Fan R.P.M. control loop stabilization using high rotor speed

摘要

A fan spool stabilization loop which improves the stability of the low speed or fan spool in a two spool turbofan engine. In a preferred embodiment, the actual rate of rotation of the high speed spool is compared with the desired rate of rotation determined by integrating the difference between the desired rate of rotation of the fan spool and the actual rate of rotation. The difference therebetween controls the flow of fuel to the turbofan engine. In an alternate preferred embodiment of the invention, the rate of change of rotation of the high speed spool is added to the actual rate of rotation of the fan spool and the result is compared with the desired rate of rotation of the fan spool. The difference therebetween is utilized to control the flow of fuel to the turbofan engine.