WO2017097412A1

WO2017097412A1 - Fuel injector arrangement

Info

Publication number: WO2017097412A1
Application number: PCT/EP2016/002056
Authority: WO
Inventors: Markus Kalenborn
Original assignee: L'orange Gmbh
Priority date: 2015-12-11
Filing date: 2016-12-07
Publication date: 2017-06-15
Also published as: DE102015016034B3

Abstract

The invention relates to a fuel injector arrangement (1) having a fuel injector (3) for operation with fuel gas, wherein the fuel injector (1) has a fuel gas nozzle valve element (13) having a piston part (29) and a valve element part (31), wherein the piston (29) is accommodated in a housing (39) and therein divides off a first (47) and a second (49) hydraulic control chamber that is variable in volume, wherein the fuel injector (3) is set up to divert gap leakage from a piston guide gap (57) around the piston part (29) into a blocking fluid sealing chamber (59) formed around the valve element part (31) and belonging to a blocking fluid sealing system (61) of the fuel injector (3), in order to form a blocking fluid seal (63) on the valve element part (31).

Description

DESCRIPTION Fuel injector assembly

The present invention relates to a Kraftstoffmjektoranordnung according to claim 1.

In the prior art, it is known that in fuel injectors, which are provided for the discharge of fuel gas and which use hydraulic fluid for the control of the fuel gas injector, in particular liquid fuel, the problem is that fuel gas inadvertently enters the hydraulic control circuit, in particular Creep paths along respective Brermgas needle guides or valve member guides owed. Proceeding from this, the object of the present invention is to provide a fuel injector arrangement which effectively and structurally avoids a fuel gas entry into the hydraulic fluid.

This object is achieved with a fuel injector arrangement having the features of claim 1.

Advantageous developments and embodiments of the invention are specified in the further claims. According to the invention, a fuel injector arrangement with a fuel injector for operation with fuel gas, for example in the form of natural gas, special gas, landfill gas, biogas, hydrogen or the like, is proposed. The fuel injector may be a single-fuel injector, which in particular has a hydraulic control circuit for controlling a fuel gas nozzle valve member, alternatively and preferably a dual-fuel fuel injector, which can also emit liquid fuel in addition to fuel gas, for example diesel fuel, heavy oil or bio-oil.

Here, the liquid fuel is preferably also used to provide or formation of the hydraulic control circuit for the fuel gas nozzle valve member. Such a fuel injector can be provided, for example, for an ignition jet operation in which the fuel gas is ignited by means of a small quantity of liquid fuel injection (ignition jet). The A fuel injector assembly having a fuel injector as discussed above is preferably part of a common rail fuel injector.

Generally, the fuel injector assembly may be e.g. be used with a large engine, for example in a motor vehicle such as a ship or a commercial vehicle, or be provided, for example, for a stationary device, e.g. for a combined heat and power plant, an (emergency) generator, e.g. also for industrial applications.

The fuel injector of the fuel injector arrangement according to the invention has a fuel gas nozzle valve member which comprises or consists of a piston part and a valve member part. The fuel gas nozzle valve member, in particular, the valve member part, preferably cooperates with a nozzle valve seat to form a fuel gas nozzle valve of the fuel injector to selectively open and close a fuel gas flow path toward a fuel gas nozzle assembly of the fuel injector depending on a stroke position of the fuel gas nozzle valve member to be able to. The piston member is further intended to effect a lift control of the fuel gas nozzle valve member in the context of a hydraulic piston control device, i. for an injection operation. As a hydraulic fluid for the piston control is preferably a liquid fuel such as diesel fuel. Preferably, the valve member part is formed in the form of a nozzle needle, in particular rod or rod-shaped, wherein the piston part is further provided in particular with a larger cross-section than the valve member part, in particular on the valve member part (remote from the nozzle end), e.g. molded or formed integrally therewith, for example as a (cylindrical) thickening.

