Engines Flashcards
The aircraft has two engines that supply power to the
aircraft.
4 types
- Pratt & Whitney’s PurePower PW1100G-JM
- CFM International LEAP-1A
- International Aero Engines V2500-A5
- CFM International CFM56-5B
The engines are turbofan engines that have:
7 items
‐ A high bypass ratio,
‐ A Full Authority Digital Engine Control (FADEC), ‐ A fuel system,
‐ An oil system,
‐ An air system,
‐ A thrust reverser system,
‐ An ignition system and a start system.
The engine has:
‐ Two compressor turbine assemblies: ___
‐ One accessory gearbox,
‐ One combustion chamber
- The Low Pressure (LP) compressor turbine assembly,
- The High Pressure (HP) compressor turbine assembly.
The engine operates as follows:
5 steps
- The LP compressor, compresses the air.
- Then, the air is divided into two flows:
‐ Most of the air flows out of the core engine, and provides most of the engine thrust.
‐ The remaining air enters the core engine. - The HP compressor compresses the air that enters the core engine.
- The fuel is added to and mixed with the compressed air of the core engine. The mixture is ignited
in the combustion chamber. - The gas that results from combustion drives the HP and the LP turbines.
ENGINES
The rotation speed of the fan provides the ___ engine parameter.
The rotation speed of the HP rotor provides the ___ engine parameter.
N1 / N2
The N1 and N2 engine parameters are ___ displayed in percentage.
current rotation speeds
The FADEC uses:
‐ The ___ engine parameter to compute the applicable engine thrust,
‐ The ___ engine parameters for engine control and monitoring.
N1 / N1 and N2
COMBUSTION CHAMBER
The combustion chamber burns a mixture of fuel and HP air. The FADEC controls the fuel/air mixture in accordance with the position of the
thrust lever and the aircraft operating conditions.
COMBUSTION CHAMBER
The combustion chamber is an annular assembly with fuel nozzles and two ___.
The combustion chamber is between ___.
igniters / the HP compressor and the HP turbine
The accessory gearbox drives various accessories with mechanical power via the ___ for the operation of the engine and the aircraft systems.
HP shaft
The accessory gearbox of each engine operates:
‐ The oil feed pump that provides the oil system with oil.
‐ The main engine fuel pump that provides the combustion chamber with fuel.
‐ The engine-driven hydraulic pumps that pressurize the GREEN and the YELLOW hydraulic
systems.
‐ The engine-driven generators that are the primary source of electrical power.
‐ The FADEC alternator that provides the FADEC with electrical power.
‐ The pneumatic starter that enables the engine start.
Each powerplant has a FADEC (Full Authority Digital Engine Control) system.
FADEC is a digital control system that performs complete engine management. FADEC has two-channel redundancy, with one channel active and one in standby. If one channel fails, the other automatically takes control.
The system has a magnetic alternator for an internal power source.
FADEC is mounted on the fan case.
The Engine Interface Unit (EIU) transmits to FADEC the data it uses for engine management.
The FADEC system performs the following functions :
- Control of gas generator
- Protection against engine exceeding limits
- Power management
- Automatic engine starting sequence
- Manual engine starting sequence
- Thrust reverser control
- Fuel recirculation control
- Transmission of engine parameters and engine monitoring information to cockpit
indicators - Detection, isolation, and recording of failures
- FADEC cooling
- Protection against engine stall
- Protection against Thrust Control Malfunction
The FADEC system performs the following functions :
PW vs. LEAP Engines
Protection against bowed rotor during engine start on ground
the FADEC can command an automatic dry cranking (engine cooling) to prevent any potential bowed rotor condition.
Note: A bowed rotor can occur when engine internal components cool at different rates, leading to unequal thermal expansion. This can cause some deflection (or bow) of the rotor shaft.
