Abstract: The present invention provides a filter medium causing a low pressure drop. The present invention is a filter medium including a porous fluororesin membrane and an air-permeable support member laminated on at least one surface of the porous fluororesin membrane. In this filter medium, the air-permeable support member is a blended nonwoven fabric containing: core-sheath fibers (A) having a polyester core and a polyolefin sheath; polyester fibers (B); and core-sheath fibers (C) having a polyester core and a copolymerized polyester sheath.

Abstract: An exhaust gas purification system with which diesel particulate filter (“DPF”) regeneration can be continued even when deceleration occurs during the DPF regeneration. The system includes a regeneration deceleration period intake/exhaust control unit that, when a vehicle decelerates during the DPF regeneration, increases an exhaust gas flow rate through an exhaust pipe by controlling respective openings of an exhaust gas recirculation (“EGR”) device and an intake throttle and adjusting a turbocharging amount of a high pressure stage turbocharger.

Abstract: A porous membrane, comprising a blend of a first powder of metal particles of the first average size and a second powder of metal particles of a second average size, the first powder and the second powder sintered together. The first average size is five to fifty times greater than the second average size. The porous membrane comprises from 40% to 60% by weight of the first powder.

Abstract: A exhaust gas purification device is structured such that it is possible to improve an assembling work ability or a maintenance work ability of gas purifying bodies or exhaust gas purifying cases. In an exhaust gas purification device provided with gas purifying bodies which purify an exhaust gas discharged by an engine, and a gas purifying housing which is provided with the gas purifying bodies therein, the exhaust gas purification device is structured such that a support bracket which supports the gas purifying housing is provided, a bolt hole is formed in the support bracket, an insertion guide is formed in the support bracket, and an attaching bolt is engaged with and disengaged from the bolt hole via the insertion guide.

Abstract: A filter element is disclosed made from a gathered paper web that may be crimped, embossed, and/or corrugated. In accordance with the present disclosure, the paper web is treated with at least two different additives. The first additive comprises amphiphilic molecules, having hydrophilic and hydrophobic ends such as a ketene dimer that has one or more branching groups. The second additive, on the other hand, may comprise a polymer component such as a polyalkylene glycol. The filter element may also be treated with a polyamine or an amino acid or salt thereof. In one embodiment, the filter element may be incorporated into the filter of a smoking article. The two additives together may improve smoke taste, reduce some smoke phenols, and reduce some smoke carbonyls.

Abstract: The present invention relates to device and method for reducing soot particles. The device for reducing soot particles includes a first filter provided to an exhaust gas flow passage through which exhaust gas from a diesel engine flows to have a predetermined volume of a plurality of grains to be operated as a volumetric filtration system, and a second filter provided to a predetermined position of the second filter to be operated as a surface filtration system.

Abstract: A method and apparatus are provided for separating droplets of finely aerosolized elemental mercury from a fluid stream in which the droplets are dispersed, particularly a gaseous stream. In the method, a precious metal wire capillary surface or precious metal-coated wire capillary surface is contacted with the gaseous stream, causing the aerosolized droplets to deposit on the capillary surface and by capillary action to coalesce with other of such droplets. The surface is oriented to allow the mercury to flow by gravitational forces and capillary action to the lowermost portions of the surface, where it accumulates and can be collected. Metallic capillary surfaces comprised of finely braided strands of silver, gold, palladium, platinum, or rhodium wire, or wire coated with one or more of these metals, are particularly preferred.

Abstract: A method for engine-out soot flow rate prediction of an exhaust gas treatment system is provided. A measured level of oxides of nitrogen in the exhaust gas treatment system is received. An engine fuel injection timing and air-fuel ratio of an engine producing the oxides of nitrogen are also received. An engine timing factor is determined based on the engine fuel injection timing. An engine air-fuel ratio factor is determined based on the engine air-fuel ratio. An engine-out soot flow rate prediction is generated based on the measured level of oxides of nitrogen, the engine timing factor, and the engine air-fuel ratio factor.

Abstract: A honeycomb structure includes periphery honeycomb fired bodies which include at least a single piece of a periphery small honeycomb fired body having in the cross-section a cross-sectional area which is less than about 60% of a cross-sectional area of a single piece of the center-portion honeycomb fired body. A cross-sectional area of a periphery honeycomb bonded body in the cross-section is about 60% or more of the cross-sectional area of a single piece of the center-portion honeycomb fired body. The second adhesive layer is provided between the periphery small honeycomb fired body and the at least one piece of the honeycomb fired body. The second adhesive layer has thermal conductivity higher than thermal conductivity of a first adhesive layer. The second adhesive layer has Young's modulus higher than Young's modulus of the first adhesive layer. The center-portion honeycomb fired bodies are bonded together with the first adhesive layer.

