EP3055549B1 - Plunger/fluid-line arrangement, in particular control-plunger/control-bore arrangement - Google Patents

Description

The invention relates to a piston-fluid line arrangement, in particular a control piston control bore arrangement for an injector, in particular a fuel injector for a direct injection system of a motor vehicle. Furthermore, the invention relates to an injector, in particular a fuel injector for a direct injection system of an internal combustion engine.

The DE 10 2011 079 468 A1 discloses a piston fluid line arrangement, in particular a control piston control bore arrangement for an injector, in particular a fuel injector for a direct injection system of a motor vehicle, in which a piston of the piston-fluid line arrangement fitted or paired into a fluid line by means of a fluid passing through the fluid line hydraulically positioned sideways.

Stricter legal regulations regarding permissible pollutant emissions from internal combustion engines for motor vehicles make it necessary to achieve improved mixture preparation in the cylinders of internal combustion engines by means of fuel injectors. In current injectors, fuel injection is controlled by means of a nozzle needle which is slidably mounted in the injector and releases and re-closes an opening cross-section or one or a plurality of spray holes of a nozzle assembly of the injector in response to its stroke. A control of the nozzle needle, for example, by means of a piezoelectric actuator, which actuates the nozzle needle hydraulically or mechanically.

In order to reduce the pollutant emissions of the internal combustion engine and to keep its consumption as low as possible, it is desirable to maximize combustion within the Cylinder of the internal combustion engine to achieve. For good process control or control / regulation of combustion in the cylinders, it is necessary to be able to dose the fuel to be injected volumetrically and in terms of time as accurately as possible in order to maximize combustion and / or complete regeneration of a particulate filter at any given time To achieve motor vehicle, since torque requirements of the internal combustion engine are converted into injection quantities, which in turn with an injection period in Dependence of an injection pressure, a stroke of the nozzle needle and a geometry of the injector correlate.

A deviation of an actual injection quantity-a so-called shot-from a desired injection quantity of the injector always has a negative effect on combustion, that is to say the resulting pollutant emissions, and usually also consumption of the internal combustion engine. In particular, for direct injection injectors high demands on an accuracy of the injection quantities and a stability of a steel image under all operating conditions and over a lifetime of the injector away. This applies in particular with regard to small injection quantities in a multiple injection mode with the short injection intervals associated therewith and / or in a partial stroke mode of a nozzle needle.

In order to ensure the lowest possible Shot / Shot scattering in a modern injector, it is necessary to maintain a fluid pressure in a control chamber of the injector as accurately as possible as a function of a rail pressure during an injection break. This pressure arises as a function of flow resistance in the individual leakage paths (inflow and outflow) of the injector. Since a flow resistance of a control piston (piston) of the injector, which is in a control bore (fluid line) with a defined fit is dependent on a positioning of the piston (centric, eccentric, tilted) in the control bore, there is an impact on one adjusting control chamber pressure and thus to an injection quantity. Stochastic fluctuations of this pressure due to changing positioning of the control piston in the control bore lead to increased stochastic fluctuations of the injection quantities, d. H. to increased shot / shot spreads.

It is an object of the invention to reproducibly adjust a fluid pressure in a fluid space by means of a piston in a fluid line, wherein a position of the piston in the fluid line is to be set reproducibly. Especially It is an object of the invention to set or maintain a fluid pressure in a control chamber of an injector, in particular a fuel injector, as accurately as possible during an injection pause as a function of a rail pressure. So z. B. Shot / Shot scattering, especially for a hydraulically directly driven injector can be improved. Furthermore, it is an object of the invention to provide a correspondingly improved injector.

The object of the invention is by means of a piston-fluid line arrangement, in particular a control piston control bore arrangement for an injector, in particular a fuel injector for a direct injection system of a motor vehicle, according to claim 1; and by means of an injector, in particular a fuel injector for a direct injection system of an internal combustion engine, according to claim 11 solved. Advantageous developments, additional features and / or advantages of the invention will become apparent from the dependent claims and the following description of the invention.

The piston-fluid line arrangement according to the invention comprises a piston fitted and / or paired into a fluid line which can be hydraulically positioned sideways by a fluid passing through the fluid line, wherein according to the invention a geometry of the piston and / or a geometry of the fluid line is configured or are that the piston is positioned eccentrically and / or positioned by the fluid in the fluid line. The geometry of the piston is preferably a secondary geometry, wherein a primary geometry of the piston is preferably cylindrical. Likewise, the geometry of the fluid line is preferably a secondary geometry, wherein a primary geometry of the fluid line is also preferably cylindrical. - The injector according to the invention comprises a piston-fluid line arrangement according to the invention, in particular a control piston control bore arrangement according to the invention.

In embodiments of the invention, the preferred secondary geometry of the piston and / or the preferred secondary geometry of the fluid conduit is configured such that a centerline of the piston is positionable and / or positioned by the fluid substantially parallel to a centerline of the fluid conduit. Furthermore, the geometry (s) may be selected such that a flow of the fluid between the piston and the fluid line (sealing gap) is greater than a flow in the case of a concentric position of the piston in the fluid line. In this case, it is possible to set the flow of the fluid between the piston and the fluid line as a substantially maximum flow. In this case, the piston assumes a substantially highly eccentric position relative to the fluid line. Such an embodiment may be advantageous in some applications wherein a maximum minimum flow rate for a given fit or pairing is adjusted by the piston and the fluid line.

