Patent Abstract:
A filtering system ( 9 ) includes a filter head ( 12 ) and a replaceable filter ( 10 ). The filter head ( 12 ) has a feed line ( 66 ) and discharge line ( 62 ). The replaceable filter ( 10 ) is removable and replaceably mounted onto the filter head ( 12 ) by a rotational and/or plug connection ( 15 ) and includes a housing ( 17 ) with at least one inlet ( 26 ) for oil to be filtered and at least one outlet ( 28 ). The inlet ( 26 ) communicates with the feed line ( 66 ). The outlet ( 28 ) communicates with the discharge line ( 62 ). The housing ( 17 ) has a filtering element ( 34 ) that sealingly separates the inlet ( 26 ) from the outlet ( 28 ). The filter head ( 12 ) includes an auxiliary oil line ( 60 ). The replaceable filter ( 10 ) has a flow control element ( 53 ) that automatically closes or releases the auxiliary oil line ( 60 ) dependent on an operation and/or assembly condition.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is U.S. bypass continuation of international patent application no. PCT/EP2012/051168, filed Jan. 25, 2012 designating the United States of America, the entire disclosure of which is incorporated herein by reference. PCT/EP2012/051168 claims priority to German patent application no. 10 2011 009 926.3, filed Jan. 31, 2011. 
     
    
     TECHNICAL FIELD 
       [0002]    The invention concerns a filtering system for motor oil of an internal combustion engine, in particular of a motor vehicle, comprising a filter head that has a feed line is for motor oil to be filtered and a discharge line for filtered motor oil and a replaceable filter that is mounted releasably by means of a rotational and/or plug connection on the filter head and that comprises a housing with at least one inlet for the motor oil to be filtered that communicates with the feed line and at least one outlet for the filtered motor oil that communicates with the discharge line and in which a filter element is arranged that separates the inlet seal-tightly from the outlet. 
         [0003]    Moreover, the invention concerns a replaceable filter of a filtering system for motor oil of an internal combustion engine that is releasably mountable by means of a rotational and/or plug connection on a filter head and that comprises a housing with at least one inlet for motor oil to be filtered and at least one outlet for filtered motor oil and in which a filter element is arranged that separates the inlet seal-tightly from the outlet. 
       BACKGROUND 
       [0004]    Filtering systems for motor oil of an internal combustion engine that are known on the market have a filter head that has a feed line for the motor oil to be filtered and a discharge line for filtered motor oil. A replaceable filter is releasably screwed onto the filter head. The replaceable filter comprises a housing with an inlet for the motor oil to be filtered and an outlet for the filtered motor oil. When the replaceable filter is mounted, the inlet communicates with the feed line in the filter head and the outlet communicates with the discharge line in the filter head. In the replaceable filter, a filter element is arranged that separates the inlet seal-tightly from the outlet and that can be flowed through by the motor oil for filtering. When the replaceable filter is mounted at a slant or vertically from above on the filter head, the residual oil contained in the filter can undesirably reach the environment, in particular the engine compartment, upon removal of the replaceable filter. 
         [0005]    The invention has the object to design a filtering system and a replaceable filter of is the aforementioned kind in which, by means of the replaceable filter, additionally an oil distribution in the filter head can be controlled. In particular, a no-drip removal of the replaceable filter should be made possible. 
       SUMMARY OF THE DISCLOSURE 
       [0006]    This object is solved according to the invention in that the filter head has an auxiliary oil line and the replaceable filter has an outflow control element that automatically closes or releases, depending on an operating and/or mounting condition, the auxiliary oil line. In particular, the outflow control element is attached in such a way on the (remaining) replaceable filter that, upon removal of the replaceable filter from the filter head, it is removed together with the replaceable filter from the filter head. Thus, in particular an outflow control element that is fast with the replaceable filter is provided. 
