WO2015052693A1

WO2015052693A1 - Device for separating solid particles from the exhaust gases of an engine

Info

Publication number: WO2015052693A1
Application number: PCT/IB2014/065270
Authority: WO
Inventors: Michel Deneire
Original assignee: Darvan Invest N.V.
Priority date: 2013-10-11
Filing date: 2014-10-13
Publication date: 2015-04-16
Also published as: BE1021830B1

Abstract

A filter device (1) for separating solid particles from the exhaust gases of a combustion engine comprises a housing (28) with on the one side at least one inlet (41) for direct coupling to at least one outlet (4) of a combustion engine, and, on the other side an outlet (49) for the filtered exhaust gases (38) into the environment, and between them at least one filter chamber (30) with a highly porous filter plate (34, 42), rotatably mounted about its axle (32), for trapping and removing the solid particles from the exhaust gases. Spray means (35) supply a treatment fluid (36) for moistening the filter plate (42) and for said binding and removal of the separated solid particles along with the spray fluid into an emptiable storage space (29).

Description

DEVICE FOR SEPARATING SOLID PARTICLES FROM THE EXHAUST GASES OF AN ENGINE

TECHNICAL FIELD OF THE INVENTION The invention relates to a device for separating solid particles from the exhaust gases of a combustion engine, hereinafter referred to in short as a soot particle filter. With the sharp increase in freight traffic with powerful diesel engines, air pollution through exhaust gases with inadequately filtered out soot particles has become a global public health problem, particularly in the vicinity of densely populated regions. In today's combustion engines ever more injectors are currently being used to atomise the fuel into mists of increasingly fine droplets at very high pressure. This encourages faster ignition, but at the same time creates more ultra-fine, sub- micron particles. It has now been established that it is precisely these minute soot particles with measurements in the sub-micron range that are the most harmful to health and that they are presently still not being adequately filtered from the exhaust gases of diesel and petrol engines and are seriously and dangerously contaminating the air.

STATE OF THE ART

To remove particles from air, combustion gases and other exhaust gases, it has long been known to pass the particle-laden gas flow through a spiral channel space. The space then acts as a cyclone whereby the heavier particles are forced against the inner wall of the channel by centrifugal force. The cleaned gas flow is then removed from the more centrally located zone of the channel space. From DE-2835741 a soot particle filter for exhaust gases of combustion engines is known. In it, onto the inner wall of a thermally insulated silencer a heat-resistant filter cloth is applied for trapping the centrifugally separated soot particles. The gas flow then returns close to an additionally heated end of the silencer in a central outlet pipe for the cleaned gas. The additional heating is thereby intended to burn off the soot in the exhaust system itself.

BRIEF DESCRIPTION OF THE INVENTION

It is now a primary aim of the invention to create a soot particle filter which removes sub-micron soot particles from the exhaust gases with a high degree of efficiency. In addition, for the first time the invention allows this to be done in a way that is not mechanically complicated and without the use of helical flow spaces, costly catalytic converters or additional heating of the exhaust system. An additional aim is to create means of easily removing the filtered soot particles from the exhaust system and to collect them for disposal in a more or less bound, less harmful form. More particularly, the treatment is intended to prevent any harmful effects on the environment through the distribution of fine material after filtering. In a first aspect the present invention envisages a filter device for separating solid particles from the exhaust gases of a combustion motor. The filter device comprises a housing with, on the one hand, at least one inlet for direct connection to at least one outlet of a combustion engine, and, on the other hand, an outlet into the environment for the filtered gases. The filter device also comprises an emptiable storage space for the separated particles in a more or less bound or compacted form. The housing also comprises at least one filter chamber to which the at least one inlet for the exhaust gases to be filtered and the outlet for the filtered gases connect. In the at least one filter chamber, between said inlet and outlet, a highly porous motor-driven filter plate is provided, rotatably mounted around its axle, for trapping and separating the solid particles from the gases. The filter device also comprises spray means for spraying a treatment fluid for moistening the filter plate and for said binding and removal of the filtered solid particles along with the spray fluid to said storage space.

