Abstract:
A fuel module, especially for the diesel fuel of an auto-ignition engine, having a fuel tank ( 10 ) and a fuel filter ( 11 ). The fuel tank ( 10 ) has a wall ( 12 ), which encloses the volume of the fuel tank ( 10 ), and the wall ( 12 ) has an opening in the region of the fuel filter ( 11 ). The fuel filter ( 11 ) is sealed to the wall ( 12 ) in the region of the opening and contains a filter medium ( 26 ), which is suitable for separating water from the fuel, which is to be cleaned. Also disposed within the fuel filter ( 11 ) is a water storage unit ( 38 ) in which water separated from the fuel is collected.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority from Federal Republic of Germany patent application no. DE 102004 024 466.9, filed May 14, 2004, the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a fuel module comprising a fuel tank and a fuel filter, in which the fuel tank comprises a wall which encloses the volume of the fuel tank, the wall has an opening in the area of the fuel filter, and the fuel filter is sealed to the wall in the vicinity of the opening. The fuel module of the invention is especially suitable for filtering and supplying diesel fuel to an auto-ignition engine, i.e. diesel engine. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved fuel module which comprises a fuel tank and a fuel filter. 
     Another object of the invention is to provide a fuel module which is especially suitable for diesel fuel for an auto-ignition engine. 
     These and other objects have been achieved in accordance with the present invention by providing a fuel module comprising a fuel tank and a fuel filter, the fuel tank having a wall which encloses the volume of the fuel tank, the wall having an opening in the area of the fuel filter, and the fuel filter being sealed to the wall in the vicinity of the opening, wherein the fuel filter comprises a filter medium which separates water from fuel passed through the filter, and wherein the fuel filter further comprises a water storage unit disposed within the fuel filter for receiving water separated from the fuel. 
     In accordance with a preferred embodiment of the invention, the fuel filter is connected by a bayonet lock with the fuel tank, and a seal is disposed in the bayonet lock in order to seal the arrangement. 
     In accordance with another preferred embodiment of the invention, a sensor, which can detect the degree to which the fuel tank is filled, is disposed in the fuel tank. 
     In yet another preferred embodiment, the fuel filter is provided with a water sensor which can detect the degree to which the water storage unit is filled. 
     In another preferred embodiment, a water suction pipe is provided, which is connected at one end with the water storage unit and at the other end to a water outlet through which collected water can be discharged outside of the fuel tank. 
     In a further preferred embodiments of the invention, the fuel filter has a support disposed on the fuel tank opposite the opening and/or the fuel filter includes a degassing device and/or the fuel filter is provided with a pre-heating unit for the fuel. 
     These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either alone or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described in further detail hereinafter with reference to illustrative preferred embodiments shown in the accompanying drawing figures, in which: 
         FIG. 1  is a diagrammatic view of a sector of a fuel module according to the invention; 
         FIG. 2  is a sectional view of a fuel filter for a fuel module according to the invention; 
         FIG. 3  is a sectional view of a sector of the fuel module of  FIG. 1 ; 
         FIG. 4  is a sectional view of a further sector of the fuel module of  FIG. 1 ; 
         FIG. 5  is a sectional view of a sector of the fuel filter of  FIG. 1 , and 
         FIG. 6  is a diagrammatic representation of a fuel module according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In  FIG. 1 , a sector of a fuel module is shown. The fuel module comprises a fuel tank  10  and a fuel filter  11 . The fuel tank  10  is constructed as a closed component, enclosing a volume, only a portion being shown. The capacity of the fuel tank  10  is designed so that an auto-ignition engine has a defined operating time at its disposal. 
     The auto-ignition engine may be disposed, for example, in a motor vehicle, the motor vehicle having a particular operating range. The motor vehicle, in which the fuel module is disposed, may, for example, be a truck, construction machinery or an agricultural machine. Of course, the fuel module of the invention can also be used in other motor vehicles. The larger the capacity, the greater is the operating range of the motor vehicle and the longer is the operating period the auto-ignition engine. 
     The fuel tank  10  has a wall  12 , which may be comprised of metal or synthetic resin material, i.e. plastic. This wall  12  limits the capacity of the fuel tank  10 , which may have any shape. Preferably, the fuel tank  10  is constructed as a rectangular block or cylinder. 
     The fuel filter  11  comprises a filter head  13  and a filter housing  14 . The fuel filter  11  is sealed to the wall  12  of the fuel tank  10 , the filter head  13  being outside and the filter housing  14  inside the fuel tank  10 . The filter head  13  includes a fuel outlet  15 , a fuel return pipeline  16  and a water outlet  17 . The fuel outlet  15  is connected correspondingly with an internal combustion engine (see  FIG. 6 ), so that purified fuel can be transported from the tank to the auto-ignition engine. 
