WO2008145330A1 - High-pressure injector for internal combustion engines having a control-rod support which increases the buckling load via highly pressurized fuel - Google Patents

Abstract

On the housing side, a high-pressure injector (1) has a central receptacle chamber (16) which lies between the actuator and the control valve (17) and is penetrated centrally by a control rod (23) which is multiple times as long as it is thick, and which receptacle chamber (16) forms, at least over part of its length, a pressure accumulator (24), in which the control rod (23) is surrounded directly by the fuel.

Description

 Köchdruek injection injecor engine with a kinkload-increasing control rod support over high-pressure fuel.

The invention relates to a high-pressure injection injector for internal combustion engines according to the preamble of claim 1.

Injection injectors of the aforementioned type are known from EP 1 208 297 B1. Axially opposite to the injection-side end containing the nozzle needle over-steered injection ports containing the injector is provided with an actuator, and lying in the longitudinal central region therebetween with a control valve which has a connection to the high pressure side and the low pressure side and on when connected to the high-pressure side is pressurized with a control chamber located at the back to the nozzle needle, and the nozzle needle is loaded in the direction of its closed position. If the control chamber connected to the low pressure side, the nozzle needle is raised due to the pressurization of lying in the region of its injection-side end pressure shoulder in its open position. In the connection between the control valve and the actuator is an elongated control rod whose length corresponds to a multiple of its thickness and which in turn is guided in a running between the actuator and the control valve socket, which forms an inserted into the valve housing assembly together with the control rod. The variety of the required fits, the machining tolerances and other factors also montage and Temperature-induced tensions are - despite the long and thin, in consideration of the compressive forces as slim as possible control rod and their consequent adaptability - adversely noticeable, in particular, the introduction of the restoring forces on the .Aktor is critical. Therefore, the control rod is provided in the transition to the actuator with a separate and separately guided headboard. Due to the composition of the control rod from the head part and the rod part at transverse to the direction of support surfaces on the headboard and rod part angle and Desachsierungsfehler can be largely compensated. However, the inclusion of the control rod in a separate mounting sleeve also requires space, which is in a certain contradiction to the requirement given for internal combustion engines as slim as possible and space-saving injection injectors.

In an injection injector of similar design according to EP 1 347 168 B1 with a likewise very long and thin knitting needle-like control rod, the tension caused by manufacturing tolerances and assembly and temperature-related stresses is reduced by the fact that the control rod receives the leader and in turn in a bore of the Injector housing recorded mounting sleeve is supported axially to the housing via a support sleeve which is compressed in the clamped state and in which the plastic and the elastic deformation region to compensate for tension is available. Regardless of the achievable thereby reducing the material loads results in view of the high pressures to be controlled at high-pressure injectors and the pressure fluctuations occurring due to work with even higher peak pressures a massive structure of the injector with the corresponding space requirement. DE 101 47 830 A1 also shows a fuel injector with an elongated control rod extending between the actuator and the control valve and guided in a mounting sleeve. The mounting sleeve interspersed, each end sealingly, a lying in the area between the actuator and control valve cavity which forms a fuel injector integrated in the fuel pressure accumulator and is located in the fuel inlet from the side of the housing fuel supply to the controlled via the nozzle needle injection ports.

The integration of a pressure accumulator in the injector is also known from EP 0 333 096 A2. The pressure accumulator is disposed between the nozzle opening on the injection ports and the control valve with downstream actuator and passing through a connecting the control valve with the nozzle needle control rod which is guided on the part of the control valve via a closure plate floating in an intermediate piece of the housing, in the back to Control rod of the control room is provided. The relatively massive and the high-pressure accumulator guide-free passing through control rod is loaded via an enclosing and supported against the cover plate spring in the direction of the closed position of the nozzle needle.

A similar to the basic structure high-pressure injection injector also shows the EP 0 228 578 Bl.

Furthermore, from EP 1 118 765 A2 an injection injector is known, which has a pen-like slim housing part below the fuel supply to the injector, in which the nozzle needle with a shaft portion, whose length is a multiple of its diameter, runs in a central bore over the also the fuel supply to the injection openings takes place, the nozzle needle leaking on the Injection openings in the nozzle body is guided and at the rear over its shaft part expires against a control piston, which forms a boundary of the control chamber. The nozzle needle, which is very long in this solution, can be subdivided into a plurality of elements which are connected to one another, and the control valve is actuated via an actuator which adjoins the nozzle needle almost immediately, so that actuator and control valve as well as the supply connections of the injector are combined in a head part. are short, which builds in comparison to the pen-like nozzle needle-side part of the injector. Due to the elongated, tapered relative to the head part construction of the nozzle needle side part of the injector, the unguided course of the shaft of the nozzle needle in the central bore of the housing and extending over the central bore fuel supply to the Einspritzδffnungen results in a low-production and low-leakage design with a more favorable for installation in internal combustion engines, slender figure. However, this is less suitable for use as a high-pressure injector, in which high, the system pressure far exceeding pressure peaks.

