EP2038520A1

EP2038520A1 - Blow by gas separator device for an internal combustion engine of a motor vehicle

Info

Publication number: EP2038520A1
Application number: EP06808908A
Authority: EP
Inventors: Roberto Defilippi
Original assignee: Dayco Fluid Technologies SpA; Dytech Dynamic Fluid Technologies SpA
Current assignee: SumiRiko Italy SpA
Priority date: 2006-05-09
Filing date: 2006-09-29
Publication date: 2009-03-25
Anticipated expiration: 2026-09-29
Also published as: DE602006019922D1; ITTO20060333A1; WO2007129137A1; EP2038520B1

Abstract

A separator device (1) for blow-by gases in an internal combustion engine of a motor vehicle comprising an inlet (3) , an outlet (4) , an inertial separator (5) interposed between the inlet (3) and the outlet (4), characterised in that it comprises a cartridge filter (6) arranged in series with respect to the inertial separator (5) .

Description

BLOW BY GAS SEPARATOR DEVICE FOR AN INTERNAL COMBUSTION ENGINE OF A MOTOR VEHICLE

TECHNICAL FIELD The present invention relates to a separator assembly for blow-by gases in an internal combustion engine of a motor vehicle. BACKGROUND ART Motor vehicle internal combustion engines generally comprise a crankcase accommodating the crankshaft and containing lubricating oil. During engine operation, an amount of combustion gases leaks from the combustion chamber through the sealing rings between the cylinders and the liner and enters the crankcase. To prevent the pressure within the crankcase from becoming too high, the blow-by gases are directed back to the combustion chamber through a conduit which connects the crankcase to the intake manifold.

However, the blow-by gases directed back to the combustion chamber are enriched with particles of oil atomised in the crankcase and a separator filter is required to prevent the heavy hydrocarbons of the oil from being burnt and consequently generating polluting emission. For the previously described application, impact separators are normally used, which, however, present excessively complex geometries for meeting the high efficiencies required by recent standards. In the same application, it is known the use of porous filters which however must be replaced because during use they are saturated by the particles of oil they capture and therefore require planned maintenance. The use of self-cleaning filters is also known, in which the filter, for example comprising a metallic mesh, is crossed by a gas flow and simultaneously turning about an axis. The oil particles retained by the filter are ejected by the centrifugal acceleration and the filter is kept clean. However, self-cleaning filters must be connected to a drive and present relatively moving parts which are subjected to wear.

DISCLOSURE OF INVENTION

It is the object of the present invention to construct a separator device having an improved efficiency and a simple structure to be constructed.

The object of the present invention is achieved by a separator device as defined in claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the present invention, a preferred embodiment will now be described only by way of non-limitative example, and with reference to the accompanying drawing, in which:

- figure 1 is a schematic longitudinal section of a separator device according to the present invention; figure 2 is a schematic section of a second embodiment of the separator device of the present invention;

- figure 3 is a top view of the separator device in figure 2; - figure 4 is a section taken along line IV-IV in figure 4; and

- figure 5 is a prospective view of two components of the separator device in figure 2.

BEST MODE FOR CARRYING OUT THE INVENTION In figure 1, number 1 indicates a separator device comprising a casing 2, an inertial separator 5 accommodated within casing 2 and a porous filter 6 arranged within casing 2 downstream of inertial separator assembly 5. The inertial separators exploit the general principle of subjecting a gas flow to accelerations due to changes of direction. Such accelerations applied to the mass of oil particles generate inertial forces which deviate the particles with respect to the path followed by the gas flow and lead them to adhere to the appropriately arranged walls of the separator. Later, the particles enlarge by coalescence and precipitate by gravity. Examples of inertial separators are impact separators and cyclone separators in which centrifugal acceleration is particularly exploited.

Casing 2 of separator device 1 defines an inlet conduit 3 adapted to be connected to the crankcase of an internal combustion engine and arranged upstream of inertial separator 5, an intake manifold 4 adapted to be connected to an intake manifold of the internal combustion engine and arranged downstream of porous filter 6, and an exhaust conduit 7 adapted to be connected to the engine oil sump.

In particular, according to a preferred embodiment, inertial separator 5 comprises a plurality of separator sub-modules 5a reciprocally connected in series and also porous filter 6 comprises a plurality of cartridge sub- modules 6a, for example of the honey comb type, reciprocally connected in series.

According to a embodiment, each separator sub-module 5a is connected to a cartridge sub-module 6a by means of a frame structure to define an integrated module 8.

The frame structure of each integrated module 8 comprises in a single part of polymeric material constructed by moulding three cylindrical walls 9, 10, 11 rigidly connected together to be concentric with an axis A and at least one flow deviation wall 12 exiting from cylindrical wall 9 radially external on opposite side with respect to the two walls 10, 11.