In embodiments of the invention, the preferred secondary geometry of the piston and / or the preferred secondary geometry of the fluid conduit is or are configured such that in a sealing gap between a lateral surface of the piston and an inner surface of the fluid line an asymmetric pressure distribution of the fluid is adjustable and / or is set. Furthermore, the geometry (s) may be selected such that a fluid path is provided in the lateral surface of the piston and / or the inner surface of the fluid line, by means of which the asymmetrical pressure distribution of the fluid in the sealing gap is adjustable and / or adjusted.

In addition, the geometry (s) may be selected such that the fluid path is provided in the lateral surface of the piston and / or the inner surface of the fluid line such that a lateral force can be exerted and / or exerted on the piston by means of the fluid. - The asymmetric pressure distribution of the fluid in the sealing gap has the lateral force of the fluid to the piston result, the side force to attack on the piston so, ie the asymmetric pressure distribution on the piston should be set up so that the center line of the piston with respect to the center line of the fluid line is set up parallel and parallel.

According to the invention, the fluid path can be designed in such a way that the piston is permanently securely positioned in an eccentric position over relevant operating states and the flow of the fluid through the sealing gap is comparatively small. For a given pressure difference on the piston, it is primarily desired to have a flow that is as constant as possible and, secondarily, the lowest possible flow of fluid through the sealing gap. A larger eccentricity of the piston also means a larger flow of fluid through the sealing gap, therefore, it is preferable to aim for a safe eccentric position, in which the flow of the fluid through the resulting sealing gap is comparatively small. Ie. it is a comparatively small, but over time geometrically constant eccentric position of the piston in the fluid line sought.

According to the invention, the fluid path can be provided on / in the piston and / or on / in the fluid line. The following explanations relate mainly to the piston and are, where appropriate, also applicable to the fluid line. Thus, the fluid path on / in the piston can be arranged such that it can be brought into fluid communication with a high-pressure side or a low-pressure side of the piston. In this case, the fluid in the fluid path pushes the piston away from an opening of the fluid path on / in the piston, or the fluid in the sealing gap presses the piston toward an opening of the fluid path on / in the piston. - Under the low pressure side should be understood an end region of the piston, in which there is a lower fluid pressure than on the high pressure side of the piston. This pressure difference can be only a few bar, which can certainly prevail on the low pressure side, a fluid high pressure.

Ie. in the first case, ie the fluid connection of the fluid path with the high-pressure side of the piston, that the fluid in the

Fluid path pushes the piston away from the opening of the fluid path in the direction of a radially opposite region of the inner surface of the fluid line. And for the second case, ie the fluid connection of the fluid path with the low-pressure side of the piston, the fluid in the sealing gap presses the piston in the direction of the opening of the fluid path to a region of the inner surface of the fluid line directly opposite the opening.

In preferred embodiments of the invention, the fluid path can have a recess on / in the piston, wherein the recess is in particular a groove or facet, which extends in sections in the circumferential direction and / or in sections in the longitudinal direction of the piston. A bottom of the recess may be flat or curved, d. H. the bottom of the recess has z. B. a radius. Such embodiments are relatively easy to be transferred to the fluid line. Furthermore, the fluid path can have a fluid connection from an interior and an exterior of the piston, wherein the fluid connection is in particular a bore, preferably a through-bore, and / or an intersection, preferably an inner and outer recess of the piston.

In embodiments of the invention, the fluid path outside the piston may have the opening, a circumferential groove, a circumferential facet, a longitudinal groove and / or a longitudinal facet. Further, the fluid path may include at least one bore from an outside of the piston to a piston interior. In addition, the fluid path can have an intersection of an outer recess with an inner recess and / or a recess on a longitudinal end portion of the piston. - According to the invention, the piston may be formed as a control piston, a pin, a control pin or a leakage pin. When using a fuel, the fluid is preferably a diesel or gasoline fuel.

According to the invention, it is possible to adjust a fluid pressure in a fluid space by means of a reproducible piston position in a fluid line. This will be a position of Pistons set in the fluid line by means of a geometry of the piston and / or the fluid line. The invention is well applicable to injectors, in particular fuel injectors, wherein a fluid pressure in a control chamber of the injector is well adjustable or can be maintained during an injection pause. Ie. it improves the shot / shot scattering of the injector. Furthermore, a dispersion in a mass production based on an injector function is reduced, and a proportion of those injectors that do not meet required tolerances in their injection quantities, can be reduced. Thus, an expense of necessary rework can be reduced. This affects individually and in total in a reduction of the manufacturing costs.

The invention is explained in more detail below with reference to embodiments with reference to the accompanying drawings. Elements or components which have an identical, univocal or analogous configuration and / or function are identified by the same reference numerals in different figures (FIG. 1) of the drawing.

