Fuel injector arrangement

Abstract

A fuel injector arrangement for supplying fuel into a cylinder of an internal combustion engine. The fuel injector arrangement includes a fuel injector and a sealing ring which is arranged around the circumference of the fuel injector. The sealing ring is located between a fuel inlet and/or outlet of the fuel injector located nearest to an injector tip of the fuel injector and the injector tip, wherein the sealing ring has an asymmetrical cross section with a narrow end extending towards the injector tip and a wider end extending away from the injector tip. The wider end has a recess therein creating two legs with a space there between.

Claims

1. A fuel injector arrangement for supplying fuel into a cylinder of an internal combustion engine, the fuel injector arrangement comprising a fuel injector and a sealing ring which is arranged around the circumference of the fuel injector, the sealing ring being located between at least or one of: a fuel inlet of the fuel injector located nearest to an injector up of the fuel injector and the injector tip, and an outlet of the fuel injector located nearest to an injector tip of the fuel injector and the injector tip, wherein the fuel injector arrangement is adapted to be positioned in art opening of a housing part so that a gap is formed between a portion of the fuel injector around which the sealing ring is arranged and the housing part, and wherein the sealing ring has an asymmetrical cross section with a narrow end extending towards the injector tip and a wider end extending away from the injector tip wherein the wider end has a recess therein creating two legs with a space therebetween, such that an outer leg of the two legs is moveable from an abutment position, the outer leg of the two legs abutting the housing in the abutment position to seal the gap when the fuel injector arrangement is positioned in the opening in, the housing part, towards an inner leg of the two legs.

2. A fuel injector arrangement according to claim 1, wherein the legs extend in a diverging configuration in a direction from the narrow end towards the wider end.

3. A fuel injector arrangement according to claim 1, wherein a first leg of the legs comprises a substantially straight radially inner surface contacting a radially outer surface of the fuel injector.

4. A fuel injector arrangement according to claim 1, wherein a first leg of the legs has an at, least partly straight extension direction between the narrow end and the wider end.

5. A fuel injector arrangement according to claim 1, Wherein a second leg of the legs comprises a free end configured for radial abutment against a radially inner surface of art injector housing part.

6. A fuel injector arrangement according to claim 1, wherein the second leg of the legs has an at least partly straight extension direction between the narrow end and the wider end.

7. A fuel injector arrangement according to claim 1, Wherein a second leg of the two legs projects from a first end of a first leg of the legs at the narrow end.

8. A fuel injector arrangement according to claim 1, wherein the asymmetrical cross section of the sealing ring is in the shape of a V.

9. A fuel injector arrangement according to claim 1, wherein a second leg of the two legs projects from a position between a first end at the narrow end and a second end at the wider end of a first leg of the legs.

10. A fuel injector arrangement according to claim 1, wherein the sealing ring is in contact with the fuel injector along the complete height of the sealing ring, from the narrow end to the wide end.

11. A fuel injector arrangement according to claim 1, wherein the angle between the legs of the sealing ring lies between 25 and 70 degrees.

12. A fuel injector arrangement according to claim 1, wherein the sealing ring is made of an elastic material.

13. A fuel injector arrangement according to claim 12, wherein the elastic material is chosen from synthetic rubber and thermoplastic elastomers.

14. A fuel injector arrangement according to claim 13, wherein the synthetic rubber is chosen from butadiene rubber, butyl rubber, chlorosulfonated polyethylene, epichlorohydrin, ethylene propylene rubber, fluoroelastomer, nitrile rubber, perfluoroelastoiner, polyacrylate rubber, polychloroprene, polyisoprene, polysulfide rubber, polytertafluoroethylene, sanifluor and silicone rubber.

15. A fuel injector arrangement according to claim 13 wherein the thermoplastic elastomer is chosen from thermoplastic elastomer styrenics, thermoplastic polyolefin, thermoplastic polyurethane, thermoplastic etheresterelastomers copolyesters, thermoplastic polyamide, melt processible rubber and thermoplastic vulcanite.

16. A fuel injector arrangement according to claim 1, wherein the sealing ring has a height of 2 to 5 mm, and a width of 0.25 to 4 mm.

17. A fuel injection system for supplying fuel into a cylinder of an internal combustion engine, wherein the fuel injection system comprises a housing part with an opening configured for receiving a fuel injector arrangement wherein the fuel, injector arrangement according to claim 1 is positioned in the opening.

18. A fuel injection system according to claim 17, wherein the opening comprises a widened portion forming a part of a fuel gallery around the fuel injector and that the sealing ring is positioned around the fuel injector between the fuel gallery and the injector tip.

