DE102007043538A1 - Injector with hydraulic damper - Google Patents

Abstract

The invention relates to an injector (1) for injecting fuel into the combustion chamber of an internal combustion engine, in particular a common rail injector, with an injection valve element (9) which is dependent on the pressure in a control chamber (11) between a closed position and an open position axial direction is adjustable, wherein the control chamber (11) by means of an adjustable control valve element (17) having control valve (18) is hydraulically connectable to an injector return port (6). According to the invention, the control valve (18) is assigned a hydraulic damper (36) with at least one defined throttle (40), through the fuel, by a displacement movement of the control valve element (17) in a first direction of movement (22), in a first Direction is promoted and is promoted by the fuel, in an adjusting movement of the control valve member (17) in a second, the first direction of movement opposite direction, in a second direction (43).

Description

State of the art

The The invention relates to an injector, in particular a common rail injector, according to the generic term of claim 1.

Of the Advantage of injectors designed as common rail injectors lies in the independence of the Injection pressure of the speed and the load of the internal combustion engine. For the Compliance with future Exhaust emission limits, it is necessary, especially in diesel engines, a significant increase to achieve the injection pressure. For this reason, so-called leak-free injectors have become known in which to a low-pressure stage was waived. Due to the lack of low pressure stage stand However, only comparatively small injection valve element closing forces for Available. this leads to steep maps and thus to a poor Kleinstmengenfähigkeit. This disadvantage can be with very fast switching control valves be compensated.

Fast switching However, control valves usually have the disadvantage that due to a Bouncing the control valve element on the control valve seat and on a stop facing away from this for the control valve element map ripples occur. The bouncing of the control valve element occurs in particular in a hard stroke stop in conjunction with a fast control valve element in appearance. To the hard impact of the control valve element to dampen at a stop, It is known to use so-called squeeze gaps, the impact dampen hydraulically. The damping effect is on the increasing with decreasing nip Reynolds number, So an increased Attributed friction of the fuel at the gap walls. However, squeeze gaps have the negative characteristic that when closing the control valve, so at the movement of the control valve element towards its control valve seat, a hydraulic force occurs that delays the closing. This effect is called designated hydraulic bonding and is particularly to the at minimized nip due to increased friction. The Hydraulic bonding is like external influences depending on the fuel pressure and the fuel temperature, thereby it comes to Hub / Hub scatters.

Preller as mentioned, not only when opening the control valve, but also when closing the control valve in appearance, when the control valve element at a high speed hits the control valve seat. These bouncers have a special effect negative for the injector function and usually lead to very large Hub / Hub scattering. Unlike when striking the control valve element to an axial stop can on the control valve seat due to its sealing function no nip be provided.

One Another disadvantage of known injectors is that a high Impact impulse not only to closing bouncers, but also to Significant wear in the Area of the control valve seat leads.

Disclosure of the invention

Technical task

Of the The invention is therefore based on the object of proposing an injector, at the Steuerventilelementpreller both when opening and closing the Control valve can be avoided and beyond no hydraulic Sticking in the opening or closed position the control valve element occurs.

Technical solution

These Task is with an injector with the features of the claim 1 solved. Advantageous developments of the invention are specified in the subclaims. All combinations of at least two also fall within the scope of the invention in the description, claims and / or drawings disclosed features.

The invention is based on the idea to provide a hydraulic damper for the control valve element, which is effective both in the opening direction and in the closing direction of the control valve element. This hydraulic damper is realized in that it has at least one hub-independent, that is to say defined, throttle, through which the fuel is caused by an adjusting movement of the control valve element. In this case, the conveying direction of the fuel through the defined throttle depends on the direction of movement of the control valve element. During an adjusting movement of the control valve element in a first direction of movement, for example in the opening direction, fuel is conveyed on the basis of this Ver adjusting movement of the control valve element or a component connected thereto in a first direction through the throttle. During an adjusting movement of the control valve element in the opposite second direction of movement, that is, for example, the closing direction, fuel is conveyed in a second direction, which is opposite to the first direction, through the defined throttle. In this case, the defined, hubunabhängige throttle, for example, be formed by at least one bore, or at least one guide or sealing gap. By occurring at the throttle Pressure difference and the promotion of fuel through the defined throttle is "destroyed" energy and it enters a damping or throttling effect, which throttles the displacement of the control valve element, regardless of the direction of movement of the control valve member proportional to the square of the adjustment of the control valve element Actuator force of an electromagnetic actuator or a piezo actuator when opening or the closing spring force when closing the control valve does not lead to a continuous acceleration of the control valve element, but rather a constant speed sets in. As a result, the impact speed both at the control valve seat when closing the control valve and at the axial stop When the control valve is opened, it can be greatly reduced, thus providing hydraulic damping by means of a state of the art Technology known Quetschspaltes superfluous, which also eliminates the associated with this negative property of hydraulic bonding.