In use, deviation wall 12 has the function of imposing changes of direction to the gas flow and presents any geometry adapted for this purpose. Preferably, deviation wall 12 presents a helical pattern wound about axis A to define a cyclone effect.

On the radial part opposite to deviation wall 12, radially internal cylindrical wall 11 defines a central conduit 16 connected directly to intake manifold 4, and cylindrical wall 10, interposed between wall 9 and wall 11, defines with the former an annular conduit 17 for the passage of gases and with the latter a seat 18 for respective cartridge sub-module βa. In the embodiment shown in figure 1, separator filter 1 comprises three integrated modules 8 coaxially superimposed to axis A and rigidly connected to the latter. The three integrated modules 8 are axially interposed between inlet conduit 3 and exhaust conduit 7 and respective cylindrical walls 9 are fluid-tightly connected one to the other as cylindrical walls 10, 11, so that conduits 16 and 17 are respectively connected in series.

Casing 2 also comprises a callot portion 19, arranged underneath integrated modules 8 and defining exhaust conduit 7. Callot portion 19 comprises a concave wall 20 defining a sump 21 for collecting the oil from integrated modules 8 and a cylindrical supporting wall 22 exiting coaxially with respect to axis A from concave wall 20 to axially support integrated modules 8.

In particular, supporting wall 22 presents the same diameter as cylindrical wall 10 and defines a plurality of radial openings 23 adjacent to callot portion 19 for putting into fluid communication a peripheral chamber 21a of sump 21 arranged underneath deviation walls 12 and annular conduits 17, and a central chamber 21b arranged underneath cartridge sub-modules 6a and central conduit 16.

Furthermore, supporting wall 22 comprises a circumferentially continuous portion 28 which delimits openings 23 parallel to axis A towards intake conduit 3 and is fluid-tightly connected to cylindrical wall 10 of adjacent integrated module 8.

On the axially opposite side with respect to callot portion 19, intake conduit 4 presents an intermediate portion fluid-tightly inserted in a hole defined by casing 2 and an end portion fluid-tightly connected to central conduit 16 of adjacent integrated module 8. Furthermore, separator device 1 comprises a lid 24 within casing 2 to guide the output gases from annular conduit 17 towards the cartridge sub-modules 6a.

In particular, lid 24 comprises a flat wall 25 defining a central hole and a cylindrical side wall 26 exiting from flat wall 25 and having the same diameter as cylindrical walls 9. Lid 24 is fluid-tightly connected to intake manifold 4 on the edge of the central hole and to module 8 axially opposite to callot portion 19 on cylindrical wall 9 to prevent the intake gas from bypassing inertial separator 5.

The operation of separator device 1 is as follows.

The combusted gases rich in oil particles enter casing 2 and are directed towards inertial separator 5.

The helical profile of deviation walls 12 impresses a rotary motion to the gas and the centrifugal acceleration pushes the oil particles, heavier than the gases, to adhere against the wall of casing 2. The particles then tend to enlarge by coalescence and to be directed by gravity towards sump 21 by means of appropriate passages constructed between adjacent deviation- walls 12. The passages are preferably constructed in proximity to cylindrical wall 9. When the gases reach sump 21, supporting wall 22 guides a 180° inversion within annular conduit 17 at peripheral chamber 21a.

Having reached lid 24, flat wall 25 guides a second inversion of the gases within cartridge sub-assemblies 6a. Having reached sump 21 again at central chamber 21b, the gases are inverted a third time within central conduit 16 and exit towards the manifold through intake conduit 4.

In use, supporting wall 22 and openings 23 must be appropriately dimensioned to prevent the exhaust gases from bypassing annular conduit 17 and cartridge sub- modules 6a. For this purpose, the oil head present in sump 21 must be higher than openings 23 and lap the circumferentially continuous portion 28 of supporting wall 22. In this way, openings 23 are closed to the passage of incoming gas from inertial separator 5 and peripheral 21a and central 21b chambers are fluidically connected only by means of annular conduits 17 and cartridge sub- modules 6a. However, the oil head must not reach sub- module βa of integrated module 8 next to callot portion 19. Indeed, the passages between inertial separator 5 and annular conduit 17 and between cartridge sub-module 6a and central conduit 16 must always be free to allow the passage of gases and to prevent cartridge sub-module 6 from being contaminated by the oil present in central chamber 21b.

Figure 2 shows a separator device 30 in which equal or functionally identical elements to those of separator device 1 previously described are indicated with the same reference numbers.

