FUEL FILTER FOR CLEANING FUEL FOR AN INTERNAL COMBUSTION ENGINE

Abstract

The invention relates to a fuel filter (1) for cleaning fuel (K) for an internal combustion engine (20), having a main filter (3) and a prefilter (2) which is arranged upstream of the main filter (3), through which fuel (K) can successively flow, wherein the prefilter (2) has for separating water (W) present in the fuel (K) a water separator (4) which comprises a water collection chamber (5) for collecting the separated water (W), wherein the prefilter (2) is connected in fluid terms to the main filter (3) by means of a conveying device (18) which conveys the fuel from the prefilter into the main filter (3), having a suction jet pump (6) which is connected in fluid terms to the water collection chamber (5) in order to discharge water (W) from the water collection chamber (5).

Claims

1. Fuel filter (1) for cleaning fuel (K) for an internal combustion engine (20), having a main filter (3) and a prefilter (2) which is arranged upstream of the main filter (3), through which fuel (K) can successively flow, wherein the prefilter (2) has for separating water (W) present in the fuel (K) a water separator (4) which comprises a water collection chamber (5) for collecting the separated water (W), wherein the prefilter (2) is connected in fluid terms to the main filter (3) by means of a conveying device (18) which conveys the fuel (K) from the prefilter (2) into the main filter (3) and which builds up an excess pressure at that location, having a suction jet pump (6) which is connected in fluid terms to the water collection chamber (5) in order to discharge fuel (K) and/or water (W) from the water collection chamber (5).

2. Fuel filter according to claim 1, characterised in that there is present on the main filter (3) a fuel outlet (7) which communicates in fluid terms with the suction jet pump (6) so that the fuel (K) flowing through the fuel outlet (7) acts as a propellant of the suction jet pump (6).

3. Fuel filter according to claim 1 or 2, characterised in that in the water collection chamber (5) an outlet (29) to the suction jet pump (6) is constructed as an overflow (31) which limits the filling level for water in the water collection chamber (5) and/or in that in a lower region (28) of the water collection chamber (5) a water outlet is provided.

4. Fuel filter according to claim 3, characterised in that a water level sensor (34) for detecting water (W) is provided in the water collection chamber (5) below the outlet (29) to the suction jet pump (6).

5. Fuel filter according to any one of claims 2 to 4, characterised in that the fuel outlet (7) communicates via the suction jet pump (6) in fluid terms with an additional water separator (8) for separating the fuel (K) which acts as a propellant from the water (W) which is conveyed out of the water separator (4).

6. Fuel filter according to claim 5, characterised in that there is arranged in the additional water separator (8) a water separator fuel outlet (30) which in order to discharge the fuel (K) which has accumulated in the additional water separator (8) communicates in fluid terms with a fuel reservoir (9).

7. Fuel filter according to any one of the preceding claims, characterised in that the main filter (3) has a filter housing (12) in which there is arranged a filter element (13) which subdivides a housing inner space (14) which is delimited by the filter housing (12) into a dirty side (15) and a clean side (16), wherein the fuel outlet (7) of the main filter (3) extends to the suction jet pump from the dirty side (15) and the line is also used to ventilate the fuel filter in the direction towards the tank. wherein a fuel outlet (17) for discharging the cleaned fuel (K) from the fuel filter (1) into the internal combustion engine (20) is present in the clean side (16).

8. Fuel filter according to any one of the preceding claims, characterised in that the main filter (3) has a filter housing (12), in which there is arranged a filter element (13) which subdivides a housing inner space (14) which is delimited by the filter housing (12) into a dirty side (15) and a clean side (16), wherein the fuel outlet (7) of the main filter (3) extends to the suction jet pump from the clean side (16), wherein a fuel outlet (17) for discharging the cleaned fuel (K) from the fuel filter (1) into the internal combustion engine (20) is further present in the clean side (16).

