Patent Application
20140103642
The present disclosure relates generally to vehicle fuel tanks, and more particularly to connection assemblies used in vehicle fuel tanks.
Vehicle fuel systems provide liquid fuel to a prime mover such as an automotive internal combustion engine. The fuel systems often include a fuel tank to hold fuel, fuel lines connected to the fuel tank for incoming and outgoing fuel, vapor lines connected to the fuel tank and to a downstream charcoal canister, and possibly other lines connected to the fuel tank. The connections between the fuel tank and lines require connection components and sometimes include a welding operation in which the connection components are welded to the fuel tank, to the lines, to each other, or a combination of these. The connections sometimes also include a clamping component that is clamped around another component. While these connections are mostly effective, the welding operation and clamping component can add cost and complexity to the fuel tanks and lines.
A fuel tank connection assembly may include a first connector and a second connector. The first connector may have one or more threads located at a first section of an interior surface, and may have one or more first screw threads located at a second section of the interior surface. The second connector may have one or more second screw threads located at an exterior surface. When the first and second connectors are brought together with a fuel tank neck tubing, the one or more threads can be threaded over an exterior surface of the fuel tank neck tubing in order to secure the first connector and the fuel tank neck tubing together. Further, the one or more first and second screw threads can be mated together in order to secure the first and second connectors together.
A fuel tank connection assembly may include a first connector, a second connector, and a fuel tank neck tubing. The first connector may have one or more self-tapping threads located at a first section of an interior surface, and may have one or more first screw threads located at a second section of the interior surface. The second connector may have one or more second screw threads located at an exterior surface. The fuel tank neck tubing may extend from a fuel tank and may communicate with an interior of the fuel tank. When the first connector, the second connector, and the fuel tank neck tubing are brought together, the one or more self-tapping threads can be threaded over an exterior surface of the fuel tank neck tubing in order to secure the first connector and the fuel tank neck tubing together. The one or more first screw threads and the one or more second screw threads can be mated together in order to secure the first and second connectors together.
A fuel tank connection assembly may include a first connector, a tube fitting, and a fuel tank neck tubing. The first connector may have one or more self-tapping threads located at a first section of an interior surface, and may have one or more first screw threads located at a second section of the interior surface. The first connector may have a first free end and a second free end, and may have a first axial extent taken between the first and second free ends. The first connector may have an axially-facing first side surface at the second free end. The tube fitting may have one or more second screw threads located at an exterior surface. The tube fitting may have a third free end and a fourth free end, and may have a first flow passage extending between the third and fourth free ends. The tube fitting may have an axially-facing second side surface located axially between the third and fourth free ends. The fuel tank neck tubing may extend from a fuel tank and may communicate with the fuel tank. The fuel tank neck tubing may have a fifth free end, and may have a second flow passage extending from the fuel tank to the fifth free end. When the first connector, the tube fitting, and the fuel tank neck tubing are brought together, i) the one or more self-tapping threads can be threaded over an exterior surface of the fuel tank neck tubing in order to secure the first connector and the fuel tank neck tubing together; ii) the one or more first screw threads and the one or more second screw threads can be mated together in order to secure the first connector and the tube fitting together; iii) the first side surface and the second side surface may make contact with each other; iv) the first flow passage and the second flow passage may communicate with each other; v) a first seal may be provided at a surface-to-surface interface between an exterior surface of the tube fitting and an interior surface of the fuel tank neck tubing; vi) a second seal may be provided at an interface of the mated one or more first and second screw threads; vii) a third seal may be provided at an interface of the threaded one or more self-tapping threads and exterior surface of the fuel tank neck tubing; viii) a fourth seal may be provided at a surface-to-surface interface between the first side surface and the second side surface; ix) the fourth free end of the tube fitting may be inserted through the fifth free end of the fuel tank neck tubing into the second flow passage to define a second axial extent between the fourth free end and the fifth free end of the overlapping tube fitting and fuel tank neck tubing; x) the first axial extent may be greater in axial length than the second axial extent; and xi) the first axial extent may axially overlap the second axial extent.
