Variable restriction of a secondary circuit of a fuel injector

1. A fuel injector for a turbine engine comprising:

a housing having an internal enclosure for pressurized fluid;

a fuel inlet formed on the housing, permitting delivery of a fuel supply to the fuel injector;

a scheduling valve disposed within the housing, configured for regulation of fuel flow from the fuel inlet in response to fuel pressure received at the fuel inlet;

a primary fuel circuit formed in the housing, receiving fuel from the scheduling valve;

a secondary fuel circuit formed in the housing, receiving fuel from the scheduling valve;

an auxiliary fuel circuit formed in the housing, receiving fuel from the scheduling valve;

an electrically-controlled valve in fluid communication with the auxiliary fuel circuit, adapted and configured to actively control fuel through the auxiliary fuel circuit in response to a control signal;

a fuel nozzle in fluid communication with and receiving fuel from the primary and secondary and auxiliary fuel circuits;

a primary outlet formed on the nozzle, in fluid communication with the primary fuel circuit; and

a secondary outlet formed on the nozzle, in fluid communication with the secondary fuel circuit and the auxiliary fuel circuit,

wherein the scheduling valve includes a valve spool, biased to a closed position by one or more biasing members, wherein the valve spool is configured to regulate flow from the inlet of the injector to each of the primary, secondary and auxiliary fuel circuits,

wherein the valve spool includes a scheduling surface configured to vary flow area through the secondary circuit based on position of the valve spool within the scheduling valve, and

wherein the valve spool includes a scheduling surface configured to vary flow area through the auxiliary circuit based on position of the valve spool within the scheduling valve.

2. The fuel injector of claim 1 , wherein the auxiliary fuel circuit branches off of the primary fuel circuit.

3. The fuel injector of claim 1 , wherein the auxiliary fuel circuit is an independent fuel circuit downstream from the scheduling valve.

4. The fuel injector of claim 1 , wherein activation of the electrically-controlled valve controls fuel flow rate through the auxiliary fuel circuit.

5. The fuel injector of claim 1 , wherein the electrically-controlled valve is a binary valve.

6. The fuel injector of claim 1 , wherein the electrically-controlled valve is a modulating valve.

7. The fuel injector of claim 1 , wherein the electrically-controlled valve is a motorized valve.

8. A fuel supply system for a turbine engine, comprising:

a single fuel manifold adapted to receive and distribute a fuel supply to a plurality of points of the turbine engine; and

a plurality of fuel injectors distributed around a periphery of the engine, adapted and configured to receive fuel from the single fuel manifold, at least one of the fuel injectors having:

a housing having an internal enclosure for pressurized fluid;

a fuel inlet formed on the housing, permitting delivery of fuel supply from the single fuel manifold to the fuel injector;

a scheduling valve disposed within the housing, configured for regulation of fuel flow from the fuel inlet in response to fuel pressure received at the fuel inlet;

a primary fuel circuit formed in the housing, receiving fuel from the scheduling valve;

a secondary fuel circuit formed in the housing, receiving fuel from the scheduling valve;

an auxiliary fuel circuit formed in the housing, receiving fuel from the scheduling valve;

an electrically-controlled valve in fluid communication with the auxiliary fuel circuit adapted and configured to actively control fuel through the auxiliary fuel circuit in response to a control signal;

a fuel nozzle in fluid communication with and receiving fuel from the primary, secondary and auxiliary fuel circuits;

a primary outlet formed on the nozzle, in fluid communication with the primary fuel circuit; and

a secondary outlet formed on the nozzle, in fluid communication with the secondary fuel circuit and the auxiliary fuel circuit,

wherein the scheduling valve includes a valve spool, biased to a closed position by one or more biasing members, wherein the valve spool is configured to regulate flow from the inlet of the injector to each of the primary, secondary and auxiliary fuel circuits,

wherein the valve spool includes a scheduling surface configured to vary flow area through the secondary circuit based on position of the valve spool within the scheduling valve, and

wherein the valve spool includes a scheduling surface configured to vary flow area through the auxiliary circuit based on position of the valve spool within the scheduling valve.

9. The fuel supply system of claim 8 , further comprising:

at least one passive fuel injector, receiving fuel from the single fuel manifold.

10. The fuel supply system of claim 9 , wherein the at least one passive fuel injector includes only one nozzle.

11. The fuel supply system of claim 8 , further comprising:

a metering valve adapted and configured to receive a fuel supply from a fuel pump, and output the fuel to the single manifold.

12. The fuel supply system of claim 8 , further comprising a controller electrically connected to the electrically-controlled valve on at least one fuel injector for individual control thereof.

13. The fuel supply system of claim 8 , further comprising a controller electrically connected to each of the electrically-controlled valves of a plurality of fuel injectors for ganged control thereof.