WO2023012567A1

WO2023012567A1 - Blow-by gas filtration assembly comprising a turbine

Info

Publication number: WO2023012567A1
Application number: PCT/IB2022/056784
Authority: WO
Inventors: Giorgio Girondi
Original assignee: Ufi Innovation Center S.R.L.
Priority date: 2021-08-06
Filing date: 2022-07-22
Publication date: 2023-02-09
Also published as: IT202100021443A1

Abstract

The invention relates to a blow-by gas filtration assembly (1) which is fluidly connectable to a ventilation circuit for filtering the blow-by gases of an endothermic engine. The filtration assembly (1) has an axis (X-X), comprising: a main body (5) comprising a body wall (51) and an outlet mouth (53); - a radially crossable filter unit (2); - a control unit (3), comprising a turbine (34) which is operable by an oil flow; - a shaft (4) which extends axially, comprising a filter portion (42), connected to the filter unit (2), a control portion (44), connected to the turbine (34), an outflow portion (43) between the filter portion (42) and the control portion (44), an air duct (41) in which the filtered blow-by gases axially flow between an inlet window (412) and an outflow window (413); - an internal structure (6) sealingly engaging the body wall (51), defining a filtration chamber (520) housing the filter unit (2), a control chamber (540) housing the turbine (34), and an outflow chamber (530) fluidly connecting the at least one outflow window (413) and the outlet mouth (53).

Description

"BLOW-BY GAS FILTRATION ASSEMBLY COMPRISING A TURBINE"

DESCRIPTION

Field of application

[0001] The present invention relates to a blow-by gas filtration assembly .

[0002] In particular, the blow-by gas fi ltration assembly according to the present invention is fluidly connectable to a ventilation circuit of the crankcase of an internal combustion engine of a vehicle to receive blow-by gases ( from said crankcase ) and filter them from the suspended particles contained therein .

[0003] Speci fically, "blow-by gases" means the oil vapors vented from the crankcase of an internal combustion engine during its operation . In particular, said blowby gases have a composition similar to that of exhaust gases and are generated by the combustion of the air/ fuel mixture in the combustion chamber . Instead of reaching the exhaust emission circuit , these gases leak into the lower portion of the crankcase , passing by the s ide of the cylinders and carrying carbon particles and oil droplets therewith . In the present discussion, for simplicity, the blow-by gases are considered to consist of air and suspended particles ; said suspended particles include oil droplets and/or carbonaceous particulates .

Background art [0004] In the prior art , filtration assembly solutions which are fluidly connectible to the crankcase and adapted to vent the blow-by gases therefrom are known . [0005] Speci fically, solutions of blow-by gas filtration assemblies are known, which separate said undesired suspended particles from the blow-by gases comprising a filter unit having said purpose .

[0006] In the prior art , a plurality of embodiments of filter assemblies are known, comprising a filter unit comprising a filtering medium of the porous type rotationally moved by a speci fic control drive , so that the suspended particles are separated from the air both when crossing the porous material and by the action of the centri fugal force .

[0007] In particular, solutions are known in which the control drive comprises a turbine rotationally moved by a pressuri zed oil j et .

[0008] Such embodiments typically have a complex shape especially in the fluid connection modes between the filter unit and the ventilation circuit of the crankcase and in the connection modes of the control drive with the filter unit .

[0009] In known solutions , this causes particular problems to blow-by gas filtration assemblies pertaining to the prior art , which have large dimensions , forced fluid connection positions with the engine crankcase , and a complex fluid layout therein .

Solution of the invention

[0010] In the aforesaid prior art , the need to have a blowby gas filtration assembly which solves such problems is thus strongly felt .

[0011] It is the obj ect of the present invention to provide a new embodiment of blow-by gas fi ltration assembly with an innovative geometry and fluid arrangement of the various components included therein .

[0012] Such an obj ect is achieved by the blow-by gas filtration assembly claimed in claim 1 . The claims dependent thereon show preferred variants implying further advantageous aspects .

Description of the drawings

[0013] Further features and advantages of the invention will become apparent from the description provided below of preferred exemplary embodiments thereof , given by way of non-limiting example , with reference to the accompanying drawings , in which :

[0014] - Figure 1 shows an axonometric view with separate parts of the blow-by gas filtration assembly in accordance with the present invention, according to a first preferred embodiment ;

[0015] - Figure 2 shows an axonometric view of the blow- by gas fi ltration assembly in an assembled configuration in accordance with the present invention, according to a preferred embodiment ;

[0016] - Figure 3 shows a sectional view along the crosssection plane A-A of the blow-by gas filtration assembly in Figure 2 ;

[0017] - Figure 3a depicts an enlarged detail , indicated by letter K, of a part of the filtration assembly in Figure 3 ;

[0018] - Figure 3b shows a sectional view along the cross section plane B-B of the filtration assembly in Figure 3 ;

[0019] - Figure 4 shows a top view o f the filtration assembly, in accordance with the present invention, in which some parts are shown in a sectional view, according to a second preferred embodiment ;

[0020] - Figure 5 shows a sectional view with separate parts along the plane C-C of the filtration assembly in Figure 4 ;

[0021] - Figure 6 shows a side view of the filtration assembly in Figure 4 , in an assembled conf iguration;

[0022] - Figure 6a shows a sectional view along the plane D-D of the filtration assembly in Figure 6 ;

[0023] - Figure 6b shows a sectional view along the plane E-E of the filtration assembly in Figure 6 ; [0024] - Figure 7 depicts a side view of the filtration assembly in Figure 6 ;

[0025] - Figure 7a shows a sectional view along the plane F-F of the filtration assembly in Figure 7 .

Detailed description

[0026] In the accompanying drawings , reference numeral 1 indicates as a whole a blow-by gas filtration assembly adapted to perform the f iltration/ separation action on the ( liquid and/or solid) particles suspended in the gas stream .

