Compound engine assembly with bleed air

Patent metadata

Field	Value
Publication number	US-2020200077-A1
Application number	US-202016794806-A
Country	US
Kind code	A1
Filing date	Feb 19, 2020
Priority date	Jun 25, 2015
Publication date	Jun 25, 2020
Grant date	—

Abstract

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.

First claim

1 . A compound engine assembly for use as an auxiliary power unit for an aircraft, the compound engine assembly comprising:
an engine core including at least one internal combustion engine; a compressor having an outlet in fluid communication with an inlet of the engine core; 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; and a turbine section having an inlet in fluid communication with an outlet of the engine core, the turbine section configured to compound power with the engine core.

2 . The compound engine assembly as defined in claim 1 , wherein each of the at least one internal combustion engine includes a rotor sealingly and rotationally received within a respective internal cavity to provide rotating chambers of variable volume in the respective internal cavity, the rotor having three apex portions separating the rotating chambers and mounted for eccentric revolutions within the respective internal cavity, the respective internal cavity having an epitrochoid shape with two lobes.

3 . The compound engine assembly as defined in claim 1 , wherein the engine core has a shaft drivingly engaged to rotors of the compressor and of the turbine section.

4 . The compound engine assembly as defined in claim 1 , wherein the turbine section compounds power with the engine core through driving engagement between a shaft of the engine core and at least one rotor of the turbine section.

5 . The compound engine assembly as defined in claim 1 , wherein the turbine section includes at least one rotor engaged on a turbine shaft rotatable independently of a shaft of the engine core, the assembly further comprising a first generator in driving engagement with the shaft of the engine core, a second generator in driving engagement with the turbine shaft, and a power controller connected to the first and second generators and controlling power transfer between the first and second generators.

6 . The compound engine assembly as defined in claim 1 , wherein the turbine section includes a first stage turbine having an inlet in fluid communication with the outlet of the engine core, and a second stage turbine having an inlet in fluid communication with an outlet of the first stage turbine.

7 . The compound engine assembly as defined in claim 6 , wherein the first stage turbine is configured as an impulse turbine with a pressure-based reaction ratio having a value of at most 0.25, the second stage turbine having a higher reaction ratio than that of the first stage turbine.

8 . The compound engine assembly as defined in claim 1 , further comprising an inlet conduit in fluid communication with the inlet of the engine core and an outlet conduit in fluid communication with the outlet of the compressor, the inlet conduit and bleed conduit being both in fluid communication with the outlet conduit.

9 . The compound engine assembly as defined in claim 1 , wherein the bleed conduit is in fluid communication with the outlet of the compressor at least in part through an intercooler configured to reduce a temperature of compressed air circulating from the compressor to the bleed conduit.

10 . The compound engine assembly as defined in claim 1 , further comprising variable inlet guide vanes, a variable diffuser or a combination thereof at an inlet of the compressor.

11 . A compound engine assembly for use as an auxiliary power unit for an aircraft, the compound engine assembly comprising:
an engine core including at least one internal combustion engine in driving engagement with a common shaft; a generator in driving engagement with the common shaft to provide electrical power for the aircraft; a compressor having an outlet in fluid communication with an inlet of the engine core; a bleed conduit having an end configured for connection to a system of the aircraft, the bleed conduit being in fluid communication with the outlet of the compressor; a bleed air valve selectively opening and closing the fluid communication between the end of the bleed conduit and the outlet of the compressor; a first stage turbine having an inlet in fluid communication with an outlet of the engine core; and a second stage turbine having an inlet in fluid communication with an outlet of the first stage turbine; wherein at least one of the first and second stage turbines is configured to compound power with the engine core.

12 . The compound engine assembly as defined in claim 11 , wherein each of the at least one internal combustion engine includes a rotor sealingly and rotationally received within a respective internal cavity to provide rotating chambers of variable volume in the respective internal cavity, the rotor having three apex portions separating the rotating chambers and mounted for eccentric revolutions within the respective internal cavity, the respective internal cavity having an epitrochoid shape with two lobes.

13 . The compound engine assembly as defined in claim 11 , wherein the common shaft of the engine core is drivingly engaged to rotors of the compressor and of the first and second stage turbines.

14 . The compound engine assembly as defined in claim 11 , wherein the first and second stage turbines are both configured to compound power with the engine core and both in driving engagement with the compressor.

15 . The compound engine assembly as defined in claim 11 , wherein rotors of the first and second stage turbines and of the compressor are engaged on a turbine shaft rotatable independently of the common shaft of the engine core, and the generator is a first generator, the assembly further comprising a second generator in driving engagement with the turbine shaft, and a power controller connected to the first and second generators and controlling power transfer between the first and second generators.

16 . The compound engine assembly as defined in claim 11 , wherein the first stage turbine is configured as an impulse turbine with a pressure-based reaction ratio having a value of at most 0.25, the second stage turbine having a reaction ratio higher than that of the first stage turbine.

17 . The compound engine assembly as defined in claim 11 , further comprising an inlet conduit in fluid communication with the inlet of the engine core and an outlet conduit communicating with the outlet of the compressor, the inlet conduit and bleed conduit being both in fluid communication with the outlet conduit.

18 . The compound engine assembly as defined in claim 11 , wherein the bleed conduit is in fluid communication with the outlet of the compressor at least in part through an intercooler configured to reduce a temperature of compressed air circulating from the compressor to the bleed conduit.

19 . A method of providing compressed air and electrical power to an aircraft, the method comprising:
flowing compressed air from an outlet of a compressor simultaneously to an inlet of at least one internal combustion engine of a compound engine assembly and to a bleed conduit in communication with a pneumatic system of the aircraft; driving at least one generator providing electrical power to the aircraft with the at least one internal combustion engine; and providing electrical power to the aircraft with at least one turbine of the compound engin

Assignees

• Pratt & Whitney Canada

Inventors

• Ullyott Richard
• Jones Anthony
• Julien Andre
• Thomassin Jean

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• B64D41/00 Primary

  Power installations for auxiliary purposes · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title

• Y02T50/40

  Weight reduction · CPC title

• Y02T50/50

  On board measures aiming to increase energy efficiency · CPC title