LESSON # 3 Flashcards
Fuel from the LP Fuel filter passes to the (?) depending on RPM and FCU in the region of 600-800 psi. This HP fuel is then fed to the fuel control unit (FCU).
HP Pump/ High Pressure Pump
The (?) will meter the engines fuel requirements based upon a given set of conditions at any given time.
FUEL CONTROL UNIT (FCU)
Engines fuel requirements based upon a given set of conditions at any given time:
A. Throttle position.
B. Ambient Pressure (Pamb)
C. Ambient Temperature (T12)
D. HP Compressor RPM (N2)
E. Compressor Discharge Pressure (CDP)
Fuel in excess of that required is returned to the (?) of the HP pump.
inlet side
Metered fuel is then fed to the (?) via a throttles and HP cock.
flowmeter
The (?) can be a combined throttle and HP cock
lever or separate levers.
Fuel Control Operating Levers
The position of the (?) determines the power required.
Throttle Lever
The (?) controls the supply of fuel from the FCU to the burners, when closed the engine will be shut down, when open fuel will be available to the burners.
HP Shutoff Cock/ High Pressure Shutoff Cock
2 TYPES OF HEAT EXCHANGER
- FUEL/AIR HEAT EXCHANGER
- FUEL/OIL HEAT EXCHANGER
Similar to the heat exchanger used to heat the fuel, this heat exchanger will use the HP fuel supply to cool the engine oil.
FUEL/OIL HEAT EXCHANGER
Prevent fuel flowing to the burners during the starting phase until such time as fuel pressure is sufficient to give good atomisation of the fuel thus ensuring good light-up.
PRESSURISING AND DUMP VALVE
Allow sufficient pressure to build up within the Fuel Control Unit (FCU) servo/hydraulic control systems ensuring correct metering of fuel supply is achieved during starting.
PRESSURISING AND DUMP VALVE
Enable a rapid dump of fuel remaining in the pipelines to the burners on shutdown.
PRESSURISING AND DUMP VALVE
From the fuel/oil heat exchanger HP metered fuel passes to the
pressurising and dump valve. Its function is to:
A. Prevent fuel flowing to the burners during the starting phase
until such time as fuel pressure is sufficient to give good
atomisation of the fuel thus ensuring good light-up.
B. Allow sufficient pressure to build up within the Fuel Control
Unit (FCU) servo/hydraulic control systems ensuring correct
metering of fuel supply is achieved during starting.
C. Enable a rapid dump of fuel remaining in the pipelines to the
burners on shutdown
PRESSURISING AND DUMP VALVE