Fuel filter

Abstract

The present invention relates to a fuel filter ( 1 ) for a fuel supply system of an internal combustion engine, in particular in a motor vehicle, comprising a filter housing ( 2 ) and a filter element ( 3 ). The filter housing ( 2 ) has an untreated-side inlet ( 4 ), a treated-side outlet ( 5 ) and an untreated-side return line ( 6 ). The filter element ( 3 ) is arranged in the filter housing ( 2 ) and, therein, separates an untreated space ( 13 ), which communicates with the inlet ( 4 ) and with the return line ( 6 ), from a treated space which communicates with the outlet ( 5 ). Additionally provided is a closure element ( 20 ) which, in the operationally ready state of the fuel filter ( 1 ), closes off the return line ( 6 ).

1 . A fuel filter for an fuel supply system of an internal combustion engine, comprising:
 a filter housing, which has an untreated-side inlet, a treated-side outlet and an untreated-side return line,   a filter element which is arranged in the filter housing, the filter element including an untreated space and a treated space, and which separates in the filter housing the untreated space communicating with an inlet and the return line from the treated space communicating with the outlet,   a closure element which in an operationally ready state of the fuel filter closes-off the return line.   
   
   
       2 . The fuel filter according to  claim 1 , wherein the closure element is one of formed and arranged at the filter element, and, with the filter element inserted into the filter housing, closes-off the return line. 
   
   
       3 . The fuel filter according to  claim 1 , wherein the closure element is arranged at an end disk of the filter element shaped as ring filter element having at least one axial end disk. 
   
   
       4 . The fuel filter according to  claim 3 , wherein the closure element is shaped as a pin which projects axially from the respective end disk, and which, for closing the return line, closes-off a return line opening, which connects the return line with the untreated space. 
   
   
       5 . The fuel filter according to  claim 1 , wherein a positioning device is provided which comprises at least one positioning element on a filter element side, and at least one positioning element on a filter housing side, which interact during insertion of the filter element into the filter housing for finding of an orientation, which is aligned with an insertion direction of the closure element shaped as a pin, between the pin and a return line opening, which is open towards the untreated space, of the return line. 
   
   
       6 . The fuel filter according to  claim 4 , wherein the filter housing comprises a ramp which projects into the untreated space, which begins at the return line opening, extends circular concentric to a longitudinal center axis of the filter housing, ends at the return line opening, and declines from a beginning of the ramp to an end of the ramp towards the return line opening, and
 that the pin is arranged eccentric to a longitudinal center axis of the filter element and comprises a slide face which slides along the ramp during turning of the filter element around the longitudinal center axis of the filter housing for orienting the pin towards the return line opening.   
   
   
       7 . The fuel filter according to  claim 6 , wherein a guiding device is provided which comprises at least one guiding element on the filter element side, and at least one guiding element on the filter housing side, which interact during insertion of the filter element into the filter housing according to a key-lock principle such that the at least one guiding element on the filter element side and the at least one guiding element of the filter housing side allow for at least one of the following:
 interacting between the slide face and the ramp and   interacting between the ramp and the slide face only in case the at least one guiding element on the filter element side matches the at least one guiding element on the filter hosing side.   
   
   
       8 . The fuel filter according to  claim 7 , wherein the ramp along one of an entire extension of the ramp, and at least along an extension section of the ramp, is bordered at least one of radially inside and radially outside by at least one guiding wall which projects axially beyond the ramp, and
 that the pin comprises an axially projecting guiding section which comprises the slide face and which is positioned and dimensioned such that the pin extends radially alongside the respective guiding wall and thereby rests the slide face axially against the ramp, and keeps the pin axially spaced apart from the respective guiding wall.   
   
   
       9 . The fuel filter according to  claim 1 , wherein the return line in addition communicates with the untreated space through a vent throttle, the flow-through resistance of which is higher than the flow-through resistance through the filter element and through the outlet at the return line that is closed off. 
   
   
       10 . The fuel filter according to  claim 1 , wherein a pressure sensor is provided for measuring a treated-side fuel pressure. 
   
   
       11 . The fuel filter according to  claim 1 , wherein the filter element is shaped as a ring filter element, and comprises at least one axial end disk, from which a closure element projects axially and eccentrically, and a filter element is inserted into a filter housing of the fuel filter, closes-off an untreated-side return line of the filter housing. 
   
   
       12 . The fuel filter according to  claim 11 , wherein the closure element is a pin. 
   
   
       13 . The fuel filter according to  claim 2 , wherein the closure element is arranged at an end disk of the filter element shaped as ring filter element having at least one axial end disk. 
   
   
       14 . The fuel filter according to  claim 2 , wherein a positioning device is provided which comprises at least one positioning element on a filter element side, and at least one positioning element on a filter housing side, which interact during insertion of the filter element into the filter housing for finding of an orientation, which is aligned with an insertion direction of the closure element shaped as a pin, between the pin and a return line opening, which is open towards the untreated space, of the return line. 
   
   
       15 . The fuel filter according to  claim 2 , wherein the return line in addition communicates with the untreated space through a vent throttle, the flow-through resistance of which is higher than the flow-through resistance through the filter element and through the outlet at the return line that is closed off. 
   
   
       16 . The fuel filter according to  claim 2 , wherein a pressure sensor is provided for measuring a treated-side fuel pressure. 
   
   
       17 . The fuel filter according to  claim 2 , wherein the filter element is shaped as a ring filter element, and comprises at least one axial end disk, from which a closure element projects axially and eccentrically, and a filter element is inserted into a filter housing of the fuel filter, closes-off an untreated-side return line of the filter housing. 
   
   
       18 . The fuel filter according to  claim 3 , wherein the return line in addition communicates with the untreated space through a vent throttle, the flow-through resistance of which is higher than the flow-through resistance through the filter element and through the outlet at the return line that is closed off. 
   
   
       19 . The fuel filter according to  claim 3 , wherein a pressure sensor is provided for measuring a treated-side fuel pressure. 
   
   
       20 . The fuel filter according to  claim 3 , wherein the filter element is shaped as a ring filter element, and comprises at least one axial end disk, from which a closure element projects axially and eccentrically, and a filter element is inserted into a filter housing of the fuel filter, closes-off an untreated-side return line of the filter housing.