WO2006125516A1 - Highly effective non-clogging filter unit - Google Patents

Highly effective non-clogging filter unit Download PDF

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Publication number
WO2006125516A1
WO2006125516A1 PCT/EP2006/004253 EP2006004253W WO2006125516A1 WO 2006125516 A1 WO2006125516 A1 WO 2006125516A1 EP 2006004253 W EP2006004253 W EP 2006004253W WO 2006125516 A1 WO2006125516 A1 WO 2006125516A1
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WO
WIPO (PCT)
Prior art keywords
filter
filter unit
exhaust gas
flow
shunts
Prior art date
Application number
PCT/EP2006/004253
Other languages
German (de)
French (fr)
Inventor
Martin Votsmeier
Jürgen GIESHOFF
Thomas Kreuzer
Original Assignee
Umicore Ag & Co. Kg
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Umicore Ag & Co. Kg filed Critical Umicore Ag & Co. Kg
Priority to EP06753509A priority Critical patent/EP1902202A1/en
Priority to JP2008512718A priority patent/JP2008540933A/en
Publication of WO2006125516A1 publication Critical patent/WO2006125516A1/en

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0871Regulation of absorbents or adsorbents, e.g. purging
    • F01N3/0878Bypassing absorbents or adsorbents
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D46/00Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/56Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition
    • B01D46/62Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition connected in series
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0093Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are of the same type
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0097Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/011Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel
    • F01N13/017Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more purifying devices arranged in parallel the purifying devices are arranged in a single housing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/022Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
    • F01N3/0222Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/031Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters having means for by-passing filters, e.g. when clogged or during cold engine start
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2273/00Operation of filters specially adapted for separating dispersed particles from gases or vapours
    • B01D2273/10Allowing a continuous bypass of at least part of the flow, e.g. of secondary air, vents
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2279/00Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses
    • B01D2279/30Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses for treatment of exhaust gases from IC Engines
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/20Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a flow director or deflector
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2340/00Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the apparatus; Spatial arrangements of exhaust apparatuses
    • F01N2340/02Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the apparatus; Spatial arrangements of exhaust apparatuses characterised by the distance of the apparatus to the engine, or the distance between two exhaust treating apparatuses

Definitions

  • the invention relates to a blockage-free filter unit for removing soot from the exhaust gas of diesel engines.
  • Exhaust systems with a particle filter are known.
  • a problem with the operation of particle filters is the increase of the exhaust gas backpressure due to the soot already deposited in the filter. In the worst case, the back pressure can rise so high that it comes to a standstill of the engine.
  • Conventional soot filters must therefore be regenerated from time to time, that is, the soot deposited on them must be burned. With a high soot loading, the combustion heat of the soot can destroy the filter. Regular regeneration prevents this.
  • the ignition temperature of the soot can be reduced by the use of catalytically active fuel additives or by catalytic coating of the filter to about 400 0 C, but even with catalytic activation, the ignition temperature of the soot is achieved only in certain operating conditions of the engine.
  • the soot load of the filter must be monitored consuming by the engine control and, if necessary, a filter regeneration can be initiated by an active increase in the exhaust gas temperature. This active filter regeneration inevitably requires increased fuel consumption. The amount of fuel to be expended for the regeneration measures is additionally increased by the uncertainty in the calculation of the filter load and the necessary safety reserves.
  • the retrofit filter must ensure a clog-free operation even with long time passive regeneration passive.
  • the opening of the shunt is arranged at a location of the front end face of the particle filter, which is not or only slightly flowed through by the particle-laden exhaust gas.
  • EP 0 879 938 A2 European published patent application EP 0 879 938 A2.
  • German Patent Application DE 198 55 093 A1 describes a system consisting of two filter elements arranged one behind the other. A partial flow is passed in a shunt on the front filter element and cleaned in the rear element. Another partial stream is cleaned in the front element and passed in a shunt on the rear element. Very similar systems are also described in US Pat. Nos. 6,464,744 B2 and 4,625,511.
  • US Pat. No. 4,625,511 discloses a system with two filters arranged one behind the other, with only the first filter being shunted. A similar system is also described in German Offenlegungsschrift DE 101 51 698 A1. The advantage of these systems is that a more uniform loading of the two filters is achieved with soot.
  • the present invention discloses an open, and thus blockage-free, filtration unit with good filter efficiency for the removal of soot from the exhaust of diesel engines.
  • the filter unit consists of at least two filter units which are interlinked at a distance and are flowed through in succession by the exhaust gas.
  • the filter unit is characterized in that each filter unit has one or more shunts, which are laterally offset from each other in two successive filter units and wherein there is a blockage-free flow path between the shunts of the successive filter units.
  • Each filter unit thus contains a particle filter and one or more shunts through which a portion of the exhaust gas can pass unfiltered through the associated filter unit.
  • the shunts can be arranged both inside the respective particle filter or externally. According to the invention there is a blockage-free flow path between the shunts of two successive filter units, so that even in the case of a complete blockage of the filter, the exhaust gas can flow unhindered through the shunts through the filter unit.
  • the shunts of two successive filter units are laterally offset from each other, so that the exhaust gas fractions, which have flowed through the front particulate filter and cleaned, preferably flow through the shunts of the subsequent filter unit, while the exhaust gas components from the shunts of the front filter unit preferably through the rear particulate filter stream.
  • Figure 1 Inventive filter unit with external shunts: flow conditions in filters with low soot loading
  • Figure 2 Inventive filter unit with external shunts: flow conditions in filters with high soot loading
  • Figure 3 Filter unit of Figure 1 with outlet A of the first shunt in the flow direction of the exhaust gas behind the inlet E of the second shunt
  • Figure 4 filter unit of Figure 1 with arranged in the shunts vitell- honeycomb bodies
  • Figure 5 Inventive filter unit of two Wandflußfiltern with internal shunts
  • Figure 6 Monolithic filter unit of individual mutually interlocked cuboid filter elements
  • FIG. 1 shows a filter unit (1) which contains two filter units (I) and (II). Each filter unit contains a soot filter (2), (3) and associated external shunts (4) and (5). The shunts are laterally offset from one another.
  • the exhaust gas entering the filter unit is split into a first partial flow (6) flowing through the filter (2) and into a second partial flow (7) flowing through the secondary port (4).
  • the first partial flow is released by the filter according to its filter efficiency of its soot load, while the second partial flow without filtering through the shunt (4) flows.
  • the mixed exhaust gas is split in the second filter unit into a third (8) and fourth (10) partial flow.
  • the third partial flow flows through soot filter (3) and is released according to its filter efficiency of the remaining soot load (11), while the fourth partial flow unfiltered through the shunt (5) flows.
  • FIG. 1 shows the flow conditions with low soot loading of the filter (2) and (3): the main mass flow of the exhaust gas passes through both filters and is freed from soot with high efficiency.
  • FIG. 2 shows the flow conditions with high soot loading of the filters (2) and (3). Due to the high exhaust gas back pressure of the filter loaded with soot, the main mass flow of the exhaust gas is bypassed by the shunts on the filters. The filter effect is low in this case.
  • the further assumption is complete mixing of the two partial flows before entering the filter unit (II ) and also halves division of the mass flows on shunt (5) and filter (3) a soot reduction of the exiting the filter unit exhaust gas by 75%.
  • This value changes constantly during operation of the filtration unit.
  • the ratio of the mass flows of the first to the second partial flow changes dynamically corresponding to the flow resistance formed by the deposition of the soot in the filter (2).
  • the entire exhaust gas flows unfiltered over the two shunts. A complete blockage of the filter unit can not occur.
  • the sizing of the shunts is preferably carried out so that in complete blockage of the filter caused by the shunts exhaust back pressure does not exceed a permissible value.
  • the above-calculated soot reduction can be further improved if it is ensured by fluidic measure that the third partial flow is predominantly formed by the second partial flow and its carbon black is deposited in the second filter unit according to their filter efficiency, while the fourth partial flow predominantly from the first, already Soot-free, partial flow is formed.
  • a measure may be, for example, that the outlet (A) of the first shunt (4) is placed in the filter unit in the flow direction of the exhaust gas behind the inlet (E) of the second shunt (5).
  • This arrangement of outlet and inlet is shown in FIG. This ensures that in normal operation at low filter loads, the exhaust gases purified in the front filter preferably flow through the shunt of the second filter element while the exhaust gases from the front shunt are preferably cleaned in the rear filter.
  • the exhaust back pressure of the two shunts is preferably designed so that just 50% of the exhaust gas flows through the front and rear shunt for a given target loading of the filter unit with soot.
  • the proportion of the exhaust gas flowing through the shunts and thus also the soot passage through the filter unit decreases. If the filter load is greater than the target load, a larger part of the exhaust gas flows through the shunts and leaves the system unfiltered: the soot passage through the filter unit increases. With complete blockage of the filter, the exhaust gas leaves the filter unit unfiltered over both shunts.
