Rotary engine and method of combusting fuel

Patent metadata

Field	Value
Publication number	US-10145291-B1
Application number	US-201715729043-A
Country	US
Kind code	B1
Filing date	Oct 10, 2017
Priority date	Oct 10, 2017
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

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 method of combusting fuel in a rotary engine, the method comprising:
injecting a main quantity of the fuel directly into a combustion chamber of the rotary engine to form a first fuel-air mixture within the combustion chamber, the first fuel-air mixture having a first air-fuel equivalence ratio λ higher than 1;
injecting a pilot quantity of the fuel into a pilot subchamber to form a second fuel-air mixture within the pilot subchamber, the 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
after igniting the first fuel-air mixture, injecting a supplemental quantity of the fuel directly into the combustion chamber, the supplemental quantity being injected upstream of an exhaust port of the rotary engine with respect to a direction of rotation of the rotor.

2. The method as defined in claim 1 , wherein the fuel is heavy fuel.

3. The method as defined in claim 1 , wherein the supplemental quantity of fuel is injected while combustion of the first fuel-air mixture is active.

4. The method as defined in claim 1 , further comprising feeding compressed air into the combustion chamber before injecting the main quantity.

5. The method as defined in claim 1 , further comprising feeding exhaust from the exhaust port of the rotary engine to a turbine, and compounding power from a turbine shaft of the turbine with power from an engine shaft drivingly engaged to the rotor.

6. The method as defined in claim 1 , wherein the supplemental quantity is injected while the combustion chamber communicates with the pilot subchamber.

7. The method as defined in claim 1 , wherein the supplemental quantity is injected after a communication between the combustion chamber and the pilot subchamber is closed.

8. The method as defined in claim 1 , wherein the second air-fuel equivalence ratio is at most 1.

9. The method as defined in claim 1 , wherein the first air-fuel equivalence ratio of the first fuel-air mixture formed by the main quantity is at least 1.67.

10. The method as defined in claim 1 , wherein the first air-fuel equivalence ratio of the first fuel-air mixture formed by the main quantity is at least 2.

11. The method as defined in claim 10 , wherein the first air-fuel equivalence ratio of the first fuel-air mixture formed by the main quantity is at most 2.3.

12. The method as defined in claim 1 , wherein igniting the second fuel-air mixture is performed with a glow plug or with hot walls of the pilot subchamber.

13. The method as defined in claim 1 , wherein the main quantity is greater than the supplemental quantity and the supplemental quantity is greater than the pilot quantity.

14. The method as defined in claim 13 , wherein a sum of the pilot quantity, main quantity and supplemental quantity defines a total quantity, and wherein:
injecting the pilot quantity includes injecting from 2% to 10% of the total quantity into the pilot subchamber;
injecting the main quantity includes injecting at least 50% of the total quantity into the combustion chamber; and
injecting the supplemental quantity includes injecting from 10 to 40% of the total quantity into the combustion chamber.

15. The method as defined in claim 14 , wherein:
injecting the pilot quantity includes injecting about 5% of the total quantity into the pilot subchamber;
injecting the main quantity includes injecting about 75% of the total quantity into the combustion chamber; and
injecting the supplemental quantity includes injecting about 20% of the total quantity into the combustion chamber.

Assignees

• Pratt & Whitney Canada

Inventors

• Thomassin Jean
• Julien Andre
• Dussault Serge

Classifications

• 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

• F02B19/1023 Primary

  pre-combustion chamber and cylinder being fed with fuel-air mixture(s) · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title

• F02B9/08

  with incandescent chambers · CPC title