FI126732B

FI126732B - The fuel injector

Info

Publication number: FI126732B
Application number: FI20135208A
Authority: FI
Inventors: Stefan Kern; Harald Wellenkötter; Werner Wörle
Original assignee: Man Diesel & Turbo Se
Priority date: 2012-03-07
Filing date: 2013-03-05
Publication date: 2017-04-28
Also published as: KR20130102489A; JP2015509568A; JP6068516B2; DE102012203621A1; FI20135208A; CN103306876A; KR101941714B1; CN103306876B; WO2013131652A1

Description

Fuel injector

The invention relates to a multi-part fuel injector for an internal combustion engine.

Internal combustion engines known from practice, such as for example marine diesel engines, comprise a plurality of cylinders of which each is assigned as least one fuel injector in order to feed fuel to the respective cylinder. Such fuel injectors are mostly constructed of a plurality of parts or components longitudinally assembled one after the other, which have to be set or fixed in a certain alignment (e.g. with respect to their longitudinal axis and their turned position) relative to one another.

In the case of fuel injectors known from practice, this relative alignment of the plurality of components with respect to one another is effected by means of so-called fitted pins, which engage into fitted pin bores of the components. From DE 2 309 134 A such a multi-part fuel injector is known for example, wherein a nozzle construction is aligned with respect to a nozzle holder through a fitted pin.

However, fitted pins have the disadvantage that these break off or shear off easily as a result of a mechanical overloading during the assembly or disassembly of the fuel injector, which as a rule requires extensive repair work on the individual components, in particular with respect to removing the destroyed fitted pins. A further disadvantage of the fitted pins consists in that, because the fitted pin bores receiving the fitted pins are usually introduced in sealing surfaces between the components, the fitted pins after their assembly protrude from the sealing surfaces, which is why for reworking (e.g. lapping) of the sealing surfaces the fitted pins first have to be removed with major effort.

The invention is based on the object of providing a multi-part fuel injector, wherein its components are aligned with respect to one another in a simpler and more maintenance-friendly manner.

This is achieved with a fuel injector according to Claim 1. Further developments of the invention are defined in the dependent claims.

According to the invention, a fuel injector comprises, as the plurality of components connected to one another, an injection nozzle for injecting fuel, a switching valve for controlling the injecting of fuel and a connecting sleeve, which is arranged between the injection nozzle and the switching valve, wherein the injection nozzle at a longitudinal end portion of the latter has a predefined outer nozzle contour and the switching valve on a longitudinal end portion of the latter has a predefined outer valve contour, and wherein the connecting sleeve has a predefined inner sleeve contour, into which the injection nozzle with its outer nozzle contour is positively fitted from a first longitudinal end of the connecting sleeve, so that the injection nozzle is set in a defined alignment with respect to the connecting sleeve, and into which the switching valve with its outer valve contour is positively fitted from a second longitudinal end of the connecting sleeve, so that the switching valve is set in a defined alignment with respect to the connecting sleeve.

In other words, the outer valve contour is positively adapted to the inner sleeve contour, so that a first positive shaft-hub connection as alignment means is created, and the outer nozzle contour is positively adapted to the inner sleeve contour, so that a second positive shaft-hub connection as alignment means is created. Accordingly, the outer valve contour and the outer nozzle contour are each formed complementarily to the inner sleeve contour.

The axial cohesion of the individual components of the fuel injector is ensured, as is usual in the prior art, for example through one or a plurality of union nuts, which act on corresponding ring collars and external threads of the components.

Through the positive fitting-together of the outer nozzle contour and the outer valve contour with the inner sleeve contour according to the invention, the components of the fuel injector are aligned with respect to one another in a particularly simple and maintenance-friendly manner.

If the components of the fuel injector have to be disassembled and reworked if required, merely the shaft-hub connections have to be disconnected by way of pulling the individual components out of the connecting sleeve after the axial cohesion has been disconnected. No fitted pins have to be removed for reworking the sealing surfaces.

