Patent Application
20080107549
The present invention relates generally to fuel pumps and more particularly to fuel pump modules for placement in fuel tanks.
In-tank fuel pump modules are used in automotive fuel delivery systems to draw fuel from a fuel tank and supply the fuel under pressure for delivery to an engine. These modules usually include a fuel reservoir disposed within the fuel tank and carried by a mounting plate or flange closing an opening in an upper wall of the tank. The reservoir holds a relatively small quantity of fuel, and typically includes a reservoir inlet in communication with the interior of the fuel tank.
The module typically includes an electric fuel pump assembly having a pump inlet in one end communicating with the reservoir downstream of the reservoir inlet, and a pump outlet in another end upstream of the reservoir outlet. The fuel pump assembly draws fuel from within the reservoir through the fuel pump inlet and delivers at least a portion of that fuel to the engine through the reservoir outlet. The fuel pump assembly typically includes an electric motor disposed in a motor housing and adapted to be immersed in fuel. The motor includes a rotor mounted for rotation within the motor housing and is connected to a source of electrical power for rotating the rotor. A mechanical pumping element is coupled to the rotor for developing pressure on the fuel.
In fuel pump assemblies of this type, the pumping element discharges fuel into the motor housing to cool the motor as the fuel flows past the motor and out of the pump outlet. While generally effective at cooling the electric motor, pump assemblies of this type undesirably heat the fuel. Such pump assemblies also have resistance to the flow of fuel being pumped through the electric motor portion of the pump assembly. Such windage losses limit the efficiency of such pump assemblies.
Moreover, automobile designers find it increasingly desirable to package fuel tanks in vertically confined spaces such as underneath a rear seat of a vehicle. Therefore, the fuel tank and fuel pump module should be axially as short as possible. But, current fuel pump modules are axially too long to be packaged in such a location. Accordingly, in-tank fuel pump modules are typically modified to accommodate various requirements peculiar to different vehicle applications. But this approach generally requires extensive retooling to provide a compatible design for each separate vehicle application.
A fuel pump and filter assembly is adapted to draw fuel from a fuel tank, filter the fuel, and output the filtered fuel for delivery to an engine. The assembly includes a housing supporting a filter in a filter chamber, which is at least partially defined by first and second end walls, an outer side wall extending therebetween, and an inner side wall disposed radially inwardly of the outer side wall. A fuel pump assembly is carried by the housing radially inwardly of the inner side wall and includes a sleeve that extends from the first to the second end wall of the housing.
Preferably, the fuel pump assembly includes a first end with electrical elements, and a second end with a fuel pump inlet and outlet disposed substantially at the second end. Also preferably, the fuel pump and filter assembly is adapted for use with a fuel pump module, which may also include a fuel pump outlet conduit extending from the fuel pump outlet to a housing inlet, a fuel strainer communicating with the fuel pump inlet, and a fuel pressure regulator communicating with a housing return or outlet.
At least some of the objects, features and advantages that may be achieved by at least certain embodiments of the invention include a fuel pump and filter assembly that is readily adaptable to various fuel pump modules, fuel tanks, and vehicle applications; routes pressurized fuel away from an electric motor portion of the assembly; reduces or eliminates pump flow-through losses; increases fuel pumping efficiency; decreases heat transferred to the fuel before it is discharged from the fuel pump assembly; improves the venting of fuel vapor from the fuel pump; lowers the electric current draw of the fuel pump; eliminates costly seals between a pump and a housing; allows for a reduction in axial height of a fuel pump module compared to prior art designs; enables an electrical connector of a fuel pump assembly to extend out of a fuel tank; eliminates one or more wiring harnesses; and is of relatively simple design, economical manufacture and assembly, rugged, durable, reliable, and in service has a long useful life.
Of course, other objects, features and advantages will be apparent in view of this disclosure to those skilled in the art. Various other fuel pump and filter assemblies and/or fuel pump modules embodying the invention may achieve more or less than the noted objects, features or advantages.