Abstract: A ceramic honeycomb structure suitable for particulate filters, having an inlet face and an outlet face, comprising a plurality of inlet cells and a plurality of outlet cells extending through the structure from the inlet face to the outlet face, the inlet cells being open at the inlet face and closed where adjoining the outlet face, and the outlet cells being open at the outlet face and closed where adjoining the inlet face. The inlet and/or outlet cells are quadrangular in cross-section and are arranged in an alternating pattern; the outlet cells may have a cross-sectional area generally smaller than that of inlet cells and no point of a given inlet cell is closer to an adjacent inlet cell than to an adjacent outlet cell. A process for preparing the ceramic honeycomb structure is also disclosed.

Abstract: A device for at least one self-heated and dense ceramic tube for gas separation. The device includes at least one dense ceramic tube in an environment accessible to a mixture of gases, the at least one tube acting as a diffusion membrane for separating at least one gas from the mixture of gases. Two electrical contacts are provided which allow connecting a power supply to the ceramic tube and driving an electric current through the ceramic tube. The contacts can be in the farm of short coils wrapped around the ceramic tube at difference places. When a voltage is applied to the contacts, an electrical current flows from one contact to the other through the ceramic tube. The current in the ceramic tube heats the tube. Thus, the tubes heat themselves. The hot tube allows separating a gas from the mixture of gases. The driving force for the diffusion is achieved by a pressure difference generated by pumping at the side of the separated gas and pressing at the side of the mixture of gases.

Abstract: An object of the present invention is to detect any breakdown or failure of a particulate filter more appropriately. A failure detecting apparatus for detecting failure of a particulate filter according to the present invention comprises an acquiring section which acquires an amount of PM contained in an exhaust gas allowed to outflow from the particulate filter; a regeneration process executing section which executes a filter regeneration process for oxidizing and removing PM deposited in the particulate filter; and a failure judging section which judges that the particulate filter is in the failure state if a decreased amount of the amount of PM contained in the exhaust gas acquired by the acquiring section, during a predetermined period of time as started from a point in time at which the execution of the filter regeneration process performed by the regeneration process executing section is completed, is not equal to or larger than a predetermined reference amount.

Abstract: An exhaust gas treatment system for an internal combustion engine is provided comprising an exhaust gas conduit, a particulate filter (“PF”) device, a hydrocarbon source and an electronic control module including operative logic which when implemented. The PF has a filter structure for removal of particulates in the exhaust gas and is selectively regenerated based on an amount of particulates trapped within the filter structure of the PF device. The control module is in communication with the internal combustion engine and the hydrocarbon source, and receives a regeneration signal indicating the amount of particulates trapped within the filter structure of the PF device. The electronic control module includes control logic for monitoring the internal combustion engine prior to a regeneration event. The electronic control module includes control logic for determining a plurality operating parameters of the internal combustion engine based on the monitoring.

Abstract: An oil coalescing filter may be used in an oil separator tank with an industrial sized compressor/vacuum package, like a rotary screw compressor/vacuum or a liquid ring compressor/vacuum. The oil coalescing filter has filter media including: a first fiber media adapted for continuously removing oil; and a second fiber media adapted for final oil coalescing; the first fiber media having a greater basis weight than said second fiber media.

Abstract: The present invention aims to provide a honeycomb structure capable of preventing a plugging failure and forming cracks by heat shock which are caused by a cell having a small cross-section.

Abstract: The present invention is intended to detect a failure of a PM filter with a higher degree of accuracy. The present invention is provided with: a PM trapping efficiency calculation part to calculate a PM trapping efficiency (which is a proportion of an amount of particulate matter trapped with respect to an amount of inflow particulate matter) based on an amount of inflow particulate matter obtained by an inflow particulate matter obtaining part, and an amount of outflow particulate matter detected by a PM sensor; and a failure detection part to make a determination that a failure has occurred in the PM filter, in cases where there has appeared a tendency for the PM trapping efficiency to decrease during a period of time until the execution of the following filter regeneration processing is started after the completion of execution of the filter regeneration processing.