[0027] Said blow-by gas filtration assembly 1 is fluidly connectable to a ventilation circuit of the crankcase of an internal combustion engine to receive blow-by gases and filter them from the suspended particles contained therein and return the clean ( i . e . filtered) gas stream to other systems of the vehicle , such as for example to the engine air intake circuit communicating with the combustion chamber of the endothermic engine .

[0028] Preferably, said blow-by gas filtration assembly 1 is directly mountable to the crankcase of an internal combustion engine of a vehicle by a speci fic fixing flange .

[0029] 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 . [0030] According to a preferred embodiment , the X-X axis extends substantially in a vertical direction with respect to a ground floor . In other words , according to a preferred embodiment , the filtration assembly 1 is housable in a vehicle so as to position the X-X axis substantially vertically .

[0031] According to the present invention, the blow-by gas filtration assembly 1 comprises a main body 5 which comprises a housing 500 .

[0032] Said main body 5 further comprises a body wall 51 , having for example an annular shape with respect to the X-X axis which delimits said housing 500 therein .

[0033] As widely described below, the control action of the filtration assembly 1 and the filtration action of the blow-by gases take place inside said housing 500 . In other words , the components adapted to perform such actions are positioned in said main body 5 , preferably in the housing 500 , as shown by way of example in the figures attached below .

[0034] According to the present invention, the blow-by gas filtration assembly 1 comprises an internal structure 6 which sealingly engages the body wall 51 .

[0035] Said internal structure 6 divides the housing 500 into a filtration chamber 520 , into which the blow-by gases to be filtered flow, a control chamber 540 , into which pressuri zed oil is supplied for the operation of the turbine 34 , and an outflow chamber 530 , into which the filtered blow-by gases flow .

[0036] According to the present invention, the outflow chamber 530 is positioned to be axially included and sealingly separated between said filtration chamber 520 and said control chamber 540 .

[0037] In other words , the outflow chamber 530 is sealingly separated from the filtration chamber 520 and the control chamber 540 , so that the filtered blow-by gases present in said outflow chamber 530 can flow out from the filtration assembly circulating through a speci fic predetermined path .

[0038] According to the present invention, the blow-by gas f iltration/ separation operations take place in the filtration chamber 520 . The filtration chamber 520 is thus fluidly connected to the ventilation circuit o f the crankcase of an internal combustion engine of a vehicle to receive the fouled blow-by gases , i . e . comprising suspended ( solid and/or liquid) particles , and reintroduce clean blow-by gases , i . e . cleaned of suspended particles , into the engine air intake system . [0039] According to the present invention, the main body 5 comprises respective inlets and outlets for the blowby gases . [0040] In particular, the main body 5 comprises an inlet mouth 52 which is fluidly connectable to the ventilation circuit of the engine crankcase of a vehicle for receiving the blow-by gases to be filtered .

[0041] Preferably, said inlet mouth is formed on the body wall 51 of the main body 5 . Preferably, said inlet mouth 52 is formed on the body wall 51 o f the main body 5 which delimits the fi ltration chamber 520 . In a preferred embodiment , said inlet mouth 52 is formed radially spaced apart from the X-X axis , for example positioned tangentially to the body wall 51 . In a further preferred embodiment , said inlet mouth 52 is substantially parallel to the X-X axis .

[0042] Furthermore , the main body 5 pre ferably comprises an outlet mouth 53 which is connectable to the engine air suction system of a vehicle to enable the outflow of the blow-by gases filtered by the filtration assembly 1 . [0043] Preferably, said outlet mouth 53 is formed radially spaced apart from the X-X axis , for example substantially perpendicular to the X-X axis .

[0044] According to a preferred embodiment , the outlet mouth 53 and the inlet mouth 52 are positioned on the body wall 51 mutually parallel to each other .

[0045] According to a preferred embodiment , the main body 5 comprises a first hal f-body 54 and a second hal f-body 55 which are mutually sealingly engageable along the X-

X axis , so as to delimit the housing 500 .

[0046] Speci fically, in a preferred embodiment , the filtration chamber 520 is defined, at least partially, by the second hal f-body 55 . Preferably, the filtration chamber 520 is axially delimited, for example at the bottom, by the internal structure 6 .

[0047] Additionally, in a preferred embodiment , the control chamber 540 is defined, at least partially, by the first hal f-body 54 . Preferably, the control chamber 540 is axially delimited, for example at the top, by the internal structure 6 .

[0048] According to the present invention, the blow-by gas filtration assembly 1 comprises a filter unit 2 speci fically adapted to perform said operations of f iltering/ separating the particles suspended in the blow-by gases .

[0049] Said filter unit 2 is positioned and operating in the filtration chamber 520 .

[0050] The filter unit 2 extends along the X-X axis having a hollow tubular shape , for example cylindrical , comprising a central cavity 200 .

[0051] The filter unit 2 is radially cros sable by the blowby gases from the outside towards the inside .

[0052] Preferably, the inlet mouth 52 faces the filter unit 2 .

[0053] According to a first preferred embodiment , the inlet mouth 52 radially faces the outer surface of the filter unit 2 .

[0054] According to a second preferred embodiment , the inlet mouth 52 axially faces the filter unit 2 , for example faces a filter plate of the filter unit 2 , described below .

[0055] According to a preferred embodiment , the filter unit 2 comprises a filtering medium 25 . The filtering medium 25 which is radially crossable from the outside towards the inside , comprises a non-woven fabric pleated in a star shape or a cylindrical porous partition .

[0056] Preferably, the central cavity 200 is radially surrounded by the filtering medium 25 .

[0057] In other words , the filter unit 2 identi fies , in the filtration chamber 520 , a dirty side in which there are blow-by gases to be filtered and a clean side in which there are filtered blow-by gases . The inlet mouth 52 is fluidly connected to said dirty side , whereas the outlet mouth 53 is fluidly connected to said clean side . [0058] According to the present invention, the outflow chamber 530 is sealingly separated from the filtration chamber 520 . According to the present invention, the outflow chamber 530 is sealingly separated from the dirty side of the filtration chamber 520 .

[0059] According to the present invention, the outflow chamber 530 is in fluid communication with the clean side of the filter unit 2 , in particular with the central cavity 200 delimited by the filtering medium 25 .