         [0007]    According to the invention, an auxiliary oil line is provided that is connected preferably with the feed line or with the discharge line. By means of the outflow control element, depending on the operating condition and/or the mounting condition, an oil flow into the auxiliary oil line or out of it is controlled. For characterizing the operating condition, in particular an oil temperature and/or an oil level can be used. The mounting condition relates to the mounting state of the replaceable filter at the filter head, that is wether the filter is completely and correctly mounted at the filter head. When using a replaceable filter that is not suitable and thus does not have the required outflow control element or in case of faulty or incomplete assembly, the oil flow in the auxiliary oil line is not controlled in the required way in order to preferably prevent a disruption of the internal combustion engine. The replaceable filter can be designed in a simple way in modular configuration together with the outflow control element so that the outflow control element can be exchanged and serviced together with the replaceable filter. 
         [0008]    In an advantageous embodiment, the auxiliary oil line can be an oil drain for draining motor oil from the feed line or the discharge line upon removal of the replaceable filter and the outflow control element can be provided with at least one closure element that closes the oil drain when the replaceable filter is mounted and automatically releases the oil drain when the replaceable filter is removed. When the replaceable filter is mounted, the closure element closes off the oil drain so that even in case of the internal combustion engine standing still the oil circuit cannot drain empty. The oil drain can be guided in particular to the oilpan which is arranged at the lowermost point of the internal combustion engine. As soon as the replaceable filter is removed from the filter head, the closure element automatically releases an appropriate opening of the oil drain. The residual oil that is contained in the filter head, in particular in the feed line or the discharge line, can thus drain via the oil drain. In this way, a no-drip removal of the replaceable filter is possible. 
         [0009]    In an alternative advantageous embodiment, the auxiliary oil line can be connected with an auxiliary oil circuit and the outflow control element can have at least one closure element that can be controlled depending on the operating condition and controls automatically an oil flow into the auxiliary oil circuit. The auxiliary oil circuit can contain in particular an oil radiator. In this way, depending on the operating conditions an auxiliary oil circuit can be automatically switched on or off with the outflow control element. When the correct outflow control element is not present, the auxiliary oil circuit remains open so that disturbances, in particular by overheating of the motor oil, are prevented. 
         [0010]    Advantageously, the outflow control element can have a control unit, in particular a float or a wax thermostatic element that is functionally connected with the closure element for actuation thereof. With the control unit, the operating condition can be detected and the closure element can be actuated accordingly. The outflow control element with the control unit and the closure element can be of a modular configuration and can be exchanged simply with the removal of the replaceable filter. In this way, mounting and servicing expenditure is reduced. 
         [0011]    In a further advantageous embodiment, the outflow control element can have a shaft on which the closure element is arranged and the filter head can have a shaft receptacle in which the shaft is inserted when the replaceable filter is mounted in such a way that the closure element can close off the auxiliary oil line at least partially. The shaft can be inserted simply into the shaft receptacle when mounting the replaceable filter in order to position the closure element at an opening of the auxiliary oil line. 
         [0012]    Advantageously, the outlet or the inlet of the replaceable filter can have a through opening that is coaxial to a rotational/plug-in axis of the rotational and/or plug connection and the shaft can be arranged coaxially to the rotational/plug-in axis. In this way, the shaft can be guided simply in the shaft receptacle upon opening or closing of the rotational and/or plug-in connection, in particular upon screwing in or unscrewing the replaceable filter. The shaft can be mounted outside of the through opening on a cover of the housing of the replaceable filter or can extend through the through opening. 
         [0013]    Moreover, advantageously the shaft can be connected with a central tube of the replaceable filter in a monolithic or two-part configuration, in particular by means of a snap connection. The shaft can be advantageously embodied monolithically with the central tube and can be passed through the through opening in the cover of the housing of the replaceable filter. A monolithic component can be produced in a simple and inexpensive way and is stable. A separate attachment of the shaft is not required. Alternatively, the shaft and the central tube can be of a two-part configuration. In particular, the shaft can be attached by means of a snap or clip connection on the central tube. In this way, the shaft can be separated from the replaceable filter housing and upon exchange of the replaceable filter can be re-used. This is in particular advantageous when the shaft is equipped with a complex outflow control element, in particular a temperature sensor or a float. 
