Emergency fuel system

Claim 1

An emergency fuel control system for an aircraft engine, which emergency fuel control system includes means for supplying emergency fuel to the engine in an amount proportional to engine speed and compressure pressure ratio, said control system comprising: means for converting a pilot's throttle lever position into a demand compressor pressure ratio signal; means for sensing actual compressor inlet pressure and actual compressor outlet pressure; first fluidic means responsive to the pilot's throttle lever position and to said actual compressor inlet and outlet pressures, said first fluidic means for comparing actual compressor pressure ratio with demand compressor pressure ratio and providing an error signal as a fluidic control pressure; means providing fluidic sensor inputs corresponding to engine speed and jet pipe temperature for limiting engine performance; second fluidic means for computing actual compressor pressure ratio and for generating an output signal pressure as a particular function of engine compressor ratio; fluidic mixer means responsive to output signals from said first and second fluidic means to limit the output signal from said first fluidic means; and a fluidic output device which receives signals from the fluidic mixer means and which generates a signal which has substantially the same shape as the acceleration control signal but which is at a lower level and which is used to define the minimum amount of fuel that is safely required by the engine in order to maintain combustion.