Method for operating a combustion engine having a four-way catalyst

摘要

The method involves heating an oxidation catalyst of a combing exhaust after-treatment system to an allowed temperature, where an instantaneous temperature of the catalyst is smaller than the allowed temperature. The allowed temperature is raised to a correct value for inducing regeneration of a particle filter, where the temperature rise is provided as function of filter loading. The allowed temperature is raised to another correct value for desulphurization of a memory catalyst, where the temperature rise is provided as function of overall conversion rate of nitrogen oxide.