DE102015016034B3 - fuel injector - Google Patents

Abstract

A fuel injector assembly (1) having a fuel injector (3) for operation with fuel gas, wherein - the fuel injector (1) comprises a fuel gas nozzle valve member (13) having a piston member (29) and a valve member member (31), the piston member (29) is housed in a housing (39) and divides a first (47) and a second (49) hydraulic control space in a volume-variable manner therein; wherein - the fuel injector (3) is arranged to divert gap leakage from a piston guide gap (57) around the piston member (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 member (31) Barrier fluid seal (63) on the valve member part (31) to form.

Description

The present invention relates to a fuel injector assembly 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 fuel gas needle guides or valve member guides owed.

In this context, the document shows DE 10 2013 017 853 A1 a dual-fuel fuel injection system including a fuel gas fuel injector having a nozzle needle around which a leakage collection space is formed along a leakage creeping gap, the leakage collection space cooperating with a pressure regulating device. The pamphlets DE 11 2012 003 567 T5 and DE 11 2012 004 430 T5 next to each disclose a dual fuel injector with a hydraulically locking seal on a leakage creep around a fuel gas needle valve member, which is formed by means of a check valve. This prevents hydraulic fluid from flowing over at low fuel gas pressure in a fuel gas nozzle chamber.

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 can be a single-fuel injector, which in particular controls a hydraulic control circuit a fuel gas nozzle valve member has, alternatively and preferably, a dual-fuel fuel injector, which can also eject 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 fuel injector assembly having a fuel injector as discussed above is preferably part of a common rail fuel injector.

In general, the Kraftstoffinjektoranordnung z. B. 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, for. B. for a combined heat and power plant, an (emergency) generator, z. B. 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, particularly 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 can. The piston part is furthermore intended to effect a stroke control of the fuel gas nozzle valve member in the context of a hydraulic piston control device, i. H. 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 (nozzle-remote end side) arranged, for. B. formed or integrally formed therewith, for example as (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 lid member thereof) and distributes a variable volume therein first and second hydraulic control chambers. 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 on hochdruckbeaufschlagtes Hydraulic fluid with pressure levels of z. B. 380 bar to 550 bar is provided.

Generally preferred here 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 hereby be closer to the nozzle, the second hydraulic control chamber to be 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 seal chamber (in particular annular chamber) of a barrier fluid seal system of the injector formed around the valve member part, to form a barrier fluid seal on the injector Valve member part to form.

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 in the hydraulic control circuit along a guide of the valve member part, d. H. by means of (blocking) fluid on the guide locks. Here, the invention can continue to make advantageous advantage 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 education the barrier fluid seal is advantageously preset.

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 redirect the gap leakage sufficiently reliably to the barrier fluid seal is proposed in a preferred embodiment of the Kraftstoffinjektoranordnung that the fuel injector for the diversion of the gap leakage has a collecting groove around the piston part. Such collecting groove is preferably an annular groove, wherein in the collecting groove z. B. stripped by the housing wall Spaltleckage can be introduced. In order to continue to spend the gap leakage from the collecting groove to the Sperrfluiddichtkammer, the fuel injector may have a line branch for the diversion of the gap leakage, z. B. a specially formed drilling channel, which can be flowed over the collecting groove and is guided to the barrier fluid seal 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. About z. B. a further radial tap hole, starting from the hollow bore - formed at the other end of the hollow bore - then the Sperrfluiddichtkammer with flowing out of the hollow bore barrier fluid (gap leakage) are supplied or supplied. An open (Bohrwerkzeug-) inlet end of the hollow bore, which is preferably formed remote from the nozzle on the piston part, in this case can be closed with a closure element or a plug.