Abstract: A particulate matter detecting apparatus for an internal combustion engine that can estimate a discharge amount of the particulate matter accurately. The particulate matter detecting apparatus for an internal combustion engine, comprises: a sensor disposed at an exhaust passage of the internal combustion engine, the sensor including a pair of electrodes for detecting particulate matter in an exhaust gas; means for estimating a discharge amount of the particulate matter based on an output of the sensor, and means for acquiring a predetermined parameter that serves as an index for a rate with which the particulate matter in the exhaust gas is deposited on the sensor. The discharge amount estimating means corrects an estimated value of the discharge amount of the particulate matter based on the parameter acquired by the parameter acquiring means.

Abstract: A filtration media with improved filtration, strength, tear resistance and air permeability in the form of a relatively thin and lightweight wet-laid fibrous web that has a wet Mullen ratio of 60% to 75% to ensure that the media is flexible enough to be formed into a fluted structure, and strong enough to retain the fluted structure when wound into a roll and to permit further processing without the media becoming too brittle. The filtration media comprises a blend of cellulose and synthetic fibers having a basis weight of 81% to 87% of a basis weight of the media and a resin binder having a basis weight of 13% to 19% (preferably about 16%) of the basis weight of the media.

Abstract: Fiber structures and methods are described that incorporate a body of a micron fiber modified by the attachment of discrete length, crimped nano-fibers. Numerous of these modified fiber structures can be assembled into air filter media. Further augmentations of the modified fibers and media can be implemented to improve filtration characteristics.

Abstract: Inner cases are connected to outer cases through joining flanges which protrude toward outer peripheries of the outer cases. A plurality of combinations each including filters, the inner cases, and the outer cases are provided. Both the joining flanges are sandwiched and fixed between a pair of sandwiching flanges, thereby connecting the plurality of outer cases to each other.

Abstract: A ceramic honeycomb filter comprising a ceramic honeycomb structure having large numbers of flow paths partitioned by porous cell walls, and plugs disposed in the flow paths alternately on the exhaust gas inlet or outlet side, to remove particulate matter from an exhaust gas passing through the porous cell walls; the porous cell walls having porosity of 45-75%, the median pore diameter A (?m) of the cell walls measured by mercury porosimetry, and the median pore diameter B (?m) of the cell walls measured by a bubble point method meeting the formula of 35<(A?B)/B×100?70, and the maximum pore diameter of the cell walls measured by a bubble point method being 100 ?m or less.

Abstract: A thin-walled porous ceramic wall-flow filter is disclosed. The filter produces a relatively lower pressure drop coupled with relatively high initial filtration efficiency (FE0), and may enable packaging the filter in a smaller volume. The filter includes a plurality of porous ceramic walls forming cell channels. At least some of the cells are plugged forcing some exhaust gases through the walls, thereby filtering out entrained particulates. The walls have a wall thickness (Twall) wherein 102 ?m?Twall<279 ?m, and a median pore diameter (MPD), and wherein 10<Twall/MPD, and may also be <40. The relatively small median pore diameter (MPD) in comparison to the wall thickness (Twall) allows the use of thinner ceramic walls that provide less flow resistance than thicker walls while maintaining sufficient initial filtration efficiency (FE0). Furthermore, such thin-walled filter structure coupled with unequal inlet/outlet area ratio (Ai/Ao) may allow filter lengths to be additionally shortened.

Abstract: A multi-layered filter web having at least one at least one filter layer bonded to at least one additional filter layer. The filter layers are bonded together by at least one of ultrasonically and matted. The bonding is in at least one of at least one knurled edge region and in at least one matting region.

Abstract: Exhaust systems and components are suitable for use with gasoline engines to capture particulates and to reduce gaseous emissions, where three-way conversion (TWC) catalysts located on a particulate filters are provided. Coated particle filters having washcoat loadings in the range of 1 to 4 g/ft3 result in minimal impact on back pressure while simultaneously providing TWC catalytic activity and particle trapping functionality to meet increasingly stringent regulations such as Euro 6. Sufficient to high levels of oxygen storage components (OSC) are also delivered on and/or within the filter. The filters can have a coated porosity that is substantially the same as its uncoated porosity. The TWC catalytic material can comprise a particle size distribution such that a first set of particles has a first d90 particle size of 7.5 ?m or less and a second set of particles has a second d90 particle size of more than 7.5 ?m.