         [0014]    Moreover, advantageously the shaft can be a tube whose wall has a plurality of openings. In this way, motor oil can flow into the interior of the shaft and can flow out of it. The interior of the shaft can be connected in particular with the interior of the filter element. In this way, the shaft receptacle together with the shaft can act as a part of the feed line or the discharge line in the filter head. 
         [0015]    In a further advantageous embodiment, the replaceable filter can be mounted spatially from above on the filter head. The replaceable filter can thus be mounted from above on the internal combustion engine in a space-saving way and so as to be simply accessible from the exterior. With the outflow control according to the invention, it is prevented in a simple way that residual oil can escape from the filter head upon removal of the replaceable filter. 
         [0016]    The object is solved furthermore according to the invention in that the replaceable filter has an outflow control element that, when the replaceable filter is mounted, can automatically close or release an auxiliary oil line of the filter head depending on the operating and/or mounting conditions. The advantages and features that have been mentioned above in connection with the filtering system according to the invention apply likewise to the replaceable filter according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Further advantages, features and details of the invention result from the following description in which an embodiment of the invention will be explained in more detail with the aid of the drawing. A person of skill in the art will expediently consider the features disclosed in combination in the drawing, the description and the claims also individually and combine them to meaningful further combinations. It is shown in: 
           [0018]      FIG. 1  schematically, one half in section, a filter system of an internal combustion engine with an exchangeable replaceable filter that has an outflow control element for an oil drain at a filter head; 
           [0019]      FIG. 2  schematically a longitudinal section of the replaceable filter of the  FIG. 1 ; 
           [0020]      FIG. 3  an isometric illustration of the replaceable filter of  FIGS. 1 and 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    In  FIG. 1 , a section of a filtering system  9  for motor oil of an internal combustion engine, not shown otherwise, is illustrated, showing one half in longitudinal section. A replaceable filter  10  is screwed from above onto a filter head  12  of the filtering system  9 . The replaceable filter  10  as a whole is symmetrical to a symmetry axis  13  which forms also a rotational/plug-in axis for a screw connection  15  of the replaceable filter  10  with the filter head  12 . 
         [0022]    The replaceable filter  10  comprises a cup  14  and a cover  16 . The cup  14  forms together with the cover  16  a housing  17  which substantially represents the outer geometry of the replaceable filter  10 . The cup  14  is connected by means of a fluid-tight crimp connection  18  with the cover  16 . The cup  14  comprises a closed cylindrical circumferential area which passes in the lower area of the cup  14  into a cup bottom  20 . In the area of the crimp connection  18 , a sealing groove  22  is arranged in which a seal  24  is positioned. 
         [0023]    In the cover  16 , several inlet openings  26  are provided in distribution and through which the motor oil to be purified flows into the replaceable filter  10 . The inlet openings  26  are covered on the side that is facing the interior of the cup  14  with a no-return membrane  27 . Moreover, the cover  16  has a centrally arranged tubular socket-shaped outlet  28  with an outlet opening  29  that is coaxial to the symmetry axis  13 . The outlet  28  has at its radial outer peripheral side an outer thread  30  for screw-connecting the replaceable filter  10  to a socket  32  provided with an appropriate inner thread. The outer thread  30  and the inner thread are part of the screw connection  15 . The socket  32  is part of the filter head  12 . 
         [0024]    In the interior of the housing  17  a filter element  34  is arranged such that the inlet openings  26  are seal-tightly separated from the outlet  28 . The filter element  34  comprises for this purpose a filter medium  36  which is folded in a zigzag shape and is closed to a star shape. Terminal disks  38  are arranged at the end face ends of the filter medium  36 . 
