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.

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 engine core including at least one internal combustion engine, a turbine section, and a compressor having an outlet in fluid communication with an inlet of the engine core. A casing is connected to the turbine section, the compressor and the engine core. A mount cage is connected to mounts attached to the casing between the compressor and a hot zone including the turbine section and the engine core. The mount cage includes a plurality of struts all extending from the mounts away from the turbine section and engine core. The casing may be a gearbox module casing through which the turbine shaft in engaged with the engine shaft. The mount cage may be completely contained within an axial space with the turbine section and engine core being located outside of the axial space.

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.

A compound engine assembly including a common air conduit having an inlet in fluid communication with ambient air, a compressor, at least one internal combustion engine having an inlet in fluid communication with an outlet of the compressor, a turbine section having an inlet in fluid communication with an outlet of the at least one internal combustion engine, the turbine section configured to compound power with the at least one internal combustion engine, and at least one heat exchanger in fluid communication with the common air conduit, each of the at least one heat exchanger configured to circulate a fluid of the engine assembly in heat exchange relationship with an airflow from the common air conduit circulating therethrough. The compressor has an inlet in fluid communication with the common air conduit upstream of the at least one heat exchanger. The internal combustion engine may be a reciprocating engine.

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 auxiliary power unit having internal combustion engine(s) in driving engagement with an engine shaft, a generator having a generator shaft drivingly engaged to the engine shaft, a compressor having an outlet in communication with the internal combustion engine inlet, and a turbine having an inlet in communication with the internal combustion engine outlet. The turbine may be a first stage turbine, and the assembly may include a second stage turbine having an inlet in communication with the first stage turbine outlet. A method of providing electrical power to an aircraft is also discussed.

A compound engine assembly with an inlet duct having an inlet surrounded by an inlet lip including at least one conduit extending therethrough, a compressor, an engine core including at least one internal combustion engine, a turbine section having a turbine shaft in driving engagement with the engine shaft, and an exhaust conduit providing a fluid communication between the outlet of the turbine section and the conduit(s) of the inlet lip. An exhaust duct and ant exhaust conduit providing a fluid communication between the outlet of the turbine section and the exhaust duct may also be provided. The internal combustion engine(s) may be rotary engine(s). A method of driving a rotatable load of an aircraft is also discussed.

An engine assembly including an engine core with at least one internal combustion engine, a first casing, a turbine module including a second casing located outside of the first casing, and a compressor module including a third casing located outside of the first and second casings. The turbine shaft extends into the first casing, is rotationally supported by a bearings all contained within the first casing, and is free of rotational support within the second casing. The first casing may be a gearbox module casing through which the turbine shaft is in driving engagement with the engine shaft. A method of driving a rotatable load of an aircraft, and an engine assembly with a rotary engine core, a gearbox module with a first casing, and a second module including a second casing located outside of the first casing and detachably connected to the first casing are also discussed.

An engine assembly including an internal combustion engine, an impulse turbine, and an exhaust pipe providing fluid communication between the exhaust port of the internal combustion engine and the flow path of the turbine. The exhaust pipe terminates in a nozzle. A ratio Vp/Vd between the pipe volume Vp and the displacement volume Vd of the internal combustion engine is at most 1.5. A minimum value of a cross-sectional area of the exhaust pipe is defined at the nozzle. In one embodiment, a ratio An/Ae between the minimum cross-sectional area An and the cross-sectional area Ae of the exhaust port of the internal combustion engine is at least 0.2. A method of compounding at least one internal combustion engine is also discussed.