The invention relates to a method for producing a wall-flow filter for removing fine particulate solids from gases, and to the use thereof for cleaning exhaust gases of an internal combustion engine. The invention also relates to a correspondingly produced exhaust-gas filter having a high filtration efficiency.

The invention relates to a method for producing a wall-flow filter for removing fine particulate solids from gases, and to the use thereof for cleaning exhaust gases of an internal combustion engine. The invention also relates to a correspondingly produced exhaust-gas filter having a high filtration efficiency.

A honeycomb filter body comprises: a clean filter pressure drop of (P.sub.1) and a clean filtration efficiency of (FE.sub.1); a porous ceramic honeycomb body comprising a first end, a second end, and a plurality of walls having wall surfaces defining a plurality of inner channels, the porous ceramic honeycomb body comprising a base clean filter pressure drop (P.sub.0) and a base clean filtration efficiency (FE.sub.0); and a porous inorganic layer disposed on one or more of the wall surfaces of the porous ceramic honeycomb body.

The disclosure relates to a method of forming a coated monolith article for the treatment of an exhaust gas. The method comprises the steps of: retaining a porous monolith article in a coating apparatus, the porous monolith article comprising a plurality of channels for the passage of an exhaust gas, each channel having a gas-contacting surface; depositing cementitious particles as a dry powder onto the gas-contacting surface of at least some of the channels; and reacting the cementitious particles with a liquid or gaseous reagent in situ within the porous monolith article to provide the coated monolith article.

An exhaust purification system may include at least one catalyst in an exhaust flow path of an internal combustion engine to decrease gaseous pollutants from an exhaust gas, a first particulate filter downstream of the catalyst, and a second particulate filter with a porosity lower and a lower mean pore size than the first particulate filter and in a bypass flow line downstream of the first particulate filter, the bypass flow line being configured to open and close based on at least one condition of the exhaust purification system or conditions of the exhaust gas. The second particulate filter may be configured to be removed and replaced when full. A method of purifying an exhaust gas through the exhaust purification system is also described.

Apparatus and methods are disclosed which apply inorganic particles to a plugged honeycomb body comprising porous walls, an inlet end and an outlet end. The apparatus comprises a particle counter and the method comprises counting a selected portion of the inorganic particles from a first sampling port upstream from the plugged honeycomb body and a second sampling port downstream from the plugged honeycomb body. The selected portion of the inorganic particles are in a preselected inorganic particle size range. Filtration efficiency can be determined while inorganic particles are being deposited, for example to increase filtration efficiency,

A particulate filter having a honeycomb structure of a matrix of interconnected porous walls including inlet cells and outlet cells defining a plurality of inlet channels and outlet channels, respectively, wherein at least a portion of the outlet cells are larger than any of the inlet cells, and a cross-sectional shape of at least some of the outlet channels is rectangular. Honeycomb extrusion dies, honeycomb bodies, honeycomb structures, and methods of manufacture are described, as are other aspects.

A honeycomb structure includes a central area and a reinforced outer peripheral area. For a boundary cell having cell walls with different wall thicknesses on two sides parallel with an imaginary parallel line, a thin wall thickness t1<a thick wall thickness t3, an inner wall thickness t2<an outer wall thickness t4, t1=t2, and t3=t4. The honeycomb structure includes a cross-shaped unit having a thin wall, an inner wall, a cell wall, and a cell wall and a cross-shaped unit having a thick wall, an outer wall, a cell wall, and a cell wall. The honeycomb structure also includes cross-shaped units extending vertically and horizontally from alternate cell vertexes arranged from a cell vertex as a starting point. In the central area and the reinforced outer peripheral area, the cell walls of each cross-shaped unit have a substantially equal wall thickness.

A honeycomb structure includes a central area and a reinforced outer peripheral area. For a boundary cell having cell walls with different wall thicknesses on two sides parallel with an imaginary parallel line, a thin wall thickness t1<a thick wall thickness t3, an inner wall thickness t2<an outer wall thickness t4, t1=t2, and t3=t4. The honeycomb structure includes a cross-shaped unit having a thin wall, an inner wall, a cell wall, and a cell wall and a cross-shaped unit having a thick wall, an outer wall, a cell wall, and a cell wall. The honeycomb structure also includes cross-shaped units extending vertically and horizontally from alternate cell vertexes arranged from a cell vertex as a starting point. In the central area and the reinforced outer peripheral area, the cell walls of each cross-shaped unit have a substantially equal wall thickness.

A honeycomb plugging apparatus that reduces slumping of the plugging patty. Honeycomb plugging apparatus includes a plugging head having an open-ended cavity formed from an end wall and a peripheral wall, and a support substructure provided in the open-ended cavity. Methods of plugging and manufacturing honeycomb bodies using the honeycomb plugging apparatus are provided, as are other aspects.