[0060] According to the present invention, the blow-by gas filtration assembly 1 comprises a control unit 3 operatively connected to the filter unit 2 to rotationally control it about the X-X axis .

[0061] The control unit 3 comprises a turbine 34 which is rotationally operable about the X-X axis by an oil flow .

[0062] Preferably, said turbine 34 is housed in the control chamber 540 .

[0063] In one embodiment , the control unit 3 comprises an oil noz zle 35 , open into the control chamber 540 , speci fically adapted to dispense a pressuri zed oil j et towards the turbine 34 , preferably acting in the tangential direction thereto .

[0064] Preferably, said oil noz zle 35 is fluidly connected to a fluid circuit in which engine oi l flows .

[0065] According to a preferred embodiment , the oil noz zle 35 is made passing through a side wall of the main body 5 , in particular of the first hal f-body 54 .

[0066] Preferably, the oil noz zle 35 fluidly communicates with an oil supply channel passing through a fixing flange at the engine crankcase provided on the first hal f-body 54 .

[0067] Preferably, the first hal f-body 54 is further speci fically shaped to collect the oil dispensed by the oil noz zle 35 for reintroducing it into the engine oil fluid circuit from where it comes , for example for directing it towards the engine sump, or into a di f ferent fluid circuit for engine oil .

[0068] According to the present invention, the blow-by gas filtration assembly 1 comprises a shaft 4 which extends along the X-X axis , speci fically adapted to be operatively connected to the filter unit 2 and the control unit 3 .

[0069] According to the present invention, the shaft 4 axially crosses , and is rotationally freely engaged with, the internal structure 6 , as described below .

[0070] According to a preferred embodiment , the shaft 4 mainly extends into the second hal f-body 55 and partially into the first hal f-body 54 .

[0071] Preferably, the shaft 4 is hollow in at least one portion thereof .

[0072] According to a preferred embodiment , the shaft 4 is made as a single component .

[0073] According to one embodiment , the shaft 4 is a hollow body consisting of two or more parts which are mechanically connectable to one another ( for example by welding, mechanical couplings , screws , or the like ) reversibly or irreversibly in order to form a s ingle component the parts of which rotate synchronously upon operation command by the control unit 3 .

[0074] According to the present invention, the shaft 4 comprises a filter portion 42 , to which the filter unit 2 is integrally rotationally connected, and a control portion 44 , to which the turbine 34 is integrally rotationally connected .

[0075] In particular, in the present description, " integrally" means that the control unit 3 and the f ilter unit 2 are mechanically connected to the shaft 4 for rotating in unison ( or synchronously) .

[0076] The modes of engaging the control unit 3 with the shaft 4 , and in particular the turbine 34 , are not limiting for the purposes of the present invention .

[0077] In a preferred embodiment , the turbine 34 i s integrally rotationally connected to the control portion 44 by a threaded coupling 345 .

[0078] The modes of engaging the filter unit 2 with the shaft 4 are not limiting for the purposes of the present invention, with the exception of the features described below .

[0079] According to a preferred embodiment , the shaft 4 and the filter unit 2 are mutually engageable with each other by screwing, through threaded portions speci fically provided .

[0080] According to a preferred embodiment , the shaft 4 comprises a preferably external shaft thread 49 , for example positioned axially in the filter portion 42 . Furthermore , the filter unit 2 preferably comprises a preferably internal filter thread 29 , for example positioned on a filter plate of the filter unit 2 , which will be described below .

[0081] According to one embodiment , the shaft 4 and the filter unit 2 are mutually engageable with each other by shape coupling .

[0082] According to other embodiments , the shaft 4 and the filter unit 2 are mutually engageable being speci fically shaped and providing for the insertion of speci fic insert-type or threaded components .

[0083] According to the present invention, the shaft 4 comprises an outflow portion 43 , axially included between the filter portion 42 and the control portion 44 , which is fluidly connectable to the outflow chamber 530 .

[0084] Speci fically, the shaft 4 comprises an air duct 41 which extends along the X-X axis , through which the filtered blow-by gases flow . [0085] The air duct 41 extends between an inlet window 412 , positioned in the filter portion 42 , and an outflow window 413 , positioned in the outflow portion 43 .

[0086] According to a preferred embodiment , the shaft 4 comprises an air duct 41 which extends along the X-X axis and which comprises an inlet window 412 which is fluidly connectable to the central cavity 200 of the filter unit 2 .

[0087] In a preferred embodiment , the shaft 4 comprises a plurality of inlet windows 412 , preferably angularly distributed .

[0088] Preferably, the shaft 4 comprises a plurality of outflow windows 413 , preferably angularly distributed .

[0089] Preferably, the outflow chamber 530 is sealingly separated from the filtration chamber 520 , in particular the outflow chamber 530 is sealingly separated from the dirty side of the filtration chamber 520 , and is fluidly connected to the clean side of the filtration chamber 520 through the air duct 41 . Preferably, said outflow chamber 530 is fluidly connected to the clean side of the filtration chamber 520 by at least one outflow window 413 .

[0090] According to the present invention, the shaft 4 receives the blow-by gases filtered by the filter unit 2 in the axial section corresponding to the filter portion 42 , through the at least one inlet window 412 , preferably in the radial direction, and yields the blowby gases in a distinct axial section, corresponding to the outflow portion 53 , through the at least one outflow window 413 , preferably in the radial direction .

[0091] In other words , said air duct 41 extends into the filter portion 42 and the outflow portion 43 , so as to be fluidly connected on one side to the central cavity 200 and on the other side to the outf low chamber 530 .

[0092] Preferably, the air duct 41 is housed and fluidly connected to the filter unit 2 in the clean side of the filtration chamber 520 .

[0093] This means that , according to the present invention, the outflow portion 43 is positioned in the outflow chamber 530 , so that said outflow window 413 is fluidly connected to the outlet mouth 53 of the main body .

[0094] In other words , the filtered blow-by gases flow into the air duct 41 , cross the outflow window 413 , and flow through the outflow chamber 530 towards the outlet mouth 53 .