These and other objects, features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments and best mode, appended claims, and accompanying drawings in which:
Referring in more detail to the drawings,
The fuel pump assembly 12 may be any suitable pumping device, such as an electromechanical pumping device, that pressurizes fuel for delivery to an upstream or inlet side of the filter 16. The fuel pump assembly 12 is centrally located with respect to the filter 16 and housing 14 such that the filter 16 and the housing 14 circumscribe the fuel pump assembly 12. The fuel pump assembly 12 has an electric motor 18 with a drive shaft 20 connected to a mechanical fuel pump 22 between inlet and outlet end caps 24, 26, all of which may be carried inside a side wall or sleeve 28 extending axially along the assembly 12.
At a first end 30 of the fuel pump assembly 12, the first end cap 24 may include an electrical connector 34 having electrical elements 36 such as leads, terminal pins, wires, or the like for electrical communication with the motor 18. At a second end 32 of the fuel pump assembly 12, the second end cap 26 may include a fuel pump inlet 38 and a fuel pump outlet 40, such that fuel is drawn into and discharged from the fuel pump assembly 12 substantially at the second end 32 thereof. A similar and exemplary fuel pump of this type is disclosed in U.S. Patent Application Publication 2006/0083631, which is assigned to the assignee hereof and is incorporated herein by reference in its entirety.
Although the inlet 38 and outlet 40 are shown extending through the end cap 26 and in a longitudinal direction, it is also contemplated that the inlet 38 and outlet 40 could be oriented and positioned in any other suitable manner substantially at the second end 32 of the fuel pump assembly 12. For example, the fuel pump assembly 12 could be a side discharge type of unit, wherein an outlet discharges through the side of the fuel pump assembly 12 at the second end 32 thereof. An exemplary fuel pump assembly of this type is disclosed in U.S. Pat. No. 6,231,318, which is assigned to the assignee hereof and is incorporated herein by reference in its entirety. As with the illustrated assembly 10, such an exemplary fuel pump assembly and the housing 14 would be arranged to output pressurized fuel externally with respect to the housing 14.
The fuel pump assembly 12 is carried by and preferably attached to the housing 14 in any suitable manner. For example, as will be discussed in greater detail below, the fuel pump assembly 12 may be welded or press fit to the housing 14. Moreover, the fuel pump assembly 12 may be attached to the housing 14 in any other suitable fashion including use of integral snap-fit fastening features, separate fastening elements, and/or the like.
The housing 14 carries the filter 16 and the fuel pump assembly 12 and at least partially defines a filter chamber 42 for accepting fuel and the filter 16 therein. The filter chamber 42 may be of any suitable shape, such as annular. The housing 14 includes a first end wall 44, an oppositely disposed second end wall 46, an outer side wall 48 extending therebetween, and preferably may also include as an inner side wall, the pump sleeve 28 extending therebetween. The inner side wall 28 is disposed radially inwardly of the outer side wall 48 with a radial space in the form of the filter chamber 42 therebetween. The fuel pump assembly 12 is disposed radially inwardly of the sleeve 28 and, preferably, longitudinally extends between the first and second end walls 44, 46. More preferably, the fuel pump assembly 12 extends beyond portions of the first and second end walls 44, 46 to which the fuel pump assembly 12 is attached. For instance, as shown, the sleeve 28 is attached to, and extends beyond, flared portions of the end walls 44, 46.
As shown, the housing inner side wall doubles as the pump sleeve 28 and supports the fuel pump assembly 12 therein. In other words, the pump assembly 12 and housing 14 preferably share a common side wall 28., which can be a fuel pump sleeve or any other suitable generally hollow and preferably cylindrical component. Preferably, the pump sleeve 28 and the end walls 44, 46 are made of a metal such as steel and the end walls each circumferentially continuously welded at 50 to the sleeve 28. Accordingly, no elastomeric seals are required between the pump assembly 12 and the housing 14. Moreover, this construction enables good heat transfer between the pump assembly 12 and the fuel within the fuel chamber 42 so as to cool the motor 20.