In the schematic Fig. The drawing show the Fig. 1 a longitudinal side view of an injector according to the invention for a common rail injection system of an internal combustion engine, which is shown centrally and centrally cut below; the Fig. 2 a centrally cut, broken away top and bottom, detailed longitudinal side view of a control assembly of the injector Fig. 1 , with a hydraulic direct drive of a nozzle needle; and the Fig. 3 to 5 a first, the Fig. 6 to 8 a second, the Fig. 9 to 11 a third, the Fig. 12 to 14 a fourth, the 15 to 17 a fifth, the Fig. 18 to 20 a sixth, and the Fig. 21 to 23 a seventh embodiment of a piston-fluid line arrangement according to the invention, in particular a control piston control bore arrangement according to the invention for an injector. A respective first Fig. The embodiments is a sectional side view and a respective second Fig. A sectional plan view of a control plate of the injector. The respectively Third Fig. The embodiments is a perspective view of a control piston of the injector. Furthermore, the show FIGS. 24 and 25 two embodiments of an application of the invention to a fluid line.

The invention is explained in more detail below with reference to a piezoelectrically operated common rail diesel injector 1 for an internal combustion engine (see FIG. Fig. 1 ). However, the invention is not limited to such diesel injectors 1, but can, for. B. also be applied to pump-nozzle injectors or gasoline injectors with a single or multi-part nozzle needle. For gasoline injectors typical names can be found in the list of reference numerals. An injectable fluid may be a fuel, it is of course possible by means of an injector 1 according to the invention, another fluid such. Water, an oil or any other process fluid; ie the injector 1 according to the invention is not limited to the automotive industry.

The Fig. 1 shows the injector 1 substantially in a sectional view, wherein the injector 1 comprises a nozzle assembly 10 and an injector assembly 50. The nozzle assembly 10 and the Injektorbaugruppe 50 are fluid-tight by means of a nozzle lock nut 60 together. The injector assembly 50 has an injector body 500, in which an actuator 510 is provided, which is preferably designed as a piezoelectric actuator 510. However, an electromagnetic actuator is also applicable. In the present example, the piezoactuator 510 drives a one-piece, preferably integral, nozzle needle 110 hydraulically directly (see also FIG Fig. 2 ). The nozzle needle 110 may also be formed in two or more parts and / or be configured to open outwardly in the injector 1.

The injector body 500 has a high-pressure-side fluid connection (not illustrated) for the fuel to be injected, the fluid connection being in fluid communication with a high-pressure bore 502 formed in the injector body 500. Through the high-pressure side fluid connection the injector 1 is hydraulically connectable to a high-pressure fluid circuit (not shown). The high-pressure bore 502 supplies the nozzle assembly 10 and thus a nozzle chamber 102 of the injector 1 with fuel under high pressure, z. B. a so-called rail pressure (common rail system). In the nozzle chamber 102, during an operation of the injector 1, there is essentially always an actual high or maximum pressure.

The nozzle assembly 10 has a nozzle body 100 with at least one spray hole (not shown) in its nozzle 104 and the nozzle chamber 102, wherein the nozzle needle 110 is arranged displaceably in the nozzle chamber 102 and stored in sections. The nozzle needle 110 is pressed via an energy storage 114, preferably a nozzle needle spring 114, in the direction of its nozzle needle seat inside in the nozzle 104 in order to be securely closed even in an electrically non-energized state of the piezoelectric actuator 510. Depending on a control of the piezoelectric actuator 510, the nozzle needle 110 is either pressed into its nozzle needle seat or moves away from the nozzle needle seat, whereby fuel can be injected.

The nozzle assembly 10 further accommodates a control assembly 20 located between the nozzle body 100 and the injector assembly 50 for actuating the nozzle needle 110 based on elongation of the piezoactuator 510 in response to its energy or charge, that is, an electrical voltage applied thereto. - The Fig. 2 shows the components of the control assembly 20 for a direct hydraulic coupling by an elongation movement of the piezoelectric actuator 510 and thereby caused movement of the nozzle needle 110. The piezoelectric actuator 510 has for this purpose a bottom plate 512 with a preferably one-piece Betätigungsfortsatz in direct mechanical contact with a transmission pin 214 is fitted and / or paired with a very small clearance in a pin bore 212 of an intermediate plate 210 of the control assembly 20.

A mating clearance of the transmission pin 214 in the pin bore 212 is chosen to be so small, e.g. B. about 1 micron, that even at a high Rail pressure of up to over 2,500 bar only a small fuel leakage at the transfer pin 214 occurs. The pin bore 212 connects a first control chamber 22, which is also referred to as a piston control chamber 22 and in which a slightly lower fuel pressure than the actual rail pressure prevails, with a leakage chamber 52 of the injector 1, which is preferably in an ambient pressure in permanent fluid communication. The leakage chamber 52 is preferably in fluid communication with a leakage connection 504 of the injector 1. At the transfer pin 212 there is a comparatively large pressure difference z. B. assuming a maximum pressure of 2,500 bar and a closed injector 1 may well exceed a value of 2,450 bar.

The first control chamber 22 communicates through a connecting bore 14 in a section of the control assembly 20 with a second control chamber 12, the so-called needle control chamber 12, preferably in permanent fluid communication. In the second control chamber 12, just as in the first control chamber 22, a slightly lower fuel pressure prevails than the rail pressure, wherein the pressures in the control chambers 12, 22 are substantially the same, at least when the injector 1 is closed. In the connecting bore 14, a fluid throttle (not shown) may be provided, which is preferably formed in a separate plate 230 of the control module 20.