[0095] According to a preferred embodiment , at the axial ends of the shaft 4 there are provided no openings through which the filtered gases flow . Preferably, one end of the shaft 4 is closed in one piece , whereas the other axial end of the shaft 4 is closed by another component of the assembly, such as , for example , by the filter unit 2 itsel f , for example by a filter plate of the filter unit 2 described below .

[0096] According to a preferred embodiment , the internal structure 6 is a distinct components from the main body 5 , preferably made in one piece , preferably having an annular shape .

[0097] According to a preferred embodiment , the internal structure 6 is made as a single component .

[0098] According to an alternative embodiment , the internal structure 6 consists of two or more parts which are mechanically connectable to one another ( for example by welding, mechanical couplings , screws , or the like ) reversibly or irreversibly in order to form a s ingle component the constituent parts of which participate in delimiting the outflow chamber 530 and supporting the support and centering unit 7 adapted to rotationally support the shaft 4 .

[0099] According to a preferred embodiment , the internal structure 6 comprises a head wall 62 and a bottom wall 63 which extend substantially in a radial direction with respect to the X-X axis , being axially spaced apart and delimiting the outflow chamber 530 therebetween .

[00100] Preferably, the head wall 62 and the bottom wall 63 each comprise a respective sealing portion 621 , 631 which is radially distal from the X-X axis , sealingly engaging the body wall 51 .

[00101] According to a preferred embodiment , a respective gasket element is housed in each sealing portion 621 , 631 .

[00102] According to a preferred embodiment , each sealing portion 621 , 631 houses a respective radial gasket , for example an 0-ring .

[00103] According to a preferred embodiment , the internal structure 6 is configured as a removable component from the housing 500 of the main body 5 . Preferably, the internal structure 6 is fixable to the main body 5 , for example to the body wall 51 , by a snap coupling .

[00104] According to a preferred embodiment , the internal structure 6 is configured as a non-removable component fixed to the main body 5 , for example fixed by welding to the first hal f-body 54 or to the second hal fbody 55 .

[00105] According to one embodiment , the internal structure 6 comprises support portions adapted to interact with the body wall 51 , or in general with the main body 5 , to support said internal structure 6 in the axial direction . [00106] Preferably, said support portions may be formed on the bottom wall 63 and/or the head wall 62 .

[00107] According to a preferred embodiment , the bottom wall 63 comprises a support portion 635 which proj ects radially externally beyond the sealing portion 631 of the bottom wall 63 .

[00108] Preferably, furthermore , with the first halfbody 54 and the second hal f-body 55 mutually engaged, said support portion 635 is configured to be at least partially axially interposed between said first hal fbody 54 and said second hal f-body 55 . Advantageously, said support portion enables the internal structure 6 to be axially supported on the first hal f-body 54 .

[00109] According to a preferred embodiment , the internal structure 6 comprises support portions adapted to interact with the body wall 51 , or in general with the main body 5, in order to provide a rotational abutment and lock the angular position of the internal structure 6 inside the housing 500 .

[00110] According to a preferred embodiment , the outflow chamber 530 is shaped so as to promote the outflow of the blow-by gases . Preferably, for example , the outflow chamber 530 is radially externally larger . In fact , the head wall 62 preferably extends in the radial direction in an inclined manner over a distal section from the X-X axis , i . e . it has an at least partially conical shape .

[00111] Preferably, such a distal section from the speci fically inclined X-X axis further enables the correct outflow of the oil recovered in the filtration chamber 520 .

[00112] According to a preferred embodiment , the internal structure 6 comprises an annular outflow wall 64 , positioned in a radially proximal region to the X-X axis .

[00113] According to a preferred embodiment , the annular outflow wall 64 extends in the axial direction about the X-X axis between the head wall 62 and the bottom wall 63 .

[00114] According to a preferred embodiment , the annular outflow wall 64 extends parallel to the X-X axis between the head wall 62 and the bottom wall 63 .

[00115] According to a preferred embodiment , the outflow chamber 530 extends at least partially radially about the X-X axis , for example it has an annular shape, being axially between the head wall 62 and the bottom wall 63 , and being radially between the body wall 51 and the annular outflow wall 64 .

[00116] According to a preferred embodiment , the outflow chamber 530 is housed at least partially, preferably entirely, in the main body 5 .

[00117] According to a preferred embodiment , the outflow chamber 530 is housed at least partially, preferably entirely, in the internal structure 6 .

[00118] According to a preferred embodiment , the internal structure 6 comprises at least one structure mouth 65 , preferably a plurality of structure mouths 65 , radially passing into the annular outflow wall 64 , adapted to fluidly connect the at least one outflow window 413 to the outflow chamber 530 .

[00119] In other words , the blow-by gases output from the outflow window 413 cross said at least one structure mouth 65 to flow into the out flow chamber 530 towards the outlet mouth 53 .

[00120] According to a preferred embodiment , the at least one structure mouth 65 is at least partially radially aligned with the outflow window 413 .

[00121] According to a preferred embodiment , in which the blow-by gas filtration assembly 1 is mountable to the engine crankcase in a substantially vertical position with respect to a ground floor, the internal structure 6 further comprises at least one oil recovery hole 66 , preferably a plurality of oil recovery holes 66 , for example being angularly equidistant , which fluidly connects the filtration chamber 520 to the control chamber 540 .

[00122] In other words , in such a preferred embodiment , the particles of oil blocked and/or agglomerated by the filter unit 2 and present in the dirty side of the filtration chamber 520 , flow downwards , for example due to the force of gravity, along a side wall of the main body 5 , for example of the second hal fbody 55 , and flow through said at least one oil recovery hole 66 , thus reaching the control chamber 540 .

[00123] In other words , in a preferred embodiment , the at least one oil recovery hole 66 axially passes between the head wall 62 and the bottom wall 63 .

[00124] According to one embodiment , the at least one oil recovery hole 66 axially passes into the annular outflow wall 64 .

