Abstract: A method for actively calculating a capability of an electronically controlled valve is provided. The method including the steps of: a) operating the electronically controlled valve in accordance with a task; b) testing the electronically controlled valve in order to determine a range of movement of the electronically controlled valve in accordance with an initial gain, wherein the testing of the electronically controlled valve occurs after the valve has been operated in accordance with the task; c) determining a new gain required for providing a predetermined range of movement of the electronically controlled valve; and d) repeating steps a-c at least once, wherein the new gain is used to operate the valve in accordance with the task.

Abstract: A starter air valve (SAV) system can include a pressure actuated SAV actuator configured to be operatively connected to a SAV and a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator. The first pressure valve can be a pulse-width modulation solenoid valve configured to provide a duty cycle of pressure from the pressure source to the SAV actuator.

Abstract: According to an aspect, a correction factor for a fuel flow of a fuel system of an engine is determined. A nominal fuel flow is determined based on a metering valve stroke. The correction factor is applied to the nominal fuel flow to produce an estimated fuel flow to control combustion in the engine.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a bowed rotor prevention motor. A motor shaft of the bowed rotor prevention motor is operable to drive rotation of the gas turbine engine through an engine accessory gearbox. The motor shaft interfaces with an air turbine operable to rotate an output shaft mechanically linked to the engine accessory gearbox. The bowed rotor prevention system also includes a controller operable to engage the bowed rotor prevention motor and drive rotation of the gas turbine engine below an engine starting speed until a bowed rotor prevention threshold condition is met.

Abstract: A starter air valve (SAV) system includes a pressure actuated SAV actuator configured to be operatively connected to a SAV, a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator, and a second pressure valve configured to selectively allow pressure from the pressure source to the SAV actuator when in fluid communication with the SAV actuator. A manual override (MOR) valve selector is disposed between the first pressure valve, the second pressure valve, and the SAV actuator, the MOR valve selector configured to selectively fluidly connect the first pressure valve and the SAV actuator in a first position and to fluidly connect the second pressure valve and the SAV actuator in a second position.

Abstract: A method for actively calculating a capability of an electronically controlled valve is provided. The method including the steps of: a) operating the electronically controlled valve in accordance with a task; b) testing the electronically controlled valve in order to determine a range of movement of the electronically controlled valve in accordance with an initial gain, wherein the testing of the electronically controlled valve occurs after the valve has been operated in accordance with the task; c) determining a new gain required for providing a predetermined range of movement of the electronically controlled valve; and d) repeating steps a-c at least once, wherein the new gain is used to operate the valve in accordance with the task.

Abstract: A method for actively calculating a capability of an electronically controlled valve is provided. The method including the steps of: a) operating the electronically controlled valve in accordance with a task; b) testing the electronically controlled valve in order to determine a range of movement of the electronically controlled valve in accordance with an initial gain, wherein the testing of the electronically controlled valve occurs after the valve has been operated in accordance with the task; c) determining a new gain required for providing a predetermined range of movement of the electronically controlled valve; and d) repeating steps a-c at least once, wherein the new gain is used to operate the valve in accordance with the task.

Abstract: A method for controlling a gas turbine engine having a constrained model based control (CMBC) system. The method including obtaining information about a current and previous states of the engine, updating model data information in the CMBC and a parameter estimation system based on the obtained information, and identifying trends in the data based on the information. The method also includes diagnosing the engine, based on the identified trends, determining at least one of a new constraint, objective, initial condition, model characteristic, prediction horizon, and control horizon for the control system based on the diagnosing step if the diagnosing step identified a fault condition, and adapting the CMBC system based on the at least one new constraint, objective, initial condition, model characteristic, prediction and control horizon. The method further includes generating at least on control command based on the adapting and commanding an actuator based on the control command.

Abstract: A starter air valve (SAV) system can include a pressure actuated SAV actuator configured to be operatively connected to a SAV and a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator. The first pressure valve can be a pulse-width modulation solenoid valve configured to provide a duty cycle of pressure from the pressure source to the SAV actuator.

Abstract: According to an aspect, a method includes generating, by a computer processor, thermo-fluid parameter estimates of a thermal management system (TMS) of an engine based on sensed parameters and monitoring for TMS component failures based on the thermo-fluid parameter estimates and the sensed parameters. Thermo-mechanical parameter estimates are generated based on selected thermo-fluid parameters. Life usage estimates and life usage rate estimates are generated based on the selected thermo-fluid parameters and the thermo-mechanical parameter estimates. Life usage rate targets are generated based on external commands and the life usage estimates. Limits and goals are modified based on the life usage rate estimates, failure flags, and the life usage rate targets. A model predictive control is applied to command one or more TMS control components based on thermo-mechanical model parameters, the failure flags, and the limits and goals.

Abstract: A system and methods of estimating and controlling fuel flow in a gas turbine engine are disclosed. The system and methods include providing a metering valve and a pressure regulating valve. The system and methods further include determining a differential pressure error of the pressure regulating valve based on a metering valve inlet pressure, a discharge pressure, and a bypass fuel flow and determining a metering valve fuel flow based on a metering valve position and the differential pressure error.

