An aircraft hybrid propulsion system (5) comprising an inboard gas turbine engine (10a, 10c) and an outboard gas turbine engine (10b, 10d), each comprising a propulsor (12a, 12b) and a respective electric machine (32a, 32b) coupled to one or more engine shaft (24a, 24b). An electrical interconnection (34) is provided between the electric machine (32a) of the inboard gas turbine engine (10a) and the electric machine (32b) of the outboard gas turbine engine (10b). A controller (36) is configured to transfer electrical power between the inboard gas turbine engine electrical machine and the outboard gas turbine engine electrical machine when a thrust setting change is selected.

A propulsion system for a hybrid electric vehicle comprises a traction motor having first and second stator windings; a power source having a DC power output coupled to the first windings; a battery having a DC power output coupled to the second windings; and a controller to independently control: (i) a first power level output at the first DC power output, and (ii) a second power level of motive power output by the traction motor; wherein responsive to a signal to set the second power level less than full capacity of the traction motor, the controller provides a power difference between the first and second power levels from the second windings to the battery.

A hybrid propulsion system with controllers and a drive shaft of a helicopter with a main rotor connected to a gearbox which can keep a flight attitude set by a pilot stable. It includes a pilot controller, a combustion engine and an electric motor, both of which act directly on the drive shaft. The VM is connected to a VM controller, and the EM is connected to an EM controller. One torque sensor and one tachometer are each arranged on the drive shaft, wherein during operation both the VM controller and the EM controller are able to receive values for the current speed and the current torque. Specified values for speed and torque, in which the VM can attain its optimum efficiency, are stored in memory and can be retrieved by the EM controller, wherein the first value can also be retrieved by the VM controller.

An assembly is provided for an aircraft. The aircraft assembly includes a rotating structure, a geartrain, a propulsor rotor and an electric machine. The rotating structure includes a turbine rotor. The geartrain includes a sun gear, a ring gear, a plurality of intermediate gears and a carrier. The sun gear is rotatably driven by the rotating structure. Each of the intermediate gears is between and meshed with the sun gear and the ring gear. Each of the intermediate gears is rotatably mounted to the carrier. The propulsor rotor is rotatably driven by the carrier. The electric machine is coupled to the ring gear.

A hydrogen-fuelled aircraft power system incorporates a gas turbine engine and a fuel cell, in which air supply and cooling of the fuel cell is integrated with the gas turbine engine to improve overall efficiency of the power system. The system may be part of a turbofan, turboprop or electric propulsion system for an aircraft.

Disclosed herein is a fundamental modeling and control method in dynamic energy conversion and transfers in complex energy systems with multiple energy sources, fuel and electric. The multi-layered modeling enables efficient and stable operation through optimized coordination of engines and electric part of a hybrid turbo-electric distribution system (TeDP). A provable coordination of power and rate of change of power interactions between the components is done at the higher-system level. Advanced nonlinear control of components is disclosed to ensure that components meet power/rate of change of power commands given by the higher level. This method is used to demonstrate, for the first time, how rotor stall and surge instabilities in engines can be eliminated by controlling the electric generators and/or storage.

A method for operating a propulsion system for an aircraft, the propulsion system including a gas turbine engine and a fuel cell assembly, the fuel cell assembly comprising a fuel cell stack having a fuel cell defining an outlet positioned to remove output products from the fuel cell during operation, the method including: executing a startup sequence for the gas turbine engine, wherein executing the startup sequence comprises initiating the startup sequence for the gas turbine engine; executing a startup sequence for the fuel cell assembly concurrently with, or subsequent to, initiating the startup sequence for the gas turbine engine; and operating the fuel cell assembly to provide output products to a combustion section of the gas turbine engine.

A propulsion assembly includes a first torque source coupled with a first shaft and a second torque source coupled with a second shaft. A coupler selectively couples the first and second torque sources. When the first and second torque sources are coupled via the coupler, in response to a command to decouple the first torque source, an unloading operation is performed to decrease the torque output provided by the first torque source to a threshold, and when reached, the first shaft is decoupled from the coupler. When the first torque source is coupled with the coupler but the second torque source is not, in response to a command to couple the second torque source, a speed matching operation is performed to increase the speed of the second shaft to match a speed of the first shaft, and when the speeds are matched, the second shaft is coupled to the coupler.

An aircraft propulsion system and method of cooling the same are provided. The system includes a hydraulic pump, an intermittent IC engine, a hydraulic motor, an engine oil pump, and a cooling system. The intermittent IC engine drives the hydraulic pump. The hydraulic motor is powered by the hydraulic pump and drives a propulsor fan. The cooling system includes a first heat exchanger (AIR-EO HEX) and a second heat exchanger (EO-HF HEX). The AIR-EO HEX transfers heat between flows of engine oil and ambient air. The EO-HF HEX transfers heat between flows of engine oil and hydraulic fluid. The hydraulic pump provides motive force to cause the hydraulic oil to pass through the EO-HF HEX and back to the at least one hydraulic pump. The engine oil pump provides motive force to pass the engine oil to and through the AIR-EO HEX, the EO-HF HEX, and the intermittent IC engine.

An aircraft propulsion system having a variable airflow capture area is provided. The propulsion system includes a main propulsion source and an auxiliary propulsion source. In a first mode, the auxiliary propulsion source is stowed within an aerodynamic profile of the aircraft, and the main propulsion source provides all of the propulsion force for powering flight of the aircraft. In a second mode, the auxiliary propulsion source is deployed to augment the airflow capture area of the main propulsion source and increase an overall airflow capture area of the propulsion system. In the second mode, the auxiliary power source is operated by power extracted from the main propulsion source. The main propulsion source may include one or more low bypass ratio engines. The auxiliary power source may include one or more auxiliary thrust fans coupled at a plurality of locations on the aircraft.