From It is particularly advantageous if the with the control valve element Actively connected hydraulic, acting in both adjustment directions hydraulic dampers with a strong closing spring and / or an actuator with a high adjustment force is combined. in the Unlike known valves without hydraulic dampers leads a trained according to the concept of the invention injector the size Adjusting force does not lead to a significant increase in the impact momentum, but only that the maximum, constant speed of the Control valve element is achieved quickly, resulting in short switching times of the control valve can be realized. The impact pulse is due to the hydraulic throttling and the resulting constant maximum speed of the control valve element a minimum while reduced those by the stronger ones Pen and / or the stronger one Actuator achieved locking or stopping force a rebound the control valve element is prevented. Thus leads a Magnification of the closing spring or the use of an actuator with an increased power surprising Way to reduce the bounce. For injectors without a hydraulic damper described above would provide a corresponding Verstellkrafterhöhung an increase in the impact momentum and an increase in the Lead bounce.

From It is particularly advantageous, the hydraulic damper in the low pressure range to arrange. Here, the fuel can be considered incompressible, whereby pressure oscillations in the damper avoided become.

From particular advantage is an embodiment at the hydraulic damper a first damper room having the at least one defined, hubunabhängige throttle assigned. This first damper room is from the control valve element or one connected to this or one piece limited with this trained component. This leads to, that during an adjusting movement of the control valve element, the volume of the first damper room changed becomes. For example, is the volume at an adjustment of the control valve element is reduced in the first direction of movement, so increased the pressure within the first damper space and fuel becomes pressed out by the defined throttle from the damper space (promoted). As a result, the adjustment speed of the control valve element damped in the first direction of movement. On the other hand, it increases the volume of the damper space in an adjusting movement of the control valve element into a second, the direction of movement opposite to the first direction of movement, so that a negative pressure arises within the first damper space, whereby a suction effect results because of their fuel through the defined throttle into the damper chamber is sucked. This in turn dampens the adjustment speed of the control valve element in the second Movement.

Of particular advantage is an embodiment in which the hydraulic damper in addition to the first damper chamber has at least one further, second damper chamber, wherein the second damper chamber is preferably limited by the control valve member or a connected thereto or integrally formed with this component. The two damper chambers are hydraulically connected to each other via the at least one defined throttle. Here, it is conceivable to provide a direct hydraulic connection between the damper chambers by the defined throttle opens into the first damper chamber and opens into the second damper chamber. Alternatively, it is conceivable to connect the two damper chambers indirectly, for example via at least one intermediate space, in which case preferably a defined throttle leads from the intermediate space into the first damper space as well as into the second damper space. Preferably, the gap itself is not volume variable. The coupling of the two, preferably separated from the other low-pressure region, damper chambers causes when the control valve element is adjusted in the first direction of movement and thereby reduces the first damper space, the second damper space is increased simultaneously. The fuel is thus pushed out by the positive pressure in the first damper chamber from the first damper chamber through the defined throttle and the volume increase of the second damper chamber in the sucked sen. In the opposite case, that is to say with an adjustment movement of the control valve element in the second direction of movement, the first damper space is increased and the second damper space is reduced, which in turn increases It is within the scope of the invention to separate both damper chambers from the low pressure region of the injector, or else the second damper chamber in the latter case, the volume change of the second damper space is negligible in relation to its size form, in which the two damper spaces are at least approximately the same size.

From particular advantage is an embodiment in which the control valve element sleeve-shaped and preferably in the closed Condition is formed pressure balanced in the axial direction. This can preferably be realized by a sealing edge (seat edge) on the inner circumference of the sleeve-shaped control valve element is arranged so that a pressure stage on the control valve element, which cause a force in the axial direction on the sleeve-shaped control valve element would, is avoided.

