Abstract:
This device is intended to separate oil droplets from a gas stream and comprises an inlet wall ( 2 ) having at least one inlet opening in which there is disposed a propeller for accelerating and radially orienting the gas stream and at least one retaining wall ( 3 ) having at least one retaining medium disposed facing a propeller ( 8 ). Advantageously, the inlet wall ( 2 ) and the retaining wall ( 3 ) are linked by a hinge allowing the retaining wall ( 3 ) to be folded against the inlet wall from an unfolded production configuration to a folded use configuration.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a National Stage of PCT Application No. PCT/FR2015/053500 filed on Dec. 15, 2015, which claims priority to French Patent Application No. 14/62989 filed on Dec. 19, 2014, the contents each of which are incorporated herein by reference thereto. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention concerns a device for separating oil, intended to separate oil droplets from a gas flow, particularly for a combustion engine of a motor vehicle. 
       BACKGROUND 
       [0003]    In the operation of an inner combustion engine, it may occur a mixing phenomenon of oil droplets in a gas flow. 
         [0004]    Thus, an engine conventionally comprises a combustion chamber into which a gas mixture of fuel and air is admitted. In operation, it happens that a part of the combustion gases is infiltrated between the piston and the cylinder in the oil pan of the engine. These gases, called crankcase gases, can damage the engine. It is thus known to evacuate and reuse them by recycling them in the gas mixture. However, the evacuated crankcase gases are charged with suspended oil droplets collected in the crankcase. These oil droplets clog the elements of the engine crossed by the crankcase gases, in particular the air inlet line. Furthermore, they contribute to the oil consumption. Finally, taking into account the increasingly drastic anti-pollution standards, it has become necessary to purify the air entering the composition of the gas mixture by eliminating in particular the suspension oil droplets for the best possible combustion. 
         [0005]    It is thus known from the patent documents EP 1 684 888 or WO 2010142544 to eliminate the oil droplets transported by the crankcase gases with an oil separation device allowing settling the oils droplets. 
         [0006]    However, the known oil separation devices are complex to produce, in particular because of the large number of their components. 
       BRIEF SUMMARY 
       [0007]    In this technical context, it is an object of the invention to propose an oil separation device which has an important capability for capturing oil droplets and which has a controlled production cost. 
         [0008]    The invention concerns an oil separation device intended to separate oil droplets from a gas flow, comprising an inlet wall having at least one inlet orifice in which is disposed a helix allowing accelerating and orienting radially the gas flow and at least one retention wall having at least one retention media disposed opposite to a helix. 
         [0009]    Thus, the invention provides a device producing an important oil droplet capture while including few parts and being space saving. 
         [0010]    According to a preferred embodiment of the invention, the inlet wall and the retention wall are linked by a hinge allowing the retention wall to be folded over the inlet wall from an unfolded configuration of production to a folded configuration of use. 
         [0011]    This disposition of the invention allows a particularly efficient manufacturing of the invention because the device as a whole can be produced by a single molding operation. 
         [0012]    Advantageously, the inlet wall comprises a cylindrical wall delimiting an inlet orifice in which a helix is disposed, said helix having a central cone of which blades extend, the blades joining the cylindrical wall. 
         [0013]    This characteristic of the invention allows carrying out the acceleration and the radial orientation of the flow, on the one hand, without a movable part and, on the other hand, in a reduced space requirement. 
         [0014]    In an embodiment of the invention, the device comprises an intermediate wall interposed between the inlet wall and the retention wall, the intermediate wall having openings intended to be in alignment with at least one helix to direct the gas flow to the retention media. 
         [0015]    Preferably, the intermediate wall is linked to the inlet wall by a hinge for simplification purpose of the manufacturing operations. 
         [0016]    According to a possibility, the retention wall is solid. 
         [0017]    According to another possibility, the retention wall has a recess. 
         [0018]    In a variant, the retention media panel is disposed in the vicinity of retention wall. 
         [0019]    In an embodiment of the invention, the retention wall has at least one cage into which a retention media is inserted, said cage being disposed in the axis of a helix when the device is in a folded configuration of use. 
