MODEL BASED FUEL-AIR RATIO CONTROL

A gas turbine engine comprises a compressor (30, 32) , a combustor (14), a turbine (34, 36), and an electronic engine control system (102). The compressor, combustor, and turbine are arranged in flow series. The electronic engine control system is configured to estimate combustor fuel-air ratio based on a realtime model-based estimate of combustor airflow, and commands engine actuators to correct for a difference between the estimated combustor fuel-air ratio and a limit fuel-air ratio selected to avoid lean blowout.