From particular advantage is an embodiment the injector, wherein the sleeve-shaped control valve element encloses a pressure pin, as separate from the component having the control valve seat Component is formed. This embodiment has a variety of advantages. So in particular the control valve seat is at his Production easily accessible. About that in addition, if necessary, the leadership for the sleeve-shaped control valve element and the control valve seat is executed on different components and to be processed separately from each other. The pressure pin has doing the task, a valve disposed within the valve sleeve valve chamber Seal in the axial direction. Optionally, the pressure pin and in particular in a positionally fixed arrangement as an inner guide for the control valve element serve. The push pin supports itself, in particular spring-assisted, at one of the control valve element seat in the axial direction spaced construction part from, or is optionally one piece formed with such a component. Alternatively, it is think bar, the pressure pin in one piece form with the control valve seat having the component.

to Training and arrangement of the hydraulic damper, there are different Options.

According to one First preferred alternative is the first damper space radially outside arranged the control valve element. The first damper space is preferred doing of a diameter stage of the control valve element and a the control valve member enclosing component, in particular a guide plate to the outer leadership of the Valve element, limited. The second damper space is preferably within arranged the control valve element. The two damper chambers can have one designed as a radial bore, defined Throttle be interconnected. The second damper space is preferred bounded by an inner annular shoulder of the control valve element. Advantageously, the second damper chamber on the side of the inner ring shoulder opposite one on a pressure pin received within the control valve element seat limited trained ring shoulder.

According to one second alternative, the hydraulic damper is designed such that the first and the second damper space axially spaced apart within a cap member are, wherein the cap member preferably radially outward of is enclosed under low pressure fuel and preferred by means of a spring against a component of the injector, preferably against a guide plate to the leadership the control valve element on its outer circumference, spring force is. In the axial direction, the two damper chambers are separated by a ring element separated, either in one piece formed with the control valve element or fixed to this is. It is conceivable, the two damper chambers directly with a defined To connect throttle, for example, from a circumferential gap can be formed between the ring element and the cap element, or at least one bore within the ring element. However, an embodiment is preferred in the two damper chambers, preferably over each at least one defined throttle, with a volume constant Intermediate space within the control valve element hydraulically connected are, with this gap in both axial directions of one radially thickened portion of one within the control valve element arranged pressure pin are limited. It is also an embodiment with a gap and only a single defined throttle realizable.

According to a third alternative, which is realized only in an electromagnetically actuated control valve element, the two damper chambers in the axial direction of an armature plate is limited, which is either formed integrally with the control valve element or fixed thereto. The defined throttle can be formed by a circumferential gap between the armature plate and a surrounding component, preferably a support ring for an electromagnet assembly. Additionally or alternatively, it is conceivable to provide a defined throttle bore in the axial direction in the armature plate. It is preferred in such an embodiment that the fuel is not performed directly by the hydraulic damper forming the armature space to injector return, but in this case within the hülsenför shaped control valve element is provided in the axial direction leading annular channel, which preferably directly into a radial inside a solenoid assembly disposed spring chamber and from there to the injector return port leads.

From particular advantage is an embodiment in the case of a reliable filling of the at least one damper space is ensured. This can be realized by the fact that at least one damper room over at least a sealing or guiding gap, at least temporarily, with a high pressure area of the injector and over one another sealing or guiding gap, preferably permanently, to the low pressure area of the injector is connected, wherein the flow area of the high pressure area facing sealing or guide gap to be taller should be considered that of the permanently connected to the low pressure area Sealing or guide gap. When the control valve is closed, therefore, the damper space is preferred with a leakage amount and not with a gas-containing tax amount filled. This embodiment has the consequence that within the at least one damper chamber one opposite the Low pressure range increased Pressure level prevails. about the hydraulic connection of the at least one damper chamber on the mentioned leakage column ensures that in the at least one damper room There are no air bubbles through which the damping effect of the hydraulic damper would be reduced.

Especially to the effects of an increased To avoid pressure levels within the damper chambers is an embodiment advantageous in which the effective in the axial direction pressure application surfaces in equal to the damping chambers are big, such that there is no resultant compressive force from the damper spaces to the control valve member acts.

From particular advantage is an embodiment when a big, d. H. strong, closing spring for the Control valve is provided. Preferably, the spring force of the closing spring is more as 30 N, preferably more than 40 N, more preferably more than 50 N.