A similar structure of an injection injector is also shown in EP 0 450 532 A1.

From EP 0 686 763 Bl a further injection injector is known, in which the nozzle needle is in alignment with the actuator, to which the control valve is arranged adjacent, the control chamber is limited by a piston part of a multi-part, back against the nozzle needle supported rod connection in a central bore of the housing extends. The fuel supply to the nozzle needle takes place via an off-center longitudinal bore, on which in the intermediate region between sennadel and control valve opens the side fuel supply.

It is known from DE 197 46 143 A1 to provide a hydraulic coupling device operating in the manner of a pressure booster in order to compensate for changes in length in a pressure-resistant connection lying in the connection of an actuator of an injection injector to a control valve. The coupling device comprises a liquid-filled, housing-enclosed coupling space with opposite, housing-guided actuators, between which extends a liquid column. About this liquid column as a pressure column, the actuators are supported against each other under pressure. Occurring leaks are compensated for tensile load of the actuators by a valve-controlled connection of the coupling chamber to the low pressure side.

From JP 11200977 AA, Patent Abstracts of Japan, a fuel injection valve with between the actuator and the Spritzδffnung associated Schließkδrper lying transfer punch is known, which is guided in Düsenkδrper and acts on the Schließkδrper. The transfer punch is split longitudinally and its in-flight stamp parts axially delimit a gap space enclosed by the nozzle body. This gap is in communication with the high pressure side, on the injection port expiring fuel supply via a throttle channel. As a result of this, a fuel cushion that is variable in volume as a function of the application of the transfer punch builds up in the gap, which serves as a stop damper when the valve is opened and closed.

Furthermore, an injection injector is known from US Pat. No. 3,777,977 A, in which the end of the injector axis is opposed to one another. lying on the injection nozzle with extending in the direction of the injector axis nozzle needle and the return-side supply connection are provided. In between, the control valve is located with the valve axis extending transversely to the injector axis and the actuating rod extending in the direction of the valve axis of the actuator designed as a magnetic actuator. The adjusting rod passes through the winding region of the magnetic actuator in a guide and is connected opposite to the control valve with the armature plate of the magnetic actuator. On the armature plate receiving armature space opens the high-pressure side supply port, from which via the armature space and the guide for the control rod, the fuel is supplied to a traversed by the control rod distributor space from which the high-pressure side connections to the nozzle chamber and the high pressure side acted upon control surface of the control valve piston.

The invention has for its object to form a high-pressure injector of the type mentioned in that results in an increased buckling stability of its control rod and that the injector with a simple structure both in terms of manufacturing and assembly tolerances as well as by clamping forces, pressurization and temperature fluctuations caused dimensional changes is insensitive.

This is achieved with the features of claim 1, therefore, by the division of the control rod and lying in the support of the control rod fluid column as a pressure column automatic compensation of changes in length can be achieved because the fluid column as a hydraulic transmission member through the throttled connection to the receiving space, and thus to the high pressure side, represents an adapting to the respective support length volume. Not only are length changes ments of the control rod is compensated relative to those of the injector housing, but in particular the assembly is simplified, since the necessary fine adjustment takes place via the hydraulic transmission path between the control rod parts.

Due to the division of the control rod in rod parts, which form within an enclosing coupling piece - so for example a socket - the axially opposite boundaries of a gap space and of which at least one against the coupling piece is axially displaceable, also results from the throttled connection to the receiving space, and thus to the high pressure side, a rod member axially against each other supporting fuel column, which presses the rod parts according to the applied pressure against their opposing supports, which are formed by the actuator and the control valve. Changes in the distance between the supports are compensated by the throttling connection to the receiving space by nachlaufendes fuel, and in a similar manner also leaks along the rod part or the rod parts, which leak to the gap.

In addition, by integrating a fuel high-pressure accumulator into the injector, the load on the injector is reduced by pressure peaks which extend far beyond the already high system pressures, resulting in lower deformations of the injector housing and a structurally easier construction of the injector, in particular of the injector housing becomes.

In addition, due to the immediate arrangement of the control rod in the high-pressure side acted upon, forming the high-pressure accumulator receiving space in conjunction with the knitting needle-like thin, elongated design of the control rod in the vicinity of the nozzle needle, so at a great distance to the actuator, arranged control valve and the receiving space successful fuel supply to the nozzle even with a slim case based on the size of the injection injector large storage volume. This makes it possible to reduce the magnitude of the pressure fluctuations that arise in connection with the injection, wherein peak pressures occurring in particular with completion of the injection can be reduced.