         [0025]    The terminal disk  38  that is facing the cup bottom  20  is supported by support elements  40  on the cup bottom  20 . 
         [0026]    In an opening that is provided in the terminal disk  38  facing the cup bottom  20  and that is coaxial to the symmetry axis  13 , a bypass valve  42 , not of interest in this context, is arranged which projects into the interior of the filter element  34 . 
         [0027]    In the interior of the filter element  34  there is a skeleton-like central tube  44  onto which the filter element  34  is pushed. The central tube  44  is coaxial to the symmetry axis  13  and extends between the two terminal disks  38 . 
         [0028]    A tubular shaft  46  that is coaxial to the symmetry axis  13  is extending through the outlet opening  29 . The shaft  46  is connected at one end approximately at the level of the upper terminal disk  38  by a clip connection  48  to the central tube  44 . A peripheral wall of the shaft  46  has a plurality of openings  50  through which the motor oil can flow out of the interior of the shaft  46 . At the free end of the shaft  46  a cup-shaped closure element  52  is formed whose open side faces the cover  16  of the replaceable filter  10 . The peripheral wall of the closure element  52  has several steps. The greatest diameter of the closure element  52  is located at the open side. The shaft  46  and the closure element  52  form an outflow control element  53  of the replaceable filter  10 . 
         [0029]    In the vicinity of the end faces of the closure element  52 , respectively, there is provided in the radial outer peripheral side a circumferential groove with a respective annular seal  54  and  56 . With screwed-in replaceable filter  10 , the annular seals  54  and  56  close seal-tightly relative to appropriate sealing surfaces  57  a connecting opening  58  between an oil drain  60  and a shaft receptacle  62  of the filter head  12 . 
         [0030]    The shaft receptacle  62  is part of a discharge line for filtered motor oil, not shown in detail. The shaft receptacle  62  is substantially coaxial to the symmetry axis  13 . When the replaceable filter  10  is mounted, the shaft  46  of the replaceable filter  10  is inserted into the shaft receptacle  62  in such a way that the connecting opening  58  to the oil drain  60  is closed by means of the closure element  52 . 
         [0031]    The oil drain  60  extends in a way not of interest in this connection into an oilpan that is not shown in  FIG. 1 . 
         [0032]    On the cover  16  of the replaceable filter  10  radially within the seal  24  an annular projection  64  is arranged that is coaxial relative to the symmetry axis  13  and has a U-shaped profile. The open side of the U-shaped profile is pointing away from the cup bottom  20  in axial direction. When the replaceable filter  10  is mounted, the annular projection  64  engages an appropriate annular feed groove  66  in the filter head  12 . The feed groove  66  is located also radially within the seal  24 . The seal  24  is supported on an appropriate sealing surface  67  of the filter head  12  that outwardly surrounds the feed groove  66  in radial direction. The feed groove  66  is part of a feed line for motor oil to be filtered in the filter head  12 , the feed line not further described in the following. 
         [0033]    Between the radial inner sidewall of the feed groove  66  and the radial inner exterior wall of the annular projection  64 , there is a gap  68  through which the motor oil to be filtered flows from the feed groove  66  into the inflow chamber  74  in the cover  16  and from there can flow into the inlet openings  26 . 
         [0034]    Upon operation of the internal combustion engine, the motor oil to be filtered flows from the motor oil circuit into the feed groove  66  of the feed line of the filter head  12 . From there, the motor oil flows through the gap  68  into the inflow chamber  74 . is The motor oil flows through the inlet openings  26  into the housing  17  to a radial outer raw side  70  of the filter element  34 . 
         [0035]    The motor oil to be filtered flows for filtration through the filter medium  36  radially from the exterior to the interior to a clean side  72 . The filtered motor oil passes through the opening of the skeleton-like central tube  44  into the interior of the filter element  34 . It flows towards the interior of the shaft  46  and exits the replaceable filter  10  through the outlet  28 . Through the openings  50  of the shaft  46  the filtered motor oil reaches the shaft receptacle  62  and thus the discharge line. Via the discharge line, the filtered motor oil returns into the motor oil circuit. 