The following detailed description of preferred embodiments and best mode will be set forth with reference to the accompanying drawings, in which:
Referring in more detail to the drawings, a vehicle fuel tank connection assembly 10 can be used in a vehicle fuel system, such as an automotive fuel system with a gasoline or diesel engine, in order to serve as a coupling between a fuel tank 12 and a line 14 such as a fuel or vapor line. Liquid fuel, gas fuel, vapor, or a combination of these can then be exchanged between the fuel tank 12 and the line 14. As will be described in greater detail below, the vehicle fuel tank connection assembly 10 provides an effective sealed coupling between the fuel tank 12 and the line 14. The connection assembly 10 can cost less and have less complexity than the previously-known connections while still effectively sealing against leakage. As an aside, the terms axial, radial, and circumferential as used herein refer to directions relative to the generally cylindrical bodies of components of the connection assembly, such that axially refers to a direction along an axis of the cylindrical bodies, radially refers to a direction along a radius of the cylindrical bodies, and circumferentially refers to a direction along a circumference of the cylindrical bodies.
The vehicle fuel tank connection assembly 10 can have different designs, constructions, and components depending upon, among other considerations, the design and construction of the fuel tank 12 and of the line 14. Referring to
The first connector 16 provides a sealed coupling with the second connector 18 and with the fuel tank neck tubing 20. The first connector 16 can have different designs and constructions depending upon, among other considerations, the design and construction of the second connector 18 and of the fuel tank neck tubing 20. Referring now to
As best shown in
As best shown in
At an exterior surface 44, the tube fitting 18 can have one or more ribs 46 protruding radially-outwardly therefrom for facilitating a secure coupling with the line 14; other couplings to the line are possible including what-is-commonly-known as a fir tree profile connection. The tube fitting 18 also has a noncircular (shown as hexagonal) portion 48 and a set of second screw threads 50 at its exterior surface 44. As before, the noncircular portion 48 can accept engagement by a tool for fastening the tube fitting 18 in place. The noncircular portion 48 is located about axially midway on the body of the tube fitting 18, axially interposed between the rib 46 and the second screw threads 50 and spaced from the second end 42. An axially-facing first side surface 52 of the noncircular portion 48 is directed away from the first connector 16 in the assembled and installed state (
The fuel tank neck tubing 20 provides a sealed coupling with the first connector 16 and the tube fitting 18, and directly communicates with an interior of the fuel tank 12. The fuel tank neck tubing 20 can have different designs and constructions depending upon, among other considerations, the design and construction of the first connector 16 and of the tube fitting 18. Referring to
Still referring to
When fully assembled and installed, the axial extent A of the first connector 16 axially overlaps and radially surrounds the second free end 42 of the tube fitting 18 and the free end 62 of the fuel tank neck tubing 20. The tube fitting 18 is inserted into the fuel tank neck tubing 20 and defines an overlapped axial extent D between the respective end portions of the tube fitting and the fuel tank neck tubing. The axial extent D is itself axially overlapped by the axial extent A, and as such the axial extent A has an axial length that is greater in value than an axial length of the axial extent D. This relationship, if it exists in a particular embodiment, contributes to the effective sealing performance of the vehicle fuel tank connection assembly 10 and facilitates the provision of an interface sealing path among the components of the connection assembly and the multiple seals formed along the interface sealing path.
