The field of the present invention is fuel delivery systems. More particularly, the present invention relates to a fuel delivery system for vehicular applications comprising one or more fuel injector assemblies, at least a portion of which are affixed to a fuel rail of the fuel delivery system.
Fuel delivery systems for fuel-injected engines used in various types of on-road and off-road vehicles typically include one or more fuel rails having a plurality of fuel injectors associated therewith. In many known fuel delivery systems, one or more fuel rails are provided which include a plurality of apertures in which injector sockets or cups are affixed. The fuel injectors are then inserted into the injector cups so as to allow for the fuel flowing in the fuel rail to be communicated to the fuel injectors. The fuel communicated from the fuel rail to the fuel injectors is then typically injected into an intake manifold or the like.
In many of these systems, the fuel injector cups are separate from the fuel rail, but affixed thereto using known attachment methods. For example, the injector cup may have a neck portion that extends into the aperture in the fuel rail and beyond the inside surface of the fuel rail. In this instance, the cup can be affixed to the rail by performing known attachment methods such as peening, swaging, staking or otherwise expanding the portion of the neck extending into the fuel rail to resist removal of the cup from the fuel rail, while at the same time creating a substantially fluid-tight seal. In other systems, the cup may be affixed to the fuel rail by way of a brazing process or the like.
In any event, one or more O-rings are often required in order to prevent or at least reduce potential leak paths and hydrocarbon permeation paths between, for example, the injector cup and the fuel injector disposed therein. While these systems have proven to work, they are not without their disadvantages. For example, the need for O-rings and precision sealing surfaces in these systems adds costs to the overall system. Additionally, these systems have not optimally reduced the permeation of hydrocarbons from the system.
Accordingly, there is a need for a fuel delivery system that will minimize and/or eliminate one or more of the above-identified deficiencies.
The present invention is directed towards a vehicular fuel delivery system. In accordance with one exemplary embodiment of the invention, the fuel delivery system includes a fuel rail having at least one feed, and at least one fuel injector assembly comprising a fuel injector and an outer housing. In accordance with this embodiment of the invention, the fuel injector assembly is permanently affixed to the fuel rail so that the feed of the fuel rail is in fluid communication with an inlet of the fuel injector, and wherein at least a portion of the fuel injector assembly is further configured to be replaceable. Further features and advantages of the present invention will become more apparent to those skilled in the art after a review of the invention as it is shown in the accompanying drawings and detailed description.
Referring now to the drawings wherein like reference numerals are used to identify identical components in the various views,
Fuel rail 12 is configured to communicate pressurized fuel from a fuel source (not shown) to one or more fuel injectors coupled thereto, which then injects the fuel into the intake manifold of the fuel injected engine associated therewith. As shown in
With reference to
In one preferred embodiment, core 20 is comprised of an aluminum alloy, such as, for exemplary purposes only, 3000 series aluminum (i.e., manganese is the major alloying component), 5000 series aluminum (i.e., magnesium is the major alloying component), or 6000 series aluminum (i.e., magnesium and silicon are the major alloying components). Accordingly, core 20 can take the form of many different materials of which aluminum is a part, including, but not limited to, those identified with particularity above. Additionally, in the embodiment wherein fuel rail 12 is a tube comprising aluminum material, the aluminum material may be, for exemplary purposes only, any one of the aluminum alloys described above, however, the present invention is not so limited.
As with core 20, coating layer 24 can be comprised of one of many different types of thermoplastic material. In one preferred embodiment layer 24 is comprised of “polyamide 12” (commonly known in the art as “PA 12” or “nylon 12”). However, any suitable thermoplastic coating can be used. For example, in alternate embodiments, layer 24 is formed of “polyamide 6”, “polyamide 6.6”, “polyamide 11”, polyphenylene sulfide (PPS), polyphthalamide (PPA), or polybutylene napthalate (PBN), for example. It should be noted, however, that this list is meant to be for exemplary purposes only and not intended to be all inclusive. Accordingly, those of ordinary skill in the art will recognize that other thermoplastic materials can be used to create coating layer 24. As will be described in greater detail below, the thermoplastic layer 24 of fuel rail 12 is provided, at least in part, to facilitate a strong bond between fuel rail 12 and fuel injector assembly 14 when they are affixed together. An example of a commercially available thermoplastic coated tube that is suitable for use in the present invention is that offered by Hydro Aluminum Precision Tubing of Tonder, Denmark, under the trademark HYCOT®.
As will be described in greater detail below, fuel injector assembly 14 generally includes a fuel injector 26 and an outer housing 28 in which fuel injector 26 is disposed. Fuel injector 26 includes an inlet 30 at one end, an outlet or nozzle 32 at the other end, and a flow channel 34 therebetween for communicating fuel from inlet 30 to outlet 32. As will be described in greater detail below, inlet 30 of each respective fuel injector is configured to be in fluid communication with a respective feed 18 of fuel rail 12. This arrangement allows for the fuel in fuel rail 12 to be communicated to the engine (i.e., through the intake valves of the intake manifold thereof) that is in fluid communication with outlet 32 of injector 26.
