SSANGYONG KORANDO 2013 Service Manual

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1. SYSTEM DESCRIPTION OF E-VGT
(Electric-Variable Geometry Turbine)
A turbocharger is a centrifugal compressor powered by a high speed turbine that is driven by an engine's
exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine (forced
induction), thereby resulting in greater performance (for either, or both, power and efficiency). As the
turbine, at exhaust end, is rotated by exhaust gas pressure the impeller, at intake end, gets rotated to
send air around center of the impeller, being circumferentially accelerated by the centrifugal force, into
the diffuser. The air, which has been introduced to the diffuser having a passage with big surface,
transforms its speed energy into the pressure energy while being supplied to the cylinder improving the
volume efficiency. Also, the exhaust efficiency improves as the exhaust turbine rotates. The
turbocharger is often referred to as the exhaust turbine turbocharger.
The E-VGT system installed to the D20DTF engine variably controls the passages of the turbine
housing to regulate the flow rate of the exhaust gas. The actuator of E-VGT is a DC motor actuator (E-
Actuator) which controls more quickly and precisely than the previous vacuum type actuator.
The engine ECU controls the E-Actuator electronically as follows:
Diffuser: With the meaning of spreading out it is a device that transforms fluid's speed energy into the
pressure energy by enlarging the fluid's passage to slow down the flow.
At low speed: Narrows the flow passage for the exhaust gas, resulting in increasing the flow speed
of the exhaust gas and running the turbine quickly and powerfully.
At high speed: Expands the flow passage for the exhaust gas, resulting in increasing the mass flow
of the exhaust gas and running the turbine more powerfully. -
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Maximizes the intake air charging efficiency (Approx. 15%) -Optimizes the exhaust gas flow rate by controlling the vanes inside the turbine housing with the E-
Actuator. 1.
(2) E-Actuator (Electric-Actuator, Rotary type)
Target temperature and airflow control -Enhanced emission control: By temperature control with CDPF system 1.
(1) Performance (for EURO V)
Has a faster response time than the conventional vacuum actuator 2.
Improved low speed torque, high speed power and fuel economy.
Improved acceleration performance with rapid response time of vane -
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1) Features
Features
BenefitsFolding and unfolding of the vane
is controlled electrically
Easy to get low speed air volume
Rapid response time
Electric control -
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Improved low speed torque
Improved low speed torque and
power
Reduced exhaust gas
Improved fuel consumption
Improved acceleration
performance -
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E-VGT turbocharger
Improves engine power
T-MAP sensor
Boost pressure and
temperature
2. COMPONENTS
Engine ECU (D20DTF)
E-VGT duty controlAccelerator pedal position
sensor
Transfers accelerating demand
to ECU
Atmospheric pressure, RPM
signal
HFM sensor
Improves the engine powerCoolant temperature sensor
Operates the VGT according to
engine warm-up
For more information about control logic, refer to Chapter "Engine Control".

3. INPUT/OUTPUT DEVICES

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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
rangeTurbocharger driving
mechanismControl method
EffectImproved
performance
At low
speedNarrows the flow
passage for the
exhaust gas by
folding the vanesThe flow rate is
increased as the
exhaust gas passes
the narrow passage
turbine & impeller
speed, Increased
compressive forceImproved
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".

2) How it Works at High Speed
In a high speed zone, the amount of exhaust gas increases and it is accompanied with a great force.
Therefore, if the inner diameter of venturi is more widened, the turbine in the turbocharger by the
releasing force of abundant exhaust gas can deliver a more increased energy to the compressor. The
output will increase in submission to the increase of intake air volume.
Control
rangeTurbocharger driving
mechanismControl method
EffectImproved
performance
At high
speedExpands the flow
passage for the
exhaust gas by
unfolding the vanesThe flow rate is
increased due to the
Increased turbine &
impeller speed,
Increased
compressive forceImproved
maximum
power