Fuel line assembly having a fuel line and a fuel injector socket

Abstract

A fuel line assembly includes a fuel line having has an inner surface and an outer surface joined to each other by a fuel line aperture. A fuel injector socket has at one end a fixation saddle which is concave within which the fuel line is received such that the fixation saddle has a concave surface facing toward the fuel line. A fuel injector socket receiving bore extends into another end of the fuel injector socket to receive a fuel injector therewithin. A fuel injector socket aperture extends from the concave surface to the fuel injector socket receiving bore. An alignment tube provides fluid communication between the inner surface and the fuel injector socket receiving bore, wherein a portion of the alignment tube is circumferentially surrounded by the fuel line aperture and wherein another portion of the alignment tube is circumferentially surrounded by the fuel injector socket aperture.

Claims

1. A fuel line assembly which supplies fuel to a fuel injector of a fuel consuming device, said fuel line assembly comprising: a fuel line having a fuel line tubular wall which extends along a fuel line axis and has a fuel line inner surface and a fuel line outer surface such that a fuel line aperture extends from said fuel line outer surface to said fuel line inner surface; a fuel injector socket which is tubular and which extends from a fuel injector socket first end to a fuel injector socket second end, said fuel injector socket having a fuel injector socket fixation saddle which is concave at said fuel injector socket first end within which said fuel line is received such that said fuel injector socket fixation saddle has a concave surface facing toward said fuel line, said fuel injector socket also having a fuel injector socket receiving bore extending thereinto from said fuel injector socket second end which is configured to receive said fuel injector therewithin, said fuel injector socket also having a fuel injector socket aperture extending from said concave surface to said fuel injector socket receiving bore; and an alignment tube extending from an alignment tube first end to an alignment tube second end, said alignment tube having an alignment tube passage extending therethrough from said alignment tube first end to said alignment tube second end, said alignment tube also having an alignment tube outer peripheral surface such that a portion of said alignment tube outer peripheral surface is circumferentially surrounded by said fuel line aperture and such that another portion of said alignment tube outer peripheral surface is circumferentially surrounded by said fuel injector socket aperture such that said alignment tube passage provides fluid communication between said fuel line inner surface and said fuel injector socket receiving bore.

2. The fuel line assembly as in claim 1, wherein said fuel injector socket aperture is stepped such that said fuel injector socket aperture has a fuel injector socket aperture outer portion which is proximal to said concave surface and a fuel injector socket aperture inner portion which is proximal to said fuel injector socket receiving bore such that said fuel injector socket aperture outer portion is larger in diameter than said fuel injector socket aperture inner portion.

3. The fuel line assembly as in claim 2, wherein a fuel injector socket aperture shoulder is formed where said fuel injector socket aperture outer portion meets said fuel injector socket aperture inner portion such that said alignment tube is in contact with said fuel injector socket aperture shoulder.

4. The fuel line assembly as in claim 3, wherein an outer periphery of said alignment tube is stepped such that said alignment tube has an alignment tube first portion which extends from said alignment tube first end toward said alignment tube second end and also includes an alignment tube second portion which extends from said alignment tube first portion to said alignment tube second end wherein said alignment tube first portion is larger in diameter than said alignment tube second portion, thereby forming an alignment tube shoulder where said alignment tube first portion meets said alignment tube first portion.

5. The fuel line assembly as in claim 4, wherein said alignment tube shoulder is in contact with said fuel injector socket aperture shoulder.

6. The fuel line assembly as in claim 4, wherein a portion of said alignment tube first portion is circumferentially surrounded by said fuel line aperture and another portion of said alignment tube first portion is circumferentially surrounded by said fuel injector socket aperture outer portion.

7. The fuel line assembly as in claim 6, wherein said alignment tube second portion is circumferentially surrounded by said fuel injector socket aperture inner portion.

8. The fuel line assembly as in claim 7, wherein said alignment tube second portion is received within said fuel injector socket aperture inner portion in an interference fit.

