EP1273791A2 - Fuel injection valve for internal combustion engines - Google Patents

Abstract

A sliding valve body (64) has a second throttle opening (122) that discharges into a control area (62) and is sealed when the valve body comes next to a control device (72) and linked to a high-pressure space (20) when the valve body is lifted off. A control opening (82) and a first throttle opening (74) are displaced in relation to each other and interconnected by a throughway (76) limited by the control device and the sliding valve body.

Description

The present invention relates to a fuel injector for intermittent fuel injection in the combustion chamber of an internal combustion engine with the Features in the preamble of claim 1 and 13th

A fuel injector that features in the The preamble of claim 1 is in EP-A-0 675,281 and US-A-5,655,716. A control piston a nozzle needle protrudes into a control chamber at the upper end. A valve is arranged above this control piston, whose valve body runs coaxially to the control piston is laterally sealed in the valve housing. The The valve body protrudes with one, the control piston facing end, in the control chamber and with the the other end into one with a drain line via Control valve communicating additional chamber, which with the Control chamber through a through the valve body leading throttle bore is connected. This Throttle bore and thus the control chamber are one cross the other throttle bore in the valve body continuously the high pressure part of the fuel injector connected. One connected to the high pressure part around the Annular chamber running around valve body is above from one interacting with the valve body Valve seat limited. In the closed position of the nozzle needle the control piston is at a distance from the valve body, while in the open position of the nozzle needle Control piston on the lower face of the valve body strikes. Immediately after the control valve is closed takes place on the one hand through the transverse throttle bore Pressure build-up initially in the additional chamber, as a result the valve body moves against the control piston and thus an independent opening of the valve seat causes. An additional flows through this opening Inflow of the high pressure control medium into the Auxiliary chamber, which removes the nozzle needle from the valve body at increased speed to the closed position brought. After the closing position is reached the valve body is due to the pressure build-up in the Control chamber and back with spring force support moved upwards until it touches the valve seat.

The older EP-A-1 118 765 discloses one Fuel injection valve for internal combustion engines, whose needle-shaped injection valve member one has stepped control piston, which in a as Closing spring for the compression spring acting on the injection valve supporting sleeve engages. On the side facing away from the spring The sleeve is supported on a control body which fixed in a housing of the fuel injector is arranged. The sleeve has one through a shoulder formed extension on. In this extension is a arranged sleeve-shaped valve body, being between this and the sleeve has a gap. The The valve body works with its axial faces on the one hand with the shoulder and on the other hand with the Control body together, the length of the valve body is slightly smaller than the distance between the Shoulder and the control body so that the valve body back and forth in the axial direction by a small stroke can move. The smaller part of the diameter The spool is in a tight sliding fit in the valve body guided. Between the one facing away from the control body End of the valve body and the larger in diameter Part of the control piston is an annular space, which with one arranged inside the housing and over a high-pressure inlet with fuel-fed high-pressure space connected via a gap between the corresponding part of the sleeve and the diameter major part of the control piston is formed. A control room is on the one hand from the control piston, on the other hand from Control body and on the circumferential side of the sleeve-shaped valve body limited. A constriction that acts as a throttle having control passage runs through the control body from the front end delimiting the control room to opposite end face that has a low pressure space limited. The control passage is electromagnetic operated pilot valve with the low pressure chamber connectable or detachable at this.

A fuel injector that features in The preamble of claim 12 is in EP-A-0 426 205. With this fuel injector is the control room on the circumference of the housing of the fuel injector and seen in the axial direction on the one hand on a double-acting control piston of the Injector member and on the other hand by one Intermediate valve body that between itself and the housing leaves an annular gap free, and the annular gap limiting control body, which is arranged fixed to the housing, limited. Between the control piston and the intermediate valve body a compression spring is arranged. In axial Direction runs through the intermediate valve body a stepped bore that throttles. An extension of this hole runs through the control body through another hole, which by means of a electromagnetically operated pilot valve with a Low pressure space can be connected and separated from it. In this axial bore in the Control body opens another hole with a circumferential annular groove in the control body in connection stands, which in turn with the high pressure inlet of the Fuel injector is connected. Of this The ring groove runs several holes to the intermediate valve body facing end face of the control body. These holes are in contact with the control body Intermediate valve body closed by this.

It is an object of the present invention to create generic fuel injection valve, quickly for another injection process ready.

This task is accomplished through a fuel injector solved, which has the features of claim 1.

In addition to the simplicity, the fuel injector according to the invention is at the same time extremely compact. It needs little space especially in diameter. The properties the fuel injector can through the injection valve according to the invention the possibilities in a simple way Requirements can be interpreted adapted. In particular is the fuel injector according to the invention in each case again very quickly for another injection process ready. By the available Damping options can have a very long life be achieved. Further advantages result from the following description of the embodiments.

Preferred forms of training are in the dependent Claims specified.

Claim 12 relates to a further particularly simple one Form of training of a fuel injector.

