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    • 专利摘要:
    PARTICLES FILTER. An object of the invention is to eliminate the deposit of combustion residues in a wall-flow particulate filter while reducing PM capture rate drops. To achieve the above objective, the invention features a wall-flow particle filter delimited by porous partition walls having pores of a size that allows waste and waste aggregates to pass through. In the filter, a cover layer having pores smaller than the pores of the partition walls is provided in a region of the partition walls, from an upstream end thereof to a position before a downstream end thereof.
    公开号:BR112014024072B1
    申请号:R112014024072-8
    申请日:2012-03-30
    公开日:2021-05-04
    发明作者:Shigeki Nakayawa；Hiromasa Nishioka；Daichi Imai；Hiroshi Otsuki
    申请人:Toyota Jidosha Kabushiki Kaisha；
    IPC主号:
    专利说明:

    FIELD OF TECHNIQUE
    [001] The invention relates to a particulate filter that is arranged in a passage of the exhaust gas of an internal combustion engine. BACKGROUND TECHNIQUE
    [002] Conventional particulate filters for capturing particulate matter (PM) that is present in the exhaust gas of an internal combustion engine include wall-flow particulate filters in which first passes, the upstream end of which is blocked by plugs, and second passages, the downstream end of which is blocked by plugs, are alternately arranged and in which porous partition walls are arranged between the first passages and the second passages.
    [003] Wall flow particle filters that have been proposed include wall flow particle filters provided with holes punched in the plug portions of the second passes (see, for example, Patent Literature 1). Other wall-flow particle filters that have been proposed include wall-flow particle filters that support a metal of electronegativity lower than that of calcium (Ca) (see, for example, Patent Literature 2). Additional cases of proposed wall flow particle filters include filters in which a catalyst support layer is formed in part on the upstream side of the wall faces of the passages (see, for example, Patent Literature 3).
    [004] Patent Literature 1: Japanese Patent Application Publication 2004130229 (JP 2004-130229 A)
    [005] Patent Literature 2: Japanese Patent Application Publication 200112229 (JP 2001-12229 A)
    [006] Patent Literature 3: International Patent Application 2008/126331 (WO 2008/126331) SUMMARY OF THE INVENTION
    [007] Components derived, for example, from fuel additives and lubricants (engine oil) in the gas and exhaust flowing into the particulate filter can join with the particulate filter or the combustion chambers of the internal combustion engine and cause compounds that are referred to as combustion residues. For example, combustion residues are here a compound such as calcium sulphate (CaSO4) or calcium phosphate (Ca3(PO4)2) or magnesium sulphate (MgSO4). These combustion residues are trapped in the particulate filter in the same way as PM, but are not removed from the particulate filter even when PM is subjected to an oxidative removal process. In this way, aggregates of combustion residues are deposited in the particle filter, which can lead to clogging of the pores of the partition walls.
    [008] Conceivable methods to address this problem may involve, for example, increasing the pore size of the partition walls or producing holes through the buffer portions of the second passes, as disclosed in patent literature 1. However, the above approach may lead to a situation where PM having a particle size comparable to or smaller than that of the combustion residues and combustion residue aggregates slips through the particulate material filter along with the combustion residues.
    [009] In view of the above, it is an object of the invention to present a technology that allows to suppress the deposit of combustion residues in a particle filter with wall flow while reducing the drops in the PM capture rate.
    [010] In order to solve the above problems, the invention is a wall-flow particle filter having a plurality of passages delimited by porous partition walls that have pores of a size that allows combustion residues and aggregates. combustion residues pass through, such that a cover layer having pores smaller than the pores of the partition walls is produced, in a region of the partition walls, from an upstream end of it to the front of a downstream end of it. .
    [011] In further details, the particle filter according to the invention is configured to have a plurality of first passages, the ends of which, on an upstream side in the flow direction of the discharge gas, are blocked; a plurality of second passages, the ends of which, on a side downstream in the discharge gas flow direction, are blocked; porous partition walls, which are elements separating the first passages from the second passages and which have pores of a size that allow combustion residues to pass through, and a porous cover layer, which is produced in part of a region of the partition walls, from an upstream end of it to a position before a downstream end of it that has pores smaller than the pores of the dividing walls.