9. The fuel line assembly as in claim 1, wherein said fuel line assembly further comprises a braze material between said fuel line outer surface and said concave surface such that said braze material fixes said fuel injector socket to said fuel line and such that said braze material prevents leakage between said fuel line outer surface and said concave surface.

10. The fuel line assembly as in claim 9, wherein said braze material circumferentially surrounds said alignment tube.

11. The fuel line assembly as in claim 1, wherein said fuel line aperture is centered about a fuel line aperture axis which is perpendicular to said fuel line axis.

12. The fuel line assembly as in claim 11, wherein said fuel injector socket aperture is centered about a fuel injector socket axis which is coincident with said fuel line aperture axis.

13. The fuel line assembly as in claim 1, wherein said fuel line outer surface is centered about said fuel line axis and is cylindrical in cross section when sectioned perpendicular to said fuel line axis.

14. The fuel line assembly as in claim 1, wherein a wall thickness of said fuel line tubular wall is 2 mm or less.

15. The fuel line assembly as in claim 14, wherein an outside diameter of said fuel line is 10 mm or less.

16. A fuel line assembly which supplies fuel to a fuel injector of a fuel consuming device, said fuel line assembly comprising: a fuel line having a fuel line tubular wall which extends along a fuel line axis and has a fuel line inner surface and a fuel line outer surface such that a fuel line aperture extends from said fuel line outer surface to said fuel line inner surface; a fuel injector socket which is tubular, said fuel injector socket having at one end a fuel injector socket fixation saddle which is concave within which said fuel line is received such that said fuel injector socket fixation saddle has a concave surface facing toward said fuel line, said fuel injector socket also having at another end a fuel injector socket receiving bore extending thereinto which is configured to receive said fuel injector therewithin such that a fuel injector socket aperture extends from said concave surface to said fuel injector socket receiving bore; an alignment tube having an alignment tube passage extending therethrough which provides fluid communication between said fuel line inner surface and said fuel injector socket receiving bore, wherein a portion of said alignment tube is circumferentially surrounded by said fuel line aperture and wherein another portion of said alignment tube is circumferentially surrounded by said fuel injector socket aperture.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) This invention will be further described with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic view of a fuel system in accordance with the present disclosure;

(3) FIG. 2 is an isometric view of a fuel line assembly in accordance with the present disclosure;

(4) FIG. 3 is an exploded isometric view of a portion of FIG. 2;

(5) FIG. 4 is a cross-sectional view of a portion of FIG. 2;

(6) FIG. 5 is another cross-section al view of a portion of FIG. 2, now taken through a cutting plane which is rotated 90 compared to FIG. 4;

(7) FIG. 6 is an enlargement of a portion of FIG. 5;

(8) FIG. 7 is a schematic view of internal workings of a fuel injector of FIG. 2; and

(9) FIG. 8 is an enlargement of a portion of FIG. 7.

DETAILED DESCRIPTION OF INVENTION

(10) Referring initially to FIG. 1, a fuel system 10 is shown in simplified schematic form for supplying fuel to a fuel consuming device, for example an internal combustion engine 12, by way of non-limiting example only, for a motor vehicle (not shown). Fuel system 10 includes a fuel tank 14 for storing a volume of fuel, a low-pressure fuel pump 16 which may be located within fuel tank 14 as shown, a high-pressure fuel pump 17 which receives fuel from low-pressure fuel pump 16, a fuel line assembly 18 attached to internal combustion engine 12 and in fluid communication with high-pressure fuel pump 17, and a plurality of fuel injectors 20 in fluid communication with fuel line assembly 18. In operation, low-pressure fuel pump 16 draws fuel from fuel tank 14 and pumps the fuel to high-pressure fuel pump 17 under relatively low pressure, for example about 500 kPa. High-pressure fuel pump 17, which may be a piston pump operated by a cam of internal combustion engine 12, further pressurizes the fuel and supplies the fuel to fuel line assembly 18 under relatively high pressure, for example, above about 14 MPa and even reaching 35 MPa or higher. Each fuel injector 20 receives fuel from fuel line assembly 18 and injects the fuel into a respective combustion chamber 22 of internal combustion engine 12 for combustion of the fuel within combustion chambers 22.

