Exhaust emission control system, method of calculating pressure loss of filter, and method of manufacturing filter

A method of calculating a pressure loss of a honeycomb filter including:

• at least two end faces;
• porous partition walls extending from one end face to the other end face;
• and a large number of through channels partitioned by the partition walls and extending from one end face through the other end face, predetermined through channels being plugged in one end face, remaining predetermined through channels being plugged in the other end face, the method comprising the steps of:
• decomposing the pressure loss into at least a pressure loss in a plugged portion, a pressure loss in the through channel, and a pressure loss in the partition wall;
• and decomposing the pressure loss in the partition wall into pressure losses in cases where any particulate matter is not deposited in the filter and where the particulate matters are deposited to calculate the pressure loss.

An exhaust emission control system comprising:

• an internal combustion engine;
• a filter for capturing particulate matters in an exhaust gas exhausted from the internal combustion engine;
• and an exhaust pipe for introducing the exhaust gas into the filter, the system comprising a combustion device for intermittently burning the particulate matters captured by the filter, the filter being a honeycomb filter including:
• at least two end faces;
• porous partition walls extending from one end face to the other end face;
• and a large number of through channels partitioned by the partition walls and extending from one end face through the other end face, predetermined through channels being sealed in one end face, remaining predetermined through channels being sealed in the other end face, wherein assuming that a partition wall thickness is (X) μm, and the number of through channels per unit area in a section vertical to a longitudinal direction of the through channels is (Y) cells/cm2, X and Y fall within a range surrounded by straight lines connecting points A3 (X is 330, Y is 42.7), B3 (X is 356, Y is 34.9), C3 (X is 406, Y is 34.9), and D3 (Xis 381, Y is 42.7) in this order wherein the filter has a combination of X and Y that keeps a temperature gradient below 180° C./cm at a time of filter regeneration to prevent cracks from being generated.