Filter element and fuel filter

Abstract

The invention concerns a filter element (1), in particular of a fuel filter for motor vehicles. The filter element (1) is received in a filter housing (2) and comprises a filter body (3) with a filter material (5) that is arranged in folds (4). Between two folds (4) a heater installation space is provided and configured to receive a heating element (6) for the fuel.

Claims

1. A filter element of a motor vehicle fuel filter, comprising: a filter body arranged within an interior of a filter housing, said filter body having a raw unfiltered side and a clean filtered side, said filter body including; a terminal disk having a through opening; a cylindrical filter material arranged into a plurality of folds within said filter body around a central axis; at least one heating element installation space formed between two neighboring folds of said filter material, said neighboring folds of said at least one heating element installation space being spread apart in a circumferential direction wider than other pairs of neighboring folds of said plurality of folds to form at least one heating element installation configured to receive an electric heating element therein between said two neighboring folds to heat fuel in said filter body; wherein said at least one heating element installation space extends substantially parallel with said central axis of said cylindrical filter media between said two neighboring folds at a radially outer side of said filter material; wherein at least one of said at least one heating element installation space is positionally correlated with said through opening of said terminal disk; wherein said filter element is configured for use in said filter housing.

2. A fuel filter for motor vehicles comprising: a filter housing including a lid part; a filter element according to claim 1 received into said filter housing; wherein between said terminal disk and said lid part a supply chamber is defined within said filter housing; a supply line in fluid communication with said supply chamber and configured to supply fuel to said supply chamber; and wherein said through opening in said terminal disk adjoins said heating element installation space.

3. The fuel filter according to claim 2, wherein said heating element installation space is arranged on the raw side of the filter body; wherein said heating element installation space is arranged axially directly under said through opening in said terminal disk such that said through opening opens directly into said heating element installation space.

4. The fuel filter according to claim 2, wherein said lid part of said filter housing includes a second through opening, said second through opening adjoining and aligned with said through opening of said terminal disk; wherein said second through opening is arranged axially directly over said through opening in said terminal disk.

5. The fuel filter according to claim 2, wherein the heating element comprises a differential pressure sensor configured to detect and be responsive to differential pressure between the raw side and the clean side of the filter body; wherein the pressure sensor is connected to control an electric fuel pump in a low-pressure circuit of the fuel supply and/or control heating power supplied to the heating element.

6. The fuel filter according to claim 2, wherein the through opening in said terminal disk is connected to a hydrodynamic conducting body configured to guide fuel flowing into said through opening directly to said at least one heating element installation space.

7. The fuel filter according to claim 6, further comprising electrical connecting contacts secured on said heating element and accessible through a contact opening in said lid part; and a seal sealing between said lid part and said heating element configured to isolate said contacts from fuel flow.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) One exemplary embodiment of the invention will be explained in the following with the aid of the drawing in more detail. The only FIGURE shows in a partially sectioned illustration a diesel fuel filter with a filter element embodied in accordance with the invention with an integrated fuel heater.

EMBODIMENT OF THE INVENTION

(2) The only FIGURE shows in a partially sectioned illustration of one exemplary embodiment of a fuel filter 10 for diesel fuel for a motor vehicle that is embodied in accordance with the present invention. Other applications and in particular other fuel types can be envisioned also. The fuel filter 10 comprises a filter housing 2 that is closed off by a lid part 13 that may be detachable. In the filter housing 2 a filter element 1 is secured which may be removed in predetermined servicing intervals after detachment of the lid part 13 and is replaced with a new filter element 1.

(3) The filter element 1 comprises a filter body 3 with a filter material 5 that is arranged in folds 4. As filter material 5 filter paper is provided. However, other filter materials 5 may be expedient also. The extension of the folds 4 is indicated by dashed lines 26. The filter housing 2 and the filter body 3 are substantially embodied to be cylindrical wherein the folds 4 extend in radial direction and parallel to the longitudinal axis of the cylindrical filter element 1 or the cylindrical filter housing 2. External to the filter material 5 in radial direction there is the raw side 7 of the filter element 1. In the radial inner area an approximately cylindrical cavity is provided that forms the clean side 8 of the filter element 1. In operation, the filter material 5 is flown through radially from the outer raw side 7 to the inner clean side 8. When doing so, a differential pressure between the raw side 7 and the clean side 8 is generated that acts inwardly in the radial direction on the filter material 5. For supporting the filter material 5 relative to this differential pressure, a support grid 24 is arranged inwardly in radial direction.

