DOC AIRBUS | AMM A320FOIL PRESSURE SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 4019KS | BYPASS VALVE-ENGINE FUEL/OIL HEAT EXCHANGER | 400 | 79-21-51 | ||
| 4049EM | CHECK VALVE-LUBE TRIM | 400 | 73-11-42 | ||
| 4069KS | VARIABLE OIL FLOW REDUCTION VALVE | 400 | 73-11-42 | ||
| 4076KS | ACTIVE OIL DAMPER VALVE | 400 | 73-11-42 | ||
| 6002EM | HEAT EXCHANGER-AIR/OIL | 400 | 79-21-42 | ||
| 6003EM | HEAT EXCHANGER-FUEL/OIL, ENGINE | 400 | 79-21-43 | ||
| 6004EM | PUMP-OIL, LUBRICATION AND SCAVENGE | 400 | 72-20-00 | ||
| 6005EM | FILTER ELEMENT-OIL | 400 | 79-21-44 | ||
2. System Description
Oil Pressure SystemA. Fuel/Oil Heat Exchanger Bypass Valve
(1) The engine fuel/oil heat exchanger bypass valve is located on the fuel/oil manifold at approximately the 10 o'clock position.
(a) The fuel/oil heat exchanger bypass valve is an electromechanical device that variably splits the supply flow from the fuel/oil heat exchanger to the air/oil heat exchanger to control the temperature of the oil and fuel.
(b) The valve is located on the Oil Control Module (OCM).
(c) The fail-safe position is 92.5 percent flow to the fuel/oil heat exchanger and 7.5 percent to the air/oil heat exchanger.
(d) The valve is fully modulated with no position feedback necessary to the Electronic Engine Control (EEC), which commands the valve. The fuel/oil heat exchanger bypass valve is a line replaceable unit.
B. Oil Control Module (OCM)
(1) The lube trim check valve is located in the OCM at approximately the 9 o'clock position.
(a) The OCM gets pressurized, filtered oil from the lubrication and scavenge oil pump and distributes the oil to different engine compartments and heat exchangers through internal cored passages.
(b) The OCM greatly reduces the number of external oil lines necessary to supply pressurized oil.
(c) The OCM is located adjacent to the Main Gearbox (MGB).
C. Variable Oil Reduction Valve (VORV)
(1) The VORV is attached to the OCM on the left of the engine at approximately the 9 o'clock position.
(a) The VORV is an electromechanical device that regulates the flow of oil to the No. 1, No. 1.5, No. 2 and FDG for different flight conditions.
1 Full oil flow to lubricate the gear faces is only necessary at high engine power conditions. At cruise, a small quantity of direct oil flow is necessary and oil bypasses the loads to decrease the oil heat load and increase gearbox efficiency.
a Valve position is directly related to N2 speed and oil pressure.
2 The valve is fully modulated by a servo valve controlled by the EEC on channels A and B. Feedback is given by a Linear Variable Differential Transducer (LVDT).
3 The fail-safe valve position is maximum oil flow.
(b) The VORV includes a second valve contained in the same housing called the Journal Oil Shuttle Valve (JOSV).
(c) The VORV is a line replaceable unit.
D. Journal Oil Shuttle Valve (JOSV)
(1) The JOSV is a mechanical device that continuously supplies oil to the fan drive journal bearings from the main oil supply or the auxiliary oil supply.
(2) The JOSV operates independently of the VORV but is located in the same housing.
(3) In normal conditions, the JOSV sends oil from the main oil pump to the journal bearings and scavenge oil from the No. 1 and No. 1.5 bearing support to the OCM. In windmill and zero or negative gravity (G) conditions, scavenge oil from the No. 1 and No. 1.5 bearing support is sent back to the journal bearings.
(4) The JOSV is not controlled by the EEC and gives no feedback. Valve position changes with oil pressure.
E. Active Oil Damper Valve (AODV)
(1) The AODV is attached to the OCM at approximately the 9 o'clock position.
(a) The AODV controls oil supply flow to the No. 3 bearing oil damper for high rotor (N2) vibration control.
(b) The AODV is located on the OCM.
(c) The valve is made to let oil flow to the damper at engine ignition and shuts the oil supply off at high power.
(d) The fail-safe position for the valve is open.
(e) The AODV is a line replaceable unit.
F. Engine Air/Oil Heat Exchanger
(1) The air/oil heat exchanger is located on the diffuser case at approximately the 10 o'clock position.
(a) The engine air/oil heat exchanger cools the engine oil with fan bypass air.
(b) The engine oil that is cooled by the air/oil heat exchanger decreases the quantity of heat that must be moved from the oil to the fuel in the fuel/oil heat exchanger.
(c) The engine air/oil heat exchanger is located at flange H on the diffuser case at the 11 o'clock position.
(d) The engine air/oil heat exchanger, which receives pressurized oil from the fuel/oil heat exchanger bypass valve, has plates through which the engine oil flows. There are fins brazed onto the plates with passages.
