COMPOUND CYCLE ENGINE

• US 20150275749A1
• Filed: 06/16/2015
• Published: 10/01/2015
• Est. Priority Date: 07/20/2012
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: THOMASSIN, Jean
• Granted Patent: US 9,926,843 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01C 1/22 of internal-axis type with equidirectional movement of co-operating members at the points of engagement, or with one of the co-operating members being stationary, the inner member having more teeth or tooth- equivalents than the outer member
• CPC Class Codes: F01C 11/002 of similar working principle
• CPC Class Codes: F01C 11/008 and of complementary function, e.g. internal combustion engine with supercharger
• CPC Class Codes: F02B 41/10 in exhaust turbines use of exhaust turbines for charging F02B37/00
• CPC Class Codes: F02B 53/02 Methods of operating
• CPC Class Codes: F02B 63/00 Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices of rotary-piston or oscillating-piston engines F02B53/14
• CPC Class Codes: F02C 5/00 Gas-turbine plants characterised by the working fluid being generated by intermittent combustion
• CPC Class Codes: F02C 6/12 Turbochargers, i.e. plants for augmenting mechanical power output of internal-combustion piston engines by increase of charge pressure
• CPC Class Codes: F02C 6/20 Adaptations of gas-turbine plants for driving vehicles
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A compound cycle engine having at least one rotary unit defining an internal combustion engine, a first stage turbine in proximity of each unit, and a turbocharger is discussed. The exhaust port of each rotary unit is in fluid communication with the flowpath of the first stage turbine upstream of its rotor. The rotors of the first stage turbine and of each rotary unit drive a common load. The outlet of the compressor of the turbocharger is in fluid communication with the inlet port of each rotary unit, and the inlet of the second stage turbine of the turbocharger is in fluid communication with the flowpath of the first stage turbine downstream of its rotor. The first stage turbine has a lower reaction ratio than that of the second stage turbine. A method of compounding at least one rotary engine is also discussed.

Claims

1. A compound cycle engine comprising:

at least one rotary unit each defining an internal combustion engine including an engine rotor sealingly and rotationally received within a respective housing, each housing defining an inlet port and an exhaust port;

a first stage turbine in proximity of the at least one rotary unit, the first stage turbine including a flowpath and a turbine rotor having a circumferential array of blades extending across the flowpath, the turbine rotor of the first stage turbine and the engine rotor of each of the at least one rotary unit being in driving engagement with a common shaft; and

a turbocharger including a compressor and a second stage turbine in driving engagement with one another;

wherein;

an outlet of the compressor is in fluid communication with the inlet port of each housing;

the exhaust port of each housing is in fluid communication with a first portion of the flowpath of the first stage turbine, the first portion of the flowpath being located upstream of the circumferential array of blades of the first stage turbine;

an inlet of the second stage turbine is in fluid communication with a second portion of the flowpath of the first stage turbine, the second portion of the flowpath being located downstream of the circumferential array of blades of the first stage turbine; and

the first stage turbine has a lower reaction ratio than that of the second stage turbine.

2. The compound cycle engine as defined in claim 1, wherein the reaction ratio of the first stage turbine is a pressure-based reaction ratio having a value of at most 0.25.

3. The compound cycle engine as defined in claim 1, wherein the reaction ratio of the first stage turbine is a pressure-based reaction ratio having a value of at most 0.1 and the second stage turbine has a pressure-based reaction ratio having a value of at least 0.25.

4. The compound cycle engine as defined in claim 1, wherein the reaction ratio of the first stage turbine is a pressure-based reaction ratio having a value of at most 0.1 and the second stage turbine has a pressure-based reaction ratio having a value of at least 0.25.

5. The compound cycle engine as defined in claim 1, wherein each of the at least one rotary unit is a Wankel engine.

6. The compound cycle engine as defined in claim 1, wherein the flowpath of the first stage turbine is an axial flowpath.

