Patent ID: 8079221

Claim:
A system, comprising: a gas turbine engine including a variable geometry mechanism with a number of vanes, the variable geometry mechanism being operable to vary working fluid flow area between the vanes over a range extending from a first extreme to a second extreme, one of the first extreme and the second extreme defining a greater flow area than another of the first extreme and the second extreme; an input device coupled to the gas turbine engine that is operable to select a desired state of the variable geometry mechanism different than a current state of the variable geometry mechanism, the desired state being closer to the first extreme than the current state; a controller responsive to the input device to generate one or more control signals to control hysteresis of the variable geometry mechanism according to a hysteresis band; and wherein the variable geometry mechanism is responsive to the control signals to change from the current state to an interim state closer to the first extreme than the desired state and subsequently to change from the interim state to the desired state.