With the shaft-hub connections realised via polygon profiles, the fuel injector according to the invention is significantly less sensitive with respect to a mechanical load so that during the assembly and disassembly there is less risk of damaging the alignment means.

Furthermore, through the component embodiment described above, the transmission of a substantially greater tightening torque with for example the union nut(s) is possible, which in view of constantly increasing injection pressures is increasingly required in order to achieve an adequate tightness.

Preferably, the connecting sleeve is dimensioned or configured so that it forms the weakest part of the components. Thus, in the case of mechanical overloading, merely the connecting sleeve is destroyed or damaged, so that only the latter has to be replaced in a simple manner and without various tools.

According to an embodiment of the invention, the inner sleeve contour, on a longitudinal end portion of the latter fitted together with the outer nozzle contour can have another diameter than on a longitudinal end portion fitted together with the outer valve contour of the latter. This configuration of the invention has the advantage that the components injection nozzle and switching valve can be dimensioned taking into account the space conditions and can nevertheless be fitted into the joint connecting sleeve.

According to a further embodiment of the invention, the outer nozzle contour and the outer valve contour are positively fitted into the inner sleeve contour so that the injection nozzle and the switching valve are each aligned with respect to their longitudinal axis and their turned position in a defined manner with respect to the connecting sleeve, which in particular is a centring connecting sleeve.

In other words, the longitudinal axes of the injection nozzle and of the switching valve are aligned or centred with respect to one another through the shaft-hub connections with respect to the longitudinal axis of the connecting sleeve and thus with respect to each other and additionally in their respective turned positions about the longitudinal axes and thus with respect to one another.

According to yet another embodiment of the invention, the inner sleeve contour has a polygon shape. Such a polygon shape, such as will then also have to be created or be present in a complementary manner on the outer nozzle contour and on the outer valve contour, can be produced for example through out-off-round turning or out-off-round grinding or through milling.

Preferably, the polygon shape is formed at least triangularly (such as for example in equal thickness shape P3G according to DIN 32711) and in particular hexagonally or heptagonally.

According to an embodiment of the invention, the inner sleeve contour is formed symmetrically with respect to the longitudinal axis of the connecting sleeve.

In this case, a first protrusion-recess fit is preferably provided between the inner sleeve contour and the outer nozzle contour, which defines a single possible turned alignment of the injection nozzle with respect to the connecting sleeve, and between the inner sleeve contour and the outer valve contour a second protrusion-recess fit is provided, which defines a single possible turned alignment of the switching valve with respect to the connecting sleeve.

In this way, an unambiguous turned positioning between the injection nozzle, the switching valve and the connecting sleeve is created.

According to an alternative embodiment of the invention, the inner sleeve contour is formed unsymmetrically with respect to a longitudinal axis of the connecting sleeve.

In this case, the polygon shape having a plurality of sides preferably comprises at least one side which has another length than the other sides of the polygon shape. Also preferably, the polygon shape comprises a first side which has a shorter length than the other sides of the polygon shape, and comprises a second side, which has a greater length than the other sides of the polygon shape.

In this way, an unambiguous turned positioning between the injection nozzle, the switching valve and the connecting sleeve is also created here.

According to yet another embodiment of the invention, a fuel orifice is positively fitted into the inner sleeve contour between injection nozzle and switching valve. In other words, an outer orifice contour is positively adapted to the inner sleeve contour or formed complementarily to the inner sleeve contour, so that a third positive shaft-hub connection is created.

Between the outer orifice contour and the inner sleeve contour, a protrusion-recess fit can be provided in the case of a symmetrical formation with respect to the longitudinal axis of these. The case of an unsymmetrical formation of the inner sleeve contour with respect to the longitudinal axis, the outer orifice contour merely has to be formed complementarily to said inner sleeve contour.

Thus, an unambiguous turned positioning with respect to the other components of the fuel injector is also achieved with respect to the fuel orifice.

Preferably, all shaft-hub connections or positive fits are embodied as slight clearance fit or as transition fit.

