Iveco Stralis AT/AD. Manual - part 29
Compressed air (hot)
Intake air
Engine exhaust gas
Compressed air (cooled)
Figure 206
The turbocharging system consists of:
- air filter;
- variable geometry turbocharger;
- “intercooler” radiator.
44916
TURBOCHARGING DIAGRAM
TURBOCHARGER
Operating principle
The variable geometry turbocharger (VGT) consists of a
centrifugal compressor and a turbine, equipped with a
mobile device which adjusts the speed by changing the area
of the passing section of exhaust gases to the turbine.
Thanks to this solution, gas velocity and turbine speed can
be high even when the engine is idling.
If the gas is made to go through a narrow passage, in fact,
it flows faster, so that the turbine rotates more quickly.
The movement of the device, choking the exhaust gas
flowing section, is carried out by a mechanism, activated by
a pneumatic actuator.
This actuator is directly controlled by the electronic control
unit by a proportional solenoid valve.
The device is in maximum closing condition at idle speed.
At high engine operating speed, the electronic control
system is activated and increases the passing section, in
order to allow the in-coming gases to flow without
increasing their speed.
A toroidal chamber is obtained during the casting process
in the central body for the passage of the coolant.
102
ENGINE F2B
S
TRALIS
AT/AD
Base - January 2003
TURBOCHARGING