19. A fuel injection system according to claim 17, comprising a sleeve which receives a portion of the fuel injector in the vicinity of the injector tip and wherein the sleeve is arranged in the opening.

20. An internal combustion engine comprising a fuel injector arrangement according to claim 1.

21. A vehicle comprising an internal combustion engine according to claim 20.

22. A fuel injector arrangement according to claim 1, wherein a surface of the sealing ring defining the recess faces away from the injector tip.

23. A fuel injector arrangement according to claim 1, wherein the fuel injector arrangement is adapted to be positioned in an opening of a housing part so that a gap is formed between a portion of the fuel injector around which the sealing ring is arranged and the housing part and, when the fuel injector arrangement is positioned in the opening in the housing part, the sealing ring seals, the gap between the fuel injector and the housing pact.

24. A fuel injection system according to claim 17, wherein the fuel injector arrangement is positioned in the opening, of a housing part so that a gap is formed between a portion of the fuel injector around which the sealing ring is arranged and the housing part and, when the fuel injector arrangement is positioned in the opening in the housing part, the sealing ring seals the gap between the fuel injector and the housing part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With reference to the appended drawings, below follows a more detailed description of example embodiments of the invention.

(2) FIG. 1 shows a vehicle comprising an internal combustion engine.

(3) FIG. 2 illustrates a fuel injection system according to a first embodiment, in a cross sectional side view, wherein said system comprises a fuel injector arrangement according to a first embodiment and a sealing ring according to a first embodiment.

(4) FIGS. 3-5 shows the sealing ring according to a second, third and fourth embodiment.

DETAILED DESCRIPTION

(5) The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which different embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

(6) FIG. 1 shows a vehicle 40 in the form of a truck, which comprises an internal combustion engine 30, in the form of a diesel engine for propelling the truck. The internal combustion engine 30 comprises a fuel injector system 20, which is shown in FIG. 2. The fuel injector system 20 in turn comprises a fuel injector arrangement 1, which is also shown in FIG. 2.

(7) In FIG. 2, the fuel injector arrangement 1 is shown according to a first embodiment. The fuel injector arrangement 1 comprises a fuel injector 11 and a sealing ring 2 according to a first embodiment. The fuel injector 11 is elongated and comprises an injector casing and an internal fuel system for delivery of fuel to its spray tip 4. The sealing ring 2 is arranged around the circumference of the fuel injector 11, and more specifically in a groove in the injector casing. The sealing ring is located between a fuel inlet and/or outlet 3 of the fuel injector located nearest to the injector tip 4 and the injector tip 4 of the fuel injector. The sealing ring 2 has an asymmetrical cross section with a narrow end 5 extending towards the injector tip 4 of the fuel injector 11 and a wider end 6 extending away from the injector tip 4. In the wider end edge 6 a recess 7 is present thereby creating two legs 8, 9 with a space there between.

(8) The groove has dimensions which substantially correspond to a height and a width of the sealing ring 2. More specifically, the groove has parallel upper and lower inner surfaces.

(9) In FIG. 2, the fuel injector 11 is depicted with only one fuel inlet and/or outlet 3. It is also known that fuel injectors 11 may comprise more than one fuel inlet and/or outlet 3 each of which may have the same function or they can have different functions. For such fuel injectors 11, it is possible to use more than one sealing ring 2 between each of the fuel inlet and/or outlet 3 as long as the sealing ring 2 situated closest to the injector tip 4 is a sealing ring 2 as described herein.

(10) The fuel injection system 20 comprises a housing part 21 with an elongated opening 22 configured for receiving the fuel injector arrangement 1. The fuel injector arrangement 1 is positioned in the opening 22. The fuel injection system 20 is configured and arranged to supply fuel into at least one cylinder of the internal combustion engine 30. When the fuel injector arrangement 1 is positioned in the opening 22 in the housing part 21, the sealing ring 2 is configured to provide a sealing of the gap between the fuel injector 11 and the housing part 21.

(11) A fuel gallery 25 is present in communication with the fuel inlet and/or outlet 3 of the fuel injector 11. More specifically, the fuel inlet and/or outlet 3 of the fuel injector 11 ends in the fuel gallery 25. The fuel gallery 25 forms a fuel channel extending in a crosswise direction in relation to an axial direction of the fuel injector 11 and is preferably configured for distributing fuel to a plurality of the fuel injectors of the engine. The sealing ring 2 is positioned between the fuel gallery 25 and the injector tip 4.

