An injector device, an internal combustion engine and a method of injecting fuel

Abstract

The disclosure relates to an injector device (1) for injecting liquid fuels into a combustion chamber of an internal combustion engine. The injector device comprises an injector needle (3), in the open position of which fuel flow from a primary fuel chamber to an injector nozzle (5) us allowed. Correspondingly, in the closed position of the injector needle (3) fuel flow from the primary fuel chamber (4) to the injector nozzle (5) is interrupted. The needle (3) comprises an internal, secondary fuel passage (3a) one or more needle orifices (3b) for injecting secondary fuel into the primary fuel chamber (4). The arrangement allows mixing of secondary fuel with the primary fuel within the primary fuel chamber (4) prior to injecting fuels through the nozzle (5). An internal combustion engine and a method of injecting fuel are also concerned.

Description

[0001] AN INJECTOR DEVICE, AN INTERNAL COMBUSTION ENGINE AND A METHOD OF INJECTING FUEL

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to fuel injector devices, and more particularly to injector devices for direct injection of fuel into a combustion chamber of an internal combustion engine. The present disclosure further concerns an internal combustion engine and a method for injecting fuel into a combustion chamber of an internal combustion engine.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] In attempt to reduce the environmental impact of emission from internal combustion engines, especially related to large compression ignited engines, there has been an emphasis on studying the use of alternative fuels, such as methanol-based fuels and ammonia-based fuels. Use of such alternative fuels have been discovered to entrail certain challenges. Firstly, the energy content and combustion characteristics of such alternative fuels differ from those of more traditional fuels, such as diesel fuels, requiring changes in the ignition and combustion process. Another challenge relates to the weaker lubrication characteristics of such alternative fuels, resulting in increased wear of friction surfaces between moving components within the fuel system.

[0006] Attempts to alleviate these challenges have been made by using conventional fuels together with alternative fuels. The addition of a conventional fuel portion is considered to act as ignition promoter, i.e., to help initiate compression ignition due to better ignition properties, in addition to improving control over the combustion process by helping maintain the necessary temperature and pressure behaviour for efficient combustion of the alternative fuel. Conventional fuels typically allow easier control over the phasing and rate of combustion, influencing the overall performance and emissions.

[0007] One approach has been made to inject these fuels separately using separate injectors. While allowing great control over the injection, this results in a relatively complex arrangement, which often is not suitable for retrofitting purposes or simply requires too much space to be installed on a cylinder head. Moreover, the generally weak lubrication properties of alternative fuels require additional measures to ensure trouble-free operation.

[0008] Another approach has been preparing a mixture of the fuels and then using a single injector for injecting the mixture. As such alternative fuels and traditional fuels are chemically immiscible, additional chemical emulsifiers and / or mixing arrangements have been used to achieve a mixture of a sufficiently long life. The use of emulsifiers, in turn, increases costs and poses further challenges in regards of emissions, and the control of the combustion and ignition processes.

[0009] BRIEF DESCRIPTION OF THE DISCLOSURE

[0010] An object of the present disclosure is to provide an injector device, which allows mixing of otherwise immiscible fuels. It is a further object of the present disclosure to provide an internal combustion engine equipped with such an injector, and a method of injecting fuel into a combustion chamber of an internal combustion engine.

[0011] The objects of the disclosure are achieved by the injector device, internal combustion engine, and method which are characterized by what is stated in the independent claims. The preferred embodiments of the disclosure are disclosed in the dependent claims.

[0012] The disclosure is based in the idea of mixing a primary fuel and secondary fuel within the injector device immediately before being injected into the combustion chamber, on an on- demand -basis. Notably, secondary fuel is injected into a primary fuel chamber of the injector device from an internal passage arranged within a needle, which needle is used to selectively open or interrupt flow from the primary fuel chamber to the nozzle of the injector device.

[0013] Consequently, as the emulsion of the primary and secondary fuel is produced immediately preceding injection into a combustion chamber, the long-term stability of the emulsion is not of concern. The present disclosure provides for an injector device allowing such mixing of the primary and secondary fuels, while having a relatively simple mechanical construction, and simultaneously addressing concerns related to internal lubrication of the injector device, thereby contributing to improved reliability of the injector device.