The piston member is housed in a (control) housing of the fuel injector (which housing is provided by, for example, at least one injector housing member, for example, a nozzle body and a cover member thereof) and divides a first and a second hydraulic control chambers therein in a volume variable manner. In the context of the piston control device thus formed from the first and second hydraulic control chamber and piston part or the hydraulic control circuit formed therewith, a stroke control of the fuel gas nozzle valve member is made possible by selective hydraulic relief and load the control chambers, with a load of high pressure hydraulic fluid with

Pressure levels of eg 380bar to 550bar is provided. In this case, generally preferred is an axially aligned arrangement in which the fuel gas nozzle valve member is axially displaceable stroke, thus also the piston part in the housing. The first hydraulic control chamber can in this case be closer to the nozzle, the second hydraulic control chamber can be formed further away from the nozzle in the likewise axially oriented housing.

According to the invention, the fuel injector is arranged to divert gap leakage from a piston guide gap (in particular annular gap) around the piston part, ie formed between piston part and housing (wall), into a barrier fluid sealing chamber (in particular ring chamber) formed around the valve member part of a barrier fluid seal system of the injector Make barrier fluid seal on the valve member part.

With this configuration, it is thus advantageously easy to form a (barrier) fluid seal on the valve member part by means of the hydraulic fluid (gap leakage), which is able to prevent an overflow of fuel gas into the hydraulic control circuit along a guide of the valve member part, i. by means of (blocking) fluid on the guide locks. This can be the

Invention continue to make advantageous advantage of the fact that over the piston gap between the piston part and the housing, a pressure reduction in the sense of Vordrosselung is achieved, so that on the design of the piston guide gap or on the choice of a tap position, a pressure level of the redirected gap leakage for the formation of the sealing fluid seal advantageously preset is.

In the proposed embodiment of the fuel injector - in addition to the Sperrfluiddichtkammer - preferably the entire Sperrfluiddichtungssystem exclusively via the gap leakage from the piston gap, which is redirected to the barrier fluid seal, supplied with hydraulic sealing fluid or barrier fluid (gap leakage), so that an additional barrier fluid supply port can advantageously account for the fuel injector.

In particular, in order always to be able to redirect the gap leakage sufficiently reliably to the barrier fluid seal, it is proposed in a preferred embodiment of the fuel injector arrangement that the fuel injector has a collecting groove around the piston part for the diversion of the gap leakage. Such a collecting groove is preferably an annular groove, wherein in the collecting groove, for example, from the housing wall abgestriffene Spaltleckage can be introduced. In order to continue to spend the gap leakage from the collecting groove to the Sperrfluiddichtkammer, can the fuel injector in this case have a line branch for the diversion of the gap leakage, for example a specially formed drilling channel, which can be flowed over by the collecting groove and is guided to the barrier fluid sealing chamber. Advantageous embodiments of the fuel injector are in this case, for example, that the fuel gas nozzle valve member for forming the line branch has a (axially extending) hollow bore, in particular a blind bore. Such a hollow bore may extend through the piston part and a longitudinally-central portion of the valve member part and be flowed, for example via at least one radial tap hole from the collecting groove. For example, a further radial tap hole, starting from the hollow bore - formed at the other end of the hollow bore - then the Sperrfluiddichtkammer can be supplied with supplied from the hollow bore barrier fluid (gap leakage) or supplied. An open (drilling tool) inlet end of the hollow bore, which is preferably formed remote from the nozzle on the piston part, can in this case be closed with a closure element or a stopper.

In general, it is thus provided that the line branch - as a component of the barrier fluid sealing system, as in bringing also the collecting groove - connects the collecting groove communicating with the barrier fluid seal chamber. An alternative embodiment of the fuel injector arrangement may additionally provide, for example, that the fuel injector for the diversion of the gap leakage has a collecting groove, which is formed in the housing peripheral wall around the piston part. Here, the collecting groove may be e.g. Strip the gap leakage from the piston part, i. for supply to the barrier fluid seal chamber. However, such a configuration requires an internal processing of the housing peripheral wall and could be more expensive to manufacture in this regard. A conduit which communicatively connects the collection groove and the barrier fluid seal chamber could be incorporated into an injector housing member, e.g. adjacent to the

Housing extending - be formed, for example, in turn with a longitudinal bore and first and second stub or transverse bore.

