EP2901004B1 - Injection valve - Google Patents

Description

State of the art

The present invention relates to an injection valve for injecting a medium, in particular for injecting fuel into a combustion chamber. The injection process can be designed as a channel or direct injection.

State of the art are valves for the injection of gasoline with a valve needle, which is moved by an actuator, such as an electromagnet or piezo actuator, against a closing spring so that a desired amount of fuel is introduced directly targeted into the combustion chamber. In the present case, an injection valve is considered in which the armature is decoupled from the valve needle. When opening the injector, the armature should quickly release from the valve stop located on the lower stop (second stop), quickly overcome the Ankerfreiweg and open the valve quickly when hitting the top stop (first stop). If the energization of the valve is terminated, the valve needle closes again. The armature, after the valve needle closes the valve seat, continues to move until it encounters the lower limit stop. From the bottom stop, the anchor rebounds several times until it reaches its rest position again. The time it takes for the armature to return to the rest position is critical to the ability of the valve to rapidly eject successive injections with high accuracy. Usually, a crimp gap is formed at the lower stop, that is to say between magnet armature and the corresponding stop sleeve on the valve needle. In this nip the medium to be injected is squeezed, so that when closing the armature is damped and quickly returned to the rest position. However, the nip prevents rapid opening by stopping the movement dampens when opening. The nip must therefore be designed as a compromise so that the armature opens the valve sufficiently quickly, and is reset sufficiently quickly to the rest position.

DE19849210A1 shows a known injection valve.

Disclosure of the invention

The injector according to the invention with the features of claim 1 makes it possible to better dampen the armature and thus reset the armature after closing the injector faster than before in its rest position. At the same time, the damping is reduced according to the invention when opening the injection valve, so that the injection valve opens faster. In detail, there are thus the following advantages when opening the injection valve: The armature dissolves faster than before from the valve needle, whereby the dynamics of the valve is increased and thus the function is improved. The force required to open is reduced, which reduces the power consumption of the injector and thus the total energy consumption of the vehicle. As a result, the consumption of the vehicle decreases. When closing the injection valve, the following advantages result: The movement of the armature is attenuated more than previously. As a result, the magnet armature reaches its rest position earlier than before, as a result of which short successive injections can be discontinued with high repeat accuracy. With the injection valve according to the invention new injection strategies are possible, which allow combustion with less pollutant emissions and less consumption. The better damping when closing the injector reduces the noise that results from the momentum transfer of the armature to the valve needle. All of these advantages are achieved by an injection valve according to the invention, comprising a housing with at least one injection opening on an outlet side, a magnetic coil and a magnet armature linearly movable by the magnetic coil. Furthermore, the injection valve has a valve needle. This valve needle is used to open and close the at least one injection opening. The valve needle extends along a longitudinal axis and is linearly movable. In the magnet armature, a through hole is formed. The valve needle is in this through hole. The armature is linearly movable between a first and a second stop relative to the valve needle. This creates a two-mass system. The first stop is on a side facing away from the outlet formed of the armature. For example, the first stop is formed by a ring on the valve needle. The second stop is formed on an outlet-facing side of the magnet armature. According to the invention, the second stop is formed by a stop element and a counter element. At the second stop, the stop element and the counter element hit each other. For this purpose, the stop element on a stop surface. On the counter element one of the stop surface opposite counter surface is formed. The stop surface and the counter surface meet each other at the second stop. The stop element is designed to be elastic, so that an angle between the longitudinal axis and stop surface changes when striking counter surface and stop surface. In particular, it is provided that the stop surface is inclined before and after the contact of stop element and counter element to the counter element. As soon as counter element and stop element meet, the stop element is elastically deformed, so that the space between stop surface and counter surface decreases. Due to the elastic design of the stop element according to the invention, it is possible that the nip and the throttle flow between stop surface and mating surface to move when moving together and Voneinanderwegbewegen from stop surface and mating surface. As a result, the damping during opening and closing of the injection valve can be set very precisely.

The dependent claims show preferred developments of the invention.

The stop element is firmly connected to the valve needle. Accordingly, then the counter element is located on the armature. The counter element is an integral part of the magnet armature. In the simplest case, the counter surface is the side of the magnet armature facing the abutment surface. It is crucial that at least one of the two opposing surfaces is formed elastically on the second stop. This at least one elastic surface is referred to in the present application as a stop surface.

Preferably, the stop element is integrated in the valve needle.