[00125] In other words , the at least one oil recovery hole 66 is fluidly separated from the outflow chamber 530 .

[00126] In one embodiment , the at least one oil recovery hole is made in a side wall of the main body 5 , for example in the body wall 51 externally radially delimiting the outflow chamber 530 .

[00127] According to a preferred embodiment , the blowby gas filtration assembly 1 comprises a support and centering unit 7 which engages the shaft 4 for rotationally supporting it about the X-X axis .

[00128] According to a preferred embodiment , the blowby gas filtration assembly 1 comprises a support and centering unit 7 which engages the shaft 4 for keeping it centered to the X-X axis and is adapted to promote the rotation thereof .

[00129] Speci fically, said support and centering unit 7 is housed on the internal structure 6 .

[00130] According to a preferred embodiment , the support and centering unit 7 comprises a first bearing 71 positioned in a proximal region to the filter unit 2 . [00131] According to a preferred embodiment , the support and centering unit comprises a first bearing 71 positioned in a first bearing seat 641 , preferably axially facing the filtration chamber 520 .

[00132] According to a preferred embodiment , said first bearing seat 641 is integrally formed with the internal structure 6 .

[00133] Preferably, said first bearing 71 is of the fluid seal type .

[00134] According to a preferred embodiment , the first bearing 71 fluidly separates the filtration chamber 520 from the outflow chamber 530 . Preferably, the first bearing 71 sealingly separates the dirty side o f the filtration chamber 520 from the outflow chamber 530 . [00135] Furthermore , according to a preferred embodiment , the filter unit 2 comprises a first filter plate 21 and a second filter plate 22 , preferably having a substantially planar shape and mutually arranged at the axial ends of the filtering medium 25.

[00136] Furthermore , according to a preferred embodiment , the filter unit 2 comprises an external filter structure 24 which externally surrounds the filtering medium 25 and j oins the two filter plates 21 , 22 . Preferably, said external filter structure 24 has a plurality of through openings adapted to allow the passage of fluid under filtration .

[00137] According to a preferred embodiment , said external filter structure is formed in a single piece with the second filter plate or the f irst filter plate . [00138] As shown by way of example in the accompanying drawings , the central cavity 200 extends through the first filter plate 21 , surrounded by the filtering medium 25 .

[00139] According to first embodiment , the filter unit 2 sealingly engages the shaft 4 in a sealing region provided on the filter portion 42 .

[00140] According to first embodiment , the filter unit 2 sealingly engages the shaft 4 in two axially distinct sealing regions , both provided on the filter portion 42 . [00141] Preferably, said two sealing regions are located close to the first filter plate 21 and the second filter plate 22 . Preferably, at said sealing regions , the filter unit 2 and the shaft 4 are mutually speci fically shaped to sealingly engage each other and/or the filter unit mounts speci fically shaped gasket elements .

[00142] According to a preferred embodiment , the first filter plate 21 of the filter unit 2 comprises an annular portion 215 positioned axially abutting against the inner slewing ring of the first bearing 71 . According to a preferred embodiment , the first filter plate 21 of the filter unit 2 comprises an annular portion 215 positioned axially abutting against the inner slewing ring of the first bearing 71 to reali ze a separation region between the dirty side and the clean side of the filter group 2 . [00143] According to a preferred embodiment , the first filter plate 21 comprises a first annular portion 215 which axially extends , positioned axially abutting against the first bearing 71 , in particular with the inner slewing ring of the first bearing 71 .

[00144] According to a preferred embodiment , the first filter plate 21 comprises a first annular portion 215 which axially extends , positioned axially abutting against the first bearing 71 , in particular with the inner slewing ring of the first bearing 71 which rotationally engages the shaft 4 .

[00145] According to a preferred embodiment , the first filter plate 21 comprises a first annular portion 215 which axially extends , positioned axially abutting against the first bearing 71 , in particular with the inner slewing ring of the first bearing 71 which rotationally engages the shaft 4 between the f ilter portion 42 and the outflow portion 43 .

[00146] According to a preferred embodiment , the filter thread 29 is positioned on said first annular portion 215 , pre ferably on an inner surface facing the central cavity 200 .

[00147] According to a preferred embodiment , the filter thread 29 and the shaft thread 49 are mutually engageable when screwed together, so that the filter unit 2 screwed onto the shaft 4 axially engages the first bearing 71 , preferably the inner slewing ring o f the first bearing 71 .

[00148] Preferably, said mutual axial engagement between the filter unit 2 and the first bearing 71 avoids any further screwing of the filter unit 2 . Preferably, the axial reciprocal engagement between first annular portion 215 of the first filter plate 21 comprised in the filter group 2 and the first bearing 71 prevents a further screwing of the filter group 2 . Preferably, the threaded coupling between the shaft thread 49 and the filter thread 29 can reali ze a hermetically sealing .

[00149] According to a preferred embodiment , the second filter plate 22 comprises a second annular portion 225 which axially extends , radially defining a shaft centering seat 226 , in which an axial end 47 of the shaft 4 opposite to the control portion 44 is housed to be rotationally free .

[00150] According to a preferred embodiment , the axial end 47 of the shaft 4 is free from constraints , i . e . is positioned in a cantilever fashion in the central chamber 200 of the filter unit 2 .

[00151] In other words , in a preferred embodiment , the axial end 47 is free from components adapted to support and promote the rotation thereof .

[00152] In other words , the shaft 4 is rotationally supported by the support and centering unit 7 installed on the internal structure 6 and which engages the shaft in axially distal regions from said axial end 47 .

[00153] In other words , the shaft 4 is rotationally supported by the support and centering unit 7 housed on the internal structure 6 and positioned at the axial ends of the outflow portion 43 . In other words , the outflow portion 43 is positioned axially between the first bearing 71 and the second bearing 72 .

[00154] According to a preferred embodiment , the shaft 4 is rotationally supported by the support and centering unit 7 housed on the internal structure 6 and positioned at the axial ends of the outflow chamber 530 . In other words , the outflow chamber 530 is positioned axially between the first bearing 71 and the second bearing 72 .