In particular, due to the directly fuel-enclosed extension of the control rod in the receiving space and a kink stabilization of the control rod, so that they can be formed despite their many times their thickness making up with a lying in the range of one millimeter diameter, with a guide-free length, for example, of 100 or more millimeters and a system pressure of 1500 bar and more corresponding axial load.

The invention thus also provides a method for increasing the buckling stiffness of thin rods by enclosing them with fluids under high pressure, in particular liquids.

The pressure in the gap space can be lowered in the context of the invention in its pressure level compared to the high pressure side given pressure level by an additional connection of the gap to the low pressure side, so that sets a mean pressure level in the gap.

The throttling connection between the gap space and the receiving space, and thus to the high pressure side, can be achieved in the context of the Achieve invention by one or more separate throttle bores, or even via a targeted leakage along the guide of the respective rod part expiring on the gap in the coupling piece. Thus, the height of the pressure building up between the work files in the gap space can also be influenced via the respective throttle cross section, be it as a bore cross section or as a leakage gap, and over the length of the respective throttle section. Supplemented by a throttling connection of the gap to the low pressure side, a limitation of the pressure in the gap space can be achieved and it can be avoided that a pressure builds up in the gap, which in the support to the actuator has a force result, through which the actuator from his the spring-loaded closed position of the control valve corresponding construction position in the direction of its the opening position of the control valve corresponding Absteuerlage is pushed, so that over the actuation of the actuator, the control valve could not be opened.

The one or more engaging in the coupling rod parts are expediently resiliently supported on their gap-increasing position against each other or against the coupling piece, so that structurally a predetermined support length is adjustable by simple means and deviations thereof can be compensated by the self-adjusting length of the liquid column.

Notwithstanding the described solution with lying in the longitudinal central region between the actuator and the control valve coupling piece, the coupling piece may also be formed by the upper and / or lower valve stem guide, the lower valve stem guide is suitably adjacent to an intermediate plate which is provided in the transition from the injector to the nozzle body that's on injection ports leaking nozzle needle receives and is clamped via a screw, in particular via a union nut, together with the intermediate intermediate plate against the injector.

The lower valve rod guide limits the receiving space, is supported radially to the receiving space and takes a floating Sitzkδrper the control valve, the seating surface is sealingly acted upon by the control rod.

When lifted from the seat control rod a control chamber is connected to the low pressure side of the seat body. This control chamber is located at the back to the nozzle needle and is delimited against the intermediate plate via a control sleeve which is axially resiliently clamped between the intermediate plate and the nozzle needle, so that the nozzle needle is loaded in the direction of its closed position to the injection openings. The control chamber has a throttled connection to the high-pressure side, so that the nozzle needle is loaded via the pressure built up in the control chamber in the direction of its closed position and is adjustable pressure-dependent in its open position when switched by opening the control valve connection of the control chamber to the low pressure side.

The solution according to the invention expediently provides a structure in which a quantity-limiting valve is integrated in the receiving space. Conveniently, this flow control valve is adjacent to the lower valve stem guide, so provided in the inlet region on the nozzle needle and thus lies between the valve housing associated high-pressure side port and the nozzle portion of the injector. This results in a particularly simple construction, when the flow control valve has a piston element lying in the inflow path to the nozzle part, the throttling overflow cross-section has cuts and which is spring-loaded in the direction of a constructive starting position against the flow direction. In this constructive starting position, the longitudinally displaceably guided in the receiving chamber piston member is preferably against a housing shoulder, with support of the spring opposite to the Kolbenelernent on the lower valve stem guide. During each injection process, the piston element is displaced in the direction of its blocking position, and, if the injection quantity was not too large, then returned to its original position. Only with large injection quantities, but otherwise properly operating injection injector, speaks the flow control valve and it is the piston member displaced in a Sperrläge that prevents another fuel inlet to the nozzle needle enclosing nozzle space. A quantity limiting valve of the embodiment shown thus does not respond if the amount of fuel flowing over it, based on the throttling overflow cross section of the quantity limiting valve, is too small to displace its piston element.

Further details and features of the invention will become apparent from the claims. Furthermore, the invention will be explained below with reference to an embodiment. Show it:

1 is a sectional view of a high-pressure injection injector according to the invention,

2 is an enlarged view of a section II in Fig. 1,

Fig. 3 shows a further embodiment of an injector according to

Fig. 1 in a corresponding sectional view. 4 shows an enlarged detail of the area IV in FIG. 3, wherein the lower part of a quantity-limiting valve shown in FIG. 2 is additionally shown, and FIG

Fig. 5 to 7

Schematic diagrams for designing the throttling connection of the high-pressure and / or low-pressure side to the gap.

