Abstract: An exhaust gas purification filter has a honeycomb structure body and upstream side plug members. Cell holes are composed of inlet cell holes and outlet cell holes. In a central area and an outer peripheral area, a gas flow channel cross sectional area Sc1 of the outlet cell holes is larger than a gas flow channel cross sectional area So1 of the inlet cell holes, where Sc1<So1. A first ratio Rc is smaller than a second ratio Ro. The first ratio Rc is a ratio of Sc1 and Sc2. The second ratio Ro is a ratio of So1 to So2. In a first direction X and a second direction Y, the inlet cell holes and the outlet cell holes are alternately arranged, and the cell walls in the central area are larger in thickness than the cell walls in the outer peripheral area.

Abstract: An exhaust gas filter purifies exhaust gas containing particulate matter emitted from an engine. The filter has cell walls and cells surrounded by the cell walls. Through pores formed in the cell walls, adjacent cells are communicated. The cells have open cells opening along an axial direction of the filter, and plugged cells. An upstream end part of the plugged cell is plugged by a plug member. On a cross section perpendicular to the axial direction, a flow-passage sectional area of the plugged cells is larger than a flow-passage sectional area of the open cells. A total length of the filter is not less than a first standard value and is not more than a critical length Lm determined by respective predetermined equations.

Abstract: An exhaust gas purification filter has a honeycomb structure body and upstream side plug members. Cell holes are composed of inlet cell holes and outlet cell holes. In a central area and an outer peripheral area, a gas flow channel cross sectional area Sc1 of the outlet cell holes is larger than a gas flow channel cross sectional area So1 of the inlet cell holes, where Sc1<So1. A first ratio Rc is smaller than a second ratio Ro. The first ratio Rc is a ratio of Sc1 and Sc2. The second ratio Ro is a ratio of So1 to So2. In a first direction X and a second direction Y, the inlet cell holes and the outlet cell holes are alternately arranged, and the cell walls in the central area are larger in thickness than the cell walls in the outer peripheral area.

Abstract: An exhaust gas filter purifies exhaust gas containing particulate matter emitted from an engine. The filter has cell walls and cells surrounded by the cell walls. Through pores formed in the cell walls, adjacent cells are communicated. The cells have open cells opening along an axial direction of the filter, and plugged cells. An upstream end part of the plugged cell is plugged by a plug member. On a cross section perpendicular to the axial direction, a flow-passage sectional area of the plugged cells is larger than a flow-passage sectional area of the open cells. A total length of the filter is not less than a first standard value and is not more than a critical length Lm determined by respective predetermined equations.