Compound engine assembly with bleed air

An engine assembly for use as an auxiliary power unit for an aircraft, comprising:

• an engine core including at least one internal combustion engine, the engine core in driving engagement with an engine shaft;
• a generator drivingly engaged by the engine core via the engine shaft;
• a compressor having an outlet in fluid communication with an inlet of the engine core;
• a turbine section having an inlet in fluid communication with an outlet of the engine core, the turbine section in driving engagement with the compressor via a turbine shaft;
• a bleed conduit having an end configured for connection with a pneumatic system of the aircraft, the bleed conduit in fluid communication with the outlet of the compressor through a bleed air valve selectively opening and closing the fluid communication between the outlet of the compressor and the end of the bleed conduit configured for connection to the pneumatic system;
• an excess air duct in fluid communication with the outlet of the compressor, the excess air duct fluidly connected to the turbine section;
• and
• a heat exchanger having at least one first conduit in heat exchange relationship with at least one second conduit, the at least one first conduit fluidly connected to the excess air duct, the at least one second conduit fluidly connected to an outlet of the turbine section such that excess compressed air from the compressor is heated by combustion gases outputted by the turbine section.