Furthermore, it is preferably provided that the angle between the longitudinal axis and abutment surface is at least in places smaller than 90 ° without contact of abutment surface and counter surface. The angle is defined on the opposite surface facing the stop surface. This means that the angle of less than 90 ° defines that the stop surface is inclined towards the opposite surface. It is sufficient if the stop surface only in places has this inclination with the appropriate angle. During the abutment of the counter surface on the stop surface, the stop surface is deformed, so that the angle is increased.

When lifting stop surface and mating surface, so when opening the injector, the stop element relaxes again, so that the angle decreases again. Due to this design of the angle, it is possible that when opening the injector only a throttle flow, but no squish, dampens the movement of the armature. As soon as the mating surface and the abutment surface move away from each other slightly, the abutment element relaxes and the abutment surface thus tilts in the direction of the mating surface. As a result, stop surface and counter surface are then no longer parallel to each other and there is no nip. Only a throttle flow, namely the flow of the medium to be injected, which flows out of the area between the stop surface and counter surface, dampens the opening movement of the magnet armature.

When closing the injector stop surface and counter surface move towards each other. First, the abutment surface is inclined in the direction of the mating surface, so that a relatively large, filled with the medium space between abutment surface and mating surface is present. The movement is first damped by a throttle flow and as soon as the stop surface and counter surface meet, the stop surface is deformed, so that the stop surface is aligned parallel to the counter surface. This creates a nip for damping the movement of the magnet armature. The Damping effect thus increases with the decreasing distance between the stop surface and counter surface.

In particular, it is provided that the angle without the contact of abutment surface and mating surface is a maximum of 89.99 °, preferably a maximum of 89.85 °. As already described above, this angle does not have to be present over the entire stop surface.

Furthermore, it is preferably provided that the angle is elastically deformed by at least 0.01 °, preferably at least 0.15 °, by the abutment of counter surface and abutment surface. In a particularly preferred embodiment, the stop surface is deformed so far until stop surface and counter surface are aligned parallel to each other.

Furthermore, it is advantageous that the stop surface is divided into an inner portion and an outer portion. The inner portion is closer to the longitudinal axis than the outer portion. Particularly preferably, the stop surface is an annular surface around the valve needle. The inner portion is an inner annular surface. The outer portion is a further annular surface located outside the inner portion. The angle without the contact of abutment surface and counter surface is greater at the outer portion than at the inner portion. Preferably, it is provided that the stop surface tends towards the counter surface with increasing distance from the longitudinal axis.

Particularly preferably, it is provided that the inner portion is formed without the contact of the stop surface and counter surface parallel to the counter surface. Alternatively, the inner portion may be slightly inclined to the opposite surface or concave.

At the stop element, a side facing away from the opposite surface is referred to as outer surface. This outer surface should also be shaped accordingly, so that sufficient elasticity for deformation of the stop surface is given. Therefore, the outer surface is preferably inclined towards the counter element or at least locally concave. Alternatively, the outer surface may be partially parallel to the stop surface. It is also decisive that the stop element is formed as thin as possible, so that the stop surface can deform elastically.

In order to ensure the elastic deformability of the stop element and thus also the stop surface, grooves are preferably provided in the stop element. Particularly preferably, these grooves are formed completely circumferentially about the longitudinal axis.

The first stop, is preferably formed by a paragraph or by a ring on the valve needle.

Brief description of the drawings

Figur 1

ein erfindungsgemäßes Einspritzventil für alle Ausführungsbeispiele,

Figur 2

ein Detail des erfindungsgemäßen Einspritzventils gemäß einem ersten Ausführungsbeispiel,

Figur 3

ein weiteres Detail des erfindungsgemäßen Einspritzventils gemäß dem ersten Ausführungsbeispiel,

Figuren 4 bis 7

einen Bewegungsablauf am erfindungsgemäßen Einspritzventil gemäß dem ersten Ausführungsbeispiel,

Figur 8

das erfindungsgemäße Einspritzventil gemäß einem zweiten Ausführungsbeispiel,

Figur 9

das erfindungsgemäße Einspritzventil gemäß einem dritten Ausführungsbeispiel,

Figur 10

das erfindungsgemäße Einspritzventil gemäß einem vierten Ausführungsbeispiel,

Figur 11

das erfindungsgemäße Einspritzventil gemäß einem fünften Ausführungsbeispiel,

Figur 12

das erfindungsgemäße Einspritzventil gemäß einem sechsten Ausführungsbeispiel, und

Figur 13

das erfindungsgemäße Einspritzventil gemäß einem siebten Ausführungsbeispiel.

