Patent Publication Number: US-2022220872-A1

Title: Blow-by gas filtration assembly with support and control shaft

Description:
FIELD OF APPLICATION 
     The present invention relates to a blow-by gas filtration assembly. 
     In particular, the blow-by gas filtration assembly of the present invention is fluidly connectable to the crankcase ventilation circuit of an internal combustion engine system inside of a vehicle to receive blow-by gases (from said crankcase) and filter from them the suspended particles contained therein. 
     Specifically, “blow-by gas” means oil vapours vented from the crankcase of an internal combustion engine during its operation. In particular, said blow-by gases have a composition similar to that of exhaust gases and are generated by combustion of the air/fuel mixture in the combustion chamber. Instead of reaching the exhaust gas emission circuit, these gases leak into the lower portion of the crankcase, passing alongside the cylinders and bringing carbon particles and oil drops with them. In the present discussion, for the sake of simplicity, blow-by gases are considered to consist of air and suspended particles; said suspended particles comprise oil droplets and/or carbonaceous particulates. 
     STATE OF THE ART 
     In the state of the art, solutions of filtration assemblies that is fluidly connectable to the crankcase and suitable for venting it from blow-by gases are known of. 
     Specifically, blow-by gas filtration assembly solutions which separate unwanted suspended particles from the aforesaid blow-by gases are known of, comprising a filter group having such purpose. 
     In the state of the art, a plurality of embodiments of filtration assemblies are known: for example, a first type provides for the presence of a filter group comprising a porous filter medium suitable for filtering blow-by gases when crossed by them; a second type provides for the presence of a filter group comprising a plurality of discs mutually spaced apart and guided in rotation, in which by the action of the centrifugal force the suspended particles are separated from the air; a third type which provides for the combination of the first two types, in which, in fact, a porous filter medium is provided that is guided in rotation. 
     In this context, with particular reference to the aforementioned third preferred embodiment, the known solutions are particularly complex and difficult to assemble (and disassemble). 
     SOLUTION ACCORDING TO THE INVENTION 
     In the aforesaid state of the art the need is therefore strongly felt to have a blow-by gas filtration assembly that solves the aforesaid problem, being simple in shape and above all requiring simple assembly (and disassembly). 
     The purpose of the present invention is to provide a new improved embodiment of a blow-by gas filtration assembly satisfying said requirement. 
     Such purpose is achieved by the blow-by gas filtration assembly claimed in claim  1 . The dependent claims show preferred embodiment variants having further advantageous aspects. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the invention will, in any case, be evident from the description given below of its preferred embodiments, made by way of a non-limiting example with reference to the appended drawings, wherein: 
         FIG. 1  shows a perspective view in separate parts of the blow-by gas filtration assembly of the present invention, according to a preferred embodiment; 
         FIGS. 2 a  and 2 b    respectively show two perspective views in separate parts of the blow-by gas filtration assembly of the present invention; 
         FIG. 3  shows a longitudinal cross-section view of the blow-by gas filtration assembly assembled and shown in the preceding figures; 
         FIGS. 4 a  and 4 b    are two cross-section views respectively along the cross-section planes V-V and VI-VI shown in  FIG. 3 ; 
         FIG. 4 ′ is an enlargement of the area A shown in  FIG. 4   a;    
         FIGS. 5 a , 5 b , 5 c , 5 d , 5 e , 5 f , 5 g    show the various assembly steps of the blow-by gas filtration assembly according to the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the appended drawings, reference numeral  1  denotes a blow-by gas filtration assembly suitable for performing a filtration/separation action on particles (liquid and/or solid) suspended in the gas stream. 
     Said blow-by gas filtration assembly  1  is fluidly connectable to a crankcase ventilation circuit of an internal combustion engine of a vehicle to receive blow-by gases and filter from them the suspended particles contained therein returning a stream of clean gas (i.e. filtered) to other vehicle systems such as, for example, to the engine air intake circuit communicating with the combustion chamber of the internal combustion engine. 