[0014] According to a first aspect of the present disclosure, an injector device for injecting liquid fuels into a combustion chamber of an internal combustion engine is provided. The injector device comprises an injector body defining an internal space and an injector needle received within the internal space.

[0015] The injector further comprises a primary fuel chamber delimited between an outside of the injector needle and the internal space. Notably, the primary fuel chamber is connectable in fluid communication with a primary fuel supply. For example, the injector body may comprise one or more suitable ducts for coupling the primary fuel supply to the primary fuel chamber. The injector further comprises a nozzle arranged at a distal end of the injector body. The nozzle, in turn, comprises a plurality of nozzle orifices extending between an inside of the nozzle and an outside of the nozzle. A needle seat is arranged between the primary fuel chamber and the inside of the nozzle. Suitably, the needle seat is formed on the inner surface of injector body. Moreover, the injector needle extends into the primary fuel chamber, such that, in a closed position, the needle is seated against the needle seat, thereby closing fluid communication between the primary fuel chamber and the nozzle via the needle seat. Correspondingly, in an open position, the needle is spaced apart from the needle seat, thereby allowing fluid communication between the primary fuel chamber and the nozzle via the needle seat, thereby allowing selectively injecting primary fuel through the nozzle.

[0016] Suitably, the injector device may comprise, or be associated to an actuator configured to selectively drive the needle between the open and closed positions. Examples of such actuators include electro-mechanical actuators (e.g., solenoid actuators), hydraulic actuators, pneumatic actuators, and mechanical cam drive arrangements coupled e.g., to a cam shaft of an associated engine.

[0017] Notably, the needle comprises an internal, secondary fuel passage extending longitudinally along the needle. The needle further comprises, at a portion of the needle residing in the primary fuel chamber, one or more needle orifices extending between the internal secondary fuel passage and an outside of the needle. This enables injecting secondary fuel into the primary fuel chamber via the secondary fuel passage internal to the needle.

[0018] The above arrangement allows mixing of the secondary fuel with the primary fuel within the primary fuel chamber prior to injecting fuels through the nozzle.

[0019] As the mixing of the two fuels is done in close vicinity to the injection point (i.e., nozzle) just before fuel enters into the combustion chamber, there is no time for the two fuels to separate prior to the combustion.

[0020] In an embodiment according to the first aspect of the present disclosure, the injector device further comprises a secondary fuel chamber connectable in fluid communication with a secondary fuel supply. For example, the injector body may comprise one or more suitable ducts for coupling the secondary fuel chamber to the secondary fuel supply. Suitably, the secondary fuel chamber may be delimited between the outside of the injector needle and the internal space of the injector body. Preferably, but not necessarily, the secondary fuel chamber annularly surrounds the needle.

[0021] The needle further comprises one or more secondary fuel inlet ducts extending between the secondary fuel passage and an outside of the needle. Particularly, the secondary fuel inlet duct is arranged such that, in the open position, the secondary fuel inlet duct opens to the secondary fuel chamber, thereby allowing fluid communication between the secondary fuel chamber and the secondary fuel passage via secondary fuel inlet duct. Correspondingly, in the closed position, the secondary fuel inlet duct closes from the secondary fuel chamber, thereby interrupting fluid communication between the secondary fuel chamber and the secondary fuel passage via secondary fuel inlet duct. For example, in the closed position, an external end of the secondary fuel inlet duct may be covered by an internal wall of the inner space.

[0022] Such an arrangement allows selectively injecting secondary fuel through the needle orifice, thereby providing for greater control in injecting the secondary fuel.

[0023] In an embodiment according to the first aspect of the present disclosure, the injector device further comprises a sealing chamber delimited between the outside of the injector needle and the internal space of the injector body. Preferably, but not necessarily, the sealing chamber annularly surrounds the needle.

[0024] A purpose of the sealing chamber is to prevent leaking of the primary fuel form the primary fuel chamber into an annular gap between the needle and injector body, notably a part thereof supporting the needle. This can be achieved with the provision of a sealing chamber to which secondary fuel or lubricant is provided at a supply pressure greater than that of the primary fuel.