According to the invention, an internal combustion engine, in particular a marine diesel engine, with a fuel injector according to one, a plurality or all previously described embodiments of the invention in any conceivable combination is provided.

In conclusion, a centring and unambiguous positioning (i.e. a defined alignment) of the injection nozzle and if applicable of the fuel orifice on the switching valve of a fuel injector with switching valve is provided according to embodiments of the invention, wherein the alignment is accomplished by means of a polygon profile.

Through the centring sleeve or connecting sleeve as connecting piece between the injection nozzle, the switching valve and if applicable the fuel orifice of a fuel injector with switching valve, fitted pins become superfluous. Because of this, the number of parts additionally required for the alignment is reduced from four to one.

The braking-off or shearing-off of fitted pins in the case of mechanical overloading during the disassembly or assembly resulted in an extensive repair of the switching valve or of the injection nozzle during the removal of the destroyed fitted pins. In the case of mechanical overloading of the connecting sleeve, by contrast, the replacement is possible without additional tools.

By embodying the polygon profile as an axially symmetrical geometry with a protrusion-recess fit (such as for example an arrangement of a fitted pin and an associated fitted pin recess transversely to the longitudinal direction of the connecting sleeve) or as unsymmetrical geometry, an unambiguous positioning or alignment of the injection nozzle, the fuel orifice and the switching valve is possible.

The fitted pins of the prior art have frequently proved to be overloaded in practice. With same size of the injection nozzle, a higher torque can be transmitted via the polygon connection than via the fitted pins previously used in the prior art.

The alignment (preferably including centring) of the injection nozzle with respect to the fuel orifice and the switching valve is carried out by means of a polygonal shaft-hub connection, such as for example the shaft-hub connection polygon profile P3G (DIN 32711). Through slightly different modification of the radii on at least two corners of the at least triangular polygon profile or by creating an axially symmetrical profile with a centring pin or an unsymmetrical profile, such as for example a hexagon having at least one shortened side L-Y and at least one extended side L+X (preferably X=Y), an inadvertently incorrect assembly, which would be possible for example through a 120° turn about the longitudinal axis of the components of the fuel injector, can be excluded. Thus, the omission of the fitted pins in their original form is possible.

The invention expressly extends also to such embodiments as do not materialise through feature combinations from explicit references of the claims, wherein the disclosed features of the invention - insofar as technically practical - can be combined with one another as desired.

In the following, the invention is described by means of preferred embodiments and making reference to the attached Figures.

Fig. 1 shows a perspective exploded view of a fuel injector according to an embodiment of the invention.

Fig.2 shows a perspective view of a connecting sleeve of a fuel injector according to a further embodiment of the invention.

Fig.3 shows a cross-sectional view or front view of the connecting sleeve from Fig.2.

Fig.4 shows a longitudinal sectional view of the connecting sleeve from Fig. 2, seen along a ling A-A in Fig.3.

Fig. 1 shows a perspective exploded view of a fuel injector 1 formed according to a first embodiment of the invention of an internal combustion engine (not shown completely) here designed as a marine diesel engine.

The fuel injector 1 comprises an injection nozzle 10 for injecting fuel (in this case diesel fuel), a switching valve 20 for controlling (permitting/blocking) the injecting of fuel and a connecting sleeve or centring sleeve 30, which is arranged between the injection nozzle 10 and the switching valve 20.

On a longitudinal end portion 11 of the injection nozzle 10 facing the connecting sleeve 30, the injection nozzle 10 has a predefined outer nozzle contour 12 and the switching valve 20 has a predefined outer valve contour 22 on a longitudinal end portion 21 of said switching valve 20 facing the connecting sleeve 30.

The connecting sleeve 30 in turn has a predefined inner sleeve contour 33, into which the injection nozzle 10 with its outer nozzle contour 12 is positively fitted from a first longitudinal end 31 of the connecting sleeve 30, so that the injection nozzle 10 is set in a defined alignment with respect to the connecting sleeve 30.

