COMPOUND ENGINE ASSEMBLY WITH EXHAUST PIPE NOZZLE

摘要

A compound engine assembly with at least one rotary internal combustion engine, an impulse turbine, and an exhaust pipe for each internal combustion engine providing fluid communication between the exhaust port of the respective internal combustion engine and the flow path of the turbine. Each exhaust pipe terminates in a nozzle. For each exhaust pipe, a ratio Vp/Vd between the pipe volume Vp and the displacement volume Vd of the respective internal combustion engine is at most 1.5. A minimum value of a cross-sectional area of each 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 respective internal combustion engine is at least 0.2. A method of compounding at least one rotary engine is also discussed.

主权项

1. A compound engine assembly comprising:
an engine core including at least one internal combustion engine, each internal combustion engine defining an internal cavity and including a rotor sealingly and rotationally received within the internal cavity to provide rotating chambers of variable volume in the internal cavity, the volume of each of the rotating chambers varying between a minimum volume and a maximum volume with a difference between the maximum and minimum volumes defining a displacement volume Vd, each internal combustion engine having an inlet port and an exhaust port in communication with the internal cavity; a turbine configured as an impulse turbine having a pressure based reaction ratio of at most 0.25, the turbine including a rotor including a circumferential array of rotor blades extending across a flow path; and an exhaust pipe for each internal combustion engine, each exhaust pipe having a pipe volume Vp, each exhaust pipe providing fluid communication between the exhaust port of a respective one of the at least one internal combustion engine and the flow path of the turbine, each exhaust pipe terminating in a nozzle communicating with a portion of the flow path located upstream of the rotor blades; wherein for each exhaust pipe, a ratio Vp/Vd between the pipe volume Vp and the displacement volume Vd of the respective one of the at least one internal combustion engine is at most 1.5; and wherein a minimum value of a cross-sectional area of each exhaust pipe is defined at the nozzle.