Fuel Pump System Configuration for the More Electric Engine 2011-01-2563

This paper describes study for fuel pump system configuration which is suitable for the MEE (More Electric Engine) system. The MEE is a new engine system concept which intends engine efficiency improvement, which results in a reduction of engine fuel burn and CO₂ emissions from aircraft. Final configuration of the MEE will contain various engine systems, such as fuel system, oil system and electric generating system, but we focus on high efficiency fuel systems as a first step of the MEE development. The MEE is an advanced engine control technology utilizing recent innovations in electric motors and power electronics and replacing conventional engine accessories, such as AGB-driven pumps and hydraulic actuators with electric motor-driven pumps and EMAs (Electro-Mechanical Actuators), which are powered by generators. Because fuel pump system configuration is a key for the MEE fuel system, we conducted comparison of several pump systems and adopted a fixed displacement gear pump system. In the MEE gear pump system, the speed of which is controlled by an electric motor so that the pump discharges the exact fuel flow demanded by the FADEC (Full Authority Digital Electronic Control). When conventional AGB- and motor-driven gear pumps are compared in terms of power extraction from the engine, the latter takes less power than the AGB-driven pump because no bypass fuel flow is required. The MEE fuel system also improves engine oil heat management and allows the ACOC (Air-Cooled Oil Cooler), which worsens engine efficiency, to be eliminated. Assuming the MEE fuel system is introduced into a small size engine, we evaluated the engine efficiency improvement and confirmed that reduction of SFC (Specific Fuel Consumption) is expected by the MEE.