In the inner sleeve contour 33, the switching valve 20 with its outer valve contour 22 is additionally positively fitted from a second longitudinal end 32 of the connecting sleeve 30, so that the switching valve 20 is set in a defined alignment with respect to the connecting sleeve 30.

In other words, the outer valve contour 22 is positively adapted to the inner sleeve contour 33, so that a first positive shaft-hub connection as alignment means is created, and the outer nozzle contour 12 is positively adapted to the inner sleeve contour 33, so that a second positive shaft-hub connection as alignment means is created. Accordingly, the outer valve contour 12 and the outer nozzle contour 22 are each formed complementarily to the inner sleeve contour 33.

In addition, a fuel orifice 40 set in a defined alignment with respect to the connecting sleeve 30 is positively fitted into the inner sleeve contour 33 between injection nozzle 10 and switching valve 20.

In other words, an outer orifice contour 41 of the fuel orifice 40 is positively adapted to the inner sleeve contour 33 or formed complementarily to the inner sleeve contour 33, so that a third positive shaft-hub connection as alignment means is created.

Preferably, all shaft-hub connections or positive fits are embodied as slide clearance fit or as transition fit.

As is evident from Fig. 1, the injection nozzle 10 has a longitudinal axis L1, the switching valve 20 a longitudinal axis L2, the connecting sleeve 30 a longitudinal axis L3 and the fuel orifice 40 a longitudinal axis L4.

According to the invention, the outer nozzle contour 12, the outer valve contour 22 and the outer orifice contour 41 are positively fitted into the inner sleeve contour 33 so that the injection nozzle 10, the switching valve 20 and the fuel orifice 40 are each aligned defined with respect to the connecting sleeve 30 with respect to their longitudinal axis L1, L2 and L4 respectively and their turned position about the respective longitudinal axis L1, L2 and L4 respectively. In other words, the longitudinal axes L1, L2 and L4 respectively of the injection nozzle 10, of the switching valve 20 and of the fuel orifice 40 are aligned with the shaft-hub connections with respect to the longitudinal axis L3 of the connecting sleeve 30 and thus with respect to one another and additionally in their respective turned positions about the longitudinal axes L1, L2 and L4 respectively and thus with respect to each other or centred.

To realise the alignment, the outer valve contour 12, the outer nozzle contour 22 and the outer orifice contour 41 each have a polygon shape and the inner sleeve contour 33 has a polygon shape that is complementary to these outer contours (outer valve contour 12, outer nozzle contour 22 and outer orifice contour 41). The inner and outer polygon shapes can be produced for example through out-off-round turning or out-off-round grinding or through milling.

According to the invention, the respective polygon shapes of the components of the fuel injector 1 are formed at least triangularly and according to Fig. 1 in particular heptagonally.

The axial (in the longitudinal direction) cohesion of the individual components of the fuel injector 1 is ensured, as is usual in the prior art, for example through one or a plurality of union nuts (not shown), which act on corresponding ring collars (such as for example a ring collar 13 of the injection nozzle 10) and external threads (not shown) of the components.

According to an embodiment of the invention, the inner sleeve contour 33, although not so shown in Fig. 1, on a longitudinal end portion 31.1 of the latter fitted together with the outer nozzle contour 12, can have another inner diameter than on a longitudinal end portion 32.1 fitted together with the outer valve contour 22 of the latter. This configuration of the invention has the advantage in particular, that it is possible to dimension the components injection nozzle 10 and switching valve 20 subject to taking into account the space conditions while it is possible to fit these into the joint connecting sleeve 30.

As is evident from Fig. 1, the respective polygon shapes (outer valve contour 12, outer nozzle contour 22, inner sleeve contour 33 and outer orifice contour 41) of the components of the fuel injector 1 are in each case formed unsymmetrical with respect to their longitudinal axis L1, L2, L3 and L4 respectively in order to ensure an unambiguous turned positioning between the injection nozzle 10, the switching valve 20, the fuel orifice 40 and the connecting sleeve 30. In other words, the components of the fuel injector 1 can each be only inserted in a single predefined turned position in the connecting sleeve 30.

