Fuel control for a multi-engine gas turbine installation

Claim 1

An electronic fuel control for a multi engine gas turbine installation comprising a plurality of control channels for the respective engines, each control channel including an error signal integrator, first difference signal generating circuit for comparing the output of the integrator with a signal corresponding to the value of an engine parameter, a fuel supply system controlling the supply of fuel to the associated engine in accordance with the output of the first difference signal generating circuit, error signal generating means for comparing the desired value of an engine parameter with the actual value thereof, limiter means for limiting the output of the error signal generating means during acceleration to a value determined by engine operating conditions, the output of said limiter means being applied as said error signal to the integrator when the engines are running in a normal matched condition, and further limiter means in each channel for further limiting the output of said limiter means when the values of a parameter of the engine controlled by that channel and of the other or another engine of the system differ, said further limiter means including a second difference signal generating circuit having inputs corresponding to the error signal from the limiter means of at least one of the control channels and a signal corresponding to the difference between the value of said parameter for the two engines.