Fuel injectors with torch ignitors

1. A fuel injector comprising:

a fuel nozzle configured to issue a spray of fuel from a fuel outlet in a downstream direction along an injection axis, the fuel nozzle including a nozzle body that defines a main flow passage therethrough;

an injection fuel line in fluid communication with the fuel nozzle to supply fuel to the fuel nozzle; and

a torch ignitor with a flame outlet opening into the main flow passage of the fuel nozzle for issuing flame into the main flow passage, wherein the flame outlet meets the main flow passage at a position that is downstream of the fuel outlet with respect to the downstream direction along the injection axis, wherein the torch ignitor includes a torch wall defining a combustion chamber therein, wherein the combustion chamber is connected to outlet flame through the flame outlet passing out of the torch wall and into the main flow passage of the fuel nozzle, wherein the injection fuel line and the combustion chamber of the torch ignitor define a feed arm that extends perpendicular relative to the injection axis of the fuel nozzle.

2. The fuel injector as recited in claim 1 , wherein the main flow passage defines a main outlet for flame from the torch ignitor, and wherein the main outlet for flame is radially bigger than the fuel outlet with respect to the injection axis.

3. The fuel injector as recited in claim 1 , wherein the torch ignitor includes:

a torch fuel injector mounted to the torch wall to issue fuel into the combustion chamber; and

at least one ignitor mounted to the torch wall, positioned to ignite fuel issued from the torch fuel injector.

4. The fuel injector as recited in claim 3 , wherein the combustion chamber is connected to the flame outlet by a flame tube.

5. The fuel injector as recited in claim 4 , wherein the flame tube and flame outlet are oriented tangential relative to the injection axis to swirl flame from the combustion chamber around the main flow passage of the fuel nozzle.

6. The fuel injector as recited in claim 1 , wherein the fuel nozzle includes an upstream air swirler of the main flow passage, the upstream air swirler defining a plurality of passages configured to impart swirl on a flow of air flowing therethrough.

7. The fuel injector as recited in claim 6 , wherein the plurality of passages of the upstream air swirler are upstream of the flame outlet with respect to the downstream direction along the injection axis.

8. The fuel injector as recited in claim 6 , wherein the fuel nozzle includes a heat shield outboard of the nozzle body, with an insulation gap defined between the heat shield and the nozzle body.

9. The fuel injector as recited in claim 8 , wherein the injection fuel line passes through the heat shield and nozzle body at an upstream end of the fuel nozzle.

10. The fuel injector as recited in claim 8 , wherein the torch ignitor passes through the heat shield and nozzle body.

11. The fuel injector as recited in claim 8 , wherein a downstream air swirler is defined by a circumferential array of radial passages through the heat shield and nozzle body at a position downstream of the flame outlet with respect to the downstream direction along the injection axis.

12. The fuel injector as recited in claim 1 , wherein the fuel nozzle includes a pressure atomizer in fluid communication with the fuel outlet at an upstream end of the nozzle body.

13. The fuel injector as recited in claim 1 , wherein the fuel nozzle incudes an air blast atomizer in fluid communication with the fuel outlet in an upstream end of the nozzle body.

14. The fuel injector as recited in claim 1 , wherein the injection fuel line is thermally isolated from the torch ignitor.

15. The fuel injector as recited in claim 1 , wherein the nozzle body is conical and opens in the downstream direction along the injection axis.

16. The fuel injector as recited in claim 1 , wherein the nozzle body is cylindrical.

17. A system comprising:

an engine case;

a combustor within the engine case;

a plurality of fuel injectors connecting from outside the engine case to the combustor to issue fuel and air into the combustor for combustion, wherein each of the fuel injectors in the plurality of fuel injectors includes:

a fuel nozzle connected to the combustor to issue a spray of fuel from a fuel outlet in a downstream direction along an injection axis, the fuel nozzle including a nozzle body that defines a main flow passage therethrough;

an injection fuel line in fluid communication with the fuel nozzle to supply fuel to the fuel nozzle; and

a torch ignitor with a flame outlet opening into the main flow passage of the fuel nozzle for issuing flame into the main flow passage, wherein the flame outlet meets the main flow passage at a position that is downstream of the fuel outlet with respect to the downstream direction along the injection axis, wherein the torch ignitor includes a torch wall defining a combustion chamber therein, wherein the combustion chamber is connected to outlet flame through the flame outlet passing out of the torch wall and into the main flow passage of the fuel nozzle, wherein the injection fuel line and the combustion chamber of the torch ignitor define a feed arm that extends perpendicular relative to the injection axis of the fuel nozzle.

18. The system as recited in claim 17 , wherein the fuel injectors of the plurality of fuel injectors are oriented tangential relative to a main combustor axis of the combustor.

19. The system as recited in claim 17 , wherein the fuel injectors of the plurality of fuel injectors are oriented radially inward relative to a main combustor axis of the combustor.