A stroke (elongation) of the piezoelectric actuator 510 is transmitted by means of the transmission pin 214, which is also referred to as leakage pin 214, to a control piston 300, which is fitted and / or paired into a control bore 400 of a control plate 220 of the control module 20. The transmission pin 212 engages on / in the first control chamber 22 at an upper end face of the control piston 300, wherein the control piston 300 is supported on an inner end face by an energy storage device 224, preferably designed as a spiral spring 224. At the inner end face and an underside of the control piston 300 there is preferably substantially rail pressure, this area preferably is in permanent fluid communication through a communication bore 232 with the nozzle space 102.

In the present examples, the control piston 300 is designed as a sleeve 300 which is closed on the upper side (side of the first control chamber 22) and in the interior 340 of which the spring element 224 for returning the control piston 300 protrudes. It is of course possible to form the control piston 300 as a solid cylinder, in which case the spring element 224 acts on an underside of the control piston 300, and the spring element 224 z. B. may be stored in a bore in the plate 230. Mixed forms between the illustrated sleeve-shaped control piston 300 and a control piston 300 as a solid cylinder are of course possible.

The second control chamber 12 is formed by an end face of an upper longitudinal end portion 112 of the nozzle needle 110, the so-called needle piston 112, a wall of a needle bore 122 in an upper guide 120 of the nozzle needle 110, preferably a nozzle needle sleeve 120, and a lower end face of the plate 230. The needle piston 112 of the nozzle needle 110 is facing away from a nozzle needle tip of the nozzle needle 110 or the nozzle 104 of the nozzle body 100. - This briefly set forth embodiment of the injector 1 is not restrictive to understand. Of course, the invention is applicable to a variety of other embodiments of injectors.

By a movement of the control piston 300 due to a stroke of the piezoelectric actuator 510 (by means of the transmission pin 214), a pressure drop is generated in the first control chamber 22, which via the connection bore 14 and possibly delayed by the optional fluid throttle in the plate 230 on the upper end face of the nozzle needle 110 is transmitted in the second control room 12. If this pressure drop exceeds a certain value, the nozzle needle 110 opens and there is an injection of fuel (shot). A stroke of the nozzle needle 110 can be controlled or regulated by opening the nozzle needle 110 via a variation of the stroke of the piezoactuator 510. The stroke of the piezo actuator 510 can be changed by a variation of its intrinsic electrical energy.

When discharging the piezoelectric actuator 510, this shortens. By acting on the inner end face (underside) of the control piston 300 rail pressure from the nozzle chamber 102 together with the also acting in this direction force of the spring element 224, the control piston 300 is pushed back to its original position, which is determined by a position of the transmission pin 214 , As a result, the nozzle needle 110 is moved back into its closed position corresponding to the movement of the piezoactuator 510 and fuel injection is terminated. The nozzle needle spring 114 then securely holds the nozzle needle 110 closed / seated in the nozzle 104 of the nozzle body 100.

The aim of the invention is to ensure the lowest possible shot / shot scattering of the injections. In this case, it is necessary to adjust the fluid pressure in the control chamber 12, 22 as precisely as possible during an injection pause as a function of the rail pressure and to make it reproducible. This reproducible behavior can then be taken into account when controlling the piezoactuator 510. An influence on a self-adjusting fluid pressure in the control chamber 12, 22 have to a large extent the control piston 300 (in general: piston 300) and the control bore 400 (in general: fluid line 400). In this case, in addition to a specified tolerance-prone size of a sealing gap 222 between the control piston 300 and the control bore 400, a position of the control piston 300 in the control bore 400 of importance, because changing positions of the control piston 300 in the control bore 400 lead to increased shot / shot scattering.

Possible positions of the control piston 300 in the control bore 400 are substantially a concentric, an eccentric and a tilted position. Due to these different positions of the control piston 300, the flow resistances in the control bore 400 change due to a position resulting from the respective position Gap geometry significant. The flow of fluid through the sealing gap 222 at a maximum eccentric position of the control piston 300 is increased by a factor of about 2.5 in comparison to its concentric position. At a maximum tilted position of the control piston 300, this factor is only about 0.5. Ie. Through the sealing gap 222, at a maximum eccentric position of the control piston 300, a fivefold amount of fluid per unit of time can flow than at a maximum tilted position (in the case of an injector 1). This has a significant effect on the adjusting in the injection pauses pressures in the control chambers 12, 22, in particular the first control chamber 22nd

The solution according to the invention for this problem consists in using a geometry of the control piston 300 (cf. Fig. 3 to 23 ) and / or a geometry of the control bore 400 (see. FIGS. 24 and 25 ) to influence a position of the control piston 300 in the control bore 400 influence. This is preferably done in such a way that primarily a safe eccentric and no concentric and no tilted position of the control piston 300 in the control bore 400 is sought. Secondarily, in this safe eccentric position, a flow of the fluid (here: fuel) through a self-adjusting sealing gap 222 should be comparatively low. - The corresponding geometry or the corresponding geometries are chosen such that a center line 302 of the control piston 300 is set parallel to a center line 402 of the control bore 400, wherein the two center lines 302, 402 are not aligned, but spaced from each other, in particular not maximum spaced from each other, are.