    [012] As a result of diligent experimentation and verification, the inventors of the application have verified that combustion residues and combustion residue aggregates (hereinafter collectively referred to as "combustion residues") are generated or readily deposited in the vicinity of the ends to downstream of the second passes of the wall flow particle filter. The inventors of the application have also found that PM easily passes through the partition walls upstream of the locations, in the second passages, in which combustion residues are easily generated or deposited.
    [013] The particle filter of the invention, therefore, is configured to have a cover layer having pores, smaller than those of the partition walls, in part of a region of the partition walls, from its upstream end to a position before the downstream end. Preferably, the cover layer is provided at least on the dividing walls enclosing the second passages, from between the dividing walls enclosing the first passages and the dividing walls enclosing the second passages.
    [014] In the particulate filter having such a configuration, most of the PM is trapped in the pores of the cover layer, while most of the combustion residues pass through the pores of the partition walls, in which the cover layer is not provided. As a result, it becomes possible to eliminate the deposit of combustion residues while reducing PM capture rate drops.
    [015] The cover layer can be a dispersion, in which the particles are substantially homogeneously dispersed. In this case, a large number of gaps (pores) are formed between the particles and therefore even more PM can be trapped in the covering layer. As a result, the amount of PM reaching the region in the vicinity of the downstream end of the partition walls (that is, the region of the partition walls in which the covering layer is not provided) is further reduced. In this way, it is possible to keep the amount of PM that slips through the pores of the dividing walls to a minimum.
    [016] The particulate filter of the invention can be configured such that a metal having the ability to oxidize (for example, a platinum group metal (Pt)) is provided in the region in the vicinity of the downstream end of the dividing walls, that is, the region of the dividing walls, in which the covering layer is not provided.
    [017] As described above, most of the PM is trapped in the pores of the cover layer in a region of the split walls, from the upstream end to the front of the downstream end (region of the split walls in which the coverage is provided). However, the small remaining amount of PM can reach, in some cases, the proximity of the downstream end of the partition walls. In this case, a small amount of PM can slip through the pores of the partition walls and seep out of the particulate filter.
    [018] When, in contrast, the metal having oxidation capacity is supported in the region of the partition walls in the vicinity of the downstream end, that is, in the region of the partition walls in which the covering layer is not provided, the PM which reaches the proximity of the downstream end of the partition walls is oxidized. As a result, it becomes possible to keep the amount of PM that slips through the particulate filter to a minimum.
    [019] Next, the covering layer of the invention can be configured to have a metal, whose ionization tendency is greater than that of a main component of combustion residues. As described above, combustion residues are readily generated in the partition walls in the vicinity of the downstream ends of the second passages, i.e. in the portions of the partition walls in which the covering layer is not provided. Meanwhile, a small amount of combustion residues can be generated or be deposited on the partition walls in the vicinity of the upstream ends of the second passages, i.e. on the portions of the partition walls on which the covering layer is provided. In this way, the pores of the cover layer can become clogged by combustion residues when the particulate filter is used over long periods of time.
    [020] When the cover layer has a metal whose ionization tendency is greater than that of the main component of the combustion residues, in contrast, other components in the exhaust gas are adsorbed or absorbed in the cover layer in preference to this main component. As a result, the main component of the combustion residues does not easily bind to other components in the discharge gas on the surface of the cover layer. That is, the generation and deposit of combustion residues on the surface of the cover layer is eliminated.
    [021] Here, for example, Ca is the main component of combustion residues. In that case, the cover layer can be configured to have a metal, such as potassium (K) or barium (Ba), whose ionization tendency is greater than that of Ca. Sulfur (S), phosphorus (P) or the like in the discharge gas they are adsorbed on the cover layer in preference to Ca, in the case where the cover layer has K or Ba. As a result, combustion residues such as CaSO4 or Ca3(PO4) are not easily generated on the surface of the cover layer.
    [022] The partition walls of the invention can be formed in such a way that the average pore size of their pores ranges from 25 µm to 50 µm. The cover layer can be a dispersion of particles (powder) having an average particle size ranging from 1 µm to 10 µm.
    [023] Findings by the inventors of the application revealed that combustion residues and combustion residue aggregates can slip through the pores of the partition walls when the average pore size of the partition walls is approximately 25 µm or greater. In other words, combustion residues and combustion residue aggregates can slide through the pores of the partition walls when the average pore size of the partition walls is approximately 250 or more times the particle size of the combustion residues. However, the strength of the base material that makes up the dividing walls may decrease when the average pore size is greater than 50 µm. Therefore, it becomes possible to suppress the deposit of combustion residues, while reducing the drops in the resistance of the base material, when the dividing walls are formed in such a way that their average pore size ranges from 25 µm to 50 µm.