(12) Below the sealing ring 2 in the direction of the fuel injector tip 4, a cavity 24 is formed between the fuel injector 11 and the housing 21. More specifically, a portion of the opening 22 is formed with a wider diameter than an outer diameter of a corresponding part of the injector, which portion forms the cavity.

(13) In the specific embodiment illustrated, an injector sleeve 28 is used in combination with the housing part 21 to hold the fuel injector 11. The sleeve 28 receives a portion of the fuel injector 11 in the vicinity of the injector tip 4. The housing part 21 is provided with cooling channels around the sleeve 28 for cooling thereof. The injector sleeve 28 is placed in the opening 22 of the housing part 21 and a seal 29 is used to provide a tight fit between the housing part 21 and the injector sleeve 28. The seal 29 is positioned in a groove in the sleeve 28 and can be any standard type of seal used for sealing as long as it is compatible with fuel and combustion gases, examples of seals may be an o-ring, a metal seal, a polymeric seal, an elastic seal or combinations thereof. The injector sleeve 28 and the housing part 21 assist in holding and aligning the fuel injector 11 into a correct position. The fuel injector 11 is in direct contact with the injector sleeve 28 at a contact area 23. The contact force in the contact area 23 is assisted by a yoke 26 at an opposite side of the injector in relation to the injector tip 4. The yoke 26 is configured to push the fuel injector 1 towards the housing part 21 and injector sleeve 28 to secure a tight seal in the contact area 23.

(14) In FIG. 2, a cylinder head 27 is depicted with the housing part 21 in combination with the injector sleeve 28. It is also known to have a housing part without an injector sleeve 28, where the housing part extends along the side of the fuel injector 11 all the way from the top of the housing part near the yoke 26 to the fuel injector tip 4. The housing part of the cylinder head 27 will then form a contact area 23 with the fuel injector 11.

(15) Turning now to the design of the seal 2. The legs 8, 9 extend in a diverging configuration in a direction from the narrow end 5 towards the wider end 6. The first leg 9 has a substantially straight radially inner surface 32 contacting a straight radially outer surface of the fuel injector 11 within the groove. In other words, the groove is configured so that the inner surface extends in an axial direction of the injector 11. FIG. 2 shows the seal 2 in a state applied around the injector 11, wherein the complete radially inner surface 32 of the fuel injector 11 contacts the radially outer surface of the fuel injector 11 within the groove.

(16) The first leg 9 has an at least partly substantially straight extension direction between the narrow end 5 and the wider end 6 of the sealing ring 2. More specifically, the first leg 9 has a straight extension direction between the narrow end 5 and the wider end. 6 of the sealing ring 2.

(17) The second leg 8 comprises a free end 31 configured for radial abutment against a radially inner surface of the injector housing part 21. The second leg 8 has an extension direction at an angle in relation to the radially inner surface of the opening 22 of the injector housing part 21. The second leg 8 has an extension direction at an angle in relation to the axial direction of the fuel injector 11. The free end 31 of the second leg 8 will by means of this configuration contact the radially inner surface of the opening 22 along a relatively short axial distance. More specifically, the contact surface of the second leg 8 to the radially inner surface of the opening 22 is much smaller than the contact surface of the first leg 9 to the inner surface of the groove. Further, the second leg 8 has such an extension that its free end 31 is positioned at an axial distance from an upper limitation surface of the groove. More specifically, the free end 31 is positioned closer to an upper limitation surface of the groove than a lower limitation surface of the groove in the axial direction of the fuel injector 11.

(18) The second leg 8 has an at least partly substantially straight extension direction between the narrow end 5 and the wider end 6. The second leg 8 projects from a first end of a first leg 9 of said legs at the narrow end 5. The asymmetrical cross section of the sealing ring 2 is in the basic shape of a V. Further, a lower part of the seal 2 facing towards the injector tip 4 is not acute like in a proper V-shape, but rather flat and abuts a lower surface of the groove along a substantial portion thereof. More specifically, the seal 2 is configured so that it extends along the lower surface of the groove along at least half its radial extension.

(19) The sealing ring has a height 10 and a width 12. The sealing ring 2 is in contact with the fuel injector 1 along the complete height 10 of the sealing ring 2, from the narrow end 5 to the wide end 6.

(20) The sealing ring 2 can be prepared using any type of a wide range of materials considered suitable for use in an environment with fuel and combustion gas. The material used should allow for some flexibility as it will need to allow the combustion gas caught in the cavity 24 between the fuel injector arrangement 1 and the housing 21 to slowly seep past the sealing ring 2 as a micro leakage, as the pressure drops in the fuel gallery 25. An example of a material having some flexibility would be an elastic material, however the skilled worker could envisage a number of such materials such as: a metal sealing ring 2 which has a thin second leg 8 thus allowing for flexibility in this second leg 8, a polymer material which is not considered elastic but nevertheless has some flexible properties, or combinations of these material types.