In particular, casing 2 of separator 30 comprises a flat base 33 having a ^X8' -shape from a plan view, a side wall 34 perpendicularly exiting from base 33 and an internal wall 35 having the same height as side wall 34 and exiting from base 33 to connect the generating lines reciprocally closest to side wall 34. Internal wall 35 presents respective concave side surfaces so as to define together with side wall 34 two cylindrical chambers 36 and 37 preferably reciprocally equal and having respective axes B and C. Conveniently, side wall 34 defines inlet conduit 4 which exists in transversal sense with respect to axes B and C and communicates directly with chamber 36.

Casing 2 also comprises two exhaust outlets 38 and

39 exiting from base 33 on axially opposite side to side wall 34 for connecting respective chambers 36 and 37 to the internal combustion engine crankcase by means of conduits which will be described briefly below.

Within chamber 36, casing 2 comprises a first tubular element 40 exiting from base 33 and coaxial to axis B.

Tubular element 40 presents a plurality of radial openings 41 adjacent to base 33 and a height equal to that of side wall 34.

Around a base of tubular element 40, casing 2 comprises a plurality of radially and equally spaced walls 42 presenting a height so as to define a supporting plane spaced from base 33 and arranged at a height higher than the maximum dimension of radial openings 41 in direction parallel to axis B. Within chamber 37, casing 2 comprises a second tubular element 43 and a plurality of walls 44 and defines a plurality of openings 45. In particular, walls 44 and openings 45 are equal to those arranged within chamber 36 and tubular element 43 is different from tubular element 40 only in that it comprises an end portion 52 arranged in a higher position with respect to the height of side wall 34.

Preferably, casing 2 is constructed of a single part by moulding.

In use, casing 2 is closed by means of a lid 46 connected to a flange 47 exiting from side wall 34 on the side axially opposite to base 33.

Lid 46 comprises a covering wall 48 axially spaced from internal wall 35 so as to define a passage 49 which fluidically connects tubular element 40 with chamber 37 when casing 2 is closed.

Lid 46 also defines a suction inlet 50 adapted to be connected to the intake manifold and accomodating an end portion 52 by means of a fluid-tight connection.

Separator device 30 also comprises a helical module 53 which works as inertial separator 5 when resting on walls 42 in chamber 36, and a porous filter 6 accommodated in chamber 37 and resting on walls 44.

Conveniently, both helical module 53 and porous filter 6 define respective cylindrical seats 54, 55 to be mounted preferably with interference on tubular element

40 and 43 respectively, and thus be fixed with respect to casing 2.

Preferably, helical module 53 is constructed in a single part by pressing and comprises a tubular body 56 defining seat 54, a helical wall 57 exiting transversally from tubular body 56, and a circular crown 58 exiting radially from a head portion 59 of tubular body 56.

In particular, circular crown 58 fluid-tightly cooperates at least with side wall 34 and internal wall 35 to prevent the intake gas from escaping directly towards passage 49 without running along helical wall 57.

Conveniently, helical wall 57 presents a single principle and defines for each turn a plurality of axial holes 60 adjacent to tubular body 56.

Conveniently, porous filter 6 is constructed by means of a plastic or ceramic material cartridge and comprises a grid 61 with the purpose of increasing the contact surface with the sprayed oil which may adhere and be collected by gravity in the lower part of the device.

In use, the combusted gases rich in oil particles enter casing 2 through inlet 4 which guides the gas input in a tangential direction to favour formation of a rotational motion guided by helical wall 57.

As previously described, after adhering on the walls, the particles are directed towards axial holes 60 and reach exhaust outlet 38 through openings 41 by gravity. After descending towards base 33, the gas flow crosses openings 41 and the direction of flow is inverted, while the flow itself runs up against gravity along tubular element 40, as shown by the dashed-line arrow in figure 2.

Later, the direction of flow is inverted again after gas has crossed passage 49 and descends through porous filter 6 to increase separation.

When the flow reaches base 33, the direction is inverted for the third time and the gas runs up along tubular element 43 through openings 45 to reach the intake manifold.

The oil particles adhere also within porous filter 6 and are directed by gravity onto base 33 and through openings 45 into exhaust outlet 39.

Preferably, exhaust outlets 38, 39 are connected by means of a T-joint to a single conduit 62 which conveys the oil back to the internal combustion engine block.

In this case, exhaust outlet 39 is arranged upstream of a non-return valve 63 to force the flow along tubular element 40 and to avoid it from escaping toward tubular element 43 through exhaust outlet 38 without crossing porous filter 6.

The advantages that the present separator filter allow to obtain are the following.

The use of porous filter 6 arranged in series with inertial separator 5 allows to improve efficiency of the separator device by means of components which are simple, low-cost and easily manufactured by moulding.