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 sealing 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 collection groove z. B. Slip off leakage from the piston part, d. H. for supply to the barrier fluid seal chamber. However, such an embodiment requires an internal processing of the housing peripheral wall and could be more expensive to manufacture in this regard. A conduit branch or channel communicating the collecting groove and the barrier fluid sealing chamber could in this case in an injector housing element, for. B. 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 is still preferably a pressurizable with closing pressure control chamber, that is, a control room, which over the vast period of operation - to comply with Closed position of the fuel gas nozzle valve member - pressurized or loaded. 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 barrier fluid system is connected in a communicating manner 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 sealing chamber via a line connection to the leakage system can be absteuerbar which z. B. has a throttle device, for. B. 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 for example regulated 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). A possible overflow of barrier fluid in the fuel gas part of the fuel injector via a valve member part guide in a fuel gas nozzle chamber can here be regarded as irrelevant, since this is simply mitverraucht in 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 discharge line from the barrier fluid sealing chamber can branch around the valve member part, which leads via the pressure regulating device to the leakage system of the fuel injector, in particular upstream of the pressure regulating device, whereby the further barrier fluid seal can be supplied with barrier fluid via the branch. 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 resiliently exerts a closing force on the fuel gas nozzle valve member, in particular on the piston member and, for example, on a fuel gas passage and / or storage space, e.g. B. provided as a fuel gas buffer is received.

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, which shows details essential to the invention, 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 exemplary and schematically a Kraftstoffinjektoranordnung 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 exemplary and schematically a fuel injector 1 with a fuel injector 3 for operation with fuel gas, the fuel injector 3 can be set up as a single-fuel or as a dual-fuel fuel injector, ie in design as a dual-fuel fuel injector for a liquid fuel z. B. in the context of a Zündstrahlverfahrens or for a pure liquid fuel operation.

The fuel injector 3 has an injector housing 5 which is formed by means of a number of housing elements, for example by means of a nozzle body 7 , continue to the nozzle body 7 lidding element 9 as an intermediate plate or another housing element 11 ,

In the nozzle body 7 is a fuel gas nozzle valve member 13 of the fuel injector 3 taken up, which against a valve seat 15 acts, ie together with this a fuel gas nozzle valve 17 of the fuel injector 3 forms. Depending on the stroke position of the fuel gas nozzle valve member 13 can this pressurized fuel gas from a fuel gas nozzle chamber 19 be selectively enabled, ie 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 arrangement 1 a supply line 23 on which of a fuel gas inlet 25 of the fuel injector 3 to the fuel gas nozzle chamber 19 is guided. This can be in the supply line 23 furthermore a fuel gas buffer 27 be formed, for example, provided by a partially enlarged volume in the supply line 23 ,

The fuel gas nozzle valve member 13 now has a piston part 29 and a - subsequent thereto - valve member part 31 on, which are firmly connected to each other, in particular integrally formed. As 1 illustrates is the valve member part 31 formed equal to one or as a nozzle needle, further having a longitudinally central region 33 , At the longitudinal middle area 33 is the valve member part 31 by means of a same comprehensive guide 35 formed by means of a fuel gas nozzle valve member 13 receiving axial bore 37 (in the nozzle body 7 ) tightly or with very little radial play, ie with a radial clearance A1. Over the guided section or the longitudinal middle section 33 has the valve member part 31 in this case a diameter D1.

The piston part 29 or the piston is at a nozzle distal end of the fuel gas nozzle valve member 13 , adjacent to the valve member part 31 , formed, that is, with a diameter which is greater than D1, generally by means of a cross-sectional expansion of the valve member part 31 forming rod-shaped portion of the fuel gas nozzle valve member 13 ,

The piston part 29 is in a (control) housing 39 taken, which by means of a hole in the nozzle body 7 is formed, starting from which the leadership 35 of the valve member part 31 towards the fuel gas nozzle chamber 19 extends away. The housing is capped off the nozzle 39 continue through 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 against the nozzle-distal end of the piston part 29 is urged in plant, ie order for a reliable receipt of the closed position of the fuel gas nozzle valve member 13 to care. At this point it should be noted that the biasing device 43 the hold-down element (compression spring) advantageous in the buffer space 27 of the fuel gas supply line 23 is housed, so no additional space on the fuel injector 3 for the pretensioner 43 is required. It should also be noted that the axially movable stilt element 41 in a (radial) game-prone leadership 45 in the lidding element 9 is guided.