Also, the housing 14 may include a fuel inlet 52 to accept fuel from the fuel pump assembly 12, a fuel return 54 to return fuel to the fuel tank (not shown), and a fuel outlet 56 through which filtered fuel may flow to the engine. Any suitable seals 58 may be disposed in the inlet 52, return 54, and outlet 56, such as elastomeric O-rings.
Additionally, the housing 14 may be of any suitable shape and size. As shown, the housing 14 is generally cylindrical but may be of any other suitable shape. For example, the housing 14 may be spherical or semi-spherical wherein the end and side walls are at least partially integrated. In another example, the housing 14 may be box-like with multiple side walls.
The filter 16 receives fuel incoming through the housing fuel inlet 52 from the fuel pump assembly 12, filters the fuel, and discharges filtered fuel for flow out the housing fuel return 54 and outlet 56. The filter 16 may include a filter element 60, such as of annular shape and corrugated fibrous material, and opposed end caps 62 supporting the filter element 60. For example, the end caps 62 may be of annular shape and may include curled seals 64 that sealingly engage corresponding inside surfaces of the first and second ends 44, 46 of the housing 14. The seals 64 may also be annular and are preferably laterally or radially offset so as to at least partially define an inlet chamber 66 in direct communication with the outside of the filter 16 and an outlet chamber 68 isolated from and downstream of the inlet chamber 66 and in direct communication with the inside of the filter 16 and the outlets 54 and 56. The inlet chamber 66 is defined by outer portions of the filter seals 64, and the outer side wall 48 and end walls 44, 46 of the housing 14. The outlet chamber 68 is defined by inner portions of the filter seals 64, and the inner side wall 28 and end walls 44, 46 of the housing 14. Accordingly, the filter 16 receives incoming fuel from the inlet chamber 66 at its outer surface, filters the fuel flowing therethrough, and releases the filtered fuel from its inner surface into the outlet chamber 68.
The assembly process of the fuel pump and filter assembly 10, and the construction of the components of the assembly 10, may be carried out in any suitable manner, including using automatic or manual assembly, welding, molding, machining, forming, and/or the like. For example, the housing 14 may include a drawn cup defining the second end wall 46 and outer side wall 48, and a stamped cover serving as the first end wall 44. The housing 14 may be composed of any suitable material, but is shown as a metal of any suitable composition such as steel, stainless steel or aluminum. Similarly, the fuel pump assembly sleeve 28 may be formed from a metal component, such as a tube of steel, stainless steel or aluminum, and may be supported by the housing 14 in any suitable fashion. However, the housing 14 and sleeve 28 may be molded of suitable plastic and heat or fusion welded together.
The metal sleeve 28 may be circumferentially continuously attached to the metal first end wall 44 of the housing 14, such as by laser welding, friction welding, or the like. Then, the filter components 60, 62 may be provided as a finished sub-assembly filter 16 or may be pre-assembled together just prior to assembly into the housing 14 around the sleeve 28. Next, the metal drawn housing portion including the second end wall 46 and outer side wall 48 may be assembled over the filter 16 and metal sleeve 28 to the metal first end wall 44 of the housing 14.
Thereafter, the outer side wall 28 of the housing 14 can be circumferentially continuously attached to the first end wall 44 of the housing 14, while the second end wall 46 of the housing 14 is circumferentially continuously attached to the sleeve 28, such as by laser or friction welding or the like. Subsequently, the components of the fuel pump assembly 12, such as the first end cap 24, the motor 18, the driveshaft 20, the pump 22, and the second end cap 26 can be assembled into the sleeve 28. Finally, the ends of the sleeve 28 are rolled over to project radially inward of outer surfaces of the end caps 24, 26 to generally align and hold the assembly 12 together and prevent de-coupling of the pump 22 from the motor 18.
Alternatively, the pump components could be assembled in the sleeve 28, the ends rolled over and then this assembly inserted into the housing 14 and welded therein.
