Performance Seeking Control

The Performance Seeking Control (PSC) effort followed the Adaptive Electronic Control System project. Previous engine control modes uti­lized on the HIDEC aircraft used stored schedules of optimum engine pressure ratios based an average engine on a normal standard day. Using digital flight control, inlet control, and engine control systems, PSC used highly advanced computational techniques and control laws to identify the actual condition of the engine components and optimize the overall propulsion system for best efficiency based on actual engine and flight conditions that the aircraft was encountering, ensuring the highest engine and maneuvering performance in all flight environments. PSC testing with the HIDEC aircraft began in 1990. Results of flight-testing with PSC included increased fuel efficiency, improved engine thrust dur­ing accelerations and climbs, and increased engine service life achieved by reductions in turbine inlet temperature. Flight-testing demonstrated turbine inlet temperature reductions of more than 160 °F. Such large operating temperature reductions can significantly extend the life of jet engines. Additionally, improvements in thrust of between 9 percent and 15 percent were observed in various flight conditions, including accel­eration and climb.[1265] PSC also included the development of methodolo­gies within the digital engine control system designed to detect engine wear and impending failure of certain engine components. Such infor­mation, coupled with normal preventative maintenance, could assist in implementing future fail-safe propulsion systems.[1266] The flight dem­onstration and evaluation of the PSC system at NASA Dryden directly contributed to the rapid transition of the technology into operational use. For example, PSC technology has been applied to the F100 engine

used in the F-15 Eagle, the F119 engine in the F-22 Raptor, and the F135 engine for the F-35 Lightning II.