The one in the case 39 recorded piston part 29 share in a first 47 and a second 49 Hydraulic control room volume variable from. The first hydraulic control room 47 which is formed closer to the nozzle, is provided for, under load thereof, an opening pressure on the piston member 29 exercise, the second control room 49 , which is formed nozzle-remote, to the same when it loads a closing pressure on the piston element 29 exercise.

The first 47 and second 49 Hydraulic control room and the piston part 29 formed piston control device 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 as well as a hydraulic fluid discharge path 55 (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 z. B. as a combination of two 3/2-way valves. Depending on the switching position of the control valve 51 can be a hydraulic pressure either on the one hydraulic control room 47 respectively. 49 act (load) while the other hydraulic control room 49 respectively. 47 is relieved to the low pressure side (outflowing hydraulic fluid) or vice versa.

In the switching position shown, for example, the second hydraulic control chamber 49 loaded during the first hydraulic control room 47 is relieved, that is, the fuel gas nozzle valve member 13 is forced into the closed position shown. Will the control valve 51 reversed, the second hydraulic control room 49 be relieved and the first hydraulic control room 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 possible, that is, the fuel gas nozzle valve member 13 is forced into open position. As can be seen with the thus configured piston control device insofar the hub of the fuel gas nozzle valve member 13 hydraulically controlled.

The fuel injector 3 is here also continue - in the invention characterizing way - set up, gap leakage from a piston guide gap 57 around the piston part 29 in one around the valve member part 31 formed barrier fluid seal chamber 59 a barrier fluid seal system 61 of the fuel injector 3 divert to a barrier fluid seal 63 on the valve member part 31 to build.

The barrier fluid seal 63 surrounds the valve member part 31 at the close-knit section 33 or within it, the barrier fluid seal chamber 59 by means of an annular groove - within the axial extent of the guide 35 - in the nozzle body 7 is formed, which against the adjacent valve member part 31 is open. Such is by means of the barrier fluid seal chamber 59 Registered and pressurized hydraulic fluid or barrier fluid in the form of redirected gap leakage overflow of fuel gas from the fuel gas nozzle chamber 19 over the axial bore 37 in the case 39 and thus effectively prevents the hydraulic control circuit.

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

A second section 29b with a relatively larger cross section or a diameter D3 continues to extend from the collecting groove 65 towards the nozzle near end of the piston part 29 or to the first hydraulic control room 47 , Such is a piston guide gap 57 around the piston part 29 formed, which over the first section 29a has relatively wide clearance A2 to the piston peripheral wall and which over the second portion 29b relatively closer clearance A3 has the piston perimeter 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 process even further, thus allowing a faster opening, can around the piston part 29 a sealing ring 67 or piston ring to be arranged, that is, between the collecting groove 65 and the nozzle near the piston part end.

With this configuration, the collecting groove takes 65 predominantly or almost exclusively gap leakage from the piston guide gap 57 on which one over the first section 29a is present, ie when operating the fuel injector 3 regularly pressurized is pending. This is because, on the part of the second or closing pressure hydraulic control chamber 49 over the piston gap 57 to the collecting groove 65 Guided gap leakage over the majority of the operating time shares under hydraulic pressure is or is loaded.

To the gap leakage to the barrier fluid seal chamber 59 redirect, the barrier fluid seal system 61 continue a line branch 69 on, which by means of a hollow bore formed as a blind bore 71 in the fuel gas nozzle valve member 13 is formed. The hollow bore 71 extends over a portion of the nozzle distal end of the piston part 29 into the guided section 33 in (axially) to which the barrier fluid seal 63 is formed. Düsenfern is the hollow bore 71 in this case with a plug element 73 locked.

The hollow bore thus formed 71 can on the part of collecting 65 via at least one radially executed tap hole 75 with the gap leakage (hydraulic fluid) acted upon or be flown, wherein downstream the Sperrfluiddichtkammer 59 via at least one further radially executed tap hole 77 - Over the entire possible Bremgas nozzle valve member position range - with the thus redirected gap leakage fluid can be flowed.