In embodiments of the present invention the housing of the filter device only comprises one filter chamber. In alternative embodiments of the invention the housing comprises a plurality of filter chambers, for example a first filter chamber and a second filter chamber. Both filter chambers can simultaneously treat a different gas flow. Alternatively both filter chambers can provide a different degree of cleaning of a gas, and the outlet of the first chamber can be connected to the inlet of the second chamber, whereby an already partially cleaned gas that leaves the first chamber is cleaned further in the second chamber. For this the porous filter plates can, for example, have a different degree of porosity in the first and second chamber, for example in that they are made of different materials or in that they are made of the same material but with a different density. If different filter chambers of a filter device in accordance with the present invention simultaneously treat different gas flows, an outlet channel of the second filter chamber can discharge into an outlet channel of the first filter chamber. The outlet channels can then be dimensioned and positioned in such a way that when the exhaust gases flow through them a suction effect is brought about at the discharge opening of the second outlet channel into the first outlet channel.

In a filter device according to embodiments of the present invention the highly porous filter plate can comprise a metal-foam structure or a fibrous web. Given the intended use of the filter device in exhaust gases of a combustion engine, the filter plate should preferably be heat- resistant, at least up to temperatures in the region of prevailing temperatures of exhaust gases.

A filter device in accordance with embodiments of the present invention can also comprise first detection means for determining when the highly porous filter plate has to be cleaned. Such detection means can, for example, be pressure sensors that indicate when, with a same gas flow, the pressure in chamber exceeds a pre-set pressure, because the filter plate becomes more and more clogged with filtered out particles.

A filter device in accordance with embodiments of the present invention can also comprise second detection means for determining when the storage space in which the filtered out particles are stored in compacted form, has to be emptied.

The device provided in accordance with the invention can be coupled to the silencer of a combustion engine, or to an outlet opening of an upstream filter device, for the temporary storage of the particles separated out in the device. For this, the filter device in accordance with the present invention comprises a housing with an emptiable storage space for the separated particles in more or less compacted form.

Specific and preferable aspects of the invention are set out in the attached independent and dependent claims. Features of the dependent claims can be combined with features of the independent claims and with features of further dependent claims as appropriate, and not only as expressly set out in the claims. To summarise the invention and the attained advantages with regard to the state of the art, certain aims and advantages of the invention have been described above. It should of course be understood that not necessarily all these aims or advantages can be achieved by each specific embodiment of the invention. Thus, for example, persons skilled in the art will realise that the invention can be embodied or implemented in a way which achieves or optimises one advantage or a group of advantages as set out herein, without necessarily achieving other aims or advantages that may be set out or suggested herein.

The above and other aspects of the invention will be clarified and explained with reference to the embodiment(s) described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described further by way of an example relating to an embodiment of the device according to the invention? with reference to the attached drawings. It is self-evident that the protection is not restricted to this embodiment. It is only to be seen as an example for explaining the claimed scope of protection.

FIG. 1 shows a perspective view of a filter device for separating solid particles in accordance with an embodiment of the present invention.

FIG. 2 shows the opposite side of the filter device according to figure 1.

FIG. 3 shows a filter device in accordance with embodiments of the present invention, coupled as a subsequent treatment filter downstream of another filter device.

FIG. 4 shows the filter device of FIG. 3 seen from the rear.

The drawings are only schematic and not limiting. In the drawings the dimensions of some components may be shown as exaggerated and not to scale for illustrative purposes. Dimensions and relative dimensions do not necessarily correspond with actually implemented embodiments of the invention. Reference numbers in the claims must not be interpreted in order to restrict the scope of protection. In the various drawings the same reference numbers denote the same or similar elements. DETAILED DESCRIPTION

The terms first, second and suchlike in the description and in the claims are used to distinguish elements of the same kind and not necessarily to describe a sequence neither in time, nor space nor order nor in any other manner. It must be understood that in this way the terms can be interchangeably used in certain circumstances and that the embodiments of the invention described therein are able to function in an order that is different from that described or set out here.