Brief description of the drawings

Further Advantages, features and details of the invention will become apparent the following description of preferred embodiments and by reference the drawings. These show in:

1 A first embodiment of an injector with a hydraulic damper, wherein a first damper space is arranged radially outside of a sleeve-shaped control valve element and a second damper space within the control valve element.

2 an alternative embodiment of an injector in which two damper chambers are enclosed by a cap member and are separated in the axial direction via a ring element of the control valve element, and

3 : Another embodiment of an injector, wherein the hydraulic damper is formed within an armature space.

Embodiments of the invention

In The figures are the same components and components with the same Function marked. In the embodiments shown are only Injectors with electromagnetic actuator shown. Besides The use of piezoelectric actuators is also possible.

In the figures, a fragment designed as a common rail injector injector 1 for injecting fuel into a combustion chamber of an internal combustion engine of a motor vehicle. A high pressure pump 2 Promotes fuel from a reservoir 3 in a high-pressure fuel storage 4 (Rail). In this fuel, especially diesel or gasoline, is stored under high pressure of about 2000 bar in this embodiment. To the high-pressure fuel storage 4 is the injector 1 besides other, not shown, injectors via a supply line 5 connected. Via an injector return connection 6 is the injector 1 to a return line 7 connected. Through this, a later to be explained control amount of fuel from the injector 1 to the reservoir 3 drain and be fed from there from the high pressure circuit again.

The injector 1 includes an integral in this embodiment injection valve element 9 , which can also be made in several parts if necessary. The injection valve element 9 is adjustable in the axial direction. It has at its tip, not shown, a closing surface with which the Einspritzven tilelement 9 in a tight contact with an injection valve member seat, not shown, can be brought. When the injection valve element 9 abuts against its injection valve element seat, that is, is in a closed position, the fuel outlet is blocked from a nozzle hole arrangement, also not shown. If, on the other hand, it is lifted from its injection valve element seat, fuel can flow past the injection valve element seat to the nozzle hole arrangement and be sprayed there into the combustion chamber, standing substantially under the high pressure (rail pressure).

From an upper front side 10 the injection valve element 9 becomes a control chamber 11 limited, via a running in the radial direction inlet throttle 12 permanently supplied with high-pressure fuel. The control chamber 11 is about one, in a valve body 13 arranged drainage channel 14 with outlet throttle 15 with a valve chamber 16 connected by an axially adjustable, sleeve-shaped control valve element 17 a pressure balanced in the axial direction in the closed state control valve 18 (Servo valve) is limited. From the valve chamber 16 can fuel in a low pressure area 19 of the injector 1 and from there to the injector return port 6 flow when the control valve element 17 , which with an anchor plate 20 is integrally formed by his on the valve body 13 trained control valve seat 21 is lifted, that is the control valve 18 is open.

For adjusting the control valve element 17 in the plane of the drawing up, in a first direction of movement 22 , is an electromagnet arrangement 23 provided, which is an electromagnet 24 (Coil), which in a holding body 25 is held. The electromagnet 24 acts with the anchor plate 20 Together, in an anchor room 26 is arranged. Due to the one-piece design of the control valve element 17 with the anchor plate 20 raises the control valve element 17 during energization of the solenoid assembly 23 from his control valve seat 21 from. The flow cross sections of the start-up throttle 12 and the outlet throttle 15 are matched to one another in such a way that when the control valve is open 18 a net outflow of fuel (tax amount) from the control chamber 11 over the valve chamber 16 in the low pressure area 19 of the injector 1 and from there to the injector return port 6 through the return line 7 in the reservoir 3 flows. This reduces the pressure in the control chamber 11 rapidly, causing the injection valve element 9 lifts from its injection valve element seat, so that in the sequence fuel is injected into the combustion chamber.

To end the injection process is the energization of the solenoid assembly 23 interrupted, causing the control valve element 17 by means of a at the anchor plate 20 supporting closing spring 27 that inside a spring chamber 28 is included within the holding body 25 is arranged, in the drawing plane down to its control valve seat 21 is adjusted. The through the inlet throttle 12 in the control chamber 11 inflowing fuel ensures a rapid rise in pressure in the control chamber 11 and thus for one on the injection valve element 9 newly acting closing force. This closing force is by a closing spring, not shown, located on a peripheral collar of the control valve element 17 supports, supports.

