A DISTRIBUTOR FUEL RAIL AND A METHOD FOR MANUFACTURING A DISTRIBUTOR FUEL RAIL

Abstract

The present disclosure relates to a diesel distributor fuel rail for a diesel combustion engine with a diesel distributor conduit and a plurality of injector cups in fluid connection with a diesel distributor conduit. In order to make combustion engines having a smaller cylinder capacity more efficient, it is necessary to enhance fuel pressure in the distributor fuel rail. On the other hand the footprint available for the distributor fuel rail has not changed. According to the present disclosure it is thus suggested to provide at least a section of the distributor conduit by a tube made of an austenitic stainless steel comprising, in weight %, C0.080, 8.00Mn10.00 Si1.00, P0.030 S0.030 19.00Cr21.50, 5.50Ni7.50, 0.15N0.40, Mo0.75, Cu0.75, balance Fe and normally occurring impurities.

Claims

1. A distributor fuel rail for a combustion engine with a tubing, wherein at least a section of the tubing is provided by a seamless tube made of an austenitic stainless steel comprising, in weight %, C0.080, 8.00Mn10.00, Si1.00, P0.030, S0.030, 19.00Cr21.50, 5.50Ni7.50, 0.15N0.40, Mo0.75, Cu0.75, balance Fe and normally occurring impurities.

2. The distributor fuel rail according to claim 1, wherein the tube is obtained by a method comprising the steps: providing a melt of an austenitic stainless steel comprising, in weight %, C0.080, 8.00Mn10.00, Si1.00, P0.030, S0.030, 19.00Cr21.50, 5.50Ni7.50, 0.15N0.40, Mo0.75, Cu0.75, balance Fe and normally occurring impurities; extruding a billet from the melt; hot forming of the billet into a tubular hollow; cooling the hollow; and cold forming the hollow into the tube.

3. The distributor fuel rail according to claim 1, wherein the tubing of the distributor fuel rail comprises a distributor conduit, a plurality of injector cups in fluid communication with the distributor conduit and a at least one feeder line in fluid communication with the distributor conduit.

4. The distributor fuel rail according to claim 2, wherein the cold forming is cold pilger milling or cold drawing.

5. The distributor fuel rail according to claim 2, wherein the tube is cold formed by cold pilger milling and the tube after cold pilger milling is cold drawn through a drawing die.

6. The distributor fuel rail according to claim 5, wherein the tube after cold forming is treated by ring autofrettage or ball autofrettage.

7. The distributor fuel rail according to claim 5, wherein the tube after cold pilger milling is annealed at a temperature in a range from 400 C. to 460 C., and wherein during annealing the tube is kept in a controlled atmosphere.

8. The distributor fuel rail according to claim 1, wherein the tube has a wall thickness which is equal to or larger than one quarter of the outer diameter of the tube.

9. A diesel combustion engine comprising the distributor fuel rail according to claim 1.

10. An Otto combustion engine comprising the distributor fuel rail according to claim 1.

11. A vehicle comprising a combustion engine according to claim 10.

12. Use of the distributor fuel rail according to claim 1 for guiding fuel pressurised at 800 bar or more.

13. A method for manufacturing a distributor fuel rail, wherein manufacturing of a tube forming at least part of the distributor fuel rail comprises the steps: providing a melt of an austenitic stainless steel comprising, in weight %, C0.080, 8.00Mn10.00, Si1.00, P0.030, S0.030, 19.00Cr21.50, 5.50Ni7.50, 0.15N0.40, Mo0.75, Cu0.75, balance Fe and normally occurring impurities; extruding a billet from the melt; hot forming the billet into a tubular hollow; cooling the hollow; and cold forming the hollow into the tube.

14. The method according to claim 13, wherein the hollow is cold formed by cold pilger milling and wherein the tube after cold pilger milling is cold drawn through a drawing die.

15. The method according to claim 14, wherein the tube after cold forming is treated by ring autofrettage or ball autofrettage.

16. The distributor fuel rail according to claim 4, wherein the tube after cold forming is treated by ring autofrettage or ball autofrettage.