     Preferably, said blow-by gas filtration assembly  1  can be directly assembled to the crankcase of an internal combustion engine of a vehicle. In particular, the present invention is not limited to this feature; the blow-by gas filtration assembly  1  could be configured as a stand-alone device comprising respective inlet and outlet ports communicating respectively with the crankcase, for receiving blow-by gases to be filtered, and with the air intake circuit, for recirculating the gas stream filtered of solid and liquid particles towards the combustion chamber. 
     According to the present invention, the filtration assembly  1  comprises an X-X axis with respect to which the components described below extend or are positioned. 
     According to the present invention, the blow-by gas filtration assembly  1  comprises a main body  2 . Preferably, the other components of the system are positioned in or on said main body  2 , as described extensively below and evident from the exemplary figures attached below. 
     In particular, the main body  2  comprises a filtration chamber  20  in which filtration/separation operations of the blow-by gases take place. The filtration chamber  20  is therefore fluidly connected to the crankcase ventilation circuit of an internal combustion engine of a vehicle to receive dirty blow-by gases, i.e. comprising suspended particles (solid and/or liquid), and emit clean blow-by gases, i.e. cleaned of suspended particles, into the engine air intake system. 
     According to a preferred embodiment, the main body  2  comprises respective blow-by gas inlets and outlets. 
     In particular, the main body  2  comprises an inlet mouth  21  (not shown) fluidly connected with the crankcase ventilation circuit of a vehicle to receive blow-by gases to be filtered. Preferably, said inlet mouth  21  is made substantially parallel to the X-X axis spaced therefrom. Preferably, said inlet mouth  21  is made on the side wall of the main body  2 . Preferably, said inlet mouth  21  is made on the wall of the main body  2  defining the filtration chamber  20 . 
     The main body  2  comprises an outlet mouth  22 . Said outlet mouth  22  is made positioned on the X-X axis. preferably, the outlet mouth  22  is perpendicular to said X-X axis. Preferably, the outlet mouth  22  is coaxial to the X-X axis. 
     The outlet mouth  22  is bounded laterally, annularly, by an outlet edge  220 . 
     According to a preferred embodiment, from the outlet mouth  22 , the main body  2  provides for an outlet connection that interfaces with the engine air intake circuit communicating with the combustion chamber of the internal combustion engine of a vehicle. According to a preferred embodiment, said outlet connection communicates with an outlet opening made on the coupling flange of the main body  2  to the internal combustion engine crankcase. 
     According to a preferred embodiment, moreover, the main body  2  comprises an insertion opening  25  through which the components described below can be inserted inside the main body  2 , preferably inside the filtration chamber  20 . Said insertion opening  25  is made in a position opposite the outlet mouth  22 . Preferably, the insertion opening  25  is made along the X-X axis having its extension (orientation) parallel to the outlet mouth  22 . Preferably, the insertion opening  25  is defined laterally, annularly, by an insertion edge  250 . 
     Preferably, the insertion edge  250  and the outlet edge  220  are respectively concentric with respect to the X-X axis. Preferably, the insertion opening  25  defines a larger opening of the outlet mouth  22  so as to allow and facilitate the insertion operations of the various components. 
     According to the present invention, the blow-by gas filtration assembly  1  comprises a filter group  3 , housing and operating in said filtration chamber  20 , specifically suitable for performing said filtration/separation operations of the particles suspended in blow-by gases. 
     The filter group  3  extends along the X-X axis having a hollow cylindrical shape, comprising, in fact, a central chamber  300 . 
     The filter group  3  can be crossed radially by blow-by gases. Preferably, the filter group  3  can be crossed by blow-by gases in a radial direction from the outside towards the inside. 
     Preferably, the inlet mouth  21  is radially facing the filter group  3 . According to a preferred embodiment, the inlet mouth  21  is radially facing the outer surface of the filter group  3 . 
     Preferably, the outlet mouth  22  is axially facing the central chamber  300 . 
     In other words, the filter group  3  identifies, in the filtration chamber  20 , a dirty side in which there are blow-by gases to filter and a clean side in which there are filtered blow-by gases. Preferably, the outlet mouth  22  is fluidly connected with said clean side. 
     According to a preferred embodiment, the central chamber  300  of the filter group surrounds the clean side in which the filtered blow-by gases are present and fluidly communicates with the outlet mouth  22 . 
