DE102004042189A1 - Valve - Google Patents

Abstract

The invention relates to a valve, in particular a servo valve for a fuel injector in motor vehicle construction. The valve according to the invention comprises an axially movable valve member (10) and a valve body (15) having a passage bore (25) and a sealing seat (20) on which a sealing portion (35) of a free end portion of the valve member (10) in a closed position the valve seated sealingly. The free end portion of the valve member (10) has, in the closed position of the valve, a profiled portion (30) extending into or through the passage bore (25) and positionable within the passage bore (25) such that the profiled one Section (30) depending on its profile and a stroke of the valve member (10) in the passage bore (25) opens a variable flow area.

Description

The The invention relates to a valve, in particular a servo valve for a Fuel injector in motor vehicle construction.

In Automotive technology are fuel injectors with digital switching servo valves known only two positions one Valve member allow a fully open or fully closed. This restricts the possibilities of Fuel injection, in particular with respect to duration (v. a. with short injection times) and injection quantity into a combustion chamber strong. Due to the almost digital opening of the valve needle comes it in control rooms the injector to sudden pressure drops, resulting in a dosage of Small amounts almost impossible makes that particular for Pre and post injections is necessary.

This leads to an increased Consumption of the engine and above in addition, due to not optimal combustion, in addition to increased Exhaust emissions of the vehicle and to increased noise emissions, as a comparatively slow opening and a quick closing the nozzle needle or a pre-injection are not possible. Furthermore, such Concepts high switching leakage currents on (only a fraction of the per crankshaft revolution funded Fuel is actually injected into the engine), which the high-pressure pump (power consumption at full load approx. 3 to 10 kW) must compress and feed again.

this sudden pressure drops can be countered by inlet and outlet throttles on the servo valve. But since the throttles have constant cross sections, the flexibility is, especially at Concepts with two nozzle needles, the slow opening the first nozzle needle and a sudden opening the second nozzle needle require, severely restricted. Only for a point in the map can optimal conditions are achieved.

Furthermore, from the EP 0 741 244 A2 an injection nozzle of a common rail system is known, which adjusts a valve member of a servo valve with known sealing geometry in two steps according to an electrical signal by means of a piezoelectric actuator, wherein the servo valve has a square, approximately linear or logarithmic flow characteristic.

Of the Invention is therefore based on the object, a valve, for. B. for one Fuel injector of a common-rail injection system, available too put that to reduce fuel consumption, exhaust emissions and the noise emissions one possible flexible injection, especially in terms of injection quantity, duration and type (clocked / not clocked, with / without pre / post injection, Design of the nozzle needle stroke dependent on from the time), with as possible low switching leakage allows.

These Task is solved with a valve according to claim 1. preferred Trainings are in the dependent claims According to the invention is a special profile design of a free end portion of a movable valve member (valve member) of a valve provided.

Prefers protrudes or protrudes through this valve member in a closed position the valve has a passage bore, wherein a free end portion the valve member disposed within the passage bore such can be that a profile section of the free end section in dependence from the stroke of the valve member and the geometry of the profile section opens a variable flow area.

With Help of the geometry of the profile section becomes the discharge cross section the valve by interaction of this geometry with the valve member stroke within defines the passage bore. This profile section can the Flow of fluid through the valve over long distances of the valve member stroke or over the throttle the entire stroke of the valve member.

hereby is z. B. the outlet throttle in a fuel injector superfluous and takes over the valve additionally the function of a variable throttle, which in turn allows not just one but a variety of points of the map optimal implement. By means of the profile section according to the invention breaks a pressure in a control room no longer abruptly together, but builds up according to the throttling profile section only delayed and to an arbitrary Pressure level, which by tuning of inflow and outflow volume is adjustable. By means of this control pressure or flow cross-section modulation can be the opening characteristic the nozzle needle (s) and thus adjust the injection rate arbitrarily to the needs of the engine.

According to the invention, the Flow characteristic of the valve over the entire stroke of the valve member can be made freely selectable to so for preferably many points in the map to achieve optimal conditions.

The Valve member is directly or indirectly, in particular by means of a piezoelectric actuator, preferably half-stroke reciprocating.

