Pumps – Diverse pumps
Reexamination Certificate
1999-10-04
2001-04-10
Walberg, Teresa (Department: 3742)
Pumps
Diverse pumps
Reexamination Certificate
active
06213726
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to a vehicle fuel delivery system and more particularly to a fuel pump module constructed to be disposed within a vehicle fuel tank.
BACKGROUND OF THE INVENTION
Some fuel delivery systems utilize an electric fuel pump disposed within a vehicle fuel tank to draw fuel from the fuel tank and deliver that fuel under pressure to the vehicles engine. Contaminants within the fuel tank, such as weld slag or other residual materials from the manufacturing of the fuel tank as well as contaminants added to the tank during its use, can damage the fuel pump if allowed to enter therein and severely effect the durability and reliability of the fuel pump. To prevent at least the most harmful contaminants from entering the fuel pump, fuel filters of various materials have been disposed adjacent to the fuel pump inlet to trap these contaminants. These fuel filters are generally relatively small in size and located directly adjacent and attached to the fuel pump inlet.
In use, fuel flows in one direction through the fuel filter and the contaminants trapped by the filter clog the pores of the filter material and thereby reduce the fuel flow through the filter. The reduced fuel flow through the filter and into the fuel pump can damage the fuel pump as its strains to draw sufficient fuel through its inlet to supply a sufficient amount of fuel to the vehicle engine. In extreme cases, the fuel filter can become so clogged that insufficient fuel is delivered to the engine severely affecting the performance of the engine.
In addition, increasingly strict governmental regulations are being imposed which limit the allowable escape to the atmosphere of hazardous hydrocarbon fuel vapors. In response to these regulations, many fuel delivery systems for internal combustion engines, such as for automobiles have incorporated fuel vapor management systems including fuel vapor collection canisters disposed some distance from the fuel tank and in communication with a vapor dome in the fuel tank through a vapor vent valve. In at least some of these fuel vapor management systems, a pressure drop created by the operating engine is used to purge fuel vapors from the carbon canister by drawing fuel vapor from the canister into an intake manifold of the engine for combustion within the engine. Thus, carbon canisters have been mounted away from the fuel tank and closer to the vehicle engine to facilitate purging of the fuel vapor from the carbon canister.
SUMMARY OF THE INVENTION
A fuel pump module disposed within a vehicle fuel tank has a fuel pump therein to draw fuel and deliver that fuel under pressure to the vehicle engine, and a secondary low pressure source to lower the pressure within the module to draw fuel from the fuel tank through a filter of the module when the fuel pump and/or the vehicle engine is operating. When the fuel pump and vehicle engine are not operating, such as when the vehicle is not is use, the secondary low pressure source is terminated and the pressure within the module returns to that of the fuel tank. When the level of fuel in the fuel tank is lower than that within the fuel pump module, a portion of the fuel within the module returns to the fuel tank through the filter of the module thereby dislodging at least some of the contaminants trapped by the filter.
In one form, the module further has a float valve to control the escape of fuel vapor from the module and to prevent the escape of liquid fuel therethrough. Desirably, by venting the fuel pump module to an intake manifold of the vehicle engine or to a carbon fuel vapor collection canister mounted exteriorly of the fuel pump module, the pressure within the fuel pump module is at or near atmospheric pressure when the valve is opened. When disposed within a fuel tank maintained at least slightly above atmospheric pressure, fuel will enter the lower pressure fuel pump module through the filter to fill the module. Alternatively, an engine vacuum signal may be applied to the module to remove fuel vapors from the module and to lower the pressure within the module to draw fuel therein from the surrounding fuel tank.
Desirably, the fuel pump module has an inner cup shaped housing in which the fuel pump is received. The inner housing has a valve which permits liquid fuel to be drawn from the surrounding module into the fuel pump and which prevents the reverse flow of liquid fuel from the inner housing to the outer surrounding fuel module. In use, the pressure drop created by the fuel pump draws fuel into the inner housing from the surrounding module and when the fuel pump operation is terminated, a supply of fuel is maintained within the inner housing to be readily available to the fuel pump when it is restarted. A jet pump may be added within the inner housing and operated by fuel in the fuel pump to further lower the pressure within the inner housing for the purpose of drawing fuel from the module into the inner housing. The fuel pump module filter is preferably generally annular and is carried by a cartridge body to define a lower portion of the module and to provide a large surface area fuel filter with an increased life and to permit fuel within the module to flow back into the fuel tank when the pressure differential between the module and the fuel tank and their corresponding fuel levels permit.
Objects, features and advantages of this invention include providing an improved fuel pump module that extends the useful life of a fuel filter, provides increased fuel filter surface area, improves filtration of fuel, dislodges contaminants from the fuel filter in use, maintains a supply of fuel adjacent the fuel pump inlet even during extremely low level fuel level conditions in the fuel tank, extends the service life of the fuel pump, permits fuel vapors to escape from the fuel pump module, maintains an increased fuel level in the fuel pump module compared to the fuel tank, provides a reduced pressure in the fuel pump module when the vehicle engine is operating, may utilize an engine vacuum signal to draw fuel into the fuel pump module, is durable, reliable, of relatively simple design and economical manufacture and assembly, and has a long useful life in service.
REFERENCES:
patent: 3575296 (1971-04-01), Peterson
patent: 4190532 (1980-02-01), Halbfoster
patent: 5392750 (1995-02-01), Laue et al.
patent: 5564396 (1996-10-01), Kleppner et al.
patent: 5699773 (1997-12-01), Kleppner et al.
patent: 5779900 (1998-07-01), Holm et al.
patent: 5860796 (1999-01-01), Clausen
Reising Ethington, Barnes, Kisselle, Learman & McCulloch, P.C.
Robinson Daniel
Walberg Teresa
Walbro Corporation
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