Method for controlling the operation of an exhaust aftertreatment system

A method for controlling the operation of an exhaust aftertreatment system (EATS) in a vehicle, the EATS comprising a fluid channel for providing a fluid pathway for the exhaust gases, a main SCR catalyst and a pre-SCR catalyst arranged in the fluid channel, the pre-SCR catalyst being arranged upstream the main SCR catalyst, a pre-injector arranged upstream the pre-SCR catalyst for providing reductant to the pre-SCR catalyst, a bypass channel fluidly connected to the fluid channel and arranged to bypass the pre-SCR-catalyst and the pre-injector, and a valve configured to control a split of exhaust gases between the pre-SCR catalyst and the bypass channel, the method comprising:

• determining the amount of ammonia stored in the pre-SCR catalyst;
• determining the temperature of the main SCR catalyst;
• in response of determining that the ammonia storage in the pre-SCR catalyst is below an ammonia storage threshold and that the temperature of the main SCR catalyst is above a temperature threshold, injecting reductant by the pre-injector and controlling the valve to allow a flow of exhaust gases to the pre-SCR catalyst sufficient for transporting the injected reductant to the pre-SCR catalyst for increasing the ammonia storage.