According to the invention, the control piston 300 is modified on its lateral surface 304 and / or the control bore 400 on its inner surface 404 such that a resultant lateral force on the control piston 300, which ensures an eccentric preferred position of the control piston 300 in the control bore 400. This results in stochastic fluctuations in the injection quantities even at high rail pressures at a relatively low level. Such a modification is preferably performed by a fluid path 310, 410 on / in the control piston 300 and / or on / in the control bore 400 which opens on the control piston 300 (opening 312, 412).

The fluid path 310, 410 can be a groove, z. B. a circumferential groove and / or a longitudinal groove, a facet, z. B. a peripheral facet and / or a Längsfacette, a Wegnehmung and / or a fluid connection, such as a bore, a through-bore and / or an intersection, etc., or any combination thereof. All of these terms are to be subsumed in accordance with this specification under the term recess, in the sense of deviation from a primary geometry of the control piston 300 and the control bore 400. The primary geometry of the control bore 400 and the control piston 300 is the shape of a (hollow) cylinder or a (hollow) cone. The control piston 300 may be a part or section of another component, for. B. a needle piston 112 of a nozzle needle 110, a valve body or a part or portion thereof, etc. This applies analogously to the control bore 400, which does not necessarily have to be set up in the control plate 220.

An opening 312, 412 of the fluid path 310, 410 constituted by one or a plurality of recesses 320, 322; 422, 426, is designed such that the center lines 302, 402 of the control piston 300 and the control bore 400 are substantially parallel to each other. In this case, it is particularly preferred that the lateral force generated by the fluid passing through the opening 312, 412 (as a result of the asymmetric pressure distribution due to the opening 312, 412) acts on the control piston 300 substantially longitudinally on the control piston 300, so that substantially no tilting moment on Control piston 300 is created. This can have the consequence that the opening 312, 412 itself is not provided centrally on the control piston 300 (see. Fig. 5 ), since the pressure conditions in the sealing gap 222 change from the high to the low pressure side, wherein the sealing gap 222 acts as a fluid throttle.

According to the invention, the fluid path 310, 410 of the control piston 300 and / or the control bore 400 with the high-pressure side (FIG. 3 to 24 ) or with the low-pressure side ( Fig. 25 ) are in fluid communication. The fluid communication of the fluid path 310, 410 with the low pressure side is a hydraulic reversal of the fluid communication of the fluid path 310, 410 with the high pressure side. In the first case, an overpressure at the opening 312, 412 on the control piston 300 ensures a parallel offset of the control piston 300 relative to the control bore 400. And in the second case, a negative pressure at the opening 312, 412 on the control piston 300 for a parallel offset of the control piston 300 opposite the control bore 400.

The following is first with reference to the Fig. 3 to 23 a general embodiment of the invention explained in more detail. In a connection thereto, the - of course not conclusive - seven embodiments of the invention are briefly explained, which relate to the control piston 300 and a piston 300. However, these explanations are analogous to the control bore 400 and a fluid line 400 transferable, depending on whether this seems reasonable. See the FIGS. 24 and 25 showing two embodiments of the invention in which the inventive idea is applied to the control bore 400 and the fluid line 400, respectively. In particular one sees in the Fig. 25 a fluid path 410 in fluid communication with the low pressure side (first control chamber 22). This is intended to make it clear that any fluid paths 310 of the control piston 300 can also be hydraulically connected to the low-pressure side (see above).

An essential design feature is that on / in the lateral surface 304 of the control piston 300 on one side one or a plurality of recesses 320 - fluid path 310 or a portion thereof - are introduced in possibly different geometries. These recesses 320 lead to the asymmetrical pressure distribution in the sealing gap 222, so that the resulting lateral force arises, which brings the control piston 300 in its eccentric preferred position. - Since a piston interior 340 and a bottom of the control piston 300 with substantially the rail pressure of the injector 1, a pressure prevails in the fluid path 310 substantially at a level of the rail pressure.

On one of the opening 312 of the fluid path 310 on the control piston 300 opposite side of the sealing gap 222 of the fluid pressure drops over an entire length of the sealing gap 222 from the rail pressure to the fluid pressure of the first control chamber 22. The different pressure profile along the sealing gap 222 in the longitudinal direction of the control piston 300 between one side of the opening 312 of the fluid path 310 and a side facing away from this provides the above-mentioned resulting lateral force on the control piston 300.

A width (circumferential direction of the control piston 300) and height (longitudinal direction of the control piston 300) and an axial position of the opening 312 determine the hydraulic lateral force on the control piston 300. An advantageous and possibly 'optimal' design for the injector 1 provides a hydraulic lateral force which permanently positions eccentrically the control piston 300 (the side force is higher than a sum of possible 'disturbing' forces, such as a lateral force from the spring element 224), whereby the lateral force on the control piston 301 is preferably comparatively small. especially minimal, is or remains.

