Patent DE-102008042372-A1 (DE)
Title: Exhaust gas cleaning filter for diesel engine, comprises a honeycomb structure having cells that are divided into inlet cells and outlet cells by porous cell walls that are arranged in a honeycomb form, and plug parts
Inventor: MURATA TAKASHI
IPC: B01D39/20
Filed: 2008-09-25
Abstract: The exhaust gas cleaning filter for diesel engine, comprises a honeycomb structure (2) having cells (4) that are divided into inlet cells (41) and outlet cells (42) by porous cell walls (3) that are arranged in a honeycomb form, a plug part (5) that is formed in an end part of each inlet cells at a downstream side of the exhaust gas, and another plug part that is formed in an end part of each outlet cell at an upstream side of the exhaust gas. The exhaust gas is subjected through the inlet cells in the honeycomb structure and is released towards an outside of the honeycomb structure. The exhaust gas cleaning filter for diesel engine, comprises a honeycomb structure (2) having cells (4) that are divided into inlet cells (41) and outlet cells (42) by porous cell walls (3) that are arranged in a honeycomb form, a plug part (5) that is formed in an end part of each inlet cells at a downstream side of the exhaust gas, and another plug part that is formed in an end part of each outlet cell at an upstream side of the exhaust gas. The exhaust gas is subjected through the inlet cells in the honeycomb structure and is released towards an outside of the honeycomb structure in the exhaust gas cleaning filter through the outlet cells. The honeycomb structure fulfills a relation of D1 less than D2, where D1 denotes a hydraulic diameter of each inlet cells and D2 denotes a hydraulic diameter of each outlet cell in a cross section that lies right-angle to a longitudinal direction of the honeycomb structure, and a relation of S1 greater than S2, where S1 denotes a total sum of the cross-section area of the inlet cells and S2 denotes a total sum of the cross-section area of the outlet cells. The honeycomb structure fulfills a relation of K greater than 1.5, if the relation between D1 and D2 is expressed under use of K.D1 less than D2, where K is a constant, and the relation between the S1 and S2 is expressed through L greater than 1, if S1 greater than L. S2 is used, where L is constant. The number of inlet cells is larger than the number of outlet cells. The cells consist of rectangular cells, hexagonal cells and dodecagonal cells, which are formed in periodic manner and surrounded by cell walls that are arranged in rectangular, hexagonal and dodecagonal form respectively, or quadratic cells, triangular cells and hexagonal cells that are arranged in the honeycomb structure in periodic manner and surrounded by cell walls that are arranged in quadratic, triangular and hexagonal form respectively. Two hexagonal cells and the two dodecagonal cells are alternatively arranged around each rectangular cell or two triangular cells and two hexagonal cells are alternatively arranged around each quadratic cell, and the rectangular cells, hexagonal cells and dodecagonal cells split the cell walls around the rectangular cell so that the hexagonal cells assign to the dodecagonal cells or the triangular cells and the quadratic cell split the cell walls around the quadratic cell so that the triangular cells assign to the hexagonal cells. Three rectangular cells and the three dodecagonal cells are alternatively arranged around each hexagonal cell and the hexagonal cells, rectangular cells and dodecagonal cells split the cell walls around the hexagonal cell so that the rectangular cells assign to the dodecagonal cells, or three quadratic cells are arranged around each triangular cells and the triangular cell and the quadratic cell split the cell walls around the triangular cell so that the adjacent quadratic cells are assigned to each other. Six rectangular cells and the six hexagonal cells are alternatively arranged around each dodecagonal cell and the dodecagonal cells, rectangular cells and the hexagonal cells split the cell walls around the dodecagonal cell so that the dodecagonal cell assign to the hexagonal cells, or six quadratic cells are arranged around each hexagonal cell and the adjacent quadratic cells split the cell walls around the hexagonal cell so that the quadratic cells are assigned to each other. The rectangular cells and the hexagonal cells form the inlet cells and the dodecagonal cells form the outlet cells, or the quadratic cells and the triangular cells form the inlet cells and the hexagonal cells form the outlet cells. The relation of D1 less than D2 between the rectangular cells and the dodecagonal cells and between the hexagonal cells and the dodecagonal cells is fulfilled and the relation of D1 less than D2 between the quadratic cells and the hexagonal cells and between the triangular cells and the hexagonal cells is fulfilled.