(21) In FIG. 3, a sealing ring 102 is shown according to a second embodiment where the sealing ring 102 has an asymmetrical cross section with a narrow end 105 extending towards an injector tip 4 of the fuel injector 11 and a wider end 106 extending away from the injector tip 4. In the wider end 106 a recess 107 is present thereby creating two legs 108,109 with a space there between. The depth of the recess 107 can be varied depending on the material used. This can be used to optimize the sealing ring 102 in order to ensure a structure which is rigid enough to withstand the forces acting on the sealing ring 102 and yet still has some flexibility to allow for the micro leakage.

(22) The legs 108,109 extend in a diverging configuration in a direction from the narrow end 105 towards the wider end 106. The first leg 109 has a substantially straight radially inner surface 132 contacting a radially outer surface of the fuel injector 11. The first leg 109 has an at least partly substantially straight extension direction between the narrow end 105 and the wider end 106 of the sealing ring 102.

(23) The second leg 108 comprises a free end 131 configured for radial abutment against a radially inner surface of an injector housing part. The second leg 8 has an at least partly substantially straight extension direction between the narrow end 5 and the wider end 6. The second leg 8 of said two legs projects from a first end of a first leg 9 of said legs at the narrow end 5. The asymmetrical cross section of the sealing ring 2 is in the shape of a V.

(24) The sealing ring has a height 110 and a width 112. The sealing ring 102 is in contact with the fuel injector 1 along the complete height 110 of the sealing ring. 102, from the narrow end 105 to the wide end 106. Between the legs 108,109 of the sealing ring 102 an angle a is formed.

(25) In FIG. 4, a sealing ring 202 is shown according to a third embodiment where the sealing ring 202 has an asymmetrical cross section with a narrow end 205 extending towards an injector tip 4 of the fuel injector 11 and a wider end 206 extending away from the injector tip 4. In the wider end edge 206 a recess 207 is present thereby creating two legs 208,209 with a space there between.

(26) The legs 208,209 extend in a diverging configuration in a direction from the narrow end 205 towards the wider end 206. The first leg 209 has a substantially straight radially inner surface 232 contacting a radially outer surface of the fuel injector 1. The first leg 209 has an at least partly substantially straight extension direction between the narrow end 205 and the wider end 206 of the sealing ring 202.

(27) The second leg 208 comprises a free end 231 configured for radial abutment against a radially inner surface of an injector housing part. The second leg 208 has an at least partly substantially straight extension direction between the narrow end 205 and the wider end 206. The second leg 208 projects from a position between a first end at the narrow end 205 and a second end at the wider end 206 of a first leg 209 of said legs. More specifically, the second leg 208 projects from a position about midway between a first end at the narrow end 205 and a second end at the wider end 206 of a first leg 209.

(28) The sealing ring 202 has a height 210 and a width 212. The sealing ring 202 is in contact with the fuel injector 1 along the complete height 210 of the sealing ring 202, from the narrow end 205 to the wide end 206. Between the legs 208,209 of the sealing ring 202 an angle a is formed.

(29) In FIG. 5, a sealing ring 302 is shown according to a fourth embodiment where the sealing ring 302 has an asymmetrical cross section with, a narrow end 305 extending towards an injector tip 4 of the fuel injector 1 and a wider end 306 extending away from the injector tip 4. In the wider end edge 306 a recess 307 is present thereby creating two legs 308,309 with a space there between.

(30) The legs 308,309 extend in a diverging configuration in a direction from the narrow end 305 towards the wider end 306. The first leg 309 has a substantially straight radially inner surface 332 contacting a radially outer surface of the fuel injector 11. The first leg 309 has an at least partly substantially straight extension direction between the narrow end 305 and the wider end 306 of the sealing ring 2.

(31) The second leg 308 comprises a free end 331 configured for radial abutment against a radially inner surface of an injector housing part. The second leg 308 projects from a first end of a first leg 309 of said legs at the narrow end 305. The legs 8,9 are joined in a slightly curved region.

(32) The sealing ring has a height 310 and a width 312. Between the legs 308,309 of the sealing ring 302 an angle a is formed.

(33) Additionally, variations to the disclosed example embodiments can be understood and effected by the skilled person in practicing the claimed invention, from study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to claim advantages.