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US20080209893A1 - Exhaust aftertreatment system having a diesel particulate filter manufactured for reducing thermal gradients - Google Patents

Exhaust aftertreatment system having a diesel particulate filter manufactured for reducing thermal gradients Download PDF

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Publication number
US20080209893A1
US20080209893A1 US11/712,615 US71261507A US2008209893A1 US 20080209893 A1 US20080209893 A1 US 20080209893A1 US 71261507 A US71261507 A US 71261507A US 2008209893 A1 US2008209893 A1 US 2008209893A1
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US
United States
Prior art keywords
skin layer
honeycomb structure
heat capacity
less
cell walls
Prior art date
Legal status (The legal status 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 status listed.)
Abandoned
Application number
US11/712,615
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English (en)
Inventor
James J. Driscoll
James R. Weber
Maarten Verkiel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar Inc
Original Assignee
Caterpillar Inc
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Filing date
Publication date
Application filed by Caterpillar Inc filed Critical Caterpillar Inc
Priority to US11/712,615 priority Critical patent/US20080209893A1/en
Assigned to CATERPILLAR INC. reassignment CATERPILLAR INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: VERKIEL, MAARTEN, DRISCOLL, JAMES J., WEBER, JAMES R.
Priority to PCT/US2008/002589 priority patent/WO2008106165A1/fr
Publication of US20080209893A1 publication Critical patent/US20080209893A1/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/16—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay
    • C04B35/18—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silicates other than clay rich in aluminium oxide
    • C04B35/195—Alkaline earth aluminosilicates, e.g. cordierite or anorthite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2425—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material
    • B01D46/2429—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material of the honeycomb walls or cells
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2425—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material
    • B01D46/2444—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material of the outer peripheral sealing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2425—Honeycomb filters characterized by parameters related to the physical properties of the honeycomb structure material
    • B01D46/24494—Thermal expansion coefficient, heat capacity or thermal conductivity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
    • B01D46/2459—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure of the plugs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
    • B01D46/2462—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure the outer peripheral sealing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
    • B01D46/2482—Thickness, height, width, length or diameter
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/66—Regeneration of the filtering material or filter elements inside the filter
    • B01D46/80—Chemical processes for the removal of the retained particles, e.g. by burning
    • B01D46/84—Chemical processes for the removal of the retained particles, e.g. by burning by heating only
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0006—Honeycomb structures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust 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
    • F01N3/022—Exhaust 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
    • F01N3/0222—Exhaust 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2279/00—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses
    • B01D2279/30—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses for treatment of exhaust gases from IC Engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
    • B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
    • B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
    • B01D46/2418—Honeycomb filters
    • B01D46/2498—The honeycomb filter being defined by mathematical relationships
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/34—Non-shrinking or non-cracking materials
    • C04B2111/343—Crack resistant materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2330/00—Structure of catalyst support or particle filter
    • F01N2330/06—Ceramic, e.g. monoliths
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present disclosure relates generally to reducing thermal gradients in an exhaust aftertreatment system, and more particularly to reducing thermal gradients between a honeycomb structure and a skin layer of a diesel particulate filter during a regeneration process.
  • DPF diesel particulate filter
  • a DPF generally consists of a ceramic honeycomb structure that is surrounded by a non-permeable skin layer and includes numerous channels that are blocked at alternate ends. This structure forces exhaust gas to flow through the porous walls between the channels, leaving particulate matter deposited on the walls. Periodically, or once a substantial amount of particulate matter is collected within the DPF, it must be cleaned out to prevent blockage. The process of removing the accumulated particulate matter from the DPF is referred to generally as regeneration.
  • a common method includes quickly heating the particulate matter to a temperature at which it combusts. This involves heating the exhaust gas, and as a result, the DPF, to very high temperatures. Since the skin layer of the DPF is more dense than the porous walls of the honeycomb structure, it has a much higher heat capacity. During the regeneration process the porous walls heat up much more rapidly than the skin layer and create large thermal gradients. The stress caused by these large thermal gradients may result in the formation of cracks in the DPF. Ultimately, these cracks may lead to failure of the DPF.