(4) At both end faces, the filter body 3 has a terminal disk 11, 22, respectively. In the illustrated embodiment the terminal disk is provided with edges seals 12, 23 that extend circumferentially about the circumference in the form of elastic sealing lips. The seal 12 arranged in the area of the lid part 13 seals the terminal disk 11 relative to the filter housing 2 as well as relative to the lid part 13. The seal 23 of the axially oppositely positioned terminal disk 22 is resting seal-tightly against the inner circumferential surface of the filter housing 2. In the terminal disk 11 that is facing the lid part 13 a through opening 16 is integrally formed. The two terminal disks 11, 22 with their sealing lips 12, 23, the circumferential wall of the filter housing 2, and the filter body 3 delimit a closed annular space at the raw side 7 of the filter element 1 whose only access is the through opening 16.

(5) As a result there is also a closed supply chamber 14 formed between the terminal disk 11 and the lid part 13 into which a supply opening 15 opens. Into this supply chamber 14 fuel is introduced through the supply line 15. The fuel flows in accordance with arrow 25 through the supply chamber 14 to the through opening 16 and through it into the afore described annular space of the raw side 7. From here the fuel flow is guided radially from the exterior to the interior through the filter material 5 into the radially inwardly positioned space that defines the clean side 8 from where the fuel flows out through a central outlet line 20 of the lid part 13. For separating the supply chamber 14 from the outlet line 20, a seal 21 is arranged between the terminal disk 11 and the lid part 13 and extends circumferentially about the mouth of the outlet line 20.

(6) Between two folds 4 of the filter material 5 an electric heating element 6 for the fuel is arranged. For this purpose, the two neighboring folds 4 are spread apart in the circumferential direction in order to provide sufficient space for the heating elements 6. The heating element 6 is positioned relative to the circumferential contour of the filter body 3 inwardly displaced in the radial direction and is fixedly connected to the filter element 1. At the predetermined servicing intervals an exchange of the filter body 3 together with the heating element 6 is provided.

(7) The heating element 6 extends parallel to the axis of the filter body 3 between its two terminal disks 11, 22. A contact opening 18 is formed integrally in the lid part 13 and the adjoining terminal disk 11 which contact opening enables an electric plug connection with electrical connecting contacts of the heating element 6 and a differential pressure sensor 9 to be described infra. The heating element 6 is sealed relative to the lid part 13 and the terminal disk 11 with a seal 19 circumferentially surrounding the contact opening 18. In this way, the electric connecting contacts are kept away from the fuel flow.

(8) The through opening 16 of the terminal disk 11 that is seal-tightly closed off relative to the contact opening 18 adjoins the correlated end face of the heating element 6; the hydrodynamic conducting body 17 integrally formed in the terminal disk 11 ensures a controlled flow of the fuel introduced through the through opening 16 toward the heating element 6. The fuel flow is guided approximately axis-parallel along the heating element 6 and is heated thereby. Subsequently, it is distributed in the afore described annular space of the raw side 7 before it passes in the radial direction inwardly through the filter material 5 to the clean side 8. In an exemplary fashion, a single heating element 6 is shown between two folds 4 with a correlated through opening 16. However, it may also be expedient to provide two or more heating elements 6 with a corresponding number of through openings 16.

(9) The heating element 6 is also provided with a schematically indicated differential pressure sensor 9 which is provided for detecting a differential pressure between the raw side 7 and the clean side 8 of the filter body 3. The differential pressure of the fuel flow that is generated upon passing through the filter element 1 from the raw side 7 to the clean side 8 is determined by the differential pressure sensor 9 and is used by a non-illustrated control or governing unit as a measure for the viscosity of the fuel. Depending on the determined measured value the conveying output of an electric fuel pump, not illustrated, in the low-pressure circuit of the fuel supply and/or the heating power of the heating element 6 can be controlled or regulated in order to ensure a satisfactory volume flow of the fuel through the fuel filter 10 even at low temperatures of the surroundings.