With reference to
With continued reference to
Irrespective of whether fuel rail 12 is a tube formed of metal or whether it is a thermoplastic coated tube, to assemble fuel rail 12 and receptor 36, flow channel 42 is aligned with feed 18 of fuel rail 12, and then the contact region between flange 38 (i.e., mating surface 44) and fuel rail 12 is heated to weld fuel rail 12 and flange 38 together. For example, in the embodiment wherein fuel rail 12 is a thermoplastic coated tube, polymer coating 24 of fuel rail 12 and the proximal surface material of flange 38 melt and intermix and weld together. The weld creates both a structural joint between receptor 36 and fuel rail 12, as well as a sealing joint to prevent, or at least reduce, the permeation of hydrocarbons or the leaking of fuel from fuel delivery system 10. In a preferred embodiment, the contact region is subjected to an induction welding process. However, other known processes, such as, for example, ultrasonic welding, hot plate welding or spin welding, to name a few, could also be used.
With reference to
As briefly mentioned above, in this embodiment of fuel delivery system 10, injector assembly 14 is configured to be permanently affixed to receptor 36, and therefore, fuel rail 12. In order to facilitate such an arrangement, receptor 36 includes an engagement surface 50 that is disposed around the rim of cup portion 40. Fuel injector assembly 14 likewise includes an engagement flange 52, which, in a preferred embodiment, extends circumferentially around the outer housing of fuel injector assembly 14. However, it will be appreciated by those skilled in the art that flanges having other shapes and configurations could be used in place of the illustrated circumferential flange. In a preferred embodiment, engagement flange 52 is formed of thermoplastic material. For example, in one exemplary embodiment, flange 52 is formed of “polyamide 6”. Using this particular thermoplastic material serves to facilitate a strong, non-leaking and non-permeable bond between flange 52 and engagement surface 50 of receptor 36, which, in a preferred embodiment, is also formed of “polyamide 6”. It should be noted, however, that one of ordinary skill in the art will appreciate that other types of thermoplastic materials, such as those described above with respect to coating layer 24, could also be used to construct engagement flange 52.
To assemble fuel injector assembly 14 and receptor 36 together, injector assembly 14 is inserted into the cup portion 40 of receptor 36. Cup portion 40 is sized and configured such that inlet 30 of injector 26 is disposed within flow passage 42 of receptor 36 to allow for fuel to flow between feed 18 of fuel rail 12 and injector inlet 30. When assembled, engagement surface 50 of receptor 36 and engagement flange 38 of injector assembly 14 abut each other, engagement surface 50 and engagement flange 52 are heated such that the thermoplastic material forming engagement surface 50 and the proximal surface material of engagement flange 52 melt and intermix and weld together. This weld creates both a structural joint between receptor 36 and fuel injector assembly 14, as well as a sealing joint to prevent, or at least reduce, the permeation of hydrocarbons or the leaking of fuel from fuel delivery system 10, thereby obviating the need for O-rings between injector 26 and injector cup 40. In a preferred embodiment, the engagement surface 50 and engagement flange 52 are subjected to an induction welding process. However, other known processes, such as, for example, ultrasonic welding, hot plate welding, spin welding and various adhesives, to name a few, could also be used. The result of this process is a fuel delivery system 10 having a fuel injector assembly that is permanently affixed to the fuel rail.
As described above, if any part of fuel injector assembly 14 requires maintenance or replacement, receptor 36 is cut at cut notch 46. The cut is through the thermoplastic housing to the inner surface of cup 40 (i.e., injector 26 disposed within receptor 36 remains in tact) and extends circumferentially around the perimeter of receptor 36. Once cut, fuel injector assembly 14 can be removed. Accordingly, cut notch 46 is located between engagement surface 50 and flange 38 of receptor 36. Additionally, the location of cut notch 46 is such that the remaining cup portion 40 is of sufficient depth, size and configuration to receive a replacement injector assembly that is of the same or similar construction as fuel injector assembly 14 described above. However, one difference between the original fuel injector assembly 14 and the replacement injector assembly is that the replacement injector assembly is not welded to receptor 36, but rather abuts an outer surface of the rim of cup 40 and is held in place with a fuel injector retention clip, as described above.
With reference to
As with flanged portion 38 described above, flange 38′ is shaped so as to have the same contour or shape as the outer surface of the fuel rail 12 to which fuel injector assembly 14 is to be affixed. Accordingly, in the embodiment illustrated in
In an exemplary embodiment, housing 28′ is formed of thermoplastic material that is molded over fuel injector 26 using known over-molding processes wherein dies are used to define the shape of housing 28′, including flange 38′. The arrangement of fuel injector 26 being disposed within a one piece housing 28′ serves to provide a seal between injector 26 and a corresponding cup formed within housing 28′ to prevent, or at least reduce, the permeation of hydrocarbons or the leaking of fuel from fuel delivery system 10′, thereby obviating the need for O-rings between injector 26 and the corresponding cup formed within housing 28′. In a preferred embodiment, housing 28′ is formed of “polyamide 6”, however, it should be noted that one of ordinary skill in the art will appreciate that other types of thermoplastic materials, such as those described above with respect to coating layer 24, could be used to construct housing 28′. As will be described in greater detail below, the use of a thermoplastic material for housing 28′, and more specifically flange 38′, serves to facilitate a strong, non-leaking and non-permeable bond between flange 38′ and fuel rail 12 when the two components are coupled together.
