The ever-increasing interest in global warming and air pollution has shaped the modern internal combustion engine. Over the years, new technologies were adopted to reduce emissions and fuel consumption. Various solutions have been implemented, such as Miller cycle, exhaust gas recirculation, multi-stage turbocharging, exhaust aftertreatment and cylinder deactivation. Wärtsilä has been investigating the latter technology for over a decade on its dual-fuel and natural gas engines, leading to a remarkable increase in engine efficiency at lower loads, as well as a more stable combustion process and lower hydrocarbon emissions. The aim of this master thesis project, conducted in collaboration with POWERTECH Engineering S.r.l.