FUEL FILTER DEVICE FOR AN INTERNAL COMBUSTION ENGINE

Abstract

A fuel filter device for an internal combustion engine may include a water separator through which a fuel is flowable. To separate water contained in the fuel, the water separator may include a porous and hydrophilic membrane, which may include or be made of polymeric hollow fibers and which may be formed for cross-flow filtration of the fuel. A material of the hollow fibers may be hydrophilized via polyvinylpyrrolidone (PVP). The fuel filter device or the water separator may have a hydrophobic membrane for filtering residual fuel from the water separated via the hydrophilic membrane.

Claims

1.-16. (canceled)

17. A fuel filter device for an internal combustion engine, comprising: a water separator through which a fuel is flowable; wherein, to separate water contained in the fuel, the water separator comprises a porous and hydrophilic membrane, which comprises or is made of polymeric hollow fibers and which is formed for cross-flow filtration of the fuel; wherein a material of the hollow fibers is hydrophilized via polyvinylpyrrolidone (PVP); and wherein the fuel filter device or the water separator has a hydrophobic membrane for filtering residual fuel from the water separated via the hydrophilic membrane.

18. The fuel filter device according to claim 17, wherein the material of the hollow fibers comprises polyethersulfone.

19. The fuel filter device according to claim 17, wherein a pore size of the hydrophilic membrane is between 0.01 m and 5 m.

20. The fuel filter device according to claim 17, wherein the water separator comprises a final separator for separating residual water from the fuel cleaned via the hydrophilic membrane.

21. The fuel filter device according to claim 17, further comprising a filter housing, which surrounds a housing interior and in which the hydrophilic membrane is arranged, wherein a fuel inlet for introducing the unfiltered fuel, a fuel outlet for discharging the filtered fuel, and a water outlet for discharging the separated water are provided in the filter housing, wherein the fuel outlet is located opposite the fuel inlet, and the water outlet is arranged transversely to the fuel inlet or to the fuel outlet, respectively.

22. The fuel filter device according to claim 17, wherein the hydrophobic membrane is formed or set up for the cross-flow filtration of the water separated via the hydrophilic membrane.

23. The fuel filter device according to claim 17, wherein the hydrophobic membrane is formed as screen or as knitted wire mesh.

24. The fuel filter device according to claim 17, wherein the water separator has an electrical coalescer including two electrodes between which the hydrophilic membrane is arranged.

25. The fuel filter device according to claim 24, wherein a first one of the two electrodes is formed as a jacket electrode, which envelopes the hydrophilic membrane in a jacket-like manner, and that a second one of the two electrodes is formed as a central electrode, which is arranged in the membrane in a centered manner.

26. The fuel filter device according to claim 24, wherein the two electrodes are formed as coaxial cylinders.

27. The fuel filter device according to claim 24, wherein the electrical coalescer including the the electrodes has a direct current input voltage of 0-5.000 V, a pulsed direct current voltage of 0-5.000 V, or an alternating current input voltage of 0-40.000 V, wherein at least one of the direct current voltage has a frequency of 0-10.000 Hz and the alternating current input voltage has a frequency of 0-10.000 Hz.

28. A motor vehicle comprising: an internal combustion engine, in particular a diesel engine; a fuel reservoir, which is connected to the internal combustion engine via a fuel line to supply the internal combustion engine with fuel; and a fuel filter device arranged in the fuel line, the fuel filter device including a water separator through which a fuel is flowable; wherein, to separate water contained in the fuel, the water separator comprises a porous and hydrophilic membrane, which comprises or is made of polymeric hollow fibers and which is formed for cross-flow filtration of the fuel; wherein a material of the hollow fibers is hydrophilized via polyvinylpyrrolidone (PVP); and wherein the fuel filter device or the water separator has a hydrophobic membrane for filtering residual fuel from the water separated via the hydrophilic membrane.

29. The motor vehicle according to claim 28, further comprising a fuel return line, via which the residual fuel, which is discharged through the hydrophobic membrane, is returnable into the fuel reservoir.

30. The motor vehicle according to claim 28, wherein the fuel filter device or the water separator comprises a police filter, which is formed in such a way that it interrupts a fluid connection of the water separator to the external environment of the fuel filter device, when it is detected that a portion of residual fuel contained in the water exceeds a predetermined threshold value when the water separated from the water separator flows through the police filter.

31. The motor vehicle according to claim 28, wherein the internal combustion engine is a diesel engine and the fuel is diesel fuel.

