W DOC AIRBUS | AMM A320F

STORAGE AND DISTRIBUTION - DESCRIPTION AND OPERATION

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1. General
The oil storage and distribution system supplies filtered, temperature and pressure regulated oil to:
  • the engine,
  • the APU generator.
The system has:
  • an integral oil reservoir with a magnetic chip detector, an oil level sensor and an oil level sight glass,
  • an oil pressure pump,
  • two oil scavenge pumps,
  • two oil filters,
  • an oil cooler,
  • a de-oiling valve.
The APU has an integral lubrication system that lubricates and cools:
  • the power section,
  • the load compressor,
  • the accessory gearbox,
  • the generator.
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2. Component Location
F Oil System - Component Location ** ON A/C NOT FOR ALL
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FIN | FUNCTIONAL DESIGNATION | PANEL|ZONE|ACCESS | ATA
| | | | DOOR | REF.
-------------------------------------------------------------------------------
8073KM SWITCH and INDICATOR - DIFF.PRESS/ 315 315AL 49-91-21
GENERATOR SCAVANGE 316 316AR
8075KM INDICATOR - DIFF. PRESS/OIL PUMP 315 315AL 49-91-22
316 316AR
8078KM VALVE - PRESSURE RELIEF 315 315AL 49-91-43
316 316AR
8079KM OIL COOLER 315 315AL 49-91-44
316 316AR
8083KM VALVE - SOLENOID, DE-OILING 315 315AL 49-91-49
316 316AR
8084KM SENSOR - TEMPERATURE, HIGH OIL 315 315AL 49-91-51
316 316AR

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3. System Description
F Oil System - Component Location ** ON A/C NOT FOR ALL
F APU Oil System - Schematic ** ON A/C NOT FOR ALL
A. Storage
F Fill Ports, Sight Glass and Magnetic Drain Plug ** ON A/C NOT FOR ALL
(1) The lower part of the accessory drive gearbox (Ref. AMM D/O 49-26-00-00) is the integral oil reservoir of the APU. You can fill the oil reservoir by gravity fill. The gravity fill port is installed on the left side of the gearbox.
The scupper prevents that oil flows on to the APU and into the APU compartment during the gravity oil fill.
You can read the oil level on the oil sight glass. It must be between the FULL and the ADD mark.
The oil quantity of the gearbox sump at:
  • the FULL mark is 5.4 l (1.4265 USgal),
  • the ADD mark is 3.95 l (1.0435 USgal).
The difference between the two marks is 1.45 l (0.3830 USgal).
(2) When the oil level is too low, the low oil level sensor transmits a signal to the ECB 59KD (Ref. AMM D/O 49-93-00-00). With the APU not started and the aircraft on the ground the APU system page of the Electronic Instrument System (EIS) shows the LOW OIL LEVEL advisory message. Nothing is shown if the oil quantity is more than the set minimum.
(3) The oil reservoir has a connection to the ambient air through an air/oil separator. The air/oil separator is connected through a gearbox vent line to the APU exhaust cone.
(4) The oil drain plug is installed at the lowest point of the integral oil reservoir.
The electrical chip detector is installed in the drain plug. You can remove the drain plug with the chip detector installed. You can also remove the chip detector without the drain plug. The drain plug has a check valve which closes when you remove the chip detector. Thus it is not necessary to drain the oil reservoir for a visual check of the chip detector.
B. Distribution
(1) The subsequent components make the oil distribution system:
  • the oil pressure pump,
  • the oil scavenge pumps,
  • the pressure relief valve,
  • the de-oiling solenoid valve,
  • the oil cooler,
  • the oil filters,
  • the external and internal oil lines.
(2) Oil Pumps
The oil pumps are is installed on a pad on the accessory drive gearbox (Ref. 49-26-00). The oil pressure pump removes the oil from the oil reservoir by suction. It supplies the lubrication oil to the oil cooler and the pressure oil filter. The temperature regulated and filtered oil is supplied to the lubrication points of:
  • the APU front bearing,
  • the APU rear bearing,
  • the gearbox gears and its bearings,
  • the cooling fan,
  • the APU generator.
When the oil pump pressure gets to high, a pressure relief valve opens. This allows the oil to return to the oil sump.

