GB2262567A

GB2262567A - Silencing fuel feed apparatus.

Info

Publication number: GB2262567A
Application number: GB9218308A
Authority: GB
Inventors: Karl-Heinz Werkmann
Original assignee: Mannesmann VDO AG
Current assignee: Mannesmann VDO AG
Priority date: 1991-12-20
Filing date: 1992-08-28
Publication date: 1993-06-23
Anticipated expiration: 2012-08-28
Also published as: GB2262567B; DE4142268A1; FR2685262A1; GB9218308D0; DE4142268C2

Description

2262567 FUEL FEED APPARATUS The invention relates to a fuel feed apparatus

for the delivery of fuel from a supply tank to an internal combustion engine.

Such a fuel feed apparatus usually has a substantially cylindrical feed unit which is situated in the supply tank, at least the cylindrical edge, region of the feed unit being surrounded by a damping element which damps the noises produced by the feed unit.

In a fuel feed apparatus of this kind it is known for the damping element to be a closed gas-filled chamber surrounding the cylindrical -,jall of the feed unit. The pores of a closed-pore foam can form the chambers. This fuel feed apparatus has the disadvantage that it is fundamentally difficult to ensure a permanent gas filling in the chambers. When gas loss occurs due to damage or diffusing-out over a relatively long period of time, the damping element loses its effect at least partially.

Therefore the invention has as its object to provide a fuel feed apparatus whose high noise-damping action is less susceptible to reduction over time.

The present invention provides a fuel feed apparatus in which a damping element is made of a porous open-pore sintered material. Because of this construction the pores of the damping element, which is made preferably of synthetic plastic material, are at least partially filled with fuel, so that a loss of gas does not result in a loss of sound-damping effect. This is achieved due to the fact that, as sound waves pass through the porous sintered material, sound absorption takes place at the irregular surfaces of the particles in the pore channels.

- 2 It is particularly advantageous if the sintered material consists of particles with an irregular surface.

If, in addition, the sintered material is an elastic material, the sound waves cause deformation phenomena and thus produce internal friction in the material, so that energy conversion to heat occurs and thus propagation of the sound waves is considerably inhibited.

The pore width of the sintered material can amount to approximately a value of between 10 pm and 200 pm, preferably between 20 pm and 100 pm.

The damping effect can be multiplied in a simple manner if the damping element is of multi-wall construction.

One possibility for the arrangement of the damping element is for the damping element to surround the fQed, unit and abut on a wall region (possibly cylindrical-) thereof or even to form the housing of the feed unit.

In another advantageous feature the damping element, with a pot-like shape, surrounds the feed unit, in a spaced relationship.

If the damping element at least at one of its axial ends has a radially inwardly directed flange, with which it abuts on the feed unit, surrounding the latter, considerable sound absorption in the axial direction is also achieved.

If the feed unit comprises a tubular suction neck which is directed preferably axially to the base of the supply tank and which is surrounded by a tubular damping neck of the damping element, sound transmission in the region of the tubular suction neck is also damped.

This damping can be further improved if that end of the tubular damping neck which is directed towards the base of the supply tank is of closed construction. In that case the tubular damping neck constitutes a fuel filter at the 3 - same time, fulfilling a double function.

To obtain sound-deadening in a direction axially upwardly from the feed unit, the end-face region of the feed unit remote from the base of the supply tank can be surrounded by the damping element.

In an optimum arrangement the feed unit can be encapsulated at least substantially by the damping element.

To allow simple assembly and manufacture of the damping element, the damping element can be of multi-part con- 0 - struction.

The feed unit and damping element can be arranged in a closed fuel container fixable to the base of the supply tank, and surrounded by the said container such that an annular space is formed between feed unit and fuel container. Into the annular space fuel can be delivered from the first stage of a two-stage feed unit as also where appropriate from a return duct of an injection system, and drawn by suction thence through the second stage of the feed unit. Since the damping element is liquidpervious the damping element does not cause division of the annular space into a plurality of spaces or chambers.