In detail, each polygon shape has a plurality of sides S, S’, S” and corners E connecting these and at least one side S’, S” (in Fig. 1 three sides), which has another length than the other sides S of the polygon shape.

According to Fig. 1, each polygon shape has three sides S’, S”, which have a shorter length than the other sides S of the polygon shape, wherein a side S” of these sides S’, S” formed with a shorter length has a shorter length than the other sides S’ of the these sides S’, S” of the polygon shaped formed with shorter length.

Figures 2 to 4 show views of a connecting sleeve 30a formed according to a second embodiment of the invention of a fuel injector 1a (not completely shown) of an internal combustion engine (not completely shown) formed as a marine diesel engine.

The fuel injector 1a according to the second embodiment of the invention is formed identically to the fuel injector 1 according to the first embodiment of the invention except for a few differences. For this reason, in the following, only these differences are shown, wherein same or similar components as in Fig. 1 are marked with same or similar reference characters, and wherein the reference characters of modified components the small character “a” is suffixed. As is evident from the Figures 2-4, the respective polygon shapes of the components of the fuel injector 1a are formed at least triangularly and here in particular hexagonally.

The respective polygon shapes (outer valve contour, outer nozzle contour, inner sleeve contour 33a and outer orifice contour) of the components of the fuel injector 1a are again each formed unsymmetrically with respect to their longitudinal axis in order to ensure an unambiguous turned positioning between the injection nozzle, the switching valve, the fuel orifice and the connecting sleeve 30a. Thus, the components of the fuel injector 1a can each be inserted in the connecting sleeve 30a only in a single predefined turned positioning. In detail, each polygon shape of the components of the fuel injector 1a has a plurality of sides S, S’, S” and corners E connecting these and at least one side S’, S” (in the Figures 2-4 two sides), which has another length than the other sides S of the polygon shape.

According to the Figures 2-4, each polygon shape of the components of the fuel injector 1 a has a first side S”, which has a shorter length (L-Y) than the other sides S of the polygon shape, and a second side S’ which has a greater length (L+X) than the other sides S (with the length dimension L) of the polygon shape. Preferably, the length dimension X is equal to the length dimension Y.

According to modifications of the first and second embodiment of the invention which is not shown in the Figures, the respective polygon shapes (outer valve contour, outer nozzle contour, inner sleeve contour and outer orifice contour) can be formed symmetrically with respect to their longitudinal axes.

In this case, a first protrusion-recess fit is provided between the inner sleeve contour and the outer nozzle contour, which defines a single possible turned alignment of the injection nozzle with respect to the connecting sleeve. Furthermore, a second protrusion-recess fit is provided between the inner sleeve contour and the outer valve contour, which defines a single possible turned alignment of the switching valve with respect to the connecting sleeve. Finally, a protrusion-recess fit is then also provided between the outer orifice contour and the inner sleeve contour, which defines a single possible turned alignment of the fuel orifice with respect to the connecting sleeve.

Each protrusion-recess fit can for example be formed in the form of an arrangement of a fitted pin recess extending in terms of depth transversely to the longitudinal axis (of injection nozzle, switching valve and fuel orifice) in the respective outer contours and a fitted pin protruding transversely to the longitudinal axis towards radially inside from the inner sleeve contour engaging in the fitted pin recess). Preferably, the fitted pin recess has an open end in longitudinal direction of the respective component, via which the fitted pin during the inserting of the component in the connecting sleeve, can be inserted in the respective fitted pin recess.