Fig. 1

im Längsschnitt ein Brennstoffeinspritzventil;

Fig. 2

ebenfalls im Längsschnitt und bezüglich Fig. 1 vergrössert einen Teil des dort gezeigten Einspritzventils mit der Steuervorrichtung und der Elektromagnetanordnung;

Fig. 3a

einen Querschnitt durch das Einspritzventil der in Fig. 2 mit III-III bezeichnet ist;

Fig. 3b

in perspektivischer Darstellung Teile zur Abstützung der Schliessfeder des Brennstoffeinspritzventils;

Fig. 4

im Längsschnitt und bezüglich Fig. 1 und 2 vergrössert einen Teil des dort gezeigten Brennstoffeinspritzventils mit der Steuervorrichtung;

Fig. 5

in gleicher Darstellung wie Fig. 4 eine erste Ausbildungsform der erfindungsgemässen Steuervorrichtung;

Fig. 6

in gleicher Darstellung wie Fig. 4 und 5 eine zweite Ausbildungsform der erfindungsgemäss ausgebildeten Steuervorrichtung;

Fig. 7

in gleicher Darstellung wie Fig. 4, 5 und 6 eine Ausbildungsform der Steuervorrichtung für ein Einspritzventil, das anstelle eines Schieberventils ein Blattfederventil aufweist;

Fig. 8a

einen in der Fig. 7 mit VIII-VIII bezeichneten Querschnitt durch den dort gezeigten Teil des Brennstoffeininspritzventils;

Fig. 8b

in perspektivischer Darstellung die in der Steuervorrichtung gemäss den Fig. 7 und 8a verwendete Blattfeder;

Fig. 9a

in einem Schnitt entsprechend jenem der Fig. 8a eine weitere Ausbildungsform der Steuervorrichtung eines Einspritzventils mit einer Blattfeder;

Fig. 9b

in perspektivischer Darstellung das Blattfederelement beim Einspritzventil gemäss Fig. 9a; und

Fig. 10

im Längsschnitt und bezüglich Fig. 1 und 2 vergrössert einen Teil des dort gezeigten Brennstoffeinspritzventils mit der Elektromagnetanordnung.

The invention is explained in more detail with reference to the drawing. It shows purely schematically:

Fig. 1

in longitudinal section a fuel injector;

Fig. 2

likewise in longitudinal section and with reference to FIG. 1, enlarged part of the injection valve shown there with the control device and the electromagnet arrangement;

Fig. 3a

a cross section through the injection valve which is designated in Fig. 2 with III-III;

Fig. 3b

in perspective view parts for supporting the closing spring of the fuel injector;

Fig. 4

in longitudinal section and with reference to Figures 1 and 2 enlarged part of the fuel injector shown there with the control device.

Fig. 5

4 shows a first embodiment of the control device according to the invention;

Fig. 6

in the same representation as Figures 4 and 5, a second embodiment of the control device designed according to the invention;

Fig. 7

4, 5 and 6, an embodiment of the control device for an injection valve, which has a leaf spring valve instead of a slide valve;

Fig. 8a

a cross-section designated VIII-VIII in FIG. 7 through the part of the fuel injector shown there;

Fig. 8b

in a perspective view the leaf spring used in the control device according to FIGS. 7 and 8a;

Fig. 9a

in a section corresponding to that of Figure 8a a further embodiment of the control device of an injection valve with a leaf spring.

Fig. 9b

in a perspective view the leaf spring element in the injection valve according to FIG. 9a; and

Fig. 10

in longitudinal section and with reference to FIGS. 1 and 2 enlarged part of the fuel injector shown there with the electromagnet arrangement.

Fig. 1 shows an axial section through a fuel injector 10. This one tubular housing 12 on which one ends Valve seat element 14 and another one Electromagnet assembly 16 for the electromagnetic Control of the fuel injector 10 attached are. The housing 12 has a high-pressure inlet 18 serving bore running in the radial direction, through which a high pressure (200-2000 bar or more) of fuel in a high-pressure chamber with limited housing 20 is introduced, which is in axial Direction to the valve seat element end of the housing 12 extends. Located in this high pressure space 20 there is a needle-shaped injection valve member 22, whose axis 24 with the axis of the hollow cylindrical housing 12 coincides. By means of a between the housing 12 and the injection valve member 22 present Annular space 25 is the valve seat element 14 with the high pressure inlet 18 flow related. Inside the tubular Housing 12 is also a hydraulic Control device 26 for the injection valve member 22, which further below in connection with FIGS. 2 and 4 will be described in more detail.

The housing 12 extends through a connecting sleeve 28 a threaded flange 30 projecting in the radial direction, in which a high pressure connection piece 32 is threaded is. As can be seen in particular from FIG. 2 the wall of the high pressure connection piece 32 in the housing 12 facing end region tapered, so the width of the end-face annular Sealing surface 34 is smaller than the thickness of the wall of the High-pressure connection piece 32 at the remaining locations, whereby between the sealing surface 34 and the cooperating with it Mating surface 36 on the housing 12 at Tightening the high pressure connector 32 a high Surface pressure and thus a high pressure tight connection results. In the middle of the counter-sealing surface 36 High pressure inlet 18 of the housing 12. By means of the high pressure connection piece 32 is the connecting sleeve 28 attached to the housing 12. In this context it should be mentioned that the housing 12 on the outside, for axial Positioning the connecting sleeve 28, a Can have shoulder. In a variant not shown the high-pressure connection piece 32 has the conical one Rejuvenation on the outside, with the same effect like the taper shown on the inner wall of High pressure connection piece 32. The high pressure connection piece 32 can also be done by means other than a thread be pressed against the sealing surface 34.

As can be seen in FIG. 1, the valve seat element 14 is in known manner by means of a union nut 38 on Housing 12 attached. From the cone-shaped free outer end face 40 of the valve seat element 14 Injection nozzle holes run in a known manner 42, which open into the high pressure space 20. One too conical inner face of the Valve seat element 14 is designed as a valve seat 44 and to interact with the oppositely shaped end region of the injection valve member 22 determined. This End area separates when in the closed position Injection valve member 22, the injector holes 42 from High pressure space from or connects this with that if it is lifted from the valve seat 44 in the injection position.

