The field of the present invention is fuel delivery systems. More particularly, the present invention relates to an arrangement for attaching one or more fuel injectors to a fuel rail in a gasoline direct injection fuel delivery system.
Fuel delivery systems for direct injection applications, such as, for example, 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 such applications, the fuel rails may include a plurality of apertures in which injector sockets or cups are affixed. The fuel injectors are then inserted into and coupled with 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 communicated to the combustion chamber of the engine. Accordingly, in these arrangements the fuel injectors are sandwiched between the fuel rail and a corresponding cylinder head of the engine.
One drawback of such direct injected systems, however, is that the sandwiched arrangement of the fuel injector causes undesirable noise in the system. Prior attempts at eliminating or at least reducing this noise have included suspending the injector from the fuel rail. To do so, an O-ring seal and a fuel injector clip (due to the high pressure attendant in the system (i.e., on the order of 10 MPa or more)) are used to seal the connection between the fuel rail and fuel injector, and to hold and retain the injector in the correct position. Accordingly, the sealing and retention functions are performed separately. While such an arrangement may reduce the noise in the system, it requires additional components (e.g., the O-ring and the clip), which in turn increases both the weight and cost of the overall system and the corresponding manufacturing process.
Therefore, 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 direct to a fuel delivery system. The inventive system comprises a fuel rail defining a first longitudinal axis and having an inlet, a feed outlet and a receptor associated with the feed outlet. The feed outlet defines a second axis extending therethrough that is perpendicular to the first longitudinal axis. The system further comprises a fuel injector having an inlet and an outlet. The inlet of the injector is configured for communication with the feed outlet of the fuel rail and the outlet of the injector is configured for communication with a combustion chamber of an engine associated with the system. The fuel injector further defines a third axis extending through the inlet and outlet thereof that is perpendicular to the first axis and substantially coaxial with the second axis. The inventive system still further includes a first feature disposed on one of the receptor and injector and a second feature disposed on the other of the receptor and injector. The first and second features cooperate to form a seal between the fuel injector and the receptor, and to maintain the axial alignment of the components. Additional apparatus corresponding to the inventive fuel delivery system and the constituent components thereof are also presented.
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,
As shown in
With continued reference to
Inlet 26 is configured for connection to a fuel source (not shown), such as, for example, a fuel tank of a vehicle, in order to communicate fuel from the fuel source to fuel rail 12, and fluid passageway 22, in particular.
Feed outlet 28, which, in an exemplary embodiment, comprises an aperture in body 16 of fuel rail 12 and defines an axis 32 extending therethrough and perpendicular to axis 24 of fuel rail 12, is configured to be in fluid communication with the inlet of a corresponding fuel injector 14 to allow fuel in fuel rail 12 to be communicated to fuel injector 14, and ultimately, the engine associated with fuel delivery system 10. In an exemplary embodiment, fuel rail 12 includes a plurality of feed outlets 28 (and therefore, as will be described below, a corresponding number of receptors 30) so as to provide fuel to a number of corresponding fuel injectors 14. However, for the sake of simplicity alone, fuel delivery system 10 will be described hereinafter as having a single feed outlet 28, and therefore, a single fuel injector 14.
As briefly described above and with particular reference to
In an exemplary embodiment, receptor 30 is integrally formed with rail 12. However, in an alternate embodiment, receptor 30 is configured to be mounted or otherwise affixed to rail 12. In latter embodiment, receptor 30 may include a mounting flange 40 that may be affixed to rail 12 by way of conventional methods, such as, for example, brazing or welding processes. Although not necessarily required, in an exemplary embodiment, flange 40 is sized and shaped to match the particular contour of the outer surface of rail body 16. Accordingly, in an embodiment wherein fuel rail 12 has a circular cross-section, flange 40 has an arcuate shape. Alternatively, however, flange 40 may have a rectangular or square shape when fuel rail 12 has a corresponding rectangular or square cross-section. Accordingly, those of ordinary skill in the art will recognize that flange 40 may have many different shapes depending on the particular cross-section of rail 12. In an alternate exemplary embodiment, receptor 30 does not include flange 40, but rather is otherwise directly affixed to the outer surface of rail body 16 using known affixation methods (i.e., brazing, welding, and/or other suitable processes).
In addition to the components described above, and perhaps best shown in
In an exemplary embodiment illustrated, for example, in
With continued reference to
In an exemplary embodiment, second feature 44 includes a seat 60 and a threaded portion 62. As briefly described above, first and second features 42, 44 are complementary with each other. Accordingly, seat 60 is sized and shaped to receive distal at least a portion of distal end 54, and threaded portion 62 is configured to mate with threaded portion 48 of first feature 42. More particularly, threaded portion 62 of second feature 44 is configured to be mated with the inner threaded surface of the nut comprising threaded portion 48 so as to create a compression fitting therebetween.
