A method (100, 200), comprising: operating an internal combustion engine system including an engine with first and second cylinder banks (34a, 34b) each including at least one cylinder (12a-12h) for receiving fuel from a fuel system, an intake system for delivering air to each of the cylinders (12a-12h), and an exhaust system including a first aftertreatment system for receiving exhaust gases from the first cylinder bank and a second aftertreatment system for receiving exhaust gases from the second cylinder bank, and further comprising a first throttle (46a, 60a) connected to the first cylinder bank and a second throttle (46b, 60b) connected to the second cylinder bank; interpreting (104, 106) a thermal management event for the first aftertreatment system and a load condition of the internal combustion engine; characterized in that the method (100, 200) further comprises: in response to the thermal management event and the load condition being less than a throttle closing threshold, closing the first throttle (46a, 60a); determining a first fuelling amount to the first cylinder bank that produces an exhaust gas from the first cylinder bank in response to a target temperature condition for the first aftertreatment system; determining a second fuelling amount to the second cylinder bank that satisfies a differential between a torque request to the engine and a torque output by the first cylinder bank in response to the first fuelling amount; and maintaining the second throttle (46b, 60b) open when the second fuelling amount is greater than a low fuelling amount threshold while operating the engine with the first cylinder bank fuelled with the first fuelling amount and the second cylinder bank fuelled with the second fuelling amount. operating an internal combustion engine system including an engine with first and second cylinder banks (34a, 34b) each including at least one cylinder (12a-12h) for receiving fuel from a fuel system, an intake system for delivering air to each of the cylinders (12a-12h), and an exhaust system including a first aftertreatment system for receiving exhaust gases from the first cylinder bank and a second aftertreatment system for receiving exhaust gases from the second cylinder bank, and further comprising a first throttle (46a, 60a) connected to the first cylinder bank and a second throttle (46b, 60b) connected to the second cylinder bank; interpreting (104, 106) a thermal management event for the first aftertreatment system and a load condition of the internal combustion engine; characterized in that the method (100, 200) further comprises: in response to the thermal management event and the load condition being less than a throttle closing threshold, closing the first throttle (46a, 60a); determining a first fuelling amount to the first cylinder bank that produces an exhaust gas from the first cylinder bank in response to a target temperature condition for the first aftertreatment system; determining a second fuelling amount to the second cylinder bank that satisfies a differential between a torque request to the engine and a torque output by the first cylinder bank in response to the first fuelling amount; and maintaining the second throttle (46b, 60b) open when the second fuelling amount is greater than a low fuelling amount threshold while operating the engine with the first cylinder bank fuelled with the first fuelling amount and the second cylinder bank fuelled with the second fuelling amount. in response to the thermal management event and the load condition being less than a throttle closing threshold, closing the first throttle (46a, 60a); determining a first fuelling amount to the first cylinder bank that produces an exhaust gas from the first cylinder bank in response to a target temperature condition for the first aftertreatment system; determining a second fuelling amount to the second cylinder bank that satisfies a differential between a torque request to the engine and a torque output by the first cylinder bank in response to the first fuelling amount; and maintaining the second throttle (46b, 60b) open when the second fuelling amount is greater than a low fuelling amount threshold while operating the engine with the first cylinder bank fuelled with the first fuelling amount and the second cylinder bank fuelled with the second fuelling amount.