    [024] Findings by the inventors of the application have demonstrated that gaps of an appropriate size for capturing PM are formed between particles when the average particle size of the particles forming the covering layer is equal to or greater than 1 µm. Here, the pressure loss in the particulate material filter sharply increases when the average particle size of the particles exceeds 10 µm. Therefore, even more PM can be captured, while reducing the increases in pressure loss, when the cover layer is composed of the dispersion of particles having an average particle size ranging from 1 µm to 10 µm. The term "average particle size" here represents not the average particle size of the particles (primary particles) that are used to produce the dispersion, but the average particle size of the particles (secondary particles) at the time when the dispersion is stable ( it is complete).
    [025] The method for forming the covering layer (dispersion) on the surface of the dividing walls is not particularly limited. As an example, one method may resort to that which involves coating the surface of the partition walls with a slurry having primary particles, followed by drying and heating. In such a method, the pore size of the cover (dispersion) layer can be adjusted based on the particle size of the primary particles in the slurry. In other words, the particle size of the secondary particles that make up the dispersion can be adjusted based on the particle size of the primary particles in the slurry. In this way, the average pore size of the cover layer can be brought to a desired size (ie, a size suitable for capturing PM) by setting the particle size of the primary particles in such a way that the average particle size of the secondary particles range from 1 µm to 10 µm.
    [026] The particle size of the primary particles is smaller than the particle size of the secondary particles and the particle size of the secondary particles is smaller than the pore size of the partition walls. As a result, the primary particles can, in some cases, penetrate the pores of the partition walls when the partition walls are coated with the slurry. The cover layer can therefore be formed according to a method which involves applying the slurry after the pores of the partition walls have been filled with a burnable substance, a method which involves hydrophobizing the partition walls and using a liquid having water or a water-soluble organic matter as a liquid slurry vehicle or a method involving causing a volatile solvent to be held in the pores of the partition walls and then applying the slurry having the volatile solvent as a main dispersion vehicle.
    [027] The invention allows to eliminate the deposit of combustion residues in a particle filter with wall flow while reducing the drops in the capture rate of the PM. BRIEF DESCRIPTION OF THE DRAWINGS
    [028] [Figure 1] Figure 1 is a longitudinal sectional diagram illustrating a schematic configuration of a particle filter in which the invention is used.
    [029] [Figure 2] Figure 2 is a cross-sectional diagram illustrating a schematic configuration of a particle filter in which the invention is used.
    [030] [Figure 3] Figure 3 is a diagram of the enlarged section of the dividing walls in which a covering layer is produced.
    [031] [Figure 4] Figure 4 is a diagram schematically illustrating the configuration of a cover layer.
    [032] [Figure 5] Figure 5 is a diagram illustrating the relationship between the average particle size of the particles that make up a cover layer, the pressure loss of a particle filter and the amount of PM that slips through the filter of particles.
    [033] [Figure 6] Figure 6 is a diagram illustrating the configuration of the partition walls that involve a second passage.
    [034] [Figure 7] Figure 7 is a diagram schematically illustrating the configuration of a covering layer in a second working example.
    [035] [Figure 8] Figure 8 is a diagram illustrating another example of covering layer configuration in the second working example.
    [036] [Figure 9] Figure 9 is a diagram schematically illustrating the configuration of the dividing walls, in a third working example, in a portion in which a covering layer is not provided.
    [037] [Figure 10] Figure 10 is a diagram schematically illustrating another configuration of the dividing walls, in a third working example, in a portion in which a covering layer is not provided.
    [038] [Figure 11] Figure 11 is a diagram illustrating another example of a covering layer configuration. METHODS FOR CARRYING OUT THE INVENTION
    [039] Specific embodiments of the invention will be explained below based on the accompanying drawings. Unless otherwise stated, the dimensions, materials, shapes of the constituent parts and the relative disposition of the constituent parts and other characteristics described in the following embodiments are in no way intended to limit the technical scope of the invention to these characteristics only . WORK EXAMPLE 1
    [040] A first working example of the invention will be explained first based on figure 1 to figure 6. Here, figure 1 is a diagram of the longitudinal section of a particle filter, in which the invention is used and figure 2 is a cross-sectional diagram of a particle filter in which the invention is used.