  • the overall filtering efficiency of the filtering aggregate depends essentially on the degree of mixing of the individual partial streams in the connecting piece between the inlet (E) of the rear shunt and the outlet (A) of the front shunt. This mixing can be minimized by suitable construction, in the simplest case, for example, by a taper of the connecting piece between the two shunts.
  • the maximum backpressure of the system with fully added filters is determined by the backpressure of the shunts.
  • the dependence of the backpressure of the shunts on the exhaust gas mass flow is determined by the nature of the friction losses in the shunts. Turbulent energy losses lead to a quadratic dependence, while laminar friction losses lead to a linear dependence.
  • the shunts at low filter loading ie low flow rate in shunt a maximum proportion of exhaust gases through the filter elements and have clogged filter elements, ie high flow velocity, the lowest possible back pressure.
  • This goal is best met in the case of a mainly laminar friction loss.
  • a laminar friction energy loss can be achieved, for example, by incorporating flow-through honeycomb bodies (13) and (14) into the shunts.
  • An additional advantage of this arrangement is the ability to catalytically coat these additional flow honeycomb body and thus positively influence the regeneration behavior of the system positively.
  • the filter unit according to the invention is particularly suitable for retrofitting diesel vehicles with a particulate filter.
  • the retrofitted filters must enable trouble-free operation over all operating states of the engine and unlimited operating time even without active regeneration.
  • the filter unit according to the invention meets this requirement. Even with complete blockage of the filter is still a free flow of the exhaust gas through the shunts possible.
  • the filters are always thermally regenerated when the engine is operated under high load with high exhaust gas temperatures.
  • the filters and shunts may be catalytically coated.
  • the filters are advantageously provided with a coating which lowers the soot ignition temperature and the shunts are provided with an oxidation coating.
  • an oxidation catalyst can be arranged in front of the filter, which oxidizes the nitrogen monoxide contained in the exhaust gas to nitrogen dioxide. Nitrogen dioxide is a strong oxidizing agent and can burn the soot deposited on the filters even at relatively low exhaust gas temperatures.
  • the shunt channels are advantageously distributed over the filter so that a uniform heating of the filter is ensured in the regeneration.
  • the total flow resistance must be set via the number of open channels. For a uniform heating of the filter during regeneration, a higher number of open channels is advantageous. Given the overall flow resistance, the number of open channels can be increased as the flow resistance of the individual open channels is increased. For this purpose, either the diameter of the open channels can be made smaller than the diameter of the regular filter channels or partially blocked channels can be used.
  • the shunt channels are arranged geometrically in two successive filters so that the exhaust gas from the shunt channels of the front filter preferably meet on active filter channels in the rear filter and vice versa. Strörungssimulationsmarinen the inventor show that such a selective on-flow of the shunt channels can be realized very easily and efficiently by laterally offset from each other shunt channels. The mixing between the individual partial flows amounts to a few percent.
  • Ceramic Wandflußfilter are usually composed of individual cuboidal elements. A particularly favorable embodiment using such cuboid filter element is shown in FIG 4.
  • the filter units (I) and (II) are located in an exhaust gas cleaning housing (30) and each consist of several cuboid filter elements.
  • Each filter element has some shunt channels, wherein the shunt channels are laterally offset from one another in successive filter elements according to the invention.
  • Each filter unit consists of short (32), (34) and long (31), (33) filter elements, each arranged in a checkered pattern.
  • the short and long filter elements are arranged in the two successive filter units complementary to each other, so that a toothing of the two filter units (I) and (II) is possible.
  • the toothing of the successive filter increases the mechanical stability of the entire filter unit and leads to a monolithic structure. As a result, the geometrically precise relative arrangement of the open channels is ensured in a simple manner.
  • the overall filter unit can also contain some completely continuous filter cuboids without shunt channels.
  • the individual filter elements are formed by correspondingly structured metal foils with integrated filter materials.
  • the shunt channels of each front and rear filter element must be geometrically arranged so that a selective flow according to the invention of the shunt channels is ensured. This can for example be achieved in a simple manner when the two filter elements consist of spirally wound corrugated sheet layers and the shunt channels are arranged in the front and rear filter element in radially offset layers.
  • the system need not necessarily consist of two separate filter monoliths, but the respective front and rear filter elements may for example be designed in radially varying length, so that the front and rear filter elements can be interlocked to increase the stability of the system.
  • the geometric embodiment of the invention is not limited to the relatively simple geometries listed here.
  • the individual filter elements can also be arranged in a very complex form. It is important that according to the invention for a large number of filter channels each have a shunt and that these shunt channels are geometrically connected so that in the case of complete blockage of the filter elements a free flow of the exhaust gas through the shunt channels is possible.
  • Another embodiment of the invention uses catalytically coated filter elements.
  • a different coating can be selected for the front and rear filter elements.
  • the shunt channels can also be catalytically coated.
  • the same or a different coating can be selected as for the filter channels.
  • the flow is largely through the shunt channels. It is therefore helpful to coat the shunt channels with an oxidation catalyst in order to generate as much exotherm as possible during the regeneration. In return, it makes sense to optimize the coating of the filter walls in the direction of a reduced soot ignition temperature.
  • the invention is particularly advantageous when using novel highly porous filter materials. These materials show only a moderate filter efficiency when completely unloaded.
  • a filter system according to the present invention is designed so that for a preselected 'standard load' 50% of the exhaust gas passes through the shunt and 50% through the filter units.
  • the back pressure at standard load is half of the counter pressure occurring at full load.
  • the unloaded filter more than 80% of the exhaust gases go through both filter elements so that here also almost a complete Rußabschei- fertilg is reached.
  • the proportion of the double-filtered gas decreases, but the filter efficiency of the porous filter material increases. In this way, a good degree of separation is achieved over the entire normal operating range.

Abstract

According to the invention, the exhaust gas of a diesel engine is directed via at least two serially arranged filter units (I, II) in order to eliminate soot from the exhaust gas. Each filter unit comprises a filter element with a parallel connection (4) which the exhaust gas can penetrate without being filtered. The parallel connections (4, 5) of two successive filter elements are joined to each other by means of a direct, non-clogging flow path. The parallel connections (4, 5) of the successive filter elements (2, 3) are flowingly disposed relative to each other such that the exhaust gas is largely prevented from penetrating directly from one parallel connection into the parallel connection of the successive filter unit, thus ensuring a great total filter efficiency while the counterpressure of the exhaust gas is comparable to conventional filter systems in spite of the parallel connections (4, 5) in the individual filter units. The parallel connections in the filter units ensure emergency operation at a still admissible counterpressure of the exhaust gas in case active or passive filter regeneration fails.

Description

Verstopfungsfreies Filteraggregat mit hohem Wirkungsgrad Blockage-free filter unit with high efficiency
Beschreibungdescription
Die Erfindung betrifft ein verstopfungsfreies Filteraggregat zur Entfernung von Ruß aus dem Abgas von Dieselmotoren.The invention relates to a blockage-free filter unit for removing soot from the exhaust gas of diesel engines.
Abgasanlagen mit einem Partikelfilter sind bekannt. Ein Problem beim Betrieb von Partikelfiltern ist die Erhöhung des Abgasgegendrucks durch den schon im Filter abgelagerten Ruß. Im ungünstigsten Fall kann der Gegendruck dabei so weit ansteigen, daß es zum Stillstand des Motors kommt. Konventionelle Rußfilter müssen daher von Zeit zu Zeit regeneriert werden, das heißt, der auf ihnen abgelagerte Ruß muß verbrannt werden. Bei einer hohen Rußbeladung kann es durch die Verbrennungswärme des Rußes zu einer Zerstörung des Filters kommen. Durch eine regelmäßige Regeneration wird dies verhindert.Exhaust systems with a particle filter are known. A problem with the operation of particle filters is the increase of the exhaust gas backpressure due to the soot already deposited in the filter. In the worst case, the back pressure can rise so high that it comes to a standstill of the engine. Conventional soot filters must therefore be regenerated from time to time, that is, the soot deposited on them must be burned. With a high soot loading, the combustion heat of the soot can destroy the filter. Regular regeneration prevents this.
