EP1266135B1 - Electrovalve for controlling an injection valve in an internal combustion engine - Google Patents

Abstract

The invention relates to an electrovalve which is used to control an injection valve in a combustion engine. The inventive electrovalve comprises an electromagnet (29), a moveable armature consisting of a plate (28) and a pin (27), in addition to a control valve member (25) which is moved with the armature and cooperates with a valve seat (24) in order to open and close the fuel discharge line (17) of a control pressure chamber (14) of the injection valve (1). The armature plate (28) is mounted in such a way that it can be slidingly displaced on the armature pin (27) as a result of the inert mass thereof in the direction in which the control valve member (25) closes, counter to the tension force of a restoring spring acting upon the armature plate (28). The maximum slide path of the armature plate (28) can be easily adjusted using a final controlling element which is provided on the armature plate. Said controlling element is disposed on a section (42) of said plate (28) opposite the electromagnet (42) and can be moved in relation to the front surface (41) of the armature plate facing the electromagnet in the direction in which the armature plate can slide.

Description

State of the art

The invention relates to a solenoid valve for controlling a Injection valve of an internal combustion engine according to the generic term of claim 1.

Such a known, for example from DE 197 08 104 A1 Solenoid valve is used to control the fuel pressure in the Control pressure chamber of an injection valve, for example in Injector of a common rail injection system, related. about the fuel pressure in the control pressure chamber becomes the movement of a Valve piston controlled with an injection opening of the injection valve is opened or closed. The known Solenoid valve has one arranged in a housing part Electromagnets, a movable armature and a moved with the anchor, by a closing spring in the closing direction acted upon control valve member with a Valve seat of the solenoid valve interacts and thus the fuel outflow controls from the control pressure chamber. A friend The disadvantage of solenoid valves is the so-called anchor bounce. When the magnet is switched off, the armature becomes and with it the control valve member from the closing spring of the solenoid valve accelerated toward the valve seat to a fuel drain channel from the control pressure chamber. The impact the control valve member on the valve seat can be a disadvantage Swinging and / or bouncing of the control valve member on the valve seat result in the control of the injection process is affected. In the case of DE 197 08 104 A1 known solenoid valve, the armature is therefore in two parts with an anchor bolt and one on the anchor bolt slidably mounted anchor plate executed so that the anchor plate upon impact of the control valve member on the valve seat against the resilience of a return spring advanced. The return spring then conveys the anchor plate in their starting position on a stop part back of the anchor bolt. Thanks to the two-part design of the anchor becomes the effectively braked mass and thus the kinetic energy of the bouncing on the armature hitting the valve seat is reduced, however the anchor plate after closing the solenoid valve on the Swing the anchor bolt disadvantageously.

Since the solenoid valve is only activated again to a defined one Injection quantity results when the anchor plate is not more resonates, measures are required to reduce the ringing to reduce the anchor plate. This is particularly so to show short time intervals between for example, a pre and main injection is required. To solve this problem, the state of the art Technology a damping device, which a fixed Part and a part moved with the anchor plate. The stationary part is formed by an overstroke stop, which limits the maximum path length around which the anchor plate can move on the anchor bolt. The mobile Part is by a fixed part facing Projection of the anchor plate is formed.

The overstroke can be through the front of one of the anchor bolts leading, stationary in the housing of the solenoid valve clamped slider or by a the slider upstream part, for example an annular disc become. When the anchor plate approaches the overstroke arises between the facing end faces the anchor plate and the overstroke stop are hydraulic Damping space. The contained in the damping room Fuel generates a force equivalent to the movement of the anchor plate counteracts, so that the swinging of the anchor plate is strongly dampened.

The problem with the known solenoid valves is the exact one Setting the maximum glide path, which is the anchor plate should be available on the anchor bolt. The maximum Glide path, also called overstroke, is replaced by replacement the over lift disc, additional spacers or Grinding of the overstroke stop set. These solutions because they are a gradual setting require, complex and difficult to automate and extend the cycle times in production.