[0025] Another purpose of such a sealing chamber is to prevent seizing of the needle by providing lubrication based on the properties of the secondary fuel or lubricant. This is achieved by allowing the secondary fuel, typically a diesel fuel like LFO, or the lubricant to penetrate from the sealing chamber into the annular gap between the needle and the injector body, so as to form a lubricating film to keep the needle and the part of the injector body supporting the needle lubricated and sealed in the temperatures and pressures experienced by the injector device. The secondary fuel or the lubricant in the clearance between the needle and its bore provides sealing, lubrication as well as thermal balancing of the components and a predetermined small amount of fuel flow around the needle ensures trouble free operation of the needle.

[0026] Moreover, the sealing chamber can be provided separate from the secondary fuel chamber, in which case the sealing chamber may be connectable in fluid communication with the secondary fuel supply or a lubricant supply. Alternatively, the secondary fuel chamber may constitute the sealing chamber, in which case the sealing chamber is connectable in fluid communication with the secondary fuel supply. Yet another alternative is to provide the sealing chamber as a separate chamber in connection to the secondary fuel chamber in which case the sealing chamber is connectable in fluid communication with the secondary fuel supply either directly or via the secondary fuel chamber.

[0027] In an embodiment according to the first aspect of the present disclosure, the primary fuel chamber comprises a receiving portion and a discharge portion. In such an arrangement, the primary fuel chamber is connectable in fluid communication with the primary fuel supply via the receiving portion and fluid flow from the primary fuel chamber to the nozzle is arranged to run, in the open position, via the discharge portion. Moreover, a neck is arranged between the receiving portion and the discharge portion. That is, a cross- sectional area of the primary fuel chamber is smaller at the neck than at the receiving or discharge portions, respectively. The injector body may then exhibit an increased material thickness at the neck, thereby achieving improved structural strength.

[0028] Preferably, but not necessarily, the neck is arranged to deflect fluid flow from the receiving portion to the discharge portion towards the needle.

[0029] Preferably, but not necessarily, the needle orifices are arranged at the discharge portion.

[0030] In an embodiment according to the first aspect of the present disclosure, the injector body defines an additional internal space and an additional injector needle received within the additional internal space.

[0031] In such an arrangement the injector device further comprises an additional fuel chamber delimited between an outside of the additional injector needle and the additional internal space. Notably, the additional fuel chamber is connectable in fluid communication with the secondary fuel supply. The injector device may further comprise an additional nozzle arranged at a distal end of the injector body. The additional nozzle, in turn, comprises a plurality of additional nozzle orifices extending between an inside of the additional nozzle and an outside of the additional nozzle.

[0032] An additional needle seat may then be arranged between the additional fuel chamber and the inside of the additional nozzle. Moreover, the additional injector needle extends into the additional fuel chamber, such that in a closed position of the additional injector needle, the additional needle is seated against the additional needle seat, thereby closing fluid communication between the additional fuel chamber and the additional nozzle via the additional needle seat. Correspondingly, in an open position of the additional injector needle, the additional needle is spaced apart from the additional needle seat, thereby allowing fluid communication between the additional fuel chamber and the additional nozzle via the additional needle seat, thereby allowing selectively injecting secondary fuel through the additional nozzle. Preferably, but not necessarily, the additional needle seat is formed on the inner surface of the injector body, i.e., on internal wall of the additional internal space.

[0033] Suitably, the injector device may comprise, or be associated to an additional actuator configured to selectively drive the additional needle between the open and closed positions. Examples of such additional actuators include electro-mechanical actuators (e.g., solenoid actuators), hydraulic actuators, pneumatic actuators, and mechanical cam drive arrangements coupled, e.g., to a cam shaft of an associated engine.

[0034] It should be noted that the first aspect of the present disclosure encompasses any combination of two or embodiments, or variants thereof, as discussed above.

[0035] According to a second aspect of the present disclosure, an internal combustion engine, comprising a combustion chamber, is provided. Notably, the internal combustion engine further comprises an injector device according to the first aspect of the present disclosure, as discussed above. Moreover, the injector device is configured to inject fuel into the combustion chamber.

[0036] According to a third aspect of the present disclosure, a method of injecting fuel into a combustion chamber of an internal combustion engine is provided. Particularly, fuel is injected into the combustion chamber using the injector device according to first aspect of the present disclosure, as discussed above.

