WO2019141585A1

WO2019141585A1 - Electromagnetic switching valve

Info

Publication number: WO2019141585A1
Application number: PCT/EP2019/050567
Authority: WO
Inventors: Matthias Bleeck; Dmitriy KOGAN; Sven Müller; Florian Seidl
Original assignee: Cpt Group Gmbh
Priority date: 2018-01-19
Filing date: 2019-01-10
Publication date: 2019-07-25
Also published as: DE102018200848A1

Abstract

The invention relates to an electromagnetic switching valve (10) for a fuel injection system, wherein a movable armature (24) moves a closing element (20); a movement-limiting stop (34) is provided, which limits movement of the armature (24); an armature surface (54) and a stop surface (50) are designed in such a way that the armature surface and the stop surface hit each other merely in at least one linear contact region (56) in the event of contact.

Description

description

Electromagnetic switching valve

The invention relates to an electromagnetic switching valve for a fuel injection system of an internal combustion engine.

In fuel injection systems, combustion chambers becomes a

Internal combustion engine fuel is usually provided with a high pressure, the pressure is for example in Benin internal combustion engines in a range of 150 bar to 400 bar and in diesel engines in a range of 1500 bar to 3000 bar. The high pressure in the respective fuel is generated by a high-pressure fuel pump. The higher the pressure that can be generated in the respective fuel, the lower are emissions that occur during combustion of the fuel in combustion chambers, which is particularly advantageous in the background that a reduction of

Emissions is increasingly desired.

To the fuel high-pressure pump for applying the force material with high pressure metered to deliver the fuel, a controllable inlet valve is usually provided on the high-pressure fuel pump.

Frequently fast-switching solenoid valves for controlling the mass flow of the fuel in the force high-pressure pump are used in this, which are designed as electromagnetic tables switching valves. These have an actuator region and a valve region, wherein in the Ven tilbereich a closing element cooperates with a valve seat to close the switching valve. The actuator region ensures that the closing element can be moved between a closed position and an open position. This is one movable magnetic component, the so-called anchor before seen, which is coupled to the closing element and entrains the closing element in a movement.

The armature strikes to limit its movement in the operation of the electromagnetic switching valve at each actuation of the switching valve on a movement limit stop and is thereby braked. Due to the braking movement of the armature and the impact, a pulse and thus a structure-borne noise are generated in the high-pressure fuel pump.

So far, the problem of noise in the From braking phase of the armature on the movement limit stop is solved by consuming electrical control profiles, in which a force pulse is initiated by the actuator shortly before the impact in the opposite direction.

The object of the invention is to provide a simplified electromag netic switching valve, in which a Geräu development can be reduced during operation to a minimum.

This object is achieved with an electromagnetic switching valve with the feature combination of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

An electromagnetic switching valve for a fuel injection system of an internal combustion engine includes a closing member for closing the switching valve in a closing position and a movable armature coupled to the shooting member for moving the closing member along a moving axis between the closing position and an opening position. Furthermore, the switching valve has a Bewegungsbegrenzungsan- strike, which limits a movement of the anchor. An on keroberfläche of the armature and a stop surface of the movement limit stop are formed such that they meet in contact only at least one line-shaped contact area.

The armature surface and the abutment surface are the two areas of armature and movement limit stop, which come in contact with each other during operation of the electromagnetic switching valve, especially when braking the armature. If the contact area of these two surfaces is kept to a minimum, namely in the form of a line, only in this li nienförmigen contact area creates a noise that can be derived by the volume of the movement limit stop. As a result, a damping of structure-borne noise can be achieved.

The anchor surface and / or the impact surface preferably has a surface structure which provides the linear contact area upon contact of the armature surface and the stop surface.

Both the anchor itself and the Bewegungsbegrenzungsan impact can have a corresponding surface structure. It is also possible that only one of the two components has the surface structure which provides the linear contact area.

In an advantageous embodiment, the surface structure is elastically deformable. As a result, the Oberflä chenstruktur spring properties, which contribute to a damping of structure-borne noise.

Preferably, the surface structure is formed of an elastic material and has in a direction perpendicular to the movement Transmission axis of the closing element arranged cross-section of a tooth structure, in particular an irregular tooth structure on. The serration structure ensures that the Oberflä chenstruktur can plastically deform when a collision of the armature and the movement limit stop, and thus dampens the clash of anchor and Be movement limit stop.

