DOC AIRBUS | AMM A320FENGINE FUEL AND CONTROL - GENERAL - DESCRIPTION AND OPERATION
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1. General
The fuel system enables delivery of a fuel flow corresponding to the power required and compatible with engine limits.
The system consist of :
** ON A/C NOT FOR ALL The fuel system enables delivery of a fuel flow corresponding to the power required and compatible with engine limits.
Fuel System - Block DiagramThe system consist of :
- the two stage fuel pump with low pressure and high pressure elements
- the hydromechanical unit, FADEC controlled
- the oil/fuel heat exchanger
- the servo fuel heater
- the IDG oil cooler
- the fuel filter
- the fuel return valve
- the fuel flow transmitter
- 20 dual cone fuel nozzles (16 standard and 4 pilot nozzles)
2. Component Location
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| ! FIN ! FUNCTIONAL DESIGNATION ! PANEL ! ZONE ! ACCESS ! ATA ! |
| ! ! ! ! ! DOOR ! REF. ! |
| !------!------------------------------------!-------!------!--------!---------! |
| 1KS1 EIU-1 87VU 127 824 73-25-34 |
| 1KS2 EIU-2 87VU 127 824 73-25-34 |
| 5KS1 ANN-ENG/1 FIRE FAULT 115VU 210 |
| 5KS2 ANN-ENG/2 FIRE FAULT 115VU 210 |
| 6KS SEL SW-ENG/MODE/CRANK/AUTO IGN/ 115VU 210 |
| IGN |
| 7KS1 P/BSW-ENG/FADEC GND PWR/1 50VU 212 |
| 7KS2 P/BSW-ENG/FADEC GND PWR/2 50VU 212 |
| 8KS1 CTL UNIT-THROTTLE, ENG 1 11VU 210 76-11-17 |
| 8KS2 CTL UNIT-THROTTLE, ENG 2 11VU 210 76-11-17 |
| 9KS1 P/BSW-ENG/MAN START/1 22VU 212 |
| 9KS2 P/BSW-ENG/MAN START/2 22VU 212 |
| 13KS1 SENSOR-TEMP, ENG 1 NACELLE 452 75-41-15 |
| 13KS2 SENSOR-TEMP, ENG 2 NACELLE 462 75-41-15 |
| 4000KS ECU 452 438 AR 73-21-60 |
| 438 BR |
| 462 438 AR |
| 438 BR |
| ------------------------------------------------------------------------------- |
3. Distribution
The fuel supplied from the tanks flows through a centrifugal pump, then through the oil/fuel heat exchanger and the HP fuel pump and filters.
The fuel from the HP fuel pump is delivered to the HMU in two flows :
The fuel flow goes then :
** ON A/C NOT FOR ALL The fuel supplied from the tanks flows through a centrifugal pump, then through the oil/fuel heat exchanger and the HP fuel pump and filters.
The fuel from the HP fuel pump is delivered to the HMU in two flows :
- the main flow is directly supplied to the HMU section which controls the fuel flow supplied to the fuel nozzles (through the fuel flowmeter).
- the other part of the fuel flow passes through the servo fuel heater.
- the active clearance control
- the compressor control (VBV, VSV).
The fuel flow goes then :
- One part back to the centrifugal pump outlet.
- One part back to the tank, mixed with cold fuel from the centrifugal pump outlet (only if the fuel return valve is open).
4. Controlling
A Full Authority Digital Engine Control (FADEC) controls the engine.
The FADEC achieves steady state and transient engine performances when operated with subsystems.
The FADEC is a dual channel ECU with cross talk and failure detection capability.
If a fault is detected, the FADEC will switch from one channel to the other.
If the two channels have an equal health status and N2 was more than 11000 RPM during last engine run, channels selection alternates with every engine shut-down.
The ECU channel selection is done on an alternating basis:
- When channel A is active at engine shutdown, channel B will become active at next ECU power-up.
- When channel B is active at engine shutdown, channel A will become active at next ECU power-up.
The channel that becomes active during engine start will remain active for the whole flight on condition that a fault does not occur in flight.
If a fault occurs, the ECU will select the channel with the better health status as the active channel.
A simplified hydromechanical unit includes a fuel metering valve and servo valves to control the compressor (VBV, VSV) and engine clearances.
The FADEC system performs the following functions:
** ON A/C NOT FOR ALL A Full Authority Digital Engine Control (FADEC) controls the engine.
The FADEC achieves steady state and transient engine performances when operated with subsystems.
The FADEC is a dual channel ECU with cross talk and failure detection capability.
If a fault is detected, the FADEC will switch from one channel to the other.
If the two channels have an equal health status and N2 was more than 11000 RPM during last engine run, channels selection alternates with every engine shut-down.
The ECU channel selection is done on an alternating basis:
- When channel A is active at engine shutdown, channel B will become active at next ECU power-up.
- When channel B is active at engine shutdown, channel A will become active at next ECU power-up.
The channel that becomes active during engine start will remain active for the whole flight on condition that a fault does not occur in flight.
If a fault occurs, the ECU will select the channel with the better health status as the active channel.
A simplified hydromechanical unit includes a fuel metering valve and servo valves to control the compressor (VBV, VSV) and engine clearances.
The FADEC system performs the following functions:
- the control of the fuel flow and engine air flow and bleeds (to automatically maintain forward, reverse thrust setting and provide satisfactory transient response)
- the engine limits protection
- the automatic starting capability
- the engine clearance control
- extensive diagnostic and maintenance capability
- thrust reverser operation.
5. Indicating
The engine fuel system is monitored from :
The warnings and cautions reflect :
The engine fuel system is monitored from :
- the ECAM display
- the warning and caution lights.
The warnings and cautions reflect :
- the engine health and status through the FADEC
- the FADEC health and status
- the fuel filter condition through a dedicated hardwire.