     According to a preferred embodiment, the filter group  3  comprises a filter medium  30 . The filter medium  30 , which can be crossed radially comprises a non-woven fabric pleated in the form of a star or a porous cylindrical septum. 
     Moreover, according to a preferred embodiment, the filter group  3  comprises two filter plates  31 ,  32  arranged at the ends of the filter medium  30 . 
     In addition, according to a preferred embodiment, the filter group  3  comprises a central structure  33  which is housed inside the filter medium  30  and joins the two filter plates  31 ,  32 , so that the filter plates  31 ,  32  are integrally connected in rotation. Preferably, said central structure  33  has a plurality of through openings suitable to allow the passage of the fluid being filtered. 
     As shown in the attached figures, the central chamber  300  extends through the filter plates  31 ,  32  surrounded by the filter medium  30 . 
     According to a preferred embodiment, the central chamber  300  extends through respective through openings  310 ,  320  made on the filter plates  31 ,  32 . Preferably, said openings  310 ,  320  are concentric to the X-X axis, like the central chamber  300 . 
     According to the present invention, moreover, the filtration assembly  1  comprises an engine group  4  operatively connected to the filter group  3  to command it in rotation about the X-X axis. 
     According to the present invention said engine group  4  comprises a rotor  41  and a stator  42 . The electrical actuation of the stator  42  results in rotation of the rotor  41 . Preferably, the rotor  41  is housed in a rotor chamber  420  surrounded by the presence of the stator  42 . Preferably, the rotor  41  is at least partially housed in the rotor chamber  420  surrounded by the presence of the stator  42 . 
     According to a preferred embodiment, the engine group  4  is of the electric type, preferably brushless. 
     According to a preferred embodiment, the rotor  41  is a toroid in ferromagnetic material. Preferably, the rotor  41  is a permanent magnet. 
     According to a preferred embodiment, the rotor  41  comprises one or more elements in ferromagnetic material arranged in the shape of a toroid. 
     According to a preferred embodiment, the stator  42  comprises a plurality of energizable magnetic poles for generating a rotating magnetic field. Preferably, said rotating magnetic field is suitable to interact with the rotor to determine its rotation around its axis and thus determine the rotation of the shaft  5  and therefore of the filter group  3 . 
     Preferably, further, the engine group  4  comprises an engine body  40  housing the stator  42  in which a rotor chamber  420  is defined in which the rotor  41  is housed. Preferably, the engine body  40  can be sealingly fitted to the main body  2 . 
     Preferably, the engine body  40  sealingly engages the main body  2  to close the insertion opening  25 . The engine body  40  can in fact be mounted axially to the main body  2 . 
     According to a preferred embodiment, the engine group  4  comprises an electronic board electrically connected to the vehicle controller by means of an electrical connector integrated on the engine body  40 . 
     Preferably, said electronic board is electrically connected to a series of windings provided on the stator, suitable for energizing the magnetic poles of the stator to establish a rotating magnetic field flow, determining the rotation of the rotor  41  and thus of the shaft  5  and of the filter group  3 . 
     According to the present invention, the blow-by gas filtration assembly  1  comprises a support and control shaft  5 . 
     Such shaft  5  is a hollow body extending along the X-X axis and is specially designed to be operatively connected to the filter group  3  and the engine group  4 . The shaft  5  extends in length both inside the filtration chamber  2  and inside the engine group  4 , inside the rotor chamber  420 . 
     Preferably, the shaft  5  is a hollow body made as a single component. 
     According to an alternative embodiment, the shaft is a hollow body composed of two or more parts mechanically connectable with each other (e.g. by welding, mechanical couplings, screws or the like) reversibly or irreversibly so as to form a single component, the constituent parts of which rotate synchronously, both with the filter group  3  and with the rotor  41 . 