With reference to
With continued reference to
In addition to being configured to be permanently affixed to fuel rail 12, at least a portion of fuel injector assembly 14 is configured to be replaceable. As illustrated in
In a preferred embodiment, fuel injector assembly 14′ further includes a groove 48 in housing 28′. Groove 48 is configured to receive a fuel injector retention clip. In the embodiment illustrated in
In a preferred embodiment, fuel injector assembly 14′ still further includes insert sleeve 54 that is disposed within housing 28′ and between a portion of injector 26 proximate inlet 30 and thermoplastic layer 56. Insert sleeve 54 is operative to serve as a spacer between injector 26 and layer 56, and, as will be described in greater detail below, is configured to be removed from housing 28′ when injector 26 is removed. In a preferred embodiment, insert sleeve 54 is formed of a polymeric material such as, for example, TEFLON®. However, in other alternate preferred embodiments, sleeve 54 is formed of materials such as stainless steel, polyphenylene sulfide (PPS), or any other high temperature tolerant material that will not melt during molding processes to which fuel injector assembly 14′ is subjected.
In a preferred embodiment, fuel injector assembly 14 yet still further includes thermoplastic layer 56 that is disposed within housing 28′ and between the inner surface of housing 28 and insert sleeve 54. As shown in
With continued reference to
Accordingly, when the replacement of injector 26 is necessary, housing 28′ is cut at cut notch 46. The cut is only through the thermoplastic housing 28′, such that injector 26 is left in tact, and it extends circumferentially around the perimeter of housing 28′. The portion of housing 28′ that is on the opposite side of cut notch 46 from flange 38′ is pulled away from fuel rail 12. This causes fuel injector 26 to likewise be pulled away from fuel rail 12 and removed from fuel injector assembly 14′, and thus, fuel delivery system 10′. Once injector 26 is removed, sleeve 54 is then removed, thereby leaving behind receptor 36′, which includes a fuel injector cup 40′, that remains affixed to fuel rail 12 within which a replacement injector assembly (such as that illustrated in
It should be further noted that other methods exist by which fuel injector assembly 14 and injector 26, in particular, can be permanently affixed to fuel rail 12. For example, in an alternate embodiment wherein housing 28 does not include flange 38, fuel injector assembly 14 is over-molded onto fuel rail 12. In one such exemplary embodiment provided for exemplary purposes only, fuel rail 12 and fuel injector assembly 14 are arranged together, the connection point is then clamped over using a clamshell molding die, and then the connection is over-molded so as to create a permanent joint between fuel rail 12 and injector assembly 14. Accordingly, in this embodiment, flange 38 is essentially created during the process in which injector assembly 14 is affixed to fuel rail 12. In any event, the description above applies to this embodiment with equal force as that applied to the preferred embodiments above.
With reference to
In a second step 66, at least one fuel injector assembly 14 is provided. Fuel injector assembly 14 is configured to be permanently affixed to fuel rail 12 so that feed 18 of fuel rail 12 is in fluid communication with an inlet 30 of the fuel injector 26, and at least a portion of fuel injector assembly 14 is configured to be replaceable. In an exemplary embodiment, housing 28 is comprised of a thermoplastic material, such as, for example, “PA 6”. In a preferred embodiment, step 66 comprises providing a fuel injector assembly 14 wherein the outer housing 28 of fuel injector assembly 14 includes an engagement flange 52 configured to be permanently affixed to an engagement surface 50 of a receptor 36 that is affixed to fuel rail 12. In an alternate preferred embodiment, step 66 includes providing a fuel injector assembly 14 wherein the outer housing 28 thereof includes an integral flange 38 configured to be permanently affixed to fuel rail 12, as well as both a cut notch 46 and groove 48 disposed therein.
In a third step 68, fuel injector assembly 14 is permanently affixed to the outer surface of fuel rail 12. In a preferred embodiment in which receptor 36 is affixed to fuel rail 12, flange 52 of fuel injector assembly 14 is welded onto engagement surface 50 of receptor 36. In an exemplary embodiment, both engagement surface 50 and engagement flange 52 are formed of thermoplastic materials. In an alternate preferred embodiment wherein fuel injector assembly 14 includes integrally formed flange 38, flange 38 is welded directly onto fuel rail 12. In an exemplary embodiment, flange 38 and fuel rail 12 comprise thermoplastic material. In yet another alternate embodiment, fuel injector assembly 14 is over-molded onto fuel rail 12. In each of these embodiments any one of a number of welding processes can be employed, such as, for example, induction welding, ultrasonic welding, hot plate welding or spin welding, to name a few, can be used.
While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it is well understood by those skilled in the art that various changes and modifications can be made in the invention without departing from the spirit and scope of the invention.