(11) Referring now to FIGS. 7 and 8, fuel injector 20, the internal workings of which are shown in schematic form, includes a fuel injector body 24 which is configured to be inserted into a fuel injector receiving bore 25 of a cylinder head 26 of internal combustion engine 12 such that a nozzle tip 28 of fuel injector body 24 communicates with combustion chamber 22 and includes one or more nozzle openings 30 therein from which fuel is selectively discharged from fuel injector 20 into combustion chamber 22. The discharge of fuel from nozzle openings 30 is controlled by a valve needle 32 located within fuel injector body 24 where valve needle 32 is selectively seated with a valve seat 34 (valve needle 32 being shown in solid lines in FIG. 8) to stop discharge of fuel through nozzle openings 30 and is selectively unseated with valve seat 34 (valve needle 32 being shown in phantom lines in FIG. 8) to discharge fuel from fuel injector 20 into combustion chamber 22. Movement of valve needle 32 is controlled by an actuator 36, illustrated herein as a solenoid actuator. As embodied herein, actuator 36 includes a wire winding 38, a pole piece 40 which is stationary, an armature 42 which is moveable with valve needle 32, and a return spring 44 which urges valve needle 32 in a direction to be seated with valve seat 34. When wire winding 38 is energized with an electric current, armature 42 is magnetically attracted to pole piece 40, thereby unseating valve needle 32 from valve seat 34. Conversely, when the electric current to wire winding 38 is stopped, the magnetic attraction between armature 42 and pole piece 40 is stopped, thereby allowing return spring 44 to move valve needle 32 to be seated with valve seat 34. While actuator 36 has been illustrated herein as a solenoid actuator, it should be understood that actuator 36 may take other forms, which may be, by way of non-limiting example only, a piezoelectric actuator. Furthermore, while actuator 36 has been illustrated as directly actuating valve needle 32, it should be understood that actuator 36 may be indirect acting such that the actuator may be used to control fuel pressure in a control chamber such that the fuel pressure in the control chamber affects the position of valve needle 32. Fuel injector 20 includes a fuel injector inlet conduit 50 which receives fuel from fuel line assembly 18 for selective injection into combustion chamber 22.

(12) Fuel injector receiving bore 25 is a stepped bore which includes at least two sections of distinct diameter such that a fuel injector receiving bore outer portion 25a is distal from combustion chamber 22 and such that a fuel injector receiving bore inner portion 25b is proximal to combustion chamber 22. Fuel injector receiving bore outer portion 25a and fuel injector receiving bore inner portion 25b are each centered about a fuel injector receiving bore axis 25c, however, fuel injector receiving bore outer portion 25a is larger in diameter than fuel injector receiving bore inner portion 25b. Fuel injector 20 includes one or more combustion seals 46 which are disposed radially between fuel injector body 24 and fuel injector receiving bore inner portion 25b, thereby preventing combustion gases from passing between the interface of fuel injector body 24 and fuel injector receiving bore inner portion 24b. A fuel injector receiving bore shoulder 25d is formed between fuel injector receiving bore outer portion 25a and fuel injector receiving bore inner portion 25b such that fuel injector receiving bore shoulder 25d is perpendicular, inclined, or a combination of perpendicular and inclined to fuel injector receiving bore axis 25c.

