An exhaust gas purification system, which includes an engine and an exhaust pipe that is connected to an exhaust manifold of the engine, includes: a catalyst converter disposed at a rear side the engine on the exhaust pipe; a selective catalytic reduction on diesel particulate filter (SDPF) disposed at a rear side of the catalyst converter on the exhaust pipe; a reducing agent injector disposed between the catalyst converter and the SDPF on the exhaust pipe and injecting a reducing agent; and a controller controlling an amount of the reducing agent injected from the reducing agent injector.

The present invention provides a particulate filter for use in an emission treatment system of a gasoline engine, the filter having an inlet side and an outlet side, wherein at least the inlet side is loaded with a synthetic ash.

An exhaust gas purification catalyst having a substrate having a wall flow structure, and a catalyst layer. The catalyst layer has: an A section provided in the interior of the partition wall, along an extension direction X of the partition wall, from an exhaust gas inflow end section; a C section provided in the interior of the partition wall, along the extension direction X of the partition wall, from an exhaust gas outflow end section; and a B section disposed between the A section and the C section in the extension direction X of the partition wall, and provided over the surface of the partition wall on the side in contact with the inlet cell, the interior of the partition wall, and the surface of the partition wall on the side in contact with the outlet cell.

A honeycomb structure has a pillar-shaped honeycomb structure body having porous partition walls which defines cells which forms a passage of liquid extended from an inflow end face toward an outflow end face, a circumferential wall arranged to surround a circumference of the partition walls. The honeycomb structure body has an outermost circumference cell structure including a complete cell arranged at the outermost circumference of the honeycomb structure body, a center cell structure formed by the cells arranged at a center part at an inner side to the outermost circumference cell structure, and a boundary wall arranged at a boundary part between the outermost circumference cell structure and the center cell structure. The outermost circumference cell structure and the center cell structure are formed as different structures to each other, and a thickness of the boundary wall is set to be thicker than a thickness of the circumferential wall.

The honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, as to the honeycomb structure body, in a plane perpendicular to a cell extending direction, a cell structure of a central cell structure differs from a cell structure of a circumferential cell structure, and in the plane, a geometric center of gravity of the honeycomb structure body exists at a position which is away from a geometric center of gravity of the central cell structure, and a distance between the respective centers of gravity is larger than a length of a half of a cell pitch of an outermost circumferential cell structure including complete cells formed at an outermost circumference of the honeycomb structure body.

A heater may include: a conductive ceramic cylinder tube in which cell-arrays are concentrically arranged, each cell-array including cells which are arranged in a circumstance direction of the ceramic cylinder tube; an inner electrode electrically coupled to an inner wall portion of the ceramic cylinder tube; and an outer electrode electrically coupled to an outer wall portion of the ceramic cylinder tube. Non-linear portions are radially arranged in the ceramic cylinder tube, each non-linear portion extending in a radial direction of the ceramic cylinder tube while having a plurality of bends or curves between the inner wall portion and outer wall portion of the ceramic cylinder tube. The inner and outer electrodes are provided such that current flows radially at least via said non-linear portions between the inner and outer electrodes.

A heater includes: a conductive ceramic cylinder tube provided with a plurality of cells, each cell being defined by a pair of first cell-walls and a pair of second cell-walls, each first cell-wall extending in a radial direction of the ceramic cylinder tube, and each second cell-wall extending so as to cross the radial direction of the ceramic cylinder tube; an inner electrode electrically coupled to an inner wall of the ceramic cylinder tube; and an outer electrode electrically coupled to an outer wall of the ceramic cylinder tube. Linear portions are radially arranged in the ceramic cylinder tube, each linear portion linearly extending in the radial direction of the ceramic cylinder tube so as to include a plurality of first cell-walls that are arranged on the same axial line that extends in the radial direction of the ceramic cylinder tube. The inner and outer electrodes are provided such that current flows radially at least via said linear portions between the inner and outer electrodes.

An exhaust gas purification filter comprises: a casing; a porous dividing wall which partitions the inside of the casing into a honeycomb shape; and cells enclosed by the dividing wall. A pore path length distribution of the dividing wall, when expressed by a frequency histogram per 10 m of the pore path length of the dividing wall, has an integrated frequency of at least 58%. The integrated frequency is a maximum value of a value obtained by summing the frequencies of a total of three adjacent levels which include the maximum peak frequency. The dividing wall preferably has a gas permeability coefficient k of at least 0.810.sup.12m.sup.2.

An exhaust gas purification filter is provided which has a high capture ratio of particulate matter even when having a high porosity. The exhaust gas purification filter has a case, partition walls and cells. The partition walls are porous, and the interior of the case is partitioned into a plurality of the cells by the partition walls. The partition walls have a plurality of communicating pores which communicate between cells adjacent to respective partition walls. The degree of tortuosity L/T of the communicating pores satisfies L/T1.1, where T m is the thickness of the partition walls and L m is the average flow path length of the communicating pores. Furthermore the exhaust gas purification filter is manufactured using porous silica having a tapped bulk density that is no greater than a predetermined value.

A honeycomb body for exhaust-gas aftertreatment and a method for producing the honeycomb body for exhaust-gas aftertreatment, the honeycomb body having a housing and a honeycomb structure with a multiplicity of channels. The honeycomb structure is formed with a partially structured layer and a smooth layer the smooth layer provides that, in at least one axial portion of the honeycomb structure, a first cell density in an inner radial zone is increased in relation to a second cell density in an outer radial zone.