A move to ‘more electric’ engines

Researchers detail a motor control design for the fuel system of a more electric aero engine, focusing on the necessary safety and reliability aspects.

Reducing fuel consumption is a key area of aviation technology, and improvements in aircraft engine design to enhance environmental performance have been ongoing for many years. The more electric aero engine (MEE) is an innovative control architecture for aircraft engines that introduces electric motor-driven accessories in place of the conventional accessory gearbox (AGB)-driven pumps or hydraulic actuators. The MEE is a highly effective approach, capable of improving engine efficiency and reducing fuel burn and CO₂ emissions.

Conventional AGB-driven fuel pumps are generally fixed displacement pumps (e.g., gear pumps). The speed of this fuel pump is proportional to core engine speed; the pump is designed to provide much greater flow than the actual engine burn flow. The fuel system must bypass the excess fuel flow to return to the fuel pump inlet. This flow of excess fuel can sometimes be several times greater than engine burn flow, and recirculating this excess flow can result in fuel system inefficiencies and increase fuel temperatures.