(13) Now with reference to FIGS. 2-6, fuel line assembly 18 includes a fuel line 52 which extends along a fuel line axis 52a. Fuel line 52 is tubular such that fuel line 52 includes a fuel line tubular wall 52b extending along fuel line axis 52a and includes a fuel line inner surface 52c and a fuel line outer surface 52d. Fuel line assembly 18 also includes a plurality of fuel injector sockets 54 which are fixed to fuel line 52. Each fuel injector socket 54 is tubular and configured to receive a respective one of fuel injectors 20 as will be described later in greater detail. Fuel line assembly 18 also includes a plurality of alignment tubes 58 which provide alignment between fuel injector sockets 54 and fuel line 52 during manufacturing of fuel line assembly 18 and also provide pulsation damping during operation of fuel injectors 20. Fuel line 52, fuel injector sockets 54, and alignment tubes 58 will be described in greater detail in the paragraphs that follow.

(14) Fuel line 52 will now be described in greater detail. Fuel line 52 is made of metal and may be, by way of non-limiting example only, stainless steel such as 304 stainless steel in order to be resistive to corrosive fuel such as gasoline. Unlike typical fuel rails commonly utilized to supply fuel to fuel injectors 20, fuel line 52 is relatively small in diameter and has a thin wall thickness. Fuel rails typically have an outside diameter on the order of 21 mm, an inside diameter on the order of 13 mm, and a wall thickness on the order of 4 mm where the wall thickness is the radial distance from fuel line inner surface 52c to fuel line outer surface 52d in a direction perpendicular to fuel line axis 52a. In contrast, and by way of non-limiting example only, fuel line 52 has an outside diameter of 10 mm or less, an inside diameter of 6 mm or less, and a wall thickness of 2 mm or less. In one example, the outside diameter of fuel line 52 is 8 mm and the inside diameter is 5 mm, resulting in a wall thickness of 1.5 mm. As shown in the figures, fuel line axis 52a need not be linear for its entire length, but may be curved where fuel line 52 is bent as needed to change the direction of fuel line 52 in order to accommodate other elements of internal combustion engine 12. However, portions of fuel line axis 52a are linear, particularly where fuel injector sockets 54 are fixed to fuel line 52. In the sections where fuel line axis 52a is linear, fuel line outer surface 52d is cylindrical in cross section when sectioned perpendicular to fuel line axis 52a such that fuel line outer surface 52d is centered about fuel line axis 52a. Fuel line 52 includes a respective fuel line aperture 52e for each fuel injector socket 54 such that each fuel line aperture 52e extends from fuel line outer surface 52d to fuel line inner surface 52c. Each fuel line aperture 52e extends along, and is centered about, a respective fuel line aperture axis 52f which may be perpendicular to, and intersects with, fuel line axis 52a. Each fuel line aperture 52e is preferably cylindrical in shape.

(15) The connection of each fuel injector socket 54 to fuel line 52 may be substantially the same, consequently, the subsequent description will refer to one fuel injector socket 54 and one alignment tube 58 with the understanding that the description applies equally to each fuel injector socket 54, each alignment tube 58, and connection thereof to fuel line 52.