Preferably, the surface structure is formed of an elastic material and convex out in a cross-section arranged perpendicular to the axis of movement of the closing element. In this case, the convex design may have a smooth upper surface structure, but it is also possible that the convex configuration is formed combined with the tooth structure. Again, a plastic deformation of the upper surface structure occurs at the meeting of the Bewegungsbegren tion stop and the armature, so that the impact can be damped.

In an alternative embodiment, the surface structure is formed of an elastic material and formed in a direction perpendicular to the axis of movement of the closing element arranged cross-section wedge-shaped.

In the described embodiments of the surface structure, the surface structure is formed of an elastic material which provides spring and thus damping properties ma material side.

By changing the basic cross section of the surface structure, for example as a serrated structure, convex or wedge-shaped, a spring rate and thus also the damping caused by the surface structure can be adjusted from the design side. Through the particular shape can be achieved be that a self-building up by the braking force counterforce increases more slowly and thus produces less noise.

In an alternative embodiment, the anchor surface and / or the abutment surface are bundled from a filament bundle.

In this case, the filament bundle may be formed for example from a me-metallic wire or plastic strands. Because there are gaps in a filament bundle, this filament bundle can yield under a low mechanical resistance when it encounters a moving element, whereby the moving element is decelerated. Thereafter, the filament bundle springs back into its original shape.

In this case, the individual filaments provide a plurality of line-shaped contact areas, so that a further design of the surface in the form of a special surface structure can be dispensed with.

Advantageously, the movement limiting stopper is formed as a ring-shaped disc, which is arranged as a separate component in a guide portion of a housing part of the electromagnetic switching valve for guiding the armature in its movement. Therefore, the anchor strikes for braking in a separately formed annular disc, which either has the surface structure described above or is formed directly as a filament bundle.

Preferably, the annular disc has hydraulic equalization grooves. The compensation grooves are formed on the abutment surface of the disc and avoid a hydraulic gluing of anchor and disc after their contact on impact.

Advantageous embodiments of the invention will be explained in more detail with reference to the accompanying drawings. It shows:

Fig. 1 is a schematic sectional view through a

electromagnetic switching valve, in which a

Closing element is moved by an armature, wherein the armature is braked in its movement by a Bewegungsbe limit stop;

Fig. 2 is a perspective view of the Bewegungsbe limiting stop of Figure 1, which is designed as an annular disc.

Fig. 3 is a further perspective view of the movement limitation stop BEWE according to FIG. 2;

Fig. 4 is a cross-sectional view of the Bewegungsbegren

latches of Fig. 2 and Fig. 3 in a first embodiment;

Fig. 5 is a cross-sectional view of the Bewegungsbegren

clamping stop of Figure 2 and Figure 3 in a second embodiment.

Fig. 6 is a cross-sectional view of the Bewegungsbegren

latches of Fig. 2 and Fig. 3 in a third embodiment; and

Fig. 7 is a cross-sectional view of the Bewegungsbegren

2 and 3 in a fourth embodiment. 1 shows a schematic sectional illustration of an electromagnetic switching valve 10, which is arranged as an inlet valve 12 on a high-pressure fuel pump 14 of an internal combustion engine. The electromagnetic switching valve 10 has a valve region 16 and an actuator region 18, wherein in the valve region 16, a shooting element 20 interacts with a valve seat 22 to close the switching valve 10 in a closed position. If the closing element 20 is lifted from the valve seat 22, the switching valve 10 is in its Publ voltage position.

The closing element 20 is thereby moved by the actuator region 18 along a movement axis 23. For this purpose, the closing element 20 is coupled to a movable armature 24. In addition to the armature 24, the actuator region 18 further comprises a fixed pole piece 26 and a coil 28.

If, during operation of the switching valve 10, the coil 28 is electrically energized, that is to say supplied with current, a magnetic field is produced which forms a magnetic circuit. Inside the magnetic circuit are the two relatively axially movable, magnetic components, namely the movable armature 24 and the fixed pole piece 26. These two components are spaced apart by a compression spring 30 to each other and are held apart by this compression spring 30. Due to the built-up magnetic field, a force is generated which pulls the pole piece 26 and the armature 24 toward each other and overcomes the spring force of the compression spring 30. As a result, the armature 24 is set in motion.