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. Showing:

FIG. 1

an inventive injection valve for all embodiments,

FIG. 2

a detail of the injection valve according to the invention according to a first embodiment,

FIG. 3

another detail of the injection valve according to the invention according to the first embodiment,

FIGS. 4 to 7

a movement sequence at the injection valve according to the invention according to the first embodiment,

FIG. 8

the injection valve according to the invention according to a second embodiment,

FIG. 9

the injection valve according to the invention according to a third embodiment,

FIG. 10

the injection valve according to the invention according to a fourth embodiment,

FIG. 11

the injection valve according to the invention according to a fifth embodiment,

FIG. 12

the injection valve according to the invention according to a sixth embodiment, and

FIG. 13

the injection valve according to the invention according to a seventh embodiment.

Embodiments of the invention

The following is based on the FIGS. 1 to 7 a first embodiment of the injection valve 1 explained. Identical or functionally identical components are provided with the same reference numerals in all embodiments.

FIG. 1 shows the general structure of the injection valve 1 for all embodiments. The injection valve 1 comprises a housing 2 with an injection opening 4 on an outlet side 3. The housing 2 carries a magnetic coil 5. Inside the housing 2, a valve needle 6 with a ball 7 is arranged along a longitudinal axis 15. The ball 7 forms with the housing 2 a valve seat for opening and closing the injection opening 4th

Furthermore, located in the housing 2, a magnet armature 8 which is connected to a spring cup 9. On a side facing away from the magnet armature 8, a ring 10 is fixedly arranged on the valve needle 6. This ring 10 forms a first stop for the magnet armature 8. On an outlet-facing side of the magnet armature 8 is a stop element 12. This stop element 12 forms together with the armature 5, a second stop.

Both the valve needle 6 and the magnet armature 8 are linearly movable along the longitudinal axis 15. The movement of the magnet armature 8 is limited by the first and second stop.

In the armature 8 more channels 16 are provided for the medium to be injected. Additionally or alternatively, the valve needle 6 may be formed hollow.

By means of a first spring 11, the valve needle 6 is loaded in the direction of the outlet side 3. A second spring 13 between the spring cup 9 and the stop element 12 also loads the magnet armature 8 in the direction of the outlet side 3.

By energizing the solenoid 5, the armature 8 is moved. The armature 8 takes over the first and second stop the valve needle 6 with. The distance between the two stops defines an anchor path 14.

FIG. 2 shows a detail of the injection valve 1 according to the first embodiment. It can be seen that the stop element 12 is made in one piece with a sleeve 20. The sleeve 20 is inserted on the valve needle 6 and is firmly connected to the valve needle 6. The armature 8 is at the same time designed as a so-called counter element 18.

A counter element 18 facing surface on the stop element 12 is referred to as a stop surface 17. The abutment surface 17 is located opposite the mating element 18 against a counter surface 19. A side facing away from the counter element 18 of the stop element 12 is referred to as the outer surface 21. The drawn angle α is defined between the abutment surface 17 and the longitudinal axis 15. The angle α is measured on the side of the abutment surface 17 facing the counter element 18.

The stop element 12 and thus also the stop surface 17 are elastically deformable. Upon impact of the counter element 18, so the armature 8, on the stop element 12, the stop element 12 is elastically deformed, so that the angle α increases.

FIG. 3 shows in detail the sleeve 20 and the stopper 12. The sleeve 20 and the stopper 12 have a longitudinal axis 15 coaxial through hole 28. In this through hole 28, the valve needle 6.

A first height 25 extends parallel to the longitudinal axis 15 from the upper end of the through hole 28 to the outer end of the abutment surface 17. The outer end of the abutment surface 17 is referred to as a tip 27. A second height 26 marks the extension of the stop element 12 parallel to the longitudinal axis 15. In the illustrated embodiment, the elasticity of the stop surface 17 is given by the fact that the two heights 25, 26 are greater than 0.

The FIGS. 4 to 7 show a sequence of movements when opening and closing the injector. FIG. 4 shows the idle state in which the magnetic coil 5 is not energized and the armature 8 only slightly rests on the stop element 12. Accordingly, the stop surface 17 is not deformed and the stop surface 17 is inclined α with the angle α smaller than 90 ° to the counter surface 19.

