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TGB
OIL T°
OIL QUANTITY
SUPPLY CIRCUIT lubricates Bearings & Gears
SCAVENGE CIRCUIT: Oil back from engine to tank.
VENT CIRCUIT balances internal air pressure
Oiill Syysstteem CFFM5566--55B
50
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
Compressor
Airflow
Control
VSV
VBV
Engine
Clearance
Control
TBV
HPTCC
LPTCC
Aiirr Coonnttrrooll Syysstteem
51
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
VBV: Variable Bleed Valve
• The VBV system controls the LPC
discharge airflow.
• The VBV system bleeds the LPC
air out into the secondary airflow to
prevent stalls, reduce water and
foreign object damage ingestion into
the HPC.
• The ECU uses the HMU to control
the VBV system.
• The HMU sends servo fuel
pressure to move the VBV actuator.
• The actuator sends an electrical
position feedback signal to the ECU.
Aiirr Coonnttrrooll Syysstteem
52
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
Descent & APP Transitory
T/Off
&
Cruise
Variable Bleed Valve
Aiirr Coonnttrrooll Syysstteem
53
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
Maxi
Efficiency
Design
Point
ISO N1 Line
Efficiency
¯¯
BOOSTER OUTLET AIRFLOW
B
OOST
E
R
P
RESS
URE
RATI
O
LOW EFFICIENCY
1 REGION
5
3
4
VBV
Operation
1 Acceleration Schedule
5
3
4
• Low speed
or Deceleration

VBV OPEN
• High speed
or acceleration

VBV CLOSED
Typical LPC flow chart
2
2
Operating Line
Deceleration Schedule
If VBV not open
If VBV not closed
STALL
REGION
IDLE
MCT
Variable Bleed Valve
Aiirr Coonnttrrooll Syysstteem
54
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
IGV
ROTOR
VSV 1
Etc
…
IGV (Inlet Guide Vane)
ROTOR
STAGE
VSV (3)
• The VSV system controls
the HPC inlet airflow.
• The VSV system gives the
correct quantity of air to the
HPC.
• The ECU uses the HMU to
control VSV system.
• The HMU sends servo fuel
pressure to move 2 VSV
actuators.
• The 2 actuators move the
variable stator vanes.
• Each actuator sends an
electrical position feedback
signal to the ECU.
VSV: Variable Stator Vanes
Aiirr Coonnttrrooll Syysstteem
- VSV optimise HPC efficiency.
- VSV improve stall margin
for transient engine operations.
55
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
Low Z < 17500 ft
High Z > 25000 ft
If between, the previous selected
position is confirmed
Transient if:
App idle is selected or, either FMV or VSV parameter is invalid or, N2 Accel
or Decel rate changed or, actual N2 < N2min + 100 rpm with N2 < 10875 rpm
Steady Transient
VSV: Variable Stator Vanes
Aiirr Coonnttrrooll Syysstteem
56
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
COMPRESSOR OUTLET AIRFLOW
C
O
MP
R
ES
S
OR
P
R
ES
S
UR
E
R
AT
I
O
LOW EFFICIENCY
REGION
STALL
REGION
Efficiency
¯¯
Maxi
Efficiency
Design
Point
ISO N1 Line
VSV
Operation
1
4
2
• Low speed
or deceleration

VSV CLOSED
• High speed
or acceleration

VSV OPEN
3
IDLE
MCT
1 Acceleration Schedule
3
4
2
Deceleration Schedule
Operating Line
If VSV not open
Typical HPC flow chart
Variable Stator Vanes
Aiirr Coonnttrrooll Syysstteem
57
Flight Operations Support
　
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本文鏈接地址：CFFM556 Flight Operations Support(7)