Since the armature 24 is coupled to the closing element 20, the armature 24 takes with its movement the closing element 20 with. In the present embodiment, the switching valve 10 is designed as a normally open switching valve 10, that is, the compression spring 30 holds in the de-energized state of the coil 28, the armature 24 at a distance from the pole piece 26 and thus the closing element 20 in its open position. Accordingly, if an electrical control of the coil 28 is turned off, the compression spring 30 presses the armature 24 directly or indirectly, for example via a coupling element 32, back into the open position.

The design of the electromagnetic switching valve 10 as a normally open switching valve 10 is only an exemplary embodiment, it is also possible to arrange the compression spring 30 accordingly different, so that the switching valve 10 is formed as a normally closed switching valve 10.

In the present embodiment, the armature 24 encounters in its movement in the direction of the opening position of the closing ßelementes 20 on a movement limit stop 34, which is formed in the present embodiment as a disc 36, a separate component in a housing part 38 of

Switching valve 10 forms, which forms a guide portion 40 for guiding the armature 24 during its movement. The loading movement limit stop 34, which is thus arranged in the static guide of the armature 24, brakes the downward movement of the armature 24. By the braking movement of the armature 24, a pulse and thereby a structure-borne noise in the fuel high-pressure pump 14 is generated.

The control of the let into the high-pressure fuel pump 14 fuel quantity via the electromagnetic switching valve 10 is as follows:

The fuel enters the high-pressure fuel pump 14 via an inlet 42 into the force. A pump piston 44 moves oscillating within a pressure chamber 46 of the high-pressure fuel pump 14. By a downward movement of the pump piston 44, the fuel is sucked from the inlet 42 into the pressure chamber 46 in an opening position of the closing element 20. During an upward movement of the pump piston 44, the closing element 20 initially remains in the open position, so that the fuel is fed back into the inlet 42. This is known as "reflux."

If now the fuel is not re-refluxed into the inlet 42, but in a high-pressure region 47, such as a rail promoted, the closing element 20 is brought by the actuator portion 18 during the upward movement of the pump piston 44 in its closed position. In the closed position of the switching valve 10, an inlet cross-section is closed. As a result, in the remaining upward movement of the pump piston 44, the fuel can be delivered via an outlet valve 48 in the high-pressure region 47.

If the delivery of the fuel in the high-pressure region 47 is terminated, the coil 28 is switched off again, and the closing element 20 returns together with the armature 24 in the starting position (opening position). In this case, the armature 24 beats for braking its movement, which has been induced by the spring force of the compression spring 30, in the Bewegungsbe limit stop 34 a.

The travel limit stop 34 is formed in the present embodiment as a separate annular disc 36 mounted below the armature 24 in an area below the static guide of the armature 24. The disc 36 has a defined thickness in the unloaded state, so that a defined position of the movement limiting stopper 34 is available in the starting position. The movement limit stop 34 is provided in the present embodiment as a separately formed disc 36, but it is also possible, the movement limit stop 34 directly in the guide portion 40, ie, integral with the housing part 38, form.

The Bewegungsbegren formed as an annular disc 36 tion stop 34 is shown in Fig. 2 and Fig. 3 each in a perspective view. The disc 36 has on a stop surface 50 hydraulic Ausgleichsnuten 52 which prevent hydraulic bonding between the Bewegungsbe limit stop 34 and the armature 24 in contact.

In order to further reduce the resulting structure-borne noise, which arises when striking the armature 24 on the movement limit stop 34, it is proposed that an anchor surface 54, which comes into contact with the abutment surface 50 at impact, and the abutment surface 50 in such a way Contact only on at least one line-shaped contact area 56 meet. As a result, acting impact forces can be dissipated and the resulting Kör perschall is reduced.

The armature surface 54 or the abutment surface 50 may each individually or both have a surface structure 58 which provides the linear contact region 56. Examples of this are shown in cross-sectional views through the disc 36 (position of the cross-section shown in Fig. 3) in Figs. 4 to 6 shown.

The disc 36 is in the first embodiment according to FIG. 4, the second embodiment according to FIG. 5 and the third embodiment according to FIG. 6 each made of an elastic Material 60 formed so that the surface structure 58 is each elastically deformable.