         [0020]    According to a possibility, the retention media has the shape of a cylinder of radial retention media inserted into the cage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    For its good understanding, the invention is described with reference to the appended drawings showing, by way of non-limiting examples, several embodiments of oil separation devices according to the invention. 
           [0022]      FIG. 1 , shows in perspective a first embodiment of an oil separation device prior to its shaping 
           [0023]      FIGS. 2 and 3  show in perspective the separation device of  FIG. 1  in the configuration of use 
           [0024]      FIG. 4  shows in perspective a variant of an oil separation device  1  with oil prior to its shaping, 
           [0025]      FIG. 5  shows a variant of an oil separation device in the configuration of use, 
           [0026]      FIGS. 6 to 11  show in cross-section another embodiment of the invention in several variants. 
       
    
    
       [0027]    By convention, the elements of the invention which are found in different embodiments bear the same numerical references. 
       DETAILED DESCRIPTION 
       [0028]      FIG. 1  shows in its unfolded configuration of production an oil separation device  1 . 
         [0029]    As visible in this figure, the separation device  1  according to the invention is in the shape of a unitary plastic element and includes essentially three portions linked in pairs. 
         [0030]    In practice, the separation device  1  is made of molded plastic and can be obtained in a single molding operation. 
         [0031]    At the center of the separation device  1  is located an inlet wall  2 . On the other side of the inlet wall  2 , the separation device  1  is equipped with a retention wall  3  and an intermediate wall  4 . The retention  3  and intermediate  4  walls are linked to the inlet wall  2  by film hinges that is to say a bridge made of thinned material which allows the intermediate wall  4  and the retention wall  3  to pivot relative to the inlet wall  2 . It should be noted that the retention wall  3  is linked to the inlet wall  2  by a strip made of material  5  itself linked to the retention wall  3  and to the inlet wall  2  by film hinges made of thinned material. As visible in  FIGS. 1 to 5 , the retention wall  3  is further provided with a material return  6 . 
         [0032]    The structural characteristics and functions of the different portions will appear below. 
         [0033]    It can be perceived in  FIGS. 1 to 5  that the inlet wall  2  is provided with nine helices  8  disposed, in this embodiment, in rows of three. 
         [0034]    Within the meaning of the present document, helix means a fixed member allowing accelerating axially and radially an air flow of oil droplets with the aim of centrifuging the oil particles and causing their coalescence. 
         [0035]    The inlet wall  2  is provided with inlet orifices  9  delimited by a cylindrical wall  10  within which a helix  8  is positioned. The helix  8  has a central cone  12  from which blades  13  extend, which join the cylindrical wall  10 . 
         [0036]    The intermediate wall  4  is provided with openings  16  which are disposed in the extension of the inlet orifices  9 . The retention wall  3  is in the shape of a wall having a recess  15  (see  FIGS. 1 to 3 ) or a solid wall (see  FIGS. 4 and 5 ) on which a retention media panel  14  is disposed. The retention media is, for example, a media called coalescent media, that is to say it allows collecting oil droplets being suspended in an air flow. The retention media can comprise in particular a fiber-based porous material. 
         [0037]    In practice, the separation device  1  is made by molding, the inlet wall  2 , the retention wall  3  and the intermediate wall  4  being substantially in the extension of each other. 
         [0038]    The retention media panel  14  is attached on the retention wall  3 . 
         [0039]      FIGS. 2 and 3  show the separation device  1  in its folded configuration of use. In this configuration, the intermediate wall  4  is folded over the inlet wall  2  and the retention wall  3  is folded over the intermediate wall  4 . It is possible to expect that one of the walls is provided with pins  17  which are inserted into bores  18  formed in an adjacent wall to manage the proper positioning of the walls relative to each other. 
         [0040]    It will thus be understood that the separation device  1  is assembled in an extremely simple manner. The assembly can be performed in a manual or robotic manner without requiring expensive installation. 
         [0041]    The separation device  1  can be inserted into a heat engine to trap the oil droplets present in an air flow such as for example in a crankcase gas flow. 