[00155] According to a preferred embodiment , the air duct 41 passes through the axial end 47 , for example it is open and axially faces the central cavity 200 .

[00156] According to a preferred embodiment , the air duct 41 passes through the axial end 47 , for example it is open and axially faces the second filter plate 22 .

[00157] Preferably, the second filter plate 22 comprises at least one auxiliary gasket 227 , preferably a plurality of them, preferably of the dynamic type , mounted at the axial end 47 of the shaft 4 and positioned circumferentially in contact with the second annular portion 225 , adapted to substantially perform a sealing function .

[00158] In other words , the second filter plate 22 hermetically closes the air duct 41 at the axial end 47 of the shaft 4 opposite to the control portion 44 .

[00159] According to a preferred embodiment , the support and centering unit 7 comprises the second bearing 72 positioned in a proximal region to the turbine 34 .

[00160] According to a preferred embodiment , the support and centering unit 7 comprises a second bearing 72 positioned in a second bearing seat 642 , preferably axially facing the control chamber 540 .

[00161] According to a preferred embodiment , said second bearing seat 642 is integrally formed with the internal structure 6 .

[00162] According to a preferred embodiment , the second bearing 72 is of the fluid sealing type .

[00163] According to a preferred embodiment , the second bearing 72 fluidly separates the control chamber 540 from the outflow chamber 530 .

[00164] In a preferred embodiment , the support and centering unit 7 comprises speci fic gaskets , preferably positioned adj acent to the first bearing 71 and the second bearing 72 , respectively, having speci fic fluid sealing functions .

[00165] Furthermore , in a preferred embodiment , the turbine 34 is axially positioned in axial abutment with the second bearing 72 . Preferably, the turbine 34 is in axial abutment with the inner slewing ring of the second bearing 72 .

[00166] According to a preferred embodiment , the turbine 34 comprises a fixing collar 341 in axial abutment with the second bearing 72 , in particular with the inner slewing ring of the second bearing 72 which rotationally engages the shaft 4 .

[00167] According to a preferred embodiment , the turbine 34 comprises a fixing collar 341 in axial abutment with the second bearing 72 , in particular with the inner slewing ring of the second bearing 72 which rotationally engages the shaft 4 between the outflow portion and the control portion 44 .

[00168] According to a preferred embodiment , the internal structure 6 comprises an axial abutment shoulder 69 positioned in a radially proximal region to the turbine 34 .

[00169] According to a preferred embodiment , the internal structure 6 comprises an axial abutment shoulder 69 positioned in a radially proximal region to the second bearing seat 642 in which the second bearing 72 is housed .

[00170] Preferably, furthermore , the support and centering unit 7 comprises an elastic abutment element 75 , positioned axially between the second bearing 72 and the axial abutment shoulder 69 , adapted to be elastically deformed for applying a preload force to both bearings

71 , 72 . [00171] In particular, said preload force is discharged directly onto the second bearing 72 by the elastic abutment element 75 and indirectly on the first bearing 71 due to the rotational coupling obtained with the shaft 4 .

[00172] Advantageously, said preload force enables to keep the position of the bearings stable and to obtain a stable rotation of the shaft , thus minimi zing disturbances and undesired ef fects generated by possible vibrations .

[00173] According to a preferred embodiment , the elastic abutment element 75 is annular in shape and is mounted to the outflow portion 43 .

[00174] According to a preferred embodiment , the elastic abutment element 75 is annular in shape and is mounted between the outflow portion 43 and the control portion 44 .

[00175] In a preferred embodiment , the annular outflow wall 64 defines an auxiliary housing 76 with the shaft 4 , preferably having an annular shape , in which said support and centering unit 7 is housed and operated .

[00176] The present invention is not limited either to the shape or to the type of the first and second bearings . Preferably, the term "bearing" means a plain bearing, a ball bearing, or a bushing . [00177] According to a preferred embodiment , the internal structure 6 further comprises an annular covering wall 67 , which extends from the bottom wall 63 defining a turbine housing 670 , in which the turbine 34 , preferably the fixing collar 341 , is at least partially housed .

[00178] According to a preferred embodiment , the internal structure 6 further comprises an annular covering wall 67 , positioned radially externally spaced apart from the annular outflow wall 64 , defining a housing 670 therewith, in which the turbine 34 , preferably the fixing collar 341 , is at least partially housed .

[00179] According to a preferred embodiment , the shaft 4 comprises a closing wall 45 , adapted to close said air duct 41 to force the outflow of filtered blow-by gases through the at least one outflow window 413 .

[00180] According to a preferred embodiment , the closing wall 45 is positioned at the outflow portion 43 , proximally to the control portion 44 .

[00181] Preferably, said closing wall 45 is shaped to promote the outflow of the blow-by gases towards at least one outflow window 413 .

[00182] According to a preferred embodiment , the shaft 4 is made of a thermoplastic material obtained by a single molding operation.

[00183] Preferably, the shaft 4 is made of polyphenylene sulfide (PPS) .

[00184] Preferably, the shaft 4 is made of a material based on polyphenylene sulfide (PPS) .

[00185] Preferably, the shaft 4 is made of a material based on polyphenylene sulfide (PPS) reinforced with fiberglass (PPS + GF15, PPS + GF30, PPS + GF40) .

[00186] Preferably, the shaft 4 is made of a nylonbased material (PA, PA 6, PA 6.6, or a mixture thereof) . [00187] Preferably, the shaft 4 is made of a nylonbased material reinforced with fiberglass. (PA+GF, PA 6.6+ GF35, PA 6+PA 6.6+GF 35)

[00188] Preferably, the shaft 4 is made of a material which comprises a polyamide-based mix (e.g., PPA) .

[00189] According to one embodiment, the shaft 4 is made of a metal material. Preferably, the shaft 4 is made of an aluminum alloy.

[00190] According to a preferred embodiment, the internal structure 6 is made of one of the above-listed materials for the shaft 4.

