Internal-combustion engines – Charge forming device – With fuel pump
Reexamination Certificate
1999-07-26
2001-02-27
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
With fuel pump
C137S565240, C137S558000
Reexamination Certificate
active
06192869
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns a fuel tank, for example for a motor vehicle, and more especially a fuel tank having a filling level measuring device.
BACKGROUND OF THE INVENTION
A typical form of fuel tank, for example for a motor vehicle, comprises a tank body and a fuel conveyor or delivery unit which is arranged within the tank body. The delivery unit has an electric fuel pump by which fuel in the tank can be supplied to the engine of the motor vehicle. In such an arrangement the reservoir whose volume is substantially smaller than that of the fuel tank as a whole is to ensure in particular the function that, even under adverse operating conditions, for example when the motor vehicle in which the tank is fitted is negotiating a bend of considerable length or when the vehicle is not in a horizontal position, there is always a sufficient amount of fuel still in the region of the intake of the fuel pump so that the pump can still draw enough fuel and thus prevent the engine from suffering from fuel starvation. That presupposes the existence of a certain minimum amount of fuel in the reservoir and thus also presupposes that the reservoir itself is of a corresponding minimum volume.
In many cases, the tanks used comprise a thermoplastic material and they can preferably be formed in one piece by an extrusion blow molding procedure. In such a situation the delivery unit with the reservoir is frequently fitted into the tank body after production of the tank body, through an opening which is generally subsequently formed in the wall of the tank after manufacture thereof. As, for reasons of strength and stability and also sealing integrity in respect of the opening which is to be closed after the delivery unit has been fitted in the tank body, it is desirable for that opening to be kept as small as possible, a typical tank of such a configuration suffers from the disadvantage that the reservoir of the fuel delivery unit which is introduced into the tank body through the opening is of a correspondingly small volume which for example is of the order of magnitude of between 0.5 and 1 liter. In many cases, having regard to the duration of the above-mentioned adverse operating conditions which may occur in a practical context and during which only little or no fuel flows into the reservoir from the tank volume surrounding the reservoir, the above-mentioned small volume of the reservoir of the delivery unit is excessively small and thus inadequate for its intended purpose.
It will be noted here that under some circumstances the above-mentioned volume of the reservoir, which is small in any case for the reasons indicated above, may also be further reduced by virtue of the provision of a filling level measuring device which is mounted to the delivery unit on the outside thereof, for measuring the level of fuel in the main body of the tank which surrounds the reservoir. The filling level measuring device thus has to be introduced into the tank through the opening in the tank wall, jointly with the delivery unit. As the cross-section of the opening determines the available contour of the delivery unit and the measuring device may therefore not project outwardly substantially beyond that contour, it thus becomes necessary for the measuring device to be disposed within the contour of the delivery unit, that is to say, within the cross-sectional configuration thereof. That has the inevitable consequence that the volume of the reservoir is correspondingly reduced. Accordingly, the volume of the reservoir is still further smaller than the magnitude which is in any case predetermined by the cross-section of the opening in the wall of the tank body.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a fuel tank which has a fuel reservoir therein, wherein the fuel tank is of such a configuration that the inclusion of a filling level measuring device does not necessarily result in a reduction in the volume of the reservoir.
Another object of the present invention is to provide a fuel tank having a filling level measuring device of such a configuration and arrangement that it also permits the inclusion of a reservoir whose cross-section can be enlarged within the tank perpendicularly to the longitudinal axis of the opening in the wall of the tank body without the reservoir and the filling level measuring device impeding each other.
Still a further object of the present invention is to provide a fuel tank for example for a motor vehicle which includes a reservoir for forming a reserve of fuel to prevent fuel starvation and a fuel level measuring device within the tank, wherein the tank and its related components can be readily assembled in a simple operating procedure.
Yet a further object of the present invention is to provide a fuel tank which includes a fuel reservoir and a fuel level measuring device, wherein the reservoir and the fuel level measuring device can be readily incorporated in the tank and securely held therein.
In accordance with the principles of the present invention the foregoing and other objects are attained by a fuel tank, for example for a motor vehicle, comprising a tank body and a delivery unit which is arranged within the tank body. The delivery unit includes a reservoir for constituting a reserve supply of fuel and can be introduced into the tank body through a closable opening in the wall thereof. The tank further includes a filling level measuring means arranged outside the reservoir in the tank, for measuring the level of fuel in the tank body. The measuring means can also be introduced into the tank body through the closable opening in the wall thereof and it is held in its operative position by a holding means. The filling level measuring means can be introduced into the tank body separately from the delivery unit and is held in its operative position by the holding means which is mounted at the closable opening in the tank wall.
As will be appreciated in greater detail from the description hereinafter of a preferred embodiment of the invention, the fact that the measuring means is separate from the delivery unit and can be introduced into the tank body separately from the delivery unit makes it possible for the two components, that is to say the delivery unit and the filling level measuring means, including the holding means for the latter, to be introduced into the tank body in succession and thus independently of each other, so that they can each be successively put into their respective operative position in the tank body. In that respect the arrangement according to the invention involves fewer limitations in terms of configuration and positioning and also the movements which are possibly to be performed by the fuel level measuring means in dependence on a variation in the level of fuel within the tank, than is the case when the measuring means is mounted to the delivery unit.
In a preferred feature of the invention, the holding means for mounting the filling level measuring means to the tank body is in the form of a ring mounted to the edge of the closable opening in the wall of the tank body. In that respect, it is possible for the measuring means to be mounted transversely with respect to the longitudinal axis of the opening in the tank wall at a spacing from the periphery of the opening. For that purpose it is only necessary for the holding means in the form of the ring for mounting the measuring means to be provided with at least one holding arm or the like holding portion, which extends for example substantially perpendicularly to the longitudinal axis of the opening in the tank body wall and which carries the fuel level measuring means at a spacing from the holding ring. That affords the possibility of the fuel level measuring means being positioned so far from the opening and thus the delivery unit which is introduced into the tank body through the opening that the reservoir can be expanded within the tank body to afford a larger volume in respect thereof, without the fuel level measuring means being in the way.
Hahner Rainer
Puempel Andreas G. R.
Savoni Lou
Siekmann Jim
Wagner Axel
Kautex Textron GmbH & Co. KG.
Miller Carl S.
Seidel Gonda Lavorgna & Monaco, PC
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