In the in the Fig. 3 to 5 shown first embodiment of the invention as a recess 320 in the circumferential and longitudinal direction of the control piston 300 extending groove 324 in the lateral surface 304 of the control piston 300 is introduced (outer recess 320). The circumferential groove 324 passes through a fluid connection 330, in particular a through-bore 332, in fluid communication with the piston interior 340, which preferably radially connects a bottom of the circumferential groove 324 with the piston interior 340. The bottom of the circumferential groove 324 may, as in Fig. 4 to see, have a radius of z. B. is greater than that of the control piston 300. Of course, the floor can also be level (cf. Fig. 13 ). A boundary of the circumferential groove 324 on the lateral surface 304 forms the opening 312 of the fluid path 310.

In the in the Fig. 6 to 8 illustrated second embodiment of the invention, instead of the circumferential groove 324 in the first embodiment, two fluid connections 330, in particular two through holes 332, in a wall of the control piston 300, preferably in the radial direction, introduced. The through holes 332 are located on one side of the control piston 300, and an angle of their center lines is preferably less than 120 °, in particular less than 90 ° and particularly preferably less than 45 °. The boundaries of the through-bores 332 on the lateral surface 304 together form the opening 312 of the fluid path 310. It is, of course, possible to provide only one or a plurality of through-bores through the wall of the control piston 300.

In the in the Fig. 9 to 11 illustrated third embodiment of the invention, the fluid path 310 comprises an outer recess 320 which is formed as a longitudinal facet 326 or longitudinal groove 326. Here, a surface 326 is ground or introduced to the control piston 300 over a certain length and width (circumferential direction of the control piston 300), which to the side of the rail pressure but z. B. also to the side of the first control chamber 22 (not shown, see FIG. Fig. 25 ) is open. A bottom of the longitudinal facet 326 or longitudinal groove 326 may, as in Fig. 10 to see, to be just, but also a radius analogous to Fig. 4 can be applied. A boundary of the longitudinal groove 326 or longitudinal facet 326 on the lateral surface 304 forms the opening 312 of the fluid path 310.

In the in the Fig. 12 to 14 shown fourth and in the in the 15 to 17 illustrated fifth embodiment of the invention, the fluid path 310 in each case from the side of the rail pressure of the control piston 300 has a narrow outer recess 320 which is formed as a Längsverbindungsnut 326 in the lateral surface 304 of the control piston 300. In the direction of the side of the first control chamber 22, the respective longitudinal connection groove 326 opens into an outer recess 320 which is designed in each case as a circumferential groove 324. A limitation of the circumferential groove 324 and with a small proportion a limitation of Längsverbindungsnut 326 on the lateral surface 304 together form the opening 312 of the fluid path 310th

The fourth embodiment is characterized in that a bottom of the circumferential groove 324 is flat ( Fig. 13 ), whereas in the fifth embodiment, a bottom of the circumferential groove 324 has a radius ( Fig. 16 ), which in turn may be larger than that of the control piston 300. Further, the circumferential groove 324 of the fifth embodiment covers a larger area outside of the control piston 300 than the circumferential groove 324 of the fourth embodiment. In the first case, the circumferential groove 324 covers approximately 90 ° and in the second case approximately 30-45 °. Further, the Längsverbindungsnut 326 may not be as deep, equal deep or deeper worked into the wall of the control piston 300 as the circumferential groove 324 in the adjacent area.

In the in the Fig. 18 to 20 illustrated sixth embodiment of the invention, the fluid path 310 includes an outer recess 320, which is formed as a circumferential groove 324. A bottom of the circumferential groove 324 in turn has a radius (see above), but in turn may be flat. The bottom of the circumferential groove 324 is in fluid communication with the piston interior 340 via an intersection 334 formed as a fluid connection 330. The intersection 334 is produced by a longitudinal groove 322, which is constituted as an internal recess 322, in the piston interior 340. Ie. the fluid communication 330 of the rail side circumferential groove 324 is made by the intersection 324 with the longitudinal groove 322 in the longitudinal direction of the spool 300 on an inner side of the spool 300. A boundary of the circumferential groove 324 on the lateral surface 304 forms the opening 312 of the fluid path 310.

In the in the Fig. 21 to 23 6, the fluid path 310 comprises a recess 328 or a recess 328 of a wall of the control piston 300, ie a piston shaft of the control piston 300 is shortened on one side over a specific circular segment. A limitation of Wegnehmung 328 on the lateral surface 304 forms the opening 312 of the fluid path 310th

Of course, these exemplary embodiments of the invention may also be applied to control pistons 300 which are not hollow drilled. In such a case, if necessary, a preferably small bore must be introduced into the control piston 300. Furthermore, these features can be applied to other mating and / or mating games in the injector 1, z. B. on the transmission pin 214 in the pin bore 212, to the nozzle needle 110 in the nozzle needle sleeve 120, etc., are applied, which in particular a leakage balance (inflow equal inflowing) and thus also affect a resulting pressure in the control chamber 12, 22. Furthermore, the invention is generally applicable to hydraulic coupling elements 300, i. H. the control piston 300 is formed as a hydraulic coupling element 300.

In the following, two exemplary embodiments of the invention are briefly explained, wherein the respective recess 422 is not provided on / in the control piston 300 but on / in the inner surface 404 of the control bore 400 (fluid line 400).