Ruß verbrennt erst bei Temperaturen von etwa 600 °C. Die Zündtemperatur des Rußes kann zwar durch die Verwendung von katalytisch aktiven Kraftstoffadditiven oder durch katalytische Beschichtung des Filters auf etwa 400 0C reduziert werden, jedoch wird auch bei katalytischer Aktivierung die Zündtemperatur des Rußes nur in bestimmten Betriebszuständen des Motors erreicht. Um eine Verstopfung des Filters auszuschließen, muß die Rußbeladung des Filters durch die Motorsteuerung aufwendig überwacht und im Bedarfsfall durch eine aktive Erhöhung der Abgastemperatur eine Filter- regeneration eingeleitet werden. Diese aktive Filterregeneration bedingt zwangsläufig einen erhöhten Kraftstoffverbrauch. Die für die Regenerationsmaßnahmen aufzuwendende Kraftstoffmenge wird zusätzlich durch die Unsicherheit bei der Berechnung der Filterbeladung und die dadurch notwendigen Sicherheitsreserven erhöht.Soot burns only at temperatures of about 600 ° C. Although the ignition temperature of the soot can be reduced by the use of catalytically active fuel additives or by catalytic coating of the filter to about 400 0 C, but even with catalytic activation, the ignition temperature of the soot is achieved only in certain operating conditions of the engine. To exclude a blockage of the filter, the soot load of the filter must be monitored consuming by the engine control and, if necessary, a filter regeneration can be initiated by an active increase in the exhaust gas temperature. This active filter regeneration inevitably requires increased fuel consumption. The amount of fuel to be expended for the regeneration measures is additionally increased by the uncertainty in the calculation of the filter load and the necessary safety reserves.
Die Abgasanlagen älterer Dieselfahrzeuge werden häufig nachträglich mit einem Parti- kelfilter ausgerüstet. Da diese Fahrzeuge nicht in der Lage sind, das nachgerüstete Filter aktiv zu regenerieren, verbleibt nur eine passive Regeneration bei Betriebsbedingungen mit hoher Last und hohen Abgastemperaturen. Da diese Betriebsbedingungen nur vonThe exhaust systems of older diesel vehicles are often retrofitted with a particulate filter. Since these vehicles are unable to actively regenerate the retrofitted filter, only passive regeneration remains under high load, high exhaust gas temperature operating conditions. Since these operating conditions only from
Fall zu Fall auftreten und zum Teil auch über längere Zeiten völlig ausbleiben können, muß das Nachrüstfilter einen verstopfungsfreien Betrieb auch bei lange Zeit ausblei- bender passiver Regeneration gewährleisten.Case after case occur and partly even over longer periods can completely fail, the retrofit filter must ensure a clog-free operation even with long time passive regeneration passive.
Die Gefahr einer Filterverstopfung kann durch ein sogenanntes offenes Filtersystem vermieden werden. Hier wird neben dem Strömungsweg durch das Filtermedium ein weiterer Strömungsweg zur Verfügung gestellt (Nebenschluß), der das Filtermedium umgeht. Mit zunehmender Rußbeladung des Filters nimmt der Gegendruck des Filters im Vergleich zum Nebenschluß zu; ein größerer Anteil der Gesamtströmung verlagert sich in den Nebenschluß und der weitere Anstieg der Filterbeladung wird verlangsamt. Auf diese Weise wird eine zu hohe Beladung des Filters und damit eine Zerstörung des Filters durch zu hohe Temperaturen bei der Regeneration verhindert. Selbst bei vollständiger Verstopfung des Filtermaterials kann das Abgas noch durch den Nebenschluß strömen, eine Verstopfung des Gesamtsystems ist nicht möglich.The risk of filter clogging can be avoided by a so-called open filter system. Here is next to the flow path through the filter medium another flow path provided (shunt), which bypasses the filter medium. With increasing soot loading of the filter, the back pressure of the filter increases in comparison to the shunt; a greater portion of the total flow shifts to the shunt and the further increase in filter loading is slowed. In this way, excessive loading of the filter and thus destruction of the filter due to excessive temperatures during regeneration is prevented. Even with complete blockage of the filter material, the exhaust gas can still flow through the shunt, a blockage of the entire system is not possible.
Aus der Literatur ist eine große Anzahl unterschiedlicher Ausfuhrungsformen von offenen Filtersystemen bekannt. Ein Beispiel eines offenen Filters gibt die deutscheFrom the literature, a large number of different embodiments of open filter systems is known. An example of an open filter is the German one
Offenlegungsschrift DE 100 44 893 Al. Diese Schrift beschreibt ein Partikelfilter zurLaid-open specification DE 100 44 893 A1. This document describes a particle filter for
Abgasreinigung einer Dieselbrennkraftmaschine mit einem im Innern des Filters inExhaust gas purification of a diesel internal combustion engine with an inside of the filter in
Längsrichtung angeordneten Nebenschluß. Dabei ist die Öffnung des Nebenschlusses an einem Ort der vorderen Stirnfläche des Partikelfilters angeordnet, der nicht oder nur gering vom partikelbehafteten Abgas angeströmt wird. Eine ähnliche Anordnung wird auch in der europäischen Offenlegungsschrift EP 0 879 938 A2 beschrieben.Longitudinally arranged shunt. In this case, the opening of the shunt is arranged at a location of the front end face of the particle filter, which is not or only slightly flowed through by the particle-laden exhaust gas. A similar arrangement is also described in European published patent application EP 0 879 938 A2.
Eine weiteres Beispiel eines offenen Filtersystems gibt die europäische Offenlegungsschrift EP 1 219 794 Al. Sie beschreibt ein Wandflußfilter mit wechselseitig verschlossenen Strömungskanälen. Zur Sicherstellung eines verstopfungsfreien Betriebs sind einige der Verschlüsse teilweise geöffnet, so daß die betroffenen Strömungskanäle einen freien Durchtritt des Abgases erlauben. Die Anwendung einzelner geöffneter Kanäle als Nebenschluß in einem offenen Filtersystem wird ebenfalls im amerikanischen Patent US 4,464,185 beschrieben.Another example of an open filter system is the European patent application EP 1 219 794 Al. It describes a Wandflußfilter with mutually closed flow channels. To ensure clog-free operation, some of the shutters are partially open so that the affected flow channels allow free passage of the exhaust gas. The use of individual open channels as a shunt in an open filter system is also described in US Pat. No. 4,464,185.
Der Hauptnachteil der zuvor beschriebenen offenen Filtersysteme liegt in der Tatsache, daß bei diesen Systemen auch im Normalbetrieb Abgas durch den Nebenschluß ungefiltert in die Umgebung entweicht. Mit diesen Filtersystemen kann daher häufig nicht die gewünschte Filterwirkung gewährleistet werden.The main disadvantage of the above-described open filter systems lies in the fact that in these systems exhaust gas escapes unfiltered into the environment even during normal operation. With these filter systems, therefore, often the desired filtering effect can not be guaranteed.
Dementsprechend besteht weiterhin der Bedarf für ein Filtersystem, welches einen verstopfungsfreien Betrieb ohne aktive Regeneration und mit gutem Filterwirkungsgrad ermöglicht.Accordingly, there remains a need for a filtration system that allows for clog-free operation without active regeneration and with good filtration efficiency.
Die Lösung dieses Problems erfolgt erfindungsgemäß durch das Hintereinanderschalten mehrerer Filterelemente mit geeignet angeordneten Nebenschlüssen für das Abgas, wobei die Nebenschlüsse im Falle der Verstopfung der Filter durch Ruß einen verstopfungsfreien Strömungsweg für das Abgas bilden.The solution of this problem is inventively by the series connection of several filter elements with suitably arranged shunts for the exhaust gas, wherein the shunts form a blockage-free flow path for the exhaust gas in the event of blockage of the filters by soot.
Die Verwendung mehrerer hintereinandergeschalteter Filterelemente auch in Verbindung mit Nebenschlüssen für die einzelnen Filterelemente ist aus der Patentliteratur bekannt. So wird in der deutschen Offenlegungsschrift DE 198 55 093 Al ein System bestehend aus zwei hintereinander angeordneten Filterelementen beschrieben. Ein Teilstrom wird in einem Nebenschluß an dem vorderen Filterelement vorbeigeführt und im hinteren Element gereinigt. Ein weiterer Teilstrom wird im vorderen Element gereinigt und in einem Nebenschluß an dem hinteren Element vorbeigeführt. Sehr ähnliche Systeme werden auch in den amerikanischen Patenten US 6,464,744 B2 und US 4,625,511 beschrieben.The use of a plurality of cascaded filter elements also in connection with shunts for the individual filter elements is known from the patent literature. Thus, German Patent Application DE 198 55 093 A1 describes a system consisting of two filter elements arranged one behind the other. A partial flow is passed in a shunt on the front filter element and cleaned in the rear element. Another partial stream is cleaned in the front element and passed in a shunt on the rear element. Very similar systems are also described in US Pat. Nos. 6,464,744 B2 and 4,625,511.
Im amerikanischen Patent US 4,625,511 wird ein System mit zwei hintereinander angeordneten Filtern offenbart, wobei nur das erste Filter mit einem Nebenschluß versehen ist. Ein ähnliches System ist auch in der deutschen Offenlegungsschrift DE 101 51 698 Al beschrieben. Der Vorteil dieser Systeme besteht darin, daß eine gleichmäßigere Beladung der beiden Filter mit Ruß erreicht wird.US Pat. No. 4,625,511 discloses a system with two filters arranged one behind the other, with only the first filter being shunted. A similar system is also described in German Offenlegungsschrift DE 101 51 698 A1. The advantage of these systems is that a more uniform loading of the two filters is achieved with soot.
