Rotary engine and method of combusting fuel

Patent metadata

Field	Value
Publication number	US-11215110-B2
Application number	US-201816177752-A
Country	US
Kind code	B2
Filing date	Nov 1, 2018
Priority date	Oct 10, 2017
Publication date	Jan 4, 2022
Grant date	Jan 4, 2022

Abstract

A method of combusting fuel, e.g. heavy fuel, in a rotary engine, including injecting a main quantity of fuel directly into a combustion chamber to form a first fuel-air mixture having a first air-fuel equivalence ratio λ higher than 1, injecting a pilot quantity of fuel into a pilot subchamber to form a second fuel-air mixture having a second air-fuel equivalence ratio λ smaller than the first air-fuel equivalence ratio, igniting the second fuel-air mixture within the pilot subchamber, using the ignited second fuel-air mixture from the pilot subchamber to ignite the first fuel-air mixture, and injecting a supplemental quantity of fuel directly into the combustion chamber after igniting the first fuel-air mixture, upstream of an exhaust port of the rotary engine with respect to a direction of rotation of the rotor. A rotary engine with interburner fuel injector is also discussed.

First claim

The invention claimed is:

1. A rotary engine comprising:
a rotor sealingly received within an internal cavity of a housing to define a plurality of combustion chambers having a variable volume;
an intake port and an exhaust port defined through the housing and in fluid communication with each of the combustion chambers in a successive manner;
a pilot subchamber stationary relative to the housing and in fluid communication with each of the combustion chambers in a successive manner, a volume of the pilot subchamber being at least 0.5% and at most 3.5% of a displacement volume defined as a difference between maximum and minimum volumes of one of the combustion chambers;
a main fuel injector in direct fluid communication with each of the combustion chambers in a successive manner, the main fuel injector being located downstream of the intake port and upstream of the pilot subchamber with respect to a direction of rotation of the rotor;
a pilot fuel injector in fluid communication with the pilot subchamber;
an ignition source in heat exchange relationship with the pilot subchamber; and
an interburner fuel injector in direct fluid communication with each of the combustion chambers in a successive manner, the interburner fuel injector being located downstream of the pilot subchamber and upstream of the exhaust port.

2. The rotary engine as defined in claim 1 , further comprising a source of heavy fuel in fluid communication with the main fuel injector, the pilot fuel injector and the interburner fuel injector.

3. The rotary engine as defined in claim 1 , wherein each of the combustion chamber is in simultaneous fluid communication with the pilot subchamber and the interburner fuel injector during a respective portion of a revolution of the rotor.

4. The rotary engine as defined in claim 1 , wherein the interburner fuel injector is spaced from the pilot subchamber a distance sufficient to prevent the combustion chambers from simultaneously communicating with the pilot subchamber and the interburner fuel injector.

5. The rotary engine as defined in claim 1 , wherein the ignition source is a glow plug.

6. The rotary engine as defined in claim 1 , wherein the rotary engine is a Wankel engine, the internal cavity having a profile defining two lobes, the rotor having three circumferentially-spaced apex portions in sealing engagement with a peripheral wall of the housing and separating the combustion chambers.

7. A compound engine assembly including the rotary engine as defined in claim 1 , a compressor in fluid communication with the intake port of the rotary engine, and a turbine in fluid communication with the exhaust port of the rotary engine, the turbine having a turbine shaft drivingly engaged with an engine shaft drivingly engaged to the rotor.

8. The rotary engine as defined in claim 1 , wherein the pilot subchamber has a circular cross-section.

9. The rotary engine as defined in claim 1 , wherein the pilot subchamber is in fluid flow communication each of the combustion chambers in a successive manner via at least one opening, the at least one opening defining a restriction.

10. The rotary engine as defined in claim 1 , wherein the pilot subchamber has a shape forming a reduced cross-section adjacent an opening connecting the pilot subchamber to each of the combustion chambers in a successive manner.

11. The rotary engine as defined in claim 1 , wherein the pilot subchamber is defined by an insert received within the housing.

12. The rotary engine as defined in claim 11 , wherein the insert is made of a material having a greater heat resistance than that of the housing.

13. A rotary engine comprising:
a rotor sealingly received within an internal cavity of a housing to define a plurality of combustion chambers having a variable volume;
an intake port and an exhaust port defined through the housing and in fluid communication with each of the combustion chambers in a successive manner;
a pilot subchamber stationary relative to the housing and in fluid communication with each of the combustion chambers in a successive manner, a volume of the pilot subchamber being from 5% to 25% of a combustion volume defined as a sum of a minimum volume of one of the combustion chambers and a volume of the pilot subchamber;
a main fuel injector in direct fluid communication with each of the combustion chambers in a successive manner, the main fuel injector being located downstream of the intake port and upstream of the pilot subchamber with respect to a direction of rotation of the rotor;
a pilot fuel injector in fluid communication with the pilot subchamber;
an ignition source in heat exchange relationship with the pilot subchamber; and
an interburner fuel injector in direct fluid communication with each of the combustion chambers in a successive manner, the interburner fuel injector being located downstream of the pilot subchamber and upstream of the exhaust port.

14. The rotary engine as defined in claim 13 , further comprising a source of heavy fuel in fluid communication with the main fuel injector, the pilot fuel injector and the interburner fuel injector.

15. The rotary engine as defined in claim 13 , wherein each of the combustion chamber is in simultaneous fluid communication with the pilot subchamber and the interburner fuel injector during a respective portion of a revolution of the rotor.

16. The rotary engine as defined in claim 13 , wherein the interburner fuel injector is spaced from the pilot subchamber a distance sufficient to prevent the combustion chambers from simultaneously communicating with the pilot subchamber and the interburner fuel injector.

17. The rotary engine as defined in claim 13 , wherein the ignition source is a glow plug.

18. The rotary engine as defined in claim 13 , wherein the rotary engine is a Wankel engine, the internal cavity having a profile defining two lobes, the rotor having three circumferentially-spaced apex portions in sealing engagement with a peripheral wall of the housing and separating the combustion chambers.

19. The rotary engine as defined in claim 13 , wherein the pilot subchamber has a circular cross-section.

Assignees

• Pratt & Whitney Canada

Inventors

• Thomassin Jean
• Julien Andre
• Dussault Serge

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02D41/3094

  the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder · CPC title

• F02B19/1014

  design parameters, e.g. volume, torch passage cross sectional area, length, orientation, or the like · CPC title

• F02B2053/005

  Wankel engines · CPC title

• F02B53/10

  Fuel supply; Introducing fuel to combustion space · CPC title