The illustrations in the figures relate to an injection injector 1 for internal combustion engines, is supplied via the supplied under high pressure fuel (arrow 2) of the injection nozzle 3, which has a Düsenkδrper 4, in which in a central bore 5, a nozzle needle 6 is guided axially displaceable over the fuel flow to the injection ports 7 is controlled. To the Düsenkδrper 4 includes aaxially, this overlapping, an intermediate plate 8, which lies in the transition to the housing 9 of the injection injector 1 and which is clamped between Düsenkδrper 4 and housing 9 via a screw, here a union nut 10, the nozzle body engages under a shoulder 11 and which is screwed against the expiring against the intermediate plate 8, lower part of the housing 9. To the axially opposite, o- bere end of the housing 9 of the injection injector 1 includes an actuator 12, which is only indicated in outline and, based on the embodiment, is designed as a magnetic plate having an anchor plate 13.

The anchor plate 13 is axially above a designed as a screw plate 14 end plate, which is bolted to the housing 9 and over which a Abschlusspfropfen 15 for a axially extending through the housing 9 receiving space 16 is clamped sealingly against the housing 9. The receiving space 16, which passes through the housing 9 centrally runs down on the intermediate plate 8, adjacent to the receiving space 16, a control valve 17 is provided, via which the pressurization of a control chamber 18 is controlled, - axially between the rear end of Nozzle needle 6 and the intermediate plate 8 is located and which is bounded by a control sleeve 19, which is axially displaceably guided on the rear, here thus upper end portion of the nozzle needle 4. The rear, upper end portion of the nozzle needle 6 is then designed as a shaft portion 21 to the pressure shoulder 20 of the nozzle needle 6, and the control sleeve 19 is supported via a compression spring 22 in the direction of their engagement with the intermediate plate 8. Via the compression spring 22, the nozzle needle 6 is loaded in the direction of its closed position, in which the fuel flow to the Einspritzδffnungen 7 is blocked by the nozzle needle 6 and the nozzle is closed. The intermediate plate 8 and thus also adjacent to this control valve 17, based on the axial extent of the injection injector 1, near its lower end, and thus results in between the control valve 17 and the actuator serving the actuator 12 has a substantially the length of Housing 9 corresponding, and thus large distance, which is bridged to actuate the control valve 17 via a control valve 17 and actuator 12 extending control rod 23.

The control rod 23 is, as can be seen from the illustrations, formed as a knitting needle-like thin rod whose length corresponds to a multiple of its thickness. Based on the embodiment, the diameter of the control rod 23 is on the order of one millimeter, with a length of 150 mm. This size ratio reflects that the control rod 23 is in proportion to its length in the frame. men of the invention is selected to be extremely thin, although the example given range within the scope of the invention can vary within wide limits.

With reference to the exemplary embodiment according to FIG. 1, the receiving space 16 forms at least over part of its length, in particular in its upper longitudinal area, an accumulator 24 which is in communication with the high-pressure side - arrow 2 - but which is not in the flow path between the high-pressure side. pressure port 27 and the control valve 17 to the nozzle needle 6 is located. The flow path between the high pressure supply (arrow 2) and the control valve 17 and the nozzle needle 6 leads in the lower region of the housing 9 via the lower part 25 of the total over the length of the housing 9 extending receiving space 16, wherein in the embodiment in the transition region between the lower Part 25 of the receiving space 16 and its upper, formed by the pressure accumulator 24 part of the high-pressure side port 27 is located, and in its Ausausungsbereich on the receiving space 16, a coupling piece 26th

The coupling piece 26 is designed in Fig. 1 and 2 as lying in the receiving space 16 sleeve, which is guided over the housing 9 or also freely lying to the housing 9 and which has a central through hole 28. In this through hole 28, the opposite end portions of an upper control rod member 29 and a lower control rod member 30 of the control rod 23 and define within the through hole 28 of the coupling piece 26 with their end faces from a gap 31 from the receiving space 16, or in other ways to the high pressure side , having a restricted connection. In the embodiment according to FIGS. 1 and 2, this connection is achieved by the leakage-prone guidance of the ends of the control rod parts 29, 30 in the through-hole. formed passage bore 28, but may also be formed by a separate, not shown throttle bore. In the context of the invention, it is also axially slidable coupling piece 26, one of the control rod members 29, 30 axially fixed to the coupling piece 26, and only the other displaceable relative to your Kopplungsstύck 26, so that over the length of the guide of the slidably guided control rod part and the Degree of leakage and the amount of pressure in the gap 31 can be influenced.

Based on the illustration shown, the coupling piece 26 is fixed to the housing 9 and it is the control rod parts 29, 30 supported in opposite directions by springs 32, 33, so that on the resilient displacement of the control rod parts 29, 30, the control rod parts 29, 30 in an axial distance position to each other, which, due to the connection to the receiving space 16 or otherwise to the high pressure side, ensures the construction of a pressure column. As a result, the control rod 23 as a whole is an axially multi-part element which is formed by the rod parts 29, 30 and the pressure column constructed in the region of the gap space 31. As a result, an automatic adjustment of the adjusting length of the control rod 23 is achieved at the distance between the control valve 17 and the actuator 12 resulting from tolerances, assembly-related and / or by stresses, in particular thermal stresses.