(16) Fuel injector socket 54 is made of metal and may be, by way of non-limiting example only, stainless steel such as 304 stainless steel in order to be resistive to corrosive fuel such as gasoline. Fuel injector socket 54 extends along a fuel injector socket axis 54a, which may be coincident with fuel line aperture axis 52f as shown in the figures, from a fuel injector socket first end 54b to a fuel injector socket second end 54c. Fuel injector socket 54 includes a fuel injector socket fixation saddle 54d which is concave and which is located at fuel injector socket first end 54b such that fuel injector socket fixation saddle 54d has a concave surface 54e which faces toward fuel line 52 and such that fuel line 52 is received within fuel injector socket fixation saddle 54d. Concave surface 54e is preferably complementary to fuel line outer surface 52d, and consequently, is preferably cylindrical to match fuel line outer surface 52d. As used herein, cylindrical is not limited to being a full cylinder, but also encompasses a portion of a cylinder. Fuel injector socket 54 also has a fuel injector socket receiving bore 54f extending thereinto from fuel injector socket second end 54c such that fuel injector inlet conduit 50 is received within fuel injector socket receiving bore 54f and sealed thereto, for example with an O-ring as illustrated in the figures. Fuel injector socket receiving bore 54f is cylindrical in shape and is preferably centered about fuel injector socket axis 54a. Fuel injector socket 54 also has a fuel injector socket aperture 54g which extends from concave surface 54e to fuel injector socket receiving bore 54f. Fuel injector socket aperture 54g is preferably centered about fuel injector socket axis 54a and is preferably stepped as shown. Consequently, fuel injector socket aperture 54g may have a fuel injector socket aperture outer portion 54h which is proximal to concave surface 54e and a fuel injector socket aperture inner portion 54i which is proximal to fuel injector socket receiving bore 54f. Each of fuel injector socket aperture outer portion 54h and fuel injector socket aperture inner portion 54i are preferably cylindrical in shape such that fuel injector socket aperture outer portion 54h is larger in diameter than fuel injector socket aperture inner portion 54i, thereby forming a fuel injector socket aperture shoulder 54j where fuel injector socket aperture outer portion 54h and fuel injector socket aperture inner portion 54i meet such that fuel injector socket aperture shoulder 54j is travers to fuel injector socket axis 54a and preferably is perpendicular to fuel injector socket axis 54a.

(17) Fuel injector socket 54 may also include a mounting boss 56 fixed there to which is used to secure fuel line assembly 18 to internal combustion engine 12. Mounting boss 56 may be integrally formed as a single piece of material with fuel injector socket 54 or may alternatively be formed from a separate piece of material and fixed to fuel injector socket 54, by way of non-limiting example only, by welding. Mounting boss 56 includes a mounting boss aperture 56a extending therethrough along a mounting boss aperture axis 56b such that mounting boss aperture axis 56b may be parallel to fuel injector socket axis 54a. Mounting boss aperture 56a receives a mounting bolt 57 therethrough which threadably engages cylinder head 26, thereby clamping mounting boss 56 to cylinder head 26 and fixing fuel line assembly 18 to internal combustion engine 12.

(18) Alignment tube 58 will now be described in greater detail. Alignment tube 58 extends along an alignment tube axis 58a, which may be coincident with fuel line aperture axis 52f and fuel injector socket axis 54a as shown in the figures, from an alignment tube first end 58b which is proximal to fuel line inner surface 52c to an alignment tube second end 58c which is proximal to fuel injector socket receiving bore 54f. An alignment tube passage 58d extends through alignment tube 58 from alignment tube first end 58b to alignment tube second end 58c, thereby providing fluid communication from fuel line inner surface 52c to fuel injector socket receiving bore 54f. Alignment tube passage 58d may preferably be centered about alignment tube axis 58a as shown in the figures. The outer periphery of alignment tube 58 may be stepped as shown such that alignment tube 58 includes an alignment tube first portion 58e which extends from alignment tube first end 58b toward alignment tube second end 58c and also includes an alignment tube second portion 58f which extends from alignment tube first portion 58e to alignment tube second end 58c. Alignment tube first portion 58e may be cylindrical in shape, except for a lead-in portion 58g which may be radiused or chamfered in order to facilitate insertion into fuel line aperture 52, wherein alignment tube first portion 58e is larger in diameter than alignment tube second portion 58f. As a result of the stepped nature of the outer periphery of alignment tube 58 an alignment tube shoulder 58h is formed where alignment tube first portion 58e and alignment tube second portion 58f meet such that alignment tube shoulder 58h is travers to alignment tube axis 58a and is preferably perpendicular to alignment tube axis 58a. Alignment tube shoulder 58h is in contact with fuel injector socket aperture shoulder 54j, thereby axially positioning alignment tube 58. An alignment tube outer peripheral surface 58i extends circumferentially around alignment tube first portion 58e and alignment tube second portion 58f such that a section of alignment tube outer peripheral surface 58i is circumferentially surrounded by fuel line aperture 52e, another section of alignment tube outer peripheral surface 58i is circumferentially surrounded by fuel injector socket aperture outer portion 54h, and yet another section of alignment tube outer peripheral surface 58i is circumferentially surrounded by fuel injector socket aperture inner portion 54i. A section of alignment tube first portion 58e which is closest to alignment tube first end 58b is located within fuel line aperture 52e, either in an interference fit or a clearance fit; a section of alignment tube first portion 58e which is closest to alignment tube shoulder 58h is located within fuel injector socket aperture outer portion 54h, either in an interference fit or a clearance fit; and alignment tube second portion 58f is located within fuel injector socket aperture inner portion 54i, either in an interference fit or a clearance fit. However, it is preferable that at least alignment tube second portion 58f is located within fuel injector socket aperture inner portion 54i in an interference fit, thereby retaining alignment tube 58 and preventing alignment tube 58 from moving out of position.