How this increases FIGS. 2 and 4 compared to FIG. 1 show, the injection valve member 22 is by means of a Compression spring trained closing spring 46 in the closing direction biased. The stem 48 of the injector member 22 has a shoulder 50 on which there are two Support half-flanges 52 - see Fig. 3b - in assembled state of a first ring 54 includes and are held together. One end of the closing spring 46 is supported on this first ring 54. The other The end is supported on a second ring 54 'which is on a one-piece support flange having a slot 56 sits. This is in turn on the front of one essentially hollow cylindrical sleeve 58, which in Connection with the control device 26 closer to will be described. The one following shoulder 50 slightly tapered part of the Injection valve member 22 extends through support flange 56 with clear play, while the half-support flanges 52 in preferably practically playfree on the Injection valve member 22 sit. Since the wall of the sleeve-shaped part of the half-support flanges 52 thin can be formed, it is possible to close the closing spring 46 to be very slim in the inside diameter; this can be about the outside diameter of the injection valve member 22 correspond below the shoulder 50. Can continue the sleeves 54, 54 'for the compensation or compensation of length deviations can be used. By selection the force can be obtained from sleeves 54, 54 'of different thickness Closing spring 46 subject to manufacturing tolerances always the same in a series of fuel injectors being held.

The control device 26 is described with reference to FIG. 4. It can be seen from this that the injection valve member 22 in its end region facing away from the valve seat element 14 has a double-acting control piston 60, which in sleeve 58 in a tight sliding fit - i.e. with a Game from about 1 to 10 um - is performed. The control piston 60 limits the high pressure space 20 on the one hand and on the other hand a control space 62 which is circumferential of the sleeve 58 is limited. In the sleeve 58 is also a slide valve body 64 of a slide valve 66 in a narrow Sliding fit arranged and free in the direction of axis 24 flexibly guided. One facing the injection valve member 22 first end face 68 likewise delimits the control space 62. A second facing away from the first end face 68 End face 68 'is designed as a sealing surface and for this purpose determined, in a sealing position of the slide valve body 64 on an end face designed as a slide valve seat 70 of a control body 72 to seal, which in the housing 12, for example by means of a shrink connection is firmly arranged.

Arranged eccentrically with respect to the axis 24, runs from the first face 68 to the second face 68 ' a throttle passage through the spool valve body 64 74. On the second end face 68 ' Slider valve body 64 has a hydraulic connection 76 except that of the conically expanded on this side Mouth of the throttle passage 74 in the radial direction Axis 24 there and beyond. The connection However, 76 is on all sides of a protruding edge enclosed. The hydraulic connection 76 is with Advantage designed in such a way that the recessed area has a certain degree in order to optimally respond to the Slide valve 66 to end the injection process, too achieve.

The throttle passage is in a variant not shown 74 arranged on the axis 24. In this case there is no need the hydraulic connection 76.

In the control chamber 62 is designed as a compression spring Spring element 78 arranged on the one hand on the control piston 60 and on the other hand on the slide valve body 64 supported. The spring element engages around a central one Projection 80 of the control piston 60 and the one produced by it Force is much smaller than that of the closing spring 46th

The control body 72 has a coaxial to the axis 24 Control passage 82 on which in a the spool valve body 64 end area facing a throttle restriction 82 '. Hydraulic connection 76 connects the control passage 82 to the throttle passage 74, even if the slide valve body 64 sealing abuts the control body 74. The sleeve 58 is supported from the front on the control body 72; in their the Control body 72 facing end region is on the radial inside circumferential recess 84 available, the one in the sealing position Slide valve body 64 forms an annular groove with this, through a slot 86 in the sleeve 58 and through at least one extending in the axial direction Flow gap 88 that between the inner wall of the housing 12 and a flat on the outside of the sleeve 58 is formed, is connected to the high pressure chamber 20. As a result, there is also a gap 89 which moves when moving away the slide valve body 64 forms from the control body 72, connected to the high pressure space 20, and the entire second End face 68 'of the slide valve body 64 with high pressure applied. The control body 72 has an inclined surface 90 from which a throttle inlet 92 into the Control passage 82 leads to this with the To connect high pressure chamber 20 permanently. The throttle inlet 92 opens into the control passage 82 between the Throttle restriction 82 'and the slide valve seat 70. A with throttle restriction arranged at 90 ° to axis 24 a ground surface in the control body, or one Ring groove on the control body could also be used. The Cross sections of the recess 84, the slot 86 and the Flow gap 88 are designed much larger than the cross sections of the throttle passage 74, the Throttle restriction 82 'and the throttle passage 92, see above that no significant throttling occurs, and the Pressure in the recess 84, in the slot 86 and in Flow gap 88 is substantially the same as that in High pressure inlet 18 and in the high pressure space 20.

How this from Fig. 4 and in particular from Fig. 2 and 3a emerges, is on the tubular housing 12, of the Side of the electromagnet assembly 16 forth, another Screwed union nut 94, which has a through hole in the middle 96 distributed with three in the circumferential direction Has longitudinal grooves 96 '. In the through hole 96 is a valve pin 98 slidably disposed in the axial direction and guided radially. The control body side has the Through hole 96 has a widening recess 97, which the outflow of the during the injection of the Throttle restriction 82 'released fuel into the Longitudinal grooves 96 'favored. Instead of the longitudinal grooves 96 ' one or more holes could also be used which the recess 97 with the low pressure chamber 106th connect. In this case, bore 96 would Guide valve pin 98 radially over the entire circumference.

The union nut 94 has a hexagon 95 (Fig. 3a), with which it has the required tightening torque can be tightened. Other clamping devices not shown can also be used.

The union nut 94 holds the control body 72 on the one hand, which may be only weakly pressed into the housing 12 is fixed against the pressure in the high pressure chamber 20 and positions it exactly. On the other hand, they are Union nut 94 other important functions 10 below and in the description of FIG. 10 are explained.