Die zuvor beschriebenen Konstruktionen aus mehreren hintereinandergeschalteten Filterelementen mit Nebenschlüssen für ein oder mehrere Filterelemente sind geschlossene Filtersysteme, das heißt, sie erfüllen nicht die Anforderung nach einem verstop- fungsfreien Filtersystem. Vielmehr werden hier mehrere Filter in Reihe geschaltet. Die Verstopfung eines Filters führt zur Verstopfung des gesamten Systems.The previously described constructions of multiple cascaded filter elements with shunts for one or more filter elements are closed filter systems, that is, they do not meet the requirement for a clog-free filter system. Rather, several filters are connected in series here. The clogging of a filter leads to blockage of the entire system.
Die vorliegende Erfindung offenbart ein offenes, und damit verstopfungsfreies, Filteraggregat mit gutem Filterwirkungsgrad für die Entfernung von Ruß aus dem Abgas von Dieselmotoren. Das Filteraggregat besteht aus wenigsten zwei in einem Abstand hinter- einandergeschalteten Filtereinheiten, die nacheinander vom Abgas durchflössen werden. Das Filteraggregat ist dadurch gekennzeichnet, daß jede Filtereinheit einen oder mehrere Nebenschlüsse aufweist, die in zwei aufeinanderfolgenden Filtereinheiten seitlich gegeneinander versetzt sind und wobei zwischen den Nebenschlüssen der aufeinanderfolgenden Filtereinheiten ein verstopfungsfreier Strömungsweg besteht.The present invention discloses an open, and thus blockage-free, filtration unit with good filter efficiency for the removal of soot from the exhaust of diesel engines. The filter unit consists of at least two filter units which are interlinked at a distance and are flowed through in succession by the exhaust gas. The filter unit is characterized in that each filter unit has one or more shunts, which are laterally offset from each other in two successive filter units and wherein there is a blockage-free flow path between the shunts of the successive filter units.
Jede Filtereinheit enthält also ein Partikelfilter und einen oder mehrere Nebenschlüsse, durch die ein Teil des Abgases ungefiltert die zugeordnete Filtereinheit passieren kann. Die Nebenschlüsse können sowohl im Innern des jeweiligen Partikelfilters oder extern angeordnet sein. Erfindungsgemäß besteht zwischen den Nebenschlüssen zweier aufeinanderfolgenden Filtereinheiten ein verstopfungsfreier Strömungsweg, so daß auch für den Fall einer vollständigen Verstopfung der Filter das Abgas noch ungehindert über die Nebenschlüsse durch das Filteraggregat fließen kann. Die Nebenschlüsse zweier aufeinander- folgender Filtereinheiten sind seitlich gegeneinander versetzt, so daß die Abgasanteile, die das vordere Partikelfilter durchströmt haben und gereinigt wurden, bevorzugt durch die Nebenschlüsse der nachfolgenden Filtereinheit strömen, während die Abgasanteile aus den Nebenschlüssen der vorderen Filtereinheit bevorzugt durch das hintere Partikelfilter strömen. Dadurch ist trotz der Nebenschlüsse in den einzelnen Filtereinheiten ein hoher Gesamtfilterwirkungsgrad bei vergleichbarem Abgasgegendruck wie bei konventionellen Filteranlagen gewährleistet.Each filter unit thus contains a particle filter and one or more shunts through which a portion of the exhaust gas can pass unfiltered through the associated filter unit. The shunts can be arranged both inside the respective particle filter or externally. According to the invention there is a blockage-free flow path between the shunts of two successive filter units, so that even in the case of a complete blockage of the filter, the exhaust gas can flow unhindered through the shunts through the filter unit. The shunts of two successive filter units are laterally offset from each other, so that the exhaust gas fractions, which have flowed through the front particulate filter and cleaned, preferably flow through the shunts of the subsequent filter unit, while the exhaust gas components from the shunts of the front filter unit preferably through the rear particulate filter stream. As a result, despite the shunts in the individual filter units, a high overall filter efficiency at a comparable exhaust back pressure as in conventional filter systems is ensured.
Entscheidend für die Funktionsfähigkeit dieser Anordnung ist, daß eine direkte, verstopfungsfreie Strömungsverbindung zwischen den Nebenschlüssen der hintereinander angeordneten Filtereinheiten möglich ist. Nur durch diese direkte Strömungsverbindung zwischen den Nebenschlüssen zweier aufeinanderfolgender Filtereinheiten ist im Falle einer vollständigen Verstopfung der Partikelfilter stets noch eine freier Strömungsweg für die Abgase durch die Nebenschlüsse gewährleistet. Die Nebenschlüsse in den Filtereinheiten stellen also einen Notbetrieb mit noch zulässigem Abgasgegendruck sicher, wenn die Filterregeneration, sei es aktiv oder passiv, einmal ausfallen sollte.Crucial to the operability of this arrangement is that a direct, clog-free flow connection between the shunts of the filter units arranged one behind the other is possible. Only through this direct flow connection between the shunts of two successive filter units is a free flow path for the exhaust gases through the shunts always ensured in the case of complete blockage of the particulate filter. The shunts in the filter units thus ensure an emergency operation with still permissible exhaust back pressure, if the filter regeneration, be it active or passive, should fail once.
Die Erfindung wird an Hand der Figuren 1 bis 3 näher erläutert. Es zeigenThe invention will be explained in more detail with reference to Figures 1 to 3. Show it
Figur 1: Erfindungsgemäßes Filteraggregat mit externen Nebenschlüssen: Strömungsverhältnisse bei Filtern mit geringer RußbeladungFigure 1: Inventive filter unit with external shunts: flow conditions in filters with low soot loading
Figur 2: Erfindungsgemäßes Filteraggregat mit externen Nebenschlüssen: Strömungsverhältnisse bei Filtern mit hoher RußbeladungFigure 2: Inventive filter unit with external shunts: flow conditions in filters with high soot loading
Figur 3: Filteraggregat von Figur 1 mit Auslaß A des ersten Nebenschlusses in Strömungsrichtung des Abgases hinter Einlaß E des zweiten NebenschlussesFigure 3: Filter unit of Figure 1 with outlet A of the first shunt in the flow direction of the exhaust gas behind the inlet E of the second shunt
Figur 4: Filteraggregat nach Figur 1 mit in den Nebenschlüssen angeordneten Durchfluß- WabenkörpernFigure 4: filter unit of Figure 1 with arranged in the shunts Durchfluß- honeycomb bodies
Figur 5: Erfindungsgemäßes Filteraggregat aus zwei Wandflußfiltern mit internen Nebenschlüssen Figur 6: Monolithisches Filteraggregat aus einzelnen miteinander verzahnten quaderförmigen FilterelementenFigure 5: Inventive filter unit of two Wandflußfiltern with internal shunts Figure 6: Monolithic filter unit of individual mutually interlocked cuboid filter elements
Das der Erfindung zugrundeliegende Funktionsprinzip kann gut anhand der in Figur 1 dargestellten Ausfuhrungsform verdeutlicht werden. Figur 1 zeigt ein Filteraggregat (1), welches zwei Filtereinheiten (I) und (II) enthält. Jede Filtereinheit enthält ein Rußfilter (2), (3) und zugeordnete externe Nebenschlüsse (4) und (5). Die Nebenschlüsse sind seitlich zueinander versetzt angeordnet.The principle underlying the invention can be clearly illustrated by the embodiment shown in Figure 1. FIG. 1 shows a filter unit (1) which contains two filter units (I) and (II). Each filter unit contains a soot filter (2), (3) and associated external shunts (4) and (5). The shunts are laterally offset from one another.
Durch diese Anordnung wird das in das Filteraggregat eintretende Abgas in einen ersten durch das Filter (2) fließenden Teilstrom (6) und in einen zweiten durch den Ne- benschluß (4) fließenden Teilstrom (7) aufgespalten. Der erste Teilstrom wird durch das Filter entsprechend seinem Filterwirkungsgrad von seiner Rußfracht befreit, während der zweite Teilstrom ohne Filterung durch den Nebenschluß (4) fließt. Nach Durchströmen der ersten Filtereinheit (I) erfolgt eine gewisse Durchmischung des ersten mit dem zweiten Teilstrom des Abgases. Das durchmischte Abgas wird in der zweiten Filtereinheit in einen dritten (8) und vierten (10) Teilstrom aufgespalten. Der dritte Teilstrom fließt durch Rußfilter (3) und wird entsprechend seinem Filterwirkungsgrad von der verbliebenen Rußfracht befreit (11), während der vierte Teilstrom ungefiltert durch den Nebenschluß (5) fließt.By this arrangement, the exhaust gas entering the filter unit is split into a first partial flow (6) flowing through the filter (2) and into a second partial flow (7) flowing through the secondary port (4). The first partial flow is released by the filter according to its filter efficiency of its soot load, while the second partial flow without filtering through the shunt (4) flows. After flowing through the first filter unit (I), a certain mixing of the first and the second partial flow of the exhaust gas takes place. The mixed exhaust gas is split in the second filter unit into a third (8) and fourth (10) partial flow. The third partial flow flows through soot filter (3) and is released according to its filter efficiency of the remaining soot load (11), while the fourth partial flow unfiltered through the shunt (5) flows.
