An auxiliary power unit for an aircraft, having a compressor, an intercooler including first conduit(s) having an inlet in fluid communication with the compressor outlet and second conduit(s) configured for circulation of a coolant therethrough, an engine core having an inlet in fluid communication with an outlet of the first conduit(s), and a bleed conduit in fluid communication with the outlet of the first conduit(s) through a bleed air valve. The auxiliary power unit may include a generator in driving engagement with the shaft of the engine core to provide electrical power for the aircraft. A method of providing compressed air and electrical power to an aircraft is also discussed.

A compound engine assembly for use as an auxiliary power unit for an aircraft and including an engine core with internal combustion engine(s), a compressor having an outlet in fluid communication with an engine core inlet, a bleed conduit in fluid communication with the compressor outlet through a bleed air valve, and a turbine section having an inlet in fluid communication with the engine core outlet and configured to compound power with the engine core. The turbine section may include a first stage turbine having an inlet in fluid communication with the engine core outlet and a second stage turbine having an inlet in fluid communication the first stage turbine outlet. A method of providing compressed air and electrical power to an aircraft is also discussed.

A compound engine assembly with an inlet duct, a compressor, an engine core including at least one internal combustion engine, and a turbine section including a turbine shaft configured to compound power with the engine shaft. The turbine section may include a first stage turbine and a second stage turbine. The turbine shaft and the engine shaft are parallel to each other. The turbine shaft, the engine shaft and at least part of the inlet duct are all radially offset from one another. A method of driving a rotatable load of an aircraft is also discussed.

A rotary piston and cylinder device (1) comprising a rotor (2), a stator and a shutter disc (3), the rotor comprising a piston (5) which extends from the rotor into the cylinder space, the rotor and the stator together defining the cylinder space, the shutter disc passing through the cylinder space and forming a partition therein, and the disc comprising a slot (3a) which allows passage of the piston therethrough, and a surface of the rotor and a surface of the stator opposing each other forming a close-running surface pair, and at least one of the surfaces comprising an abradable coating (10) which is provided with a plurality of recess formations, and the recess formations are discontinuous from each other.

A pneumatic engine includes first and second pneumatic motors. Each motor has a stator, a rotor, and a gas flow path. The rotor is rotatably connected to the stator. The gas flow path is defined at least in part by the stator and the rotor, and extends from a gas inlet to a terminal gas outlet. The gas flow path has an expansion portion extending between the gas inlet and an intermediate gas outlet, and a compression portion extending between the intermediate gas outlet and the terminal gas outlet. The terminal gas outlet of the first pneumatic motor is fluidly connected upstream of the gas inlet of the second pneumatic motor.

A compound engine system includes a rotary engine with rotating chambers, a compressor section in successive communication with the rotating chambers, and a turbine section in successive communication with the rotating chambers. The turbine section has an output shaft. The output shaft and the engine shaft are drivingly engaged to each other and wherein the turbine section has a power output corresponding to from 20% to 35% of a total power output of the compound engine system. A method of compounding power in a compound engine system is also discussed.

A rotary internal combustion engine including a rotor assembly where at least a first and a second of the combustion chambers have unequal theoretical volumetric ratios. Also, a rotary internal combustion engine including first and second rotor assemblies where at least one of the combustion chambers of the first rotor assembly and at least one of the combustion chambers of the second rotor assembly have unequal effective volumetric compression ratios and/or unequal effective volumetric expansion ratios.

An engine assembly including an engine core including at least one internal combustion engine each including a rotor sealingly and rotationally received within a respective internal cavity to provide rotating chambers of variable volume in the respective internal cavity, a compressor having an outlet in fluid communication with an inlet of the engine core, a first intake conduit in fluid communication with an inlet of the compressor and with a first source of air, a second intake conduit in fluid communication with the inlet of the compressor and with a second source of air warmer than the first source of air, and a selector valve configurable to selectively open and close at least the fluid communication between the inlet of the compressor and the first intake conduit. A method of supplying air to a compressor is also discussed.

An engine assembly has an engine core comprising at least two stacks of rotary internal combustion engines drivingly connected to a common load. The engine further comprises a compressor section having an outlet in fluid communication with an inlet of the engine core, and a turbine section having an inlet in fluid communication with an outlet of the engine core.

A compound engine assembly with an engine core including at least one internal combustion engine, a compressor, and a turbine section where the turbine shaft is configured to compound power with the engine shaft. The turbine section may include a first stage turbine and a second stage turbine. The turbine shaft is rotationally supported by a plurality of bearings all located on a same side of the compressor rotor(s) and all located on a same side of the turbine rotor(s), for example all located between the compressor rotor(s) and the turbine rotor(s), such that the compressor rotor(s) and the turbine rotor(s) are cantilevered. A method of driving a rotatable load of an aircraft is also discussed.