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the unstaged fuel nozzles. This makes a stronger
flame pattern in the combustion chamber wich
helps to provide a better flameout margin at low
power.
• At higher power, the BSV opens and lets fuel
flow to the staged nozzles.
• BSV is remains open for these conditions:
• Engine at steady state on the ground
• ECU cannot read the BSV position
BSV
FFuueell Coonnttrrooll Syysstteem
32
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
16 standard fuel nozzles ( 8 staged / 8 unstaged )
4 wider spray pattern fuel nozzles placed adjacent to the igniters to help
engine operation during start and adverse weather conditions.
( 2 staged / 2 unstaged )
FUEL NOZZLES
FFuueell Coonnttrrooll Syysstteem
43
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
IDG Cooling System & FRV
HMU by-pass Fuel flow / Oil Cooler
FRV
The ECU controls
The fuel return flow to the aircraft through the FRV according to the oil T°
The Modulated Idle to create a higher fuel flow
( more dissipation of IDG oil T°)
IDG oil T°= Engine oil T°* 0.7
The FRV selects 3 levels of returning fuel flow
Zero Flow
Low Flow
High Flow
FFuueell Coonnttrrooll Syysstteem
44
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
• The IDG cooling logic performs two functions:
-The control of the FRV
-The control of the mini N2
• Both functions cool the IDG oil by cooling the fuel that goes into the IDG
oil/fuel heat exchanger.
• The FRV system returns hot fuel back to the aircraft fuel tanks.
This enables cooler fuel to be pumped to improve the IDG oil cooling.
• The mini N2 controls the temperature by increasing the idle speed of the
engine. The fuel T° because of the additional flow, due to the N2 increase.
FFuueell Coonnttrrooll Syysstteem
IDG Cooling System & FRV
45
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
GROUND oil T°> 90°c Low Return
until oil T°< 78°c
FLIGHT oil T°> 90°c Low Return
until oil T°< 78°c
oil T°> 95°c High Return
until oil T°< 85°c
then Low Return
Fuel Return Flow:
FFuueell Coonnttrrooll Syysstteem
IDG Cooling System & FRV
Low return = 300 Kg/h hot fuel + 200 Kg/h cold fuel
High return = 600 Kg/h hot fuel + 400 Kg/h cold fuel
46
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
GROUND No Modulated Idle
FLIGHT oil T°> 106°c N2% from 54 up to 77%
(oil T°from 106 up to 128°c)
IDG Modulated Idle:
FFuueell Coonnttrrooll Syysstteem
IDG Cooling System & FRV
47
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
78 90 EOT in deg C
78 85 90 95 EOT in deg C
1 st level
2 nd level
Modulated idle
FRV Operation:
Ground Flight
1 st level
FFuueell Coonnttrrooll Syysstteem
48
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
FRV will be closed:
• if N2 < 50% during engine start
• at engine shut down ( Master Lever Off )
• During take off and climb ( Fuel Flow reference )
• if wing tank level < 280 Kg
• if fuel over flow in surge tank
• if fuel feed is by gravity only
• if fuel T°> 52°c in the wing tank ( in flight )
FFuueell Coonnttrrooll Syysstteem
49
Flight Operations Support
10 September 2005
CFM PROPRIETARY INFORMATION
Subject to restrictions on the cover or first pa ge
VENT AIR
OIL TANK
SERVO FUEL
HEATER
20,5 liters
Supply Pump
FWD
Sump AGB AFT
Sump
Chip
Detectors
Scavenge
Pumps
Oil Filter
ANTI-SIPHON
DEVICE
MAX GULPING
EFFECT = 9.5 L
Back-up Filter
By-pass
Master Chip
Detector
MAIN FUEL / OIL
HEAT EXCHANGER
Oil FILTER CLOGGING
OIL P TRANSMITTER
LOW OIL PRESSURE SW
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CFFM556 Flight Operations Support(6)