Figur 1 zeigt die Strömungsverhältnisse bei geringer Rußbeladung der Filter (2) und (3): der Hauptmassenstrom des Abgases geht durch beide Filter und wird mit hoher Effizienz vom Ruß befreit. Figur 2 zeigt dagegen die Strömungsverhältnisse bei hoher Rußbeladung der Filter (2) und (3). Aufgrund des hohen Abgasgegendrucks der mit Ruß beladenen Filter wird der Hauptmassenstrom des Abgases durch die Nebenschlüsse an den Filtern vorbeigeleitet. Die Filterwirkung ist in diesem Fall gering.Figure 1 shows the flow conditions with low soot loading of the filter (2) and (3): the main mass flow of the exhaust gas passes through both filters and is freed from soot with high efficiency. In contrast, FIG. 2 shows the flow conditions with high soot loading of the filters (2) and (3). Due to the high exhaust gas back pressure of the filter loaded with soot, the main mass flow of the exhaust gas is bypassed by the shunts on the filters. The filter effect is low in this case.
Wird beispielhaft angenommen, daß erster und zweiter Teilstrom jeweils 50 % des gesamten Abgasmassenstromes ausmachen und im Filter (2) der erste Teilstrom vollständig vom Ruß befreit wird, so ergibt sich unter der weiteren Annahme einer vollständigen Durchmischung beider Teilströme vor Eintritt in die Filtereinheit (II) und ebenfalls hälftiger Aufteilung der Massenströme auf Nebenschluß (5) und Filter (3) eine Rußverminderung des aus dem Filteraggregat austretenden Abgases um 75 %.If it is assumed by way of example that the first and second partial flow each make up 50% of the total exhaust gas mass flow and the first partial flow is completely freed of soot in the filter (2), the further assumption is complete mixing of the two partial flows before entering the filter unit (II ) and also halves division of the mass flows on shunt (5) and filter (3) a soot reduction of the exiting the filter unit exhaust gas by 75%.
Dieser Wert ändert sich während des Betriebs des Filteraggregats ständig. Je mehr Ruß sich in den Filtern ablagert, um so mehr verlagert sich die Abgasströmung auf die Nebenschlüsse. Das Verhältnis der Massenströme des ersten zum zweiten Teilstrom ändert sich dynamisch entsprechend des sich durch die Ablagerung des Rußes in Filter (2) ausbildenden Strömungs Widerstandes. Entsprechendes gilt für das Verhältnis der Massenströme des dritten zum vierten Teilstrom. In dem Extremfall der Verstopfung beider Filter fließt das gesamte Abgas ungefiltert über die beiden Nebenschlüsse. Eine voll- ständige Verstopfung des Filteraggregats kann nicht eintreten. Die Dimensionierung der Nebenschlüsse wird vorzugsweise so vorgenommen, daß bei vollständiger Verstopfung der Filter der durch die Nebenschlüsse verursachte Abgasgegendruck einen zulässigen Wert nicht überschreitet.This value changes constantly during operation of the filtration unit. The more soot deposits in the filters, the more the flow of exhaust gas shifts to the shunts. The ratio of the mass flows of the first to the second partial flow changes dynamically corresponding to the flow resistance formed by the deposition of the soot in the filter (2). The same applies to the ratio of the mass flows of the third to the fourth partial flow. In the extreme case of the blockage of both filters, the entire exhaust gas flows unfiltered over the two shunts. A complete blockage of the filter unit can not occur. The sizing of the shunts is preferably carried out so that in complete blockage of the filter caused by the shunts exhaust back pressure does not exceed a permissible value.
Die oben beispielhaft berechnete Rußverminderung kann weiter verbessert werden, wenn durch strömungstechnische Maßnahme sichergestellt wird, daß der dritte Teilstrom überwiegend durch den zweiten Teilstrom gebildet wird und seine Rußfracht in der zweiten Filtereinheit entsprechend ihrem Filterwirkungsgrad abgelagert wird, während der vierte Teilstrom überwiegend vom ersten, schon von Ruß befreitem, Teilstrom gebildet wird. Eine solche Maßnahme kann zum Beispiel darin bestehen, daß der Aus- laß (A) des ersten Nebenschlusses (4) in das Filteraggregat in Strömungsrichtung des Abgases hinter den Einlaß (E) des zweiten Nebenschlusses (5) gelegt wird. Diese Anordnung von Aus- und Einlaß ist in Figur 3 gezeigt. Hierdurch wird erreicht, daß im Normalbetrieb bei niedrigen Filterbeladungen die im vorderen Filter gereinigten Abgase bevorzugt durch den Nebenschluß des zweiten Filterelements abfließen während die Abgase aus dem vorderen Nebenschluß bevorzugt im hinteren Filter gereinigt werden.The above-calculated soot reduction can be further improved if it is ensured by fluidic measure that the third partial flow is predominantly formed by the second partial flow and its carbon black is deposited in the second filter unit according to their filter efficiency, while the fourth partial flow predominantly from the first, already Soot-free, partial flow is formed. Such a measure may be, for example, that the outlet (A) of the first shunt (4) is placed in the filter unit in the flow direction of the exhaust gas behind the inlet (E) of the second shunt (5). This arrangement of outlet and inlet is shown in FIG. This ensures that in normal operation at low filter loads, the exhaust gases purified in the front filter preferably flow through the shunt of the second filter element while the exhaust gases from the front shunt are preferably cleaned in the rear filter.
Der Abgasgegendruck der beiden Nebenschlüsse wird bevorzugt so ausgelegt, daß für eine vorgegebene Soll-Beladung des Filteraggregates mit Ruß gerade 50 % des Abgases durch den vorderen und hinteren Nebenschluß fließt. Bei einer niedrigeren Filterbeladung vermindert sich der durch die Nebenschlüsse fließende Anteil des Abgases und somit auch der Rußdurchtritt durch das Filteraggregat. Ist die Filterbeladung größer als die Soll-Beladung, so fließt ein größerer Teil des Abgases durch die Nebenschlüsse und verläßt das System ungefiltert: der Rußdurchtritt durch das Filteraggregat vergrößert sich. Bei vollständiger Verstopfung der Filter verläßt das Abgas das Filteraggregat über beide Nebenschlüsse ungefiltert.The exhaust back pressure of the two shunts is preferably designed so that just 50% of the exhaust gas flows through the front and rear shunt for a given target loading of the filter unit with soot. At a lower filter load, the proportion of the exhaust gas flowing through the shunts and thus also the soot passage through the filter unit decreases. If the filter load is greater than the target load, a larger part of the exhaust gas flows through the shunts and leaves the system unfiltered: the soot passage through the filter unit increases. With complete blockage of the filter, the exhaust gas leaves the filter unit unfiltered over both shunts.
Der Gesamt-Filterwirkungsgrad des Filteraggregates hängt wesentlich von dem Grad der Vermischung der einzelnen Teilströme im Verbindungsstück zwischen dem Einlaß (E) des hinteren Nebenschlusses und dem Auslaß (A) des vorderen Nebenschlusses ab. Diese Vermischung kann durch geeignete Konstruktion minimiert werden, im einfachsten Fall zum Beispiel durch eine Verjüngung des Verbindungsstückes zwischen den beiden Nebenschlüssen. Der maximale Gegendruck des Systems bei vollständig zugesetzten Filtern wird durch den Gegendruck der Nebenschlüsse bestimmt. Die Abhängigkeit des Gegendrucks der Nebenschlüsse vom Abgasmassenstrom wird durch die Art der Reibungsverluste in den Nebenschlüssen bestimmt. Turbulente Energieverluste fuhren zu einer quadratischen Abhängigkeit, während laminare Reibungsverluste zu einer linearen Abhängigkeit fuhren. Vorteilhaft im Sinne der Erfindung ist es, wenn die Nebenschlüsse bei niedriger Filterbeladung, also niedriger Strömungsgeschwindigkeit im Nebenschluß einen möglichst großen Anteil der Abgase durch die Filterelemente lenken und bei verstopften Filterelementen, also hoher Strömungsgeschwindigkeit, einen möglichst niedrigen Gegendruck aufweisen. Diese Zielvorgabe wird am besten im Fall eines hauptsächlich laminaren Reibungsverlusts erfüllt. Ein laminarer Reibungsenergieverlust kann zum Beispiel durch den Einbau von Durchfluß- Wabenkörper (13) und (14) in die Nebenschlüsse erreicht werden. Ein zusätzlicher Vorteil dieser Anordnung besteht in der Möglichkeit, diese zusätzlichen Durchfluß- Wabenkörper katalytisch zu beschichten und damit das Regenerationsverhalten des Systems gezielt positiv zu beeinflussen.The overall filtering efficiency of the filtering aggregate depends essentially on the degree of mixing of the individual partial streams in the connecting piece between the inlet (E) of the rear shunt and the outlet (A) of the front shunt. This mixing can be minimized by suitable construction, in the simplest case, for example, by a taper of the connecting piece between the two shunts. The maximum backpressure of the system with fully added filters is determined by the backpressure of the shunts. The dependence of the backpressure of the shunts on the exhaust gas mass flow is determined by the nature of the friction losses in the shunts. Turbulent energy losses lead to a quadratic dependence, while laminar friction losses lead to a linear dependence. Advantageous in the context of the invention, it is when the shunts at low filter loading, ie low flow rate in shunt a maximum proportion of exhaust gases through the filter elements and have clogged filter elements, ie high flow velocity, the lowest possible back pressure. This goal is best met in the case of a mainly laminar friction loss. A laminar friction energy loss can be achieved, for example, by incorporating flow-through honeycomb bodies (13) and (14) into the shunts. An additional advantage of this arrangement is the ability to catalytically coat these additional flow honeycomb body and thus positively influence the regeneration behavior of the system positively.