Abstract: There is provided a honeycomb structure including a honeycomb base material including a porous partition wall parent material; plugged portions; and a porous collecting layer disposed on the surface of the partition wall parent material in the remaining cells. A melting point of a material constituting the collecting layer is higher than that of a material constituting the partition wall parent material, a pore surface area per unit volume of the collecting layer is 2.0 times or more a pore surface area per unit volume of the partition wall parent material, and a thickness of a portion of the collecting layer which penetrates into pores of the partition wall parent material is 6% or smaller of that of each of partition walls including the partition wall parent material and the collecting layer.

Abstract: An exhaust gas emission control system includes a cylindrical inflow body and an inflow pipe into which exhaust gas flows. The exhaust gas emission control system also includes a cylindrical outflow body and an outflow pipe from which the exhaust gas flows. The inflow pipe is provided with a louver member that covers an opening of the inflow body near an upstream side of an exhaust gas flow direction. The louver member is provided with slits and inclined plates capable of changing a flow direction of the exhaust gas passing through the slits into a desired direction.

Abstract: A system for treating diesel exhaust is disclosed. The system includes a first filter including layers of filtration material positioned between layers of corrugated metallic foil. The metallic foil defines a honeycomb arrangement of longitudinal passageways from an upstream end to a downstream end and also openings for allowing exhaust to pass between adjacent longitudinal passageways of the metallic foil. The filtration material is positioned such that exhaust between the adjacent longitudinal passageways passes through the filtration material. The metallic foil also includes flow diverting structures to divert flow within the longitudinal passageways through the openings. A second filter is positioned downstream from the first filter. The second filter defines a honeycomb arrangement of longitudinal passageways. The longitudinal passages are selectively plugged adjacent upstream and downstream ends to force flow radially through walls between the longitudinal passages of the second filter.

Abstract: Distribution of a precoat agent is made uniform in a target gas directing to a filter. To this end, an intake opening of a filter device is formed as a slit-like or rectangular opening extending in a width direction. An accumulation recess is formed in an upper edge portion of the intake opening to have a profile that opens downward as viewed from a longitudinal direction of the intake opening. The accumulation recess is continuously formed in the longitudinal direction of the intake opening. A precoat agent nozzle is provided in a longitudinal predetermined position of the intake opening for ejecting the precoat agent and carrier gas toward an inner depth surface of the accumulation recess.

Abstract: An exhaust gas aftertreatment system for an engine can perform manual regeneration control for regenerating a particulate removal filter by increasing the engine rotation speed. The system can suppress the engine rotation speed increase while maintaining the exhaust gas temperature required to regenerate the particulate removal filter. The system can set the target engine rotation speed to a first set value when a regeneration instruction signal from a manual regeneration switch is received. When, although the engine rotation speed falls within a predetermined engine rotation speed range including the first set value that is the target engine rotation speed for a predetermined time period, the exhaust gas temperature does not reach the filter's regeneration temperature within the predetermined time period, the target engine rotation speed is repeatedly reset by being increased from the first set value by a predetermined rotation speed.

Abstract: A method for cleaning and checking a particle filter of a motor vehicle is provided. In a first step soot particles which have collected in the particle filter are burnt off. In a second step ash located in the particle filter is blown out using compressed air. A cleaning device for a particle filter of a motor vehicle is also provided.

Abstract: The fiber webs described herein may be incorporated into filter media and filter elements. The fiber webs may exhibit a high dust holding capacity. The fiber webs may also exhibit a low thickness. The fiber webs may be sufficiently flexible and/or deformable so that they may be processed to include a series of waves (also known as flutes) that extend along the cross-machine direction.

Abstract: The invention relates to diesel soot particulate filter cartridge having a central filter cartridge axis. The filter cartridge has a radial flow. The filter cartridge comprises a porous structure. The porous structure is coiled around the central filter cartridge axis. The porous structure comprises non-sintered metal fibers, said fibers having a roughness being higher than 1.7. The invention further relates to a method of manufacturing a diesel soot particulate filter cartridge. Furthermore the invention relates to a multicartridge diesel soot particulate filter. The flow through the multicartridge diesel soot particulate filter is axial while the flow through the filter cartridges is radial.

