| abstract |
An object of the invention is to suppress deposition of ash in a wall-flow particulate filter while curtailing drops in a trapping rate of PM. To attain the above object, the invention provides a wall-flow particulate filter delimited by porous partition walls having pores of a size that allows ash and ash aggregates to pass therethrough. In the filter, a coat layer having pores smaller than the pores of the partition walls is provided, at a region of the partition walls, from an upstream end thereof up to a position before a downstream end thereof. |