9. Fuel filter according to any one of claims 5 to 8, characterised in that the suction jet pump (6) is arranged in a connection line (9) which connects the main filter (3) in fluid terms to the additional water separator (8).

10. Fuel filter according to any one of the preceding claims, characterised in that the water separator (4) has a separator housing (25) which delimits a housing inner space (26) through which the fuel (K) can flow, wherein a hydrophobic membrane through which the fuel (K) can flow in order to separate the water (W) which is contained in the fuel (K) is arranged in the housing inner space (26).

11. Fuel filter according to any one of the preceding claims, characterised in that in the connection line (19) between the water collection chamber (5) and suction jet pump (6) there is arranged a non-return valve (33) which permits flow from the water collection chamber (5) to the suction jet pump (6) but prevents flow from the suction jet pump (6) into the water collection chamber (5).

12. Fuel filter according to claim 10 or 11, characterised in that the water collection chamber (5) of the water separator (4) is formed by a lower region (28) of the housing inner space (26) with respect to the direction of gravitational force (S), wherein there is provided an outlet (29) which communicates in fluid terms with the suction jet pump (6) and which limits a filling quantity of water (W) in the water collection chamber (5) to a predetermined maximum value.

13. Internal combustion engine (20) for a motor vehicle, having cylinders (21), in which a combustion chamber (22) is provided in each case, wherein each cylinder (21) has at least one fuel injector (23) for injecting fuel (K) into the respective combustion chamber (22), wherein the internal combustion engine (20) comprises at least one fuel supply (24) for introducing the fuel (K) into the fuel injectors (23), wherein a fuel filter (1) according to any one of the preceding claims is arranged upstream of the at least one fuel supply (24).

14. Motor vehicle having an internal combustion engine (20) according to claim 13.

Description

[0027] In the schematic drawings:

[0028] FIG. 1 shows in a highly schematic manner the structure of a fuel filter according to the invention in the manner of a circuit diagram,

[0029] FIG. 2 shows a variant of the fuel filter of FIG. 1 with an additional water separator.

[0030] In the manner of a circuit diagram, FIG. 1 schematically illustrates the structure of a fuel filter 1 according to the invention for cleaning fuel K for an internal combustion engine. In this instance, FIG. 1 describes a fuel filter having a water discharge means from the water collection chamber and FIG. 2 describes an advantageous development with an additional water separator which serves to separate the fuel which acts as a propellant.

[0031] The fuel filter 1 comprises according to FIG. 1 a main filter 3 and a prefilter 2 which is arranged upstream of the main filter 3. There is provided upstream of the prefilter 2 a fuel reservoir 9 which is produced as a fuel tank 10 with the fuel K which is intended to be cleaned. The fuel K can flow successively through the two filters 2, 3. The prefilter 2 comprises a water separator 4 for separating water W present in the fuel K.

[0032] The water separator 4 has a separator housing 25 which delimits a housing inner space 26 through which the fuel K can flow. A hydrophobic membrane 27 through which the fuel K can flow to separate the water W present in the fuel K is arranged in the housing inner space 26 of the water separator 4. The water separator 4 also has a water collection chamber 5 for collecting the water W which has been separated in the water separator 4. The prefilter 2 is connected in fluid terms to the main filter 3 by means of a conveying device 18. The conveying device 18 conveys the fuel K from the prefilter 2 into the main filter 3. Furthermore, the fuel filter 1 comprises a suction jet pump 6 which is connected in fluid terms to the water collection chamber 5 of the water separator 4. By means of the suction jet pump 6 which is illustrated in FIG. 1 only in a highly schematic manner, medium is permanently discharged from the water collection chamber 5. Separated water which is present in the water collection chamber 5 below the outlet to the suction jet pump remains in the water collection chamber 5 (cf. FIG. 1). In contrast, fuel K and water W above the outlet are discharged directly therefrom via the suction jet pump 6.

