Figure 7-25.Fuel system.
Maximum Fuel Solenoid Valve. The
Start Fuel Solenoid Valve. The star t
maximum fuel solenoid valve is also normally closed.
fuel solenoid v alv e is a normally closed v alv e.
It assists in fuel scheduling for the start acceleration
It is en er g ized to th e open position by th e ESU
control. At 90 percent of rated engine speed, plus 2
to supply fuel to the start fuel nozzle. At 90
seconds, is energized. It bypasses the acceleration
per c ent of r ated eng ine speed, the v alv e is de-
orifice and the valve allows maximum fuel flow for
ener g ized. In the de-ener g ized position, the
governing at rated engine speeds and loads.
v alv e shuts off fuel flow to the star t fuel
nozzle.
START FUEL NOZZLE. The start fuel
Main Fuel Solenoid Valve. The main fuel
nozzle is contained in a special fitting located on the
left side of the combuster. Fuel to this nozzle is
solenoid valve is a normally closed valve. It is
controlled by the start fuel solenoid valve. Fuel that
energized open by the ESU. When open, this valve
is atomized by the nozzle is ignited by the igniter
allows fuel to flow to the fuel manifold assembly. De-
plug. The plug is located close to and directly in line
energizing this valve produces a normal shutdown of
with the start fuel nozzle.
the APU.