One Piezo crystal leaves also against high pressures drive with partial means or with continuous flow, what for. B. makes the construction of a pressure balanced valve superfluous. Pressure compensated valves cause additional leakage that affects performance reduce the gear, so the one for the movement of the vehicle to disposal stands.

Of the Flow through the valve is by means of shaping of the profile section and / or the passage bore almost arbitrarily adjustable.

This allows it for many points in the map optimal conditions without great constructive To achieve effort. Under forms have the same throttle effect, the one with the least wear can be selected.

In a preferred embodiment arises between the profiled section in the passage bore and the inner wall of the passage bore has a substantially hollow cylindrical gap volume.

This is especially at voltage fluctuations of the actuator drive unit advantageous as it is thus possible is for certain supply voltage ranges always the same flow cross-section to open. Ie. an exact voltage supply can be dispensed with.

at a preferred embodiment The profiled section comprises a composite of two pointed truncated cones Extension of the free valve member end, preferably in one piece on the free End of the valve member is formed. A truncated cone can do this a cylindrical portion provided for the smallest annular gap is.

These Shape is great for a pre and subsequent main injection. For the pre-injection are gap widths (due to the cylinder portion) provided in one to two-digit micron range. The one-piece Training on the valve member gives the valve a longer life.

For a "fine" setting the Flow characteristic, it is advantageous on the profile section a Flächenanschliff provided. If this is at an angle with respect to the valve member axis executed is the slope of the flow characteristic, in particular the linear Sections, adjustable in wide ranges.

In a preferred embodiment is it for an exact dosage of the injection or flow rate and thus also for the movement curve of the nozzle needle in the time of great Advantage if the deforming components when opening the Valve are taken into account when Ventilgliedteilhub.

The Invention will be described below in embodiments with reference to FIG associated Drawing closer explained. Show it:

1 FIG. 2 is a general schematic of a prior art fuel injector. FIG.

2 : an injector according to the invention with a servo valve according to the invention,

3 a sealing section of the servo valve according to the invention in the closed position in side view,

4 : a front view of the 3 .

5 : Flow characteristics of the servo valve according to the invention in comparison with flow characteristics of a servo valve according to the prior art.

1 shows the basic structure of a servohydraulisch actuated, stroke-controlled injector 100 a common rail injection system for diesel vehicles according to the prior art with a digitally switching, electromagnetically actuated 2/2-servo valve 105 (2 connections / 2 switching positions), one inlet throttle 110 , an outlet throttle 115 as well as a control room 120 , an injector or nozzle needle 125 and a nozzle space 130 , Digital switching in this context means that the 2/2-Servovalve 105 only has two fixed valve member positions: fully open and fully closed. The servo valve switches between these two positions 5 abruptly back and forth.

The injector 100 According to the prior art operates as follows: The control room 120 is via a supply line 140 and the inlet throttle 110 with high pressure fuel from a rail 135 supplied, which ensures an influx of fuel with constant high pressure. Further, the control room 120 over the outlet throttle 115 and the 2/2 servo valve 105 with a return line 145 connected, which opens into a standing under ambient pressure fuel tank. In the illustrated state is the 2/2-Servovalve 105 closed and in the supply line 140 , the inlet throttle 110 , the control room 120 , the outlet throttle 115 and the nozzle space 130 There is a common pressure, the so-called rail pressure (up to more than 2,000 bar). In this position is the injector 100 closed; it does not find any injection of fuel into the engine space instead. At the beginning of an injection, the servo valve 105 open, fuel flows from the control room 120 through the outlet throttle 115 and the servo valve 105 to the return line 145 , At the same time, fuel flows via the supply line 140 and the inlet throttle 110 to the control room 120 , By a different dimensioning of the effective throttle cross-section between inlet throttle 110 (comparatively small) and the outlet throttle 115 (comparatively large) arises in the control room 120 abruptly a lower pressure than in the rail 135 and therefore also in the nozzle space 130 at the nozzle needle base. The nozzle needle 125 is pushed upwards by the high-pressure fuel at a pressure shoulder or the like provided for it; the injection begins. To complete the injection, the 2/2-Servovalve 105 closed again and the control room 120 via the inlet throttle 110 filled. This is the nozzle needle 125 from the fuel pressure in the control room 120 and possibly a nozzle spring 150 pressed down; the injection is finished.

