Ecology valve fuel return system operable in fluid isolation during gas turbine engine shut-down

An ecology valve (EV) fuel return system for use in conjunction with a fuel supply system and a gas turbine engine (GTE) including at least a first fuel manifold, the EV fuel return system comprising:

• a housing assembly having a fuel return outlet and a first manifold inlet configured to be fluidly coupled to the fuel supply system and to the first fuel manifold, respectively;
• an EV piston slidably disposed within the housing assembly and movable between a fuel storage position and a fuel return position, the EV piston cooperating with the housing assembly to define a fuel storage chamber and an EV control chamber therein;
• and
• a fuel routing assembly fluidly coupled to the fuel storage chamber, the EV control chamber, the first manifold inlet, and the fuel return outlet, the fuel routing assembly configured to route:
• (i) from the fuel storage chamber to the fuel return outlet when the GTE is in a start-up mode, and (ii) from the EV control chamber and from the first manifold inlet into the fuel storage chamber when the GTE is in a shut-down mode.

A fuel control assembly for use in conjunction with a gas turbine engine (GTE) having at least a first fuel manifold, the fuel control assembly comprising:

• a fuel supply system configured to supply pressurized fuel to the first fuel manifold;
• and
• an ecology valve (EV) fuel return system, comprising:
• a housing assembly having a fuel return outlet and a first manifold inlet, the fuel return outlet fluidly coupled to the fuel supply system and the first manifold inlet configured to be fluidly coupled to the first fuel manifold;
• an EV piston slidably disposed within the housing assembly and movable between a fuel storage position and a fuel return position, the EV piston cooperating with the housing assembly to define a fuel storage chamber and an EV control chamber therein;
• and
• a fuel routing assembly fluidly coupled to the fuel storage chamber, the EV control chamber, the first manifold inlet, and the fuel return outlet, the fuel routing assembly configured to route fuel:
• (i) from the fuel storage chamber to the fuel return outlet when the GTE is in a start-up mode, and (ii) from the EV control chamber and from the first manifold inlet into the fuel storage chamber when the GTE is in a shut-down mode.