Advantages of the invention

The solenoid valve according to the invention with the characteristic Features of claim 1 avoids that in the prior art disadvantages. By arranging one on one section of the armature plate facing away from the electromagnet arranged actuator which is relative to that of the electromagnet facing end of the anchor plate in the sliding direction the anchor plate is adjustable is advantageous achieved that the maximum sliding path of the anchor plate on the Anchor bolt can be adjusted in a very simple manner, without parts being replaced or sanded several times have to. A multi-step setting process eliminated. The proposed solution is in particular one automated line production can be used cost-effectively.

Advantageous refinements and developments of the invention are covered by those in the subclaims Features.

For example, the damping device can advantageously be a hydraulic one Damping space between one end of the Actuator and one of the front of the actuator facing Face of the stationary in the housing of the solenoid valve fixed part of the damping device is formed become. The actuator can at its the fixed part facing end face an axial through opening Have implementation of the anchor bolt.

It is particularly advantageous to have the actuator on the anchor plate to be arranged adjustable via a thread. Go berserk the actuator with the anchor plate fixed or by turning the anchor plate with the actuator fixed, the maximum Sliding path of the anchor plate on the anchor bolt in easier Way to be set precisely.

The actuator is preferably one with an internal thread provided screw member is formed on a penetrated by the anchor bolt and with an external thread provided section of the anchor plate is screwed.

The accuracy of the setting results from the Thread. The axial adjustment of the Actuator with respect to that facing the electromagnet Face of the anchor plate with one full turn of the Actuator designed smaller than half a millimeter. The very flat thread pitch advantageously results in a Self-locking of the thread, so that the actuator in its End position is fixed. In addition, it can be provided that the actuator in the set position on the anchor plate can be locked.

In a particularly easy to assemble embodiment it is provided that the return spring with a End in the housing of the solenoid valve and with its other end supported on the actuator.

drawings

Fig. 1 einen Querschnitt durch den oberen Teil eines aus dem Stand der Technik bekannten Kraftstoffeinspritzventils mit einem Magnetventil,

Fig. 2 einen Ausschnitt aus einem Querschnitt durch das erfindungsgemäße Magnetventil mit dem Stellglied,

Fig. 3 einen Ausschnitt aus einem Querschnitt durch das erfindungsgemäße Magnetventil nach einem zweiten Ausführungsbeispiel.

Exemplary embodiments of the invention are illustrated in the drawings and are explained in the description below. It shows

1 shows a cross section through the upper part of a fuel injection valve with a solenoid valve known from the prior art,

2 shows a section of a cross section through the solenoid valve according to the invention with the actuator,

Fig. 3 shows a detail from a cross section through the solenoid valve according to the invention according to a second embodiment.

Description of the embodiments

Fig. 1 shows the upper part of a from the prior art known fuel injection valve 1, which for use is determined in a fuel injection system with a High-pressure fuel storage is equipped by a High pressure feed pump continuously with high pressure fuel is supplied. The fuel injector 1 shown has a valve housing 4 with a longitudinal bore 5 in which a valve piston 6 is arranged with one end on an arranged in a nozzle body, not shown Valve needle acts. The valve needle is in a pressure chamber arranged, via a pressure bore 8 with high pressure standing fuel is supplied. With an opening stroke movement of the valve piston 6, the valve needle through the constantly high pressure fuel acting on a pressure shoulder of the valve needle in the pressure chamber against the closing force of one Spring raised. Through one then connected to the pressure chamber Injection opening is used to inject the fuel the combustion chamber of the internal combustion engine. By lowering the valve piston 6 the valve needle in the closing direction in the Injector valve seat pressed and the injection process completed.

