Fuel injector

Patent metadata

Field	Value
Publication number	US-2022298999-A1
Application number	US-202017627955-A
Country	US
Kind code	A1
Filing date	Jul 8, 2020
Priority date	Jul 17, 2019
Publication date	Sep 22, 2022
Grant date	—

Abstract

The invention relates to a fuel injector (10), comprising a nozzle body (12) in which a blind hole (19) is formed, wherein at least one injection opening (14) leads off same, comprising a nozzle needle (25; 25a to 25c) that is reciprocatingly movable along a longitudinal axis (18), wherein the nozzle needle (25; 25a-25c) has a valve seat (29) which forms a sealing seat (26) with a seating surface (21) in the nozzle body (12) in a lowered position of the nozzle needle (25; 25a-25c), and comprising at least one borehole (34; 34a-34c) in the nozzle needle (25; 25a-25c), wherein at least some portions of a borehole inlet (36) of the at least one borehole (34; 34a-34c) are located in the region of the seating surface (21) when the sealing seat (26) is formed, and a borehole outlet (40) of the at least one borehole (34; 34a-34c) is located below the valve seat (29) of the nozzle needle (25; 25a-25c) in the direction of the longitudinal axis (18).

First claim

1 . A fuel injector ( 10 ) comprising
a nozzle body ( 12 ), in which a blind hole ( 19 ) is formed, wherein at least one injection opening ( 14 ) leads off from the blind hole, a nozzle needle ( 25 ; 25 a to 25 c ), configured to be moved in a reciprocating manner along a longitudinal axis ( 18 ), wherein the nozzle needle ( 25 ; 25 a to 25 c ) has a valve seat surface ( 29 ), which forms a sealing seat ( 26 ) with a seat surface ( 21 ) in the nozzle body ( 12 ) in a lowered position of the nozzle needle ( 25 ; 25 a to 25 c ), and at least one bore ( 34 ; 34 a to 34 c ) in the nozzle needle ( 25 ; 25 a to 25 c ), wherein at least some portions of a bore inlet ( 36 ) of the at least one bore ( 34 ; 34 a to 34 c ) are arranged in a region of the seat surface ( 21 ) when the sealing seat ( 26 ) is formed, and a bore outlet of the at least one bore ( 34 ; 34 a to 34 c ) is arranged below the valve seat surface ( 29 ) of the nozzle needle ( 25 ; 25 a to 25 c ) in a direction of the longitudinal axis ( 18 ), wherein the nozzle needle ( 25 ; 25 a to 25 c ) has, from a region of the valve seat surface ( 29 ) to an end face ( 30 ) facing the blind hole ( 19 ), a conical or frustoconical needle tip ( 28 ) with a constant angle (γ), wherein the bore inlet ( 36 ) emerges in the region of the valve seat surface ( 29 ), and wherein the blind hole ( 19 ) has, in a region of the sealing seat ( 26 ), a section with a first angle (β 1 ) with respect to the longitudinal axis ( 18 ), which is adjoined in the direction of a blind hole bottom ( 23 ) by a section (β 2 ) with a second angle (β 2 ), wherein the second angle (β 2 ) is smaller than the first angle (β 1 ) in relation to the longitudinal axis ( 18 ).

2 . The fuel injector as claimed in claim 1 , wherein the at least one bore ( 34 ) is a rectilinear bore ( 34 ; 34 a ) and is arranged at an oblique angle (Δ) with respect to the longitudinal axis ( 18 ).

3 . The fuel injector as claimed in claim 2 , wherein the oblique angle (Δ) of the at least one bore ( 34 ) corresponds to an oblique angle (α) of the at least one injection opening ( 14 ) in the nozzle body ( 12 ).

4 . The fuel injector as claimed in claim 2 , wherein the bore outlet ( 40 )-of the at least one bore ( 34 ) is arranged at a height of the injection opening ( 14 ) or between the injection opening ( 14 ) and the blind hole bottom ( 23 ) when the nozzle needle ( 25 ) is in the lowered position.

