The present invention relates to a fuel line assembly which supplies fuel to a fuel injector of a fuel consuming device and more particularly to a connection between a fuel line and a fuel injector socket of the fuel line assembly.
Fuel injection systems that deliver fuel to fuel consuming devices, for example internal combustion engines, have been known for many years. In modern internal combustion engines, it is increasingly common to provide fuel injectors which inject fuel, for example gasoline, directly into combustion chambers of the internal combustion engine. These internal combustion engines commonly include multiple combustion chambers, and consequently, each combustion chamber is provided with a respective fuel injector to inject fuel therein. A common conduit, typically referred to as a fuel rail, includes an inlet which receives fuel from a fuel source, such as one or more fuel pumps, and also includes a plurality of injectors sockets which each receive an inlet end of a respective fuel injector in order to communicate fuel to each fuel injector.
Typical fuel rails have a large internal volume in order to aid in damping pressure pulsations created by the rapid cyclic opening and closing of the fuel injectors. For example, the inside diameter of the fuel rail may be on the order of 13 mm. In order to provide structural integrity at the pressures experienced by the fuel rail, the outside diameter is on the order of 31 mm, thereby resulting in a wall thickness on the order of 4 mm. The large diameter and wall thickness of conventional fuel rails requires the fuel rail to be linear, and consequently, does not allow for the fuel rail to be routed around other components of the internal combustion engine. As a result, it may be desirable to replace the fuel rail with a fuel line which is sized to be similar to a supply line which supplies fuel from the fuel pump to the conventional fuel rail. For example, the fuel line may have 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 which allows the fuel line to bent and formed into non-linear shapes in order to be routed around other components of the internal combustion engine. However, using such a fuel line decreases the pressure pulsation damping attributes of the conventional fuel rail having a large internal volume. Furthermore, the conventional techniques for joining the fuel injector sockets to the fuel rail may not translate well to joining the fuel injector socket to such a fuel line due to the drastic reduction in size of the fuel line compared to the fuel rail. Additional benefits of using such a fuel line are to reduce mass, reduce cost, and reduce the number of connections by using a single fuel tube to provide fluid communication from the fuel pump to the fuel injectors.
What is needed is a fuel line assembly which provides a connection to a fuel injector which minimizes or eliminates one or more of the shortcomings set forth above.
Briefly described, a fuel line assembly is provided which supplies fuel to a fuel injector of a fuel consuming device. The fuel line assembly includes 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 the fuel line outer surface to the 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, the fuel injector socket having a fuel injector socket fixation saddle which is concave at the fuel injector socket first end within which the fuel line is received such that the fuel injector socket fixation saddle has a concave surface facing toward the fuel line, the fuel injector socket also having a fuel injector socket receiving bore extending thereinto from the fuel injector socket second end which is configured to receive the fuel injector therewithin, the fuel injector socket also having a fuel injector socket aperture extending from the concave surface to the fuel injector socket receiving bore; and an alignment tube extending from an alignment tube first end to an alignment tube second end, the alignment tube having an alignment tube passage extending therethrough from the alignment tube first end to the alignment tube second end, the alignment tube also having an alignment tube outer peripheral surface such that a portion of the alignment tube outer peripheral surface is circumferentially surrounded by the fuel line aperture and such that another portion of the alignment tube outer peripheral surface is circumferentially surrounded by the fuel injector socket aperture such that the alignment tube passage provides fluid communication between the fuel line inner surface and the fuel injector socket receiving bore.
The fuel line assembly as described herein allows the fuel line to have a relatively small wall thickness which can be easily shaped to be non-linear, thereby allowing for easier packaging of the fuel line assembly on internal combustion engines. Furthermore, pressure pulsation damping characteristics can be easily tailored by selecting the diameter and length of the alignment tube passage. Even furthermore, alignment of the fuel injector socket to the fuel line can be maintained during manufacturing of the fuel line assembly through use of the alignment tube.
This invention will be further described with reference to the accompanying drawings in which:
Referring initially to
Referring now to
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.
Now with reference to
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.
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.
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.
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.
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.
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.
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
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.
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.
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Number | Date | Country |
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2012150072 | Nov 2012 | WO |