When the electromagnet 100 is not energized Solenoid assembly 16, the valve pin 98 of an armature 102 of the electromagnet arrangement 16 in contact with Control body 72 held where it the control passage 82nd closes. The valve pin 98 forms together with the Control body 72 a pilot valve 104. On the Control body 72 and housing 12 side facing away from Another union nut 94 is the Low pressure space 106, which through connection channels 108 in the electromagnet arrangement 16 with a Low pressure outlet port 110 is fluidly connected. In known way leads from the low pressure outlet 110 a line back to a fuel reservoir.

The armature 102 is designed with the force of a compression spring Armature spring 112 acted upon when not energized Electromagnet 102 the valve pin 98 via the Holds armature 102 in contact with the control body 72. Will the When electromagnet 100 is excited, it pulls armature 102 back against the force of the armature spring 112, whereby the valve pin 98 can lift off the control body 72.

The operation of the training form shown in FIGS. 1 to 4 of the fuel injector 10 is like follows: it is assumed that shown in the figures mentioned State in which the injection valve member 22 in the closed position and the slide valve 66 in the sealing position located on the slide valve seat 70. Is further the electromagnet 100 is not energized, so that the Valve pin 98 closes the control passage 82. in the Control room 62 has the same pressure as in High pressure room 20.

An injection cycle is done by energizing the electromagnet 100 triggered. The armature 102 is attracted whereby the valve pin 98 stands out from the control body 72 can and thereby the control passage 74 with the low pressure chamber 106 is connected. Because the throttle restriction 82 'has a larger flow cross section than that Throttle inlet 92, the pressure in the control chamber 62 begins decline. The injection valve member 22 thereby moves away from the valve seat 44 and gives the injector holes 42 free. The injection process begins. This turns into fuel from the control chamber 62 through the throttle passage 74, the hydraulic connection 76 and the control passage 82 displaced into the low pressure space 106. During the entire opening process of the injection valve member 22 the slide valve body 64 remains in contact with Control body 72. The opening stroke of the injector member 22 is limited in that the projection 80 of the Injection valve member 22 on the slide valve body 64 for System arrives, the throttle passage 74 exposed remains. Since the narrowest flow cross section of the Throttle passage 74 is smaller than the cross section of FIG Throttle restriction 82 ', is the opening movement of the Injection valve member 22 at a given pressure and given Closing spring 46 mainly through the throttle passage 74 determined.

In a variant not shown, the Throttle passage 74 so positioned, and the face of the projection 80 so that towards the end of the Opening stroke of the throttle passage 74 from the projection 80 is closed. This e.g. in that the Throttle passage 74 is positioned on the axis 24 and the end face of the projection 80 is made sealing. This advantageously dampens the end of the opening stroke and the pressure in the control room 62 after the end of the Opening movement not or not entirely at the lower ones Pressure in the control passage 82 adjusted.

To end the injection process, the electromagnet 100 de-excited. As a result, the anchor 102 below the force of the armature spring 112, the valve pin 98 in contact moves to the control body 72. The low pressure side The mouth of the control passage 82 is closed. The Pressure in control passage 82 begins due to the connection through the throttle inlet 92 to the high pressure chamber 20 rise, which is due to the pressure difference on both End faces 68, 68 'of the slide valve body 64 and the corresponding effective areas to move the Slider valve body 64 from the sealing system on Control body 72 leads to the formation of the gap 89. At the same time, the closing spring 46 causes a movement of the injection valve member 22 in the direction of Valve seat 44 too. The negative pressure in the control room and the High pressure on the second end face 68 'leads to the fact that the slide valve body 64 in the manner of a Tandem movement together with the injection valve member 22 moves until this closes the valve seat 44 and thereby the injection process into the combustion chamber Internal combustion engine ended.

As a result of the afterflow of fuel through the Throttle passage 74 in the control chamber 62 is similar in FIG this gradually the pressure the pressure in the high pressure room 20, which causes the slide valve body 64 under the force of the spring element 78 in the sealing position moved back. The fuel injector is now ready for the next injection process.

The hydraulic efficiency of this Fuel injector 10 is very high; for the Control uses little fuel, resulting in one low backflow of fuel into that Low pressure reservoir leads. Coaxiality continues to play of the injection valve member 22 to the slide valve 66 - compared with, for example, in EP-A-1 118 765 disclosed embodiments of Fuel injectors - no matter what good Movement characteristics of both the injector member 22 as well as the slide valve body 64 leads.

5 shows a first embodiment according to the invention the control device 26. Otherwise, this is Fuel injector 10 is the same as in the 1 to 4 and described above. in the following only the differences from that Form of training received. For same and parts with the same effect become the same reference symbols used.

The control piston 60 has a circumferential bead 114 with a stop shoulder 114 'in its end region facing the high pressure chamber 20. This is intended to cooperate with a counter-stop shoulder 116 formed on the sleeve 58. Otherwise, the bead 114 does not touch the sleeve 58. When the injection valve member 22 is in the closed position, the stop shoulder 114 ′ and the counter stop shoulder 116 are spaced apart from one another by a distance S ₁ . A further bead 118 is formed on the circumferential side of the slide valve body 64 and forms a further stop shoulder 118 '. This is intended to cooperate with a further counter stop shoulder 120 formed on the sleeve 58. This is formed by the axial delimitation of the recess 84. With the slide valve body 64 in the sealing position, the distance between the further stop shoulder 118 ′ and the further counter-stop shoulder 120 is a length S ₂ . S ₃ denotes the distance from the projection 80 of the injection valve 22 to the slide valve body 64 when the slide valve body 64 is in the sealing position and the injection valve member 22 is in the closed position. The gaps formed by these distances S ₁ , S ₂ and S ₃ are designed such that the gap with S ₁ designated gap is larger than that designated S ₂ and smaller than that designated S ₃ .