[00191] In a preferred embodiment, the main body 5 comprises a transit mouth 59 passing radially into the body wall 51, for example passing through a side wall of the second half-body 55, and facing the outflow chamber 530 , through which the filtered blow-by gases flow towards the outlet mouth 53 .

[00192] According to a preferred embodiment , the main body 5 comprises a cover unit 100 , which is configurable to adj ust the flow of the filtered blow-by gases crossing the transit mouth 59 .

[00193] According to a preferred embodiment , the cover unit 100 comprises a closing cover 110 and a vent valve 120 contained in a valve seat defined in the closing cover 110 . Said vent valve 120 is adapted to adj ust the flow of the blow-by gases flowing out from the filtration ass e mb 1 y 1 .

[00194] Preferably, the outlet mouth 53 is positioned on said closing cover 110 .

[00195] Preferably, the vent valve 120 comprises a membrane element 121 which is elastical ly yieldable i f subj ected to a higher pressure than a certain threshold value .

[00196] Therefore , the vent valve 120 i s preferably adapted to prevent the onset of overpressures in the ventilation circuit of the engine crankcase .

[00197] Preferably, said membrane element 121 comprises an elastically deformable movable portion 125 , adapted to close the transit towards the outlet mouth 53 i f any overpressure arises in the ventilation circuit of the engine crankcase .

[00198] In a preferred embodiment , the vent valve 120 comprises a preload element 123 which acts on the movable portion 125 with a force in the opposite direction to the deformation direction of said movable portion 125 .

[00199] Innovatively, the blow-by gas filtration assembly of the present invention largely ful fills the purpose of the present invention . Innovatively, the blow-by gas filtration assembly has a new and innovative fluid arrangement .

[00200] Advantageously, the fluid management of the flows inside the blow-by gas filtration assembly enables to perform an ef ficient filtration in a highly compact space .

[00201] Advantageously, the blow-by gas filtration assembly has highly compact dimensions .

[00202] Advantageously, the outflow of the filtered blow-by gases follows a substantially radial direction .

[00203] Advantageously, the internal structure is designed to identi fy and fluidly separate the outflow chamber from the filtration chamber ( in particular from the dirty side of the filtration chamber ) and the control chamber, in a simple and ef fective manner .

[00204] Advantageously, the internal structure fluidly separates the filtration chamber from the outflow chamber, ensuring the correct outflow of the blow-by gases from the inlet mouth towards the outlet mouth of the main body, thus minimiz ing the load losses associated with the filtration assembly .

[00205] Advantageously, the main body is speci fically shaped to ensure an optimal operation of the control unit . In fact , advantageously, the main body, and in particular the presence of the oil recovery holes , ensures the correct management of the engine oil dispensed under pressure from the oil noz zle and of the oil filtered from the blow-by gases from the filtration chamber .

[00206] Advantageously, the head wall is speci fically shaped to promote the outflow of the filtered blow-by gases and convey the filtered oil into the dirty region of the filtration chamber towards the oil recovery holes . [00207] Advantageously, the internal structure is a compact component capable of rotationally supporting the shaft and the f ilter unit while creating the fluid coupling of the filter unit to the ventilation circuit of the engine crankcase .

[00208] Advantageously, the internal structure is a compact component capable of rotationally supporting the shaft and the filter unit by means of bearings which are placeable in speci fic seats integrated onto said structure , provided on walls positioned close to each other and on opposite sides of the outflow chamber - thus minimi zing the risk of possible misalignments between the respective seats , reducing the risk of possible undesired vibrations or stresses on the shaft , and thus of fering a reliable filtering module .

[00209] Advantageously, the internal structure is a component which is easily moldable/ forgeable onto which di f ferent components can be integrated according to the needs .

[00210] Advantageously, the seat for positioning the first bearing is provided in an upper geodetic position with respect to the drainage hole provided on the head wall , thus preventing any oil drops collected in the filtration chamber from being able to reach the outflow chamber .

[00211] Advantageously, on the portion which faces the control chamber, the internal structure comprises one or more annular covering walls intended to define the turbine housing seat and form a labyrinth-shaped path useful for preventing any oi l drops dispersed from the pressuri zed j et or the filtration chamber from being able to reach the second bearing or the outflow chamber . [00212] Advantageously, the internal structure is a multi functional component which comprises the bearing housing seats and abutment surfaces required for the operation of elastic loading elements useful for maintaining the working position of the shaft and the bearings themselves .

[00213] Advantageously, the internal structure is a component which extends in the radial direction ensuring, on the one hand, the hermetic coupling to the internal surfaces of the main body, and on the other, the rotational coupling to the filter unit . Advantageously, the internal structure enables to maintain the alignment between the main axis of the assembly and the rotation axis o f the filter unit .

[00214] Advantageously, the internal structure supports most of the components of the assembly, facilitating the insertion thereof into the filtration chamber, for example through a single operation, thus simpli fying the process of mounting the filtration assembly and reducing the production costs thereof .

[00215] It is apparent that , in order to meet contingent needs , those ski lled in the art may make changes to the blow-by gas filtration assembly described above , all of which are contained within the scope of protection as defined in the fol lowing claims .

[00216] List of reference symbols :

1 blow-by gas filtration assembly filter ass emb 1 y first filter plate 5 first annular portion second filter plate 5 second annular portion6 shaft centering seat 7 auxiliary gasket external filter structure filtering medium filter thread 0 central cavity control unit turbine 1 fixing collar 5 threaded coupling oil noz zle shaft air duct 2 inlet window 3 outflow window filter portion outflow portion control portion closing wall axial end shaft thread main body body wall inlet mouth outlet mouth first hal f-body second hal f-body 0 housing 0 filtration chamber 0 outflow chamber 0 control chamber transit mouth internal structure head wall bottom wall 5 support portion 1 , 631 sealing portion annular outflow wall1 first bearing seat 2 second bearing seat structure mouth oil recovery hole annular covering wall0 turbine housing axial abutment shoulder 7 support and centering unit