     The shaft  5  in fact comprises an engine portion  51  on which the rotor  41  is housed and a filter portion  52  on which the filter group  3  is housed. In particular, the rotor  41  and the filter group  3  are mounted integrally to the shaft  5  respectively to the engine portion  51  and to the filter portion  52  in such a way that a controlled rotation of the rotor  41  corresponds to a rotation of the shaft  5  and thus of the filter group  3 . In particular, in the present description, “integrally” means that the rotor  41  and the filter group  3  are mechanically connected to the shaft  5  to rotate in unison (or synchronously). Preferably, the rotor  41  and/or the filter group  3  are reversibly (i.e. detachable from) and/or irreversibly (i.e. constituting a single component) engaged to the shaft. 
     According to a preferred embodiment, the filter group  3  and the filter portion  52  are mutually engaged by a shape coupling respectively comprising along the X-X axis at least a first notch  308  and a first protrusion  528  housed in said first notch  308 . Preferably, the first notch  308  is located on the filter group  3  in the central chamber  300  and the first protrusion  528  is made on the shaft  5  protruding from it radially, or vice versa. According to a preferred embodiment, there are a plurality of first notches  308  and subsequent first protrusions  528  (mutually angularly equispaced). 
     According to a preferred embodiment, one or more (preferably two) retaining protrusion elements  309  are made at the sides of the first notch  308 . Preferably, the retaining protrusion elements  309  protrude radially relative to the first notch  308 . According to a preferred embodiment, such retaining protrusion elements  309  comprise one or more protrusions protruding radially in the opposite direction to that of the first notch  308 . 
     According to a preferred embodiment, on the sides of the first protrusion  528  are one or more (preferably two) safety housings  529  in which the retaining protrusion elements  309  are housed. Preferably, the first protrusion  528  protrudes radially relative to the safety housings  529 . 
     Preferably, therefore, the retaining protrusion elements  309  housed in the respective safety housings  529  retain the first protrusion  528  in the respective first notch  308 , preventing an undesirable exit therefrom. According to a preferred embodiment, such safety housings  529  comprise one or more recesses made radially in the opposite direction to that of the first protrusion  528 . 
     In other words, according to a preferred embodiment, the retaining protrusion elements  309  and the respective safety housings  529  are intended to act as safety means to prevent the unwanted release of the connection provided between the filter group  3  and the shaft  5  during their rotation. 
     According to a preferred embodiment, the rotor  41  and the engine portion  51  are mutually engaged with a shape coupling comprising respectively along the X-X axis at least a second notch  418  and a second protrusion  518  housed in said second notch  418 . Preferably, the second notch  418  is located on the rotor  41  and the second protrusion  518  is made on the shaft  5  protruding from it radially, or vice versa. According to a preferred embodiment, there are a plurality of second notches  418  and subsequent second protrusions  518  (mutually angularly equispaced). According to the present invention, further, the filter portion  52  (of the shaft  5 ) comprises inside it an outlet duct  520  of the filtered blow-by gases inside which said the outflow of said filtered blow-by gases towards the outlet mouth  22  takes place. In other words, the shaft  5  is a hollow body the cavity of which forms at least partially the outlet duct  520  of the filtered blow-by gases. 
     In other words, the outlet duct  520  connects the clean side (of the filter group  3 ) to the outlet mouth  22 . In yet other words, the blow-by gases already subjected to filtration operations flow out into the outlet duct  520 . 
     Preferably, the outlet duct  520  fluidly connects the central chamber  300  of the filter group  3  to the outlet mouth  22 . 
     According to a preferred embodiment, the filter portion  52  is fluidly connected with the central chamber  300  and the outlet mouth  22  to make the filtered blow-by gases flow out. 
     Preferably, the shaft  5  comprises a duct outlet  522 , which fluidly connects the inside of the outlet duct  520  and the outlet mouth  22 . The duct outlet  522  is positioned at an axial end of the shaft  5 . Preferably, the duct outlet  522  is positioned at the outlet mouth  22 . Preferably, the duct outlet  522  is placed on the shaft  5  at the end of the filter portion  52 . Preferably, the duct outlet  522  is positioned on the shaft  5  at the axial end of the filter portion  52  distal from the engine portion  51 . According to a preferred embodiment, the shaft  5  comprises an internal diffuser  525 , housed in the outlet duct  520  in an axially distal position from the duct outlet  522 . 
     Preferably, the internal diffuser  525  is suitable to direct the flow of filtered blow-by gases towards the duct outlet  522 . 
