Internal-combustion engines – Charge forming device – With fuel pump
Reexamination Certificate
1999-08-20
2001-07-31
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
With fuel pump
C123S510000
Reexamination Certificate
active
06267103
ABSTRACT:
FIELD OF INVENTION
The invention relates to a delivery unit for delivering fuel from a fuel tank to an internal combustion engine of a motor vehicle, having a fuel pump which can be inserted into the fuel tank and is fastened on a retaining part by a pump-retaining means.
BACKGROUND OF THE INVENTION
Fuel delivery units are frequently used in modern motor vehicles and are known in practice. In the case of the known delivery unit, a retaining part has a joint pot-like housing for a fuel filter and the delivery pump. The pump-retaining means is configured as a housing cover which is welded or adhesively bonded to the housing. This configuration has the advantage that the delivery unit is of very compact construction and can easily be put together to give a unit which can be preassembled.
The disadvantage with the known delivery unit, however, is that it is no longer possible for the fuel pump to be replaced once the delivery unit has been assembled. This means that the entire delivery unit is rendered unusable, for example, in the case of a defect in the fuel pump. Furthermore, the configuration does not allow the preassembled delivery unit to be combined subsequently with a fuel pump which is adapted to the envisaged application area. In particular in the case of a series production of delivery units for different motor vehicles with different fuel pumps, this results in very high storage costs.
Thus there is a need to configure a fuel delivery unit such that it is of particularly straightforward construction and that the fuel pump can be exchanged once the delivery unit has been assembled.
SUMMARY OF THE INVENTION
This problem is solved according to the invention in that the pump-retaining means is fastened releasably on the outside of the retaining part and is configured for bracing the fuel pump with the retaining part.
This configuration allows the fuel pump to be fitted in a final operation once the delivery unit has been assembled. The delivery unit and the fuel pump may thus be combined separately in accordance with the respective application area. In addition, it is possible for the fuel pump to be exchanged very easily in the case of a defect. By virtue of the fuel pump being braced with the pump-retaining means and the retaining part, there is no need for any fastening means which involve high outlay as far as fitting is concerned. The delivery unit is thus of particularly straightforward construction.
The assembly of the delivery unit according to the invention is particularly straightforward, and may additionally be automated, if the pump-retaining means is clipped to the retaining part.
According to another advantageous development of the invention, the connection of the fuel pump is particularly straightforward in design terms if an outlet stub of the fuel pump is prestressed against a connection of a fuel line, said connection being arranged on the retaining part.
According to another advantageous development of the invention, the fuel pump can be fitted in a particularly straightforward manner if it is arranged between the connection of the fuel line and the pump-retaining means. The fuel pump is consequently prestressed against the connection by the pump-retaining means, with the result that, at the same time as it is fitted, the fuel pump is connected to the fuel line leading away from it.
According to another advantageous development of the invention, the fuel pump is retained in a positively locking manner in the axial and radial directions once it has been fitted if the connection of the fuel line is configured such that it grips over the outlet stub. This results in the assembly of the delivery unit according to the invention being simplified further.
According to another advantageous development of the invention, the outlet stub is sealed with respect to the connection when the fuel pump is fitted if, in its region which borders the connection of the fuel line, the outlet stub has a sealing element. This means that there is no need for any hoses with hose clamps or the like to be fitted in order to connect the fuel pump. In addition, in the case of an elastic configuration of the sealing element, there is compensation for tolerances of the outlet stub and of the connection of the fuel line in the axial direction and/or radial direction. Furthermore, the sealing element damps the transmission of structure-borne sound of the fuel pump to the retaining part, with the result that the delivery unit according to the invention has a particularly low level of noise emission.
According to another advantageous development of the invention, electrical contact is made with the fuel pump as it is fitted if electric cables leading to the fuel pump have pairs of plug-in contacts which are aligned parallel to the direction in which the pump-retaining means is prestressed against the retaining part and are arranged on the fuel pump and the retaining part. This configuration results in a lot of time being saved when the fuel pump is fitted on the retaining part.
The delivery unit according to the invention is a particularly compact construction if, in a region which is directed toward the fuel pump, the retaining part has a filter housing for a fuel filter. In this case, in dependence on the configuration of the fuel tank, the filter housing may be arranged, for example, above the fuel pump.
According to another advantageous development of the invention, fuel-pump noise is damped by the fuel filter if the filter housing is configured such that it encloses the fuel pump. Furthermore, this configuration means that the filter housing, while requiring just a particularly small amount of installation space, has a large volume.
According to another advantageous development of the invention, the fuel pump is secured against rotation once it has been fitted if a radially projecting prefilter which is fastened on the fuel pump is connected in a positively locking manner to the pump-retaining means.
According to another advantageous development of the invention, the manner in which the fuel pump is prestressed against the retaining part is particularly straightforward in design terms if the pump-retaining means has a plurality of resilient elements distributed over the circumference. In addition, these resilient elements compensate for tolerances of the fuel pump and of the retaining part.
According to another advantageous development of the invention, the weight of the fuel pump need not be supported by the pump-retaining means if the pump-retaining means is arranged above the fuel pump.
If, according to another advantageous development of the invention, the pump-retaining means has guide elements for the fuel pump, this helps to secure the fuel pump particularly reliably.
If the pump-retaining means has an elastomer element, this helps to damp the structure-borne sound of the fuel pump further. Furthermore, the elastomer element serves, alone or in addition to the resilient elements, for prestressing the fuel pump against the retaining part.
It is to be understood that both the foregoing general description and the following detailed description are not limiting but are intended to provide further explanation of the invention claimed. The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the invention. Together with the description, the drawings serve to explain the principles of the invention.
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pa
Lienig Klaus-Jurgen
Ludwig Norbert
Mannesmann VDO AG
Mayer Brown & Platt
Miller Carl S.
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