2 shows an injection nozzle according to the invention with a servo valve according to the invention 5 , It should be noted at this point that the invention is not limited to servo valves for injectors o. Ä., But should include valves that are generally used as valves with variable throttle function or variable flow area. Same components of the 2 With 1 are in 2 provided with the same reference numerals.

In contrast to 1 shows 2 an injection nozzle without outlet throttle and with preferably piezoelectrically operated servo valve 5 , In this case, the servo valve 5 For example, a 2/4-Servovalve (2 connections / 4 switch positions), which may vary depending on the application of the valve. Thus, for example, 2/2, 2/3, 2/5-servo valves or those with even more switching positions are just as conceivable as valves with partially or fully continuously movable valve member, depending on the particular application and the requirements for the servo valve 5 depends. A variation of the valve member speed, including stops of the valve member at a certain stroke, is also conceivable. Furthermore, it is possible the servo valve 5 not to operate on a piezoelectric actuator, but z. B. via an electromagnetic actuator, in particular in pressure-balanced valves 5 Can bring benefits.

The servo valve 5 is preferably controlled stepwise and preferably by means of a piezoelectric actuator. This opens up further degrees of freedom in the design of servo valves 5 , in particular of these displaceable valve members and / or their passage bores, whereby the servo valve 5 can take over the function of the outlet throttle, which then makes them obsolete again. The servo valve 5 is extended to the function of a variable throttle. This is exemplified by a particular embodiment of an example 3 and in 4 shown valve member 10 allows.

The 3 and the 4 each shows a section of a valve 5 in closed position (ie valve 5 completely closed and fluid tight). In an open position of the valve 5 There will be a pressure drop at this section.

The servo valve 5 has a directly or indirectly with an actuator (not shown) operable valve member 10 and a valve body 15 with, preferably cylindrical, passage bore 25 or transmission aperture. The valve body 15 has a sealing seat 20 on, at which a sealing portion 35 of the valve member 10 in the closed position of the servo valve 5 sitting tightly. In this embodiment, immediately adjacent to the sealing seat closes 20 of the valve body 15 the passage bore 25 at. However, this is not absolutely necessary, as well can passage hole 25 and seal seat 20 be further away from each other. Below, in the 4 shown, connects to the servo valve 5 the control room 120 of the injector or the line to the control room 120 on, while the upper space of the servo valve 5 to the return line 145 and from there leads to the ambient pressure fuel tank.

The valve member 10 has at its free end portion a profiled section 30 on, at least in the closed position of the valve 5 into the passage hole 25 into or through it. With free end portion of that part of the valve member 10 denotes the on the side facing away from the actuator side of the valve member 10 lies. This end portion may be more than 2/3 of the entire length of the valve member 10 be, which may be the case in particular with pressure balanced valves and / or valves with three connections.

• • bei einem druckausgeglichenen (Vorteil: ermöglichen aufgrund geringer Ventilbetätigungskräfte nur eine kleine Ausführung des Aktuators), außenöffnenden Servoventil zwischen dem fluiddichtenden Abschnitt des Ventils und dem zusätzlich geführten Kolben;
• • bei einem druckausgeglichenen, innenöffnenden Servoventil zwischen dem fluiddichtenden Abschnitt des Ventils und dem Richtung Aktuator weiterführendem Abschnitt des Ventilglieds (also gegenüber des zusätzlich geführten Kolbens) angeordnet ist; und
• • bei Servoventilen mit drei Anschlüssen können zwei (unterschiedlich) profilierte Abschnitte am Ventilglied vorgesehen sein, die wiederum je nach Bauart (druckausgeglichen/nicht druckausgeglichen, außenöffnend/innenöffnend, sowie Kombinationen davon) an unterschiedlichen Stellen des freien Endabschnitts des Ventilglieds angeordnet sein.