     In particular, the internal diffuser  525  housed in the outlet duct  520  closes the outlet duct  520  at the opposite end of the duct outlet  522  directing the output of filtered gases. 
     Preferably, the internal diffuser  525  has a substantially tapered shape in the direction of the duct outlet  522 . 
     Preferably, the internal diffuser  525  has a substantially conical, or pyramidal shape, having the apex proximal to the duct outlet  522  and the base distal from the duct outlet  522 . 
     According to a preferred embodiment the filter portion  52  comprises a plurality of longitudinal slots  521  through which filtered blow-by gases flow into the outlet duct  520 . Preferably, the longitudinal slots  521  are mutually angularly equidistant. 
     According to a preferred embodiment, the shaft  5  comprises an abutment ring  53  axially positioned between the engine portion  51  and the filter portion  52 . 
     Preferably, the abutment ring  53  extends in a radial direction and provides an axial abutment and a support to the filter group  3 . 
     According to a preferred embodiment, the filter group  3  is axially inserted above said abutment ring  53 . Preferably, the filter group  3  is engaged to the abutment ring  53 . Preferably, the filter group  3  sealingly engages the abutment ring  53 . 
     According to a preferred embodiment, the blow-by gas filtration assembly  1  comprises a first support bearing  6  fitted on the shaft  5  to support the shaft  5  to the main body  2  and/or the engine body  40 . 
     Preferably, the first bearing  6  is axially fitted on the engine portion  51 . 
     Preferably, the first bearing  6  is axially fitted on the engine portion  51  of the shaft  5  in an axial position between the rotor  41  and the filter portion  52 . 
     Preferably, the first bearing  6  is axially fitted on the engine portion  51  of the shaft  5  in an axial position between the rotor  41  and the abutment ring  53 . 
     According to a preferred embodiment, the first bearing  6  separates the rotor chamber  420  from the filtration chamber  20 . 
     According to a preferred embodiment, the first bearing  6  closes the filtration chamber  20  tight. 
     Preferably, the first bearing  6  engages the engine body  40  and seals the rotor chamber  420  tight, dividing it from the filtration chamber  20 . 
     Preferably, the first bearing  6  engages the main body  2  and seals the filtration chamber  20 , dividing it from the rotor chamber  420 . In other words, the first bearing  6  engages the engine body  40  and seals the rotor chamber  420  so that only air is present inside the rotor chamber  420 . 
     According to a preferred embodiment, the blow-by gas filtration assembly  1  comprises a second bearing  7 , for support, which can be fitted on the shaft  5  to support the shaft  5  to the main body  2 . 
     Preferably, by means of the first bearing  6  and the second bearing  7  the shaft  5  is positioned along the X-X axis. Preferably, by means of the first bearing  6  and the second bearing  7  the shaft axis  5  is aligned with the X-X axis. 
     The present invention is not limited to the shape or type of the first and second bearings; preferably, the term “bearing” means a sliding bearing, a ball bearing, or a bushing. 
     According to a preferred embodiment, the second bearing  7  is positionable on the filter portion  52  in an axial position distal from the engine  4 . 
     According to a preferred embodiment, the second bearing  7  is positionable on the main body at the outlet mouth  22 . 
     According to a preferred assembly method, the second bearing  7  is installed at the outlet mouth  22  prior to the other components, in particular the filter group  3  and the engine group  4 . 
     Preferably, the second support bearing  7  seals the filtration chamber  20  tight. According to a preferred embodiment, the second support bearing  7  engages the outlet edges  220  defining the outlet mouth  22 . 
     According to a preferred embodiment, the second bearing  7  seals the filtration chamber engaging the outlet edges  220  defining the outlet mouth and the filter portion  52  (preferably in a portion thereof proximal to the shaft end). 
     Preferably, the first bearing  6  and the second bearing  7  have the same dimensions (having the same diameter of the inner hole designed to come into contact with the outer surface of the shaft  5  and outer diameter designed to come into contact with the respective housing seat). 
     According to a preferred embodiment, the engine portion  51  of the shaft  5  is also hollow. 