Das erfindungsgemäße Filteraggregat eignet sich besonders zur Nachrüstung von Dieselfahrzeugen mit einem Partikelfilter. Die nachgerüsteten Filter müssen auch ohne aktive Regeneration einen störungsfreien Betrieb über alle Betriebszustände des Motors und unbegrenzte Betriebsdauer ermöglichen. Das erfindungsgemäße Filteraggregat wird dieser Anforderung gerecht. Selbst bei völliger Verstopfung der Filter ist immer noch eine freie Strömung des Abgases durch die Nebenschlüsse möglich.The filter unit according to the invention is particularly suitable for retrofitting diesel vehicles with a particulate filter. The retrofitted filters must enable trouble-free operation over all operating states of the engine and unlimited operating time even without active regeneration. The filter unit according to the invention meets this requirement. Even with complete blockage of the filter is still a free flow of the exhaust gas through the shunts possible.
Die Filter werden immer dann thermisch regeneriert, wenn der Motor unter hoher Belastung mit hohen Abgastemperaturen betrieben wird. Zur Unterstützung der Regeneration können die Filter und die Nebenschlüsse katalytisch beschichtet sein. Dabei werden die Filter vorteilhafterweise mit einer die Rußzündtemperatur absenkenden Beschich- tung und die Nebenschlüsse mit einer Oxidationsbeschichtung versehen. Zusätzlich kann vor das Filter eine Oxidationskatalysator angeordnet werden, der das im Abgas enthaltene Stickstoffmonoxid zu Stickstoffdioxid oxidiert. Stickstoffdioxid ist ein starkes Oxidationsmittel und kann den auf den Filtern abgelagerten Ruß auch schon bei relativ geringen Abgastemperaturen verbrennen.The filters are always thermally regenerated when the engine is operated under high load with high exhaust gas temperatures. To aid regeneration, the filters and shunts may be catalytically coated. The filters are advantageously provided with a coating which lowers the soot ignition temperature and the shunts are provided with an oxidation coating. In addition, an oxidation catalyst can be arranged in front of the filter, which oxidizes the nitrogen monoxide contained in the exhaust gas to nitrogen dioxide. Nitrogen dioxide is a strong oxidizing agent and can burn the soot deposited on the filters even at relatively low exhaust gas temperatures.
Die zuvor geschilderte einfache Ausführungsform der Erfindung mit außen an den Filtern vorbeigeführten Nebenschlüssen besitzt den Nachteil, daß im Falle einer einmal eingetretenen Verstopfung der Filter der Abgasstrom vollständig durch die Nebenschlüsse erfolgt und die Filterelemente bei einer Regeneration deshalb sehr langsam von der Frontseite her durch Wärmeleitung aufgeheizt werden müssen. Vorteilhafter ist eine Integration der Nebenschlüsse direkt in die Filter, zum Beispiel im Fall eines Wandflußfilters durch einige offene Kanäle. Eine solche Ausführungsform der Erfindung zeigt Figur 3. Bezugsziffer (20) bezeichnet ein Abgasreinigungsgehäuse, in dem zwei Wandflußfilter (21) und (22) hintereinander angeordnet sind. In beiden Filtern sind einige Strömungskanäle als Durchflußkanäle, das heißt als Nebenschluß-Kanäle, ausgebildet.The previously described simple embodiment of the invention with externally routed past the filters shunts has the disadvantage that in the case of a once occurred clogging of the filter, the exhaust flow is completely through the shunts and the filter elements in a regeneration therefore heated very slowly from the front side by heat conduction Need to become. More advantageous is a Integration of the shunts directly into the filters, for example in the case of a Wandflußfilters through some open channels. Such an embodiment of the invention is shown in Fig. 3. Numeral (20) denotes an exhaust gas purifying case in which two wall flow filters (21) and (22) are arranged one behind the other. In both filters, some flow channels are formed as flow channels, that is, as shunt channels.
Die Nebenschluß-Kanäle werden zweckmäßigerweise so über die Filter verteilt, daß ein gleichmäßiges Aufheizen der Filter bei der Regeneration gewährleistet ist. Der Gesamt- Strömungswiderstand muß dabei über die Anzahl der offenen Kanäle eingestellt wer- den. Für ein gleichmäßiges Aufheizen des Filters bei der Regeneration ist eine höhere Zahl von offenen Kanälen vorteilhaft. Bei gegebenem Gesamt-Strömungswiderstand kann die Anzahl der offenen Kanäle erhöht werden, wenn der Strömungswiderstand der einzelnen offenen Kanäle heraufgesetzt wird. Zu diesem Zweck kann entweder der Durchmesser der offenen Kanäle kleiner gewählt werden als der Durchmesser der regu- lären Filterkanäle oder es können teilweise verstopfte Kanäle verwendet werden.The shunt channels are advantageously distributed over the filter so that a uniform heating of the filter is ensured in the regeneration. The total flow resistance must be set via the number of open channels. For a uniform heating of the filter during regeneration, a higher number of open channels is advantageous. Given the overall flow resistance, the number of open channels can be increased as the flow resistance of the individual open channels is increased. For this purpose, either the diameter of the open channels can be made smaller than the diameter of the regular filter channels or partially blocked channels can be used.
Erfindungsgemäß sind die Nebenschluß-Kanäle in zwei aufeinander folgenden Filtern geometrisch so angeordnet, daß das Abgas aus den Nebenschluß-Kanälen des vorderen Filters bevorzugt auf aktive Filterkanäle im hinteren Filter treffen und umgekehrt. Strörnungssimulationsrechnungen der Erfinder zeigen, daß eine solche selektive An- Strömung der Nebenschluß-Kanäle durch seitlich gegeneinander versetzt liegende Nebenschluß-Kanäle sehr einfach und effizient realisiert werden kann. Die Vermischung zwischen den einzelnen Teilströmungen beträgt dabei einige wenige Prozent.According to the shunt channels are arranged geometrically in two successive filters so that the exhaust gas from the shunt channels of the front filter preferably meet on active filter channels in the rear filter and vice versa. Strörungssimulationsrechnungen the inventor show that such a selective on-flow of the shunt channels can be realized very easily and efficiently by laterally offset from each other shunt channels. The mixing between the individual partial flows amounts to a few percent.
Keramische Wandflußfilter werden in der Regel aus einzelnen quaderförmigen Elementen zusammengesetzt. Eine besonders günstige Ausführungsform unter Verwendung solcher quaderförmiger Filterelement zeigt Figur 4. Die Filtereinheiten (I) und (II) befinden sich in einem Abgasreinigungsgehäuse (30) und bestehen jeweils aus mehreren quaderförmigen Filterelementen. Jedes Filterelement weist einige Nebenschluß- Kanäle auf, wobei die Nebenschluß-Kanäle in aufeinanderfolgenden Filterelementen erfϊndungsgemäß seitlich gegeneinander versetzt sind.Ceramic Wandflußfilter are usually composed of individual cuboidal elements. A particularly favorable embodiment using such cuboid filter element is shown in FIG 4. The filter units (I) and (II) are located in an exhaust gas cleaning housing (30) and each consist of several cuboid filter elements. Each filter element has some shunt channels, wherein the shunt channels are laterally offset from one another in successive filter elements according to the invention.