[0037] Moreover, primary fuel is supplied at a primary fuel pressure, whereas secondary fuel is supplied to at a secondary fuel pressure. Notably, the secondary fuel pressure is higher than the primary fuel pressure. It has been discovered that advantages of the present disclosure, as discussed above, can be achieved even with a relatively small pressure difference, such as 10 bar. Preferably, the pressure difference may be at least 100 bar, and more preferably at least 200 bar. For example, methanol-based or ammonia-based or alcohol-based liquid fuels can be used as the primary fuel at supply pressure ranging from 1500 - 1800 bar, whereas LFO or diesel fuel can be used as the secondary fuel at a supply pressure ranging from 2000 - 2200 bar.

[0038] BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the following the disclosure will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which:

[0040] Fig. 1 illustrates a sectional view of an injector device according to an embodiment of the present disclosure, as shown in an open position of a needle; Fig. 1 a illustrates a detailed view of Fig. 1 , in which a portion of the needle, a primary fuel chamber and a nozzle is shown;

[0041] Fig. 1 b illustrates a detailed view of Fig. 1 , in which a portion of the needle and a secondary fuel chamber is shown;

[0042] Fig. 2 illustrates a sectional view of the injector device of Fig. 1 , as shown in a closed position of the needle

[0043] Fig. 2a illustrates a detailed view of Fig. 2, in which a portion of the needle, the primary fuel chamber and the nozzle is shown;

[0044] Fig. 2b illustrates a detailed view of Fig. 2, in which a portion of the needle and the secondary fuel chamber is shown, and

[0045] Fig. 3 illustrates a sectional view of an injector device according to an embodiment of the present disclosure, equipped with an additional needle and an additional nozzle, and having an alternative secondary fuel chamber configuration.

[0046] Fig. 3a illustrates a detailed view of Fig. 3, in which a portion of the needle and the secondary fuel chamber is shown, and

[0047] DETAILED DESCRIPTION OF THE DISCLOSURE

[0048] Fig. 1 illustrates a sectional view of an injector device 1 according to an embodiment of the present disclosure. Notably, the sectional view of Fig. 1 illustrates the injector body 2 of the injector device 1 defining an internal space 2a, in which an injector needle 3 is received.

[0049] A nozzle 5 is arranged at a distal end of the injector device 1 . As shown in in more detail in Fig. 1 a, the nozzle 5 is equipped with a plurality of nozzle orifices 5b, extending between an inside 5a and an outside of the nozzle 5, for injecting fuel from the injector device 1. A primary fuel chamber 4 is also shown being delimited between an outside of the injector needle 3 and the internal space 2a of the injector body 2. A needle seat 6 can be seen arranged between the primary fuel chamber 4 and the inside of the nozzle 5a, so as to connect the primary fuel chamber 4 to the nozzle 5.

[0050] Fig. 1 a further shows the needle 3 being spaced apart from the needle seat 6, i.e., in the open position of the needle 3, in which fuel flow from the primary fuel chamber 4 to the nozzle 5 is not prevented by the needle 3. Correspondingly, Fig. 2a clearly depicts the needle 3 being seated against the needle seat 6. Moreover, Fig. 1 clearly shows the needle 3 being provided with an internal, secondary fuel passage 3a extending longitudinally along the needle. As shown in more detail in Fig. 1a, the needle 3 is also equipped with needle orifices 3b extending between the internal secondary fuel passage 3a and an outside of the needle 3. As the needle orifices 3b are provided at a portion of the needle 3 residing in the primary fuel chamber 4, injecting secondary fuel into the primary fuel chamber 4 is allowed from the internal secondary fuel passage 3a.

[0051] As depicted in Fig. 1 b, the needle 3 is further equipped with secondary fuel inlet ducts 3c, which extend between the secondary fuel passage and an outside of the needle for feeding the internal secondary fuel passage 3a with secondary fuel from the secondary fuel chamber 7. Notably, the secondary fuel chamber 7 is delimited between the outside of the injector needle 3 and the internal space 2a of the injector body.