When in the Fig. 24 illustrated eighth embodiment of the invention, the fluid path 410 of the control bore 400 comprises an inner recess 422, which is formed as a longitudinal facet 426 or longitudinal groove 426. In this case, a surface 426 or recess 426 is ground or introduced into the inner surface 404 of the control bore 400 over a certain length and width (circumferential direction of the control bore 400), which is open to the side of the rail pressure. However, this can also be to the side of the first control chamber 22 (not shown, cf. Fig. 25 ) be open. A bottom of the longitudinal facet 426 or longitudinal groove 426 may be as shown in FIG Fig. 10 to see, to be just, but also a radius analogous to Fig. 4 can be applied, wherein the radius is preferably smaller than that of the control bore 400. A boundary of the longitudinal facet 426 or longitudinal groove 426 on the inner surface 404 forms the opening 412 of the fluid path 410 of the control bore 400 on the control piston 300.

When in the Fig. 25 9 illustrated ninth embodiment of the invention, the fluid path 410 of the control bore 400, an inner recess 422, which is formed as a narrow longitudinal groove 426 and the side of the first control chamber 22 is open. A limitation of the longitudinal groove 426 on the inner surface 404 essentially forms the opening 412 of the fluid path 410 of the control bore 400 on the control piston 300. In an operation of the injector 1, there is essentially a fluid pressure of the low-pressure side or the first control space 22 in the longitudinal groove 426 Inner recess 422 is in such a way, in particular in the longitudinal direction of the control bore 400 running established that results in an asymmetric pressure distribution of the fluid on the control piston 300, wherein the control piston 300 is sucked in the direction of the opening 412 of the fluid path 410 or from one of these opposite side of the fluid pressure is pressed in the sealing gap 222.

Such hydraulically reversed embodiments of the invention are generally applicable. Here, the pressure conditions on the control piston 300 in the radial direction of the control piston 300 at least qualitatively reverse. Ie. a pressure and a suction side on the control piston 300 change positions. For the embodiments one to seven of the invention this means that the fluid path 310 of the control piston 300 is open to the low pressure side and opens in the sealing gap 222 on the control piston. Of course, a fluid connection to the piston interior 340 is to be avoided.

A simple, not shown embodiment of the invention is a pressure channel through a solid cylinder designed as a control piston 300. Here, z. B. two in the control piston 300 blind holes arranged. One bore extends axially from the low pressure side into the control piston 300 and the other radially extends toward and intersects this first bore within the control piston 300. There then exists in the injector 1, a pressure channel from the low pressure side on one side in / on the sealing gap 222 between the control piston 300 and the control bore 400. - This embodiment is of course hydraulically reversible, the first blind hole instead of coming from the low pressure side, now from the High pressure side is set in the control piston 300. In a fully rotationally symmetrical control piston 300, this can simply be turned over to get from this embodiment to the other embodiment.

LIST OF REFERENCE NUMBERS

1

Injector, Fuel Injector, Common Rail / Piezo Fuel Injector, Injector Fuel Injector, Diesel Injector, Gasoline Injector

10

Nozzle assembly, injection module

12

second control room, needle control room

14

Connection bore / pipe between first 22 and second control room 12

20

Control assembly of the nozzle assembly 10 for driving the nozzle needle 110th

22

first control room, piston control room

50

Injector assembly, drive module

52

leakage chamber

60

Nozzle tension nut, valve clamping nut

100

nozzle body

102

Nozzle space, nozzle bore

104

Nozzle, injector, valve

110

Nozzle needle, injection needle, possibly two- / multi-part, opening inwards or outwards

112

upper longitudinal end portion of the nozzle needle 110, needle piston, the nozzle 104 and a valve of the injector 1 facing away

114

Energy storage, spring element, coil spring, compression spring, nozzle needle spring, injection needle spring for mechanical bias of the nozzle needle 110th

120

(upper) guide of the nozzle needle 110, nozzle needle sleeve

122

needle bore

210

intermediate plate

212

lingually

214

Transmission pin, leakage pin

220

control plate

222

Sealing gap between piston 300 and fluid line 400

224

Energy storage, spring element, coil spring, compression spring for bias of the piston 300

230

plate

232

connecting bore

300

Piston, control piston, hydraulic coupling element

302

Centerline of the piston 300

304

Lateral surface, lateral surface, shell side of the piston 300

310

Fluid path on / in the piston 300

312

Opening of the fluid path 310 on the piston 300

320

(outer) recess, outer recess

322

(inner) recess, inner recess

324

Groove, facet, circumferential groove, peripheral facet, recess

326

Groove, facet, longitudinal groove, longitudinal facet, recess

328

Removal, recess

330

Fluid connection between the inside and the outside of the piston 300, recess

332

Bore, through-hole, fluid connection, recess

334

Intersection, fluid connection, recess

340

Piston interior, interior

400

Fluid line, control bore, piston bore

402

Centerline of the fluid line 400

404

Inner surface, inner surface, inner side of the fluid line 400

410

Fluid path on the fluid line 400 or on / in inner surface 404th

412

Opening of the fluid path 310 on the piston 300

422

(inner) recess, inner recess

426

Groove, facet, longitudinal groove, longitudinal facet, recess

500

Injector body, injector housing with high pressure line 502 to the nozzle chamber 102