Abstract: A starter air valve (SAV) system includes a pressure actuated SAV actuator configured to be operatively connected to a SAV, a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator, and a second pressure valve configured to selectively allow pressure from the pressure source to the SAV actuator when in fluid communication with the SAV actuator. A manual override (MOR) valve selector is disposed between the first pressure valve, the second pressure valve, and the SAV actuator, the MOR valve selector configured to selectively fluidly connect the first pressure valve and the SAV actuator in a first position and to fluidly connect the second pressure valve and the SAV actuator in a second position.

Abstract: A fuel system for a gas turbine engine includes, among other things, a plurality of components defining a plurality of localized nodes at distinct locations relative to a fuel flow path, each of the plurality of localized nodes characterized by a distinct set of failure parameters. One or more fuel sensors are configured to measure at least one fuel condition relating to flow through the fuel flow path. A fuel observation assembly is coupled to one or more engine sensors configured to measure at least one engine condition.

Abstract: A method for controlling a gas turbine engine having a constrained model based control (CMBC) system. The method including obtaining information about a current and previous states of the engine, updating model data information in the CMBC and a parameter estimation system based on the obtained information, and identifying trends in the data based on the information. The method also includes diagnosing the engine, based on the identified trends, determining at least one of a new constraint, objective, initial condition, model characteristic, prediction horizon, and control horizon for the control system based on the diagnosing step if the diagnosing step identified a fault condition, and adapting the CMBC system based on the at least one new constraint, objective, initial condition, model characteristic, prediction and control horizon. The method further includes generating at least on control command based on the adapting and commanding an actuator based on the control command.

Abstract: A bowed rotor prevention system for a gas turbine engine includes a bowed rotor prevention motor. A motor shaft of the bowed rotor prevention motor is operable to drive rotation of the gas turbine engine through an engine accessory gearbox. The motor shaft interfaces with an air turbine operable to rotate an output shaft mechanically linked to the engine accessory gearbox. The bowed rotor prevention system also includes a controller operable to engage the bowed rotor prevention motor and drive rotation of the gas turbine engine below an engine starting speed until a bowed rotor prevention threshold condition is met.

Abstract: A starter air valve (SAV) system includes a pressure actuated SAV actuator configured to be operatively connected to a SAV, a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator, and a second pressure valve configured to selectively allow pressure from the pressure source to the SAV actuator when in fluid communication with the SAV actuator. A manual override (MOR) valve selector is disposed between the first pressure valve, the second pressure valve, and the SAV actuator, the MOR valve selector configured to selectively fluidly connect the first pressure valve and the SAV actuator in a first position and to fluidly connect the second pressure valve and the SAV actuator in a second position.

Abstract: A starter air valve (SAV) system includes a pressure actuated SAV actuator configured to be operatively connected to a SAV, a first pressure valve configured to selectively allow pressure from a pressure source to the SAV actuator when in fluid communication with the SAV actuator, and a second pressure valve configured to selectively allow pressure from the pressure source to the SAV actuator when in fluid communication with the SAV actuator. A manual override (MOR) valve selector is disposed between the first pressure valve, the second pressure valve, and the SAV actuator, the MOR valve selector configured to selectively fluidly connect the first pressure valve and the SAV actuator in a first position and to fluidly connect the second pressure valve and the SAV actuator in a second position.

Abstract: A multivariable fuel control and estimator (MFCE) of a gas turbine engine for preventing combustor blowout is provided. The MFCE includes a first input port that receives controller requests and provide system usage commands, a second input port that receives measured disturbance values, a third input that receives system and component limits, a fourth input port that receives sensed parameters, a fuel system model of the fuel system of the gas turbine engine and an engine model of the engine system that includes the combustor of the gas turbine engine, a processor that generates a control signal for controlling the fuel valve and generates a control signal for controlling the actuator using the fuel system and engine model based on the controller requests, the measured disturbance values, the system and component limits, and the sensed parameters, and an output port that transmits the control signals to the fuel system.

Abstract: According to an aspect, a method includes generating, by a computer processor, thermo-fluid parameter estimates of a thermal management system (TMS) of an engine based on sensed parameters and monitoring for TMS component failures based on the thermo-fluid parameter estimates and the sensed parameters. Thermo-mechanical parameter estimates are generated based on selected thermo-fluid parameters. Life usage estimates and life usage rate estimates are generated based on the selected thermo-fluid parameters and the thermo-mechanical parameter estimates. Life usage rate targets are generated based on external commands and the life usage estimates. Limits and goals are modified based on the life usage rate estimates, failure flags, and the life usage rate targets. A model predictive control is applied to command one or more TMS control components based on thermo-mechanical model parameters, the failure flags, and the limits and goals.

Abstract: A fuel system for a gas turbine engine includes, among other things, a plurality of components defining a plurality of localized nodes at distinct locations relative to a fuel flow path, each of the plurality of localized nodes characterized by a distinct set of failure parameters. One or more fuel sensors are configured to measure at least one fuel condition relating to flow through the fuel flow path. A fuel observation assembly is coupled to one or more engine sensors configured to measure at least one engine condition.