EXHAUST PURIFICATION APPARATUS FOR INTERNAL COMBUSTION ENGINE

摘要

Provided is an exhaust purification apparatus for an internal combustion engine with a DPF disposed in the exhaust system of the internal combustion engine, such that accumulation of ash in the DPF can be suppressed, increases in pressure loss and PM regeneration temperature as well as a decrease in fuel efficiency can be suppressed over a long period, and the suppression of accumulation of ash can be efficiently performed. A surface of the DPF is coated with a solid acid with an acid strength greater than the acid strength of SO3 and smaller than the acid strength of SO4. The exhaust purification apparatus is provided with: a PM regeneration operation control; an ash regeneration operation control; and a learning control for determining the interval at which the ash regeneration operation is performed on the basis of a change in back pressure of the DPF before and after the PM regeneration operation is performed a plurality of times.