摘要 |
A method of regenerating a particulate filter in an apparatus comprising an internal combustion engine and a catalyst that employs urea as reductant for NOx is disclosed. The method comprises exposing the catalyst and particulate filter to a first, lower elevated exhaust temperature to remove urea deposits and/or stored hydrocarbon from the catalyst, and then exposing the catalyst and particulate filter to a second, higher elevated exhaust temperature to heat the particulate filter to decompose particulate matter in the particulate filter. In this manner, damage caused to the catalyst due to the decomposition and reaction of urea deposits and/or oxidation of stored hydrocarbon during particulate filter regeneration may be avoided. |