Furthermore, the fact that the gas flow crosses annular conduct 17 and tubular element 40 upwards and crosses inertial separator 5 and cartridge filter 6 downwards implies that there are at least two inversions of the direction of the gas flow which allow a further separation by inertia of the oil particles. Separation is further promoted by the fact that also central conduit 16 and tubular element 43 are crossed upwards and therefore require a further inversion of the direction of the gas flow before it reaches the intake manifold. In this way, it is possible to improve efficiency of separator device 1, 30 and to contain both dimensions and costs since the volume of cartridge filter 6 may be reduced.

Furthermore, modularity allows to adapt the separator device to various engine models and to obtain the advantages of scale economy.

The fact that separator sub-module 5a and cartridge sub-module 6a are concentric allows to obtain a compact shape and long pathways for the oil particles which must enlarge by coalescence. Furthermore, making pathways which allow the oil particles formed by coalescence to fall by gravity is simple.

It is finally clear that changes and variations can be made to separator device 1 described and illustrated without departing from the scope of protection of the present invention, as defined in the accompanying claims. For example, according to an embodiment presenting smaller dimensions in the direction transversal to axis A, inertial separator 5 and porous filter 6 form respective modules arranged one beside the other, instead of concentrically.

Deviation wall 12 instead of being helical may present a circular crown shape transversal to axis A and the through holes crossed by the gases and appropriately spaced in tangential direction between two consecutive deviation walls 12. Such simplified configuration further simplifies moulding operations. In use, the appropriate arrangement of through holes imposes sudden changes of direction to the gas, possibly with a rotational component about axis A, in the passage between module 8 and the next one.

Furthermore, porous filter 6 and helical module 53 of separator device 30 may comprise respective sub- modules to adapt the separation efficiency to the type of internal combustion engine without necessarily redesigning the separator.

Non-return valve 63 may be directly joined to exhaust outlet 39 or, for layout reasons, be arranged within a tube which connects exhaust outlet 39 to conduit 62.

Claims

1. A separator device (1) for blow-by gases of an internal combustion engine of a motor vehicle comprising an inlet (3), an outlet (4), an inertial separator (5) interposed between said inlet (3) and outlet (4), characterised in that it comprises a cartridge filter (6) arranged in series with respect to said inertial separator (5) .

2. A separator device according to claim 1, characterised in that said inertial separator (5) and said cartridge filter (6) are crossed downwards by said gas and in that it comprises a first conduit (40) crossed upwards by said gases and arranged between said inertial separator (5) and said cartridge filter (6) .

3. A separator device according to claim 2, characterised in that said first conduit (40) is straight.

4. A separator device according to claims 2 or 3, characterised in that it comprises a second conduit (43) arranged between said cartridge filter (6) and said outlet (4) and crossed upwards by said gases.

5. A separator device according any of the preceding claims, characterised in that said inertial separator (5) comprises first sub-modules (5a) .

6. A separator device according any of the preceding claims, characterised in that said cartridge filter (6) comprises second sub-modules (6a) .

7. A separator device according to claims 5 and 6, characterised in that at least one of said first sub- modules (5a) is coupled to at least one of said second sub-modules (6a) to define an integrated module (8) .

8. A separator device according to claim 7, characterised in that said integrated module (8) defines at least one conduit (16/ 17) for the passage of said gas .

9. A separator device according to one of the claims 7 or 8, characterised in that said integrated module (8) comprises a frame defining a seat (18) for accommodating the respective second sub-module (6a) .

10. A separator device according to any of the preceding claims, characterised in that said inertial separator (5) and said cartridge filter (6) are concentric.

11. A separator device according to any of the claims from 1 to 3, characterised in that said inertial separator (5) and said cartridge filter (6) are arranged side-by-side.

12. A separator device according to claim 11, characterised in that it comprises a casing (2) defining a first exhaust outlet (38) connected to said inertial separator (5) and a second exhaust outlet (39) connected to said cartridge filer (6) .

13. A separator device according to claim 12, characterised in that it comprises a non return valve (63) connected to the most downstream outlet (39) of said first and second exhaust outlets (38, 39) to avoid said inertial separator (5) or said cartridge filter (6) connected to said most upstream outlet (39) from being bypassed when said first and second exhaust outlets (38, 39) are connected to a same oil discharge conduit (62) .

14. A separator device according to any of the preceding claims, characterised in that said cartridge filter (6) comprises a honey comb filter.

15. A separator device according any of the preceding claims, characterised in that said inertial separator (5) is a cyclone separator.

16. A separator device according any of the claims from 1 to 14, characterised in that said inertial separator (5) is an impact separator.

17. A separator device according any of the preceding claims, characterised in that said cartridge filter (6) is arranged downstream of said inertial separator (5) .