A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor configured to drive a motor shaft. A transmission system is connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power. A first lubrication/coolant system is connected for circulating a first lubricant/coolant fluid through the heat engine. A second lubricant/coolant system in fluid isolation from the first lubrication/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor.

A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor configured to drive a motor shaft. A transmission system is connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power. A first lubrication/coolant system is connected for circulating a first lubricant/coolant fluid through the heat engine. A second lubricant/coolant system in fluid isolation from the first lubrication/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor.

A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor configured to drive a motor shaft. A transmission system is connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power. A first lubrication/coolant system is connected for circulating a first lubricant/coolant fluid through the heat engine. A second lubricant/coolant system in fluid isolation from the first lubrication/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor.

A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor configured to drive a motor shaft. A transmission system is connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power. A first lubrication/coolant system is connected for circulating a first lubricant/coolant fluid through the heat engine. A second lubricant/coolant system in fluid isolation from the first lubrication/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor.

An oil recovery structure for cooling a motor includes a rotor connected to a rotary shaft, a stator disposed on the rotor, a housing surrounding the rotor and the stator, and an oil housing disposed on the housing, in which the oil housing includes a first inlet through which the oil is introduced from a space defined on one side of the rotor, a second inlet through which the oil is introduced from a reducer connected to the rotary shaft, and a discharging port discharging the oil inside the oil housing to an oil filter.

An oil recovery structure for cooling a motor includes a rotor connected to a rotary shaft, a stator disposed on the rotor, a housing surrounding the rotor and the stator, and an oil housing disposed on the housing, in which the oil housing includes a first inlet through which the oil is introduced from a space defined on one side of the rotor, a second inlet through which the oil is introduced from a reducer connected to the rotary shaft, and a discharging port discharging the oil inside the oil housing to an oil filter.

A method for cooling a hybrid electric aircraft propulsion system comprises transporting a coolant through a two-phase pumped loop (TPPL) in thermal contact with an electrical machine and a plurality of power modules to be cooled, where the TPPL includes: a parallel arrangement of cold plates; an evaporator; a condenser; a first control valve; a liquid receiver; and a pump. A sensor positioned upstream of the cold plates, and in some cases upstream of the liquid receiver, measures pressure and/or temperature of a return stream of the coolant and transmits measurement data to a first controller electrically connected to the first control valve. The first controller regulates flow of a first liquid stream through the first control valve based on the pressure and/or temperature measured by the sensor, thereby keeping the return stream at a temperature within a predetermined temperature range.

A method for cooling a hybrid electric aircraft propulsion system comprises transporting a coolant through a two-phase pumped loop (TPPL) in thermal contact with an electrical machine and a plurality of power modules to be cooled, where the TPPL includes: a parallel arrangement of cold plates; an evaporator; a condenser; a first control valve; a liquid receiver; and a pump. A sensor positioned upstream of the cold plates, and in some cases upstream of the liquid receiver, measures pressure and/or temperature of a return stream of the coolant and transmits measurement data to a first controller electrically connected to the first control valve. The first controller regulates flow of a first liquid stream through the first control valve based on the pressure and/or temperature measured by the sensor, thereby keeping the return stream at a temperature within a predetermined temperature range.

An apparatus and method relating to a generator comprising a housing defining an interior and fluidly separating the interior from surrounding ambient air, at least one of a rotor or stator located within the housing, a cooling circuit passing through at least a portion of the housing to cool the interior and recirculating a coolant having a density greater than the ambient air, and a jet pump having a motive fluid conduit fluidly coupled to the cooling circuit, a transport fluid circuit fluidly coupled to the ambient air.

An apparatus and method relating to a generator comprising a housing defining an interior and fluidly separating the interior from surrounding ambient air, at least one of a rotor or stator located within the housing, a cooling circuit passing through at least a portion of the housing to cool the interior and recirculating a coolant having a density greater than the ambient air, and a jet pump having a motive fluid conduit fluidly coupled to the cooling circuit, a transport fluid circuit fluidly coupled to the ambient air.