Method for recognition of state of selective catalytic reduction catalyst and diesel particulate filter in after-treatment of exhaust gases system, involves calculating reflectance factor amount of interfered electromagnetic wave

摘要

The method involves propagating an electromagnetic wave in a metallic housing, where the electromagnetic wave is interfered by an inserted selective catalytic reduction (SCR) catalyst and/or a diesel particulate filter. A reflectance factor amount is calculated with displacement of resonance frequencies of the interfered electromagnetic wave, and the states of the SCR catalyst and/or the filter are determined from the calculated reflectance factor amount.