Abstract: A method for calibrating a fuel control valve assembly including a valve and an actuator is disclosed. The method includes determining an encoder offset by actuating the valve until a predetermined value for the effective flow area is measured to obtain an actual calibration encoder count and comparing the actual calibration encoder count to an initial calibration encoder count. The method also includes adjusting an alignment encoder count and a maximum encoder count by an amount of the encoder offset. The method further includes associating the adjusted alignment encoder count with an alignment command value and the adjusted maximum encoder count with a maximum command value.

Abstract: A method for calibrating a fuel control valve assembly including a valve and an actuator is disclosed. The method includes determining an encoder offset by actuating the valve until a predetermined value for the effective flow area is measured to obtain an actual calibration encoder count and comparing the actual calibration encoder count to an initial calibration encoder count. The method also includes adjusting an alignment encoder count and a maximum encoder count by an amount of the encoder offset. The method further includes associating the adjusted alignment encoder count with an alignment command value and the adjusted maximum encoder count with a maximum command value.

Abstract: A method for controlling a gas turbine engine fuel control valve during low flow conditions includes positioning the fuel control valve in an operating position. The method also includes determining a fuel control valve flow sensor flow rate while in the operating position and determining a corrected effective flow area (“Cda”) of the fuel control valve. The method further includes generating Cda versus command data with the corrected Cda and the operating position and inserting the generated Cda versus command data into the nominal Cda versus command data set when nominal Cda versus command data is not known at the operating position.

Abstract: A method for controlling a gas turbine engine fuel control valve during low flow conditions includes positioning the fuel control valve in an operating position. The method also includes determining a fuel control valve flow sensor flow rate while in the operating position and determining a corrected effective flow area (“Cda”) of the fuel control valve. The method further includes generating Cda versus command data with the corrected Cda and the operating position and inserting the generated Cda versus command data into the nominal Cda versus command data set when nominal Cda versus command data is not known at the operating position.

Abstract: A method for operating a gas turbine engine fuel system with a fuel control valve is disclosed. The method includes metering fuel through the fuel control valve with an effective flow area versus command data set. The method also includes detecting that a change in an effective flow area of the fuel control valve has occurred. The method further includes modifying the effective flow area versus command data set to reflect the detected change in the effective flow area of the fuel control valve.

Abstract: A fuel valve for a gas turbine engine includes a passageway configured to direct a fuel to the engine and a flow restriction positioned in the passageway. The fuel valve may also include a first pressure sensor coupled to the passageway upstream of the restriction through an upstream port, and a second pressure sensor coupled to the passageway downstream of the restriction through a downstream port. The fuel valve may further include a third pressure sensor coupled to the upstream port through a first branch port, and a fourth pressure sensor coupled to the downstream port through a second branch port.

Abstract: A method of operating a drive system for a load is disclosed. The drive system may have an electric motor/generator and a gas turbine engine. The engine may have a combustor, and main and pilot flow paths via which fuel is supplied to the combustor. The engine may be operable in low and standard emissions modes. A proportion of the fuel that is supplied to the combustor via the pilot flow path may be greater in the standard emissions mode than in the low emissions mode. The method may include determining an engine power requirement of the load, and whether the engine power requirement of the load is sufficiently large to operate the engine in the low emissions mode. Additionally, the method may include operating the electric motor/generator if the engine power requirement of the load is not sufficiently large to operate the engine in the low emissions mode.

Abstract: A method of operating a drive system for a load is disclosed. The drive system may have an electric motor/generator and a gas turbine engine. The engine may have a combustor, and main and pilot flow paths via which fuel is supplied to the combustor. The engine may be operable in low and standard emissions modes. A proportion of the fuel that is supplied to the combustor via the pilot flow path may be greater in the standard emissions mode than in the low emissions mode. The method may include determining an engine power requirement of the load, and whether the engine power requirement of the load is sufficiently large to operate the engine in the low emissions mode. Additionally, the method may include operating the electric motor/generator if the engine power requirement of the load is not sufficiently large to operate the engine in the low emissions mode.

Abstract: A method of operating a drive system for a load is disclosed. The drive system may have an electric motor/generator and a gas turbine engine. The engine may have a combustor, and main and pilot flow paths via which fuel is supplied to the combustor. The engine may be operable in low and standard emissions modes. A proportion of the fuel that is supplied to the combustor via the pilot flow path may be greater in the standard emissions mode than in the low emissions mode. The method may include determining an engine power requirement of the load, and whether the engine power requirement of the load is sufficiently large to operate the engine in the low emissions mode. Additionally, the method may include operating the electric motor/generator if the engine power requirement of the load is not sufficiently large to operate the engine in the low emissions mode.