32. The motor vehicle according to claim 17, wherein the material of the hollow fibers comprises polyethersulfone.

33. The motor vehicle according to claim 17, wherein a pore size of the hydrophilic membrane is between 0.01 m and 5 m.

34. The fuel filter device according to claim 19, wherein the pore size of the hydrophilic membrane is between 0.1 m and 1 m.

35. The fuel filter device according to claim 25, wherein the jacket electrode and the central electrode are formed as coaxial cylinders.

36. A fuel filter device for an internal combustion engine, comprising: a water separator through which a fuel is flowable; wherein, to separate water contained in the fuel, the water separator comprises a porous and hydrophilic membrane, which comprises or is made of polymeric hollow fibers and which is formed for cross-flow filtration of the fuel; wherein a material of the hollow fibers is hydrophilized via polyvinylpyrrolidone (PVP); wherein the fuel filter device or the water separator has a hydrophobic membrane for filtering residual fuel from the water separated via the hydrophilic membrane; wherein the material of the hollow fibers comprises polyethersulfone; and wherein the water separator has an electrical coalescer including two electrodes between which the hydrophilic membrane is arranged.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Preferred exemplary embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, in which

[0034] FIG. 1 shows, in schematic, circuit diagram-like manner, the setup of a motor vehicle according to the invention comprising the fuel filter device according to the invention.

[0035] FIG. 2 shows the setup of the water separator of the fuel filter device.

DETAILED DESCRIPTION

[0036] FIG. 1 shows, in schematic circuit diagram-like illustration, the components of a motor vehicle 20 according to the invention, which interact with the fuel filter device 1 according to the invention. According to FIG. 1, the motor vehicle 20 comprises an internal combustion engine 25, which can be realized as diesel engine, as well as a fuel reservoir 21, which s formed as fuel tank 22. The fuel reservoir 21 serves to supply the internal combustion engine with fuel K, in the case of the diesel engine thus with diesel fuel. For this purpose, the fuel reservoir 21 is connected to the internal combustion engine 25 by means of a fuel line 23. A fuel filter device 1 according to the invention is arranged in the fuel line 23.

[0037] The fuel filter device 1 is shown in FIG. 2 in separate illustration in a highly simplified longitudinal section. According to this, the fuel filter device 1 comprises a water separator 2, through which the fuel K or the diesel fuel, respectively, can flow. As can be seen in FIG. 2, the water separator 2 comprises a porous and hydrophilic membrane 3 for separating water W contained in the fuel K. The membrane 3 is operated in the mode cross-flow filtration and comprises a plurality of polymeric hollow fibers 4.

[0038] For the sake of clarity, only four such hollow fibers 4 are illustrated in a highly enlarged manner in the simplified illustration of FIG. 2. It is clear that a significantly larger number of hollow fibers 4 can be provided.

[0039] According to FIG. 2, the fuel filter device 1 comprises a filter housing 5, which surrounds a housing interior 6. The water separator 2 comprising the hydrophilic membrane 3 is arranged in the housing interior 6. The filter housing 5 is preferably formed in an elongate manner and extends along a longitudinal direction L in this case. The longitudinal direction L forms a main direction of extension H of the hollow fibers 4, i.e. the hollow fibers 4, which are not formed completely straight, nevertheless elongated hollow fibers 4, extend essentially along the longitudinal direction L of the filter housing 5. Along said longitudinal direction L, the housing interior 6 is limited by a circumferential wall 7 of the filter housing 5. An open first front side 10a of the filter housing 5 forms a raw-side fuel inlet 8 for introducing the unfiltered fuel into the housing interior 6. An open second front side 10b located opposite the first font side 10a forms an edge-side fuel outlet 9 for discharging the filtered fuel K. To seal the raw side 11 of the water separator 2 against the clean side 12 thereof, the hollow fibers 4 are fixed by means of a suitable plastic compound 24.

[0040] The fuel K to be filtered reaches out of the fuel reservoir 21 or the fuel tank 22, respectively, via the fuel line 23 to the fuel inlet 8 and is introduced via the latter into the housing interior 6. After the flow-through of the membrane 3 in the housing interior 6, the fuel K, which is discharged from the housing interior 6 via the fuel outlet 9, reaches via the fuel line 23 into the internal combustion engine 25.

[0041] A fuel return line 16 between the internal combustion engine 25 and the fuel reservoir 21 or the fuel tank 22, respectively, provides for the return of fuel K from the internal combustion engine 25 into the fuel reservoir 21 or into the fuel tank 22, respectively.