Noteworthy in the context of the arrangement shown here is that on the choice of the width of the piston guide gap on the first section 29a a Vordrosselung, thus a pressure level, is selectively preset, under which or with which the Gap leakage over the collecting groove 65 can be tapped. About the diversion branch 69 The branched off fluid can then without further significant throttling or pressure influencing the barrier fluid seal chamber 59 be supplied.

As 1 Also illustrated, the fuel injector assembly 1 continue a leak system 79 to which the barrier fluid seal system 61 of the fuel injector 3 - Downstream - communicatively connected, in particular via a pressure regulating device 81 , This leads to a discharge line 83 the barrier fluid seal system 61 from the barrier fluid seal chamber 59 towards the pressure regulating device 81 , about which 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 is an adaptation of the pressure level of the barrier fluid seal 63 or in the barrier fluid seal system 61 to a currently prevailing fuel gas supply pressure level, that is, by suitably varied shutdown of barrier fluid into the downstream leakage system 79 (towards the low pressure side).

In the embodiment of the fuel injector shown 3 has the barrier fluid seal system 61 , parallel to the discharge line 83 switched, continue a Sperrfluidkreis 85 over which another barrier fluid seal 87 with barrier fluid from the gap leakage of the piston guide gap 57 is supplied.

The further barrier fluid seal 87 is here - by means of another Sperrfluiddichtkammer 89 - in the leadership 45 received portion of the hold-down element 41 formed around there and causes a seal against fuel gas leakage, which otherwise along the gap guide to the stilt member 41 in the (control) housing 39 could enter, that is from the through the cache 27 formed fuel gas side to the hydraulic side (of the hydraulic control circuit and the piston control device). To form the Sperrfluidkreises 85 with the further or second barrier fluid seal 87 branches a first leg 91 the Sperrfluidkreises 85 from the discharge line 83 (and upstream of the pressure regulating device 81 ) to the further barrier fluid seal chamber 89 From there and causes the intended for the sealing functionality pressure build-up in the other barrier fluid seal chamber 89 by means of the barrier fluid (gap leakage; hydraulic fluid). Outflow from the other barrier fluid seal chamber 89 leads a second leg 93 which is downstream of the branch point 95 of the first branch 91 (and upstream of the pressure regulating device 81 ) back into the discharge line 83 einzweigt.

With this arrangement, it is thus possible via the pressure regulating device 81 the pressure throughout the barrier fluid seal system 61 , thus in both Sperrfluiddichtkammern 59 . 89 or the respective barrier fluid seals 63 . 87 adjust. The fuel injector arrangement is preferred 1 or a fuel injection system including such a fuel injector assembly 1 in this case has set up a pressure level in the barrier fluid sealing system 61 set, which is in the range of 10 bar to 30 bar above a fuel gas supply pressure level. Thus it can be prevented that overflowed much barrier fluid in the fuel gas area, but at the same time a reliable seal by means of the barrier fluid seals 63 . 87 be effected.

A pressure regulating device 81 can in the context of the present invention both in the fuel injector 3 but also outside the fuel injector 3 be provided. The external housing may, for example, above a single pressure accumulator of the fuel injector 3 take place, especially when using larger-sized variable controllable pressure regulating valves. With regard to the pressure regulating device 81 this can be relieved, so their size can be kept advantageously small, if the on the design of the piston gap 57 scored throttling is set so that the pressure regulating device 81 only low volume flow for pressure adjustment abzusteuern in the sealing fluid seal system needs.

LIST OF REFERENCE NUMBERS

1

fuel injector

3

fuel injector

5

injector

7

nozzle body

9

Covering element

11

Another 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 part

31

Valve member part

33

Longitudinal area

35

guide

37

axial bore

39

control housing

41

Down member

43

biasing means

45

guide

47

first hydraulic control room

49

second hydraulic control room

51

control valve

53

Hydraulic load path

55

Hydraulic relief path

57

Piston guide gap

59

Barrier fluid sealing chamber

61

Barrier fluid sealing system

63

Blocking fluid seal

65

collecting groove

67

seal

69

leg

71

hollow bore

73

plug member

75

branch bore

77

Further puncture drilling

79

leakage system

81

pressure regulator

83

outflow

85

Barrier fluid circuit

87

Further barrier fluid seal

89

Other barrier fluid seal chamber

91

First line branch

93

Second line branch

95

branching point

Claims (12)