17. The distributor fuel rail according to claim 4, wherein the tube after cold pilger milling is annealed at a temperature in a range from 400 C. to 460 C., and wherein during annealing the tube is kept in a controlled atmosphere.

18. A vehicle comprising a combustion engine according to claim 9.

19. The method according to claim 13, wherein the tube after cold forming is treated by ring autofrettage or ball autofrettage.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0061] Further advantages, features and applications of the present disclosure will become apparent from the following description of embodiments and the corresponding figures attached. The foregoing as well as the following detailed description of the embodiments will be better understood when read in conjunction with the appended drawings. It should be understood that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown.

[0062] FIG. 1 is a schematic side view of a vehicle having a combustion engine with a fuel distributor rail according to an embodiment of the present disclosure.

[0063] FIG. 2 is a flow chart of a method for manufacturing a part of a distributor fuel rail according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0064] FIG. 1 is a schematic side view of a car 1 having a distributor fuel rail 2 according to an embodiment of the present disclosure attached to a combustion engine 8. In the present embodiment the combustion engine 8 is a diesel engine.

[0065] The distributor fuel rail 2 comprises a fuel distributor conduit 3 formed by a seamless steel tube made of an austenitic stainless steel consisting of, in weight %, C0.080, 8.00Mn10.00, Si1.00, P0.030, S0.030, 19.00Cr21.50, 5.50Ni7.50, 0.15N0.40, Mo0.75, Cu0.75, balance Fe and normally occurring impurities.

[0066] The distributor conduit 3 is located between a fuel pump 4 and injectors 5 accommodated in injector cups 6. The fuel is pumped from a tank 7 by the fuel pump 4 to the injectors 5 under a pressure of 1900 bar.

[0067] FIG. 2 is a flow chart describing a method for forming a hollow into the tube 2 used in the application described with reference to FIG. 1. In a first step 100 a melt of an austenitic stainless steel is provided, wherein the austenitic stainless steel consists of, in weight %, C0.040, 8.00Mn10.00, Si1.00, P0.030, S0.030, 19.00Cr21.50, 5.50Ni7.50, 0.15 N0.40, Mo0.75, Cu0.75, balance Fe and normally occurring impurities.

[0068] After extruding a billet from the melt in a second step 101, the billet is hot rolled into a tubular hollow in step 102. The hollow then gets cooled to room temperature in step 103. In a penultimate step 104 the hollow is cold pilger milled into a tube. In a last step 105, the tube is cold drawn through a drawing dye.

[0069] For purposes of the original disclosure, it is noted that all features become apparent for a person skilled in the art from the present description, the figures and the claims even if they have only been described with reference to particular further features and can be combined either on their own or in arbitrary combinations with other features or groups of features disclosed herein as far as such combinations are not explicitly excluded or technical facts exclude such combinations or make them useless. An extensive, explicit description of each possible combination of features has only been omitted in order to provide a short and readable description.

[0070] While the disclosure has been shown in detail in the figures and the above description, this description is only an example and is not considered to restrict the scope of protection as it is defined by the claims. The disclosure is not restricted to the disclosed embodiments.

[0071] Modifications to the disclosed embodiments are apparent for a person skilled in the art from the drawings, the description and the attached claims. In the claims, the word comprising does not exclude other elements or steps and the undefined article a does not exclude a plurality. The mere fact that some features have been claimed in different claims does not exclude their combination. Reference numbers in the claims are not considered to restrict the scope of protection.

REFERENCE NUMERALS

[0072] 1 car

[0073] 2 distributor fuel rail

[0074] 3 fuel distributor conduit

[0075] 4 fuel pump

[0076] 5 injectors

[0077] 6 injector cups

[0078] 7 tank

[0079] 8 engine

[0080] 100 providing a melt of an austenitic stainless steel

[0081] 101 extruding a billet from the melt

[0082] 102 hot rolling of the billet into a tubular hollow

[0083] 103 cooling step

[0084] 104 cold pilger milling step

[0085] 105 cold drawing step