Abstract: Dehumidifiers having improved heat exchange blocks and associated methods of use and manufacture are disclosed. A heat exchange system in accordance with a particular embodiment can include a plurality of elements with a plurality of airflow channels. A plurality of peripheral spacers are positioned toward edges of neighboring elements and extend in a first direction. A first airflow path extends in the first direction, and is at least partially defined by the corresponding elements and the peripheral spacers. A second airflow path is defined by the airflow channels and extends in a second direction, and an airflow blocker is positioned at a corner portion of the elements to prevent fluid communication between the first and the second airflow paths at the elements. In certain embodiments, the heat exchange system can further include a dehumidifier having an evaporator positioned between the first and second airflow paths.

Abstract: An apparatus and method for a tactile air filter including a filter media composed primarily of glass fibers having a softening finish applied thereto.

Abstract: The invention relates to a multi-layer cleanable filter material for gas and liquid filtration, said filter material comprising a filter layer and a substrate layer that follows the filter layer in the flow direction, wherein the filter layer is substantially dendrite-free and consists of a melt-blown fleece made of elastic polymer fibres that has a breaking elongation of at least 100%.

Abstract: A method of removing ash from a wall flow type particulate filter which is arranged in an exhaust passage of an internal combustion engine in which combustion is performed in an excess of oxygen for trapping particulate matter in exhaust gas, using a solid acid which is carried on the particulate filter, renders the state of the particulate filter a state where the exhaust gas which flows into the particulate filter is lowered in concentration of oxygen and the particulate filter is raised in temperature, and then renders the state of the particulate filter a state where the exhaust gas which flows into the particulate filter in an oxidizing atmosphere contains SOx.

Abstract: Cellular ceramic articles are manufactured from a green cellular ceramic body that includes a binder material and a plurality of channels. At least one of the channels is coated with a slurry that includes a green coating composition and a solvent to form a coating layer. The binder material is insoluble in the solvent.

Abstract: The fiber webs described herein may be incorporated into filter media and filter elements. The fiber webs may exhibit a high dust holding capacity. The fiber webs may also exhibit a low thickness. The fiber webs may be sufficiently flexible and/or deformable so that they may be processed to include a series of waves (also known as flutes) that extend along the cross-machine direction.

Abstract: The fiber webs described herein may be incorporated into filter media and filter elements. The fiber webs may exhibit a high dust holding capacity. The fiber webs may also exhibit a low thickness. The fiber webs may be sufficiently flexible and/or deformable so that they may be processed to include a series of waves (also known as flutes) that extend along the cross-machine direction.

Abstract: In an exhaust gas treatment device provided with: an exhaust gas treatment unit in which an oxygen combustion boiler 1 using coal as fuel, a denitration device 3, an air preheater 4, a dust-collection device 5, a desulfurization device 6, and a carbon dioxide recovery device 8 are sequentially arranged from the upstream side to the downstream side of an exhaust gas duct; and an exhaust gas circulation unit which branches off from the exhaust gas duct at an outlet of the dust-collection device 5 or an outlet of the desulfurization device 6 and through which the exhaust gas is preheated by the air preheater 4 and returned to the oxygen combustion boiler 1, a heat-recovery heat exchanger 13 that adjusts a gas temperature at an inlet of the dust-collection device 5 to be not greater than an acid dew point of SO3 and not lower than a water dew point is provided between the air preheater 4 and the dust-collection device 5, a reheating heat exchanger 13 that adjusts a gas temperature to be not lower than the acid de

Abstract: A structure for collecting liquid droplets from an aerosol can have a structure and properties that are selected for efficient liquid collection. In particular, the strand radius and spacing of a mesh, and a material for coating the mesh, can be selected to provide efficient collection of water droplets from fog.

Abstract: A polar cap for a vacuum waste tank includes an annulus with a lower outer mounting flange and an upper inner mounting flange surrounding a separator opening configured to be coupled to a separator; an inlet opening disposed in the annulus configured to be coupled to a waste line; and another opening disposed in the annulus configured to be coupled to a sensor or a rinse nozzle. The cap can carry sensors, rinse nozzles, inlets, and diverts.

Abstract: A honeycomb filter includes a honeycomb base material, plugged portions, and a porous collecting layer disposed on the surface of the partition wall parent material in at least the remaining cells. The collecting layer has a constitution in which a plurality of particles combine or intertwine with one another, and the collecting layer includes fibrous fiber particles as the plurality of particles, and includes the particles having an average fiber diameter of 0.1 to 15 ?m and an average aspect ratio of 3 or larger. An open area ratio of the surface of the collecting layer is 20% or larger.