    [041] A particle filter 1 illustrated in figures 1 and 2 is disposed in a passage of the exhaust gas of an internal combustion engine and captures the PM that is present in the exhaust gas of the internal combustion engine. A column 3 base material is provided within a cylindrical housing 2 of the particulate filter 1.
    [042] A plurality of passages 4, 5 extending in the axial direction (flow direction of the discharge gas) is formed in the base material 3. This plurality of passages 4, 5 is arranged in the form of a honeycomb. In other words, the base material 3 is formed in such a way as to define the plurality of passages 4, 5 which are arranged in the form of a honeycomb. The number of passages 4, 5 illustrated in figures 1 and 2 is merely exemplary and can be established, when necessary, in accordance with the specifications of the vehicle or of the internal combustion engine.
    [043] Between the plurality of passages 4, 5, the upstream ends of the passages 4, in the flow direction of the discharge gas, are blocked with the plugs 40. Between the plurality of passages 4,5, the ends downstream of the Remaining passages 5, in the direction of flow of the discharge gas, are blocked with plugs 50. The passages 4 and passages 5 are alternately arranged. Next, passages 4 will be referred to as first passes 4 and passages 5 as second passes 5.
    [044] Locations (partition walls) 30 of the base material 3 that are positioned between the first passages 4 and the second passages 5 are formed of a porous body. Only the dividing walls 30 of the base material 3 can be formed from a porous body; alternatively, all of the base material 3 can be formed from a porous body. Conventional materials that are suitable for capturing PM in the off-gas can be used here as the porous body material. In terms of strength and heat resistance, however, a ceramic is preferably used as represented, for example, by silicon carbide, silicon nitride, cordierite, zirconium dioxide, titanium dioxide, alumina, silica, mullite, lithium silicate aluminum and zirconium phosphate.
    [045] The partition walls 30 are formed in such a way that the average pore size of the pores formed in the partition walls 30 is larger than the combustion residues and combustion residue aggregates. Specifically, the partition walls 30 are formed in such a way that the average pore ranges from 25 µm to 50 µm. Here, 25 μm is the minimum value that allows most combustion residues and combustion residue aggregates to slide and 50 μm is the minimum pore size value that is judged to compromise the strength and durability of the material. base 3.
    [046] A porous covering layer 300 is produced on the surface of the dividing walls 30 surrounding the second passages 5. The covering layer 300 is provided in a region, of the dividing walls 30, from its upstream end at the flow direction of the discharge gas to a position before the downstream end. That is, the position of the upstream end of cover layer 300 in the flue gas flow direction coincides with that of the upstream ends of dividing walls 30, but the downstream end of cover layer 300 is positioned more towards the front (upstream) side than the downstream ends of the dividing walls 30.
    [047] As a result of diligent experimentation and verification, the inventors of the application have found that with the inflow of the exhaust gas into the second passages 5, most of the PM in the exhaust gas readily flows into the pores that are present in the the upstream end of the partition walls 30 to the front of the downstream end, while combustion residues and combustion residue aggregates are readily generated and are deposited in the vicinity of the downstream end of the division walls 30. By establishing the end downstream of the cover layer 300 in light of this finding, it becomes possible to allow most of the PM to flow into the pores of the cover layer 300 and most of the combustion residues to flow into the pores of the partition walls 30 , in which the cover layer 300 is not provided.
    [048] For example, the cover layer 300 is a solid state dispersion, in which substantially spherical particles 301 are dispersed and layered homogeneously, as illustrated in Figure 3. Gaps 302 are formed between the particles 301 and the particles 301 , as illustrated in Figure 4 in the case where the cover layer 300 is composed of such a dispersion. These 302 gaps act as pores to capture PM.
    [049] Particles of a ceramic identical to that of the base material 3 can be used as the 301 particles that make up the dispersion, but preferably they are the used particles of a metal (eg a Pt group metal) having the ability to oxidation. When the dispersion is made of Pt group metal particles, the PM trapped in the spans 302 is quickly oxidized and removed in the case where the high temperature exhaust gas, or the exhaust gas having an unburnt fuel component, flows into inside the particle filter 1.
    [050] The average particle size of the 301 particles that make up the dispersion preferably ranges from 1 µm to 10 µm. This is because the amount of PM that slips through particulate filter 1 is large in the case where the average particle size of the particles is less than 1 µm, while the pressure loss in particulate filter 1 is greater in the case where the Average particle size is greater than 10 µm, as illustrated in Figure 5. Therefore, PM can be trapped, while eliminating increases in pressure loss, when the cover (dispersion) layer is composed of particles having an average size. particle sizes ranging from 1 µm to 10 µm.