     According to a preferred embodiment, the shaft  5  is made of thermoplastic material obtained by means of a single moulding operation. 
     Preferably, the shaft  5  is made of polyphenylene sulphide (PPS). 
     Preferably, the shaft  5  is made of a polyphenylene sulphide (PPS) based material. 
     Preferably, the shaft  5  is made of a polyphenylene sulphide (PPS) based material reinforced with fibreglass (PPS+GF15, PPS+GF30, PPS+GF40). 
     Preferably, the shaft  5  is made of a nylon-based material (PA, PA 6, PA 6.6 or a mixture thereof). 
     Preferably, the shaft  5  is made of nylon-based material reinforced with fibreglass. (PA+GF, PA 6.6+GF35, PA 6+PA 6.6+GF 35) 
     Preferably, the shaft  5  is made of a material comprising a polyamide-based compound (e.g. PPA). 
     According to a preferred embodiment, the shaft  5  is made of a metallic material. Preferably, the shaft  5  is made of aluminium alloy. 
     According to a preferred embodiment the filter plates  31 ,  32  sealingly engage the shaft  5  by means of a first annular gasket  315  and a second annular gasket  325 . 
     Preferably, said first annular gasket  315  is a radial gasket. Preferably, said second annular gasket  325  is a radial gasket. Preferably, said first annular gasket  315  engages the abutment ring  53 . Preferably, said second annular gasket  325  engages the filter portion  52  of the shaft  5  in a region between the longitudinal openings  521  and the duct outlet opening  522 . 
     As shown in  FIGS. 5 a  to 5 f   , provided by way of example, the assembly operations are extremely simplified, providing for the axial insertion of the various components onto the shaft and then the axial insertion of the group of components thus assembled in the main body. 
     Innovatively, the blow-by gas filtration assembly of the present invention widely fulfils the purpose of the present invention by presenting itself in a simple form and above all requiring simple assembly and disassembly operations. 
     Advantageously, the shaft is suitable for supporting and rotating the filter group. Advantageously, the shaft is also suitable to direct and facilitate the outflow of the filtered blow-by gases towards the outlet mouth. 
     Advantageously, the use of a shaft comprising a specific filter group support portion and a specific rotor support portion reduces the costs associated with the production of the filtration assembly by eliminating any alignment and/or compensation elements provided between the engine group and the filter group. 
     Advantageously, the shaft comprising the portions supporting the rotor and filter group allows a more compact filtration assembly to be built, providing, with equal dimensions, spaces which can be used to increase the filtering surface of the filter group, improving the filtering performance of the assembly. Advantageously, in particular, the blow-by gas filtration assembly is extremely compact both in the axial (longitudinal) dimension and, above all, in the radial dimension. 
     Advantageously, in a configuration with a filter group operating radially from the outside towards the inside, any gas recirculation inside the filtration chamber is minimized and the circulation of the filtered gases towards the outlet mouth and the intake of the gases to be filtered from the engine crankcase to the filtration chamber itself is favoured. 
     Advantageously, the shaft is a multifunctional component. Advantageously, the outlet duct of the filtered blow-by gases, the portions for supporting the filter group and the fluid coupling of said group to the outlet duct, the portions for supporting the rotor and the first bearing for supporting the shaft to the engine body and/or the main body are respectively provided in the shaft. Advantageously, the shaft is a hollow body, i.e. it is made at least partially in a hollow shape, reducing the weight of the filtration assembly, the consumption associated with the operation of the filtration assembly and the mechanical stresses on the parts (engine, bearings) responsible for keeping the filter group in rotation. 
     Advantageously, the shaft can be made in a single body eliminating any joints or interconnections between parts offering a simple solution, with greater structural strength able to ensure compliance with stricter dimensional and geometric tolerances. 
     Advantageously, the shaft (and thus the filter group) is easy to position in an axially aligned position, in particular aligned with the electric motor in particular with the rotation axis of the rotor. 
     Advantageously, the shaft ensures the alignment between the rotation axis of the rotor and the rotation axis of the filter group, reducing unwanted power consumption and minimizing the electricity consumption required by the vehicle for the operation of the filtration assembly. 