In the sleeve-shaped control valve element 17 protrudes a pressure pin 29 into it, the valve chamber 16 limited in the drawing plane to the top axially. The pressure pin 29 extends in the axial direction in the spring chamber 28 into and supported on a cover element 30 of the injector 1 from. To the pressure pin 29 in turn, or at its contact section, the closing spring is supported 27 from.

With open control valve 18 the fuel first flows into an annulus 31 and from there via axial channels 32 in the anchor room 26 , From there, the fuel flows through radial bores 33 in a central channel 34 within the control valve element 17 inside at the anchor plate 20 passing directly into the spring chamber 28 into and out of the injector return port 7 ,

To both Preller of the control valve element 17 during its closing movement on the control valve seat 21 as well as Preller at an axial stop 35 at an opening movement of the control valve element 17 To avoid is a hydraulic damper 36 intended. The hydraulic damper 36 includes a first damper space 37 that is radially outside of the control valve element 17 arranged and designed as an annular space. In the axial direction in the drawing plane down the first damper space 37 from an annular pressure application surface 38 Limited (diameter stage) of the control valve element. Otherwise, the first damper room 37 in the radial direction and in the axial direction of an outer guide element 39 for the control valve element 17 limited. About a defined, as a radial bore in the control valve element 17 engineered throttle 40 is the first damper room 37 hydraulically with a second damper space 41 connected, which also as an annulus, but within the control valve element 17 is trained. In the axial direction in the drawing plane up the second damper space 41 limited by an annular pressure application surface 42 the control valve element 17 , In the axial direction in the drawing plane down the second damper space 41 bounded by a thickened section of pressure pin 29 (Annular shoulder). In the radial direction, the second damper space is bounded by an inner circumferential wall of the control valve element 17 , Will the control valve element 17 by energizing the solenoid assembly in the first direction of movement 22 adjusted, the volume of the first damper space decreases 37 and the volume of the second damper space 41 increases. The resulting pressure difference between the damper chambers 37 . 41 causes fuel through the throttle 40 from the first damper room 37 in the second damper room 41 is promoted, which in turn the opening speed of the control valve element 17 is throttled or damped proportional to the square of the opening speed. In contrast, the control valve element 17 in a second, the first direction of movement 22 opposite direction of movement 43 adjusted, fuel from the second damper chamber 41 through the throttle 40 in the first damper room 37 promoted, whereby the closing speed of the control valve element 17 is attenuated in proportion to the square of the closing speed. In particular, by the combination with a strong closing spring 27 with a spring force of in this embodiment 45 bar buffers of the control valve element 17 at the control valve element seat 21 as well as Preller of the control valve element 17 at the axial stop 35 avoided.

The filling of the second damper space 41 (and about the throttle 40 of the first damper room 37 ) with fuel is using the high-pressure leakage over a first sealing guide gap 44 radially between the control valve element 17 and a lower thickened portion of the pressure pin 29 realized. Characterized in that the flow through the first sealing guide gap 44 greater than the flow through a second sealing guide gap 45 radially between a thin section of the pressure pin 29 and the control valve element 17 in an area in the plane of the drawing above the second damper space 41 , turns into the damper rooms 37 . 41 a higher pressure level than in the low pressure range 19 , which is hydraulic with the injector return port 6 connected is. In this way, a reliable filling of the damper chambers 37 . 41 ensured. It is advantageous that the pressure application area 38 the control valve element 17 in the first damper room 37 has the same area as the pressure acting in the opposite direction pressure application surface 42 on the control valve element 17 in the second damper room 41 , which due to the higher pressure level in the damper chambers 37 . 41 no resulting hydraulic force on the control valve element 17 acts.

In the following, the embodiments according to the 2 and 3 explained. To avoid repetition, essentially only the differences from the embodiment according to FIG 1 received. With regard to the similarities is on the previous figure description as well as on 1 directed.

At the in 2 illustrated injector 1 is one compared to 1 differently designed hydraulic shear damper 36 intended. The hydraulic damper 36 includes a cap member 46 that by means of a coil spring 47 in the axial direction in the plane of the drawing, upwards to an outer guide element 39 of the injector 1 is pressed. On the control valve element 17 is a ring member extending in the radial direction 48 set that of the cap member 46 enclosed space in an axially upper first damper space 37 and a second damper space disposed in the axial direction below 41 divided. The two damper rooms 37 . 41 are each a defined, as a radial bore in the sleeve-shaped control valve element 17 trained throttle 40 with a volume-constant gap 49 connected within the control valve element 17 is arranged. In the radial direction is the gap 49 limited by the control valve element 17 , In the opposite axial direction is the gap 49 bounded by two thickened portions of a guide pin 29 , Over a first sealing guide gap 44 radially between the control valve element 17 and a lower, thickened portion of the pressure pin 29 becomes the gap 49 and thus the two damper rooms 37 . 41 filled with leakage fuel. The pressure in the damper chambers 37 . 41 and the gap 49 can be with the second sealing guide gap 45 Set by an appropriate choice of the gap and the length.