    [051] Preferably, the passage cut area of the portion of the second passes 5 in which the cover layer 300 is provided is equal to the passage cut area of the portion in which the cover layer 300 is not provided. In this way, the thickness of the places where the cover layer 300 is provided may be less than the thickness of the places where the cover layer 300 is not provided, in the dividing walls 30 surrounding the second passages 5, as illustrated. in figure 3 described above. In other words, the diameter A1 of the second passages 5 in the portion where the covering layer 300 is to be provided can be set to be larger, in the state where the covering layer 300 is not provided in the second passages 5, than the diameter A2 of the second passages 5 in the portion where the cover layer 300 is not to be provided, as illustrated in figure 6.
    [052] The method for forming the cover layer 300 is not particularly limited, but, as an example, a method may resort to that which involves coating the surface of the partition walls 30 with a slurry that includes metal particles from the Pt group, followed by drying and heating. In this case, it is sufficient that the average particle size of the metal particles (primary particles) is smaller than that of the 301 particles (secondary particles) after the formation of the covering layer 300 and that the average particle size of the secondary particles remains in a range of 1 µm to 10 µm.
    [053] The average particle size of the primary particles in the slurry is less than the average pore size of the partition walls 30 when the average pore size of the partition walls 30 is set to range from 25 µm to 50 µm and the average particle size of the 301 particles is set to range from 1 µm to 10 µm. In this way, the primary particles can, in some cases, penetrate the pores of the partition walls 30 when the partition walls 30 are coated with the slurry. When drying and/or heating is carried out in the state where the primary particles have penetrated into the pores of the partition walls 30, the pore size of the partition walls 30 may decrease and the pores of the partition walls 30 may become blocked. The pressure drop in particulate filter 1 can increase unnecessarily in such a case.
    [054] Therefore, the cover layer 300 is preferably formed using a method that involves applying the slurry after the pores of the partition walls 30 have been filled with a substance that burns in a drying process or a heating process, a method which involves hydrophobizing the partition walls 30 and using a liquid that has water or a water-soluble organic matter as a liquid vehicle of the slurry or a method which involves causing a volatile solvent to be maintained in the pores of the partition walls 30 and then applying the slurry having the volatile solvent as a main dispersion vehicle.
    [055] In the particle filter 1 configured as described above, the exhaust gas which flows into the particle filter 1 first flows into the second passages 5. The exhaust gas which has flown into the second passages 5 then flows into inside the first passages 4 through the spans 302 of the covering layer 300 and the pores of the dividing walls 30. At that time, most of the PM in the exhaust gas is trapped in the covering layer 300. The combustion residues in the flue gas discharge and combustion residues that are formed in the second passages 5 flow into the first passages 4 through the pores of the region (region near the downstream end) of the dividing walls 30, in which the covering layer 300 is not provided . The exhaust gas and combustion residues which have flown into the first passages 4 are discharged downstream of the particulate filter 1, through the openings at the ends downstream of the first passages 4.
    [056] Therefore, it is possible to eliminate the deposit of combustion residues in particulate filter 1 while reducing the PM capture rate drops of particulate filter 1. WORK EXAMPLE 2
    [057] A second working example of the invention will be explained below based on figure 7 to figure 8. Aspects that are different from those of the first working example described above will be explained here, while the explanation of identical aspects will be omitted.
    [058] The first working example described above and the working example differ in that now the covering layer 300 has a metal whose ionization tendency is greater than that of Ca. As explained in the first working example, residues of combustion are generated and are readily deposited on the partition walls 30 in the vicinity of the downstream ends of the second passages 5, i.e. on the portions of the partition walls 30 in which the covering layer 300 is not provided. In some cases, however, a small amount of combustion residues may be generated in the partition walls 30 in the vicinity of the upstream ends of the second passages 5, i.e. in the portions where the covering layer 300 is provided on the partition walls 30 In this way, combustion residues can be deposited on the covering layer 300 and the gaps 302 of the covering layer 300 can become blocked when the usage time of the particulate filter 1 is prolonged.
    [059] When the covering layer 300 has a metal whose ionization tendency is greater than that of the main component of the combustion residues, in contrast, other components in the exhaust gas are adsorbed or absorbed into the covering layer 300 in preference to that main component. As a result, the main component of the combustion residues does not easily bind to other components in the discharge gas on the surface of the covering layer 300. That is, the generation of the combustion residues on the surface of the covering layer 300 is eliminated.