In the following figures, reference numeral 29 denotes a throttle flow of the medium to be injected. The dashed line of the stop element 12 shows the elastic deformation.

In FIG. 5 is pulled by the applied magnetic field at the magnetic coil 5 of the armature 8 in the direction of the inner pole, in the illustration shown upwards. The valve needle 6 remains in the valve seat until the armature 8 has overcome the Ankerfreiweg 14 and the valve needle 6 via the ring 10 (first stop) entrains. As long as there is a relative movement between armature 8 and valve needle 6, the throttle flow 29 is formed between magnet armature 8 and valve needle 6, that is to say between abutment surface 17 and mating surface 18. The throttle flow 29 between abutment surface 17 and mating surface 19 decreases with increasing distance, so that the Injector can open quickly. In FIG. 6 the current at the solenoid 5 is turned off, the magnetic field degrades. The valve needle 6 is located in the seat and the magnet armature 8 can continue its movement in the direction of the second stop on the stop element 12 coming from the first stop on the ring 10. The relative movement between the magnet armature 8 and the valve needle 6 results in the throttle flow 29 between the stop surface 17 and the counter surface 19 again. The throttle flow 29 increases with decreasing distance, so that the movement of the magnet armature 8 is increasingly damped. Meets the armature 8 on the Stop element 12, ie, the mating surface 19 presses on the stop surface 17, the stop element 12 is elastically deformed by the impact and the damping volume located between stop surface 17 and mating surface 19 becomes a nip. This state shows FIG. 7 , The movement of the armature 8 is thereby braked. Due to the elastic deformation of the stop element 12, the stop surface 17 is aligned plane-parallel to the counter surface 19, whereby the damping of the magnetic armature movement is maximized by the nip.

FIG. 8 shows a detail of the injection valve 1 according to a second embodiment. In the second embodiment, the stop surface 17 is divided into an inner portion 23 and an outer portion 24. The inner portion 23 is also without contact with the counter surface 19 perpendicular to the longitudinal axis 15 and thus also parallel to the counter surface 19, respectively. In the outer portion 24, the stop surface 17, the inclination with the angle α in the direction of the counter surface 19.

The outer surface 21 is partially parallel to the mating surface 19 and partially inclined to the mating surface 19 is formed. In particular, the outer surface 21 is inclined approximately in the region of the outer portion 24 towards the counter surface, so that here a sufficient elasticity of the stop element 12 is given.

FIG. 9 shows a detail of the injection valve 1 according to a third embodiment. In the third embodiment, the stop surface 17 is inclined both in the inner portion 23 and in the outer portion 24 in the direction of the counter surface 19. However, the inclination in the outer portion 24 is stronger, so that here the largest deformation of the stop element 12 occurs.

FIG. 10 shows a detail of the injection valve 1 according to a fourth embodiment. In the fourth embodiment, the stop surface 17 is just as in the third embodiment in the inner portion 23 and inclined in the outer portion 24 in the direction of the counter surface 19. The outer surface 21 is thereby greatly inclined away from the sleeve 20 in the direction of the counter surface 19. This results in particular in the outer area a very narrow stop element 12, which is correspondingly elastically deformable.

FIG. 11 shows a detail of the injection valve 1 according to a fifth embodiment. In the fifth embodiment, the stop surface 17 is arranged on the inner portion 23 parallel to the counter surface 19. Along the outer portion 24, the stop surface 17 is concave. The outer surface 21 of the stop element 12 is concave. This results in a relatively narrow stop element 12 with rounded transitions between the various inclinations, so that a reliable elasticity is ensured. The angle α is defined by the tangent to the concave configuration of the stop surface 17 in the outer portion 24 and the longitudinal axis 15th

FIG. 12 shows a detail of the injection valve 1 according to a sixth embodiment. In the sixth embodiment, there is a groove in the outer surface 21 of the stop element 12. This groove 22 is in particular formed circumferentially around the longitudinal axis 15. Through the groove 22, the stop element 12 is weakened accordingly, so that the desired elasticity is given.

FIG. 13 shows a part of the injection valve 1 according to a seventh embodiment. In the seventh embodiment, in turn, a groove 22 for adjusting the elasticity of the stop element 12 is shown. In the seventh embodiment, the groove 22 is in a plane parallel to the longitudinal axis 15 surface of the stop element 12. As a result, the groove 22 extends very close to the tip 27 and the stop surface 17, so that in this embodiment, not the entire stop element 12, but only an upper portion is deformed.