The exemplary embodiment according to FIGS. 1 and 2 furthermore shows the arrangement of a quantity limiting valve 34 integrated in the injection injector 1 in the lower part 25 of the receiving space 16. The quantity limiting valve 34 has a fundamentally known construction with a blocking piston 35 which is longitudinally displaceably guided in the receiving space 16 and the up a flow-releasing upper stop position is supported by a spring 36 which is supported axially to the housing 9, to the intermediate plate 8 or, as shown, to a lower control rod guide 37. The control rod guide 37 is in turn supported against the intermediate plate 8 and guided radially in the receiving space 16. The locking piston 35 is supported in the flow-releasing position of the flow limiting valve 34 via the spring 36 against a housing shoulder 38 and has throttled upper flow paths in the flow direction on the nozzle part 3. If a predetermined injection quantity is exceeded, there is no or no complete return of the locking piston 35 to its initial position and the locking piston 35 is displaced against the force of the spring 36 in the direction of the lower control rod guide 37. The locking piston 35 thus ultimately reaches a locking position to the lower control rod guide 37, wherein in this locking position the locking piston 35 is supported sealingly on the control rod or guide 37.

The support position is given in the embodiment of FIGS. 1 and 2 by oppositely directed pin-like projections 39, 40 on the locking piston 35 and the lower control rod guide 37, wherein the pin-like projections 39 and 40 are central to the continuous control rod 23 centrally and axially against each other , In the blocking position of the flow control valve 34 thus form on the one hand the overlapping projections 39, 40, the control rod 23 delimiting sealing surface, and it is on the other the locking piston 35 provided with its piston shaft in axial and radial coverage to along the lower control rod guide 37, for example, by longitudinal grooves formed Überströmkanälen 41. These Überstrδmkanäle 41 open in the embodiment of an annular channel 42 in the intermediate plate 8, which has a supply bore 43 and another Ring channel 44 with the lying in the shaft portion of the nozzle needle 5 pressure chamber 45 is in communication, in which the pressure shoulder 20 of the nozzle needle 6 is located.

The control valve 17 has in the embodiment in a frontal _. , the Zwischenbatt S open Auönehmung 46 of the control rod guide 37 lying Sitzkδrper 47 which abuts against the intermediate plate 8 with a drain hole 49 overlapping to a connecting channel 48. About the connecting channel 48 in the intermediate plate 8, the drain hole 49 is connected to the control chamber 18. The drainage hole 49 runs opposite to the connection channel 48 in a seat surface for the control rod 23, and with the control rod 23 raised from the seat surface, the drainage hole 49 communicates via connection channels 50 in the intermediate plate 8 with a connection channel 51 to the low pressure side. The drain hole 49 is itself designed as a throttle bore, or it is formed the inlet to the drain hole 49 throttled. The control chamber 18 is connected via a throttled connection 52, as indicated in Fig. 4, with the high pressure side, here the pressure chamber 45, in connection.

If the control valve 17 is closed in the closed position, that is to say the drainage bore 49 via the control rod 23, the nozzle needle 6 is loaded both via the pressure spring 22 and via the pressure prevailing in the control chamber 18 in the direction of its closed position. It can thus take place no injection process. The control rod 23 is clamped between the Sitzkδrper 47 to which it bears sealingly, and the actuator 12, in particular due to the pressure column constructed in the gap 31 through which the rod parts 29 and 30 supported against each other and against their respective abutment positions on the actuator 12th and are applied to the seat body 47. If the actuator 12 is actuated to initiate an injection process, the armature plate 13 is lifted against spring force and the upper rod part 29 can move in the direction of the actuator 12. This results in a pressure drop in the gap 31, and the lower control rod part 30 can be raised above its pressure in the drain hole 49 by the connection to the control chamber 18 in the drain hole 49. This results in cross channels 53 to the seat body 47 and longitudinal channels 54 between the seat body 47 and the lower control rod guide 37, a connection to the connecting channels 50 and on the low pressure side (arrow 56).

If the actuator 12 is deactivated to terminate the respective injection process, the armature plate 13, which is spring-loaded in the direction of its support position to the control rod 23, drops and acts on the control rod 23 in the direction of its closed position to the drainage bore 49, because of the throttling connection between the gap space 31 and the high-pressure side in the gap space in turn a supporting liquid column is constructed.