In the first embodiment, the surface structure 58 is formed as an irregular serration structure 62. When the armature 24 and the washer 36 come together, the serrated structure 62 deforms plastically, absorbing and damping impact forces. After the impact, the serrated structure 62 returns to its original shape. The disc 36 accordingly has spring properties and thus can dampen the impact.

A second embodiment is shown in Fig. 5, where the disc 36 is also formed of an elastic material 60 and has a convex shape 64. Alone by the convex shape 64 here is the disc 36 on the abutment surface 50 plastically deformable and can absorb the impact forces and dampen. It too returns to its original convex shape 64 after impact. The convex shape 64 may be combined with the serration structure 62 of the first embodiment.

In an alternative third embodiment, shown in FIG. 6, the disc 36 is wedge-shaped in cross section and accordingly has a wedge-shaped surface structure 58. The effect of the wedge-shaped surface structure 58 is corresponding to the surface structure 58 with the convex shape 64 of FIG. 5. The wedge-shaped surface structure 58 can also be combined with the tooth structure 62 from the first embodiment in FIG.

An alternative way of forming a linear contact area 56 between the stop surface 50 and on keroberfläche 54 is shown in the cross-sectional view of the disc 36 in Fig. 7 as a fourth embodiment. Here, the disc 36 is formed as a filament bundle 66 and has, for example, simple metallic wires or plastic strands, which form the filament bundle 66. The individual filaments of the filament bundle 66 are arranged such that automatically results in a surface structure 58, which provides a linear contact area 56 between stop surface 50 and anchor surface 54.

The surface structure 58 and the filament bundle 66 can be provided as a single component, namely, for example in the form of the ring-shaped disc 36, in the electromagnetic switching valve 10. However, it is also possible to provide these structures integral with the armature 24 itself or with the Ge housing part 38 in the guide portion 40. The advantage of this structure is that it can easily provide a resilient and damping structure that is provided for noise reduction.

Claims

claims

An electromagnetic switching valve (10) for a fuel injection system of an internal combustion engine, comprising: a closing member (20) for closing the switching valve (10) in a closing position;

a movable armature (24) for moving the

Closing element (20) along a movement axis (23) between the closed position and an opening position with the

Locking element (20) is coupled; and

a travel limit stop (34) that limits movement of the armature (24);

wherein an anchor surface (54) of the armature (24) and a stop surface (50) of the movement limit stop (34) are formed such that they meet at a contact only at least one line-shaped contact region (56) aufei.

2. Electromagnetic switching valve (10) according to claim 1, characterized in that the armature surface (54) and / or the abutment surface (54) has a surface structure (58), the line-shaped contact region (56) upon contact of armature surface (54). and stop surface (50).

3. Electromagnetic switching valve (10) according to claim 2, characterized in that the surface structure (58) is elastically deformable.

4. Electromagnetic switching valve (10) according to one of claims 2 or 3,

characterized in that the surface structure (58) of an elastic material (60) is formed and in a direction perpendicular to the movement axis (23) of the closing element (20) arranged cross-section a serration (62), in particular an irregular serration structure (62) ,

5. Electromagnetic switching valve (10) according to one of claims 2 to 4,

characterized in that the surface structure (58) of an elastic material (60) is formed and in a perpendicular to the movement axis (23) of the closing element (20) arranged cross-section convexly (64) is formed.

6. Electromagnetic switching valve (10) according to one of claims 2 to 4,

characterized in that the surface structure (58) of an elastic material (60) is formed and in a direction perpendicular to the movement axis (23) of the closing element (20) arranged cross-section is wedge-shaped.

7. An electromagnetic switching valve (10) according to any one of claims 1 to 3,

characterized in that the anchor surface (54) and / or the abutment surface (50) is formed from a filament bundle (66).

8. Electromagnetic switching valve (10) according to claim 7, characterized in that the filament bundle (66) is formed of me-metallic wire or plastic strands.

9. Electromagnetic switching valve (10) according to one of claims 1 to 8,

characterized in that the movement limit stop (34) is formed as an annular disc (36) which is arranged as a separate component in a guide portion of a housing part (38) of the electromagnetic switching valve (10) for guiding the armature (24) during its movement.

10. Electromagnetic switching valve (10) according to claim 9, characterized in that the annular disc (36) has hydraulic compensation grooves (52).