Fluid handling – Systems – With pump
Reexamination Certificate
1997-08-29
2001-08-14
Rivell, John (Department: 3753)
Fluid handling
Systems
With pump
C137S574000, C137S576000, C123S514000
Reexamination Certificate
active
06273131
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for conveying fuel from a fuel tank to the internal combustion engine of a motor vehicle having a conveying unit communicating on the intake side with the fuel tank and on the pressurized side with the engine, and a return line which leads to a jet pump, located near a tank bottom, that pumps the excess fuel via a mixing region into a reserve pot, from which the conveying unit draws fuel.
2. Prior Art
In conveying devices in accordance with German Patent Disclosure DE 42 24 981 A1, with the aid of the jet pump an adequate filling of a reserve pot is to be assured, in which reserve pot the conveying unit is disposed and from which the fuel is fed to the engine. This is intended to assure a fuel reserve for the conveying unit even if the fuel tank is relatively empty, and this reserve assures that even relatively long hill uphill grades, for instance, can be overcome without problems. To fill the reserve pot, in the lower region near the tank bottom a mixing region is provided, by which both fresh fuel from the fuel tank and fuel returning from the engine are delivered to the reserve pot via an aspirating jet pump. In the mixing region near the jet pump, an opening is provided by way of which fresh fuel can enter the mixing region. To prevent the reserve pot from running empty once the engine and hence the conveying unit have been shutoff, this opening has a closing element in the form of a flap or valve plate, which opens whenever the engine is in operation and the jet pump is introducing returned fuel into the mixing region. However, this arrangement has the disadvantage of a complicated arrangement for closing the opening, which moreover requires a large amount of space. In addition, such closing elements, which are located at the inlet to the mixing region, cannot close the opening tightly, so that especially when the engine has been off for some time while the vehicle is parked on a slope, starting is impossible.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved device for conveying fuel from a fuel tank to an internal combustion engine of a motor vehicle, which does not suffer from the above-described disadvantages.
This object and others which will be made more apparent hereinafter are attained in a device for conveying fuel from a fuel tank to the internal combustion engine of a motor vehicle having a conveying unit communicating on the intake side with the fuel tank and on the pressurized side with the engine, and a return line which leads to a jet pump, located near a tank bottom, that pumps the excess fuel via a mixing region into a reserve pot, from which the conveying unit draws fuel.
According to the invention a siphon-like mixing region is provided between the reserve pot and the tank bottom and the siphon-like mixing region is provided with an opening into the reserve pot in a transitional region The opening extends parallel to the tank bottom and is closable with a closing element that is axially movable relative to the opening.
The conveying device according to the invention has the advantage over the prior art of enabling a simple, economical arrangement which enables secure closing of the mixing region with regard to the reserve pot. Shallow installation can moreover be attained as a result, so that in addition a greater tank volume can be made available for holding fuel. Further, because of the siphon-like embodiment of the mixing region, it can be assured that complete evacuation of the reserve pot can be prevented. Thus at least a minimum amount of fuel remains in the reserve pot, and the level of the fuel remaining in the reserve pot can be determined by the size of the siphon-like mixing region.
In a further embodiment of the invention it is provided that a filter element is disposed in the opening in the transitional region. As a result, the dirt entrained with the fresh fuel can be trapped, so that only filtered fuel can reach the reserve pot. This has the advantage that plugging up of the prefilter by the conveying unit can be prevented, and the conveying unit can have a longer service life.
In another advantageous embodiment of the invention, it is provided that the opening in the transitional region has a sealing face. This allows simplification of production and a reduction in the number of components. The closing element can thus rest directly on the sealing face and reliably close the reserve pot and protect it against running empty. Advantageously, the sealing face or sealing element is integrated into the transitional region.
In another advantageous embodiment of the invention, it is provided that the filter element is embodied integrally with the opening, and that the closing element can be disposed in the filter element so as to be axially movable relative to the opening. As a result of this arrangement, the number of components can be reduced further, which also enables cost savings by simplifying assembly. The closing element can simply be inserted into the filter element and fixed relative to the filter element by a clip connection with a plug, so that fast and simple embodiment and assembly can be provided.
In another advantageous embodiment of the invention, it is provided that the opening in the transitional region is closable with a spherical closing element and can be disposed in a cage-like filter element toward the opening. This alternative feature, in comparison with the closing element described above, has the additional advantage of allowing simple, economical design. The cage-like filter element can assume a dual function. First, it secures the positioning of the spherical closing element relative to the opening. Second, the filter element can trap the dirt entrained by the fuel flowing into the reserve pot.
In another advantageous embodiment of the invention, it is provided that a lower edge of the reserve pot is embodied as no higher than a lower edge of the mixing region. As a result it can be assured that the initial filling quantity can flow into the reserve pot.
Advantageous further embodiments of and improvements to the main claim are recited in the further dependent claims.
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patent: 4842006 (1989-06-01), Scheurenbrand et al.
patent: 5080077 (1992-01-01), Sawert et al.
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patent: 41 23 367 A1 (1993-01-01), None
patent: 422498A1 (1994-02-01), None
patent: 2602234 (1997-04-01), None
Rivell John
Robert & Bosch GmbH
Striker Michael J.
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