As can be seen in Fig. 1, the valve piston 6 is on its end facing away from the valve needle in a cylinder bore 11 out, which is introduced into a valve piece 12 which is inserted into the valve housing 4. In the cylinder bore 11, the end face 13 of the Valve piston 6 a control pressure chamber 14, which has a Inlet channel connected to a high-pressure fuel connection is. The inlet channel is essentially made up of three parts. A radially through the wall of the valve piece 12 leading Bore, the inner walls of which are part of their length form an inlet throttle 15, with one the valve piece annular space 16 surrounding the circumference is permanently connected, which annulus in turn via one in the inlet channel inserted fuel filter in constant connection with the high-pressure fuel connection in the valve housing 4 screw-in connector 9 stands. The annular space 16 is sealed to the longitudinal bore 5 via a sealing ring 39. Via the inlet throttle 15, the control pressure chamber 14 is in the High fuel pressure prevailing high fuel pressure exposed. Coaxial to the valve piston 6 branches out of the Control pressure chamber 14 a bore extending in the valve piece 12 from that provided with a discharge throttle 18 Fuel drain channel 17 forms the in a relief chamber 19 opens out with a low-pressure fuel connection 10 is connected, which in turn in no further shown way with a fuel return of the injection valve 1 is connected. The outlet of the fuel drain channel 17 from the valve piece 12 takes place in the area of a conically countersunk part 21 of the outer Face of the valve piece 12. The valve piece 12 is fixed in a flange area 22 via a screw member 23 clamped with the valve housing 4.

A valve seat 24 is formed in the conical part 21, with which a control valve member 25 of the injection valve controlling solenoid valve 30 cooperates. The control valve member 25 is in shape with a two-part anchor an anchor bolt 27 and an anchor plate 28 coupled, which armature with an electromagnet 29 of the solenoid valve 30 works together. The solenoid valve 30 includes the electromagnet surrounding housing part 60 that with the valve housing 4 firmly connected via screwable connecting means 7 is. In the known solenoid valve, the armature plate 28 under the influence of their inertial mass against the preload a return spring 35 dynamically displaceable on the anchor bolt 27 stored and is at rest by this return spring against one on the anchor bolt in an annular groove 49 fixed stop part 26 pressed. With its other end the return spring 35 is fixed to the housing Flange 32 of a slide 34 guiding the anchor bolt 27 from that with this flange between one on the valve piece 12 placed spacer 38 and the screw member 23 is firmly clamped in the valve housing. The anchor bolt 27 and with it the armature disk 28 and that with the anchor bolt coupled control valve member 25 are constantly by themselves Supporting closing spring 31 in the closing direction acts so that the control valve member 25 normally is in the closed position on the valve seat 24. When excited of the electromagnet is the armature plate 28 and the stop part 26 also the anchor bolt 27 to the electromagnet Moved, whereby the drain channel 17 to the relief space 19 is opened. Between the control valve member 25 and the anchor plate 28 there is an annular shoulder 33 on the anchor bolt 27, when the electromagnet is excited on the flange 32 stops and so the opening stroke of the control valve member 25th limited. The setting between the opening stroke is used the flange 32 and the valve piece 12 arranged spacer 38th

The opening and closing of the injection valve is as follows described controlled by the solenoid valve 30. The Anchor bolt 27 is constantly in through the closing spring 31 Closing direction applied, so that the control valve member 25 when the electromagnet is not energized in the closed position on Valve seat 24 abuts and the control pressure chamber 14 to the relief side 19 is closed so that there over the inlet channel very quickly builds up the high pressure that is also present in the high-pressure fuel reservoir. Over the area the end face 13 generates the pressure in the control pressure chamber 14 a closing force on the valve piston 6 and thus in Connected valve needle that is larger than the other in the opening direction as a result of the pending High pressure forces. If the control pressure chamber 14 by opening the solenoid valve to the relief side 19 opened, the pressure builds up in the small volume of the Control pressure chamber 14 very quickly, since this via the inlet throttle 15 is decoupled from the high pressure side. Consequently predominates on the valve needle in the opening direction force acting on the valve needle High fuel pressure so that the valve needle is up moves and the at least one injection opening Injection is opened. However, the solenoid valve closes 30 the fuel drain channel 17, the pressure in the control pressure chamber 14 through the one flowing in via the inlet channel 15 Fuel can be rebuilt so that the original Closing force is applied and the valve needle of the fuel injector closes.