[0052] During operation, in the open position of the valve 3, as shown in Fig. 1 , primary fuel provided at a pressure to the primary fuel chamber 4 flows via the needle seat 6 to the inside 5a of the nozzle 5 and further out through the nozzle orifices 5b. At the same time, secondary fuel provided to the secondary fuel chamber 7 at a relatively higher pressure flows via the secondary inlet ducts 3c into the secondary fuel passage 3a, and then further into the primary fuel chamber 4 through needle orifices 3b. As the secondary fuel is introduced into the primary fuel chamber as jets of a relatively higher pressure, the velocity differential of the primary and secondary fuels achieves high-shear mixing of the two fuels. As a result, a homogenous emulsion of the primary fuel and the secondary fuel created within the primary fuel chamber 4, and subsequently injected through the nozzle orifices 5a.

[0053] When fuel injection is to be interrupted, the needle 3 is positioned in the closed position, as illustrated in Fig. 2, Fig. 2a and Fig. 2b. Notably, in the closed position, the needle 3 is seated against the needle seat 6, as clearly shown in Fig. 2a, thereby preventing flow from the primary fuel chamber 4 to the nozzle 5. Additionally, in the closed position of the needle 3, the secondary fuel inlet ducts 3c are positioned out of the secondary fuel chamber 7, as depicted in Fig. 2b, thereby preventing flow of the secondary fuel into the internal secondary fuel passage 3a and further into the primary fuel chamber 4. Notably, in the closed position, an external end of the secondary fuel inlet duct 3c is covered by an internal wall of the inner space 2a.

[0054] As shown in both Fig. 1 and Fig. 2, the secondary fuel chamber 7 also constitutes a sealing chamber 8 delimited between the outside of the injector needle 3 and the internal space 2a of the injector body 2. Secondary fuel is provided also to the sealing chamber 8 at the relatively higher pressure, thereby allowing secondary fuel to penetrate the annular gap between the needle 3 and the portion of internal space 2a supporting the needle 3. This both provides a lubricating film around the needle 3 and prevents primary fuel from seeping into the annular gap and washing the lubrication film. The pressure difference between the secondary fuel and the primary fuel is high enough to deliver enough primary fuel into the clearance between the needle 3 and the portion of the internal space 2a supporting the needle 3 to keep the needle 3 and said portion of the internal space 2a lubricated and sealed in the temperatures and pressures experienced by the injector device 1 .

[0055] Best illustrated in Figs 1 a and 2a, the primary fuel chamber 4 has a receiving portion 4a, and a discharge portion 4b. Notably, primary fuel is introduced into the primary fuel chamber 4, at the receiving portion 4a, and fuel flow from the primary fuel chamber 4 to the nozzle 5 is arranged to run, in the open position, via the discharge portion 4b. Moreover, a neck 4c is arranged between the receiving portion 4a and the discharge portion 4b. Notably, a cross-sectional area of the primary fuel chamber 4 is smaller at the neck 4c than at the receiving portion 4a or discharge portion 4b. The injector body 2a consequently exhibits an increased material thickness at the neck 4c, thereby achieving improved structural strength. The neck 4c is further arranged to deflect fluid flow from the receiving portion 4a to the receiving portion 4b towards the needle 3.

[0056] Fig. 3, in turn illustrates an injector device 1 according to another embodiment of the present disclosure. Most notably, in comparison to the injector device of Figs. 1 and 2, the injector device of Fig. 3 is equipped with an additional injector needle 9, depicted with a dashed line, received within an additional internal space 2c of the injector body 2. In a similar manner, an additional nozzle 11 is arranged at a longitudinal end of the injector body 2, next to the injector nozzle 5. Also, the additional nozzle 11 has additional nozzle orifices 11 b extending between an inside 11 a and an outside of the additional nozzle 11 .

[0057] Moreover, an additional fuel chamber 10 is delimited between the outside of the additional injector needle 9 and the additional internal space 2b. An additional needle seat 12 is arranged between the additional fuel chamber 10 and the inside 11 a of the additional nozzle 11 .

[0058] In the open position of the additional injector needle 9, it is spaced apart from the additional needle seat 12. This allows secondary fuel provided to the additional fuel chamber 10 to flow via the additional needle seat 12 to the inside 11 a of the additional nozzle 11 , and further to be injected through the additional nozzle orifices 11 b. Correspondingly, in the closed position of the additional injector needle 9 (as illustrated in Fig. 3), the additional injector needle 9 is seated against the additional needle seat 12. This closes fluid communication between the additional fuel chamber 10 and the additional nozzle 11 via the additional needle seat 12, thereby interrupting injection of secondary fuel via the additional nozzle 11 .