List of reference characters I Fuel injector 1a Fuel injector 10 Injection nozzle II Longitudinal end portion 12 Outer nozzle contour 13 Ring collar 20 Switching valve 21 Longitudinal end portion 22 Outer valve contour 30 Connecting sleeve 30a Connecting sleeve 31 Longitudinal end 31.1 Longitudinal end portion 31.1a Longitudinal end portion 32 Longitudinal end 32.1 Longitudinal end portion 32.1a Longitudinal end portion 33 Inner sleeve contour 33a Inner sleeve contour 40 Fuel orifice 41 Outer orifice contour L1, L2 Longitudinal axis L3, L4 Longitudinal axis L Length dimension X, Y Length dimension S, S', S" Side E Corner

Claims

Patent claims

1. A fuel injector (1; 1a) having an injection nozzle (10) for injecting fuel, a switching valve (20) for controlling the injecting of fuel and a connecting sleeve (30; 30a), which is arranged between the injection nozzle (10) and the switching valve (20), wherein the injection nozzle (10) on a longitudinal end portion (11) of said injection nozzle (10) has a predefined outer nozzle contour (12) and the switching valve (20) on a longitudinal end portion (21) of said switching valve (20) has a predefined outer valve contour (22), and wherein the connecting sleeve (30, 30a) has a predefined inner sleeve contour (33; 33a), into which the injection nozzle (10) from a first longitudinal end (31) of the connecting sleeve (30, 30a) can be positively fitted with its outer nozzle contour (12) so that the injection nozzle (10) is set in a defined alignment with respect to the connecting sleeve (30, 30a), and into which the switching valve (20) from a second longitudinal end (32) of the connecting sleeve (30, 30a) can be positively fitted into with its outer valve contour (22) so that the switching valve (20) is set in a defined alignment with respect to the connecting sleeve (30, 30a), wherein the inner sleeve contour (33; 33a) has a polygon shape, and wherein the polygonal shape has a plurality of sides (S, S’, S”), characterized in that the inner sleeve contour (33; 33a) is formed unsym-metrically with respect to a longitudinal axis (L3) of the connecting sleeve (30; 30a) and at least one side (S’, S”), the polygon shape has another length than the other sides (S) of the polygon shape.
2. The fuel injector (1; 1a) according to claim 1, wherein the outer nozzle contour (12) and the outer valve contour (22) positively fitted into the inner sleeve contour (33; 33a) so that the injection nozzle (10) and the switching valve (20) in each case with respect to their longitudinal axis (L1, L2) and their turned position, are aligned defined with respect to the connecting sleeve (30, 30a).
3. The fuel injector (1; 1a) according to claim 1 or 2, wherein the polygon shape is formed at least triangularly, in particular hexagonally or heptago-nally.
4. The fuel injector (1; 1a) according to any one of claims 1 to 3, wherein the inner sleeve contour (33; 33a) is formed symmetrically with respect to a longitudinal axis (L3) of the connecting sleeve (30, 30a).
5. The fuel injector (1; 1a) according to claim 4, wherein between the inner sleeve contour (33, 33a) and the outer nozzle contour (12) a first protrusion-recess fit is provided, which defines a single possible turned alignment of the injection nozzle (10) with respect to the connecting sleeve (30; 30a), and wherein between the inner sleeve contour (33; 33a) and the outer valve contour (22) a second protrusion-recess fit is provided, which defines a single possible turned alignment of the switching valve (20) with respect to the connecting sleeve (30; 30a).
