EXHAUST PURIFICATION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

A particulate filter arranged inside an engine exhaust passage is provided with an exhaust gas inflow passage and an exhaust gas outflow passage arranged in alternating fashion, and a porous barrier separating the exhaust gas inflow passage from the exhaust gas outflow passage. The barrier is divided into a coated region in which the surface of the base material is coated with a coating layer having an average pore diameter smaller than the average pore diameter of the barrier base material, and a region downstream from the coated region in which the base material surface is not coated with the coating layer, the ash present in the exhaust gas being able to pass through the barrier in the uncoated region. A determination process is performed to determine whether or not the particulate matter collection efficiency of the particulate filter has fallen below an acceptable lower limit. A particulate matter (PM) removal process is performed when it has been determined that the particulate matter collection efficiency of the particulate filter has fallen below the acceptable lower limit.