METHOD FOR CONTROLLING THE OPERATION OF AN ENGINE SYSTEM

A method for controlling the operation of an engine system in a vehicle is provided The engine system includes an engine configured to operate in at least a two-stroke combustion mode and a four-stroke combustion mode, and an exhaust aftertreatment system, EATS configured to reduce emissions from the engine exhausts. The method comprising estimating or predicting the temperature of the EATS; estimating or predicting the emissions out of the EATS; n response of that the temperature of the EATS is below a predetermined temperature threshold, and that the emissions out of the EATS is above a predetermined emission threshold, performing a primary NOx emission reducing activity by operating the engine in a two-stroke combustion mode; subsequently to initiating the operation of the engine in a two-stroke combustion mode, and in response of that the emissions out of the EATS is below the predetermined emission threshold, changing engine operation from the two-stroke combustion mode to a four-stroke combustion mode.