     The fuel return pipeline  16  is also correspondingly connected with the auto-ignition engine and passes excess fuel or returning fuel from the auto-ignition engine back to the fuel filter  11 . The returning fuel is passed on to a pre-heater unit  18 , the fuel, which is to be cleaned, being mixed with the returning fuel in a manner depending on the fuel temperature and especially on the fuel temperature existing in the fuel tank  10 . Accordingly, blockage of the fuel filter  11  is prevented. 
     The fuel filter  11  has a fuel-intake pipeline  19 , which is constructed as a pipeline open at the front faces. Preferably, the fuel-intake pipeline  19  extends into the deepest place in the fuel tank  10 , so that the fuel is drawn in in a reliable manner even if the height of the fuel in the fuel tank  10  is slight. 
     The fuel level can be detected with a sensor  20 , which is equipped, in particular, as a sensor tape with a plurality of measuring sites. For this purpose, the sensor  20  protrudes throughout the fuel tank  10 , so that a maximum and a minimum fuel level, as well as intermediate level can be detected. The sensor has a male connector  23 , which can be connected with evaluating electronics (not shown), so that the level of fuel can be displayed on an output instrument (not shown). 
     In order to prevent vibrations of the fuel filter  11  during the operation of the auto-ignition engine, the fuel filter is supported with a supporting dome  21  at a corresponding seat  22  at the fuel tank  10 . The supporting dome  21  and the seat  22  are disposed perpendicularly underneath the filter head  13 . Accordingly, the fuel filter is fixed, on the one hand, at the filter head  13  and, on the other, at the supporting dome  21 . 
     The water outlet  17  is sealed with a screw cap  24 . When water is to be withdrawn from the fuel filter  11 , the screw cap  24  is removed and a corresponding suction unit (not shown) is connected. 
       FIG. 2  shows the fuel filter of  FIG. 1  in section. Components, corresponding to those of  FIG. 1 , are identified by the same reference numerals. The fuel filter  11  comprises a filter element  25 , which in turn comprises a filter medium  26 , a supporting tube  27  and end discs  28 . The filter medium  26  is sealed to the end discs  28  so that a hollow, cylindrical, internal space  29  is formed. 
     The supporting tube  27 , which prevents collapse of the filter medium  26 , is disposed in the internal space  29 , which forms the clean or filtered liquid side of the filter. The filter medium  26  is constructed so that water is separated from the fuel. For this purpose, media, known from the art, may be used. Furthermore, the filter element has a bypass valve  30 , which releases the flow path when the pressure difference is excessive. 
     An unfiltered liquid side  13 , which is connected via an intermediate space  32  with the fuel intake pipeline  19 , is formed between the filter element  25  and the filter housing  14 . The intermediate space  32  is formed between the upper end disc  28  and a cover  33 . The flow path for the fuel which is to be cleaned is indicated by arrow A. 
     The filter element  25  is sealed to the fuel pipe  34 , the fuel pipe being connected with the fuel outlet  15 . In this embodiment, the cover  33 , the fuel pipe  34  and the fuel outlet  15  are constructed in one piece. The cover  33  has a sealing ledge  35 , which contacts the filter housing  14  to form a seal. 
     A bayonet ring  36  is provided so that the cover  33  does not become loose in an uncontrolled manner during the operation of the fuel module. This bayonet ring  36  connects the cover  33  securely with the filter housing  14 . Furthermore, for changing the filter element  25 , the cover  33  can be detached easily from the filter housing  14 . Furthermore, the filter housing  14  has a bayonet lock  37 , with which the filter housing  14  can be sealed to the wall  12  of the fuel tank  10 . The seal-forming connection is produced over an axially compressed seal  39 . 
     A water storage device  38  for collecting the water separated from the fuel, is disposed in the filter housing  14 . Accordingly, the separated water is not mixed with the fuel remaining in the fuel tank  10 . The size of the water storage unit  38  is such, that a defined amount of water can be accommodated and the emptying of the war to storage unit  28  can take place after longer time intervals. 
     The fuel, which is to be cleaned, is passed through the fuel intake pipeline  19  from the fuel tank  10  into the intermediate space  32 . This can be accomplished by a suction pump (not shown) downstream, in the flow direction, from the fuel filter or by an upstream pressure pump (not shown). From the intermediate space  32 , the fuel flows, as indicated by arrow A, to the crude side  31  and through the filter element  25 . On the clean side  29 , the clean fuel enters the fuel pipeline  34  and flows through the fuel outlet  15  from the fuel filter  11 . If the pressure difference between the crude side  31  and the clean sides  29  is excessive, the bypass valve  30  opens up so that fuel, which has not been purified, reaches the clean side  29 . 
     In  FIG. 3 , a sector from the fuel module, especially from the fuel filter  11  of  FIG. 1 , is shown in section. Components which correspond to those in  FIGS. 1 and 2  are identified by the same reference numerals. A water suction pipe  40  is disposed in the fuel filter  11 , the water suction pipe  40  being connected, on the one hand, with the water storage unit  38  and, on the other, with the water outlet  17 . The water suction pipe  40  is constructed in one piece with the filter housing  14 , the outer wall of the filter housing  14  forming part of the water suction pipe  40 . 