(e) The fins are used to move heat from the plate walls to the fan bleed air that flows between the plates. The heated air then flows to the nacelle area. An open bypass valve lets the oil bypass the air/oil heat exchanger when the oil is cold or the heat exchanger core is clogged.
(f) The EEC controls the flow of engine oil to the air/oil heat exchanger by commanded input to the fuel/oil heat exchanger bypass valve.
1 It increases the oil flow if the fuel temperature is more than a specified value. The increased oil flow decreases the oil flow through the fuel/oil heat exchanger which decreases the quantity of heat transfer to the fuel in the fuel/oil heat exchanger.
G. Integrated Drive Generator (IDG) Oil/Oil Heat Exchanger
(1) The Integrated Drive Generator (IDG) oil/oil heat exchanger is attached to the Thermal Management System (TMS) manifold at approximately the 8 o'clock position.
(a) The IDG oil/oil heat exchanger moves heat from the IDG oil to the engine oil from the engine air/oil heat exchanger outlet.
(b) The IDG oil/oil heat exchanger is connected to the Thermal Management System (TMS) manifold.
(c) The heat exchanger, which receives cooled, pressurized oil from the engine air/oil heat exchanger, has plates through which the IDG oil flows. There are fins attached to the plates.
(d) The fins move heat from the plate walls to the engine oil that flows between the plates. The engine oil at increased temperature then flows downstream to mix with engine oil discharged from the engine fuel/oil heat exchanger.
(e) A bypass valve lets the oil bypass the heat exchanger when the oil is cold or the heat exchanger is clogged.
(f) The IDG oil/oil heat exchanger is a line replaceable unit.
H. Fuel/Oil Heat Exchanger
(1) The engine fuel/oil heat exchanger is located on the TMS at approximately the 8 o'clock position.
(a) The fuel/oil heat exchanger moves heat from the engine oil to the engine fuel.
(b) The fuel/oil heat exchanger is attached to the High Pressure Turbine (HPT) case at the 9 o'clock position.
(c) The heat exchanger has stacked fuel and oil plates which let the heat transfer.
(d) The heated fuel is sent to the fuel temperature sensor.
(e) The cooled engine oil that flows through the TMS manifold lubricates and decreases the temperature of the engine bearings, gears and accessory drives.
(f) An oil bypass valve causes oil to bypass the fuel/oil heat exchanger if there is a clog.
I. Main Oil Filter Element
(1) The oil filter element is located on the lubrication and scavenge oil pump at approximately the 8 o'clock position.
(a) The main oil filter element removes solid contaminants from the pressurized oil sent from the lubrication and scavenge oil pump.
(b) The filtered oil goes from the main oil filter to the Oil Control Module (OCM).
(c) The main oil filter element is in the main oil filter housing attached to the lubrication and scavenge oil pump.
(d) The main oil filter housing contains:
- A dual element (primary and secondary) oil filter assembly
- A primary oil filter bypass valve
- A check valve (shut-off valve) to prevent oil leakage during filter service
- A mechanically activated static anti-leak valve to prevent back-flow during shutdown.
(e) In normal operation, the oil flows from the lubrication and scavenge oil pump and into the outer part of the filter to the inner part through the primary and secondary filter elements.
(f) The element is also a dual element design. The dual element oil filter is a filter in a filter design, with a primary filter bypass valve installed in the filter assembly. Because the filter function is redundant (primary and secondary filters) the filter function cannot fail.
(g) The dual element design has a coarse filtration secondary element in the finer filtration primary element that will continue to supply a level of protection to the engine.
(h) The oil filter differential pressure sensor gives an indication if the primary oil filter has clogged.
1 The differential pressure sensor is installed on the lubrication and scavenge oil pump, adjacent to the oil filter housing.
2 Two pressure connections, one upstream and one downstream of the main oil filter element, supply the pressures used to monitor differential oil pressure.
3 The main oil differential pressure sensor is connected to the two pressure connections.
4 When the differential pressure across the filter is more than a specified limit, a maintenance flag is set.
5 When the differential pressure across the primary oil filter element is more than a specified limit, pressurized oil is sent directly to the secondary filter.
6 An oil filter bypass signal is also sent to the flight crew through the EEC.
J. Last Chance Oil Strainers
(1) Last chance oil strainers are used to keep large particles from the bearing compartments and prevent blockage of the oil nozzles.
(a) The strainers keep contamination away from the oil nozzles that gets into the system downstream of the main oil filter.
(2) The metal mesh last chance oil strainers are externally mounted on the engine.
(a) The FDG and No. 1, 1.5 and 2 bearing oil strainer is installed at the VORV manifold outlet.
(b) The two No. 3 bearing and bevel gear oil strainers are located in the oil pressure tubes that go to the No. 3 bearing compartment on the Compressor Intermediate Case (CIC).
(c) The No. 4 bearing oil strainer is in the lubrication pressure tube that goes to the No. 4 bearing compartment.
(d) The No. 5 and 6 bearing oil strainer is located in the lubrication pressure tube that goes to the No. 5 and 6 bearing compartment.
(e) The gearbox oil strainer is located in the OCM housing.
(3) Last chance oil strainers are line replaceable units.