Method for desulphurisation of an NO_x accumulator-catalyst arranged in an exhaust system of an internal combustion engine

摘要

A method for the desulfurization of an NO_x storage catalyst arranged in an exhaust system of an internal combustion engine, whereby, for the desulfurization, the internal combustion engine is alternatingly operated in a lean mode at lambda>1 and a rich mode at lambda<1. During the desulfurization process, the present invention provides for the progress of the desulfurization being monitored, using a change in a parameter relating to intervals (I_n), whereby the interval (I_n) lasts from the beginning of an n_th rich operating phase (T_f,n), until the measured value drops below a predetermined lambda threshold value (S_f) downstream from the NO_x storage catalyst ( 16 ). Furthermore, the progress of the desulfurization is monitored, using a change in a lambda probe voltage (U_n) downstream from the NO_x storage catalyst ( 16 ), which is determined at the end of a predetermined interval at the beginning of an n_th rich operating phase (T_f,n).