In addition, the terms top, bottom, above, before etc. in the description and claims are used for descriptive purposes and not necessarily to describe relative positions. It must be understood that the terms used like this can under certain circumstances be interchanged and that the embodiments described herein can also work in accordance with orientations other than described herein. It should be noted that the term "comprises" as used in the claims should not be interpreted as being restricted to the means described thereafter; this term does not exclude any other elements or steps. It should be interpreted as specifying the presence of the stated features, values, steps or components to which reference is made, but does not exclude the presence or addition of one or more other features, values, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices that only consist of means A and B. It means that with reference to the present invention, A and B are the only relevant components of the device.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a specific feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the occurrence of the expressions "in one embodiment" or "in an embodiment" at various places throughout this specification does not necessarily all refer to the same embodiment, but certainly can do. Furthermore, the specific features, structures or characteristics can be combined in any suitable manner in one or more embodiments, as should be clear to an average person skilled in the art on the basis of this disclosure.

Similarly it must be appreciated that in the description of the exemplary embodiments of the invention, various features of the invention can sometimes be grouped together in one single embodiment, drawing or description thereof with the aim of streamlining the disclosure and helping to understand one or more of the plurality of inventive aspects. This method of disclosure should not in any way be interpreted as a reflection of an intention for the invention to require more features than explicitly set out in each claim. Rather, as the following claims show, there are inventive aspects in fewer than all features of a single previously disclosed embodiment. Thus, the claims following the detailed description, are explicitly included in this detailed description with each individual claim as a separate embodiment of this invention.

Also, while some embodiments described herein include some, but not other, features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention and form these different embodiments as would be understood by a person skilled in the art. For example, in the following claims any of the described embodiments can be used in any combination. In the description provided here, numerous specific details are brought forward. It must be understood that embodiments of the invention can be implemented without these specific details. In other cases well-known operating procedures, structures and techniques are not shown in detail in order to keep this description clear. A filter in the context of the present invention is an apparatus that ensures that drawn in gas (gas originating from a combustion engine) is cleaned of undesirable substances.

FIG. 1 and FIG. 2 outline the device 1 according to the invention for separating solid particles from the exhaust gases of a combustion engine. The fuel of the combustion engine can be diesel, petrol or gas. The device is generally placed close to the outlet system for the hot exhaust gases of the engine.

Such a filter device 1 is particularly useful for private cars (e.g. with a diesel engine). This filter device 1 essentially concentrates the particles 5 into a more or less compacted mass 46 (sediment) and temporarily stores it in the bottom of an emptiable storage space 29 in the housing 28 of the filter device 1. The compacted particle mass 46 can then periodically be easily removed from the storage space 29 as described below. The filter device 1 is intended to be coupled by way of an inlet coupling 41 to an outlet 4 for exhaust gases from a combustion engine, for example to a silencer of a combustion engine.

The filter device 1 comprises a filter chamber 40 in a housing 28 with the inlet coupling 41 for connection to an outlet of a combustion engine, for example to a silencer of a combustion engine. In the filter chamber 40 is a highly porous filter plate 42. This is mounted on an axle 32 and can be rotated by means of a motor 33, for example an electric motor drive. At the top of the filter chamber 40 spray means 35 are arranged for applying a fluid 36 for moistening the filter plate 42. Further, an outlet channel 43 is mounted for evacuating the cleaned residual gas 44 from the filter chamber 40.

The filter plate 42 can, for example, be of a metal-foam structure or can comprise a (temperature-resistant) fibrous web. Metal foam is metal made up of a clear cellular structure. The most widely used metal for metal foam filter plates is aluminium, or alloys of aluminium, but the invention is not restricted thereto. Metal foam has hollow spaces, which lower the density of the material and allow a gas flow to be pressed through the material, while the rigidity of the metal material is maintained. Fibrous web is material made of textile fibres which are mechanically and/or chemically and/or thermally bonded into webs without the use of weaving or knitting methods. It is known that the particles to be separated, more particularly soot particles, easily adhere (stick, adsorb) to the moistened pore walls of such filter plates 42. The sprayers 35 for the filter chamber can be fed via a circulation pump for the fluid 36. This fluid 36 is in fact a washing fluid that is able to wash the particles that have been separated and held in the filter plates, out of the pores of the filter plates.