The interface sealing path is formed by surface-to-surface confronting contact among the first connector 16, the tube fitting 18, and the fuel tank neck tubing 20. For the purposes of description, beginning at the flow passage 60 of the fuel tank neck tubing 20, a first seal 72 can be produced at a surface-to-surface interface between the exterior surface 44 of the tube fitting 18 and an interior surface 70 of the fuel tank neck tubing. Continuing along the interface sealing path, a second seal 74 can be produced at an interface between the mated first and second screw threads 36, 50. Further, a third seal 76 can be produced at a surface-to-surface interface between the first side surface 31 of the first connector 16 and the second side surface 54 of the tube fitting 18. A fourth seal 78 can be produced at a surface-to-surface interface between the shoulder 37 of the first connector 16 and the side surface 66 of the fuel tank neck tubing 20. Lastly, a fifth seal 80 can be produced at an interface between the threaded self-tapping threads 34 and the exterior surface 68 of the neck tubing 20. Furthermore, not all of the individual seals need be provided in all embodiments; indeed, in one embodiment only the first seal 72 need be produced to provide an effective seal against leakage. All of the seals—if produced in a particular embodiment, and alone or in combination with one another—can altogether, or at least help, prevent escape of liquid fuel, gas fuel, and vapor from the flow passage 60 and from the flow passage 38 to the surrounding environment outside of the first connector 16.
The numerous seals are effectively provided without the use of welding operations, clamping components, or both, which are sometimes included in previously-known connections. Though one or more welds among the components of the connection assembly 10 are possible in some embodiments, in at least one embodiment welds among the components can be eliminated while still securing the components together via threading, for example, and providing sealing via the surface-to-surface confronting contact. Similarly, though one or more sealing members (e.g., o-ring gaskets) among the components of the connection assembly 10 are possible in some embodiments,—such as an o-ring gasket 82 sandwiched between free end 62 and axially-facing side surface 66 and an o-ring gasket 84 sandwiched between the non-threaded section 56 and the interior surface 70, or both, as shown in FIG. 8—in at least one embodiment sealing members need not be provided in the connection assembly while still producing seals via the surface-to-surface confronting contact.
One difference in the second embodiment is a fuel tank vent tubing 182. The fuel tank vent tubing 182 leads to, and communicates with, a venting system component equipped in the accompanying fuel tank. The fuel tank vent tubing 182 can have different designs and constructions depending upon, among other considerations, the design and construction of the venting system and of the fuel tank neck tubing 120. In this embodiment, the fuel tank vent tubing 182 is located radially-inwardly of the fuel tank neck tubing 120, and has an exterior surface 184 that makes surface-to-surface confrontation and abutment with the interior surface 70 of the fuel tank neck tubing. The fuel tank vent tubing 182 can be composed of a metal or a plastic material such as an HDPE or polyamide (PA) material. Like the fuel tank neck tubing 120, the fuel tank vent tubing 182 has a generally elongated cylindrical shape. The fuel tank vent tubing 182 can be placed concentrically inside of the fuel tank neck tubing 120 during the blow molding process of the fuel tank while the neck tubing is still partially molten, and can be secured in-place therein once the material of the fuel tank neck tubing cools and solidifies around it. To assist securement, the fuel tank vent tubing 182 can have several ribs 186 projecting radially-outwardly from the exterior surface 184. The ribs 186 can bond with the material of the fuel tank neck tubing 120 during the blow molding process. The securement between the fuel tank neck tubing 120 and the fuel tank vent tubing 182 might only be temporary, with more permanent securement provided with the assembly and installation of the first and second connectors 116, 118. When assembled and in use, a seal 188 can be produced at a surface-to-surface interface between an interior surface 190 of the fuel tank vent tubing 182 and an exterior surface 144 of the second connector 118.
Furthermore, the vehicle fuel tank connection assembly 10 can have different designs, constructions, and components apart from what is shown in the figures. For example, the location and placement of the first connector 16 and the tube fitting 18 could be swapped in which case the first connector is the most radially-inwardly component and the tube fitting is the most radially-outwardly component; the overlapped axial extent of the tube fitting and fuel tank neck tubing need not necessarily be less than the axial extent of the first connector; and the various side surfaces need not necessarily abuttingly engage when the components are fully assembled and installed.
While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.
