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, and increases in pressure loss and PM regeneration temperature as well as a decrease in fuel efficiency can be suppressed over a long period. 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. An SOx adsorbing/releasing catalytic apparatus is provided upstream of the DPF in the exhaust system of the internal combustion engine. The exhaust purification apparatus performs: control for increasing the temperature of the DPF; air-fuel ratio control for the atmosphere within the DPF; and control for causing SO4 to be released from the SOx adsorbing/releasing catalytic apparatus when the flow rate of exhaust passing through the DPF exceeds a predetermined value during the control for increasing the temperature of the DPF.