e.g. B. formed with a diameter that corresponds to the diameter of the calibration sleeve 52 at the end of the conical taper.

FIGS. 6 and 7 show two calibration sleeves 52 which are distinguished by additional security measures. The calibration sleeves 52 pressed into the through-openings 72 can e.g. B. have on their outer circumference anti-slip devices such as rounded beads 84 or pointed prongs 85, which claw into the material of the base body 51 and thus represent a safeguard against the calibration sleeves 52 from slipping. In addition to the exemplary embodiments shown, further possible variations are conceivable, which will be briefly mentioned below. So z. B. the number of calibration sleeves 52 per attachment body 50 variable.

Usually one to six calibration sleeves 52 will probably be used. The calibration sleeves 52 may or may not be directly aligned with the spray openings 33 of the spray orifice plate 32 of the fuel injection valve 1. Except for the circular shown

Cross-section of the longitudinal openings 73 are also conceivable square, rectangular (slit), oval and other cross-sectional shapes. To secure against slipping of the calibration sleeves 52 in the through openings 72, the calibration sleeve 52 can, for. B. a collar 75 (Figures 1, 2, 3, 6, 7), a shoulder 79 (Figure 4) or a cone (Figure 5). If the pressing is sufficiently large, a variant without protection is also conceivable.

Claims

claims

1. Fuel injection valve for fuel injection systems for injecting a fuel-gas mixture in internal combustion engines, with a longitudinal valve axis, with a movable valve closing part, with a nozzle body, which has a valve seat interacting with the valve closing part, with at least one spray opening downstream of the valve seat, with one at the downstream End of the injection valve arranged front body, which has at least one means for gas supply and from which ultimately a fuel-gas mixture emerges, characterized in that the front body (50) of a base body (51) with an inner, in the axial direction complete passage ( 55) and at least one calibration sleeve (52) inserted into the base body (51), which is a continuous one

Longitudinal opening (73), through which gas is supplied and metered to the fuel injected into the passage (55).

2. Brennεtoffeinεpritzventil according to claim 1, characterized in that both the base body (51) and the at least one calibration sleeve (52) εind made of a plastic.

3. Fuel injection valve according to claim 1, characterized in that the at least one calibration sleeve (52) in the base body (51) is arranged so that it extends obliquely to the longitudinal axis of the valve (2).

4. Fuel injection valve according to claim 1, characterized in that the at least one calibration sleeve (52) in the base body (51) is arranged so that it runs horizontally, that is at right angles to the longitudinal axis of the valve (2).

5. Fuel injection valve according to one of the preceding claims, characterized in that the at least one calibration sleeve (52) in a through opening (72) of the base body (51) is introduced, which from the outer

Contour of the base body (51) extends up to the inner passage (55).

6. Fuel injection valve according to claim 5, characterized in that the calibration sleeve (52) provided in the passage opening (72) has at one end a flat collar (75) which bears on the outer contour of the base body (51).

7. Fuel injection valve according to claim 1, characterized in that the longitudinal opening (73) of the calibration sleeve (52) has a cross-sectional reduction in the flow direction of the gas, which is abrupt or continuous.

8. Fuel injection valve according to claim 5 or 6, characterized in that the calibration sleeve (52) extends over the full length of the through opening (72) in the base body (51).

9. Fuel injection valve according to claim 1, characterized in that a calibration sleeve (52) anti-slip devices (84, 85) are provided on the outer circumference of the least.

10. Fuel injection valve according to claim 1, characterized in that a beam splitter (70) is arranged in the passage (55) in the base body (51).