         [0042]      FIGS. 6 to 11  partially show another embodiment of a separation device  1  with an inlet wall  2  and a retention wall  3 . 
         [0043]    The inlet wall  2  is therefore equipped with a helix  8 . 
         [0044]    The inlet wall  2  is provided with inlet orifices  9  delimited by a cylindrical wall  10  within which is a helix  8  positioned. The helix  8  has a central cone  12  from which blades  13  extend. 
         [0045]    The retention wall  3  is folded and is pressed against the inlet wall  2 . The function of the retention wall  3  is to trap the oil droplets present in the gas flow. 
         [0046]    The retention wall  3  has an opening  16  possibly bordered by a rib  17  and topped by a cage  19 . As it will appear, the function of the cage  19  is to receive a retention media. For this, the cage  19  comprises spacers  21  which support a posterior face. 
         [0047]    In the embodiments of  FIGS. 6 and 7 , the retention media is in the shape of a disk  22  positioned in a plane normal to the turbine axis. 
         [0048]    In the embodiment of  FIG. 6 , the posterior face of the cage is constituted by a spider  23 . The axial retention media disk  22  is accordingly blocked against the spider  23 . The axial retention media disk  22  can be equipped, at its periphery with notches  24  in which the spacers  21  are engaged. 
         [0049]      FIG. 7  shows a variant of the separation device  1  illustrated in  FIG. 6  in which the axial retention media disk  22  is held by a wall  26  which forms the posterior wall of the cage  19 . The wall  19  forms a bearing surface for the axial retention media disk  22 . 
         [0050]      FIGS. 8 and 9  illustrate two variants in which the separation device  1  is equipped with a radial retention media. 
         [0051]    As shown in these Figures, the separation device  1  is equipped with a cylinder of radial retention media  27 . The cylinder of radial retention media  27  is interposed between the inlet wall  2  and the retention wall  3 . In practice, the cylinder of radial retention media  27  is clamped between a rib  29  coming from the inlet wall  2  and the rib  17  of the retention wall  3 . The cylinder of radial retention media  27  has a height substantially equal to the height of the spacers  21  of the intermediate wall  4 . 
         [0052]    In a variant illustrated in  FIG. 9 , the cylinder of radial retention media  27  is encapsulated in a cylinder  29  made of plastic which comes from the intermediate wall  4 . In this variant, the cylinder  19  made of plastic material delimits a posterior opening through which flows the air flow cleared of its oil droplets. 
         [0053]      FIGS. 10 and 11  show two variants in which the separation device  1  combines an axial retention media disk  22  and a cylinder of radial retention media  27 . 
         [0054]    As shown in these figures, the separation device  1  comprises an inlet wall  2  equipped with a helix  8  allowing accelerating and orientating radially the air flow charged with oil droplets. 
         [0055]    The retention wall  4  is equipped with an axial retention media disk  22  and a cylinder of radial retention media  27 . The cylinder of radial retention media  27  is clamped between a rib coming from the inlet wall  2  and a rib coming from the intermediate wall  4 . The axial retention media disk  22  is held at the bottom of the cage  19 . 
         [0056]    The length of the cylinder of radial retention media  27  is such that a space  30  is formed between the cylinder of radial retention media  27  and the axial retention media disk  22 . This space  30  allows the air flow cleared of its oil droplets to escape from the separation device  1 . 
         [0057]    This embodiment of the invention carries out a combination of a radial retention of the oil droplets which are orientated radially upon leaving the helix  8  and an axial retention of the oil droplets which are accelerated upon leaving the helix. 
         [0058]      FIG. 11  is a variant of the separation device  1  of  FIG. 9  in which the cage  19  into which the retention media is inserted, is solid and in which the posterior face of the cage is also solid. 
         [0059]    The invention is not limited to the embodiments described above by way of non-limiting examples, but it encompasses all embodiments thereof. Thus, it is considered to produce the inlet wall, the retention wall and the intermediate wall separately and to assemble them in a subsequent operation.