The various components of the fuel pump and filter assembly 10 may be composed of any suitable materials, such as metals, composites, polymeric materials, and the like. Such materials can be selected based on their dimensional stability and resistance to swelling and degradation in warm and cold petroleum product environments. The phrase polymeric materials generally means relatively high-molecular-weight materials of either synthetic or natural origin and may include thermosets, thermoplastics, and elastomers.
In operation, electricity may be provided to the motor 18 from any suitable source to power the motor 18 and, thus, drive the pump 22. While driven, the pump 22 draws fuel through its fuel inlet 38, pressurizes the drawn fuel, and discharges the pressurized fuel through the fuel outlet 40. Any suitable conduit (not shown) may be used to deliver the pressurized fuel from the pump 22 through the housing inlet 52 to the inlet chamber 66 at the upstream side of the filter chamber 42. Under pressure, the fuel flows into the filter 16 through its outer surface, through the filter 16, and out of the filter 16 through its inner surface. From the filter 16, the fuel flows into the outlet chamber 68 at the downstream side of the filter chamber 42. The filtered pressurized fuel then flows out of the housing 14 through the fuel return 54 and outlet 56.
In any case, providing the inlet 38 and outlet 40 substantially at one end of the pump assembly 12, eliminates substantial flow of fuel through the motor chamber 70 in which the motor 18 resides within the sleeve 28. This construction thus reduces resistance to turning of the motor 18 to reduce windage losses and excessive heating of the fuel. It is, however, contemplated that some fuel may leak or otherwise flow into the motor chamber 70, such as along the shaft 20 or through a vapor purge port (not shown) of the pump 22. Nonetheless, this relatively small amount of fuel may be used to cool the motor 18, and may vaporize or may drain out of the motor chamber 70 back into the fuel tank (not shown) through one or more small channels (not shown) provided between the sleeve 28 and the other pump components. For example, such channels could be provided in any suitable location, such as between the outer diameters of the pump 22 and second outlet cover 26 and the inner diameter of the pump sleeve or housing inner wall 28.
Accordingly, in normal operation, the motor chamber 18 is preferably not completely filled with liquid fuel and the centrifugal force imparted to the liquid fuel by the spinning rotor of the motor 18 moves the fuel generally radially outwardly. This provides a vapor barrier adjacent the motor 18 as the heavier liquid fuel is forced outwardly away from the motor 18 within the housing 14. It is also presently believed that the vapor barrier surrounding the motor 18 further reduces the resistance to rotation of the motor 18 which decreases the electric current draw of the motor 18 and increases the efficiency of the fuel pump assembly 12. Also, the reduced pressure in the motor chamber 70 is believed to increase the amount of fuel vapor in the motor chamber 70, reducing resistance to rotation of the motor 18. Still further, less heat is transferred to the fuel delivered to the engine (not shown) as it passes through the fuel pump assembly 12 from the inlet 38, through the pump 22, and out the outlet 40. Desirably, this may reduce fuel vapor formation in the fuel delivered to the engine and may also reduce fuel vapor formation in the fuel tank.
The fuel pump and filter assembly 10 may be used as a stand alone product or may be incorporated in a fuel pump module for use in a fuel tank. More particularly,
The fuel pump and filter assembly 110 may include the same fuel pump assembly 12 and the filter 16 as described with respect to
Unlike the construction of
The fuel pump module 100 may also include various components in fluid communication with the fuel pump and filter assembly 110. For example, a pump outlet conduit 172 can be provided between the fuel pump outlet 40 and a housing inlet 152, and may include a system check valve 174 therein to prevent reverse flow of fuel from the fuel filter chamber 42 back into the fuel pump assembly 12. Also, a fuel strainer 176 may communicate with the fuel pump inlet 38 to filter incoming fuel from the fuel tank. Further, a regulator 178 may communicate with a housing fuel return 154 to regulate the pressure of fuel output of the module 100. Finally, an outlet conduit 180 may communicate with a housing fuel outlet 156, such as with a quick-connect endform fitting, to deliver fuel from the module 100.