[0059] Furthermore, in the embodiment of Fig. 3, the configuration of the secondary fuel chamber 7 differs from that of the embodiment of Figs. 1 and 2. Although similarly delimited between the outside of the injector needle 3 and the internal space 2a of the injector body, the secondary fuel chamber 7 is provided separately from the sealing chamber 8. Particularly, the sealing chamber 8 is positioned along the needle 3 between the secondary fuel chamber 7 and the primary fuel chamber 4, although the sealing chamber is otherwise provided in a similar manner as in the embodiment of Figs. 1 and 2.

[0060] Fig. 3 illustrates also the needle 3 in the closed position thereof. That is, as better illustrated in Fig. 3a, the secondary fuel inlet ducts 3c are positioned out of the secondary fuel chamber 7, thereby preventing flow of the secondary fuel into the internal secondary fuel passage 3a and further into the primary fuel chamber 4. Notably, in the closed position, an external end of the secondary fuel inlet duct 3c is covered by an internal wall of the inner space 2a. In the arrangement of Fig. 3, opening the needle (i.e., lifting upwards) moves the secondary fuel inlet ducts 3c into the secondary fuel chamber 7. This allows flow of the secondary fuel into the internal secondary fuel passage 3a and further into the primary fuel chamber 4.

[0061] LIST OF REFERENCE NUMERALS

[0062] 1 injector device

[0063] 2 injector body

[0064] 2a internal space

[0065] 2b additional internal space

[0066] 3 injector needle

[0067] 3a secondary fuel passage

[0068] 3b needle orifice

[0069] 3c secondary fuel inlet duct

[0070] 4 primary fuel chamber

[0071] 4a receiving portion of primary fuel chamber

[0072] 4b discharge portion of primary fuel chamber 4c neck

[0073] 5 nozzle

[0074] 5a inside of nozzle

[0075] 5b nozzle orifice

[0076] 6 needle seat

[0077] 7 secondary fuel chamber

[0078] 8 sealing chamber

[0079] 9 additional injector needle

[0080] 10 additional fuel chamber

[0081] 11 additional nozzle

[0082] 11 a inside of additional nozzle

[0083] 11 b additional nozzle orifice

[0084] 12 additional needle seat

Claims

CLAIMS1 . An injector device (1 ) for injecting liquid fuels into a combustion chamber of an internal combustion engine, the injector device comprising: an injector body (2) defining an internal space (2a); an injector needle (3) received within the internal space (2a), a primary fuel chamber (4) delimited between an outside of the injector needle (3) and the internal space (2a), said primary fuel chamber (4) being connectable in fluid communication with a primary fuel supply; a nozzle (5) arranged at a distal end of the injector body (2), said nozzle (5) comprising a plurality of nozzle orifices (5b) extending between an inside (5a) of the nozzle and an outside of the nozzle (5); a needle seat (6) arranged between the primary fuel chamber (4) and the inside of the nozzle (5a), wherein the injector needle (3) extends into the primary fuel chamber (4), such that: in a closed position, the needle (4) is seated against the needle seat (6), thereby closing fluid communication between the primary fuel chamber (4) and the nozzle (5) via the needle seat (6), and in an open position, the needle (3) is spaced apart from the needle seat (6), thereby allowing fluid communication between the primary fuel chamber (4) and the nozzle (5) via the needle seat (6), thereby allowing selectively injecting primary fuel through the nozzle (5), characterized in that the needle (3) comprises:- an internal, secondary fuel passage (3a) extending longitudinally along the needle (3), and at a portion of the needle (3) residing in the primary fuel chamber (4), one or more needle orifices (3b) extending between the internal secondary fuel passage (3a) and an outside of the needle (3), for injecting secondary fuel into the primary fuel chamber (4), thereby allowing mixing of the secondary fuel with the primary fuel within the primary fuel chamber (4) prior to injecting fuels through the nozzle (5).

