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CTC-201-214-01
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ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG

TRANSIENT BLEED VALVE
The TBV function is set during 2 modes:
-Starting.

- Transient. Through its internal logic, the ECU uses the output of the
transient and start bleed blocks to command the valve to
an open or closed position.
These blocks also command the HPTCC valve open,

during the start sequence.

The following engine parameters are taken into account: -N2 Accel. during transient conditions. -N2 Act. during starting conditions.

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CTC-201-217-02
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ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL
EFG
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EFG
HIGH PRESSURE TURBINE CLEARANCE CONTROL

EFFECTIVITY
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ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
CFM56-5B TRAINING MANUAL

EFG
HIGH PRESSURE TURBINE CLEARANCE CONTROL
The HPTCC system optimizes HPT efficiency through active clearance control between the turbine rotor and shroud and reduces compressor load during starting and transient engine conditions.
The HPTCC system uses bleed air from the 4th and 9th stages to cool down the HPT shroud support structure in order to:
-Maximize turbine efficiency during cruise.
-Minimize the peak EGT during throttle burst.
The HPTCC valve is located on the engine core section at the 3 o’clock position.
This is a closed loop system, using the valve position status as feedback.
The ECU uses various engine and aircraft sensor information to take into account the engine operating range and establish a schedule.
A thermocouple, located on the right hand side of the HPT shroud support structure, provides the ECU with temperature information.
To control the temperature of the shroud at the desired level, the ECU calculates a valve position schedule.
This valve position is then sent by the ECU active channel as torque motor current to the HPTCC servo valve, within the HMU.
The servo valve modulates the fuel pressure sent to command the HPTCC valve.
Two sensors (LVDT), connected to the actuator, provide the ECU with position feedback signals and the ECU changes the valve position until the feedback matches the schedule demand.

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CTC-201-223-01
EFFECTIVITY

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ALL CFM56-5B ENGINES FOR A319-A320-A321
ENGINE SYSTEMS Jan 03

CFMI PROPRIETARY INFORMATION
　
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