The unique configuration of the fuel pump and filter assembly 110 enables it to be attached to a fuel tank F and extend out of the fuel tank F. More particularly, the mounting flange 144 enables the module 100 to be suspended from a wall T of the fuel tank F such as a tank upper wall. This was not possible with a typical conventional fuel pump module because pressure within the motor chamber would force fuel vapors out of the first end of the fuel pump assembly and into the atmosphere.
But with the present fuel pump and filter assemblies 10, 110, a substantial amount of liquid fuel is not pumped through the motor chamber 70, and the motor chamber 70 is vented through the second end 32 of the fuel pump assembly 12 to the inside of the surrounding fuel tank F to permit any fuel vapor to be discharged into the fuel tank F. In other words, the first end 30 of the fuel pump assembly 12 does not vent fuel vapors therethrough and does not have a significant pressure differential across it. Accordingly, the first end 30 of the fuel pump assembly 12 may extend out of the fuel tank F as shown in
In addition to the fuel pump and filter assembly 110, the module 200 includes the pump outlet conduit 172 and check valve 174 to deliver fuel from the fuel pump assembly 12 to the housing 114, and the strainer 176 to filter fuel coming into the fuel pump assembly 12. Additionally, the module 200 includes a reservoir casing 282.
The reservoir casing or can 282 includes side walls 284 that relatively overlap a lower peripheral portion of the pump and filter housing 114. The module 200 may also include a fuel pressure regulator 278 in communication with the housing return 154 such as by any suitable conduit like a hose or a rigid passage integrally formed with the reservoir casing 282 and a jet pump 286 actuated by fuel bypassed by the pressure regulator 278. The jet pump 286 is a reservoir-filling device that draws fuel into the reservoir casing 282 from the fuel tank F through a reservoir inlet and an inlet check valve (not shown), which prevents fuel from exiting the reservoir casing 282 through the reservoir inlet. The fuel pressure regulator 278 is supported by the reservoir casing 282 and is in fluid communication with the housing return 154 to limit fuel pump output pressure by metering a portion of high-pressure fuel from the housing return 154 back into the reservoir casing 282 and/or the fuel tank F.
The reservoir casing 282 may be movably carried by the fuel pump and filter assembly 110, or it may be fixed or attached thereto, in any suitable manner including using any suitable guides and/or fixing devices 283. The reservoir casing 282 may be freely bottom referenced against a bottom wall B of the fuel tank F, or fixed to the bottom wall B of the fuel tank F, such as by any suitable interconnection element or feature 285, which may include one or more buttons, dovetails, snap fasteners, clamps or the like.
The module 300 includes an upper assembly 302 adapted for mounting to a wall of a fuel tank (not shown) and a lower assembly 304 suspended from the upper assembly 302 by slidably engaging posts 306, 308. The upper assembly 302 may be a mounting flange with suitable electrical and fluid connectors.
As shown in
The housing 382 may be molded of a plastic material and includes several integrally molded features. For example, an integrally molded pump outlet conduit 376 is provided in fluid communication between the fuel pump assembly 12 and the housing inlet 52. For injection molding feasibility, the conduit 376 is manufactured to be open at one end but is closed by a plug 377 assembled therein. Also, a supply side jet pump 386 includes an integrally molded supply conduit 387 connected to the return 54, an exemplary laser-drilled jet nozzle 388 in communication with the conduit 387, and an anti-siphon check valve 390 to prevent reverse flow of fuel from the can 383 into the housing 14 through the return 54. The jet nozzle 388 is oriented toward an integrally molded, exemplary venturi or ejector tube 392 in communication between the interior of the fuel tank (not shown) and the reservoir interior. The tube 392 also provides a standpipe which retains fuel in the reservoir when the module is not operating and the level of fuel in the tank is below the upper end of the tube 392. While the tube 392 preferably has a tapered inlet and outlet, it can be a tube with a uniform diameter throughout its length.
As shown in
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.