Abstract: The disclosed exhaust treatment device for a diesel engine can prevent heat damage to a DPF when regenerating said DPF. If a selection device (7), which selects whether to allow or prohibit an automatic DPF regeneration process, is set to prohibit the automatic DPF regeneration process, a DPF regeneration control device (4) is made able to start a process to cancel execution of the automatic DPF regeneration process. If the selection device (7) is set to allow the automatic DPF regeneration process, the DPF regeneration control device (4) retracts the cancellation of the automatic DPF regeneration process, allowing execution of the previously-cancelled automatic DPF regeneration process to begin.

Abstract: A fine particle collecting filter includes a honeycomb structure in which a plurality of honeycomb segments are integrally joined by a joining material, and has a constitution where an exhaust gas allowed to flow from an inlet end surface into cells passes partition walls, and then flows out from an outlet end surface to the outsides of the cells. In the partition walls, SiC which is an aggregate is bound by Si which is a binding agent, at least one of an average open diameter of the pores of an inlet side of the exhaust gas passing the partition wall and an average open diameter of the pores of an outlet side is from 0.1 to 5 ?m, an average pore diameter of the whole partition wall is from 10 to 30 ?m, and a thermal conductivity of the partition walls at room temperature is from 50 to 80 W/mK.

Abstract: There is provided a honeycomb filter including a honeycomb base material including a porous partition wall parent material; plugged portions arranged in open frontal areas of predetermined cells in an end surface on an inflow side of the fluid, and open frontal areas of the remaining cells in an end surface on an outflow side of the fluid; and a porous collecting layer disposed on the surface of the partition wall parent material in the remaining cells. In a cross section orthogonal to an extending direction of the cells, a shape of the cells is a rectangular shape, and a thickness of a portion of the collecting layer which is positioned in each of corner portions of each of the cells is from one to three times that of a portion of the collecting layer which is positioned in the center of each of sides of the cell.

Abstract: There is provided a honeycomb filter including: a honeycomb base material; plugged portions; and a porous collecting layer disposed on the surface of the partition wall parent material in at least the remaining cells. The collecting layer has a constitution in which a plurality of particles combine or intertwine with one another, and the collecting layer includes flat plate-like particles as the plurality of particles. The plurality of particles are particles in which an average long diameter is 0.2 ?m or larger and smaller than 10 ?m, an average value of ratios (long diameters/short diameters) of the long diameters to the short diameters of the respective particles is smaller than 3, and an average value of ratios (the long diameters/thicknesses) of the long diameters to thicknesses of the respective particles is 3 or larger. An open area ratio of the surface of the collecting layer is 10% or larger.

Abstract: An exhaust treatment unit including a longitudinal core around an axis, a support mat, and powdered insulation impregnated between first and second layers of the support mat. In assembly, the mat is first wrapped around the core once, and powdered insulation is applied to the surface of the unwrapped portion of the mat prior to further winding whereby powdered insulation is disposed between mat layers after further winding.

Abstract: A method for converting soot particles of an exhaust gas includes providing at least nitrogen dioxide or oxygen in the exhaust gas, ionizing soot particles with an electric field, depositing electrically charged soot particles on inner channel walls of at least one surface precipitator, and bringing at least nitrogen dioxide or oxygen into contact with the deposited soot particles on the inner channel walls of the at least one surface precipitator. A device for carrying out the method includes at least one surface precipitator having a plurality of channels through which the exhaust gas can flow and extending between an inlet region and an outlet region, and at least one deposit inhibitor for electrically charged soot particles provided in at least part of the inlet region, especially allowing the soot particles to be evenly deposited and the surface precipitator to be continuously regenerated.

Abstract: A honeycomb filter includes a tubular honeycomb structure having porous partition walls with which there are formed a plurality of cells extending from one end surface to the other end surface to become through channels of a fluid; and plugged portions arranged in one open end portion of each of predetermined cells and the other open end portion of each of the remaining cells, porosities of the partition walls are 46% or less, a pore volume ratio of pores having pore diameters of 40 ?m or more is 7.5% or less, and a pore volume ratio of pores having pore diameters of 10 ?m or less is 25% or less, a permeability of the honeycomb structure is 0.8 ?m2 or more, and a coefficient of thermal expansion of the honeycomb structure in a range of 40 to 800° C. is 1.0×10?6/° C. or less.