Ams Operation - Navistar International DT 466 Diagnostic/Troubleshooting Manual

294 7 ELECTRONIC CONTROL SYSTEMS DIAGNOSTICS
Figure 374 AMS components
1. EGR cooler
2. EGR tube assembly crossover
3. Intake and EGR mixer duct
(heater optional)

AMS Operation

Function
The Variable Geometry Turbocharger (VGT) has
actuated vanes in the turbine housing. The vanes
modify flow characteristics of exhaust gases through
the turbine housing. The benefit is the ability to
control boost pressure for various engine speeds and
load conditions.
The VGT is a closed loop system that uses the
Exhaust Back Pressure (EBP) sensor to provide
feedback to the Electronic Control Module (ECM).
The ECM uses the EBP sensor to continuously
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
4. EGR valve assembly
5. EBP sensor
6. Intake manifold
7. MAT sensor
monitor EBP and adjust the duty cycle to the VGT to
match engine requirements.
The VGT actuator is a control module that contains
a microchip and a DC motor.
is located below the turbocharger.
operates a DC motor which rotates a crank lever
controlling the vane position in the turbine housing.
The position of the vanes is based off the pulse width
modulated signal sent from the ECM.
Actuated vanes are mounted around the inside
circumference of the turbine housing. A unison ring
links all the vanes. When the unison ring moves,
all vanes move to the same position. Unison ring
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
8. MAP sensor
9. Cylinder head
10. Turbocharger (VGT)
11. Exhaust manifold
The VGT actuator
The microchip