The game of a seal leadership 50 between the ring element 48 and the cap member 46 as well as a game of another seal guide 51 radially between the cap member 46 and the control valve element 17 need only be sized so small that the leak occurring there has little or no effect on the damper function. The sealing gap 52 radially tilelement between the Steuerven 17 and the outer guide element 39 not only has a sealing function, but also positions the control valve element 17 , For this reason, the gap width of the sealing gap 52 chosen smaller than would be necessary for a purely hydraulic seal.

Will the control valve element 17 by energizing the electromagnet 24 from the control valve element seat 21 lifted, ie in the first direction of movement 22 Moves, fuel is from the first upper damper space 37 over the top of the drawing plane throttle 40 in the gap 49 pressed and from there, in particular by in the second damper room 41 due to its increase in volume resulting suction in the second damper space 41 sucked. This results in a throttle effect of the opening speed, which is proportional to the square of this opening speed. During an adjustment movement in the second direction of movement 43 by interrupting the energization of the electromagnet 24 and due to the spring force of the strong closing spring 27 , the second damper space decreases 41 and the first damper room 37 is enlarged so that fuel from the second damper space 41 through the bottom of the drawing plane throttle and the gap 49 and by the upper in the drawing plane throttle 40 in the first damper room 37 is promoted, which in turn results in a damping of the closing speed of the control valve element 17 results. It is conceivable, just a throttle 40 to provide and a damper room 37 or 41 via a "throttle-free" bore to the gap 49 to tie.

In the embodiment according to 3 is the hydraulic damper 36 in an anchor room 26 formed, the hy cally at least largely the annulus 31 is decoupled, the control valve element 17 surrounds in an axially lower area. From the annulus 31 fuel flows when the control valve element is open 17 through radial bores 53 in a central channel 34 within the control valve element 17 and from there directly into the spring chamber 28 with closing spring 27 and from there over a bag 54 and a sloped channel 55 to the injector return port 6 ,

The anchor plate 20 separates a first damper space in the drawing plane 37 from a lower second damper space in the drawing plane 41 , These are over a defined, designed as an annular gap throttle 40 connected with each other. The throttle 40 is as a circumferential gap radially between the anchor plate 20 and a support ring 56 for the electromagnet arrangement 23 arranged. Optionally, a throttle bore 57 in the anchor plate 20 be provided, which serves to support and Entdrosselung the coil window. In an adjusting movement of the control valve element 17 in a first direction of movement 22 gets fuel from the first damper room 37 over the defined in this case as an annular gap defined throttle 40 in the second damper room 41 promoted. During an adjustment movement in the second direction of movement 43 Fuel is supplied in the reverse direction through the throttle 40 ,

Due to the throttling effect of the sealing gap 52 and the axially spaced therefrom sealing gap 58 in the area of the spring chamber 28 prevents a pressure increase in the damper chambers caused by a control shock 37 . 41 can migrate into it. The game of sealing gaps 52 . 58 However, it must be so large that a filling or venting of the damper chambers 37 . 41 is guaranteed. Nevertheless, a (small) positional tolerance of the control valve element 17 To realize the control can control in the region of the sealing gap 52 also as a polygonal guide with axial channels between the annulus 31 and the anchor room 26 be formed.

