With growing concerns about energy efficiency and greenhouse gas emissions, there is a growing demand for a new generation of more economical engines. Most research focuses on small internal combustion engines used in the automotive sector. While there is larger internal combustion engines used in the naval sector and in power plants. This study presents the modelling of the generated torque of an 18-cylinder Wärtsilä diesel engine powering a 180 MW power plant in Mauritania. In order to maximise efficiency and minimise emissions, thermodynamic and mechanical elements are included in the simulation. Particular attention is paid to combustion, torque dynamics and cylinder pressure optimisation. To model torque and pressure, MATLAB simulations are paired with experimental pressure measurements taken over a month for each cylinder. By modelling the pressure, we can calculate the gas torque generated by each cylinder, which is added to the inertia torque due to the movement of the various components. The aim is to improve fuel efficiency, reduce emissions and ensure long-term engine reliability in demanding operating conditions.