Process for management of a catalyst used to clean an engine exhaust gas internal combustion device for the implementation of METHOD

A method of managing a catalyst (14) used to clean the exhaust gas of an internal combustion engine (10) wherein upstream of the catalyst (14) a reagent necessary for the catalyst (14) is introduced into the channel control echappement.On gas or is controlled by the filling level of the catalyst reagent (14) following a predetermined accumulation setpoint value (NH3-SP SW.).