"Separator device for blow-by gases"

Field of application

[0001] The present invention relates to a separator device for blow-by gases, i.e. the oil vapors vented from the crankcase of internal combustion engines during their functioning; typically, such gases thus consist of air and suspended particles, comprising oil droplets and/or soot (from the internal combustion engine) . The present invention further relates to a separator assembly for blow-by gases comprising such separator device and an engine group comprising an internal combustion engine and such blow-by gas separator assembly.

Prior art

[0002] In the prior art, separation assembly solutions connectible to the crankcase and suitable to vent the blow-by gases therefrom are known. Specifically, solutions of assemblies which filter the blow-by gas and then recirculate it towards the engine and/or towards the engine exhaust are known. In a preferred embodiment, such separation assemblies are fluidically connected to the air intake circuit, e.g. downstream of the main filter suitable to treat the combustion air or, if envisaged, upstream of the compressor. As a consequence, it is very important for the blow-by gas to be effectively filtered before being circulated, i.e. for the air to be effectively separated from the suspended particles to avoid the formation of amorphous coatings which typically cause damage to the engine valves and/or to the parts which form the turbocharger.

[0003] Many solutions of separator assemblies, envisaging a static filter, which is crossed by the gas and is suitable to retain the suspended particles, are known in the prior art .

[0004] Other known solutions of centrifugal separator assemblies are known, which have moving, in particular rotating, filtering devices, so that such rotation causes the separation between air and suspended particles.

[0005] An example of such solutions is shown in document TO2002A000358, which illustrates a filtering unit permeable to air which is moved in rotation. Another example is shown in document TO2006A000351, which instead describes a device which has an impeller, which is moved in rotation, and a conveying element, suitable to operate with said impeller to perform a centrifugal separation of the particles suspended in air.

Solution of the invention

[0006] In the optimization of the components of a motor vehicle and of its operation, the need is strongly felt to make available a separator assembly device which is as efficient in the air/suspended particle operations as possible with a solution which is as less complex as possible .

[0007] It is an object of the present invention to provide a new alternative, improving embodiment of the separator device suitable to filter the blow-by gas separating the particles suspended by the gaseous current.

[0008] Such object is achieved by means of the separator device claimed according to claim 1, by means of a separator assembly comprising such separator device according to claim 14 and by means of an engine group comprising a separator assembly according to claim 16. The claims dependent on these show preferred variant embodiments implying further advantageous aspects.

Description of the drawings

[0009] Further features and advantages of the invention will be apparent from the description provided below of preferred embodiments thereof, given by way of non- limiting examples, with reference to the accompanying drawings, in which:

[0010] - figure 1 shows a diagrammatic section view of a separator assembly according to a preferred embodiment which comprises a filtering device;

[0011] - figure 2a shows a perspective view of a separator device of the present invention according to a first preferred embodiment;

[0012] - figures 2b and 2c show a cross section and a front view of the separator device shown in the figure 2a, respectively;

[0013] - figure 3a shows a perspective view of a separator device of the present invention according to a second preferred embodiment;

[0014] - figures 3b and 3c show a cross section and a front view of the separator device shown in the figure 3a, respectively;

[0015] - figure 4a shows a perspective view of a separator device of the present invention according to a third preferred embodiment;

[0016] - figures 4b and 4c show a cross section and a front view of the separator device shown in the figure 4a, respectively;

[0017] - figures 5 and 6 show two further embodiments of the separator device in section view, respectively.

Detailed description

[0018] With reference to the attached figures, reference numeral 500 indicates as a whole a separator assembly for blow-by gases, suitable to separate the air from the suspended particles, fluidically connected to the crankcase of an internal combustion engine. Preferably, the separator assembly 500 is installable in an appropriately shaped housing.

[0019] The separator assembly 500 comprises a casing 501, which identifies a separation chamber 510 within having an inlet mouth 511 of the blow-by gases and an outlet mouth 512 of the filtered gases. Furthermore, the separator assembly 500 includes a draining opening (not shown) arranged on the bottom of the casing 501, that means on the bottom of the separation chamber 510, suitable to allow the return of separator oil towards the crankcase.

[0020] According to a preferred embodiment, the separator assembly 500 extends along a main development axis, which preferably coincides with the axis X-X (described below) , so that the inlet mouth 511 is placed on a side wall of the casing 501 and the outlet mouth 512 is preferably placed on a front or rear wall of the casing 501 perpendicular to the development axis, and thus perpendicular to the development axis X-X.