Fuel injector assembly ( 1 ) with a fuel injector ( 3 ) for operation with fuel gas, wherein - the fuel injector ( 3 ) a fuel gas nozzle valve member ( 13 ) with a piston part ( 29 ) and a valve member part ( 31 ), wherein the piston part ( 29 ) in a housing ( 39 ) and contains a first ( 47 ) and a second ( 49 ) Hydraulic control room divides volume variable; wherein - the fuel injector ( 3 ), gap leakage from a piston guide gap ( 57 ) around the piston part ( 29 ) in a to the valve member part ( 31 ) formed barrier fluid seal chamber ( 59 ) of a barrier fluid sealing system ( 61 ) of the fuel injector ( 3 ) to create a barrier fluid seal ( 63 ) on the valve member part ( 31 ) to build. Fuel injector assembly ( 1 ) According to claim 1, characterized in that - the fuel injector ( 3 ) for the diversion of the gap leakage a collecting groove ( 65 ) around the piston part ( 29 ) having; and / or the fuel injector ( 3 ) for the diversion of the gap leakage a line branch ( 69 ), which with the gap leakage from the piston guide gap ( 57 ) and to the barrier fluid sealing chamber ( 59 ) is guided. Fuel injector assembly ( 1 ) according to one of the preceding claims, characterized in that - the fuel injector ( 3 ) for the diversion of the gap leakage a collecting groove ( 65 ), which as an annular groove on the piston part ( 29 ) is formed, wherein the fuel gas nozzle valve member ( 13 ) through the piston part ( 29 ) and a longitudinally-central portion of the valve member part ( 31 ) a hollow bore ( 71 ), by means of which the collecting groove ( 65 ) and the barrier fluid seal chamber ( 59 ) are communicatively connected. Fuel injector assembly ( 1 ) according to claim 3, characterized in that - the piston part ( 29 ) a sealing ring ( 67 ), which between the collecting groove ( 65 ) and the valve member part side piston part end against the peripheral wall around the piston part ( 29 ) is arranged sealingly on the same; and / or the piston part ( 29 ) a first section ( 29a ) has a relatively smaller cross section, which extends from a nozzle-distal end to the collecting groove ( 65 ) and the piston part ( 29 ) continue a second section ( 29b ) of relatively larger cross-section which extends from the collecting groove ( 65 ) to a nozzle near end of the piston part ( 29 ). Fuel injector assembly ( 1 ) according to one of claims 1 and 2, characterized in that - the fuel injector ( 3 ) for the diversion of the gap leakage a collecting groove ( 65 ), which in a housing peripheral wall around the piston part ( 29 ), wherein a channel in an injector housing ( 5 ) the collecting groove ( 65 ) and the barrier fluid seal chamber ( 59 ) connects communicatively. Fuel injector assembly ( 1 ) according to one of the preceding claims, characterized in that - the barrier fluid sealing system ( 61 ) to a leakage system ( 79 ) of the fuel injector ( 3 ) is connected communicatively, in particular downstream. Fuel injector assembly ( 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 ( 3 ) is communicatively connected. Fuel injector assembly ( 1 ) according to one of the preceding claims, characterized in that - the fuel injector ( 3 ) at least one further barrier fluid seal ( 87 ), which via the barrier fluid sealing system ( 61 ) is supplied with barrier fluid. Fuel injector assembly ( 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 ) around an element ( 41 ) is formed. Fuel injection system, characterized in that - the fuel injection system has at least one fuel injector arrangement ( 1 ) according to one of the preceding claims. A fuel injection system according to claim 10 and claim 7; characterized in that - the fuel injection system is arranged by means of the pressure regulating device ( 81 ) a pressure level in the barrier fluid sealing system ( 61 ), which is in the range of 10 bar to 30 bar above a fuel gas supply pressure. Internal combustion engine, characterized in that - the internal combustion engine has 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.

Images