(19) The diameter of alignment tube passage 58d and the length of alignment tube 58 from alignment tube first end 58b to alignment tube second end 58c (and consequently the length of alignment tube passage 58d along alignment tube axis 58a) can be selected in order to minimize or eliminate pressure pulsations created by the rapid cyclic opening and closing of fuel injectors 20. The diameter of alignment tube passage 58d and the length of alignment tube 58 from alignment tube first end 58b may be selected based on the specific details of fuel system 10 where the diameter and length may be determined through one or more of mathematical calculation, computer modeling, and empirical testing.

(20) A braze material 60 is used to prevent leakage of fuel between the interface of fuel line 52 and fuel injector socket 54 and also to fix fuel injector socket 54 to fuel line 52. As shown in FIG. 3, braze material 60 may be provided as a ring, contoured to match fuel line outer surface 52d and concave surface 54e, in which opposing surfaces 60a and 60b of braze material 60 are placed against fuel line outer surface 52d and concave surface 54e of fuel injector socket 54 respectively such that and a braze material aperture 60c, which extends therethrough from opposing surface 60a to opposing surface 60b, allows alignment tube 58 to pass therethrough. Braze material 60 may be, by way of non-limiting example only, copper or a copper alloy, or any other brazing material compatible with the particular materials selected for fuel line 52 and fuel injector socket 54 where the selection of the particular material would be known to a practitioner of ordinary skill in the art. After fuel line 52, fuel injector socket 54, alignment tube 58, and braze material 60 are assembled to each other, fuel line assembly 18 may be placed in a brazing oven where the temperature of fuel line assembly 18 is raised to be above the melting temperature of braze material 60 to cause braze material 60 to flow, thereby causing braze material 60 to seal and join fuel injector socket 54 to fuel line 52 when cooled. It should be noted that the stepped nature of fuel injector socket aperture 54g and alignment tube 58 minimizes the likelihood of braze material 60 from flowing past the interface of fuel injector socket aperture 54g and alignment tube 58. The brazing process will not be discussed further herein and would be known to a practitioner of ordinary skill in the art. In one non-limiting alternative, braze material 60 may be omitted and sealing and fixation of fuel injector socket 54 to fuel line 52 may be provided by welding fuel injector socket 54 to fuel line 52.

(21) Fuel line assembly 18 as described herein allows for use of fuel line 52 having a relatively small wall thickness which can be easily shaped to be non-linear, thereby allowing for easier packaging of fuel line assembly 18 on internal combustion engine 12. Furthermore, pressure pulsation damping characteristics can be easily tailored by selecting the diameter and length of alignment tube passage 58d. Even furthermore, alignment of fuel injector socket 54 to fuel line 52 can be maintained during manufacturing of fuel line assembly 18 through use of alignment tube 58.

(22) While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but rather only to the extent set forth in the claims that follow.