EP0897469B1 - Magnetic valve - Google Patents

Abstract

The invention relates to a magnetic valve (30) with a magnet armature (28, 27) consisting of several members, an armature plate (28) and an anchor bolt (27) that is guided into a sliding piece (34). A damping device is fitted to the magnet armature (28) in order to prevent armature plate (28) backlash once the magnetic valve (30) is closed. Said device makes it possible to meet the exact requirements of short magnetic-valve switching times. The magnetic valve (30) is to be used with common rail injection systems.

Description

State of the art

The invention relates to a solenoid valve according to the Genus of the main claim. Such a solenoid valve is known from EP 0 690 223 A2. This will be there for control an electrically controlled fuel injection valve used. The valve needle of the fuel injection valve is in this case of prevailing in a control room pressure in Closing direction loaded. The solenoid valve works in known manner so that it is to initiate the injection a discharge of the control room initiates when the magnet of the solenoid valve is energized and thus the valve needle of the Injection valve under the action of the other hand on her acting high pressure is lifted from its seat. In which Solenoid valve, the armature is firmly connected to an anchor bolt, on which in turn the valve member of the solenoid valve sitting.

The disadvantage of the known solenoid valve is that it in operation to a swinging of the anchor and / or bouncing the valve member may come, which is particularly disadvantageous is when a fast switching sequence of the solenoid valve is required and controlled by the solenoid valve a divided into a pilot injection and main injection Injection should be made.

It has also been proposed, the moving mass the unit anchor and valve member thereby reduce that the armature movably connected to one with the valve member Part is led. But even here there is a disadvantage in that the armature after a touchdown of the valve member resonates in his seat. By such a swing the armature takes an undefined after a pre-injection Position, which may have the consequence that it in the following Main injection at different opening times the solenoid valve can come with the same control, which a dispersion of the start of injection or the injection quantity caused.

From EP 0 753 658 A1 is a solenoid valve for control an injection valve of a fuel injection device known. This solenoid valve has an electromagnet with Magnetic pole, an anchor in one with fuel filled space is arranged and moved with the anchor and of a valve closing spring in the closing direction acted upon valve member. This valve member cooperates with a valve seat, wherein the armature relative to a, connected to the valve closing member intermediate part, the in a stationary in the solenoid valve arranged slider is guided, is displaceable. This shift of the anchor takes place in the closing direction of the valve member under the action its inertial mass against a restoring force.

Advantages of the invention

The solenoid valve with the characterizing features of Main claim has the advantage that a Bouncing the valve member at its seat and a undefined ringing of the armature can be prevented so that after closing the solenoid valve the Valve member maintains its closed position and the anchor after a deliberate first evasive movement quickly his again Rest position reached before the main injection starts.

drawing

Fig. 1 einen Schnitt durch einen Teil eines Einspritzventils mit dem erfindungsgemäßen Magnetventil im Schnitt, mit einem, auf einem Bolzen, der mit dem Ventilglied des Magnetventils verbundenen ist, verschiebbaren Anker,

Fig. 2 eine Begrenzung der Ankerverschiebung, Fig. 3 eine erfindungsgemäße Ausführung mit einer Scheibe zur Einstellung der Begrenzung der Ankerverschiebung, Fig. 4 eine Variante der Erfindung mit einer vergrößerten Aufschlagfläche des Ankers, Fig. 5 eine Ausführung der Anordnung mit einer alternativen Ausführung einer Rückführfeder für den Anker und Fig. 6 ein Diagramm über den Hubverlauf des Ankers bei einem Schließvorgang des Magnetventils.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. Show it:

1 shows a section through a part of an injection valve with the solenoid valve according to the invention in section, with a, on a bolt which is connected to the valve member of the solenoid valve, displaceable armature,

4 shows a variant of the invention with an enlarged impact surface of the armature, FIG. 5 shows an embodiment of the arrangement with an alternative embodiment of an anchor Return spring for the armature and Fig. 6 is a diagram of the stroke of the armature in a closing operation of the solenoid valve.