[0021] Furthermore, the separator assembly 500 comprises a separator device 1, which is in turn the object of the present invention.

[0022] Preferably, said separator device 1 is suitable to be housed in said separation chamber 510, in which it is suitable to perform the blow-by gas separation or filtering action. [0023] According to a preferred embodiment, the separator device 1 is suitable to be moved in rotation along an axis X-X; indeed, the separator device 1 is preferably suitable to be operatively connected to movement means such to guide its rotary movement. For example, the separator device 1 is movable in rotation by a specific motor, e.g. an electrical motor, or is operatively connectable to the respective internal combustion engine, e.g. to its camshaft.

[0024] According to a preferred embodiment, the separator device 1 comprises a rotating shaft 4 which is engageable by said moving means for controlling the rotation of the separator device 1 about the axis X-X.

[0025] According to a preferred embodiment, the filtering device 1 substantially comprises two main components: a filtering unit 2, suitable to filter the air, and a deviation unit 3, suitable to perform a specific action on the intake air. Preferably, the rotating shaft 4 is operatively connected both to the filtering unit 2 and to the deviation unit 3 to guide them in rotation; in a preferred embodiment, the rotating shaft 4 is indeed co- molded with the deviation unit 3.

[0026] According to a preferred embodiment, the action of the separator device 1 on the blow-by gas filtering is thus as a function of the operating variables of the separator device 1 as a whole, such as its rotation speed, but also of the specific components, such as, for example the permeability of the filtering unit 2 or the particular geometry of the deviation unit 3.

[0027] Preferably, the filtering unit 2 extends hollow along said axis X-X and is radially traversable by the blow-by gases being permeable to air while the suspended particles are blocked; preferably, the filtering unit 2 allows the filtering of the blow-by gases radially from the outside inwards. In other words, said filtering unit 2 is of the ring type, identifying a central cavity 20, and performs the filtering action radially.

[0028] According to a preferred embodiment, the diversion unit 3 extends, in turn, along axis X-X and surrounds the filtering unit 2.

[0029] Preferably, the deviation unit 3 is suitable to delimit therein a housing 32 in which the filtering unit 2 is housable.

[0030] For example, the diversion unit 3 is bell-shaped, comprising a bottom wall 300 on which the filtering unit 2 rests and a side wall 310 which surrounds it. Preferably, the deviation unit 3 also comprises a cap 301 suitable to close the housing 32. In other words, the filtering device 3 has a cage-like structure suitable to contain the filtering unit 2. [0031] According to a preferred embodiment, the deviation unit 3 comprises a plurality of diverting elements 31 arranged circumferentially with respect to the filtering unit 2 and mutually and angularly separated, e.g. obtained on said side wall 310.

[0032] Preferably, each deviation element 31 extends in length in a distal direction starting from the filtering unit 2. In other words, the deviation unit 3, in particular its deviation elements 31, extends in length from the filtering unit 2, to a region circumferential thereto .

[0033] Preferably, each deviation element 31 extends along the axis X-X by a length substantially equal to the thickness of the filtering unit 2.

[0034] So, in a preferred embodiment, the deviation unit 3 is substantially a radial impeller, in which the deviation elements 31 act as radial blades.

[0035] The deviation unit 3 is thus suitable to perform a specific action on the intake blow-by gases via the filtering unit 2. Preferably, the action performed by the deviation unit 3 is as a function of the number, of the arrangement and of the shape of the deviation elements 31.

[0036] In a preferred embodiment, each deviation element 31 radially extends in length from the filtering unit 2 (as shown by way of example in figures 2a, 2b and 2c) .

[0037] Preferably, each deviation element has a length comprised between 2 and 25 mm, for example.

[0038] In other words, in such embodiment, the deviation unit 3 is suitable to perform an action on the blow-by gas, in a direction tangential to the filtering unit 2; in other words, such action creates a vortex effect about the filtering unit 2. So, such action creates a boundary layer and a higher centrifugal force than the centrifugal force experienced by the gas in a configuration of the separator device without any deviation unit, so that the separator device 1 displays a greater separation efficiency .

[0039] In other embodiments, the filtering unit 2 of the type comprising a folded filtering medium or a porous depth septum.

[0040] Instead, in a further preferred embodiment, each deviation element 31 is tilted with respect to a radial direction by a positive angle a. In other words, each deviation element 31 is tilted in the same direction as that of rotation of the separator device 1. A first example of such embodiment is shown in figures 3a, 3b and 3c. A second example of such embodiment is shown in figures 4a, 4b and 4c.

