Fluid handling – Systems – With pump
Reexamination Certificate
2001-06-06
2003-11-04
Lee, Kevin (Department: 3753)
Fluid handling
Systems
With pump
C137S571000, C210S232000, C210S416400
Reexamination Certificate
active
06640832
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a fuel delivery unit, for example for supplying fuel to an internal combustion engine, such as the engine of a motor vehicle.
A typical form of a fuel delivery unit for such purposes comprises an installation holder which is operable to brace the arrangement in relation to the bottom of a fuel tank, for example by means of compression springs or flexible damping elements. It has at least one reservoir with a fuel pump disposed therein, optionally a fuel filter, and a cover closure for closing a fitting opening in the fuel tank into which the unit is fitted. Such a fuel delivery unit can be found for example in EP 0 203 244, EP 0 297 256 and for example DE 196 15 081.
Those fuel delivery units are intended to be so designed that they can be fitted and removed as a combined assembly comprising a reservoir or surge or swirl pot, a fuel pump, a fuel filter and the cover closure for the tank fitting opening, and in addition can be securely fixed on the bottom of the fuel tank. On the one hand, the aim is to ensure that the entire unit call be quickly and reliably changed in a repair or maintenance situation, while on the other hand the aim is also that such units can be adapted to any heightwise tolerances in regard to the fuel tanks used. In that respect, there have been various proposals directed at so designing the delivery unit that heightwise tolerances can be compensated by axial displaceability at least of the fuel pump, preferably the surge pot with the fuel pump disposed therein, in relation to the cover closure or a cover flange forming part of the fuel tank. For example above-mentioned EP 0 297 256 provides that the electrically powered fuel pump is designed to be axially slidable by way of a telescopic guide arrangement, with the pressure feed and return conduits, with in addition measures for supporting the fuel pump in such a way as to insulate the assembly in regard to noise.
It will be noted however that modern fuel tanks are often of such a configuration as to involve a large number of branches and other ramifications and thus afford little flat area for accommodating cover closures, cover flanges or the like, as well as also affording only limited installation volumes for fitting therein a fuel delivery unit. This means that a major demand in terms of a fuel delivery unit is for it to he as compact as possible. On the other hand however it is also necessary to ensure that the reservoir which forms part of the fuel delivery unit and which can act as a surge or swirl pot can afford an adequate volume of fuel for the fuel pump so that, even when the motor vehicle in which the tank is fitted is negotiating a bend or when the vehicle is accelerating, the engine is guaranteed a proper regular supply of fuel thereto. Finally, the volume of fuel in the reservoir often serves as a reserve of fuel. In that case, when the tank is completely emptied, the system either switches over from one or more main fuel gauges or level indicators in the fuel tank to a reserve fuel level or secondary fuel level indicator in the reservoir, in order to afford a display of maximum accuracy of the reserve amount of fuel, based on the defined volume afforded by the reservoir. The demand for the reservoir to be of the largest possible volume is however in conflict with the requirement that the fuel delivery unit is to be as compact as possible and of small dimensions so that the fitting opening for introducing the fuel delivery unit into the fuel tank in which it is to be fitted can be as small as possible. Furthermore, because of the problems in relation to sealing integrity which are related to this consideration, the fitting opening in the fuel tank should not exceed a given size.
This problem is already addressed for example in DE 32 25 929. In that arrangement the reservoir or the swirl or surge pot is made from a plurality of parts which can be secured together by a latching engagement in their position of installation on the bottom of the tank. In that case one of the parts of the swirl or surge pot forms a holder for a fuel delivery assembly which is to be subsequently inserted and which is to be installed at an angle relative to the bottom of the fuel tank in order to be able to use this arrangement even in a tank which is of relatively small structural height. However, it is not readily possible to adopt that design configuration for the reservoir in the case of a fuel delivery unit of the above-indicated kind, but rather it requires fitment of the individual parts of the reservoir and the fuel delivery assembly in a given sequence.
Reference may also be made to DE 195 28 182 disclosing a fuel delivery unit with a fuel level indicator, for installation in a fuel tank, in which a holder for accommodating a fuel delivery assembly is arranged on a tank flange in such a way as to be longitudinally slidable and rotatable. This design configuration provides that a lower end of the holder of the fuel delivery assembly can be pivotably centered on the bottom of the fuel tank or a surge or swirl pot so that an angular deviation of the flange and/or the bottom of the fuel tank from a reference position cannot have an effect on the measurement accuracy of a fuel level pick-up disposed on the fuel delivery unit. That design arrangement involves a comparatively large reservoir which accommodates the fuel pump and, with a fuel filter in a filter housing, is arranged rotatably and pivotably therewith, forming a fitting unit, by way of spring elements. Fitment of the fuel delivery unit is effected in a configuration which approximately corresponds to the installation position thereof. That arrangement of the individual parts relative to each other also requires a comparatively large fitting opening in the tank which, as already indicated above, is often undesirable.
EP 0 922 603 A1 sets forth an arrangement of two fuel reservoirs for being accommodated in a fuel tank, which are flexibly connected together at one side and at the bottom, more specifically by way of flexible bars which in a fitment configuration permit the reservoirs to assume an angled relationship with each other. The reservoir which is to be introduced first into the tank is fitted in a tilted position into the fitting opening of the tank, in such a manner that its upper end is firstly directed transversely with respect to the bottom of the tank. In order to arrange that reservoir in the installation position thereof, the first reservoir has to be turned through 90° in the tank when the second or main reservoir is being introduced into the fitting opening of the tank, in which case the main reservoir must be tilted in the fitting opening in the tank. This means that the operation of introducing that arrangement into the tank is extremely complicated and time-consuming. Ultimately, the fact that the reservoir which is to be introduced last into the tank must be tilted upon pivotal movement of the reservoir which is first inserted into the tank means that it is necessary for the internal width of the fitting opening to be selected of a correspondingly large size, which basically is something that is not wanted, as already indicated above.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a fuel delivery unit which is so designed that it always affords a sufficiently large delivery volume for a fuel pump while nonetheless being so compact that the fitting opening for same in the fuel tank can still be comparatively small.
Another object of the present invention is to provide a fuel delivery unit which affords enhanced versatility in terms of fitting it into a fuel tank to make the fitting operation easier to implement.
Still another object of the present invention is to provide a fuel delivery unit which while being of a simple structure call afford the possibility of structural re-configuring thereof for greater ease of fitting it into a motor vehicle fuel tank.
In accordance with the principles of the present invention the foregoing and other objects are
Akin Gump Strauss Hauer & Feld L.L.P.
Kautex Textron GmbH & Co. KG
Lee Kevin
LandOfFree
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