Control Requirements for the RB 211 Low-Emission Combustion System

The RB 211 DLE series staged, premix, lean burn combustor demands total integration of control system and combustion hardware. The controls design process is described from the conception of the Engine Management System (EMS), which provides protection and control in separate environments, through to implementation of engine development testing. The process of devising an acceptable fueling strategy to each combustion stage is discussed. This identified the requirements for the computation of complex routines in order to control combustion zone temperatures. The sensitivity of the control design to external conditions of humidity, ambient temperature, and fuel composition is explored. Extensive simulation was used to determine necessary instrumentation accuracies. The paper concludes with a review of the development testing and the final control system configuration.