The various embodiments show possible geometries of the stop element 12. In the embodiments, the stop surfaces 17 are designed wedge-shaped in the rule, since the wedge shape is easy to dimension and manufacture. Of course, combinations of the illustrated embodiments are possible. So can the in FIG. 12 and 13 shown grooves 22 are used in appropriate depth and number in the other embodiments. Furthermore, it is possible in all embodiments, the outer surface 21 according to the Figures 9 . 10 and 11 adapt. The different angles and concave configurations the stop surface 17 of the different embodiments can be combined. Further possible are all other concave and convex shapes of the stop element 12, as long as the sufficient elasticity is ensured. Other cross-sectional shapes for the groove 22 are, for example, triangles or ellipses. Also, more than one groove 22 per stop member 12 is possible to adjust the stiffness accordingly. The embodiments show rotationally symmetrical, non-hollow valve needles 6. It is equally possible to apply the invention to hollow and / or non-rotationally symmetrical valve needles 6. Also, the stop surface 17 or the counter surface 19 does not have to be rotationally symmetrical. All embodiments shown, the stop surface 17 and the stop member 19 fixedly connected to the valve needle 6. Accordingly, the armature 6 is defined in the embodiments as a counter element 18 with mating surface 19. The mating surface 19 is in the simplest embodiment of the invention, a flat, rigid surface. Just as well, it is possible that the counter surface 19 has a certain inclination and elasticity.

Claims (9)

1. Injection valve (1) for injecting a medium, in particular for injecting fuel into a combustion chamber, comprising:

   - a housing (2) with at least one spray opening (4) on an outlet side (3),

   - a magnet coil (5),

   - a magnet armature (8) which can be moved linearly through the magnet coil (5),

   - a valve needle (6) which can be moved linearly along a longitudinal axis (15) and protrudes through the magnet armature (8) for opening and closing the spray opening (4),

   characterized
   in that the magnet armature (8) can be moved linearly with respect to the valve needle (6) between a first stop and a second stop,
   the second stop being formed by way of a stop element (12) which is connected fixedly to the valve needle (6) with a stop face (17) and the magnet armature (8) with a corresponding face (19) which lies opposite the stop face (17),
   the second stop being provided on that side of the magnet armature (8) which faces the outlet of the at least one spray opening (4), and
   the stop element (12) of the second stop being of elastic configuration, with the result that, when the corresponding face (19) comes into contact on the stop face (17), an angle (α) between the longitudinal axis (15) and the stop face (17) changes.
2. Injection valve according to Claim 1, characterized in that the angle (α) between the longitudinal axis (15) and the stop face (17) without contact of the stop face (17) and the corresponding face (19) is less than 90° at least in places, the angle (α) being defined on that side of the stop face (17) which faces the corresponding face (19).
3. Injection valve according to Claim 2, characterized in that the angle (α) without the contact of the stop face (17) and the corresponding face (19) is at most 89.99°, preferably at most 89.85°.
4. Injection valve according to one of the preceding claims, characterized in that the angle (α) is deformed elastically by at least 0.01°, preferably at least 0.15°, by way of the contact of the corresponding face (19) on the stop face (17).
5. Injection valve according to one of the preceding claims, characterized in that the stop face (17) is divided into an inner section (23) and an outer section (24), the inner section (23) lying closer to the longitudinal axis (15) than the outer section (24), and the angle (α) without the contact of the stop face (17) and the corresponding face (19) being greater on the outer section (24) than on the inner section (23).
6. Injection valve according to Claim 5, characterized in that the inner section (23) without the contact of the stop face (17) and the corresponding face (19) is parallel to the corresponding face (19) or inclined with respect to the corresponding face (19) or concave.
7. Injection valve according to one of the preceding claims, characterized in that an outer face (21) of the stop element (21), which outer face (21) faces away from the corresponding face (19), is configured so as to be inclined with respect to the stop face (17) at least in places and/or is configured so as to be parallel to the stop face (17) at least in places and/or is configured so as to be concave at least in places.
8. Injection valve according to one of the preceding claims, characterized in that the stop element (12) comprises at least one groove (22) which is preferably circumferential.
9. Injection valve according to one of the preceding claims, characterized in that the first stop is formed by way of a ring (10) or a shoulder on the valve needle (6).

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