Advantageously, it is also provided in the context of the invention to design the piston part with a first and a second cross section or stepped. Such a solution is considered, in particular, with preferred embodiments, in which the collecting groove is supplied with hydraulic fluid essentially only via the nozzle-remote control chamber. This one is still here preferably a pressurizable with closing pressure control chamber, that is a control chamber, which is pressurized or loaded over the vast period of operation - to comply with the closed position of the fuel gas nozzle valve member. A portion of the piston part with a smaller cross section - forming a relatively further piston gap portion - extends from the nozzle remote control chamber to the collecting groove, a section with a larger cross-section - forming a relatively narrow piston gap portion - from the collecting groove in the direction of the nozzle closer control chamber.

Alternatively or additionally, it can be provided that the piston part has a sealing ring, which sealing ring between the collecting groove and the valve member part side piston part end against the housing or peripheral wall around the piston is sealingly arranged on the same. With the above measures, on the one hand, an advantageously good seal between the control chambers can take place, on the other hand a reliable supply of hydraulic fluid to the barrier fluid sealing chamber can be ensured (insofar as the relatively further piston gap section is substantially constantly filled with pressurized hydraulic fluid during injector operation).

Generally and preferably, it is also provided in a development of the invention that the

Locking fluid system is connected communicating to a leakage system of the fuel injector, in particular downstream. Here, the barrier fluid sealing chamber is provided as a throughput volume. Such a configuration may provide, for example, that barrier fluid from the barrier fluid seal chamber can be diverted via a line connection to the leakage system, which e.g. a throttle device, e.g. continue a check valve. Still further preferred is that the barrier fluid system is connected via a pressure regulating device of the same communicating to the leakage system of the fuel injector.

By means of such a pressure regulating device, for example a pressure regulating valve, the pressure in the barrier fluid system can be adjusted, for example, as a function of a currently prevailing fuel gas pressure, for example if this is different in the partial / full load operation of the fuel injector, or regulated for example to a constant pressure. Preferably, a barrier fluid pressure is set in the barrier fluid sealing system, which is about 10 to 30 bar above the fuel gas pressure level (which, for example, is 350 bar). Any overflow of barrier fluid into the fuel gas portion of the fuel injector This can be regarded as irrelevant via a valve member part guide in a fuel gas nozzle chamber, since this is simply consumed in the fuel gas operation.

In the proposed fuel injector arrangement, the barrier fluid sealing system may also have at least one further barrier fluid seal, which is supplied with barrier fluid via the barrier fluid seal system or conduit paths thereof. For example, a drain line from the barrier fluid seal chamber may be around the valve member portion passing over the

Pressure regulating device leads to the leakage system of the fuel injector branches, in particular upstream of the pressure regulating device, which can be supplied with barrier fluid via the branch, the further barrier fluid seal. An outflow line from the second barrier fluid seal can in this case, in particular upstream of the pressure regulating device and downstream of the branch, re-open into the outflow line from the barrier fluid seal around the valve member part. A further barrier fluid seal can be formed, for example, on a gap guide on the fuel injector in which an element is displaceably guided, in particular between a fuel gas side and a hydraulic side. For example, such a gap guide may be formed on a hold-down member, such as a stilt, which applies a closing force to the fuel gas nozzle valve member, in particular to the piston member and, for example, to a fuel gas passage and / or storage space, e.g. provided as a fuel gas buffer.

In the context of the present invention, a fuel injection system is furthermore proposed which has at least one fuel injector arrangement as discussed above. In this case, the fuel injection system is preferably set up to set a pressure level in the barrier fluid sealing system by means of the pressure regulating device, which is above a fuel gas supply pressure in the range from 10 bar to 30 bar.

Furthermore, an internal combustion engine is also proposed which has a fuel injector arrangement as discussed above or a fuel injection system as discussed above.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figure of the drawings, the invention shows essential details, and from the claims. The individual features may be implemented individually for themselves or for a plurality of different combinations in a variant of the invention. Preferred embodiments of the invention are explained below with reference to the accompanying drawings. Show it:

1 shows an example and schematically a fuel injector according to a

possible embodiment of the invention in a broken sectional view.

In the following description and the drawings, the same reference numerals correspond to elements of the same or comparable function.

