Adaptive gas turbine acceleration control

Claim 1

In a method for the exercise of control over the delivery of fuel to a gas turbine engine, the engine including a gas generator having a compressor, the engine further including a fuel metering system which is responsive to fuel flow command signals for varying the rate of delivery of fuel to the engine, an improved mode of varying fuel flow during acceleration of the engine comprising: storing data comprising an engine acceleration schedule which defines a ratio of a rate of change of gas generator speed to compressor discharge pressure for ratios of gas generator speed to compressor inlet temperature during acceleration, the acceleration schedule comprising a curve defined by a series of points; storing modifier values which correspond to the stored acceleration schedule data; detecting engine surges; varying at least that stored modifier value which corresponds to the point on the acceleration schedule at which a surge has occurred during one acceleration; combining the acceleration schedule data with the modifier values whereby the schedule data will be varied during accelerations occurring subsequent to the said one acceleration; and deriving fuel flow commands from the combined acceleration schedule data and modifier values.