Claims (11)

Injector for injecting fuel into the combustion chamber of an internal combustion engine, in particular a common rail injector, having an injection valve element ( 9 ), which depends on the pressure in a control chamber ( 11 ) is adjustable between a closed position and an open position in the axial direction, wherein the control chamber ( 11 ) by means of one, an adjustable control valve element ( 17 ) having control valve ( 18 ) hydraulically with an injector return port ( 6 ), characterized in that the control valve ( 18 ) a hydraulic damper ( 36 ) with at least one defined throttle ( 40 ) is assigned, by the fuel, by an adjusting movement of the control valve element ( 17 ) in a first direction of movement ( 22 ), is conveyed in a first direction and by the fuel, during an adjusting movement of the control valve element ( 17 ) in a second, the first direction of movement opposite direction, in a second direction ( 43 ). Injector according to claim 1, characterized in that the throttle ( 40 ) a first damper space ( 37 ) associated with the control valve element ( 17 ) and / or a component connected thereto or integrally formed therewith, and in that the volume of the first damper space ( 37 ) at egg ner adjusting movement of the control valve element ( 17 ) in the first direction of movement ( 22 ) and thereby fuel through the throttle ( 40 ) from the first damper space ( 37 ) and that the volume of the first damper space ( 37 ) during an adjusting movement of the control valve element ( 17 ) in the second direction of movement ( 43 ) and thereby fuel through the first throttle ( 40 ) into the first damper space ( 37 ) is sucked. Injector according to one of claims 1 or 2, characterized in that the first damper space ( 37 ) one of the control valve element ( 17 ) and / or a second damper space bounded therewith or integrally formed therewith ( 41 ), the damper spaces ( 37 . 41 ) directly or indirectly via at least the throttle ( 40 ) are hydraulically connected to each other, and that the volume of the second damper space ( 41 ) at a Verbewegt tion of the control valve element ( 17 ) in the first direction of movement ( 22 ) increases by the amount by which the volume of the first damper space ( 37 ) and that the volume of the second damper space ( 41 ) during an adjusting movement of the control valve element ( 17 ) in the second direction of movement ( 43 ) decreases by the amount by which the volume of the first damper space ( 37 ) increases. Injector according to one of the preceding claims, characterized in that the control valve element ( 17 ) sleeve-shaped and, preferably in the closed state in the axial direction pressure balanced, is formed. Injector according to claim 4, characterized in that inside the sleeve-shaped control valve element ( 17 ) one of which the control valve seat ( 21 ) having valve body ( 13 ) separate pressure pin ( 29 ) is arranged. Injector according to one of the preceding claims, characterized in that the first damper space ( 37 ) as radially outside the control valve element ( 17 ) arranged annular space ( 31 ) is formed and the second damper space ( 41 ) within the control valve element ( 17 ), and that the throttle ( 40 ) as a bore in the control valve element ( 17 ) is trained. Injector according to one of claims 1 to 5, characterized in that the first and the second damper space ( 37 . 41 ) within one of the control valve element ( 17 ) penetrated cap element ( 46 ) are arranged, and that the damper spaces ( 37 . 41 ) via a ring member attached to the control valve element ( 17 ) or integrally formed therewith, are separated from each other in the axial direction. Injector according to one of claims 1 to 5, characterized in that the damper chambers ( 37 . 41 ) in the axial direction of one with the control valve element ( 17 ) Actively connected anchor plate ( 29 ) are separated, and that the throttle from a hole in the anchor plate ( 20 ) and / or from a circumferential sealing gap between the anchor plate ( 20 ) and a radially outer component of the injector ( 1 ) is formed. Injector according to one of the preceding claims, characterized in that the damper chambers ( 37 . 41 ) via a first, the control valve seat ( 21 ) facing sealing guide gap ( 44 ), which when the control valve is closed ( 18 ) is acted upon by high pressure and via a second, the Injektorrücklaufkanal ( 6 ) facing sealing guide gap ( 45 ) hydraulically to the high-pressure region or the low-pressure region ( 19 ) of the injector ( 1 ), wherein the flow cross section of the first sealing guide gap ( 44 ) is greater than that of the second sealing gap ( 45 ), so that in the damper rooms ( 37 . 41 ) sets a higher pressure level than in the low pressure range ( 19 ) of the injector ( 1 ). Injector according to one of the preceding claims, characterized in that the pressure application surface ( 42 ) of the control valve element ( 17 ) and / or of the component connected thereto or formed integrally therewith, with which the first damper space ( 37 ) is limited in a first axial direction and the pressure application surface ( 38 ) of the control valve element ( 17 ) and / or of the component connected thereto or integrally formed therewith, with which the second damper space ( 41 ) is limited in a second, the first axial direction opposite axial direction, are equal. Injector according to one of the preceding claims, characterized in that a closing spring ( 27 ) of the control valve ( 18 ) has a spring force of more than 30 N, preferably more than 40 N, particularly preferably more than 50 N.