When the solenoid valve closes, the closing spring 31 presses the anchor bolt 27 with the control valve member 25 abruptly against the valve seat 24. An adverse bounce or The control valve member oscillates because: the impact of the anchor bolt on the valve seat is elastic Deformation of the same causes what as energy storage acts, with part of the energy in turn on the control valve member is transmitted, which then together with the anchor bolt bounces off the valve seat 24. The known one shown in FIG Solenoid valve therefore uses a two-part armature with an anchor plate 28 decoupled from the anchor bolt 27. In this way, the total on the valve seat reduce the impact mass, but the anchor plate can 28 reverberate in a disadvantageous manner. Therefore, a arranged between the anchor plate 28 and the sliding sleeve 34 Over stroke stop related, for example in the form of a formed with a recessed disc part can be. The overstroke can also by the Anchor plate 28 facing end face of the slider is formed become. The spacer 38, the slider 34 and the Overstroke stops are fixed in place in the solenoid valve housing. The overstroke limit limits the maximum possible Displacement of the anchor plate 28 on the anchor bolt 27. Das Raising of the anchor plate 28 is between the overstroke and the anchor plate 28 formed hydraulic Damping space reduced and the anchor plate 28 arrives faster back to their starting position on the stop part 26 back. The setting of the overtravel respectively the maximum sliding path of the anchor plate 28 on the anchor bolt However, 27 is quite complex and is done by Replacing spacers or grinding the slider.

2 is a first embodiment of the invention shown. The same parts have the same reference numbers Mistake. As can be seen, uses the invention Solenoid valve has an armature plate 28 on its electromagnet 29 facing away from an axially adjustable actuator 50 is arranged. For setting the maximum glide path the anchor plate 28 may be relative to the actuator 50 the end face 41 of the armature plate facing the electromagnet 28 can be adjusted in the sliding direction of the anchor plate 28. Various embodiments are possible for this. The Actuator 50 can be a sliding bushing, for example. In is the preferred embodiment shown here the actuator 50, however, on the anchor plate 28 via a thread arranged adjustable and has the sliding sleeve on it 34 facing end face 51 an axial through opening 53 for carrying out the anchor bolt 27. The actuator 50 is provided with an internal thread 46 Screw member formed on one of the anchor bolts 27 penetrated and provided with an external thread 45 Section 42 of the anchor plate 28 is screwed on, which Section 42 a nozzle protruding toward the sliding sleeve 34 the anchor plate 28 forms. In the left part of Fig. 2 that is Actuator shown in an initial position in which it is up is screwed to the stop on the connecting piece 42. For setting the maximum sliding path of the anchor plate 28 is Actuator in the position shown in the right part of FIG. 2 screwed. This can be done so that the Actuator 50 initially so far from the nozzle 42 of the anchor plate 28 is unscrewed until its end face 51st abuts on the end face 52 of the slider 34. Subsequently it is again a defined distance on the nozzle 42 screwed on, the desired overtravel between the End face 51 of the actuator 50 and the end face 52 of the Slider 34 depending on the thread pitch exactly is set. Optionally, the actuator 50 can also be fixed are and the anchor plate 28 are rotated until the correct overtravel is set. Preferably that Screw thread of the actuator has a small thread pitch on. In a preferred embodiment the axial displacement of the actuator 50 with respect to the Face 41 of the anchor plate 28 at a full revolution 0.25 millimeters. With the special thread M7 x 0.25 (according to DIN 134 T1.11 (12.86)) can then, for example, an overtravel distance of approx. 15 µm by rotating the actuator by approx. 21 ° can be set. Due to the flat thread pitch is from a self-locking of the thread to go out, so that Actuator 50 is not adjusted over time. Possibly can also be provided locking means. For this For example, UV-curable locking agents can be used after setting the overtravel by means of be cured with a UV lamp. As in the right part of Fig. 2 can be seen, forms the end face 51 of the actuator 50 and that facing the end face 51 of the actuator Front 52 of the stationary sliding sleeve 34 between them hydraulic damping chamber through which a reverberation the anchor plate 28 is damped.

