DOC AIRBUS | AMM A320FENGINE FUEL AND CONTROL - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The APU-side fuel system meters and distributes the fuel it receives from the A/C APU fuel supply system (Ref. AMM D/O 28-22-00-00).
Incoming fuel is received by the fuel control unit (FCU) and pumped to the flow divider. From there it is ducted via the fuel manifolds to the fuel nozzles.
A separate fuel circuit is provided to hydraulically operate the IGV-actuator and the BCV-actuator.
** ON A/C NOT FOR ALL The APU-side fuel system meters and distributes the fuel it receives from the A/C APU fuel supply system (Ref. AMM D/O 28-22-00-00).
Incoming fuel is received by the fuel control unit (FCU) and pumped to the flow divider. From there it is ducted via the fuel manifolds to the fuel nozzles.
A separate fuel circuit is provided to hydraulically operate the IGV-actuator and the BCV-actuator.
2. Component Location
** ON A/C NOT FOR ALL 
APU Fuel System - Component Location| ------------------------------------------------------------------------------- |
| FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA |
| | | | | DOOR | REF. |
| ------------------------------------------------------------------------------- |
| 8022KM FUEL CONTROL UNIT (FCU) 315 315AL 49-32-11 |
| 8024KM FLOW DIVIDER 315 315AL 49-32-12 |
| 8020KM MANIFOLD - MAIN FUEL 315/ 315AL/ 49-31-41 |
| 316 316AR |
| 8021KM MANIFOLD - PILOT FUEL 315/ 315AL/ 49-31-42 |
| 316 316AR |
3. System Description
A. Fuel Distribution (Ref. 49-31-00)
Incoming fuel from the A/C APU fuel supply system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the BCV-actuator. Returned fuel from the actuators is routed back into the FCU fuel inlet.
The FCU also pressurizes and meters the fuel destined for APU operation. The fuel is ducted via a supply line to the flow divider, which distributes the fuel, depending on APU operating conditions, to the pilot and/or main fuel manifold. These deliver the fuel to the 3 pilot fuel injectors and/or the 6 main fuel injectors, located around the circumference of the combustion chamber. There the fuel is atomized.
Incoming fuel from the A/C APU fuel supply system is received by the FCU. The FCU diverts some of the fuel into a hydraulic circuit to operate the IGV-actuator and the BCV-actuator. Returned fuel from the actuators is routed back into the FCU fuel inlet.
The FCU also pressurizes and meters the fuel destined for APU operation. The fuel is ducted via a supply line to the flow divider, which distributes the fuel, depending on APU operating conditions, to the pilot and/or main fuel manifold. These deliver the fuel to the 3 pilot fuel injectors and/or the 6 main fuel injectors, located around the circumference of the combustion chamber. There the fuel is atomized.
B. Fuel Control (Ref. 49-32-00)
The APU fuel control subsystem operates fully automatically. During APU operation, the FCU, which is governed by the ECB, meters the fuel dependent on the APU load condition. The flow divider distributes the fuel via both fuel manifolds to the fuel nozzles. During APU start-up/shut-down, the FCU increases/reduces the quantity of fuel delivered to the flow divider accordingly. During APU start, the flow divider routs fuel to the combustion chamber via the pilot fuel manifold only.
The APU fuel control subsystem operates fully automatically. During APU operation, the FCU, which is governed by the ECB, meters the fuel dependent on the APU load condition. The flow divider distributes the fuel via both fuel manifolds to the fuel nozzles. During APU start-up/shut-down, the FCU increases/reduces the quantity of fuel delivered to the flow divider accordingly. During APU start, the flow divider routs fuel to the combustion chamber via the pilot fuel manifold only.