502

High pressure line / bore in fluid communication with the nozzle chamber 102 through the control assembly 20 therethrough

504

Leckageanschuss

510

Actuator, piezo actuator, electromagnetic actuator

512

Bottom plate of the actuator 510 preferably with actuating extension for transmission pin 214th

Claims (11)

1. Piston-fluid line arrangement, in particular control piston-control bore arrangement (300/400) for an injector (1), in particular a fuel injector (1) for a direct injection system of a motor vehicle, wherein
   a piston (300), which is fitted in or paired with a fluid line (400), of the piston-fluid line arrangement (300/400) can be positioned sideward hydraulically by way of a fluid passing through the fluid line (400), characterized in that
   a geometry of the piston (300) and/or a geometry of the fluid line (400) are/is configured such that the piston (300) can be positioned, and is positioned, eccentrically in the fluid line (400) by the fluid.
2. Piston-fluid line arrangement according to Claim 1, characterized in that the geometry of the piston (300) and/or the geometry of the fluid line (400) are/is configured such that
   a centerline (302) of the piston (300) can be positioned, and is positioned, substantially parallel to a centerline (402) of the fluid line (400) by the fluid; and/or
   a throughflow of the fluid between the piston (300) and the fluid line (400) is greater than a throughflow in the case of a concentric position of the piston (300) in the fluid line (400).
3. Piston-fluid line arrangement according to Claim 1 or 2, characterized in that the geometry of the piston (300) and/or the geometry of the fluid line (400) are/is configured such that
   an asymmetrical pressure distribution of the fluid can be set, and is set, in a sealing gap (222) between a shell face (304) of the piston (300) and an internal face (404) of the fluid line (400);
   in the shell face (304) of the piston (300) and/or the internal face (404) of the fluid line (400), there is provided a fluid path (310) by way of which the asymmetrical pressure distribution of the fluid in the sealing gap (222) can be set and is set; and/or
   in the shell face (304) of the piston (300) and/or the internal face (404) of the fluid line (400), the fluid path (310) is provided such that a sideward force can be exerted, and is exerted, on the piston (300) by way of the fluid.
4. Piston-fluid line arrangement according to one of Claims 1 to 3, characterized in that the fluid path (310) is formed such that the piston (300) is securely positioned in an eccentric position and, in this case, the throughflow of the fluid through the sealing gap (222) is relatively low.
5. Piston-fluid line arrangement according to one of Claims 1 to 4, characterized in that the fluid path (310) on/in the piston (300) is configured such that it can be placed in fluidic communication with a high-pressure side or with a low-pressure side of the piston (300); wherein
   the fluid in the fluid path (310) pushes the piston (300) away from an opening (312) of the fluid path (310) on/in the piston (300), and/or the fluid in the sealing gap (222) pushes the piston (300) toward an opening (312) of the fluid path (310) on/in the piston (300).
6. Piston-fluid line arrangement according to one of Claims 1 to 5, characterized in that the fluid path (310) has a recess (320, 322) on/in the piston (300), wherein
   the recess (320, 322) on/in the piston (300) is in particular a groove (324, 326) or facet (324, 326) which runs in a circumferential direction and/or longitudinal direction of the piston (300).
7. Piston-fluid line arrangement according to one of Claims 1 to 6, characterized in that the fluid path (310) has a fluidic connection (330) of an interior and an exterior of the piston (300), wherein
   the fluidic connection (330) is in particular a bore (332), preferably a passage bore (332), and/or an intersection (334), preferably of an internal (322) and external recess (320).
8. Piston-fluid line arrangement according to one of Claims 1 to 7, characterized in that the fluid path (310):

   • has the opening (312) on the outside of the piston (300);

   • comprises a circumferential groove (324) and/or a circumferential facet (324) on the outside of the piston (300) ;

   • has a longitudinal groove (326) and/or a longitudinal facet (326) on the outside of the piston (300);

   • comprises at least one bore (332) from an outer side of the piston (300) to a piston interior (340);

   • has an intersection (334) of an external recess (320) with an internal recess (322); and/or

   • comprises a cutaway portion (328) on a longitudinal end section of the piston (300).
9. Piston-fluid line arrangement according to one of Claims 5 to 8, characterized in that the fluid path (310) is set up analogously to the piston (300) in the fluid line (400).
10. Piston-fluid line arrangement according to one of Claims 1 to 9, characterized in that:

    • the piston (300) is in the form of a control piston (300), a pin, a control pin or a leakage pin (214);

    • a base of the recess (320, 322) is planar or curved;

    • the geometry of the piston (300) is a secondary geometry of the piston (300);

    • a primary geometry of the piston (300) is a cylindrical shape;

    • the geometry of the fluid line (400) is a secondary geometry of the fluid line (400);

    • a primary geometry of the fluid line (400) is a cylindrical shape; and/or

    • the piston (300) is in the form of a hydraulic coupling element.
11. Injector, in particular fuel injector (1) for a direct injection system of an internal combustion engine, characterized in that
    the injector (1) has a piston-fluid line arrangement (300/400), in particular a control piston-control bore arrangement (300/400), according to one of the preceding claims.

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