[0042] According to FIG. 2, a water outlet 13, via which the water W separated from the water separator 2 can be discharged from the filter housing 5, is also arranged in the filter housing 5 of the fuel filter device 1. According to FIG. 2, the fuel outlet 9 is located opposite the fuel inlet 8 along the longitudinal direction L, whereas the water outlet 13 provided in the circumferential wall 7 is arranged transversely to the fuel inlet 8 and to the fuel outlet 9. In the case of a suitable arrangement of the water separator 2 in such a way that the longitudinal direction L extends orthogonally to the direction of gravity G, the gravity acting on the separated water W can thus be used to separate water W from the fuel K particularly effectively and to subsequently discharge it from the water separator 2.

[0043] Polyethersulfone lends itself as base polymer for producing the polymeric hollow fibers 4 of the hydrophilic membrane 3. To provide it with the desired hydrophilic properties, the polyethersulfone is hydrophilized by means of polyvinylpyrrolidone. A pore size of the hollow fibers of the porous hydrophilic membrane 3 can be between 0.01 m and 5 m, preferably between 0.1 m and 1 m.

[0044] The water separator 2 can optionally comprise an additional final separator 17, which is only suggested in a roughly schematic manner in the figures, for separating residual water from the fuel, which is cleaned by means of the hydrophilic membrane 3.

[0045] The fuel filter device 1 can additionally be equipped with a further membrane 14, which, in contrast to the hydrophilic membrane 3, however, is formed to be hydrophobic, thus water-repellent. The hydrophobic membrane 14 serves the purpose of filtering residual fuel K, which may be present, out of the water W, which is separated by means of the hydrophilic membrane 3. Analogously to the hydrophilic membrane 3, the hydrophobic membrane 14 can also be formed for the cross-flow filtration of the water separated by means of the hydrophilic membrane. The hydrophobic membrane 14 can be formed as screen or as knitted wire mesh. For this purpose, the hydrophobic membrane 14, analogously to the hydrophilic membrane 3, can be integrated into a filter housing, as it is illustrated in FIG. 2. It is also conceivable, however, to integrate the hydrophilic membrane 3 as well as the hydrophobic membrane 14 into a single, common filter housing (not shown). With regard to the concrete design of the fuel filter device 1, in particular relating to the arrangement of the two membranes 3, 14 in a filter housing, different design options result for the pertinent person of skill in the art, from which he can select, depending on the application.

[0046] As can be seen in FIG. 2, the water separator 2 can also have an electrical coalescer 30 comprising two electrodes 26a, 26b, between which the hydrophilic membrane 3 is arranged. A first one of the two electrodes 26a is thereby formed as jacket electrode 27, which envelopes the hydrophilic membrane 3 in a jacket-like manner. A second one of the two electrodes 26b is formed as central electrode 28, which is arranged in the hydrophilic membrane 3 in a centered manner. Both electrodes 26a 26b, thus the jacket electrode 27 and the central electrode 38, can advantageously be formed as coaxial cylinder. A coaxial electrode arrangement of the two electrodes 26a, 26b offers the advantage that an inhomogeneous electrical field, which has a higher field line density in the area around the central electrode, is created by applying a voltage.

[0047] The electrical coalescer 30 can advantageously have a direct current input voltage of 0V to 5.000 V, a pulsed direct current voltage of 0 V to 5.000 V or an alternating current input voltage from 0 V to 40.000 V. The direct current voltage preferably has a frequency from 0 to 10.000 Hz and/or the alternating current input voltage has a frequency from 0 to 10.000 Hz. The two electrodes 26a, 26b can be connected to a suitable electrical voltage supply 29 for this purpose. Depending on the desired degree of separation and depending on the available voltage supply, it can thus be selected freely, with which type of electrical voltage the electrical coalescer 30 is operated.

[0048] Referring once again to FIG. 1, it can be seen that the motor vehicle 20 can be equipped with a fuel return line 15, which allows returning the residual fuel R separated from the water by means of the hydrophobic membrane 14 into the fuel reservoir 21 or the fuel tank 22, respectively.

[0049] The fuel filter device 1 or the water separator 2, respectively, can optionally comprise a police filter 18. This police filter 18 is preferably formed in such a way that it interrupts a fluid connection of the water separator 2 to the outer external environment 19 of the fuel filter device 1, if it is detected that the portion of residual fuel R still contained in the water W exceeds a predetermined threshold value, when the water W separated by the water separator 2 flows through the police filter 18.