1 shows an example and schematically a fuel injector 1 with a fuel injector 3 for operation with fuel gas, the fuel injector 3 may be configured as a single-fuel or as a dual-fuel fuel injector, i. when configured as a dual-fuel fuel injector for a liquid fuel operation, e.g. as part of an ignition jet process or for pure liquid fuel operation. The fuel injector 3 has an injector 5, which by means of a number of

Housing elements is formed, for example by means of a nozzle body 7, further comprising a nozzle body 7 lidding element 9 as an intermediate plate or another

Housing member 11. In the nozzle body 7, a fuel gas nozzle valve member 13 of the fuel injector 3 is received, which acts against a valve seat 15, i. forms together with this a fuel gas nozzle valve 17 of the fuel injector 3. Depending on the stroke position of the fuel gas nozzle valve member 13, pressurized fuel gas from a fuel gas nozzle chamber 19 can be selectively released therefrom, i. via a downstream fuel gas nozzle assembly 21 of the fuel injector 3. For supplying fuel gas to the fuel gas nozzle chamber 19, for

Example with a pressure level of about 350 bar, the fuel injector 1 has a supply line 23 which is guided from a fuel gas inlet 25 of the fuel injector 3 to the fuel gas nozzle chamber 19. This can continue in the supply line 23 a fuel gas storage 27 may be formed, for example, provided by a partially enlarged volume in the supply line 23rd

The fuel gas nozzle valve member 13 now has a piston member 29 and a - adjoining - valve member part 31 which are fixedly connected to each other, in particular integrally formed. As shown in FIG. 1, the valve member portion 31 is formed like a nozzle needle, further having a longitudinal central portion 33. At the longitudinal central portion 33 of the valve member member 31 by means of a same circumferential guide 35, formed by means of a fuel gas nozzle valve member 13 receiving Axial bore 37 (in the nozzle body 7) tight fitting or performed with very little radial play, ie with a radial play AI. Via the guided section or the longitudinally central region 33, the valve member part 31 in this case has a diameter Dl.

The piston part 29 or the piston is formed at a nozzle-distal end of the fuel gas nozzle valve member 13, adjacent to the valve member part 31, that is with a diameter which is greater than Dl, generally by means of a cross-sectional widening of the rod-shaped part forming the valve member part 31 Portion of the fuel gas nozzle valve member 13.

The piston part 29 is accommodated in a (control) housing 39, which is formed by means of a bore in the nozzle body 7, starting from which the guide 35 of the

Valve member portion 31 wegerstreckt toward the fuel gas nozzle chamber 19. The housing 39 is further capped by the nozzle body 7 lidding element 9, as well as a spring-loaded hold-down element 41 in the form of a stilt element, which is pressed against the nozzle-distal end of the piston member 29 in abutment, ie. to provide for a reliable receipt of the closed position of the fuel gas nozzle valve member 13. At this point, it should be noted that the biasing means 43 of the hold-down element (pressure spring) is advantageously accommodated in the intermediate storage space 27 of the fuel gas supply line 23, thus no additional space is required at the fuel injector 3 for the biasing device 43. It should also be noted here that the axially displaceable stilt element 41 is guided in a (radially) play-related guide 45 in the lidding element 9.

The piston part 29 accommodated in the housing 39 divides a first 47 and a second 49 hydraulic control chamber in a volume-variable manner. The first hydraulic control chamber 47, which is formed closer to the nozzle, is provided to have an opening pressure upon loading thereof exerting the piston member 29, the second control chamber 49, which is formed nozzle-distant, to exert a closing pressure on the piston member 29 when loaded.

The piston control device formed by first 47 and second 49 hydraulic control chamber and the piston member 29 further comprises a control valve 51 (pilot valve) via which both a hydraulic fluid load path (supply path from the high pressure side) 53 of the fuel injector 3 and a hydraulic fluid discharge path 55 (FIG. Outflow path to the low pressure side) of the fuel injector 3 is guided. The control valve 51 is preferably provided as a 4/2-way valve, for example as a slide valve or e.g. as a combination of two 3/2-way valves. Depending on the switching position of the control valve 51, a hydraulic pressure can either act on one hydraulic control chamber 47 or 49 (load), while the other hydraulic control chamber 49 or 47 is relieved towards the low-pressure side (outflowing hydraulic fluid) or vice versa.

