A method for monitoring a starting sequence of a turbomachine including a compressor provided with a rotor, a starter capable of rotating the rotor and a combustion chamber, the method including determining a bracketing of a time zone during which the ignition instant takes place, the bracketing being defined by, on the one hand, a lower limit corresponding to an event necessarily taking place before the ignition instant and an upper limit corresponding to an event necessarily taking place after the ignition instant; and determining between the lower limit and the upper limit, a break point in the variation with time of the measurement signal, this break point corresponding to an ignition instant of the air-fuel mixture in the combustion chamber.

Methods and systems for detecting an abnormal start of a gas turbine engine are described. Speed data points are sampled from a sensor associated with the engine in accordance with a sampling rate, the speed data points being indicative of a rotational speed of a gas generator of the engine during engine start. The speed data points are continuously stored during the engine start. Previously-obtained speed data points which are older than an abnormal start delay are discarded. An abnormal engine start event is detected by comparing a first one of the stored speed data points with a second one of the stored speed data points, the second one of the stored speed data points obtained before the first one.

A method for controlling noise emitted by a hybrid-electric gas turbine engine for an aircraft during a takeoff flight condition includes applying a first total rotational force to a shaft with a turbine and an electric motor. The first total rotational force includes a first electric rotational force applied by the electric motor and a first thermal rotational force applied by the turbine. The first total rotational force has a first rotational force ratio of the first electric rotational force to the first thermal rotational force. The method further includes controlling the noise emitted by the gas turbine engine by reducing the first rotational force ratio from an initial rotational force ratio of the rotational force ratio as an altitude of the aircraft increases and maintaining the first total rotational force substantially constant while reducing the rotational force ratio.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.

A method and device for detecting conditions conducive to the onset of pumping that can affect a low-pressure compressor of an aircraft turbine engine. The turbine engine including a high-pressure compressor. The method including measuring a speed variation of the aircraft and measuring a speed variation of the high-pressure compressor. The method including a preliminary step of measuring an altitude of the aircraft. The conditions conducive to the onset of pumping being detected when the following conditions are jointly obtained: (a) the speed variation measured over a predetermined time interval corresponds to an acceleration greater than a first positive threshold, (b) the measured speed variation corresponds to a deceleration less than a second negative threshold, and (c) the altitude is greater than a third predetermined threshold.

A system and method for adaptively controlling a cooldown cycle of an auxiliary power unit (APU) that is operating and rotating at a rotational speed includes reducing the rotational speed of the APU to a predetermined cooldown speed magnitude that ensures combustor inlet temperature has reached a predetermined temperature value, determining, based on one or more of operational parameters of the APU, when a lean blowout of the APU is either imminent or has occurred, and when a lean blowout is imminent or has occurred, varying one or more parameters associated with the shutdown/cooldown cycle.

A method and system for detecting a functional failure in a power gearbox, includes engine a) measuring operational data in a gas turbine engine of operational parameters dependent on power generation and power consumption of the engine or the gearbox, b) obtaining analyzed operational data including time data, angular data of rotation, frequency data and/or phase data, c) using the analyzed operational data in a comparison with stored baseline operational data to determine deviation data, d) determining time dependent trend data from the deviation data or determining a first state measured dependent on the power generation, power consumption or power regulation of the engine and measuring a second state dependent on vibrational data of the engine, e) generating a signal and/or a protocol for controlling the gearbox, and/or the engine based on the time dependent trend data, if a threshold is exceeded or based on the first or second states.

Systems and methods for adjusting a variable geometry mechanism of an engine are described herein. An engine control request indicative of a desired output power for the engine is monitored. A rate of change of the engine control request is determined. The rate of change is compared to a threshold. Responsive to determining that the rate of change is beyond the threshold, a transient bias map is applied to a steady-state schedule to generate a variable geometry mechanism request indicative of a target position for the variable geometry mechanism. The variable geometry mechanism is adjusted toward the target position according to the variable geometry mechanism request.

A control device is a device for controlling a gas turbine. The control device is provided with: a prediction unit configured to predict a future state quantity of the gas turbine corresponding to a control input to the gas turbine in a prediction horizon, using a prediction model; an optimization unit configured to optimize the control input in at least a part of the prediction horizon, using a prediction result of the prediction unit; a storage unit for storing sensitivity information indicating sensitivity of the control input to a change speed of the state quantity for each operating condition of the gas turbine; and an update unit configured to read the sensitivity information corresponding to the operating condition assumed in the prediction horizon from the storage unit, and update one or more coefficients of a prediction equation of the state quantity used in the prediction model.

The method can include determining a mass flow rate W of working fluid circulating through the compressor stage, determining a control parameter value associated to the geometrical configuration of the variable geometry element based on the determined value of mass flow rate W; and changing the geometrical configuration of the variable geometry element in accordance with the determined control parameter value.