The filtering takes place as follows. A heavily particle-laden gas flow from the combustion engine is fed via the inlet coupling 41 to the filter chamber 40. The numerous particles are trapped and held in the filter plate 42. Through this the filter plate 42 becomes denser and the pressure in the filter chamber 40 will increase. When the pressure in the filter chamber 40 reaches or exceeds a predefined admissible pressure, suitable detectors, that are known in themselves and are appropriately mounted (not illustrated), will send a signal to the sprayers 35 to discharge their washing fluid 36 onto the outer surface of the filter plate 42 involved. At the same time the detectors send a signal to the motor drive 33 for the rotation axle 32 to let the filter plate 42 turn slowly so that it is fully moistened (saturated) with the washing fluid 36 whereby the particles held in the filter plate are loosened from its pores.

At this point the detectors send another signal to let the filter plate 42 rotate more quickly for a short period so that the trapped particles are centrifugally whirled out with the washing fluid 36 against the inner wall of the housing 28 of the filter chamber 40. The particle-laden washing fluid 36 then drips down along the wall into the storage space 29 where the particles settle. The washing fluid 36 rises to the surface in the space 29 in order to be taken up and returned by the circulation pump to the sprayers 35. When the deposit of particles compressed into a type of paste reaches a sufficient filling level in the storage space 29 (indicated by a sensor for example) this mass has to be allowed to flow out (tapped), for example via a discharge channel 47. This will of course preferably take place when the vehicle is stopped and the combustion engine is switched off. FIG. 3 and FIG. 4 show a front view and a rear view respectively of an alternative filter device 27, wherein a first and a second filter chamber 30, 40 according to the present invention are coupled one after the other. Each filter chamber 30, 40 forms part of a filter device as described in relation to FIG. 1 and FIG. 2, and like components have the same or similar features, even though these are not described again below.

Each filter chamber 30, 40 has a housing 28 with an inlet coupling 31, 41, each intended to be coupled to an outlet 4a, 4b of a combustion engine, in order to thus receive a particle-laden gas flow in the respective filter chambers 31, 41. One filter chamber 30 comprises a highly porous filter plate 34 that can be rotated about its axle 32, and the other filter chamber 40 comprises a highly porous filter plate 42 that can be rotated about its axle 32. The highly porous filter plates 34, 42 are as previously described in relation to the filter device 1. The rotatable axle 32 can be driven by a motor 33, for example an electric motor drive. Preferably both filter plates 34, 42 are mounted on the same axle (as illustrated in FIG. 3 and FIG. 4) but this is not obligatory. The highly porous filter plates 34, 42 can each be mounted on a different, separately driven axle. In the latter case the axles can each be driven by their own motor, or via a separate transmission, by the same motor.

Arranged in each of the filter chambers 30, 40 are spray means 35 for applying fluid to moisten the filter plates 34, 42. During operation of the filter the particles to be separated adhere to the moistened filter plates 34, 42. After filter operation, during the cleaning of the filter plates 34, 42 via the spray means 35 washing fluid is spread out over the filter plates 34, 42 in order to remove the particles held in the filter plates 34, 42 from these filter plates. Both filter chambers can be separated from each other by a partition 48.

Via the inlet couplings 31, 41 two different gas flows originating from two different outlets 4a, 4b, can be supplied to two different filter chambers 30, 40. The gas flow can have different levels of contamination. The gas flows can also have different flow rates.

The gas flow cleaned in the first filter chamber 30 is fed via a removal element 37 to an outlet channel 39 for cleaned gas. The gas flow cleaned in the second filter chamber 40 is removed from the filter chamber via an outlet channel 43 for cleaned gas. Both outlet channels can be connected to each other, or can discharge separately. If, as shown in FIG. 3, a cleaned residual gas 44 with a low flow rate is directed via a pipe 43 into a larger channel 39 a suction effect (Venturi) occurs at the discharge opening 45 of the pipe 43 in the channel 39. Through this effect the cleaned residual gas 44 is drawn out there into the flow 38 of gas cleaned in the first filter chamber. The cleaned gas flows are released into the outside environment via an outlet opening 49.