It should be noted that the profiled section 30 not necessarily, as in the 3 and 4 shown must be an extension that extends at the end of the valve member 10 located. It is also conceivable that this profiled section 30 z. B .:

• In the case of a pressure-balanced (advantage: due to low valve actuation forces, only a small version of the actuator), an externally opening servovalve between the fluid-tight section of the valve and the additionally guided piston;
• In the case of a pressure-balanced, inwardly opening servovalve, between the fluid-sealing section of the valve and the section of the valve member which extends further away from the direction of the actuator (that is, with respect to the additionally guided piston) ordered is; and
• • For three-port servovalves, two (differently) profiled sections may be provided on the valve member, which in turn may be located at different locations on the free end portion of the valve member, depending on the design (pressure balanced / non-pressure balanced, external / internal opening, and combinations thereof).

The section 30 now extends the function of the servo valve 5 on the one of a servo valve 5 with variable throttle cross section. Therefore you can see the section 30 Also referred to as throttle section and here in this embodiment as throttle extension or throttle pin. In addition, the function of the passage bore ( 25 ) on the one throttle bore.

The servo valve 5 works as follows: At the beginning of an injection, for z. B. a pre-injection (similar can be moved with a post-injection), the valve member 10 with a first partial stroke, only a small piece from the passage bore 25 moved out, so due to a geometry of the profiled section 30 a very small annular gap (preferably in the one to two-digit micron range) is formed. The pressure in the control room 120 does not build up abruptly anymore but escapes in a controlled manner, which means precise control of the nozzle needle 125 allows and therefore an accurate adjustment of the injection quantity and the opening speed of the nozzle needle 125 , Thus, any pressure level in the control room 120 selectable, which results from the coordination of inflow and outflow volume. After completing this pilot injection, it is z. B. possible the servo valve 5 close again and then with a second, larger partial lift the main injection, which may be timed to start or the valve member 10 Immediately further out of the passage bore 25 with a second partial stroke either completely or not quite up to the stop of the valve member 10 to move and thus initiate the main injection.

The opening and / or closing speed of the nozzle needle 125 and the injection quantity (pre and post injection, main injection or non-pulsed injection, nozzle needle guidance during the main injection) can be adjusted by adjusting the valve member strokes (partial strokes with continuous or discontinuous valve member movements or a slow full stroke) and the corresponding profile of the segment 30 set as desired.

So can the profiled section z. B: In places (rotationally) symmetrical or be asymmetrical; the treads can have hard edges (lower Edge radius or discontinuities (sharp edge)) or soft Edges (larger edge radius) exhibit; Sectionwise, the profile section can be cylindrical, conical, frustoconical, ellipsoid, spherical, barrel-shaped or designed with rotationally symmetric surfaces of higher order is; it can there are polishes on it; a widening again (increasing the Diameter) of the section with increasing Ventilgliedhub is possible. any Combinations of these embodiments are of course possible as well also any volumes with idealized discontinuous surface transitions.

A preferred embodiment of the servo valve according to the invention 5 with the inventive free profiled end portion of the valve member 10 is partially in the 3 and 4 shown.

The valve member 10 has as profile section 30 a stepped extension in the closed position of the servo valve 5 through the passage hole 25 through, but also can only protrude into this. The extension is mainly composed of two substantially pointed truncated cones 65 . 70 put together over a short transition 75 having a flat truncated cone shape, connected to each other steadily, ie with rounded abutting edges. This extension of the valve member is preferred 10 formed integrally with this.

The truncated cone 65 with the largest existing diameter closes with the side of its largest diameter directly to the sealing section 35 of the valve member 10 at. At the side of this truncated cone 65 , which has the smallest diameter closes the transition 75 to which in turn the truncated cone 70 with the smallest diameter, but with the side of its largest diameter. The smallest diameter of this truncated cone 70 is rounded at its free edges and preferably protrudes into the control room 120 or its supply line.