5 . The fuel injector as claimed in claim 2 , wherein the nozzle needle ( 25 ) is arranged in a rotationally fixed manner in relation to the direction of the longitudinal axis ( 18 ), and wherein the bore outlet of the at least one bore ( 34 ) is located at a height of the at least one injection opening ( 14 ) in the nozzle body ( 12 ) on a side facing the blind hole ( 19 ) when the nozzle needle ( 25 ) is lowered.

6 . The fuel injector as claimed in claim 1 , wherein the bore outlet of the at least one bore ( 34 a; 34 b; 34 c ) emerges in a region of an end face ( 30 ) of the needle tip ( 28 ) which faces the blind hole bottom ( 23 ).

7 . The fuel injector as claimed in claim 2 , wherein the at least one bore ( 34 ) does not intersect the longitudinal axis ( 18 ).

8 . The fuel injector as claimed in claim 6 , wherein the at least one bore ( 34 b; 34 c ) has a plurality of bore sections ( 41 ; 45 ), wherein a first bore section ( 41 ) of the plurality of bore sections faces the end face ( 30 ) of the needle tip ( 28 ) and extends concentrically with respect to the longitudinal axis ( 18 ).

9 . The fuel injector as claimed in claim 8 , wherein, on a side of the needle tip ( 28 ) which faces away from the end face ( 30 ), the first bore section ( 41 ) opens into a transverse bore ( 48 ) as a second bore section ( 45 ) of the plurality of bore sections, wherein the second bore section extends perpendicularly to the longitudinal axis ( 18 ) and passes through the nozzle needle ( 25 c ).

10 . The fuel injector as claimed in claim 8 , wherein, on a side which faces away from the end face ( 30 ) of the needle tip ( 28 ), the first bore section ( 41 ) is connected to at least one bore ( 42 , 43 ) as a second bore section ( 45 ) of the plurality of bore sections, wherein the second bore section is arranged at an oblique angle with respect to the longitudinal axis ( 18 ).

11 . The fuel injector as claimed in claim 6 , wherein the end face ( 30 ) of the needle tip ( 28 ) is arranged on a side of an upper inlet edge ( 51 ) of the injection opening ( 14 ) which faces the blind hole bottom ( 23 ) when the nozzle needle ( 25 b; 25 c ) is partially open, in which case a ratio A Sitz is <1.5×A SI , wherein A Sitz is an annular flow cross section between the nozzle needle and the nozzle body and A SI is the a total area of cross-sectional areas of the injection opening ( 14 ) or injection openings ( 14 ).

12 . The fuel injector as claimed in claim 1 , wherein the bore inlet ( 36 ) of the at least one bore ( 34 ; 34 a to 34 c ) is arranged in a transitional region between the seat surface ( 21 ) and the section ( 22 ) of the nozzle body ( 12 ) when the sealing seat ( 26 ) is formed.

13 . The fuel injector as claimed in claim 1 , wherein a diameter of the at least one bore ( 34 ; 34 a to 34 c ) in the nozzle needle ( 25 ; 25 a to 25 c ) is less than or equal to a diameter of the at least one injection opening ( 14 ).

Assignees

• Bosch Gmbh Robert

Inventors

• Leukart Michael
• Wolf Fabian
• Nicolai Ferdinand
• Lessing Ulrich

Classifications

• F02M61/1886 Primary

  Details of valve seats not covered by groups F02M61/1866 - F02M61/188 · CPC title

• F02M61/1866 Primary

  Valve seats or member ends having multiple cones · CPC title

• F02M61/042 Primary

  The valves being provided with fuel passages · CPC title

• F02M61/1893

  Details of valve member ends not covered by groups F02M61/1866 - F02M61/188 · CPC title

• F02M2200/06

  Fuel-injection apparatus having means for preventing coking, e.g. of fuel injector discharge orifices or valve needles · CPC title