Fig. 1 can be clearly seen that results from the axially one behind the other arrangement of pressure accumulator 24, flow control valve 34 and optionally intervening coupling piece 26 a very compact and structurally very well controllable arrangement, especially since the control rod 23 due to their slim design and not shrouded free position within the receiving space 16, which serves at least partially as a pure pressure accumulator 24, has a minimal space requirement, so that it is also possible to realize large and effective accumulator chambers. If, as shown in FIGS. 1 and 2, the coupling piece 26 is arranged in the transition between pressure accumulator 24 and quantity-limiting valve 34, then it is expedient for the high-pressure-side connection 27 to open into the receiving space 16 in the region of the coupling piece 26 and this divides, with over the coupling piece 26 associated channel connections 57, 58 in the direction of the accumulator 24 and in the direction of the flow control valve 34th

Such a design favors, regardless of the operating conditions of injection or non-injection, the maintenance of a substantially equal, high pressure level in the pressure accumulator 24 and thus at great guide-free length of the control rod 23 and their training with a minimized cross-section, characterized in that the computational buckling load of a thin , an accumulator 24 penetrating control rod 23 relative to the rod length between the memory axially passing through the sealing guides increases with increasing pressure, thus the control rod can be designed for a buckling load, which corresponds to the arithmetical buckling load plus an additional buckling load, which is a product of the pressure in Pressure accumulator and the cross-sectional area of the control rod in the axial sealing guides to the receiving space 16 results. The invention thus also provides a method, when using pressure-applied thin rods, such as control rods 23 of the type mentioned above, to minimize them in terms of their dimensions, characterized in that the product given from the enclosing to the rod in a pressure accumulator Pressure and the cross-sectional area of the rod in its exit surface to the pressure accumulator as an aggregate size for arithmetic buckling load is taken into account. Thus, a method for increasing the buckling strength of thin rods is shown. Although the embodiment of an injection injector 1 according to FIGS. 1 and 2 represents a particularly advantageous solution according to the invention, the invention can also be implemented in an embodiment according to FIG. 3, in which a quantity limiting valve is not provided here, but can also be provided according to the invention - The coupling piece is formed by one of the control rod guides, in particular, as shown by the lower control rod guide 45. This eliminates the Quasiaufteilung the receiving space 16, which is essentially as a central through hole, as well as a possible guidance of the control rod 17 via the coupling piece 26 in the longitudinal central region between the actuator 12 and the control valve 17. Such a lean solution, the rest of the structure of 1 and 2 corresponds to represents further simplification of the solution according to the invention and it also illustrates that in the arrangement of a coupling piece 26 as shown in FIG. 1 and 2, this may be provided floating in the receiving space 16, with appropriate axial support against the control rod parts 29 and 30.

Furthermore, in FIG. 3, in addition to FIG. 1, a further arrangement possibility for the pressure spring 59 supporting the armature plate 13 is illustrated as part of the actuator 12.

Fig. 4 illustrates that when dividing the control rod 23 in the region of the lower control rod guide 37, the upper control rod member 29 is many times longer than the lower control rod member 30, in position of the gap 31 between these rod parts. According to the arrangement of the gap 31 in the extension region of the lower control rod guide 37 and the use of this control rod guide 37 as a coupling piece with leakage connection to the receiving space 16 Ie- in this solution, the leakage between the gap space 31 and the receiving space 16 and the height of the pressure building up in the gap 31 by fixing different guide lengths and guiding games between the upper rod part 29 can be simply exceeded by the section of the upper control rod part 29 which dips into the control rod guide 37 and lower control rod guide 37 as a coupling piece, taking into account the corresponding radial tolerances in the guidance of the control rod 23 in the lower control rod guide 37.

In addition to Figs. 1 and 2, Fig. 4, based on the extent in FIGS. 1 and 2 corresponding to the lower part of the quantity limiting valve supplemented representation of FIG. 3, the high-pressure side connection 52 of the control chamber 18 via connection channels 60th Furthermore, it can be seen from FIG. 4 that the invention, in particular in the embodiment according to FIG. 4, advantageously permits a construction of the control rod 23 of different materials over its length. For this purpose, the short lower control rod part 30 in the embodiment according to FIG. 4 altogether consist of a high-strength material which is particularly suitable with respect to the seal to the drainage bore 49.

Since otherwise the embodiments largely correspond to the same reference numerals use and reference is made to the description of FIGS. 1 and 2 with respect to the embodiment of FIGS. 3 and 4.

Regardless of the use of thin control rods, due to the kink stabilization provided for the control rod by the pressurization in the receiving space, the transmission may be large, corresponding to the pressure build-up in the gap Stellkräfte be guaranteed. Due to the cross-sectional dimensioning of the control rod parts delimiting the fluid column in the gap, the supporting force exerted on the control rod parts can also be limited. Based on a given pressure level in the gap, a force adjustment to the spring force of the actuator can thus take place via the cross-sectional dimensioning of the control rod parts in the coupling piece, so that the spring can not be overpressed.