The return spring 35 is supported with one end on the Flange 32 of the slider 34 and with its other end the side 43 of the anchor plate facing away from the end face 41 28 and surrounds the actuator 50, which is therefore only is difficult to access. A particularly advantageous embodiment in which the actuator 50 is more accessible is shown in Fig. 3. In contrast to that in Fig. 2 shows the actuator 50 in a lateral extension of its facing the slider 34 Front 51 on a circumferential collar 55 on which the return spring 35 facing away from the slider 34 End supports. The left side in Fig. 3 shows the Start position, the right side the set end position. As can be seen, the actuator 50 in FIG. 3 not surrounded by the return spring 35 and is therefore for the Adjustment process more accessible. So tools can be on the Sides of the actuator are better positioned. Also in this Embodiment can optionally by rotating the anchor plate with the actuator held or by rotation of the actuator with the anchor plate held in place the maximum Sliding path of the anchor plate 28 on the anchor bolt 27 is precisely adjusted become.

Claims (8)

1. Solenoid valve for controlling an injection valve of an internal combustion engine, having an electromagnet (29), a movable armature with armature plate (28) and armature pin (27), and a control valve element (25) moved by the armature and interacting with a valve seat (24) in order to open and close a fuel discharge channel (17) of a control pressure chamber (14) of the injection valve (1), which armature plate (28), under the action of its inertial mass, is mounted such that it can be displaced in a sliding manner on the armature pin (27) in the closing direction of the control valve element (25) counter to the stressing force of a return spring (35) acting on the armature plate (28), and having a hydraulic damping device, with which post-pulse oscillation of the armature plate (28) during its dynamic displacement on the armature pin (27) can be damped, which damping device comprises a stationary part (34) and a part (15) moved with the armature plate (28), characterized in that the part (50) moved with the armature plate is formed by an actuating element which is arranged on a section (42) of the armature plate (28) that faces away from the electromagnet (29) and, in order to adjust the maximum sliding travel of the armature plate (28) relative to an end (41) of the armature plate that faces the electromagnet, can be adjusted in the sliding direction of the armature plate (28).
2. Solenoid valve according to Claim 1, characterized in that one end (51) of the actuating element (50) and one end (52) facing the end (51) of the actuating element and belonging to the part (34) of the damping device that is fixed so as to be stationary in the housing (60) of the solenoid valve (30) between them form a hydraulic damping chamber.
3. Solenoid valve according to Claim 1 or 2, characterized in that, at its end (52) facing the stationary part (34), the actuating element (50) has an axial through-opening (53) for the armature pin (27) to be led through.
4. Solenoid valve according to one of Claims 1 to 3, characterized in that the actuating element (50) is arranged on the armature plate (28) such that it can be adjusted via a thread.
5. Solenoid valve according to Claim 4, characterized in that the actuating element (15) is formed as a screw element provided with an internal thread (46) which is screwed onto a section (42) of the armature plate (28) which is penetrated by the armature pin (27) and provided with an external thread (45).
6. Solenoid valve according to either of Claims 4 and 5, characterized in that, during a complete revolution of the actuating element (50), the axial displacement travel of the actuating element (50) in relation to the end (41) of the armature plate (28) that faces the electromagnet (29) is preferably less than half a millimetre.
7. Solenoid valve according to one of Claims 1 to 6, characterized in that the actuating element (50) can be locked in the set position on the armature plate (28).
8. Solenoid valve according to one of Claims 1 to 7, characterized in that the return spring (35) is supported with one end in the housing (60) of the solenoid valve (30) and with its other end on the actuating element (50). (Fig. 3).

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