6. The fuel injector (1; 1a) according to any one of claims 1 to 5, wherein the polygon shape has a first side (S”), which has a shorter length than the other sides (S) of the polygon shape, and has a second side (S’) which has a greater length than the other sides (S) of the polygon shape.
7. The fuel injector (1; 1a) according to any one of the claims 1 to 6, wherein between injection nozzle (10) and switching valve (20) a fuel orifice (40) is positively fitted into the inner sleeve contour (33; 33a).
1. Polttoaineinjektori (1; 1a), jossa on ruiskutussuutin (10) polttoaineen ruiskuttaniiseksi, kytkentäventtiili (20) polttoaineen ruiskutuksen ohjaamiseksi ja liitosholkki (30; 30a), joka on sovitettu ruiskutussuuttimen (10) ja kyt-kentäventtiilin (20) välille, jolloin ruiskutussuuttimella (10) on sen pitkittäispäätyosassa (11) ennalta määrätty suuttimen ulkomuoto (12) ja kytkentäventtiiIillä (20) on sen pitkittäispäätyosassa (21) ennalta määrätty venttiilin ulkomuoto (22), ja jolloin liitosholkilla (30; 30a) on ennalta määrätty hoikin sisämuoto (33; 33a), johon liitosholkin (30; 30a) ensimmäisessä pitkittäispäässä (31) ruiskutussuutin (10) on suuttimen ulkomuotonsa (12) avulla sovitettu muotosulkei-sesti, niin että ruiskutussuutin (10) on kiinnitetty määrätyssä asennossa liitos-hoikkiin (30; 30a), ja johon liitosholkin (30; 30a) toisessa pitkittäispäässä (32) kytkentäventtiili (20) on venttiilin ulkomuotonsa (22) avulla sovitettu muotosul-keisesti, niin että kytkentäventtiili (20) on kiinnitetty määrätyssä asennossa lii-tosholkkiin (30; 30a), jolloin hoikilla (30; 30a) on polygonimuoto, ja jolloin po-lygonimuodolla on useita sivuja (S, S’, S”), tunnettu siitä, että hoikin sisämuoto (33; 33a) on muodostettu epäsymmetriseksi liitosholkin (30; 30a) pituusakselin (L3) suhteen ja vähintään yksi polygonimuodon sivu (S’, S”), on eripituinen kuin polygonimuodon muut sivut (S).
2. Patenttivaatimuksen 1 mukainen polttoaineinjektori (1; 1a), jolloin suuttimen ulkomuoto (12) ja venttiilin ulkomuoto (22) on sovitettu hoikin sisä-muotoon (33; 33a) muotosulkeisesti siten, että ruiskutussuutin (10) ja kytkentäventtiili (20) on kulloinkin suunnattu pituusakselinsa (L1, L2) ja kiertoasemansa suhteen määrätyllä tavalla liitosholkin (30; 30a) suhteen.
3. Patenttivaatimuksen 1 tai 2 mukainen polttoaineinjektori (1; 1a), jolloin polygonimuoto on muodostettu vähintään kolmikulmaiseksi, erityisesti kuusikulmaiseksi tai seitsenkulmaiseksi.
4. Jonkin patenttivaatimuksen 1 - 3 mukainen polttoaineinjektori (1; 1a), jolloin hoikin sisämuoto (33; 33a) on muodostettu symmetriseksi liitosholkin (30; 30a) pituusakselin (L3) suhteen.
5. Patenttivaatimuksen 4 mukainen polttoaineinjektori (1; 1a), jolloin hoikin sisämuodon (33; 33a) ja suuttimen ulkomuodon (12) välille on järjestetty ensimmäinen ulkonema-syvennys-sovitus, joka määrittää ruiskutussuuttimen (10) yhden ainoan mahdollisen kiertosuunnan liitosholkin (30; 30a) suhteen, ja jolloin hoikin sisämuodon (33; 33a) ja venttiilin ulkomuodon (22) välille on järjestetty toinen ulkonema-syvennys-sovitus, joka määrittää kytkentäventtiilin (20) yhden ainoan mahdollisen kiertosuunnan liitosholkin (30; 30a) suhteen.
6. Jonkin patenttivaatimuksen 1 - 5 mukainen polttoaineinjektori (1a), jolloin polygonimuodolla on ensimmäinen sivu (S”), jolla on pienempi pituus kuin polygonimuodon muilla sivuilla (S) ja toinen sivu (S’), jolla on suurempi pituus kuin polygonimuodon muilla sivuilla (S).
7. Jonkin patenttivaatimuksen 1 - 6 mukainen polttoaineinjektori (1; 1a), jolloin hoikin sisämuotoon (33; 33a) ruiskutussuuttimen (10) ja kytkentäventtiilin (20) väliin on sovitettu muotosulkeisesti polttoaineen kuristin (40).