5 to 7 show a highly schematic and isolated representation of a structure in which a control rod 70 passes through a coupling piece 71 in an axial bore 72 and in which the control rod 70 has two control rod parts 73 and 74, of which the control rod part 73, based on the above-described embodiment examples, an upper, actuator-side control rod part forms and the control rod member 74 is a lower. The control rod parts 73 and 74 are guided longitudinally displaceably in the axial bore 72 and delimit axially with their mutually adjacent end faces within the axial bore 72 a gap 75 radially enclosed by the coupling piece 71.

The coupling piece 71 is shown as lying within a receiving space 76 which is penetrated by the control rod 70, so that the control rod parts 73, 74, in the embodiments according to FIGS. 5 and 6, proceeding from the gap space 75 in the axial bore 72, on opposite one another Areas of the Aufnähmeräumes 76 expire, based on the representations of FIG. 5 and 6, respectively, as shown by the + sign, are at high pressure level.

The control rod parts 73 and 74 define in the axial bore 72 opposite the coupling piece 71 respectively leakage gaps 77, 78, so that in the gap space 75, from the receiving space 76th supplied via the leakage gaps 77 and 78, the receiving space 76 corresponding pressure builds up, and in the gap 75 is given a pressure column over which, with a corresponding axial load, the control rod parts 73, 74 are supported against each other, so can transmit corresponding axial support forces.

Due to the pressure supply via the leakage gaps 77, 78, the control rod parts 73, 74 are displaced from each other by enlarging the gap space 75 if no corresponding opposing forces are present, or if, for example due to a resilient support, due to the pressure built up in the gap space 75 there are restoring forces that are greater than these opposing forces.

In order to avoid an overpressing of the spring in accordance with yielding support of one of the control rod parts, so for example, the control rod member 77 against the spring of an actuator, either the pressure in the gap 75 must be limited accordingly, or the cross-sectional area of the respective control rod part limiting the gap space in that, based on a predetermined limit pressure, a predetermined limit force corresponding to the spring force is not exceeded.

In the exemplary embodiment according to FIG. 5 with connection of the gap 75 via the leakage gaps 77, 78 only to the receiving space 76, relative to a given pressure in the receiving space 76, a corresponding force limitation can only be achieved via the cross-sectional area of the rod part or parts 73, 74.

In the exemplary embodiment according to FIG. 6, the gap 75 is additionally connected via a throttling connection 79 to a lower connection 79. derdruckraum 80 connected, the pressure level - as a low pressure level - below the given in the receiving space 76 high pressure level (indicated by +), and is characterized by -. The throttling connection 79 is shown schematically as a bore 81 in the control rod portion 74, but can also be realized in other ways, for example, by a gap opening on the gap 75, the coupling piece 71 passing through and opening to the low-pressure chamber 80 bore.

Due to the connection to the low-pressure space 80, in conjunction with the connections given to the high-pressure side receiving space 76 via the leakage gaps 77 and 78 in the gap 75, an average pressure level is formed in connection with corresponding cross-sectional dimensions for the control rod parts 73 , 74 allows the determination of a desired maximum actuating force, based on this average pressure level.

Fig. 7 shows a variant in which the coupling piece 71 aaxially limiting to a receiving space 76 in the transition to a low pressure chamber 80, in such a way that the control rod 70 from the coupling piece 71 at one end to the high-pressure receiving space 76 and the other on the low pressure chamber 80 expires. The control rod parts 73 and 74 thus form a delimitation of the enclosed between their opposite end faces gap 75 on the one hand against high pressure, on the other hand against low pressure, so that on the leakage gaps 77 and 78 in the gap 75 a lying between the high pressure side and the low pressure side pending, mean Pressure setting. On the order of magnitude, this average pressure is determined by the dimensioning of the leakage gaps 77 and 78 as well as their axial length. ge, and thus the size of the rod members 72 and 74 in response to the pressure in the gap 75 acting support forces. As already described above, these can also be influenced by the cross-sectional dimensioning of the rod parts 73, 74 leading to the gap 75.

In principle, the embodiments illustrated with reference to FIGS. 5 and 6 are not bound to the fact that both control rod parts 73, 74 are longitudinally displaceable relative to the coupling piece 71. Rather, with a corresponding longitudinal displaceability of the coupling piece 71, it can also be fixedly connected to one of the control rod parts exiting from the coupling piece 71 on the high pressure side, for example forming the control rod part 74 and forming part of the coupling piece 71, so that a leakage gap 77 to the high pressure side is only longitudinal the rod member 73 is given. Even with such a solution, in analogy to the design according to FIG. 5, the actuating force resulting from a predetermined pressure level in the gap 75 can be influenced by the cross-sectional dimensioning. In the embodiment according to FIG. 6, the additional possibility of influencing the change in the pressure building up in the gap 75 is that, according to FIG. 6, a connection of the gap 75 to the low-pressure space 80 via a throttling bore connection 79 in the manner of the coupling piece 71 positionally fixed control rod part 74 can be made. In such a solution, the connection to the low-pressure chamber 80 can preferably also take place directly via a bore passing through the coupling piece 71.

