SsangYong Korando III (2010 year). Manual - part 50
06-21
0000-00
Basic principle at low speed
At low speed, it utilizes the principle of venturi. For
example, when air flows through the venturi tube,
the flow speed is faster and the pressure is lower
at the point "A". In this case, if the inner diameter
of venturi is more narrowed, the flow speed is so
much faster (refer to the equation).
※
Control
range
Turbocharger driving
mechanism
Control method
Effect
Improved
performance
At low
speed
Narrows the flow
passage for the
exhaust gas by
folding the vanes
The flow rate is
increased as the
exhaust gas passes
the narrow passage
→ Increased
turbine & impeller
speed, Increased
compressive force
Improved
low speed torque
4. OPERATING PRINCIPLES
The E-VGT is designed to get more improved engine power in all ranges by controlling the turbine as
follows:
1) How it Works at Low Speed
Normal turbocharger cannot get the turbo effect because the amount of exhaust gas is not enough and
the flow speed is slow in a low speed zone, but VGT allows the flow passage of exhaust to narrow,
resulting in increasing the flow speed of exhaust gas and running the turbine quickly and powerfully.
Therefore, as VGT can intake more air than normal turbocharger, it can give the benefit of the increased
output even in a low speed zone.
Turbocharger lag
The turbocharger is at idle speed when there is no load or it is in the normal driving condition. During
this period, the amount of exhaust gas passing through the turbine is not enough to turn the
compressor wheel (impeller) fast. Therefore, the intake air is not compressed as needed.
Because of this, it takes time for turbocharger to supply the additional power after the accelerator
pedal is depressed. This is called "turbocharger lag".