In the particular embodiment illustrated in
In an alternate embodiment illustrated in
Regardless of how first feature 42 and receptor 30 are associated together, in this embodiment, second feature 44 is associated with injector 14. As illustrated in
With reference to
With continued reference to
While the description set forth above provides that first feature 42 is associated with receptor 30 and second feature 44 is associated with injector 14, one of ordinary skill in the art will recognize and appreciate that the features may be reversed such that first feature 42 is associated with injector 14, while second feature 44 is associated with receptor 30. More particularly, in an alternate embodiment, receptor 30 is formed to have seat 60 disposed therein and also to have a threaded surface 62 proximate seat 60. In this embodiment, opening 38 of receptor 30 extends into seat 60. On the other hand, in this embodiment, injector 14 includes supporting member 46 and threaded portion 48 disposed at first end 78 thereof proximate injector inlet 82. Accordingly, as described above, seat 60, now part of receptor 30, is configured to receive distal end 54 of supporting member 46, now associated with injector 14; and the nut, now associated with injector 14, is configured to be threaded onto threaded portion 62, now disposed on receptor 30. Therefore, first and second portions 42, 44 may be alternatively associated with either injector 14 or receptor 30, and thus, the description set forth above relating to first and second features 42, 44 and the constituent parts thereof applies to this embodiment with equal force.
Accordingly, in the exemplary embodiments described above wherein first and second features 42, 44 have complementary threaded portions, the mating of these portions create a compression fitting that serves to seal the coupling of fuel injector 14 and receptor 30, to reinforce the suspension of fuel injector 14, and to retain injector 14 in place in axial alignment with both fuel rail outlet 28 and combustion chamber 88. The axial alignment and the mating of features 42, 44 serve a number of purposes. First, when in axial alignment, injector outlet 84 engages the cylinder head and reaches the combustion chamber 88, which forces injector 14 into rigid alignment. Second, in a normal O-ring type joint, if the connection to fuel rail 12 is misaligned, injector side loading may result. This is due to the load applied to the fuel rail and injector as a result of the high pressure in the system (i.e., on the order of 10 MPa), which may cause the injector to want to “pop out” of the injector cup unless firmly secured to the cup/rail. Additionally, a load created by the combustion pressure resulting from a combustion event occurring in combustion chamber 88 is applied substantially coincident to axis 86 of injector 14 (and, therefore, normal to axis 24 of rail 12) and can have the effect of causing a moment, such as a twisting moment, to be applied to injector 14 and/or fuel rail 12. Accordingly, the axial alignment combined with the rigid connection and seal formed by first and second features 42, 44 serves to prevent such occurrences, while also allowing some measure of misalignment.
It should be noted that while the only embodiment of first and second features 42, 44 that was described above in detail was one in which first and second features 42, 44 have threaded portions, the present invention is not meant to be so limited. Rather, other configurations and/or arrangements exist that may be implemented. For example, in one alternate exemplary embodiment, fuel injector 14 can be affixed to receptor 30 or fuel rail 12 using a brazing or welding technique. In such an embodiment, first and second features 42, 44 comprise complementary flanges that can be welded or brazed together, for example. Accordingly, those of ordinary skill in the art will recognize that other arrangements and configurations exist that can be implemented to carry out the same function and purpose described above.
In an exemplary embodiment illustrated in
In an exemplary embodiment, mount 90 is comprised of the combination of a mounting bracket 94, one or more elastomer isolators 96, one or more washers 98, a compression limiter 100 and a bolt 102. As illustrated in
In operation, elastomer isolators 961, 962 serve to allow rail 12 to “float” rather than to be hard mounted. Washers 981, 982 are provided so that in the event the full pressure of the system forces the rail up or down, washers 981, 982 limited the amount of movement. Compression limiter 100 serves as a mounting surface for bolt 102 and is provided to prevent bolt 102 from being over-tightened, which could damage the elastomer isolators, as well as to limit the movement of washers 981, 982. It should be noted, however, that the present invention is not limited to such a mounting arrangement. Those of ordinary skill in the art will recognize that other components and arrangements exist that may serve the same function and purpose of the mounting arrangement described above. For example, in alternate embodiments, grommets, damping springs, displacement limiters, or any combination of any of the above may be used in place of those components described above. Accordingly, when fuel rail 12 is mounted, the force applied by the loads created by the various pressures attendant in the system may be transferred from the injector/fuel rail combination, through force resolving mount 90, and then onto the reaction surface 92 to dissipate this pressure/force.
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.
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