In the context of the invention, it is also to divide the control rod several times, so that there are several separation points. In such a configuration, the z. Under production tion and / or assembly points of view may be expedient, is formed at the separation point, a correspondingly enclosing coupling piece, a the correct distance adjusting gap from in which forms the largest supporting force. In the other separation points, the rod parts are in abutment with each other, so there is no transmitting, the support length adjusting liquid column between the facing end faces of the rod parts available.

Claims

claims A high-pressure injector (1) for internal combustion engines with an actuator (12) and an injector (3) for high-pressure fuel supplied, which are arranged on axially opposite end sides of the slender injector (9) and with one in the control of the injector (3) located in the transition from the injector (9) to the injection nozzle (3) arranged control valve (17) by the actuator (12) via a knitting needle-like thin, elongated stabfδrmige control rod (23) is driven in the transition from the actuator ( 12) on the control valve (17) in an axially the injector housing (9) passing through the receiving space (16) and the two end face mutually supported control rod parts (29, 30), characterized in that the receiving space (16) is connected on the high pressure side, that the control rod (23) in a high-pressure accumulator-forming receiving space (16) is directly fuel-enclosed that the zugewa each other The end faces of the control rod parts (29, 30) are fluidly supported relative to each other and within an enclosing coupling piece (26) and that at axial Verschieblichkeit at least one of the control rod parts (29, 30) to the coupling piece (26) the control rod parts (29, 30) with their End sides axially define a gap space (31), which stands in throttled connection at least to the high pressure side. 2. High-pressure injection injector according to claim 1, characterized in that the gap space (31) is in throttled connection to the low pressure side. 3. High-pressure injection injector according to claim 1 or 2, characterized in that the two control rod parts (29, 30) in the coupling piece (26) are axially displaceable. 4. High-pressure injection injector according to one of claims 1 to 3, characterized in that the coupling piece (26) in the receiving space (16). 5. High-pressure injection injector according to one of claims 1 to 3, characterized in that the coupling piece (26) forms an axial boundary of the receiving space (16). 6. High-pressure injection injector according to one of the preceding claims, characterized in that at least one of the throttled connections of the gap space (31) to the high pressure side or the low pressure side by a leakage gap between the control rod (23) and the coupling piece (26) is formed. 7. High-pressure injection injector according to one of claims 1 to 6, characterized that zvon the throttled connections of the gap space (31) to the high pressure side or the low pressure side is at least one formed by a throttle bore. 8. High-pressure injection injector according to claim 6 or 7, characterized in that. that the throttled connection of the gap space (31) to the high-pressure side emanates from the receiving space (16). 9. High-pressure injection injector according to one of the preceding claims, characterized in that the coupling piece (26) to the receiving space (16) is axially fixed in position. 10. High-pressure injection injector according to one of claims 1 to 8, characterized in that the coupling piece (26) to the receiving space (16) is axially displaceable. 11. High-pressure injection injector according to one of the preceding claims, characterized in that the coupling piece (16) forms a radial guide for the control rod (23). 12. High-pressure injector according to one of claims 1 to 4, characterized in that the receiving space (16) by the coupling piece (26) axially in an adjacent to the actuator (12) upper part is divided as a storage part and a lower part and in Area of the lower, between the coupling piece (26) and the Control valve (17) lying part forms a fuel channel. 13. High-pressure injection injector according to claim 12, characterized in that the high-pressure side connection to the receiving space (16) in the region of the coupling piece (26). 14. High-pressure injection injector according to one of the preceding claims, characterized in that in the receiving space (16) a flow limiting valve (34) is arranged. 15. High-pressure injection injector according to one of claims 12 to 14, characterized in that the quantity limiting valve (34) in the lower part of the Receiving space (16) is arranged. 16. High-pressure injection injector according to claim 14 or 15, characterized in that the quantity limiting valve (34) has a spring-supported, a throttling flow cross section to the injection nozzle (3) limiting the blocking piston (35). 17. High-pressure injection injector, in particular according to one or more of the preceding claims, characterized in that the control rod (23) is supported kinkstabilisierend in the high pressure side connected receiving space (16) via the enclosing fuel under high pressure. 18. High-pressure injection injector according to claim 17, characterized in that the control rod (23) is supported kinklaststeigernd on the circumferentially enclosing, standing under high pressure fuel.