  • U.S. Pat. No. 7,073,327 teaches a diesel particulate filter having a reduced temperature gradient during a regeneration process. Specifically, partition walls defining cells of the filter have an increased wall thickness, and a cell density of the filter is increased. Setting the thickness and density to appropriate values provides a reduced temperature gradient in the filter. This reference does not, however, contemplate a temperature gradient between a honeycomb structure of the filter and a skin layer surrounding the filter.
  • the present disclosure is directed to one or more of the problems set forth above.
  • a method of regenerating a diesel particulate filter includes a step of oxidizing particulate matter trapped within the honeycomb structure by heating at least a portion of the honeycomb structure.
  • a thermal gradient between the honeycomb structure and the skin layer is limited to less than a crack causing thermal gradient.
  • the limiting step includes at least one of maintaining a ratio of a heat capacity of the skin layer to a heat capacity of the cell walls at less than about 5, blocking at least those passages comprising a perimeter of the honeycomb structure, and heating the skin layer from an external side.
  • an exhaust aftertreatment system in another aspect, includes a can having a gas inlet and a gas outlet.
  • the exhaust aftertreatment system also includes a substrate having a honeycomb structure and a skin layer surrounding the honeycomb structure disposed within the can.
  • the honeycomb structure comprises a plurality of elongated cell walls extending from the gas inlet to the gas outlet and defining a plurality of passages, wherein the cell walls are permeable relative to the skin layer.
  • the exhaust aftertreatment system further includes means for limiting a thermal gradient between the honeycomb structure and the skin layer to less than a crack causing thermal gradient during a regeneration process.
  • the limiting means include at least one of means for maintaining a ratio of a heat capacity of the skin layer to a heat capacity of the cell walls at less than about 5, means for blocking at least those passages comprising a perimeter of the honeycomb structure, and means for heating the skin layer from an external side.
  • a diesel particulate filter in still another aspect, includes a honeycomb structure having a plurality of elongated cell walls defining a plurality of passages and a skin layer surrounding the honeycomb structure.
  • the diesel particulate filter also includes at least one crack avoidance feature of: the skin layer having a heat capacity less than about five times the heat capacity of the cell walls and at least those passages comprising a perimeter of the honeycomb structure being blocked.
  • the crack avoidance feature limits a thermal gradient between the honeycomb structure and the skin layer to less than a crack causing thermal gradient.
  • FIG. 1 is a perspective diagrammatic view of a diesel particulate filter according to the present disclosure
  • FIG. 2 is a top diagrammatic view of one embodiment of the diesel particulate filter of FIG. 1 according to the present disclosure
  • FIG. 3 is a top diagrammatic view of another embodiment of the diesel particulate filter of FIG. 1 according to the present disclosure
  • FIG. 4 is a top diagrammatic view of yet another embodiment of the diesel particulate filter of FIG. 1 according to the present disclosure
  • FIG. 5 is a graph of thermal gradient versus skin thickness according to the embodiment of FIG. 2 ;
  • FIG. 6 is a graph of thermal gradient versus number of cells blocked according to the embodiment of FIG. 4 .
  • DPF 10 includes a can 12 having a gas inlet 14 and a gas outlet 16 .
  • a honeycomb structure 18 is disposed within the can 12 and includes a plurality of elongated, permeable cell walls 20 extending from the gas inlet 14 to the gas outlet 16 .
  • the honeycomb structure 18 may be composed of a ceramic material, such as, for example, cordierite or porcelain.
  • the cell walls of the honeycomb structure 18 are uniformly thin and define a plurality of passages that are blocked at alternate ends, in a checkerboard fashion.
  • a passage 22 is blocked at the gas inlet 14 .
  • a passage 24 is not blocked at the gas inlet 14 and is, therefore, blocked at the gas outlet 16 .
  • the passages may comprise a square shape, as shown, or may comprise any other geometric shape.
  • FIG. 2 a top view of one embodiment of DPF 10 is shown.
  • the view of FIG. 2 may be of either the gas inlet 14 or the gas outlet 16 (both of FIG. 1 ) of the DPF 10 .
  • the DPF 10 is provided with a skin layer 30 interconnected with and extending continuously around the honeycomb structure 18 .
  • the skin layer 30 provides structural stability to the honeycomb structure and may also comprise a ceramic material, or any other suitable material, and may be non-permeable relative to the cell walls.
  • a mat layer 32 may be provided between the can 12 and the skin layer 30 to cushion the honeycomb structure 18 against shock and vibration.
  • the mat layer 32 occupies space between the honeycomb structure 18 and the surrounding can 12 and may also serve to insulate against heat loss from the honeycomb structure.
  • a thickness of the skin layer 30 is selected to maintain a ratio of a heat capacity of the skin layer to a heat capacity of the cell walls 20 at less than about 5. Preferably, that ratio is maintained at less than about 2.5.
  • “about” indicates rounding to one significant digit. For example, 10.4 is about 10, 2.54 is about 2.5, etc.
  • FIG. 3 shows a top view of a second embodiment of DPF 10 .
  • at least those passages comprising a perimeter of the honeycomb structure 18 such as, for example, passages 40 , 42 , and 44 , are blocked. Blocking may occur at the gas inlet 14 ( FIG. 1 ), gas outlet 16 ( FIG. 1 ), or both and may be achieved by masking or filling the passages.
