Abstract: An aircraft engine system includes a main engine having a main engine speed; a starter coupled to the main engine and configured to drive the main engine with compressed air; and an auxiliary power unit (APU) system coupled to the starter and configured to provide the compressed air to the starter. The APU system includes an APU with a compressor to generate the compressed air, and an APU electronic control unit (ECU) coupled to the APU, the APU ECU configured to receive the engine speed of the main engine and to control operation of the APU to modify an amount of the compressed air to the starter based on the main engine speed.

Abstract: A gas turbine engine starter-generator includes a housing assembly, a motor-generator, and a lubricant pump. The housing assembly includes a lubricant inlet port for receiving a flow of lubricant. The motor-generator is disposed within the housing assembly and is adapted to be coupled to an auxiliary power unit. The motor-generator is configured to selectively operate in either a motor mode or a generator mode. The lubricant pump is disposed within the housing assembly and includes one or more pump inlets and one or more pump outlets.

Abstract: An aircraft engine system includes a main engine having a main engine speed; a starter coupled to the main engine and configured to drive the main engine with compressed air; and an auxiliary power unit (APU) system coupled to the starter and configured to provide the compressed air to the starter. The APU system includes an APU with a compressor to generate the compressed air, and an APU electronic control unit (ECU) coupled to the APU, the APU ECU configured to receive the engine speed of the main engine and to control operation of the APU to modify an amount of the compressed air to the starter based on the main engine speed.

Abstract: An engine system for starting a gas turbine engine is provided. The system includes a starter generator coupled to the gas turbine engine and configured to provide torque to the gas turbine engine and a controller coupled to the starter generator and configured to provide a command signal to the starter generator. The starter generator provides the torque to the gas turbine engine based on the command signal, and the controller is configured to command the starter generator at a dwell speed until ignition.

Abstract: An engine system for starting a gas turbine engine is provided. The system includes a starter generator coupled to the gas turbine engine and configured to provide torque to the gas turbine engine and a controller coupled to the starter generator and configured to provide a command signal to the starter generator. The starter generator provides the torque to the gas turbine engine based on the command signal, and the controller is configured to command the starter generator at a dwell speed until ignition.

Abstract: A gas turbine engine starter-generator includes a housing assembly, a motor-generator, and a lubricant pump. The housing assembly includes a lubricant inlet port for receiving a flow of lubricant. The motor-generator is disposed within the housing assembly and is adapted to be coupled to an auxiliary power unit. The motor-generator is configured to selectively operate in either a motor mode or a generator mode. The lubricant pump is disposed within the housing assembly and includes one or more pump inlets and one or more pump outlets.

Abstract: An auxiliary power unit (APU) is provided and configured to be mounted in an APU compartment that defines an inlet opening. The APU includes a power section having components lubricated with oil; an intake duct coupled to the inlet opening and the power section and configured to direct a first portion of air flow through the inlet opening into the power section; an oil cooler coupled to the power section and configured to cool the oil of the power unit; a cooling duct coupled to the oil cooler and the intake opening; an inlet door mounted at the inlet opening and configured to open and close the inlet opening, the inlet door further configured to be positioned in at least a first open position and a second open position; and a thermal management system configured to adjust the inlet door between the first open position and the second open position based on one or more operating temperatures within the APU.

Abstract: An on/off surge prevention control and method for a gas turbine engine having a variable geometry diffuser is provided. This control receives exhaust gas temperature and compressor discharge pressure signals from the engine, and a signal from the aircraft indicative of a need for bleed air. When the aircraft signal is received, the control opens the diffuser to its maximum open setting, and when said aircraft signal is absent closes said diffuser to its minimum open setting. In the event that a faulty aircraft signal is received, the control senses changes in EGT, P3 and dP3/dt and compares these parameters to preselected values indicative of the compressor nearing surge. When the measured values reach the preselected values, the control closes the diffuser to it minimum open setting. By using a temperature signal in determining when to close the diffuser, unwanted closings due to operating transients in compressor discharge pressure are provided.

Abstract: A modulating surge prevention control and method for a gas turbine engine having a variable geometry diffuser is provided. The control calculates a maximum permissible compressor discharge pressure from a predetermined algorithim that is representative of the compressor discharge pressure when the compressor is operating at its minimum permissible surge margin with the diffuser in its maximum open position. The control also receives a signal from a sensor measuring the actual compressor discharge pressure. A error signal is formed by taking the difference between the measured pressure signal and the calculated signal. The control then continously adjusts the area of the diffuser so as to maintain the actual compressor discharge pressure at or below the calculated pressure. The calculated pressure is also corrected for variations in ambient temperature and altitude.