Description of the embodiments

1 shows a partial section through an electrical controlled injection valve 1 as it is, for example The above-mentioned prior art is known. One such injector is for use in a fuel injection system determined with a high-pressure fuel storage equipped by a high-pressure pump continuously supplied with high-pressure fuel and from this fuel under injection pressure via individual electrically controlled injectors of Internal combustion engine can be supplied. That in part and Injector 1 shown in section has an injection valve housing 4 on with a longitudinal bore 5, in the a valve piston 6 is received, which at its one End acts on a valve needle, not shown, which in turn, in known, e.g. in the aforementioned EP 0 690 223 shown with injection ports of the Fuel injection valve cooperates. The valve piston 6 serves to actuate the valve needle in the closed position, which in turn constantly acting in an opening direction High pressure is exposed, which has an im Valve housing 4 extending in the longitudinal direction of the pressure bore. 8 supplied from the high-pressure accumulator ago. About this hole the injection openings are also the amount of fuel to be injected fed into the combustion chamber of the associated Internal combustion engine is injected. For the connection of the Pressure hole 8 to the high-pressure accumulator is a connecting piece 9 provided on the valve housing 4.

The valve piston 6 is at its not shown Valve needle opposite end in a cylinder bore 11 out, which is introduced in a valve piece 12 is. In this cylinder bore, the end 13 closes of the valve piston a control pressure chamber 14, which is constantly via a radial through the wall of the valve piece leading Throttle bore 15 with a valve piece on the circumference surrounding annular space 16 is connected, which is also in permanent connection with the connecting piece 9 is and the in the high-pressure fuel storage prevailing high fuel pressure is exposed.

Coaxially to the valve piston 6 branches from the control pressure chamber fourteenth a running in the valve piece 12 bore 17 from which a Relief throttle 18 contains and in a discharge space 19 opens, the here in a manner not shown with a fuel return of the injection valve is connected. The exit of the bore 17 from the valve piece takes place in Area of a tapered countersunk part 21 of the outer Front side of the valve piece 12. The valve piece 12 is in a flange 22 fixed over a Screw member 23 clamped to the valve housing 4.

In the area of the exit of the bore 17 in the conical Part 21 is a valve seat 24 is formed, with a Valve member 25 of the injection valve controlling solenoid valve 30 works together. The valve member 25 is above a Intermediate part in the form of an anchor bolt 27 with an anchor 28, connected to an electromagnet 29 of the solenoid valve 30 acts together and displaceable with the anchor bolt is coupled. The anchor has the shape of a with a Guide stub 39 provided anchor plate 28 and is under Influence of its inertial mass against the biasing force of a Return spring 35 dynamically displaceable on the anchor bolt 27 stored and is by this return spring 35 in the idle state pressed against a stop ring 26 on the pin 27. The Return spring 35 is fixed to the housing via a flange 32 of an anchor bolt leading slider 34, the with this flange between valve member 12 and screw 23 in the solenoid 29 receiving solenoid valve housing 37 is firmly clamped. The anchor bolt 27 and with him the anchor plate 28 and the moved by the anchor bolt Valve member 25 are constantly fixed by a housing supporting closing spring 31 acted upon in the closing direction, so that the valve member 25 is normally in the closed position seated on the valve seat 24. Upon excitation of the electromagnet the armature plate 28 is attracted by the electromagnet and while the bore 17 and 18 to the discharge space 19th opened.

Between the valve member 25 and the anchor plate 28 is located itself as a stop member an annular shoulder 33 on the anchor bolt 27, the energized solenoid on the flange 32 of the Geleitstücks 34 abuts and so the opening stroke of the valve member 25 limited. To adjust the opening stroke is between flange 32 and valve member 12 a shim 38 inserted.

The opening and closing of the valve needle is in the following Way controlled by the solenoid valve. In closed position of the solenoid valve member 25 is the control pressure chamber 14 to Relief side 19 closed, so that over there the inlet via the throttle 15 very quickly the high pressure which also in the high-pressure fuel storage pending. Over the surface of the end face 13 generates the pressure in the control pressure chamber 14, a closing force on the valve needle, which is larger than the other in the opening direction in Result of the upcoming high pressure acting forces. Will the Control pressure chamber 14 by opening the solenoid valve to the discharge side 19 open, the pressure builds in the small volume of the control pressure chamber 14 very quickly, because of this via the throttle bore 15 from the high pressure side disconnected. As a result, it outweighs the valve needle in the opening direction acting force from the at the Valve needle pending fuel high pressure, so this moved upwards, while the injection ports for injection be opened. Closes the solenoid valve, however 30, the bore 17 and 18 again, the pressure in the Control pressure chamber 14 through the via the throttle bore 15th still flowing fuel very quickly again be built so that the original closing force currently pending and the valve needle of the fuel injection valve closes. These tax transactions are also enough to realize very short injection times, as they do for a pre-main injection Pre-injection in a known manner is necessary.