Preferably the damping element is arranged with a radial spacing from the fuel container in the annular space, since in this way there is further noise reduction due to the free elastic mobility of the damping element. It is particularly advantageous if the damping element at least in one of the axial end regions has a collar which abuts on the generated surface of the feed unit and which is surrounded radially by the base and/or the top cover region of the fuel container. In this arrangement, the feed unit is supported by the fuel container, the connection between feed unit and fuel container being damped as regards structure-borne sound.

4 - An O-ring can be arranged between the generated surface of the feed unit and the collar, for sealing the annular space relatively to the supply tank.

One constructional example of the invention is shown in the drawing and will be described in more detail hereinafter. The sole Figure of the drawing shows a view in cross-section of a fuel feed apparatus.

The fuel feed apparatus shown in the Figure has a two-stage feed unit 1, whose first pump stage is a preliminary feed pump 2 constructed as a peripheral impeller pump and whose second pump stage is, a.main feed pump 3 constructed as a Gerotor pump. The rotors of the two pumps 2 and 3 are situated on the same drive shaft 4, adapted to be driven in rotational movement by an electric motor 5.

The electric motor 5 and pumps 2 and 3 form the feed unit 1 which is arranged in a common housing 6 and is situated with the drive shaft 4 perpendicular to the container 7 of a supply tank. This feed unit 1 is so arranged in a fuel container 8 that an annular space 9 is formed between the substantially cylindrical generated surface of the feed unit 1 and that wall of the fuel container 8 which surrounds the said generated surface.

The fuel container 8 is connected via vibrationdecoupling elastic connecting elements 10 to a holder device 11 which supports the fuel container 8. The holder device 11 has at its end nearest to the base 7 a bayonet ring 12 by means of which it is fixable to a corresponding bayonet counter-ring 13 which is integral with the base.

The feed unit 1 has a tubular suction neck 25 which is directed coaxially to the base 7 of the Supply tank and which opens into the region surrounded by the bayonet counter-ring 13 and communicating with the supply tank, and through which the preliminary feed pump 2 draws fuel by suction from the supply tank.

From the preliminary feed pump 2 the fuel is conveyed through its compression port 14 into the annular space 9 from which again the fuel is aspirated via a suction port 15 by the main feed pump 3. The main feed pump 3 delivers the fuel through the housing of the electric motor 5 and a non-return valve 16 to a compression port 17 from which it passes through a flexible conduit 18 to an internal combustion engine not shown here.

A return from the internal combustion engine debouches via a return port 19 likewise into the annular space 9, so that the latter also receives excess returned fuel.

At the outside of the fuel tank 8 there is also pivotably mounted one end of a float lever 20 whose other end carries a float 21 and which also with a slider slides along a potentiometer 22 arranged on the fuel container 8.

A substantially tubular damping element 23 is arranged in the annular space 9 with spacing both from the substantially cylindrical shell region of the feed unit 1 and also from the internal wall of the fuel container 8. The damping element 23 is made of a porous open-pore sintered material whose particles have an irregular surface and which constitutes an elastic soft material comprising synthetic plastic material.

At the base side the damping element 23 has a radially inwardly directed flange 24 joining a tubular damping neck 26 which surrounds the tubular suction neck 25 with slight spacing and which leads to the base 7. An Oring 27 is 6 arranged between the tubular suction neck 25 and the tubular damping neck 26. The fuel container 8 also has a base 28 on which the flange 24 of the damping element 23 bears and which with the radially encircling edge surface of an aperture 29 formed in it abuts on the tubular damping neck 26. The feed unit 1 is held in the fuel container 8 by the clamping effect with which the tubular suctionneck 25 is arranged by means of the O-ring and the tubular damping neck 26 in the aperture 29.