    [060] For example, Ca is here considered to be the main component of combustion residues. Ca binds with S, P or oxygen (O2) in the exhaust gas to generate combustion residues (eg, CaSO4 or Ca3(PO4)2.
    [061] When the cover layer 300 includes a metal such as K, Ba or the like having a greater tendency to ionize than that of Ca, then S, P or the like in the discharge gas bond with K or Ba in preferably Ca. As a result, combustion residues such as CaSO4 or Ca3(PO4)2 are not easily generated on the surface of the cover layer 300.
    [062] A method of incorporating K or Ba within the overlay layer 300 may involve, for example, mixing, in the particles 301 that make up the overlay layer 300, particles 303 of K or Ba having an average particle size identical to that of particles 301 as illustrated in Figure 7. Particles 303 of K or Ba can be induced to be supported on the surface of cover layer 300 as illustrated in Figure 8.
    [063] The working example as described above allows to further reliably eliminate the generation and deposition of combustion residues in the cover layer 300. As a result, the PM capture capacity of the cover layer 300 can be maintained through long periods of time.
    [064] In the working example, a case was explained, in which the covering layer 300 has a metal, whose ionization tendency is greater than that of Ca, but the covering layer 300 can be defined to have a metal, whose ionization tendency is greater than that of magnesium (Mg); alternatively, cover layer 300 can be defined to have both a metal whose tendency to ionize is greater than that of Ca and a metal whose tendency to ionize is greater than that of Mg. WORK EXAMPLE 3
    [065] A third working example of the invention will be explained below based on figure 9 to figure 10. Aspects that are different from those of the first working example described above will be explained here, while the explanation of identical aspects will be omitted.
    [066] The first working example described above and the working example differ in that here a metal having oxidation capacity is supported in those regions of the dividing walls 30 surrounding the second passages 5, where the covering layer 300 is not provided . Most of the PM flowing into the particulate filter 1 (second passes 5) is trapped in the pores of the cover layer 300 in the region extending from the upstream end to the front of the downstream ends of the second passes 5. However , a small amount of PM may reach the dividing walls 30 in the vicinity of the downstream ends of the second passages 5 (i.e. the portions of the dividing walls 30 in which the covering layer 300 is not provided). In that case, a small amount of PM can slip through the pores of the partition walls 30 and flow out of the particulate filter 1.
    [067] When, in contrast, a metal having oxidizing capability is supported on the dividing walls 30 in the vicinity of the downstream ends of the second passages 5 (i.e., on the portions of the dividing walls 30, in which the covering layer 300 is not supplied), the PM reaching the proximity of the downstream ends of the second passages 5 comes into contact with the metal and is oxidized. As a result, it becomes possible to keep the amount of PM that slips through the particle filter 1 even smaller.
    [068] Methods that can be used to induce metal having oxidizing capability to be supported in a region of the dividing walls 30 in which the cover layer 300 is not provided may involve, for example, providing a cover layer that has metal particles of the Pt group, symbolized by Pt (hereinafter referred to as "catalyst cover layer") 310 on the surface of the partition walls 30, as illustrated in Figure 9. A method can also be used in which a layer of Catalyst coating 310 is also provided on the inner wall surface of the pores 311 of the partition walls 30, in addition to the surface of the partition walls 30, as illustrated in Figure 10. In that case, the average pore size of the partition walls 30 and the thickness of the catalyst cover layer 310 are set in such a way that the average pore size after the catalyst cover layer 310 has been provided ranges from 25 µm to 50 µm. The catalyst cover layer 310 described in the working example can be provided only on the partition walls 30 in the portion where the cover layer 300 is not provided or it may be provided over the entirety of the partition walls 30.
    [069] In the work example described above, the PM that does not get trapped in the cover layer 300, among the PM that flows into the particle filter 1 (i.e., the PM that flows into the second passes 5), it is oxidized on the dividing walls 30 near the downstream ends of the second passages 5. As a result, it becomes possible to keep the amount of PM sliding through the particle filter 1 even lower.