In the switching position shown, for example, the second hydraulic control chamber 49 is loaded, while the first hydraulic control chamber 47 is relieved, that is, the fuel gas nozzle valve member 13 is urged into the closed position shown. If the control valve 1 is reversed, the second hydraulic control chamber 49 can be relieved and the first hydraulic control chamber 47 loaded, so that a lifting of the fuel gas nozzle valve member 13, in particular in

Connection with a combustion chamber pressure, against the closing force of the hold-down element 41 is made possible, that is, the fuel gas nozzle valve member 13 is urged in the open position. As can be seen, the stroke of the fuel gas nozzle valve member 13 is controlled hydraulically with the thus configured piston control device.

In this case, the fuel injector 3 is also equipped - in the invention characterizing manner - to redirect gap leakage from a piston guide gap 57 around the piston member 29 into a sealing fluid sealing chamber 59 of a barrier fluid sealing system 61 of the fuel injector 3 formed around the valve member member 31, to a sealing fluid seal 63 on the valve member member 31 form.

The barrier fluid seal 63 in this case surrounds the valve member part 31 at the tightly guided portion 33 and within the same, wherein the barrier fluid seal chamber 59 by means of an annular groove - within the axial extent of the guide 35 - is formed in the nozzle body 7, which is open against the adjacent valve member part 31. Such is by means of registered in the sealing fluid sealing chamber 59 and pressurized hydraulic fluid or

Blocking fluid in the form of redirected gap leakage effectively prevents overflow of fuel gas from the fuel gas nozzle chamber 19 via the axial bore 37 into the housing 39 and thus the hydraulic control circuit.

Preferably, for the reliable diversion of the gap leakage is provided to form the piston member 29 with stepped cross-section, wherein a first portion 29a with a relatively smaller cross section or diameter D2 from the nozzle distal end of the piston member 29 and the second hydraulic control chamber 49 to to a collecting groove 65 which is formed around the piston member 29 as an annular groove.

A second section 29b with a relatively larger cross-section or a diameter D3 further extends from the collecting groove 65 to the nozzle-near end of the piston member 29 and toward the first hydraulic control chamber 47. Thus, a piston guide gap 57 is formed around the piston member 29, which has over the first portion 29a relatively wide clearance A2 to the piston peripheral wall and which has over the second portion 29b relatively narrow clearance A3 to the piston peripheral wall. In general, a fuel injector design is therefore aimed at as follows: D3> D2> D1 and furthermore A1 <A3 <A2.

For even better sealing between the first 47 and the second 49 hydraulic control chamber, which can keep the leakage losses during the opening even further low, thus allowing a faster opening, may be arranged around the piston member 29, a sealing ring 67 or piston ring, that is between the collecting groove 65 and the nozzle near the piston part end.

With this configuration, the collecting groove 65 receives predominantly or almost exclusively gap leakage from the piston guide gap 57, which is present there over the first portion 29a, ie when the fuel injector 3 is regularly pressurized. This is because the gap leakage conducted by the second or closing-pressure hydraulic control chamber 49 via the piston gap 57 to the collecting groove 65 is or is subject to hydraulic pressure over the majority of the operating time portions. In order to redirect the gap leakage to the barrier fluid seal chamber 59, the Sperrfluid- sealing system 61 further comprises a line branch 69, which valve member 13 is formed by means of a hollow bore formed as a blind bore 71 in the fuel gas nozzle. The

Hollow bore 71 extends over a portion of the nozzle distal end of the

Piston part 29 into the guided portion 33 into (axially), on which the barrier fluid seal 63 is formed. Düsenfern the hollow bore 71 is in this case closed with a plug member 73.

The hollow bore 71 formed in this way can be acted upon or flowed against by the collecting groove 65 via at least one radially executed tap hole 75, whereby the barrier fluid seal chamber 59 exits through at least one further radially executed tap hole 77 over the entire possible fuel gas nozzle valve member - Position range - with the thus redirected gap leakage fluid can be flowed. Noteworthy is in the context of the arrangement shown here that on the choice of the width of the piston guide gap at the first portion 29a a pre-throttling, thus a pressure level, is selectively preset, under which or with which the gap leakage can be tapped off via the collecting groove 65. About the bypass branch 69, the branched fluid can then be supplied to the barrier fluid seal chamber 59 without further significant throttling or pressure influencing.