         [0036]    For removal, the replaceable filter  10  is unscrewed axially relative to the symmetry axis  13  from the filter head  12 . When doing so, the shaft  46  is pulled out from the shaft receptacle  62  axially relative to the symmetry axis  13  and the closure element  52  is pulled off the corresponding sealing surfaces  57  of the connecting opening  58  of the oil drain  60 . The closure element  52  thus automatically releases the connecting opening  58  to the oil drain  60 . Residual oil which is contained in the discharge line can thus drain via the oil drain  60  into the oilpan. 
         [0037]    Simultaneous with unscrewing of the replaceable filter  10 , the annular projection  64  is moved out of the feed groove  66 . The residual oil contained in the inflow chamber  74  and still to be filtered is collected in the feed groove  66 . 
         [0038]    As a whole, residual oil possibly still contained in the inflow chamber  74 , in the feed groove  66  and in the discharge line  62  will not reach the environment upon unscrewing the replaceable filter  10  so that a no-drip removal can be realized. 
         [0039]    For mounting, the shaft  46  of the replaceable filter  10  is inserted so far into the shaft receptacle  62  that the outer thread  30  of the outlet  28  is contacting the inner thread of the socket  32 . Subsequently, the replaceable filter  10  is screwed on. When doing so, the closure element  52  automatically closes the connecting opening  58  between the shaft receptacle  62  and the oil drain  60 . In the final mounted state, the seal  24  rests seal-tightly on the sealing surface  67  of the filter head  12 . 
         [0040]    In all of the described embodiments of a filtering system  9  and of a replaceable filter  10  the following modifications are possible inter alia. 
         [0041]    The replaceable filter  10  can also be designed such that the clean side is located in radial direction outside of the filter medium  36  and the raw side is arranged within the filter medium so that the motor oil to be filtered flows in radial direction from the interior to the exterior. In this case, the shaft receptacle  62  is part of the feed line and a discharge groove corresponding to the feed groove  66  is part of the discharge line. The oil drain  60  is connected by means of connecting opening  58  with the feed line. The residual oil in the inflow chamber  74  is caught in the feed groove  66  upon removal of the replaceable filter  10 . The no-return membranes in this case are to be replaced by suitable no-return devices of a different kind. 
         [0042]    The closure element  52  can also perform further control functions. For example, the closure element can be provided with a control unit, for example, a float or a wax thermostatic element with which the closure of the connecting opening  58  can be controlled, depending on operating conditions, for example, a motor oil temperature and/or motor oil level in the drain line. 
         [0043]    In addition to the closure element  52  in or on the shaft  46 , a further control unit with a closure element for automatically closing or releasing a further auxiliary oil line, for example, of a separate oil radiator circuit, can be provided. 
         [0044]    The replaceable filter  10 , instead of being mounted from above on the filter head  12 , can also be mounted thereon at a slant from above. 
         [0045]    It is also possible to provide a different kind of filter element  34  which is provided with a differently shaped filter medium in place of the zigzag-shaped folded filter medium  36 . 
         [0046]    Instead of being connected by means of the screw connection  15 , the replaceable filter  10  can also be detachably connected on the filter head  12  by means of a different kind of rotational and/or plug-in connection, for example, a bayonet-like connection. 
         [0047]    Instead of being of a two-part configuration connected by a clip connection  48 , the shaft  46  can also be monolithically connected with the central tube  44 . 
         [0048]    Instead of being coaxial, the shaft  46  can also be eccentrically arranged relative to the symmetry axis  13  and with one end, for example, by means of a universal joint-like connection, can be attached preferably on the housing  17  of the replaceable filter  10 .

Technology Classification (CPC): 1