     In the lowest region of the water storage unit  38 , the water suction pipe  40  is opened, so that almost the whole of the water can be exhausted from the water storage unit  38 . Preferably, the filter housing is made from synthetic resin material, so that the water suction pipe  40  can be produced in one step with the filter housing  14 . 
     A water sensor  41 , which extends through the whole of the filter housing  14 , is disposed in the filter housing  14 . In advantageous embodiments, the water sensor  41  can be constructed so that it can differentiate between different liquids, especially between fuel and water. Consequently, the phase boundary between fuel and water can be recognized, and the need to exhaust water from the water storage unit  38  can be indicated in good time. The water sensor can be connected via a connection  42  (of  FIG. 1 ) to an appropriate evaluating unit (not shown). 
     In  FIG. 4 , a further sector from the fuel module of  FIG. 1  is shown in a sectional view. Components corresponding to those in  FIGS. 1 to 3  are identified by the same reference numerals. For this sector, the fuel intake pipeline  19  is shown in section. Furthermore, the supporting dome  21  and the seat  22  are shown in section. The supporting dome is slipped onto the seat  22 , axial tolerances being equalized. The supporting dome  21  and the seat  22  are constructed as hollow components, particularly as pipes, the fuel being unable to penetrate into the interior. For other embodiments, these components  21  and  22  may also be permeable to the fuel. 
       FIG. 5  shows a sector from the fuel filter of  FIG. 1  in a sectional view taken along the line X-X. Components corresponding to those in  FIGS. 1 to 4  are identified by the same reference numerals. For this representation, a degassing unit  43  is shown in section. The degassing unit  43  is downstream from the pre-heater unit  18 . The fuel entering the fuel filter  11  through the fuel return pipeline  16  reaches a distributor space  44 , from where it can enter a tank return pipeline  45  and a conveying pipeline  46 . 
     A valve  50 , which is provided particularly for regulating the pressure in the conveying pipeline  46 , is disposed in the tank return pipeline  45 . The conveying pipeline  46  has a nozzle  51 , through which a defined jet of fuel can pass. A mixing space  52 , which is connected with the nozzle  51  as well as with a borehole  53 , is disposed, in the flow direction, after the nozzle  51 . The borehole  53  connects the mixing space  52  via an air pipeline  55  with the gas collection space  54 . 
     An ejector pump  56 , which aspirates gas from the air pipeline and the gas collection space  54  through the return pipeline from the conveying pipeline  46  and passes it into the fuel tank  10 , is disposed downstream from the mixing space  52 . The fuel filter is the thus degassed. Gas which collects in the fuel tank  10  is discharged through the venting system (not shown) of this tank  10  to the environment to the surroundings. 
     As shown especially in  FIGS. 1 and 5 , the pre-heating unit  18 , the de-gassing device  43 , the valve  50 , the tank return pipeline  45  and the conveying pipeline  46  are positioned closely together to form a compact unit in an upper part of the module. 
       FIG. 6  shows a diagrammatic representation of the fuel module according to the invention. A fuel filter  11  is disposed in the fuel tank  10 . For purposes of illustration, the relative proportions of the filter and tank to do not correspond to those likely to be used in actual practice. Naturally, the fuel tank may be constructed many times larger than the fuel filter  11 . Components corresponding to those described in the previous Figures are indentified by the same reference numerals. 
     A fuel-supplying pump  57 , which aspirates fuel via the fuel intake pipeline  19  from the fuel tank  10  into the fuel filter  11 , adjoins the fuel outlet  15 . The fuel is cleaned or filtered by the filter element  25 . Since the fuel-supplying pump  57  sucks up the fuel, gas bubbles are formed in the fuel filter and collect in the gas collection space  54  (see  FIG. 5 ) in the fuel filter  11 . Since the filter element  25  separates water contained in the fuel, the water, which has a higher density than the fuel, collects in the water storage unit  38  of the fuel filter  11 . 
     After the fuel-supplying pump  57 , the purified fuel is brought by a high-pressure pump  58  to the required operating pressure of a subsequent auto-ignition engine  59 . Any unconsumed fuel, supplied in excess, is provided as return flow to the fuel return pipeline  16 . If necessary, especially when the fuel temperature is too low, the return flow over the pre-heater a unit  18  is used to pre-heat the fuel, so that the filter element  25  does not become blocked. 
     Furthermore, the return flow can be used to degas the fuel filter  11 . For this purpose, the ejector pump  56  aspirates gas bubbles from the fuel filter  11 , the required pressure relationships being set by the valve  50 . The return flow, mixed with the gas bubbles, is then discharged to the fuel tank  10 . In the event that the functions of fuel pre-heating and/or degassing are not required, the return flow can also be discharged directly to the fuel tank. 
     The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations within the scope of the appended claims and equivalents thereof.