Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed, where the controller modulates a duty cycle of the discrete starter valve via pulse width modulation.

Abstract: A system for controlling a start sequence of a gas turbine engine includes an electronic engine control system, a thermal model, memory, a model for determining a time period (tmotoring), and a controller. The thermal model synthesizes a heat state of the gas turbine engine. The memory records the current heat state at shutdown and a shutdown time of the gas turbine engine. The model for determining the time period is for motoring the gas turbine engine at a predetermined speed Ntarget that is less than a speed to start the gas turbine engine, where tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to a previous shutdown time. The controller modulates a starter valve to maintain the gas turbine engine within a predetermined speed range of NtargetMin to NtargetMax for homogenizing engine temperatures.

Abstract: A system is provided for speed control during motoring of a gas turbine engine of an aircraft. The system includes an air turbine starter, a starter air valve operable to deliver compressed air to the air turbine starter, and a controller. The controller is operable to adjust the starter air valve to control motoring of the gas turbine engine based on measured feedback with lead compensation to reject disturbances attributable to dual to single or single to dual engine starting transitions.

Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed, where the controller modulates a duty cycle of the discrete starter valve via pulse width modulation.

Abstract: A system for controlling a start sequence of a gas turbine engine includes an electronic engine control system, a thermal model, memory, a model for determining a time period (fmotoring), and a controller. The thermal model synthesizes a heat state of the gas turbine engine. The memory records the current heat state at shutdown and a shutdown time of the gas turbine engine. The model for determining the time period is for motoring the gas turbine engine at a predetermined speed Ntarget that is less than a speed to start the gas turbine engine, where tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to a previous shutdown time. The controller modulates a starter valve to maintain the gas turbine engine within a predetermined speed range of NtargetMin to NtargetMax for homogenizing engine temperatures.

Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed.

Abstract: A system is provided for speed control during motoring of a gas turbine engine of an aircraft. The system includes an air turbine starter, a starter air valve operable to deliver compressed air to the air turbine starter, and a controller. The controller is operable to adjust the starter air valve to control motoring of the gas turbine engine based on measured feedback with lead compensation to reject disturbances attributable to dual to single or single to dual engine starting transitions.

Abstract: A more-electric engine (MEE) system configured to operate in a plurality of operating modes includes a first power generating sub-system and a second power generating sub-system. The first power generating sub-system is configured to output electric power to a first power bus. The second power generating sub-system is configured to output electric power to a second power bus. The MEE system further includes an electronic source/load management and distribution (SLMD) module in power and signal communication with each of the first power generating sub-system, the second power generating sub-system, and the plurality of electrical sub-systems. The electronic SLMD module is configured to selectively operate the MEE system in one of a first operating mode or a second operating mode among the plurality of operating modes. The first and second operating modes adjust the delivery of the first and second electric power to the first and second power buses.

Abstract: A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed.

Abstract: A control system comprises an active dead band, coupled to a feedback path of the control system, configured to receive a first signal derived from a motor position signal of the feedback path of the control system and a utilize, in accordance with the signal, a set of thresholds to prevent feedback noise within a driveline of the control system.

Abstract: A more-electric engine (MEE) system configured to operate in a plurality of operating modes includes a first power generating sub-system and a second power generating sub-system. The first power generating sub-system is configured to output electric power to a first power bus. The second power generating sub-system is configured to output electric power to a second power bus. The MEE system further includes an electronic source/load management and distribution (SLMD) module in power and signal communication with each of the first power generating sub-system, the second power generating sub-system, and the plurality of electrical sub-systems. The electronic SLMD module is configured to selectively operate the MEE system in one of a first operating mode or a second operating mode among the plurality of operating modes. The first and second operating modes adjust the delivery of the first and second electric power to the first and second power buses.

Abstract: A control system comprises an active dead band, coupled to a feedback path of the control system, configured to receive a first signal derived from a motor position signal of the feedback path of the control system and a utilize, in accordance with the signal, a set of thresholds to prevent feedback noise within a driveline of the control system.

Abstract: Three separate fuzzy rule sets are applied to three corresponding fuzzy sets developed from various input parameters for providing a pitch engagement/mode selection management system and method for requesting disablement of a blade lock, for disabling such lock when the torque available matches the torque required, and for selecting a motor or brake for creating a differential speed between a rotating pitch change mechanism and a fan shaft of a turbine engine. A fuzzeresis rule set is disclosed for stabilizing the motor/brake mode selection fuzzy logic output.