The truncated cones 65 and 70 take over during operation of the servo valve 5 the throttle function. After a first partial stroke of the valve member 10 (Frustum 65 is at least with a small part still in the passage bore 35 ) gives the truncated cone 65 only a small cross section free and leaves fluid from the control room 120 only slowly, what the nozzle needle 125 gives only a slow opening speed. This truncated cone 65 is suitable for pilot, pilot or post-injection. After a further partial stroke of the valve member 10 (not to the full stroke) is the truncated cone 65 no longer in the passage hole 25 but only the truncated cone 70 , which now releases a larger cross-section and thus the pressure in the control room 120 reduce faster, what z. B. for a Main injection is suitable. If the main injection is to be clocked, it is possible to reciprocate the extension between the first and second partial strokes in an oscillating manner. Helpful in such a variant is that the truncated cone 75 with the throttle bore 25 an at least approximate cylindrical cover 60 which can reduce the flow through the bore as close as possible to zero or almost zero. For this it is necessary that the truncated cone 65 at least approximately a barrel or cylindrical section 45 having. coverage 60 In this example, we mean that overlapping 60 the truncated cone 65 and the inner wall of the passage bore 25 (almost) touch. Here it makes sense the component elasticities of the valve body 15 in the area of the passage bore 25 (Expansion (comparatively large)) and the valve member 10 in the area of its truncated cone 65 (Compression (comparatively small)) to be considered (see also below).

In a further preferred embodiment of the invention, the truncated cone 65 one with the valve axis 80 parallel or at a preferably acute angle to this executed Flächenanschliff 40 by means of which it is possible the flow through the passage bore 25 set in addition dosed and the flow characteristic to give a defined slope (see also below). Are also possible several -. B. for a more even flow through the servo valve 5 also symmetrically arranged - Flächenanschliffe 40 , right up to a completely circumferential area 40 , The latter is z. B. interesting for the production of a single type of valve member 10 , which by means of a circumferential Flächenanschliffs 40 individually adaptable to his field of work, what the manufacturing cost per valve member 10 reduced.

In register nozzles, which are usually controlled by a register servo valve, it is also with the inventive design of the profile section 30 possible by a first partial stroke to slowly lower the pressure in a first control chamber for controlling a first nozzle needle, so as to achieve a slow opening of the first nozzle needle. This is particularly advantageous if z. B. only a very small amount of pre- or post-injection is to be metered and the nozzle needle to be closed well before reaching their stroke stop again. If the control chamber pressure collapsed abruptly, the nozzle needle would move with uncontrolled high speed immediately up to its stroke stop, making it impossible to dosing a small injection quantity.

Furthermore, although it may be necessary to slowly open the nozzle needle of the first stage (see above), then as soon as possible to add the second stage of the register nozzle by opening a second nozzle needle. In this case, it may be necessary for the concept that the pressure in the first control chamber must be lowered further in order to even achieve the force for opening the second stage, or not to exceed the maximum permissible voltage of the drive unit, in this case preferably a piezoelectric crystal. By appropriate design of the valve geometry (eg according to 3 and 4 ) is now lowered by a second partial stroke, the pressure in the control chamber of the first stage so far that the second stage can be opened. Ie. by a steep rise in the flow characteristic (see also below and characteristics 1 and 2 of the 5 ) ensures that the hydraulic force is reduced to the second nozzle needle so far that it can open at all, while a "slow" opening of the first nozzle needle is ensured by the "gentle" pressure reduction in Teilhubphase.

For a correct function of the servo valve 5 Depending on the operating point is a predetermined stroke of the valve member 10 and therefore a certain movement of the actuator necessary. This Aktautorbewegung results from a certain energy level, which is provided by a drive unit. This required energy level is mainly dependent on the valve seat diameter and the control chamber pressure. Especially at high system pressures opening and closing forces are necessary, which lead to elastic deformation of the valve parts and the drive unit (long piezoelectric crystal!). As a result, immediately after opening the servo valve 5 relax the elasticities present in the valve system and lift the valve member 10 lead to a larger valve lift than desired. Due to the small dimensions of the servo valve 5 and the low valve lifts, this effect can not be compensated by manufacturing tolerances.

However, this effect can be counteracted by taking into account the component elasticities in the valve opening operation and reducing the valve lift by the amount resulting from the elasticity degradation. Ie. the added by the elasticity degradation distance between the valve body 15 and valve member 10 must be deducted for the real stroke calculation of an idealized stroke without loss of elasticity in corresponding relation. This is advantageously done by reducing the Aktuatorhubs the drive unit, z. B. by lowering the energy level of the drive unit directly before, during or after lifting the valve member 10 ,

5 shows flowcharts 1 . 2 (Flow rate Q as a function of Ventilgliedhub h and execution of profile section 30 with through let drilling 25 ) of servo valves according to the invention 5 and flowcharts 3 . 4 of servo valves 5 according to the prior art. In particular Kennline 2 corresponds to the valve design according to 3 and 4 ,

In these two embodiments, the characteristics 1 and 2 each two distinct linear sections.