Jede Filtereinheit besteht aus kurzen (32), (34) und langen (31), (33) Filterelementen, die jeweils in einem schachbrettartigen Muster angeordnet sind. Die kurzen und langen Filterelemente sind dabei in den beiden aufeinanderfolgenden Filtereinheiten komplementär zueinander angeordnet, so daß eine Verzahnung der beiden Filtereinheiten (I) und (II) möglich ist. Die Verzahnung der hintereinanderliegenden Filter erhöht die mechanischen Stabilität des gesamten Filteraggregats und führt zu einem monolithischen Aufbau. Hierdurch ist auch die geometrisch präzise relative Anordnung der offenen Kanäle auf einfache Weise gewährleistet. Das Gesamt-Filteraggregat kann dabei auch einige vollständig durchgehende Filter-Quader ohne Nebenschluß-Kanäle enthal- ten.Each filter unit consists of short (32), (34) and long (31), (33) filter elements, each arranged in a checkered pattern. The short and long filter elements are arranged in the two successive filter units complementary to each other, so that a toothing of the two filter units (I) and (II) is possible. The toothing of the successive filter increases the mechanical stability of the entire filter unit and leads to a monolithic structure. As a result, the geometrically precise relative arrangement of the open channels is ensured in a simple manner. The overall filter unit can also contain some completely continuous filter cuboids without shunt channels.
In einer weiteren Ausführungsform der Erfindung werden die einzelnen Filterelemente durch entsprechend strukturierte Metallfolien mit integrierten Filtermaterialien gebildet. Auch hier müssen die Nebenschluß-Kanäle des jeweils vorderen und hinteren Filterelements geometrisch so angeordnet werden, daß eine erfindungsgemäße selektive Anströmung der Nebenschluß-Kanäle sichergestellt wird. Dies kann zum Beispiel auf einfache Weise erreicht werden, wenn die beiden Filterelemente aus spiralförmig aufgewickelten Wellblech-Lagen bestehen und die Nebenschluß-Kanäle im vorderen und hinteren Filterelement in radial versetzt liegenden Lagen angeordnet werden. Auch hier muß das System nicht zwangsläufig aus zwei getrennten Filter-Monolithen bestehen, sondern die jeweils vorderen und hinteren Filterelemente können zum Beispiel in radial variierender Länge ausgeführt sein, so daß die vorderen und hinteren Filterelemente zur Erhöhung der Stabilität des Systems miteinander verzahnt werden können.In a further embodiment of the invention, the individual filter elements are formed by correspondingly structured metal foils with integrated filter materials. Again, the shunt channels of each front and rear filter element must be geometrically arranged so that a selective flow according to the invention of the shunt channels is ensured. This can for example be achieved in a simple manner when the two filter elements consist of spirally wound corrugated sheet layers and the shunt channels are arranged in the front and rear filter element in radially offset layers. Again, the system need not necessarily consist of two separate filter monoliths, but the respective front and rear filter elements may for example be designed in radially varying length, so that the front and rear filter elements can be interlocked to increase the stability of the system.
Die geometrische Ausführung der Erfindung ist nicht auf die hier aufgeführten relative einfachen Geometrien beschränkt. Insbesondere bei der Ausführung als Metallfilter können die einzelnen Filterelemente auch in sehr komplexer Form angeordnet werden. Wichtig ist, daß erfindungsgemäß für eine große Anzahl der Filterkanäle jeweils ein Nebenschluß besteht und daß diese Nebenschluß-Kanäle geometrisch so verbunden sind, daß im Falle einer vollständigen Verstopfung der Filterelemente eine freie Durchströmung des Abgases durch die Nebenschluß-Kanäle möglich ist.The geometric embodiment of the invention is not limited to the relatively simple geometries listed here. In particular, in the embodiment as a metal filter, the individual filter elements can also be arranged in a very complex form. It is important that according to the invention for a large number of filter channels each have a shunt and that these shunt channels are geometrically connected so that in the case of complete blockage of the filter elements a free flow of the exhaust gas through the shunt channels is possible.
Eine weitere Ausführungsform der Erfindung verwendet katalytisch beschichtete Filterelemente. Dabei kann für die vorderen und hinteren Filterelemente eine unterschiedliche Beschichtung gewählt werden. Auch die Nebenschluß-Kanäle können katalytisch beschichtet sein. Dabei kann die gleiche oder eine unterschiedliche Beschichtung wie für die Filterkanäle gewählt werden. Zum Beispiel verläuft die Strömung im Fall eines voll beladenen Filters zu einem großen Teil durch die Nebenschluß-Kanäle. Es ist daher hilfreich, die Nebenschluß-Kanäle mit einem Oxidationskatalysator zu beschichten, um möglichst viel Exothermie bei der Regeneration zu erzeugen. Im Gegenzug ist es sinnvoll, die Beschichtung der Filterwände eher in Richtung eines erniedrigten Rußzündtemperatur hin zu optimieren. Die Erfindung ist besonders vorteilhaft bei Verwendung von neuartigen hochporösen Filtermaterialien. Diese Materialien zeigen im vollständig unbeladenen Zustand nur eine mäßige Filtereffizienz. Die Filtereffizienz steigt dann im beladenen Zustand durch die Ausbildung eines Filterkuchens an. Ein Filtersystem gemäß der vorliegen Erfindung wird so ausgelegt, daß für eine vorgewählte ,Norm-Beladung' jeweils 50 % des Abgases durch den Nebenschluß und 50 % durch die Filtereinheiten geht. Der Gegendruck bei Norm-Beladung beträgt die Hälfte des bei vollständiger Beladung auftretenden Gegendrucks. Bei dieser Auslegung gehen beim unbeladenen Filter mehr als 80 % der Abgase durch beide Filterelemente so daß auch hier eine fast vollständige Rußabschei- düng erreicht wird. Mit zunehmender Beladung des Filters sinkt dann zwar der Anteil des doppelt gefilterten Gases, dafür steigt aber die Filtereffϊzienz des porösen Filtermaterials. Auf diese Weise wird über den gesamten Normal-Betriebsbereich ein guter Abscheidegrad erreicht. Another embodiment of the invention uses catalytically coated filter elements. In this case, a different coating can be selected for the front and rear filter elements. The shunt channels can also be catalytically coated. In this case, the same or a different coating can be selected as for the filter channels. For example, in the case of a fully loaded filter, the flow is largely through the shunt channels. It is therefore helpful to coat the shunt channels with an oxidation catalyst in order to generate as much exotherm as possible during the regeneration. In return, it makes sense to optimize the coating of the filter walls in the direction of a reduced soot ignition temperature. The invention is particularly advantageous when using novel highly porous filter materials. These materials show only a moderate filter efficiency when completely unloaded. The filter efficiency then increases in the loaded state by the formation of a filter cake. A filter system according to the present invention is designed so that for a preselected 'standard load' 50% of the exhaust gas passes through the shunt and 50% through the filter units. The back pressure at standard load is half of the counter pressure occurring at full load. In this design, the unloaded filter more than 80% of the exhaust gases go through both filter elements so that here also almost a complete Rußabschei- fertilg is reached. As the loading of the filter increases, the proportion of the double-filtered gas decreases, but the filter efficiency of the porous filter material increases. In this way, a good degree of separation is achieved over the entire normal operating range.

Claims

Patentansprüche claims
1. Filteraggregat aus wenigsten zwei in einem Abstand hintereinandergeschalteten Filtereinheiten, die zur Entfernung von Ruß aus dem Abgas von Dieselmotoren nacheinander vom Abgas durchflössen werden, dadurch gekennzeichnet, daß jede Filtereinheit einen oder mehrere Nebenschlüsse aufweist, die in zwei aufeinanderfolgenden Filtereinheiten seitlich gegeneinander versetzt sind und wobei zwischen den Nebenschlüssen der aufeinanderfolgenden Filtereinheiten ein verstopfungsfreier Strömungsweg besteht.1. Filter unit of at least two spaced-apart filter units, which are flowed through to remove soot from the exhaust gas of diesel engines in succession from the exhaust gas, characterized in that each filter unit has one or more shunts, which are laterally offset from each other in two successive filter units and wherein there is a blockage-free flow path between the shunts of the successive filter units.
2. Filteraggregat nach Anspruch 1, dadurch gekennzeichnet, daß die Nebenschlüsse so dimensioniert sind, daß sie bei vollständig regeneriertem Filter 10 bis 50 % des Volumenstromes des Abgases aufnehmen.2. Filter unit according to claim 1, characterized in that the shunts are dimensioned so that they absorb 10 to 50% of the volume flow of the exhaust gas at fully regenerated filter.
3. Filteraggregat nach Anspruch 2, dadurch gekennzeichnet, daß die hintereinandergeschalteten Filtereinheiten jeweils ein Filter ausgewählt aus der Gruppe bestehend aus Wandflußfilter, Keramikschaumfilter, Metallschaumfilter, Metallfilter und Taschenfilter enthalten und die Nebenschlüsse durch Abgasleitungen gebildet sind, die seitlich an den jeweiligen Filtern vorbei- geführt sind.3. Filter unit according to claim 2, characterized in that the filter units connected in series each contain a filter selected from the group consisting Wandflußfilter, ceramic foam filter, metal foam filter, metal filter and bag filter and the shunts are formed by exhaust pipes, the led laterally past the respective filters are.