    [070] The second working example described above and the third working example can be combined. Specifically, a metal having a greater tendency to ionization than that of the main component of the combustion residues can be incorporated in the covering layer 300 and a metal having oxidizing capacity can be induced to be supported on the partition walls 30 in a region in the which cover layer 300 is not provided. In that case, the generation and deposition of combustion residues on the covering layer 300 can be eliminated even more reliably while eliminating the slip of the PM through the partition walls 30 in the portions where the covering layer 300 is not provided.
    [071] In the first to third working examples described above, cases were explained in which the thickness of the cover layer 300 is substantially constant in the flow direction of the discharge gas, but the upstream thickness can be set to be greater than than the downstream thickness. For example, the thickness of the cover layer 300 can be set to gradually decrease from the upstream side to the downstream side, as illustrated in Figure 11.
    [072] The PM in the exhaust gas is more easily trapped at locations in the cover layer 300 that are near the upstream end than at locations far from it. In this way, most of the PM in the exhaust gas can get trapped even if the thickness of the cover layer 300 decreases from the upstream side to the downstream side. Additionally, the pressure loss is less when the thickness of the cover layer 300 on the downstream side is less. This makes it possible to keep the increases in pressure loss caused by the covering layer 300 to a minimum.
    [073] In the first to third working examples described above, cases were explained, in which the covering layer 300 is provided only in the dividing walls 30 surrounding the second passages 5, but the covering layer 300 can also be provided in the dividing walls 30 enclosing the first passages 4. However, the pressure loss in the particulate filter 1 can significantly increase when the covering layer 300 is provided on both partition walls 30 enclosing the second passages 5 and the walls of partition 30 enclosing the first passes 4. In this way, cover layer 300 can be provided on both partition walls 30, provided that the pressure drop in particulate filter 1 is within a permissible range. 1 particle filter 2 housing 3 base material 4 first passes 5 second pass 30 partition wall 40 buffer 50 buffer 300 cover layer 301 particle 302 span 303 particle 310 catalyst cover layer 311 pore
    权利要求:
    Claims (5)
    [0001]
    1. Particle filter (1), CHARACTERIZED by the fact that it comprises: a plurality of first passages (4), the ends of the first passages (4) being blocked on an upstream side in the flow direction of the exhaust gas, a plurality of second passages (5), the ends of the second passages (5) being blocked on a side downstream in the flow direction of the discharge gas, porous dividing walls (30) which are elements separating the first passages (4) of the second passages (5), the porous partition walls (30) having pores of a size such that combustion residues pass through the pores and a porous covering layer (300) provided in part of a region of the partition walls ( 30), from an upstream end of the partition walls (30) to a position before a downstream end of the partition walls (30), the porous cover layer having pores smaller than the pores of the partition walls (30 ) and the thickness of the cover layer ure (300) gradually decreasing from the upstream side of the cover layer (300) to the downstream side of the cover layer (300).
    [0002]
    2. Particle filter (1), according to claim 1, CHARACTERIZED by the fact that a catalyst (310) having oxidation capacity is supported in a region of the dividing walls (30), in which the covering layer ( 300) is not provided.
    [0003]
    3. Particle filter (1), according to claim 1 or 2, CHARACTERIZED by the fact that the porous partition walls (30) have pores, whose average pore size varies from 25 μm to 50 μm.
    [0004]
    4. Particle filter (1) according to any one of claims 1 to 3, CHARACTERIZED by the fact that the porous cover layer (300) is a dispersion, the dispersion being composed of particles having a varying average particle size from 1 µm to 10 µm.
    [0005]
    5. Particle filter (1), according to any one of claims 1 to 4, CHARACTERIZED by the fact that the porous cover layer (300) comprises a metal, whose ionization tendency is greater than that of a main component combustion residues.
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    同族专利:
    公开号 | 公开日
    EP2832962A1|2015-02-04|
    US20150059321A1|2015-03-05|
    IN2014DN08076A|2015-05-01|
    EP2832962B1|2016-08-17|
    KR20140131964A|2014-11-14|
    CN104204433A|2014-12-10|
    EP2832962A4|2015-05-20|
    CN104204433B|2016-08-31|
    AU2012374854A1|2014-10-16|
    AU2012374854B2|2016-05-12|
    WO2013145266A1|2013-10-03|
    US9394816B2|2016-07-19|
    JP5787031B2|2015-09-30|
    JPWO2013145266A1|2015-08-03|
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    法律状态:
    2018-12-18| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2020-02-04| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-02-17| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-05-04| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 30/03/2012, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    PCT/JP2012/058620|WO2013145266A1|2012-03-30|2012-03-30|Particulate filter|
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