The first linear section of the characteristic 1 (starting at low lift and low flow rate and almost parallel to the stroke axis) results from an approximately fully cylindrical section 45 of the truncated cone 65 (in 3 and 4 within the passage hole 25 arranged) and thereby in the passage bore 25 provided very narrow annular gap extending in the direction of the passage bore 25 extends with almost constant gap width from top to bottom. This gap volume has approximately the shape of a hollow cylinder and extends along the cylindrical cover 60 ( 3 ). Will the valve member 10 just a little bit further from the passage hole 25 moved out, so the effective flow cross-section does not change or virtually no and the flow rate remains constant; This is particularly advantageous in the case of voltage fluctuations of the drive unit of the actuator, so that it can be ensured that the same opening cross-section always exists even with different voltages on the drive unit.

The. curve 2 in this section of the diagram, one reaches by the truncated cone 65 a Flächenanschliff 40 provides that is not carried out in parallel with respect to the valve member axis ( 3 ). When moving out of the valve member 10 opens the Flächenanschliff 40 a growing flow area, which is the slope of the curve 1 flat section increases and so to the characteristic 2 becomes.

The sudden onset, steep, almost linear increase in the two curves 1 and 2 from approx. 60-65% (characteristic 1 : 60%, characteristic 2 : 65%) of the full stroke results from the fact that the truncated cone 65 completely or almost completely from the passage bore 25 is moved out and a profile pin or the truncated cone 70 into the throttle bore 25 is in, which releases a larger flow area. The profile pin runs downwards (in the direction of the control room 120 ) conically, so that in a further moving out of the valve member 10 and therefore also the profile pin an ever larger flow area is free. Finally, the profile pin is completely out of the throttle bore 25 moved out, which releases the full flow area. This position of the valve member 10 Correctly corresponds to the full stroke of the valve member 10 ,

Likewise, more than two linear sections of the flow characteristic are possible by z. B. in the stepped section 30 of the 3 and the 4 provides further stages.

The approximately linear sections of the flow characteristic of the valve according to the invention 5 extend over a stroke difference of at least 10%, preferably at least 20%, in particular at least 35%, particularly preferably at least 50% of the full stroke of the valve member 10 , Furthermore, the linear portions of the flow characteristic extend over a flow rate difference of at least 10%, preferably at least 25%, in particular at least 45%, particularly preferably at least 70% of the maximum flow of the valve member 10 , In addition, after a stroke of 10% of the full stroke of the valve member 10 at most 20%, in particular at most 10%, preferably at most 5%, particularly preferably at most 3% of the maximum flow rate of the valve before. Furthermore, after a stroke of 60% of the full stroke of the valve member 10 at most 60%, in particular at most 30%, preferably at most 10%, particularly preferably at most 5% of the maximum flow rate of the valve before. However, the invention is not limited to the above embodiments, but may depending on the shape of the section 30 any characteristic curves of the valve 5 be generated.

By design of the profile section 30 is it possible flow characteristics of servo valves 5 "Compose". Each valve member stroke can by means of diameter design of the section 30 or in the embodiment according to the 3 & 4 be assigned by means of diameter design of the extension a certain flow area. An influence on the slope of the linear sections, but also the non-linear, is by means of (angle) Flächenanschliffs 40 adjustable over wide ranges.

Also, a decrease in the flow characteristic - by increasing the diameter at a portion of the section 30 - is possible.

Further is on similar Way an embodiment of the passage bore possible to a throttle effect to achieve. Here it may be advantageous if flow bore and the profiled section both have a particular configuration exhibit the desired in mutual interaction Realized flow cross sections.

One possible embodiment would be z. B. a cylindrical passage bore with a centrally arranged to the bore axis hollow ball space whose radius is greater than the bore radius. Within this bore is configured as a ball free valve member end back and forth. Preferably, the diameters of the passage bore and the ball are dimensioned at the valve member end so that a gap is provided between the two, the dimensions of which move in the one to two-digit micron range. This ball on the valve member end is now movable in the bore, that at least their equator can completely pass through the hollow spherical space. By means of this embodiment, it is possible to perform a pre-injection, main injection and post-injection within a single total stroke.