Nevertheless, high demands of the solenoid valve Switching accuracy to provide. In particular, join in a bouncing of the valve member and vibration effects such as mentioned at the beginning adversely noticeable. A bouncing arises then when a relatively large mass accelerates and then abruptly slowed down when anchor bolt with Anchor plate and valve member as mass on the valve seat crack open. But because now an essential part of mass moved by the anchor, the anchor plate, displaceable stored on the other moving part, the anchor bolt is, after placing the valve member 25 on the Valve seat 24, the anchor plate 28 against the force of Move return spring 35, so that once the effective braked mass becomes lower and the elastic deformation of the valve seat as energy storage, which leads to the disadvantageous Rebounding of the valve member leads, now lower is. The trailing anchor plate also generates a the compression of the return spring 35 increasing dynamic force on the valve member, which is the valve member additionally sturdy holds at its seat and the bouncing counteracts. With the compression of the return spring 35 this is decoupled from the closing spring, so that the full Biasing force of the closing spring acts on the valve member. However, the tracking can then disadvantageously a considerable swinging of the anchor plate 28 against the Return spring 35 generate, so that the position of the Anchor plate at an immediately afterwards required Actuation of the valve member is undefined and turn on of the solenoid valve not fast enough and with reproducible constant switching time takes place.

In a further development of the embodiment of Figure 1 is therefore the anchor according to Figure 2 in its displaceability has been restricted. The figure 2 shows only the from the Figure 1 apparent part of the anchor bolt 27 'with the Anchor plate 28 'and the slider 34'. The anchor plate closes as in the embodiment of Figure 1 plane-parallel to the pole 61 (see FIG. 3) of the electromagnet 29 and goes into a greatly shortened guide sleeve 39 ' over which slides on the anchor bolt 27 '. The glide path of Anchor plate will turn on one side by a Stop, now in the form of an end-face head 36 am Anchor bolt 27 ', and on the other side by the plant of the guide stub 39 'with its end face 40 on the Front side 41 of the slider 34 'limited. The compression spring 35 normally holds the anchor plate 28 'in abutment with the Head 36 as shown in FIG. The front sides 40 and 41 make with increasing approach to a dynamic triggered displacement of the anchor plate on the anchor bolt between them a nip that is in the fuel filled space in the housing of the solenoid valve a drag generated, which counteracts the movement of the anchor plate. This counterforce is the more effective the lower the kinetic energy of the anchor plate as it approaches the slider 34 'is. By matching the size of the free path of the anchor plate, the size of the restoring force a possibly provided return spring and the size of the Moving surfaces can approach one another the anchor plate can be optimized for given periods. The given period is, e.g. between one Pre-injection and a main injection, in front of the Anchor plate reaches a reproducible secured position should have.

Has the anchor bolt the valve member 25 in its closed position brought so in the episode by the at the Trailing movement of the anchor plate occurring compression of the Return spring 35 increases and at the same time the running of the Anchor plate 28 'braked in cooperation of the return spring on the one hand and the damping effect of each other approaching end faces 40 and 41 on the other hand so that this quickly back to their reproducible constant starting position is returned to the stop 36. The return spring 35 is designed here as a conical spring, bringing a small space can be achieved with fully effective travel. In the anchor plate 28 'are overflow openings 42 for the when working the solenoid valve displaced fuel intended.