7. The compound cycle engine as defined in claim 1, wherein the compressor and the second stage turbine are in driving engagement with one another through a turbocharger shaft rotatable independently of the common shaft.

8. The compound cycle engine as defined in claim 1, wherein the compressor and the second stage turbine are in driving engagement with the common shaft.

9. The compound cycle engine as defined in claim 1, wherein the compressor and the second stage turbine are in driving engagement with one another through a turbocharger shaft, and wherein the common shaft is an output shaft having a different axis than that of the turbocharger shaft, the compressor and the second stage turbine each including at least one radial impeller.

10. The compound cycle engine as defined in claim 1, wherein the common shaft is an output shaft connected to the engine rotor of each of the at last one rotary unit, the first stage turbine being drivingly engaged to the output shaft through a transmission.

11. The compound cycle engine as defined in claim 1, further comprising common rail fuel injectors for each of the at least one rotary unit, and a heavy fuel source in communication with the fuel injectors

12. A compound cycle engine comprising:

at least one rotary engine each having an engine rotor sealingly and rotationally received within a respective housing having an inlet port and an exhaust port, the engine rotor of each of the at least one rotary engine being drivingly engaged to a common shaft;

a first stage turbine in proximity of the at least one rotary engine and having a turbine rotor drivingly engaged to the common shaft;

a respective exhaust pipe providing fluid communication between each exhaust port and an inlet of the first stage turbine;

a turbocharger including a compressor and a second stage turbine drivingly engaged to one another;

an inlet duct providing fluid communication between an outlet of the compressor and the inlet port of each of the at least one rotary engine; and

a turbine pipe providing fluid communication between an outlet of the first stage turbine and an inlet of the second stage turbine;

wherein the first stage turbine has a lower reaction ratio than that of the second stage turbine.

13. The compound cycle engine as defined in claim 12, wherein the reaction ratio of the first stage turbine is a pressure-based reaction ratio having a value of at most 0.25.

14. The compound cycle engine as defined in claim 12, wherein the reaction ratio of the first stage turbine is a pressure-based reaction ratio having a value of at most 0.1 and the second stage turbine has a pressure-based reaction ratio having a value of at least 0.25.

15. The compound cycle engine as defined in claim 12, wherein the reaction ratio of the first stage turbine is a pressure-based reaction ratio having a value of at most 0.1 and the second stage turbine has a pressure-based reaction ratio having a value of at least 0.25.

16. The compound cycle engine as defined in claim 12, wherein the compressor and the second stage turbine are in driving engagement with one another through a turbocharger shaft rotatable independently of the common shaft.

17. The compound cycle engine as defined in claim 12, wherein the compressor and the second stage turbine are in driving engagement with the common shaft.

18. The compound cycle engine as defined in claim 12, wherein the turbine rotor of the first stage turbine is an axial rotor.

19. The compound cycle engine as defined in claim 12, wherein each of the at least one rotary engine is a Wankel engine.

20. The compound cycle engine as defined in claim 12, further comprising common rail fuel injectors for each of the at least one rotary engine, and a heavy fuel source in communication with the fuel injectors.

21. A method of compounding at least one rotary engine, the method comprising:

drivingly engaging a second stage turbine and a compressor in a turbocharger;

defining a fluid communication between an outlet of the compressor and an inlet port of each of the at least one rotary engine;

defining a fluid communication between an exhaust port of each of the at least one rotary engine and an inlet of a first stage turbine, including directing the fluid communication onto blades of a turbine rotor of the first stage turbine, the first stage turbine having a lower reaction ratio than that of the second stage turbine;

defining a fluid communication between an outlet of the first stage turbine and an inlet of the second stage turbine of the turbocharger; and

drivingly engaging an engine rotor of each rotary engine and the rotor of the first stage turbine to a common shaft.

22. The method as defined in claim 21, further comprising providing fluid communication between a source of heavy fuel and each of the at least one rotary engine.