Claims (17)

Valve, in particular servo valve of a fuel injector, with an axially movable valve member ( 10 ) and a valve body ( 15 ), which has a passage bore ( 25 ) and a sealing seat ( 20 ), at which a sealing portion ( 35 ) a free end portion of the valve member ( 10 ) is sealingly seated in a closed position of the valve, characterized in that the free end portion of the valve member ( 10 ) in the closed position of the valve into the passage bore ( 25 ) or extending therethrough profiled section (FIG. 30 ), which within the passage bore ( 25 ) is positionable such that the profiled section ( 30 ) depending on its profile and on a stroke of the valve member ( 10 ) in the passage bore ( 25 ) opens a variable flow area. Valve according to claim 1, characterized in that the valve member ( 10 ) is directly or indirectly actuated by means of an actuator, in particular a piezoelectric actuator, which controls the valve member ( 10 ) moves partially and / or partially continuously between the closed position and an open position of the valve. Valve according to claim 1 or 2, characterized in that a flow through the valve by means of shaping the profile of the section ( 30 ) of the valve member ( 10 ) and / or the passage bore ( 25 ) is arbitrarily adjustable. Valve according to claim 3, characterized in that the section ( 30 ) of the valve member ( 10 ) and / or the passage bore ( 25 ) are configured such that at a first partial stroke of the valve member ( 10 ) a very narrow, in a subsequent partial stroke a larger and only at full stroke of the valve member ( 10 ) the maximum flow cross-section is opened. Valve according to claim 3 or 4, characterized in that the section ( 30 ) of the valve member ( 10 ) and / or asymmetrically shaped with respect to its axis of rotation. Valve according to one of claims 3 to 5, characterized in that the section ( 30 ) of the valve member ( 10 ) is at least partially cylindrical, conical, frusto-conical, ellipsoidal, spherical, barrel-shaped or at least partially configured with higher-order rotationally symmetric surfaces. Valve according to one of claims 3 to 6, characterized in that the section ( 30 ) of the valve member ( 10 ) and / or the passage bore ( 25 ) are configured such that at a certain position of the section ( 30 ) in the passage bore ( 25 ) between the inner wall of the passage bore ( 25 ) and the section ( 30 ) creates a substantially hollow cylindrical gap volume. Valve according to one of claims 3 to 7, characterized in that the profiled section ( 30 ) one of two substantially pointed truncated cones ( 65 . 70 ) composite extension, which preferably integrally at the free end of the valve member ( 10 ) is trained. Valve according to one of claims 3 to 8, characterized in that the section ( 30 ) of the valve member ( 10 ) a surface section ( 40 ) having. Valve according to claim 9, characterized in that the Flächenanschliff ( 40 ) is designed with an angle of inclination to the valve axis. Valve according to one of claims 1 to 10, characterized in that a in a partial lift of the valve member ( 10 ) resulting annular gap between the inner wall of the passage bore ( 25 ) and at the free end portion of the valve member ( 10 ) section ( 30 ) has a gap width in the micron range. Valve according to one of claims 1 to 12, characterized in that, for controlling the flow rate through the valve, an elastic component deformation taking place when the valve is opened and / or closed is determined during the determination of the partial lift of the valve member ( 10 ) is taken into account. Valve according to Claim 12, characterized in that, in order to take account of the component deformation when the valve is opened, immediately after the valve member has been lifted ( 10 ) from the sealing seat ( 20 ) the drive energy of a drive unit of the actuator is lowered. Valve according to one of claims 1 to 13, characterized in that the section ( 30 ) of the valve member ( 10 ) is configured in such a way and with the passage bore ( 25 ) of the valve body ( 15 ) like this cooperates, that when flowing through fluid a stroke-dependent flow characteristic of the valve has at least two at least approximately linear sections. Valve according to claim 14, characterized in that at least two of the linear sections the flow characteristic of the valve a different one Have slope. Injector, in particular for a diesel engine, having a valve according to one of Claims 1 to 15, the valve preferably being in the form of a servovalve ( 5 ) is used. Fuel injection system, in particular common-rail injection system, with an injector according to claim 16th