4. Filteraggregat nach Anspruch 3, dadurch gekennzeichnet, daß die Nebenschlüsse mit laminaren Reibungsverlusten ausgerüstet sind.4. Filter unit according to claim 3, characterized in that the shunts are equipped with laminar friction losses.
5. Filteraggregat nach Anspruch 4, dadurch gekennzeichnet, daß in den Nebenschlüssen monolithische Durchfluß- Wabenkörper angeordnet sind.5. Filter unit according to claim 4, characterized in that in the shunts monolithic flow honeycomb body are arranged.
6. Filteraggregat nach Anspruch 5, dadurch gekennzeichnet, daß die Filter und/oder die Durchfluß- Wabenkörper katalytisch beschichtet sind.6. Filter unit according to claim 5, characterized in that the filter and / or the flow honeycomb body are coated catalytically.
7. Filteraggregat nach Anspruch 6, dadurch gekennzeichnet, daß die Filter und/oder die Durchfluß- Wabenkörper mit einem Oxidationskataly- sator beschichtet sind.7. Filter unit according to claim 6, characterized in that in that the filters and / or the flow-through honeycomb bodies are coated with an oxidation catalytic converter.
8. Filteraggregat nach Anspruch 7, dadurc h g e ke nnz e i c hnet , daß die Konzentration der Beschichtung mit dem Oxidationskatalysator auf den8. Filter unit according to claim 7, characterized in that the concentration of the coating with the oxidation catalyst on the
Durchfluß- Wabenkörpern größer ist als auf den Filtern.Durchfluß- honeycomb bodies is greater than on the filters.
9. Filteraggregat nach Anspruch 1 , dadurc h geke nnz e i c hnet , daß die zwei hintereinandergeschalteten Filtereinheiten jeweils ein Wandflußfilter enthalten und die Nebenschlüsse dadurch gebildet sind, daß ein Teil der Strömungskanäle der Wandflußfilter als Durchflußkanäle ausgebildet sind..9. Filter unit according to claim 1, dadurc h geke nnz e i c hnet that the two filter units connected in series each contain a Wandflußfilter and the shunts are formed by the fact that a part of the flow channels of Wandflußfilter are designed as flow channels.
10. Filteraggregat nach Anspruch 9, d adurc h ge ke nnze i c hnet , daß der Abstand der Wandflußfilter untereinander das 1 bis 200-fache eines Ka- naldurchmessers beträgt.10. Filter unit according to claim 9, characterized in that the distance between the Wandflußfilter is between 1 and 200 times a channel diameter.
11. Filteraggregat nach Anspruch 10, dadurch g e ke nnze i chnet , daß die Wandflußfilter aus mehreren quaderförmigen Filterelementen unterschiedlicher Länge aufgebaut sind, von denen jedes Element einige Durchflußka- näle aufweist, wobei die Elemente unterschiedlicher Länge in den aufeinanderfolgenden Wandflußfiltern komplementär zueinander angeordnet und miteinander zur Bildung eines monolithischen Filteraggregats verzahnt sind.11. Filter unit according to claim 10, characterized in that the wall-flow filters are made up of a plurality of parallelepiped-shaped filter elements of different lengths, each element having a plurality of flow channels, the elements of different lengths being arranged complementary to one another in the successive wall flow filters toothed to form a monolithic filter unit.
12. Filteraggregat nach Anspruch einem der Ansprüche 9 bis 11, dadurc h gekennze i c hnet , daß die Wandflußfilter und ihre Durchflußkanäle katalytisch beschichtet sind.12. Filter unit according to claim one of claims 9 to 11, dadurc h gekennze i c hnet that the Wandflußfilter and their flow channels are coated catalytically.
13. Verfahren zur Entfernung von Ruß aus dem Abgas eines Dieselmotors mit den folgenden Verfahrensschritten: a) Leiten des Abgasstromes durch eine erste Filtereinheit mit Nebenschluß, wobei die Rußfracht eines ersten Teilstromes des Abgases in der ersten Filtereinheit entsprechend ihrem Filterwirkungsgrad abgelagert wird, während ein zweiter13. A method for removing soot from the exhaust gas of a diesel engine comprising the steps of: a) directing the exhaust gas flow through a first filter unit with shunt, wherein the soot load of a first partial flow of the exhaust gas is deposited in the first filter unit according to their filter efficiency, while a second
Teilstrom des Abgases die erste Filtereinheit über den Nebenschluß ungefiltert passiert und danach, b) Leiten des Abgasstromes durch eine zweite Filtereinheit mit Nebenschluß, wobei die Rußfracht eines dritten Teilstromes des Abgases in der zweiten Filtereinheit entsprechend ihrem Filterwirkungsgrad abgelagert wird, während ein vierter Teilstrom des Abgases die zweite Filtereinheit über den Nebenschluß ungefiltert passiert.Partial flow of the exhaust gas passes through the first filter unit unfiltered via the shunt and thereafter, b) passing the exhaust gas flow through a second filter unit with shunt, wherein the soot load of a third partial stream of the exhaust gas is deposited in the second filter unit according to their filter efficiency, while a fourth partial flow of the exhaust gas passes through the second filter unit unfiltered via the shunt.
14. Verfahren nach Anspruch 13 , dadurch gekennzeichnet, daß durch strömungstechnische Maßnahmen sichergestellt ist, daß der dritte Teilstrom überwiegend durch den zweiten Teilstrom gebildet wird und seine Ruß- fracht in der zweiten Filtereinheit entsprechend ihrem Filterwirkungsgrad abgelagert wird, während der vierte Teilstrom überwiegend vom ersten, schon von Ruß befreitem, Teilstrom gebildet wird.14. The method according to claim 13, characterized in that it is ensured by fluidic measures that the third partial flow is predominantly formed by the second partial flow and its soot is deposited in the second filter unit according to their filter efficiency, while the fourth partial flow predominantly from the first , already freed from soot, partial flow is formed.
15. Verfahren nach Anspruch 10, dadurch gekennzeichnet, daß der Abgasstrom nach Verlassen der zweiten Filtereinheit über mindestens eine weitere Filtereinheit mit Nebenschluß geleitet wird, wobei die Aufteilung des Abgasstromes und die Rußablagerung wie in der ersten oder zweiten Filtereinheit erfolgt.15. The method according to claim 10, characterized in that the exhaust gas stream is passed after exiting the second filter unit via at least one further filter unit with shunt, wherein the division of the exhaust gas stream and the soot deposition takes place as in the first or second filter unit.
16. Verfahren nach Anspruch 1 , dadurch gekennzeichnet, daß eine aktive Regeneration der Filtereinheiten eingeleitet wird, wenn der Massenstrom durch die Nebenschlüsse von anfänglich 5 bis 30 % durch die Rußbeladung auf 40 bis 70 % des gesamten Abgasmassenstromes angewachsen ist.16. The method according to claim 1, characterized in that an active regeneration of the filter units is initiated when the mass flow is increased by the shunts of initially 5 to 30% by the soot load to 40 to 70% of the total exhaust gas mass flow.
17. Verfahren nach einem der Ansprüche 10 bis 12, dadurch gekennzeichnet, daß die Nebenschlüsse der Filtereinheiten jeweils an der Filtereinheit vorbeigeführt sind.17. The method according to any one of claims 10 to 12, characterized in that the shunts of the filter units are guided past each of the filter unit.
18. Verfahren nach Anspruch 16, dadurch gekennzeichnet, daß Filtereinheiten und/oder Nebenschlüsse katalytisch beschichtet sind.18. The method according to claim 16, characterized in that filter units and / or shunts are catalytically coated.
19. Verfahren nach einem der Ansprüche 10 bis 12, dadurch gekennzeichnet, daß die Nebenschlüsse der Filtereinheiten jeweils durch die Filtereinheiten hin- durchgefuhrt sind.19. The method according to any one of claims 10 to 12, characterized that the shunts of the filter units are each passed through the filter units.
20. Verfahren nach Anspruch 18, dadurch gekennzeichnet, daß Filtereinheiten und/oder Nebenschlüsse katalytisch beschichtet sind 20. The method according to claim 18, characterized in that filter units and / or shunts are catalytically coated
PCT/EP2006/004253 2005-05-21 2006-05-06 Highly effective non-clogging filter unit WO2006125516A1 (en)

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WO2020068111A1 (en) * 2018-09-28 2020-04-02 Cummins Emission Solutions Inc. Systems and methods for dynamic control of filtration efficiency and fuel economy
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CN113959061A (en) * 2021-11-24 2022-01-21 美的集团武汉制冷设备有限公司 Reminding method and device for fresh air equipment, storage medium and fresh air equipment
CN114922718A (en) * 2022-04-24 2022-08-19 潍柴动力股份有限公司 Shunting heat preservation bush formula SCR device

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