The slide valve body 64 has a further throttle passage 122, which is between the first and the extends second end 68, 68 'and in the sealing position located slide valve body 64 by the Slider valve seat 70 on the control body 72 is closed. With the slide valve body lifted off the control body 72 64 connects the further throttle passage 122 in parallel to the throttle passage 74 with the control chamber 62 the high pressure space 20.

Furthermore, the slide valve body 64 on the Control body 72 facing side a chamfer 124, by means of which, depending on the size, the high pressure was applied active surface of the valve slide body 64 selected can be. The circle diameter at the outer edge of the Slider valve seat 70 can therefore be larger, the same size or smaller than the guide diameter of the Slide valve 64 in the sleeve 58.

At the beginning of an injection process and as long as the pilot valve 104 is open, the further throttle passage 122 has no effect; the injection valve member 22 opens in the same way as in the embodiment according to FIGS. 1-4 until the stop shoulder 114 ′ and the counter stop shoulder 116 touched and ended the opening process. Since S ₃ > S ₁ , the end face of the projection 80 does not touch the first end face 68 of the slide valve body 64. In embodiments with a stop shoulder 114 ′ on the injection valve member 22 and a counter stop shoulder 116, it can be avoided that the injection valve member 22 hits the slide valve body 64 when the fuel injection valve 10 is opened. This can extend the lifespan.

Only when the pilot valve 104 is closed and with it associated lifting of the slide valve body 64 from the Slide valve seat 70 - in the same way as described above - will be the next Throttle passage 122 released, which between the Control room 62 and high pressure room 20 a faster one Pressure equalization takes place than in one embodiment without further throttle passage 122. This leads to a moving back earlier and faster Slider valve body 64 in the sealing position. With others Words, fuel injector 10 is faster for ready for another injection, which is a Pre-injection, post-injection or one Multiple injection with short intervals possible. By dimensioning the further throttle passage 122, the return movement of the slide valve 66 can Requirements are set accordingly.

Also the slide valve body 64 in the embodiment of the fuel injection valve 10 according to FIGS. 1 to 4 can have a further throttle passage 122 analogous to FIG. 5 exhibit.

A stroke limitation for the slide valve body 64 by means of the further stop shoulder 118 ′ and the further counter stop 120 also leads to the slide valve body 64 reaching its sealing position again very quickly, since S ₂ <S ₁ . The tandem movement of slide valve body 64 and injection valve member 22 is canceled as soon as the further stop shoulder 118 ′ comes to bear against the further counter-stop shoulder 120. At the same time, this measure can advantageously dampen the blow of the injection valve member 22 onto the valve seat 44 as a result of the refilling of the control chamber 62 which is throttled without tandem movement over the throttle passage 74 and the further throttle passage 122. All of these measures can also be taken independently of one another in the other types of training.

In the second embodiment shown in FIG. 6 of the fuel injector 10 according to the invention also uses the same reference numerals as in the embodiments described above and will only dealt with the differences from those.

The control body 72 is no longer seated in the tubular Housing 12, but is placed on the end face of this and through a corresponding recess in the further Union nut 94 held centrally and at the upper end of the tubular housing 12 pressed sealingly. center and runs through the control body 72 in the axial direction through the control passage 82; throttle inlet 92 is now in the slide valve body 64. He opens into the throttle passage 74 on the with regard to the narrowest cross section of the control body 72 facing side. The communicates further Throttle inlet 92 through the recess 84, the gap 86 and the flow gap 88 with the high pressure space 20.

The slide valve body 64 shown in FIG. 6 is like 5 with another Throttle passage 122 and another stop shoulder 118 'equipped with the further counter stop shoulder 120 cooperates on the sleeve 58.

Fig. 6 shows a further embodiment of the injection valve member 22, namely by the control piston 60 and the shaft 48 are formed as individual parts. The For example, connection between these parts by means of a press fit, by a tight fit or done by welding. The shaft 48 can also Penetrate control piston 60. In this case the Projection 80 formed from the upper end of the shaft 48, and the control piston 60 is a sleeve with a continuous Bore that, as mentioned above, with shaft 48 can be put together.

The mode of operation of the form of training shown in FIG. 6 the control device 26 is the same as in that according to FIG. 5.

The embodiment shown in Figs. 7, 8a and 8b also has a tubular housing 12 in which the Control body 72 is arranged fixed. With her the Control chamber 62 facing the end of the sleeve is supported 58, in which the double-acting control piston 60 of the Injector member 22 in a tight fit in the axial Direction is arranged, now sealing from and without hydraulic connection to the high pressure room 20. How described above is based on the sleeve 58 the side facing away from the control body 72, the Closing spring 46 for the injection valve member 22. The Control chamber 62 is thus on the one hand from control piston 60, circumferentially from the sleeve 58 and on the other hand from Control body 72 limited.

The control body 72 points centrally and in the direction of Axis 24 extending the control passage 82, in which the radial throttle inlet 92 empties. This is due to milling on the outside 128 and the flow gap 88 between the sleeve 58 and the housing 12 connected to the high pressure space 20. Of the the end face of the control body facing the control chamber 62 72 runs through this to the throttle inlet 92 130. This opens into the throttle inlet 92 on the with regard to the narrowest flow cross-section the high pressure space 20 facing side.