71 first bearing

72 second bearing

75 elastic abutment element 76 auxiliary housing

100 cover unit

110 closing cover

120 ventilation valve

121 membrane element 123 preload element

125 movable portion

X-X axis

Claims

1. A blow-by gas filtration assembly (1) fluidically connectable to a ventilation circuit of a crankcase of an internal combustion engine to receive blow-by gases and filter them from the suspended particles contained therein, wherein the filtration assembly (1) has an axis (X-X) and comprises:

- a main body (5) comprising a housing (500) , a body wall (51) , an inlet mouth (52) and an outlet mouth (53) ;

- a filter group (2) radially crossable from the outside to the inside by blow-by gases, having a hollow tubular shape along the axis (X-X) and having a central cavity (200) ;

- a command group (3) , operatively connected to the filter group (2) to command and rotate it about the axis (X-X) , comprising a turbine (34) rotationally operable by an oil flow; a shaft (4) that extends along the axis (X-X) , comprising : i) a filter portion (42) , wherein the filter group (2) is integrally connected to said filter portion (42) ; ii) a command portion (44) , wherein the turbine (34) is integrally connected to said command portion (44) ; iii) an outflow portion (43) axially comprised between the filter portion (42) and the command portion (44) ;

42 and iv) an air duct (41) , through which the filtered blowby gases flow, wherein the air duct (41) extends along the axis (X-X) between at least one inlet window (412) positioned in the filter portion (42) and at least one outflow window (413) positioned in the outflow portion (43) ;

- an internal structure (6) , axially crossed by the shaft (4) , sealingly engaging the body wall (51) dividing the housing (500) into a filtration chamber (520) housing the filter group (2) , a command chamber (540) housing the turbine (34) , and an outflow chamber (530) , in fluid communication with the outflow portion (43) , fluidically connecting the at least one outflow window (413) and the outlet mouth (53) , wherein said outflow chamber (530) is sealingly separated from the filtration chamber (520) and the command chamber (540) .

2. Filtration assembly (1) according to claim 1, wherein the internal structure (6) comprises a head wall (62) and a bottom wall (63) which axially delimit the outflow chamber (530) , each comprising a sealing portion (621, 631) radially distal from the axis (X-X) sealingly engaging the body wall (51) .

3. Filtration assembly (1) according to any one of the preceding claims, comprising a support and centering

43 group (7) suitable for rotationally supporting the shaft (4) , wherein the support and centering group (7) is housed on the internal structure (6) .

4. Filtration assembly (1) according to claim 3, wherein the internal structure (6) comprises an annular outflow wall (64) which extends in the axial direction about the axis (X-X) and defines an annular auxiliary housing (76) with the shaft (4) , wherein the support and centering group (7) is housed in said auxiliary housing (76) .

5. Filtration assembly (1) according to claim 3 or 4, wherein the support and centering group (7) comprises a first bearing (71) positioned in a first bearing seat (641) facing the filtration chamber (520) , said first bearing seat (641) being integrally formed with the internal structure (6) .

6. Filtration assembly (1) according to claim 5, wherein the filter group (2) comprises a first filter plate (21) comprising an annular portion (215) positioned axially abutting against the inner slewing ring of the first bearing (71) .

7. Filtration assembly (1) according to any one of the preceding claims, wherein the shaft (4) and the filter group (2) are engaged by means of a threaded coupling (29, 49) .

8. Filtration assembly (1) according to any one of claims

44 3 to 7, wherein the support and centering group (7) comprises a second bearing (72) positioned in a second bearing seat (642) facing the command chamber (540) , said second bearing seat (642) being integrally formed with the internal structure (6) .

9. Filtration assembly (1) according to claim 8, wherein the turbine (34) is positioned axially abutting against the inner slewing ring of the second bearing (72) .

10. Filtration assembly (1) according to any one of claims 8 to 9, wherein the internal structure (6) comprises an axial abutment shoulder (69) positioned in a proximal region to the second bearing seat (642) , wherein the support and centering group (7) comprises an elastic abutment element (75) positioned axially between the second bearing (72) and the axial abutment shoulder (69) .

11. Filtration assembly (1) according to claim 10, wherein the elastic abutment element (75) is annular in shape, and is mounted between the outflow portion (43) and the command portion (44) .

12. Filtration assembly (1) according to any one of the preceding claims, wherein the internal structure (6) comprises at least one structure mouth (65) radially passing into the annular outflow wall (64) , suitable for fluidically connecting the at least one outflow window (413) to the outflow chamber (530) .

13. Filtration assembly (1) according to any one of claims 3 to 12, wherein the internal structure (6) further comprises an annular covering wall (67) suitable for defining a turbine housing (670) , wherein the turbine (34) is at least partially housed in said turbine housing (670) , said annular covering wall (67) being integrally formed with the internal structure (6) .

14. Filtration assembly (1) according to any one of the preceding claims, wherein the turbine (34) is integrally rotationally connected to the command portion (44) by means of a threaded coupling (345) .

15. Filtration assembly (1) according to any one of the preceding claims, wherein the outflow portion (43) comprises a plurality of outflow windows (413) , arranged angularly spaced apart with respect to the axis (X-X) .

16. Filtration assembly (1) according to any one of the preceding claims, wherein the main body (5) comprises a first half-body (54) and a second half-body (55) which are mutually sealingly engageable along the axis (X-X) so as to tightly delimit the housing (500) , wherein the command chamber (540) is housed in the first half-body (54) and the filtration chamber (520) is housed in the second half-body (55) , wherein the internal structure (6) is preferably housed in the second half-body (55) .

17. Filtration assembly (1) according to any one of the preceding claims, wherein the command group (3) comprises an oil nozzle (35) which opens in the command chamber (540) , suitable for dispensing a pressurized oil jet, preferably in the tangential direction to the turbine ( 34 ) .

18. Filtration assembly (1) according to any one of claims 5 to 17, being mountable in a substantially vertical position with respect to a ground floor, wherein the internal structure (6) comprises at least one oil recovery hole (66) , preferably a plurality of oil recovery holes (66) , which fluidically connects the filtration chamber (520) to the command chamber (540) .

47