The scavenged oil from the rear bearing and the generator falls into the sump and is returned to the oil reservoir with two oil scavenge pumps. The generator scavenge oil is filtered from the generator scavenge oil-filter before it enters the sump.
The oil which lubricates the gears and bearings of the gearbox, is returned to the reservoir by gravity.
(3) Oil Cooler
The oil cooler decreases the temperature of the oil. It is an oil/air heat exchanger which receives the cooling air from the cooling fan (Ref. AMM D/O 49-52-00-00). A serviceable oil cooler will keep the oil temperature within the limit during all operation conditions.
A bypass valve and a check valve regulate the internal pressure and the oil flow through the oil cooler. A bypass valve is installed between the oil cooler inlet and outlet and the check valve is installed at the oil outlet of the oil cooler.
(4) Filters
The distribution system has two oil filters:
  • the lubrication oil filter,
  • the generator scavenge oil-filter.
The filters remove unwanted materials from the oil. The pressure oil filter cleans all the lubrication oil before it is supplied to the lubrication points.
The generator scavenge oil-filter cleans unwanted materials from the generator scavenge oil. This makes sure that the generator does not give contamination to the oil in the oil reservoir.
Differential pressure indicators on the filter housings are latched out if the filter element is clogged. You can set the differential pressure indicator again manually.
The oil filters have a filter bypass valve which opens when the filter element is fully clogged. Then the oil does not flow through the filter element, but the APU receives lubrication oil.
The generator scavange oil-filter and the lubrication oil-filter have an electrical differential pressure switch whichalso transmits a signal to the ECB when the filter is blocked. The ECB stores the fault in its non-volatile memory.
(5) De-oiling Solenoid Valve
The de-oiling solenoid valve reduces the oil pressure pump load during the APU start, especially during the cold start condition when oil is very thick. The valve is located in the inlet of the oil pressure pump. A solenoid operates the valve position. The ECB controls the solenoid in relation to the APU speed.
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4. Interface
The Storage and distribution system has interface with:
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5. Component Description
A. Oil Pressure Pump
The main components of the pressure pump are:
  • the pump housing,
  • the pump rotor,
  • the vanes,
  • the pressure relief valve.
The oil pressure pump is a vane type unit consisting of a slotted inner rotor equiped with vanes, a precision ground cam profile and a housing body.
The main features of the pump are:
  • flow rate = 36 l.min (9.5101 USgal.mn)
  • pressure = 50 psi (3.4474 bar) to 60 psi (4.1369 bar).
    The spring loaded pressure relief valve opens when the pump pressure increases to more than 65 +-0 psi or -+10 psi (4.4816 ++0.0000 bar or -+0.6895 bar) Thus the oil returns to the oil sump.
B. Oil Filters
The main components of the oil filters are:
  • the filter housing,
  • the 20 micron disposable cartridge,
  • the differential pressure switch and indicator on the lubrication oil-filter,
  • the differential pressure switch and indicator on the generator scavenge oil-filter,
  • the filter bypass valve.
The two oil filters are installed in the APU oil system, one for high-pressure supply and one for the generator oil scavenge. The two filters have a differential pressure indicator button that pops out when the filter is clogged. When this occurs it is necessary to change the filter.
A differential pressure of 30 - 35 PSI between the inlet and the outlet of the filter causes the indicator button to pop out. Additionally, the scavenge filter and the lubrication filter have an electrical switch which gives signals to the ECB.
The filter bypass valve opens if the pressure in the filter increases to more than 50 +-0 psi or -+10 psi (3.4474 ++0.0000 bar or -+0.6895 bar).
C. Oil Cooler
The main components of the oil cooler are:
  • the oil cooler housing,
  • the check valve,
  • the bypass valve,
  • the drain plug.
The oil cooler is a tube type air-oil heat exchanger. The oil flows through tubes that are installed inside a housing. A cooling fan blows air across the tubes to an outlet. This removes the heat that has been transferred from the oil to the tubes.
The oil cooler bypass valve starts to open when the oil pressure in the oil cooler is more than 30 psi (2.0684 bar) and is fully open by 50 psi (3.4474 bar).
D. Generator Scavenge Pump
The main components of the generator scavenge pump are:
  • the pump housing,
  • the pump rotor,
  • the vanes.
The oil pressure pump is a vane type unit consisting of a slotted inner rotor equipped with vanes, a precision ground cam profile and a housing body.
The flow of the pump is 36 l.min (9.5101 USgal.mn).
E. Rear Bearing Scavenge Pump
The rear bearing scavenge pump is a gerotor positive displacement pump units consisting of two elements, an inner and an outer rotor.
The inner rotor has one less tooth than the outer, and has its centerline positioned at a fixed eccentricity from the centerline of the outer element. The inner element is driven by one pinion of the gearbox.
The flow of the pump is 2.6 l.min (0.6868 USgal.mn)
F. Magnetic Drain Plug
F Fill Ports, Sight Glass and Magnetic Drain Plug ** ON A/C NOT FOR ALL
The magnetic plug is a plug with a magnetic chip-detector that is immersed in the APU oil. This is installed into a check valve which prevents oil loss when the magnetic plug is removed for examination.
G. De-Oiling Solenoid Valve
The de-oil solenoid valve is installed above the oil level in the APU gearbox. This permits air to enter the inlet of the oil supply pump for cold start conditions. The air makes sure that the oil supply pump can not prime until 55% APU speed, which reduces pump drag. This drag slows the APU acceleration time due to the high viscosity of cold oil.
H. Oil Filler Ports
F Fill Ports, Sight Glass and Magnetic Drain Plug ** ON A/C NOT FOR ALL
The APU has a gravity fill port installed on the left side of the gearbox. You can put oil into the APU through fill port.
I. Sight Glass
F Fill Ports, Sight Glass and Magnetic Drain Plug ** ON A/C NOT FOR ALL
The sight glass is installed on the left side of the gearbox. It has a glass sheet that is sandwiched and sealed. The plate has a hole to permit vision of the oil through the glass. The ADD and FULL marks on the plate show when oil must be added.
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6. Operation/Control and Indicating
F APU Oil System - Schematic ** ON A/C NOT FOR ALL
The mechanically driven oil pressure pump removes the oil from the oil reservoir by suction. The oil passes to the oil cooler, then to the filter which retains any particles contained in the oil.
The ECB energizes the de-oiling solenoid valve during the APU start sequence. Thus opens the valve and air enters the oil pressure pump to reduce the load on this pump. Above 55% APU speed, the ECB de-energizes the solenoid and the de-oiling valve closes.
The oil lubricates and cools the following components:
  • the AC APU generator and its splines,
  • the cooling fan splines,
  • the gearbox gears and bearings,
  • the front bearing,
  • the rear bearing.
The gravity returns the scavenge oil from the APU generator, the splines, the gearbox gears and the front bearing to the oil reservoir. Two mechanically driven scavenge pumps removes the scavenge oil from the rear bearing and the generator sumps and returns it to the oil reservoir. The scavenge oil is filtered before it enters the reservoir.

If the pump pressure exceeds a given value, the pressure relief valve opens and returns the excess oil into the oil reservoir.
[Rev.10 from 2021] 2026.04.01 01:32:57 UTC
"Aviabrain" 2025