Both the mouth of the control passage on the control room side 82 as well as those of the bore 130 are by means of a leaf spring Tongue 132 covered, the shape of which from Fig. 8a and 8b can be seen. At the bore 130 facing away At the end, the tongue 132 is welded to the control body 72. The welding point is labeled 134. The tongue 132 has a throttle passage 74 coaxial with the axis 24 which connects the control chamber 62 with the control passage 82 combines. Here, too, the throttle restriction 82 'is in the Control passage 82 larger in cross section than that narrowest cross section of the throttle inlet 92 and Cross section of throttle passage 74. The narrowest Cross section 82 'of the control passage 82 is on the outlet side with a bore 83 of slightly larger cross section connected. The bore 83 is preferably relatively long, compare with its diameter, at least 2 to 10 times as long. With this, the flow becomes the narrowest Cross section 82 'again the full, larger cross section 83 fill out what the flow through the narrowest Cross section 82 'favors. Otherwise it is Fuel injector designed the same as in the 1 to 4 shown.

The control device 26 according to FIGS. 7, 8a and 8b works as follows. For a description of how it works of the fuel injection valve 10 with a control device 26 according to FIGS. 7, 8a and 8b, as in connection with the embodiments described above, assumed from the state of rest, in which the Injection valve member 22 is in the closed position and the pressure in the control chamber 62 the pressure in the high pressure chamber 20 equivalent. The pilot valve 104 is activated by the Valve pin 98 on the control body 72 closed.

When the electromagnet 100 is excited (see FIG. 2) due to the high pressure present in the control passage 82 the valve pin 98 is lifted from the control body 72. The Control passage 82 is thereby with the low pressure chamber 106 (see Fig. 2) connected. The pressure in the control passage 82 decreases, resulting in fuel due to the pressure difference through the throttle passage 74 from the control chamber 62 in the Control passage 82 flows. As soon as the pressure in the control room 62 has dropped so far that the negative pressure related to the pressure in the high pressure chamber 20 is sufficient to the force of To overcome closing spring 46, the injection valve member moves 22 away from the valve seat 44, causing the injection process starts. When the electromagnet is de-energized 100, valve pin 98 rests on control body 72 on, whereby the control passage 82 from the low pressure space is separated. On the side facing away from the control room 62 On the side of the tongue 32, the pressure in the control passage 82 rises at what as a result of the expansion of the tax relief and the pressure in the bore 130 to bend the tongue 132 leads. As a result of the release of the tax passage 82 and The bore 130 now passes fuel through a larger one Flow cross section in the control room 62, which too a rapid pressure increase in the control room 62 and faster movement of the injection valve member 22 on the Valve seat 44 leads. By dimensioning the corresponding passages and the properties of the tongue 132 may affect the performance of the fuel injector be designed according to the requirements.

In the embodiment according to FIGS. 7, 8a and 8b touches the face of the spool 60 at the end of the Opening process of the injection valve member 22 die Underside of the leaf spring-like tongue 132, and holds this pressed on the underside of the control body 72. On unintentional, uncontrolled opening of the tongue 132 and consequently bore 130 when fully open Insert valve 22 is thus avoided. This solution is in this respect analogous to the solution of FIGS. 1 to 4, at which pressed the slide valve 66 from the projection 80 is held. Also in the form of training according to FIG. 7 to 8b, the end face of the control piston 60 - or a head start - be designed so that in the end of the opening stroke of the throttle passage 74 is closed is, and the pressure in the control room 62 not or not entirely matched to the lowest pressure in the control passage 82 becomes.

On the other hand, the control piston 60 could be analogous to that in FIG. 5 have a circumferential bead shown with his stop shoulder and a counter stop shoulder cooperates to the stroke of the injection valve member 22 limit before the face of the spool 60 the Underside of the tongue 132 touched.

9a and 9b show the same representation as that 8a and 8b a section VIII-VIII according to FIG. 7 and the tongue 132 in a different training form. The tongue 132 is integrally formed on a retaining ring 136. The retaining ring 136 is on at least one preferably at several points, for example at the with 134 designated welding points on the control body 72 welded. The leaf spring element according to FIG. 9b create yourself in a simple way by using a circular spring steel disc has a C-shaped groove is punched out. How the fuel injector works 10 with a control device 26 7, but with an embodiment of the tongue 132 according to FIGS. 9a and 9b, is the same as the next described above in connection with FIGS. 7, 8a and 8b.

As in particular from FIG. 10 in conjunction with the 2 and 3a shows the electromagnet arrangement 16 a housing sleeve 138 with a molded on the inside circumferential ring 140 on. The ring 140 defines a contact surface 142 with which it is mounted Condition on a flat outer surface 144 of the others Union nut 94 abuts. This is the axial position of the electromagnet assembly 16 defined. One in axial Part 143 protruding over the contact surface 142 the housing sleeve 138 encompasses the further union nut 94, which also changes the radial position of the Electromagnet assembly 16 is defined. An O-ring 146 seals the low pressure space 106 from the environment. A runs around the further union nut 94 Threaded ring 148, on the one hand on a rotating Shoulder 149 of the further union nut 94 supports and on the other hand with its internal thread 149 'with a External thread 143 'screwed to the housing sleeve 138 is.

The ring 140 sits on the surface facing away from the contact surface 142 Side an annular magnetic closing plate 150. An this is also supported in the axial direction as Ring body trained magnetic body 152, which on the side facing the magnetic closing plate 150 the axis 124 has a circumferential annular groove 154. In this is the coil 155, which is via electrical coil connection conductors 156 - only one is shown in FIG. 10 - Is connected to an electrical control device.