The effectiveness of the arrangement according to the invention is the Figure 6 can be seen. There is time over the abscissa plotted and on the ordinate the movement of the anchor with Anchor bolt and anchor plate. You can see an increase the curve A, which reaches a plateau at the time tö at due to the attraction of the electromagnet 29 of the Anchor has executed its largest hub and the connection 18 to the control pressure chamber 14 has completely opened. At the time ts is for the purpose of closing the solenoid valve the Excitation of the electromagnet interrupted. It happens when placing the valve member on its seat 24 to a Overshoot of the anchor plate 28, which is indicated by the dashed line Curve is shown. The anchor bolt 27 with valve member 25th first stays in the position of the solid line. Due to the overshoot, it can be seen that at time ts' the returning anchor plate reopening the valve generated by the anchor bolt briefly again is lifted. This will happen in the episode two more in the example shown. Will however the Evasive movement of the anchor plate by the position of the Slider 34 limited to Figure 2, which in the figure as black bar is shown, then there is a Reversing the movement of the anchor plate after previous damping and a short decay of the same according to the curve B. A Damping shortly before placing the anchor plate on the fixed part, here according to Figure 2, the slider 34 ' reduces the reversing momentum after impact Anchor plate on the slider 34 '.

In a modification of the embodiment of Figure 2 is in Figure 3 the guide piece 139 running longer and it can therefore a return spring 135 may be used, the more Has spring coils and therefore with respect to their Spring behavior, e.g. Progressiveness, better designed can be. In addition, due to the longer neck 139 improved the leadership of the anchor.

Departing from Figure 1, the slider 134 is configured to that there is a shoulder 53 of the injection valve body overlaps. On the front side 141 is a first shim 54, which has a recess 55 for implementation of the anchor bolt 127 and between the Shoulder 53 and flange 132 is still a second dial 57 provided. The first dial is through an end face 56 of the solenoid valve housing 37 on the Flange 132 pressed and over this and the second Adjusting washer on the shoulder 53 of the injection valve pressed, so that the shims and the Slider fixed together fixed. With the help of Thickness of the second dial is the distance of the Slider 134 adjustable from the valve seat 24, so that through the determination of the front side of the slider 134 for Appendix coming annular shoulder 33 the maximum opening stroke the valve member 25 of the solenoid valve can be adjusted can. At the same time, a residual air gap 60 between the Front side of the armature disk 28 and the pole 61 of the electromagnet Affected, which must be designed so that a Magnetic bonding after the de-energizing of the electromagnet is avoided. With the thickness of the first shim 54 however, the path 62 is set, the anchor plate against the force of the return spring after placing the Valve member 25 on the valve seat 24 during the closing operation the solenoid valve can cover. As this disc too the distance of the pole 61 of the electromagnet from the flange of Slider 134 and thus the distance of the anchor plate 28 of the Pol 61 changed, is at the same time with this . Adjustment also affects the residual air gap 60.

Instead of this first dial 54 will be advantageous also provided two slices at this point, an outer, the residual air gap determining disc and an inner, the off the anchor plate determining disk loosing there can be inserted. In addition, however, this inner Disc also by the return spring 135 in contact with the Slips 134 are kept to an uncontrolled To prevent wandering of the disc. This can be the inner Disc also provided with a stepped annular shoulder be on which the return spring is seated. With the selection the thickness of the first shim 54 and the top mentioned outer disc and the inner disc and with the second shim 57 so the way 62, the Residual air gap 60 and the maximum valve lift set become.

While the two preceding embodiments a Guide stub 39 'and 139, which in a relatively small end face 40 of the anchor ended, is now according to the embodiment of Figure 4, this area 241 significantly enlarged by the guide piece 239 for Side of the first dial 54 a plate-like Widening 63 has. Through this now available standing larger area arises at the approach of the Ankers to the shim 54 a squish flow with much more effective than in the previous example, so that the impact of the anchor on the dial at the end his possible way is even more attenuated and accordingly the rebound impulse, for further swinging would be significantly reduced. Also at In this embodiment, the return spring 235 as Cylinder spring formed analogous to the embodiment according to FIG. 3.

In a modification to the embodiment of Figure 4 is in Figure 5, the return spring 335 is no longer between the Anchor and the first shim 54 is arranged but between a spring plate 70, on which the closing spring 31 seated and the stop ring 26. The stop ring 26 is designed as inserted into an annular groove 71 ring, wherein between the stop ring and the axial boundary of Ring groove 71 a game 72 is provided. This game is in the magnitude of the path 62 between armature 28 and Shim 54. The return spring 335 extends while the length of a federal 73, which is attached to the annular groove 71 connects to the side of the closing spring out and the Edition of the spring plate 70 forms.