[0041] Preferably, each deviation element 31 has a substantially convex or substantially concave curvilinear pattern .

[0042] In other words, in such embodiment, the deviation unit 3 is suitable to perform an action on the blow-by gas, in a tilted direction towards the filtering unit 2; in other words, such action pushes the blow-by gas towards the filtering unit 2. So, such action creates an increase of the flow of blow-by gas through the filtering unit 2, thus determining an increase of crossing speed of the air through the filtering unit 2.

[0043] Preferably, in such embodiment, the filtering unit 2 is of the high filtering efficiency type, for example of the pleated filter type, closed in the shape of a star or a porous depth septum consisting of fibrous synthetic material .

[0044] In other words, the increase of gas speed makes it possible to use a more efficient and/or less permeable filtering unit 2 without altering the total differential pressure which is measureable straddling the separator device 1 with respect to the embodiments of the prior art without deviation elements 31, or the embodiment described above of the deviation device 3 with radial deviation elements 31, in which a clear variation of flow crossing the filtering unit 2 or of the crossing speed of the filtering unit 2 is not determined. [0045] In yet other words, the filtering unit 2 is suitable to prevent the passage of smaller sized suspended particles, considerably increasing the efficiency of the separator device 1.

[0046] Instead, according to a yet further preferred embodiment, each deviation element 31 is tilted with respect to a radial direction by a negative angle β. In other words, each deviation element 31 is tilted in the opposite direction with respect to the sense of rotation of the separator device 1.

[0047] Preferably, each deviation element 31 has a substantially convex or substantially concave curvilinear pattern .

[0048] In other words, in such embodiment, the deviation unit 3 is suitable to perform an action on the blow-by gas, in a tilted direction away from the filtering unit 2; in other words, such action pushes the blow-by gas in a direction opposite to the filtering unit 2. Such action thus creates a decrease of the blow-by gas flow towards the filtering unit 2, increasing the action of the centrifugal force.

[0049] In other words, the deviation unit 3 causes a decrease of the flow speed crossing the filtering element. This decrease of speed makes it possible to use a less efficient filtering unit 2, having higher air permeability, capable of offering less resistance to the passage of air without altering the total pressure drop which can measured straddling the separator device 1 with respect to the embodiments of the prior art without deviation elements 31, or the embodiment described above of the deviation device 3 with radial deviation elements 31, in which a clear variation of flow crossing the filtering unit 2 or of the crossing speed of the filtering unit 2 is not determined.

[0050] In other words, the filtering unit 2 has an increase of permeability or porosity, increasing the amount of particulate which is accumulated by the filtering unit during the service life, which is therefore longer.

[0051] Preferably, in such embodiment, the filtering unit 2 has a low filtering efficiency, for example of the pleated filter type, closed in the shape of a star or a porous depth septum consisting of fibrous synthetic material .

[0052] It is a further object of the present invention an engine group comprising an internal combustion engine and a separator assembly according to that described above.

Preferably, the internal combustion engine has a specifically shaped housing in which the separator assembly is placed.

[0053] In innovative manner, the blow-by gas separator device and the blow-by gas separator assembly which comprises it thoroughly fulfills the object of the present invention providing an effective solution which is alternative to the typical blow-by filter solutions of the prior art.

[0054] Indeed, the separator device is advantageously suitable to filter the blow-by gas, effectively separating the particles suspended by the air.

[0055] Furthermore, the deviation unit is advantageously suitable to perform an action on the blow-by gas such to improve the separation action, and thus the filtering action, of the filtering unit.

[0056] A further advantageous aspect resides in that different filtering unit types are envisaged as a function of the deviation unit type. So, by virtue of the synergistic action of the filtering unit and of the deviation device, the separator device is advantageously suitable to obtain surprising blow-by gas separation and filtering results.

[0057] In a yet further advantageous aspect, the separator device is simple to make and its assembling and installation is not complex.

[0058] Advantageously, the separator device, comprising a deviation unit substantially surrounding the filtering unit as a cage does not have high inertia moments. [0059] It is apparent that a person skilled in the art, to satisfy contingent needs, may make changes to the separator assembly and to the separator device described above, all of which are contained within the scope of protection as defined in the following claims.

[0060] Reference number list:

1 separator device

2 filtering unit

3 deviation unit

31 deviation element

32 housing

300 back wall

310 side wall

301 cap

4 rotating shaft

X-X rotation axis

a positive angle

β negative angle

500 separator assembly

501 casing

510 separation chamber

511 inlet mouth

512 outlet mouth