[0033] The water collection chamber 5 of the water separator 4 is formed by means of a lower region 28 of the housing inner space 26 with respect to the direction of gravitational force S when the water separator 4 is located in a position for use. In the lower region 28 of the housing inner space 26, there is provided an outlet 29 which communicates in fluid terms with the suction jet pump 6. As a result of the spacing of the outlet 29 with respect to the positionally lower bottom end of the housing inner space 26, the maximum filling level for water in the water collection chamber can be adjusted. In this manner, by means of the suction jet pump 6 the water W above a desired filling level can be pumped out of the water collection chamber 5. A water level sensor 34 which indicates the presence of water W at the outer side, for example, with an electrical signal, may be arranged below the outlet 29 and consequently within the maximum filling level for water W and can indicate the presence of water W at the outer side. On the housing base of the lower region 28 of the water collection chamber 5, a water outlet 32 may be arranged in order to discharge water from the fuel filter 1 into the environment.

[0034] As can be seen in FIG. 1, the main filter 3 comprises a fuel outlet 7 which communicates in fluid terms with the suction jet pump 6. In this manner, the fuel which flows through the fuel outlet 7 and which is supplied to the suction jet pump 6 can be used as a propellant for the water W which is intended to be conveyed by the suction jet pump 6 from the water separator 4. The main filter 3 has a filter housing 12 which is illustrated only in a highly schematic manner in FIG. 1 and in which a filter element 13 is preferably arranged so as to be able to be replaced. The filter element 13 subdivides the housing inner space 14 delimited by the filter housing 12 into a dirty side 15 and a clean side 16. In the clean side 16, a fuel outlet 17 for discharging the cleaned fuel K from the fuel filter 1 into an internal combustion engine 20 is present. According to FIG. 2, the suction jet pump 6 is arranged in a connection line 7 which connects the dirty side 15 of the main filter 3 to the additional water separator 8 in fluid terms. The medium from this line drives the suction jet pump 6. Furthermore, the suction jet pump 6 is connected in fluid terms by means of a connection line 19 to the water collection chamber 5 and draws the medium from the water collection chamber 5.

[0035] The internal combustion engine 20 which is illustrated only in a highly schematic manner in FIG. 1 has, for example, four cylinders 21 in which an internal combustion chamber 22 is present in each case. Each cylinder 21 has a fuel injector 23 for injecting the cleaned fuel K into the respective combustion chamber 22. The internal combustion engine 20 has a fuel supply 24 for introducing the fuel K into the fuel injectors 23. The fuel filter 1 according to the invention is consequently arranged upstream of the fuel supply 24. The fuel reservoir 9 or the fuel tank 10 has a fuel outlet 11 which communicates via the prefilter 2, the conveying device 18 and the main filter 3 with the internal combustion engine 20.

[0036] FIG. 2 shows a variant of the example of FIG. 1. According to FIG. 2, the fuel outlet 7 communicates via the suction jet pump 6 in fluid terms with an additional water separator 8 in order to separate the fuel which acts as a propellant from the water W which is conveyed by the suction jet pump from the water separator 4 or the water collection chamber 5 thereof. In the additional water separator 8, there may be arranged a water separator fuel outlet 30 which in order to discharge the fuel present in the water separator 4 communicates in fluid terms with the fuel reservoir 9 or with the fuel tank 10. Furthermore, in the additional water separator 8 a water level sensor 34 for water may be arranged and may indicate the presence of water at the outer side, for example, using an electrical signal. In the lower region 36 of the additional water separator 8, a water outlet 35 may be arranged in order to discharge water W from the filter system into the environment.

[0037] According to FIG. 1 and FIG. 2 there is provided in the connection line 19 from the water collection chamber to the suction jet pump 6 a non-return valve 33 which permits flow from the water collection chamber 5 to the suction jet pump 6 and which blocks flow from the suction jet pump 6 to the water collection chamber 5.