On the side of the magnetic plate facing away from the Magnetic body 152 is a holding body 158, the can consist of an anti-magnetic material. In a circumferential groove of the circumferentially arranged Holding body 158, another O-ring 160 is inserted, which rests on the inside of the housing sleeve 138 and corresponding to the low pressure space 106 from the environment seals off. The end region of this side of the Housing sleeve 138 is bent towards the inside (possibly flanged) and lies on a truncated cone Shell surface section of the holding body 158. Thereby are the magnetic closing plate 150, the magnetic body 152 and the holding body 158 held firmly in the housing sleeve 138.

The holding body 158 projects in the axial direction with a Stub 164 protrudes from the housing sleeve 138. In the Stub 164 is the low pressure connection piece 110 threaded.

The anchor 102 has one welded to an anchor shaft 166 Anchor ring 168 on in the radial direction seen inside the magnetic plate 150 under formation a narrow air gap is arranged. The anchorage 166 is guided in a stop sleeve 170, which on Magnetic body 152 seen in the axial direction on one Support shoulder 172 is supported. The stop sleeve 170 is with the magnetic body 152 at 174 as shown welded or flanged. The stop sleeve 170 forms an axial stop for one formed on the armature shaft 166 Ring shoulder 176 and ensures that between the armature ring 168 and the magnetic body 152 a gap free remains when the armature 102 is removed from the electromagnet 100 is attracted. Adjacent to the radially inner one The end of the magnetic closing plate 150 has this on the Magnetic body 152 facing side a circumferential Recess 178 on that in the axial direction running connection holes 180 through the Magnetic closing plate 150 always with the Low pressure space 106 is connected. This enables one very rapid pressure equalization between the two sides of the Anchor rings 168 during the movement of anchor 102.

The armature 102 has one axially over the armature ring 168 Nose 182 protruding toward valve pin 98 on, which is intended together with the valve pin 98 to act. The nose 182 has a transverse bore 184 in a blind hole 186 in the anchor shaft 166 empties. The anchor shaft 166 stands on the nose 182 opposite side with an end region in the axial direction about the stop sleeve 170. There is in the anchorage 166 a suppository 190 inserted, on which on the other hand supports the armature spring 112. Further cross holes 184 'in anchor shaft 166 connect its blind hole 186 adjacent to the suppository 190 with an im Holding body 158 arranged space 192, which with the Low pressure outlet connector 110 connected in terms of flow and in which the armature spring 112 is supported located on the holding body 158. The one through the blind hole 186, the cross holes 184, 184 'and the space 192 formed connection channel 108 connects the low pressure space 106 with the low pressure connection piece 110.

In the situation shown in FIGS. 2 and 10, the Solenoid 100 is not energized, causing valve pin 98 due to the force exerted by the armature spring 112 in System is held on the control body 72. Will the electromagnet 100 excited, the anchor ring 168 together with the Anchor shaft 166 while reducing the gap between the armature ring 168 and the magnetic body 152 attracted what causes the valve pin 98 to move axially can move away from the control body 72, resulting in a Injection process leads. When the electromagnet is de-energized the armature 102 is moved by the force of the armature spring 112 in moves in the opposite direction, resulting in the valve pin 98 the throttle passage in the control body 72 closes, whereby the injection process is ended.

Because of the scattering involved in the manufacture Anchor springs 112 is used to achieve high accuracy Injection processes necessary, the electromagnet arrangement 16 to calibrate. This is done by selecting one suitable suppository 190. For this purpose suppositories 190 with different axial spacing of the surfaces, with which the suppository on the one hand on anchor shaft 166 and on the other hand, bear against the armature spring 112 posed. The contact surface serves as the basis for the measuring device 142. To simplify the calibration process Replacement of suppositories 190 are to be ensured preferably both the largest outside diameter of the Suppository 190 as well as the outside diameter of the spring 112 smaller than the guide diameter of anchor shaft 166 in the stop sleeve 170.

The length of the valve pin 98 can also be selected in Dependence on the stroke that the armature 102 is to travel. The outer surface 144 serves as the basis for measuring the Distance between this surface and the control body 72.

The different embodiments of the inventive Fuel injector 10 have a slim Build on and offer a number of options to adapt the properties to the desired course of the injection process.

The control devices 26 according to the invention can also with otherwise differently constructed fuel injection valves be used; so also with fuel injectors, where the fuel is over one separate channel, and not coaxial to or on the axis 24 of the injector but to the side of it, in the housing Valve seat element is supplied.

The electromagnet arrangement shown and described and their attachment to the housing of the fuel injector can with different fuel injectors be used.

The tubular housing can also be used instead of a thread differently trained, generally known means of fastening have an electromagnet arrangement.

A tubular housing with mounting options on the one hand for a valve seat element and on the other hand one Electromagnet arrangement and a connecting sleeve with High pressure connection spigots can also be different trained fuel injectors are used.

An injection valve member, as described above, at that the shaft and the control piston as individual parts can be made at any Find fuel injectors.

Claims (18)

