a plurality of combustion chambers each having a piston reciprocally movable therein to perform a combustion cycle;

an aftertreatment device disposed in an exhaust system communicating with the plurality of combustion chambers;

a plurality of injectors disposed one each in the plurality of combustion clambers to introduce a total regeneration quantity of dosing fuel for regenerating the aftertreatment device; and

a controller communicating with the plurality of injectors and configured to group the plurality of combustion chambers into active combustion chambers and inactive combustion chambers such that the total regeneration quantity of dosing fuel is collectively introduced via the fuel injector of each active combustion chamber during an in-cylinder (ICD) control, and to determine a number of dosing shots to performed by the fuel injector of each active combustion chamber so as to achieve the total regeneration quantity of dosing fuel,

wherein a first total apportionment of the dosing fuel is allocated to the injector of a first active combustion chamber,

wherein a distribution of the first total apportionment of dosing fuel is non-uniform across the determined number of dosing shots for the first active combustion chamber, and

wherein the controller uses a bitmap to identify the combustion chambers to be active for introducing, the total regeneration quantity of dosing fuel.