At its region remote from the base 7 the fuel container 8 is closed by an inserted cover or lid 30. The lid 30 has a tubular neck 31 surrounding with a small spacingthe upper region of the feed unit 1. Both the tubular inner surface of the lid 30 and also the tubular neck 31 are provided with a separate layered portion of damping element 23', the tubular neck 31 supporting the damping element 23' collar-like both radially internally and radially externally.

An O-ring 32 is arranged between on the one hand the damping element 23' situated internally on the tubularneck 31 and on the other hand the feed unit 1 in the same way as at the base-region end thereof, so that here also the feed unit 1 is held securely on the fuel container 8 under preload.

At the end region remote from the base 7 the feed unit is covered by a further pot-shaped part of the damping element 23", the pot edge being secured on the lid 30 of the fuel container 8.

Likewise the region below the feed unit 1 can also be provided with a damping element, not shown here, which element may be arranged directly on the base 7 of the container. For this purpose e.g. that region of the base 7 which is surrounded by the bayonet counter-ring 13 can be provided with the damping element.

7

Claims

CLAIMS:

1. Fuel feed apparatus suitable for the delivery of fuel from a supply tank to an internal combustion engine, having a feed unit to be arranged in the supply tank, at least part of the feed unit being shielded by a damping element which damps the noises produced by the feed unit, characterised in that the damping element is made of a Porous, open-pore sintered material.

2. Fuel feed apparatus according to claim 1, wherein the sintered material is made of particles having an irregular surface.

3. Fuel feed apparatus according to any one of the preceding claims, wherein the sintered material is an elastic material.

4. Fuel feed apparatus according to any one of the preceding claims, wherein the pore width of the sintered material amounts to approximately a value of between 10 pm and 200 pm.

5. Fuel feed apparatus according to claim 4, wherein the pore width of the sintered material amounts to approximately a value of between 20 pm and 100 pm.

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6. Fuel feed apparatus according to any one of the preceding claims, wherein the damping element is of multiwall construction.

7. Fuel feed apparatus according to any one of the preceding claims, wherein the damping element surrounds the feed unit such as to abut a wall region thereof.

8. Fuel feed apparatus according to any one of claims 1 to 6, wherein the damping element is a pot-like element surrounding the feed unit at a spacing therefrom.

9. Fuel feed apparatus according to claim 8, wherein the damping element at least at one of its axial ends has a radially inwardly directed flange with which it abuts against the feed unit, surrounding the latter.

10. Fuel feed apparatus according to any one of the preceding claims, wherein the feed unit has a tubular suction neck which is directed preferably axially to the base of the supply tank, and which is surrounded by a tubular damping neck of the damping element.

11. Fuel feed apparatus according to claim 10, wherein that end of the tubular damping neck which faces towards the base of the supply tank is of closed construction.

12.

9 Fuel feed apparatus according to any one of the preceding claims, wherein that end face region of the feed unit whicL is remote from the base of the supply tank is surrounded by the damping element.

13. Fuel feed apparatus according to any one of the preceding claims, wherein the feed unit is at least substantially encapsulated by the damping element.

14. Fuel feed apparatus according to any one of the preceding claims, wherein the damping element is of multi- part construction-

15. Fuel feed apparatus according to any one of the preceding claims, wherein the feed unit and the damping element are arranged in a closed fuel container and are surrounded thereby such as to form an annular space between the feed unit and the fuel container, said container being fixable to the base of the supply tank.

16. Fuel feed apparatus according to claim 15, wherein the damping element is situated at a radial spacing from the fuel container in the annular space.

17. Fuel feed apparatus according 'to claim 15, wherein the damping element at least in one of the axial end regions has a collar which abuts on the generated surface of the feed unit and which is surrounded radially by the base and/or the lid region of the fuel container.

18. Fuel feed apparatus according to claim 17, wherein an 0-ring is situated between the generated surface of the feed unit and the collar.

19. Fuel feed apparatus substantially as herein described with reference to and as illustrated in the accompanying drawing.

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