Development of an Engine Controller for an Allison M250 Engine

Abstract The global demand to reduce harmful emissions drives the aviation industry towards cleaner and more efficient propulsion systems. In addition to sustainable aviation fuels, innovative engine cycle adaptations are gaining attention to further reduce emissions and increase efficiency. Implementing innovative engine cycles, such as Water-Enhanced Turbofan (WET), changes the operating conditions, which potentially leads to instability in the fuel control unit (FCU) of the existing fuel control system (FCS). The FCU manages the fuel flow and ensures safe engine operation by preventing conditions like rotor overspeed and turbine overtemperature. To address this, a digital FCU is developed to replace the existing pneumatic-mechanical controller of a modified Allison M250-C20B. This paper provides an overview of current FCU technologies, discusses the hardware developments for the fuel train in the laboratory, and explores the development of a digital electronic control unit (ECU) with domain randomization to account for model inaccuracies, enabling reliable control of innovative engine cycles.