As also illustrated in FIG. 1, the fuel injector assembly 1 continues to be

Leakage system 79, to which the Sperrfluiddichtungssystem 61 of the fuel injector 3 - downstream - communicatively connected, in particular via a Druckreguliervor- direction 81. Here, a discharge line 83 of the Sperrfluiddichtungssystems 61 from the Sperrfluiddichtkammer 59 leads to the pressure regulating device 81, which in this case a pressure in the sealing fluid sealing system 61 is adjustable. The pressure regulating device 81 is preferably formed by means of a variable pressure regulating valve, which allows an adjustment of the pressure level of the barrier fluid seal 63 or in the barrier fluid sealing system 61 to a straight prevailing fuel gas supply pressure level, that is by appropriately varied Absteuerfluid of the downstream leakage system 79 (towards

Low pressure side). In the illustrated embodiment of the fuel injector 3, the barrier fluid sealing system 61, connected in parallel to the discharge line 83, further comprises a blocking fluid circuit 85, via which a further barrier fluid seal 87 is supplied with barrier fluid from the gap leakage of the piston guide gap 57.

The further barrier fluid seal 87 is in this case-by means of a further barrier fluid seal chamber 89-formed around the portion of the hold-down element 41 accommodated in the guide 45 and effects a seal against fuel gas leakage, which would otherwise run along the gap guide around the stilt member 41 into the (control) ) Housing 39 could enter, that is, from the fuel gas side formed by the buffer 27 to the hydraulic side (of the hydraulic control circuit or the piston control device). In order to form the barrier fluid circuit 85 with the further or second barrier fluid seal 87, a first line branch 91 of the barrier fluid circuit 85 branches off from the outflow line 83 (and upstream of the pressure regulator 81) to the further barrier fluid seal chamber 89, where it causes the pressure build-up in the sealing functionality the further barrier fluid seal chamber 89 by means of the barrier fluid (gap leakage hydraulic fluid). On the outflow side from the further barrier fluid seal chamber 89, a second line branch 93 leads, which branches back into the outflow line 83 downstream of the branch point 95 of the first branch line 91 (and upstream of the pressure regulating device 81).

With this arrangement, it is thus possible, via the pressure regulating device 81, to set the pressure in the entire barrier fluid sealing system 61, that is, in both barrier fluid seal chambers 59, 89 and the respective barrier fluid seals 63, 87. The fuel injector arrangement 1 or a fuel injection system which has such a fuel injector arrangement 1 is preferably set up to set a pressure level in the barrier fluid sealing system 61 which is above a fuel gas supply pressure level in the range from 10 bar to 30 bar. Thus it can be prevented that much

Locking fluid flows into the fuel gas area, but at the same time a reliable seal by means of the barrier fluid seals 63, 87 are effected.

In the context of the present invention, a pressure regulating device 81 can be provided both in the fuel injector 3 and also outside the fuel injector 3. The external accommodation can be, for example, above a single-pressure accumulator of the

Fuel injector 3 done, especially when using larger build variable controllable pressure regulating valves. With regard to the pressure regulating device 81, this can be relieved, so that their size can be kept advantageously small when adjusted over the design of the piston gap 57 Vorordelung is set so that the pressure regulating device 81 only needs to control low flow rates for pressure adjustment in Sperrfluiddichtungssystem.

LIST OF REFERENCE NUMBERS

1 fuel injector arrangement

3 Fuel injector

5 injector housing

7 nozzle body

9 Covering element

11 Further housing element

13 fuel gas nozzle valve member

15 valve seat

17 fuel gas nozzle valve

19 fuel gas nozzle chamber

21 fuel gas nozzle arrangement

23 supply line

25 fuel gas inlet

27 fuel gas buffer

29 piston part

29a first section

29b second section

31 valve member part

33 longitudinal median area

35 leadership

37 axial bore

39 control housing

41 hold-down element

43 biasing device

45 leadership

47 first hydraulic control room

49 second hydraulic control room

51 control valve

53 Hydraulic load path

55 Hydraulic unloading path

57 piston guide gap

59 barrier fluid seal chamber Barrier fluid seal system barrier fluid seal

collecting groove

seal

leg

hollow bore

plug member

branch bore

Further puncture drilling

leakage system

Pressure regulating device outflow line

Barrier fluid circuit

Other barrier fluid seal Other barrier fluid seal chamber First line branch

Second line branch

branching point

Claims

A fuel injector assembly (1) having a fuel injector (3) for operation with fuel gas, wherein