2. The injector device (1 ) according to claim 1 , characterized by comprising a secondary fuel chamber (7) connectable in fluid communication with a secondary fuel supply,wherein the needle (3) further comprises one or more secondary fuel inlet ducts (3c) extending between the secondary fuel passage (3a) and an outside of the needle (3), and wherein the secondary fuel inlet duct (3c) is arranged such that:- in the open position, the secondary fuel inlet duct (3c) opens to the secondary fuel chamber (7), thereby allowing fluid communication between the secondary fuel chamber (7) and the secondary fuel passage (3a) via secondary fuel inlet duct (3c),- in the closed position, the secondary fuel inlet duct (3c) closes from the secondary fuel chamber (7), thereby interrupting fluid communication between the secondary fuel chamber (7) and the secondary fuel passage (3a) via secondary fuel inlet duct (3c), thereby allowing selectively injecting secondary fuel through the needle orifice (3b).

3. The injector device (1 ) according to claim 2, characterized in that the secondary fuel chamber (7) is delimited between the outside of the injector needle (3) and the internal space (2a) of the injector body (2)4. The injector device (1 ) according to claim 2 or 3, characterized in that, in the closed position, an external end of the secondary fuel inlet duct (3c) is covered by an internal wall of the inner space (2a).

5. The injector device (1 ) according to any of the preceding claims 1 -4, characterized by comprising a sealing chamber (8) delimited between the outside of the injector needle (3) and the internal space (2a) of the injector body (2).

6. The injector device (1 ) according to claim 5, characterized in that either the secondary fuel chamber (7) and the sealing chamber (8) are separate, wherein the sealing chamber (8) being connectable in fluid communication with the secondary fuel supply or a lubricant supply, or- the secondary fuel chamber (7) constitutes the sealing chamber (8), wherein the sealing chamber (8) being connectable in fluid communication with the secondary fuel supply.

7. The injector device according to any of the preceding claims 1 -6, characterized in that the primary fuel chamber (4) comprises:a receiving portion (4a), wherein the primary fuel chamber (4) is connectable in fluid communication with the primary fuel supply via the receiving portion (4a); a discharge portion (4b), wherein fluid flow from the primary fuel chamber (4) to the nozzle (5) is arranged to run, in the open position, via the discharge portion (4b), a neck (4c) arranged between the receiving portion (4a) and the discharge portion (4b), wherein a cross-sectional area of the primary fuel chamber (4) is smaller at the neck (4c) than at the receiving portion (4a) or the discharge portion (4b).

8. The injector device (1 ) according to any of the preceding claims 1 -7, characterized in that the injector body (2) defines an additional internal space (2b), the injector device(I ) further comprising: an additional injector needle (9) received within the additional internal space (2b); an additional fuel chamber (10) delimited between an outside of the additional injector needle (9) and the additional internal space (2b) said additional fuel chamber (10) being connectable in fluid communication with the secondary fuel supply; an additional nozzle (11 ) arranged at a distal end of the injector body (2), said nozzle(I I ) comprising a plurality of additional nozzle orifices (11 b) extending between an inside (11 a) of the additional nozzle (11) and an outside of the additional nozzle (11); an additional needle seat (12) arranged between the additional fuel chamber (10) and the inside (11 a) of the additional nozzle (11), wherein the additional injector needle (9) extends into the additional fuel chamber (10), such that: in the closed position of the additional injector needle (9), the additional needle (9) is seated against the additional needle seat (12), thereby closing fluid communication between the additional fuel chamber (10) and the additional nozzle (11 ) via the additional needle seat (12), and in the open position of the additional injector needle (9), the additional needle (9) is spaced apart from the additional needle seat (12), thereby allowing fluid communication between the additional fuel chamber (10) and the additional nozzle (11 ) via the additional needle seat (12), thereby allowing selectively injecting secondary fuel through the additional nozzle (11 ).

9. An internal combustion engine comprising a combustion chamber, characterized by further comprising an injector device (1 ) according to any of the preceding claims 1 -8, wherein said injector device (1 ) being configured to inject fuel into the combustion chamber.

10. A method of injecting fuel into a combustion chamber of an internal combustion engine, characterized in that fuel is injected into the combustion chamber using the injector device according to any of the preceding claims 1 -9, wherein primary fuel is supplied at a primary fuel pressure, wherein secondary fuel is supplied to at a secondary fuel pressure, and wherein the secondary fuel pressure is higher than the primary fuel pressure.

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