One of the two filter plates 34, 42 may reach its admissible pressure level earlier than the other one. If both filter plates 34, 42 can be driven separately, they can undergo a separate cleaning action. If not, they should preferably be cleaned at the same time. As in the filter device 1 with one single filter chamber 40, the particles trapped by the filter plates 34, 42 are washed out of the filter plates 34, 42, flushed away and concentrated to a more or less compacted mass 46, which is stored and settles in a storage room 29. Both filter chambers 30, 40 can, but do not have to, use one and the same storage space 29. The compacted particle mass 46 can periodically be easily removed from the storage space(s) 29 via a removal pipe 47.

EXAMPLE

The analysis of the particles trapped in the compacted mass 46 in the storage space 29 of the filter device 1 or 27 indicates the presence of soot particles PM-10 which can be recycled from this mass and can be recovered for adding as a filler to rubber, for e.g. tyres. PM-1 particles can also be used and recovered as a binding agent, and thus as a strengthening agent for such rubber due to their known irregular (lobular) surface. The trapped soot can therefore be reused in a useful and environmentally-friendly way.

The invention is of course not restricted to the embodiments described above. Variations is composition and design of the filter devices 1, 27 and its components for practically the same functions are conceivable which are evident to a person skilled in the art. The invention and the scope of protection therefore particularly also include these and all other embodiments as described below in the attached claims.

In embodiments of the device in question, the filter device 1 can be directly coupled with an inlet coupling 41 to the silencer behind (and under) the car, and with an outlet opening 49 to the environment for the cleaned combustion gases. The filter device 1 then functions as actual separator of particles, more particularly of soot particles into storage space 29.

Claims

Filter device (1, 27) for separating solid particles from the exhaust gases of a combustion engine, said device (1, 27) comprising a housing (28) which on the one side has at least one inlet (31, 41) for direct coupling to at least one outlet (4; 4a, 4b) of a combustion engine and, on the other side, an outlet (49) for discharging the filtered exhaust gases (38) into the environment, as well as an emptiable storage space (29) for the separated particles in a more or less bound or compacted form (46), and wherein the housing (28) also comprises at least one filter chamber (30, 40) to which the at least one inlet (31, 41) for exhaust gases to be filtered and the outlet (49) for the filtered gases are connected; with, in the at least one filter chamber (30, 40), between said inlet (31, 41) and outlet (49), a highly porous filter plate (34, 42), which is rotatably mounted around its axle (32) via a motor drive (33), for trapping and separating the solid particles from the exhaust gases; and with spray means (35) for a treatment fluid (36) for moistening the filter plate (34, 42) and for said binding and removal of the separated solid particles with the spray fluid to the said storage space (29).

Filter device (1) according to claim 1, wherein the housing (28) only comprises one filter chamber (40).

Filter device (27) according to claim 1, wherein the housing (28) comprises a first filter chamber (30) and a second filter chamber (40).

Filter device (27) according to claim 3, wherein an outlet channel (43) of the second filter chamber (40) discharges into an outlet channel (39) of the first filter chamber (30).

Filter device (27) according to claim 4, wherein the outlet channels (43, 39) are dimensioned and positioned in such a way that when the exhaust gases flow through them a suction effect is brought about at the discharge opening (45) of the outlet channel (43) in the outlet channel (39).

Filter device (1, 27) according to any one of the preceding claims, wherein the highly porous filter plate (34, 42) comprises a metal-foam structure or a fibrous web.

Filter device (1, 27) according to any one of the preceding claims, which also comprises first detection means for determining when the highly porous filter plate (34, 42) has to be cleaned.

Filter device (1, 27) according to any one of the preceding claims, which further contains second detection means for determining when the storage space (29) has to be emptied.