Catalyst status detection method e.g. for NOx storage catalyst, involves having interior of housing of catalyst having gas in it and having quality measure of cavity for gas with resonant frequency decreased as measure of increase of NOx

摘要

The method involves having the interior of a housing (11) of a catalyst (10) having gas in it and having a quality measure of a cavity for the gas. The resonant frequency is decreased as a measure of an increase of NOx and such a reading is evaluated. The shift of the resonator quality as measure for carbon dioxide is evaluated.