  • a single row of passages extending around the perimeter of the honeycomb structure 18 may be blocked. Alternatively, two, three, or more rows around the perimeter of the honeycomb structure 18 may be blocked.
  • a heating layer 50 may be provided around the skin layer 30 .
  • the heating layer 50 may be formed of any substance useful for generating or conducting heat.
  • heater 50 may be a thin film electric resistance heater of a type known in the art.
  • a heater (not shown) may be provided external to the mat 32 and or can 12 .
  • a DPF 10 generally consists of a ceramic honeycomb structure 18 that is surrounded by a non-permeable skin layer 30 and includes numerous channels, such as, for example, channels 22 and 24 , that are blocked at alternate ends. This structure forces exhaust gas to flow through the porous walls between the channels, leaving particulate matter deposited on cell walls 20 . Once a large amount of particulate matter is collected within the DPF 10 , it must be cleaned out to prevent blockage. The process of removing the accumulated soot or particulate matter from the DPF 10 is referred to generally as regeneration.
  • a common method of regeneration includes quickly heating the particulate matter to a temperature at which it combusts. This involves heating the exhaust gas, and as a result, the DPF 10 , to very high temperatures. Since the skin layer 30 of the DPF 10 is more dense than the porous cell walls 20 of the honeycomb structure, it has a much higher heat capacity. During the regeneration process the porous cell walls 20 heat up much more rapidly than the skin layer 30 and create large thermal gradients. The stress caused by these large thermal gradients may result in the formation of cracks in the DPF 10 . These thermal gradients may also be referred to as “crack causing thermal gradients.” Ultimately, these cracks may lead to failure of the DPF 10 .
  • Utilizing one or more of the diesel particulate filter embodiments of the present disclosure maintains a thermal gradient between the cell walls and the skin layer below the crack causing thermal gradient.
  • the DPF of FIG. 2 provides a skin layer thickness that maintains the heat capacity ratio of the skin layer 30 to the cell walls 20 at less than about 2.5. If the cell walls 20 are about 0.3 mm thick and about 50% porous, providing a skin layer thickness of about 0.5 maintains the heat capacity ratio at less than about 2.5.
  • FIG. 5 is a graph 60 of thermal gradient 62 , shown on the vertical axis, versus skin thickness 64 , shown on the horizontal axis, according to the embodiment of FIG. 2 .
  • Depicted on the graph 60 is a sample gradient 66 showing thermal gradients between the honeycomb structure 18 and skin layer 30 for various thickness values of the skin layer.
  • a thermal gradient between about 500° C./cm and 600° C./cm may be a crack causing thermal gradient, it can be seen that maintaining a skin layer thickness below about 1.5 mm may be desired. It may be further desirable to maintain a thickness of the skin layer 30 at about 0.5 mm.
  • the DPF 10 of FIG. 3 provides for blocking at least those cell passages comprising a perimeter of the honeycomb structure 18 . Namely, one or more rows of cell passages along the exterior of the honeycomb structure 18 may be plugged. Blocking these cell passages reduces the heat transfer that is passed to these peripheral cells, and, therefore, the crack causing thermal gradients between the cell walls 20 and the skin layer 30 .
  • FIG. 6 is a graph 70 of thermal gradient 72 , shown on the vertical axis, versus number of cells blocked 74 , shown on the horizontal axis, according to the embodiment of FIG. 3 .
  • Depicted on the graph 70 is a sample gradient 76 showing thermal gradients between the honeycomb structure 18 and skin layer 30 for various numbers of cell rows blocked. Since it may be desirable to maintain the thermal gradient during regeneration to below between about 500° C./cm and 600° C./cm, it may be desirable to block at least one to two rows of cells along the periphery of the honeycomb structure.
  • the DPF of FIG. 4 provides a heating layer 50 external to the skin layer 18 .
  • Heating the skin layer 30 externally helps compensate for the large difference in heat capacity between the skin layer 30 and the honeycomb structure 18 . Reducing the heat gradient between the two layers during the regeneration process helps prevent occurrence of a crack causing thermal gradient.
  • a skin layer 30 of a desired thickness may be provided on a honeycomb structure 18 having at least those cell passages comprising a perimeter of the honeycomb being blocked.
  • a skin layer 30 may be set to a desired thickness of a DPF 10 that includes a heater provided external the skin layer.

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  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Ceramic Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
  • Processes For Solid Components From Exhaust (AREA)
US11/712,615 2007-03-01 2007-03-01 Exhaust aftertreatment system having a diesel particulate filter manufactured for reducing thermal gradients Abandoned US20080209893A1 (en)

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US11/712,615 US20080209893A1 (en) 2007-03-01 2007-03-01 Exhaust aftertreatment system having a diesel particulate filter manufactured for reducing thermal gradients
PCT/US2008/002589 WO2008106165A1 (fr) 2007-03-01 2008-02-27 Système de post-traitement d'échappement doté d'un filtre à particules diesel fabriqué pour réduire les gradients thermiques

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US11/712,615 US20080209893A1 (en) 2007-03-01 2007-03-01 Exhaust aftertreatment system having a diesel particulate filter manufactured for reducing thermal gradients

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JP2023135121A (ja) * 2022-03-15 2023-09-28 日野自動車株式会社 フィルタ

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