Variable Nozzle Turbocharger - Detroit Diesel Series 60 EGR Technician Manual

DDEC IV COMPONENTS

Variable Nozzle Turbocharger

Variable nozzle turbocharger (VNT), see Figure 2-9, uses a high pressure pneumatic actuator to
regulate and control turbine vanes. There is no wastegate with this system. The VNT actuator is
mounted on a bracket attached to the turbocharger and receives air pressure from engine-mounted
VPODs. VNT actuator connects via a rod to the pin joint of the turbine external arm. Rotation
of external arm simultaneously rotates several pivoting nozzle vanes positioned inside turbine
housing at the outer periphery of turbine wheel. This adjusts turbocharger speed, boost and EGR
flow in accordance with DDEC engine management control.
NOTE:
VNT actuator is spring loaded. If air pressure is lost the actuator will open the VNT
vanes resulting in low/no boost.
Figure 2-9 Variable Nozzle Turbocharger
2-10
All information subject to change without notice. (Rev. June 2005)
7SE60 0506 Copyright © 2005 DETROIT DIESEL CORPORATION