DOC AIRBUS | AMM A320FOIL - GENERAL - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. The purpose of the oil system is to provide oil lubrication to the engine main bearings and to the Accessory Gearbox (AGB) bearings and gears, Transfer Gearbox (TGB) bearings and gears,and Inlet Gearbox (IGB) bearings and gears, the oil storage includes the oil tank. There are three different subsystems.
(1) The storage which keeps a sufficient quantity of oil to continuously supply the oil distribution circuit (Ref. AMM D/O 79-10-00-00).
(2) The distribution is composed of three different circuits (Ref. AMM D/O 79-20-00-00):
- A supply circuit to provide oil lubrication to engine, AGB, TGB and IGB bearings and gears
- A scavenge circuit which recovers, filters and flows the oil back to the storage circuit (oil tank).
- A vent circuit to balance the internal air pressures in the oil system.
(3) The indicating which provides oil system monitoring to the cockpit through the oil pressure, oil temperature, oil quantity and oil contamination.
2. System Description
A. Supply Circuit
At engine start-up, the supply pump draws the oil from the oil tank through the anti-leak valve and pressurizes it. In case of overpressure, a relief valve bypasses the excess of oil flow to the suction side of the a sump scavenge pump (Ref. AMM D/O 79-10-00-00).
Downstream of the supply filter, the oil flows through the outlet port to the non return valve which prevents the heat exchangers drainage and siphoning in the AGB when the engine is shutdown. Then, the oil flows through the servo fuel heater, the engine surface air cooling oil cooler and the main heat exchanger where oil cooling with fuel or air is achieved through conduction and convection. The three cooling components also have bypass valves in case of matrix clogging (Ref. AMM D/O 73-10-00-00).
Then the oil is delivered through three lines to the bearings of the AGB and TGB, the A sump, and the B and C sumps. Dedicated circuit feeds engine oil dampers with oil at higher pressure than bearing supply circuit through the oil pressurizing valve of the main heat exchanger.
The five scavenge pumps scavenge the air/oil mix present in the three sumps and gearboxes after lubrication. The air/oil mixtures flows through five strainers, located on each scavenge line before entering the lubrication unit to protect each scavenge pump from contamination. The sump scavenge pump also receives the flow internally bypassed from the supply pump through the pressure relief valve. The flow from the five scavenge pumps are mixed together at the scavenge common outlet.
The scavenged air/oil mix flows out from the lubrication unit to the air/oil separator where air is separated from oil that returns to the oil tank while excessive air is vented to the AGB. The air/oil separator is part of the oil debris monitoring system which captures the debris and provides an electrical signal to the ECU for indication (Ref. AMM D/O 79-30-00-00).
At engine start-up, the supply pump draws the oil from the oil tank through the anti-leak valve and pressurizes it. In case of overpressure, a relief valve bypasses the excess of oil flow to the suction side of the a sump scavenge pump (Ref. AMM D/O 79-10-00-00).
Downstream of the supply filter, the oil flows through the outlet port to the non return valve which prevents the heat exchangers drainage and siphoning in the AGB when the engine is shutdown. Then, the oil flows through the servo fuel heater, the engine surface air cooling oil cooler and the main heat exchanger where oil cooling with fuel or air is achieved through conduction and convection. The three cooling components also have bypass valves in case of matrix clogging (Ref. AMM D/O 73-10-00-00).
Then the oil is delivered through three lines to the bearings of the AGB and TGB, the A sump, and the B and C sumps. Dedicated circuit feeds engine oil dampers with oil at higher pressure than bearing supply circuit through the oil pressurizing valve of the main heat exchanger.
The five scavenge pumps scavenge the air/oil mix present in the three sumps and gearboxes after lubrication. The air/oil mixtures flows through five strainers, located on each scavenge line before entering the lubrication unit to protect each scavenge pump from contamination. The sump scavenge pump also receives the flow internally bypassed from the supply pump through the pressure relief valve. The flow from the five scavenge pumps are mixed together at the scavenge common outlet.
The scavenged air/oil mix flows out from the lubrication unit to the air/oil separator where air is separated from oil that returns to the oil tank while excessive air is vented to the AGB. The air/oil separator is part of the oil debris monitoring system which captures the debris and provides an electrical signal to the ECU for indication (Ref. AMM D/O 79-30-00-00).
B. Vent Circuit
A vent line connects the oil tank with the AGB. Internally, the AGB and TGB also connect with the fwd sump. The three sumps vent out through the center vent tube.
A vent line connects the oil tank with the AGB. Internally, the AGB and TGB also connect with the fwd sump. The three sumps vent out through the center vent tube.