- The fuel injector (1) has a fuel gas nozzle valve member (13) having a piston member (29) and a valve member part (31), wherein the piston member (29) is housed in a housing (39) and therein a first (47) and dividing a second (49) hydraulic control chamber in a volume-variable manner; in which

the fuel injector (3) is arranged to divert gap leakage from a piston guide gap (57) about the piston part (29) into a barrier fluid seal chamber (59) of a barrier fluid seal system (61) of the fuel injector (3) formed around the valve member part (31)

Barrier fluid seal (63) on the valve member part (31) to form.

2. Fuel injector arrangement (1) according to claim 1,

characterized in that

the fuel injector (3) for the diversion of the gap leakage has a collecting groove (65) around the piston part (29); and or

- The fuel injector (3) for the diversion of the gap leakage has a line branch (69), which with the gap leakage from the piston guide gap (57) can be flowed against and is guided to the Sperrfluiddichtkammer (59).

3. Fuel injector arrangement (1) according to one of the preceding claims,

characterized in that

the fuel injector (3) for the diversion of the gap leakage has a collecting groove (65) which is formed as an annular groove on the piston part (29), wherein the fuel gas

Nozzle valve member (13) through the piston member (29) and a longitudinally-central portion of the valve member member (31) has a hollow bore (71), by means of which the collecting groove (65) and the Sperrfluiddichtkammer (59) are communicatively connected.

4. fuel injector arrangement (1) according to claim 3,

characterized in that

that the piston member (29) has a sealing ring (67) which is arranged between the collecting groove (65) and the valve member part side piston part end against the peripheral wall around the piston member (29) sealingly thereon; and or 15, the piston member (29) has a first portion (29a) of relatively smaller cross-section which extends from a nozzle distal end to the collecting groove (65) and the piston member (29) further comprises a second portion (29b) of relatively larger cross-section which extends from the collecting groove (65) to a nozzle near end of the piston member (29).

5. fuel injector assembly (1) according to any one of claims 1 and 2,

characterized in that

the fuel injector (3) for the diversion of the gap leakage has a collecting groove (65) which is formed in a housing peripheral wall around the piston member (29), wherein a channel in an injector (5), the collecting groove (65) and the

Blocking fluid sealing chamber (59) connects communicating.

6. Fuel injector arrangement (1) according to one of the preceding claims,

characterized in that

- The barrier fluid seal system (61) to a leakage system (79) of the fuel injector (3) is communicatively connected, in particular downstream.

7. Kraftstoffinjektoranordnung (1) according to claim 6,

characterized in that

- The barrier fluid sealing system (61) via a pressure regulating device (81) to the

Leakage system (79) of the fuel injector (1) communicatively connected.

8. Kraftstoffinjektoranordnung (1) according to any one of the preceding claims,

characterized in that

the fuel injector (1) has at least one further barrier fluid seal (87) which is supplied with barrier fluid via the barrier fluid seal system (61).

9. fuel injector arrangement (1) according to claim 8,

characterized in that

- The further barrier fluid seal (87) between a fuel gas side and a

Hydraulic side of a gap guide (45) is formed around a guided element (41).

10. fuel injection system, 16 characterized in that

the fuel injection system comprises at least one fuel injector arrangement (1) according to one of the preceding claims.

11. Kraftstoffeinspritzsy system (1) according to claim 10 and claim 7;

characterized in that

the fuel injection system is arranged to set a pressure level in the barrier fluid sealing system (61) by means of the pressure regulating device (81), which is in the range of 10 bar to 30 bar above a fuel gas supply pressure.

12th internal combustion engine,

characterized in that

the internal combustion engine comprises a fuel injector arrangement (1) according to one of claims 1 to 9 or a fuel injection system according to one of claims 10 and 11.