     Advantageously, the respective components, i.e. the rotor and the filter group, can be simply fitted onto the respective portions on the shaft. 
     Advantageously, the shaft is coupled to the outlet mouth by means of a bearing, reducing the friction generated by the rotation of the shaft and the components installed thereon, offering a better use of the available electricity or even a reduction in the electricity required of the electric motor. 
     Advantageously, the shaft is coupled on one side to the electric motor and on the other to the main body by means of respective bearings mounted at the opposite ends of the filter group, ensuring optimal alignment between the rotation axis of the rotor and the outlet mouth with respect to the adoption of sliding gaskets and at the same time reducing the friction caused by rotation. 
     Advantageously, the use of bearings ensures that coupling and sealing systems with a greater chemical resistance to the negative effects of blow-by gases are used instead of the adoption of gaskets which are more sensitive to wear and ageing phenomena. 
     Advantageously, the filter group is simple to fit/remove from the shaft, thus facilitating the assembly and maintenance of the filtration assembly. 
     Advantageously, the blow-by gas filtration assembly is extremely effective in the action on said blow-by gases thanks to the combined action of the filter group that filters the solid particles and above all agglomerates the suspended oil particles that are subsequently subjected to the centrifugal rotation action. 
     Advantageously, the use of a filter group with a porous filter medium rotated by the electric engine by means of said shaft allows effective filtration of blow-by gases at lower rotational speeds (3000 rpm) compared to separators equipped with discs/centrifuges operating at much higher speeds (10000 rpm), thus reducing the electricity consumption and also the acoustic emissions produced by the filtration assembly. 
     Advantageously, with a single operation in the axial direction, the various components are inserted into the main body and the blow-by gas filtration assembly is quickly ready for use. 
     Advantageously, with a minimum number of seals, the potential problem of blow-by gas leakage is remedied. 
     Advantageously, the shaft supports the bearing separating the rotor chamber from the filtration chamber to prevent and/or minimize the circulation of blow-by gases in the rotor chamber. Advantageously, in this way the accumulation of contaminants inside the rotor chamber is minimized ensuring optimal propagation of the magnetic field between stator and rotor and maintenance of the gap between stator and rotor useful for ensuring the free movement of the rotor with the lowest level of friction and dissipation. 
     Advantageously, the rotor remains contained inside the rotor chamber so that the engine portion of the shaft is not affected by the gas circulation, ensuring effective protection of the components of the electric motor from wear and degradation due to the accumulation of contaminants included in the blow-by gases. Advantageously, the shaft and rotor do not require periodic maintenance/replacement, but can be used for the entire service life envisaged for the filtration assembly, even if the filter group requires periodic replacement. 
     Advantageously, the filter group requires a minimum number of sealing elements, for example, a single gasket, possibly two gaskets, is sufficient. 
     Advantageously, the engine body of the electric motor can be fixed and sealingly coupled to the walls of the main body. Advantageously, the electric motor can be made as a stand-alone module that can be coupled after the filter group before installation on the main body. 
     It is clear that a person skilled in the art may make modifications to the blow-by gas filtration assembly so as to satisfy contingent requirements, all contained within the scope of protection as defined by the following claims. 
     LIST OF REFERENCE NUMBERS 
     
         
           1  blow-by gas filtration assembly 
           2  main body 
           20  filtration chamber 
           21  inlet mouth 
           22  outlet mouth 
           220  outlet edge 
           25  insertion opening 
           250  insertion edge 
           3  filter group 
           30  filter medium 
           31 ,  32  filter plate 
           310 ,  320  through openings 
           315  first gasket 
           325  second gasket 
           33  central structure 
           308  first notch 
           309  retaining protrusion elements 
           300  central chamber 
           4  engine group 
           40  engine body 
           41  rotor 
           418  second notch 
           42  stator 
           420  rotor chamber 
           5  shaft 
           51  engine portion 
           518  second protrusion 
           52  filter portion 
           520  outlet duct 
           528  first protrusion 
           529  safety housings 
           521  longitudinal slots 
           522  duct outlet 
           525  inner diffuser 
           6  first bearing 
           7  second bearing 
         X-X rotation axis