In this embodiment, the armature leads as in the above embodiment, a stroke over the length 62 and then back to the stop again 26 arrive, as in Figure 5 in the current position is shown. Subsequently, the armature 28 together with the Stop ring 26 under the action of the return spring 335 in the shown rest position of the anchor bolt 27 to the first adjustment plate 54 and takes there a defined Position guaranteeing that e.g. at one after one short pre-injection taking place main injection time is determined geometrically for the opening stroke. The game 72 allows the sliding movement of the anchor on his way 62nd

The spring 335 can also be dispensed with entirely, if of it is assumed that by the intrinsic weight of the armature of this always the lower position at the first Shim is reached. Furthermore supports a Residual magnetic force between armature and shim 54 the Fixing the anchor in contact with the adjusting washer.

Claims (9)

1. Solenoid valve (30) for controlling an injection valve of a fuel injection device having a valve needle whose opening enclosing is controlled by a solenoid valve which has an electromagnet (29) with a magnet pole (61), an armature (28) which is arranged in a space filled with fuel, and a valve element (25) which is moved with the armature and on which a valve closing spring (31) acts in the closing direction and which interacts with a valve seat (24), the armature being capable of being displaced in relation to an intermediate part (27) - which is connected to the valve closing element, is embodied as a bolt (27) and is guided in a sliding fashion in a sliding element which is arranged fixedly in the solenoid valve - and away from a pole-end stop on the bolt in the closing direction of the valve element (25) as its inert mass acts counter to a restoring force, and a damping device which interacts with the armature and its fixed part, operates as fuel is expelled and with which reverberation of the armature (28) during its dynamic displacement can be damped, characterized in that the fixed part of the damping device is a part which is mounted in front of the sliding element and is preferably embodied as a washer and on which the armature comes to rest with an end side during its dynamic displacement.
2. Solenoid valve according to Claim 1, characterized in that the armature can be displaced, on the intermediate part which is embodied as bolt (27), away from a pole-end stop on the bolt which is guided in a sliding fashion in a sliding element which is arranged fixedly in the solenoid valve.
3. Solenoid valve according to Claim 2, characterized in that the armature is embodied as an anchor plate which interacts with the magnet pole (61), said armature having a first end side which points to the magnet pole (61) of the electromagnet, and a second end side which points to the fixed part and which forms the damping device with the fixed part.
4. Solenoid valve according to Claim 3, characterized in that the armature has a stem which connects the armature plate to a stop part whose end side forms, as a second end side of the armature, a planar face, a hydraulically effective, damping squeezing gap being formed between said planar face and the planar, fixed part as they approach one another.
5. Solenoid valve according to Claim 4, characterized in that the stop part widens in a flange-like fashion starting from the diameter of the stem.
6. Solenoid valve according to one of the preceding claims, characterized in that the valve seat of the solenoid valve is arranged fixedly in an injection valve housing, in that the electromagnet of the solenoid valve is arranged in a housing which is permanently clamped into the injection valve housing, the sliding element having a stop against which a valve-element-end stop part of the bolt comes to rest during the maximum opening stroke of the valve element, and an adjustment washer is mounted in front of the sliding element, the thickness of which makes it possible to adjust a residual air gap which comes about between the armature and magnet pole (61) of the electromagnet if the valve element of the solenoid valve is in the open position when the electromagnet is excited.
7. Solenoid valve according to Claim 6, characterized in that the adjustment washer at the same time forms the fixed part of the damping device.
8. Solenoid valve according to Claim 7, characterized in that, apart from the adjustment washer, an additional washer, which is used as a fixed part and for adjusting the maximum displacement distance of the armature in the closing direction of the valve on the bolt is clamped to the solenoid valve housing and the injection valve housing.
9. Solenoid valve according to one of Claims 6 to 8, characterized in that the adjustment washer and/or the additional washer are clamped in fixedly by the solenoid valve with the injection valve housing as they lie between a flange of the sliding element and the housing of the solenoid valve, and in that, in order to adjust the position of the sliding element and thus to adjust the maximum stroke of the valve element, a second adjustment washer is clamped in between the injection valve housing and the flange of the sliding element.

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