Fuel injection valve for intermittent fuel injection into the combustion chamber of an internal combustion engine, with a housing (12) having a high-pressure inlet (18) for the fuel, a housing (12) intended for interaction with a valve seat element (14), which is arranged to be longitudinally movable in the housing (12) and towards the valve seat element (14) spring-loaded injection valve member (22), a double-acting control piston (60) arranged on the injection valve member (14), which on the one hand delimits a high-pressure chamber (20) which is connected to the high-pressure inlet (18) and on the other hand a control chamber (62), one in a sliding fit guided slide valve body (64), which also has a first end face (68) delimiting the control chamber (62), a second end face (68 ') opposite this and a throttle passage (74) extending between these end faces (68, 68'), one one with the second end face (68 ') of the slide valve rpers (64) cooperating slide valve seat (70) having a control body (72) which has a control passage (82) which starts from the slide valve seat (70) and is flow-connected to the throttle passage (74) and can be connected to a low pressure chamber (106) by means of a pilot valve (104) wherein the throttle passage (74) and the control passage (82) are flow-connected via a throttle inlet (92) and on lifting the spool valve body (64) by the slider valve seat (70) forming the gap (89) with the high-pressure chamber (20), characterized that the slide valve body (64) has a further throttle passage (122) opening into the control chamber (62), which is closed when the slide valve body (64) bears against the control body (72) and when the slide valve body (64) is lifted from the control body (72) High pressure chamber (20) is connected. Fuel injection valve according to Claim 1, characterized in that the further throttle passage (122) is closed by the control body (72) when the slide valve body (64) is in contact with the control body (72). Fuel injection valve according to Claim 1 or 2, characterized in that the control passage (82) and the throttle passage (74) are arranged offset with respect to one another and, when the slide valve body (64) abuts the control body (72), one from the control body (72) and slide valve body (64) limited passage (76) connects said passages (82, 74) to each other. Fuel injection valve according to one of claims 1 to 3, characterized in that the smallest cross section of the throttle inlet (92) and the throttle passage (74) is smaller than the smallest cross section (82 ') of the control passage (82). Fuel injection valve according to one of Claims 1 to 4, characterized in that the control piston (60) and the slide valve body (64) are arranged in a common sleeve (58) which laterally delimits the control chamber (58) with a sliding fit. Fuel injection valve according to Claim 5, characterized in that the sleeve (58) has a counter-stop (116) which interacts with a stop (114 ') of the injection valve member (22). Fuel injection valve according to Claim 5 or 6, characterized in that the sleeve (58) has a further counter-stop (120) which interacts with a stop (118 ') of the slide valve body (64). Fuel injection valve according to Claims 6 and 7, characterized in that the distance (S1) between the counter-stop (116) and the stop (114 ') of the injection valve member (22), when the injection valve member (22) is in the closed position, is on the one hand larger than that Distance (S ₂ ) between the further counter stop (120) and the stop (118 ') of the slide valve body (64), measured when the slide valve body (64) abuts the control body (72), and on the other hand is smaller than the distance (S ₃ ) between the slide valve body (64) and the end of the injection valve member (22) facing this. Fuel injection valve according to one of Claims 1 to 8, characterized in that the housing (12) is a tubular body which delimits the high-pressure space (20) on the circumference and has a high-pressure inlet (18) running in the radial direction, in the high-pressure space (20) in a needle-like manner trained injection valve member (22) - with the formation of an annular space (25) between the shaft (48) of the injection valve member (22) and the tubular body - the annular space (25) extends up to the valve seat element (14) facing the end of the tubular body extends and the tubular body in an end region facing away from the valve seat element (14) has means for fastening an electromagnet arrangement (16) for controlling the pilot valve (104). Fuel injection valve according to Claim 9, characterized in that a union nut (94) with an axial passage (96) is screwed onto the tubular body in the base part, a valve pin (98) is arranged in the axial passage (96), which on the one hand is in contact with the control body (76 ) closes the control passage (82) and on the other hand interacts with an armature (102) of the electromagnet arrangement (16). Fuel injection valve according to Claim 10, characterized in that the length of the valve pin (98) can be selected as a function of the desired stroke of the armature (102) and the thickness of the base part. Fuel injection valve according to one of Claims 1 to 11, characterized in that the injection valve member (22) has the control piston (60) and an individually produced shaft (48) fastened thereon. Fuel injection valve for intermittent fuel injection into the combustion chamber of an internal combustion engine, with a housing (12) having a high-pressure inlet (18) for the fuel, a housing (12) intended for interaction with a valve seat element (14), which is arranged to be longitudinally movable in the housing (12) and towards the valve seat element (14) spring-loaded injection valve member (22), a double-acting control piston (60) arranged on the injection valve member (22), which on the one hand delimits a high-pressure chamber (20) which is connected to the high-pressure inlet (18) and on the other hand controls a control chamber (62), also the control chamber (22) delimiting control body (72) which has a control passage (82) starting from the control chamber (62), connected to the high pressure chamber (20) via a throttle inlet (92) and connectable to a low pressure chamber (106) by means of a pilot valve (104), one connecting the high pressure chamber (20) with the control chamber (62) Inflow channel (130) with its own opening, and a valve member closing the inflow channel (130) and the control passage (82) in the closed position, which has a throttle passage (74) connecting the control chamber (62) with the control passage (82), characterized in that that the valve member is designed as a leaf-like tongue (132) fastened at one end. Fuel injection valve according to claim 13, d.g.d. the Tongue is attached to the control body (72) and in Hibernate is present at this. Fuel injection valve according to Claim 13 or 14, characterized in that the tongue (132) is integrally formed on a retaining ring (136) which surrounds it. Fuel injection valve according to one of claims 13 to 15, characterized in that the tongue (132) or the retaining ring (136) is welded to the control body (72). Fuel injection valve according to one of Claims 1 to 16, characterized in that the injection valve member (22) engages through a closing spring (46) which is designed as a spiral spring and which, on the one hand, engages around a first ring (54) which grips two half-support flanges (52) seated on the injection valve member (22) ) and on the other hand is supported on a second ring (54 ') which is integral and has a slot, is fixed to the housing and supports the injection flange (22) and has support flange (56). Fuel injection valve according to one of Claims 1 to 17, characterized in that the pilot valve (104) is actuated by means of an electromagnet arrangement (16) arranged in a housing sleeve (138), and the housing sleeve (138) has a contact surface (142) with which it in the assembled state rests on an outer surface (144) fixed to the housing.

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