SsangYong Actyon Sports II. Manual — part 34

06-19

1914-01

T-MAP sensor

Booster pressure and
temperature

E-VGT turbocharger

Improves engine power

2. COMPONENTS

Engine ECU (D20DTR)

E-VGT duty control

Accelerator pedal position

sensor

Transfers driver's will to
accelerate to ECU

Atmospheric pressure, RPM

signal

HFM sensor

Improves the engine power

Coolant temperature sensor

Operates the VGT according to
engine warm-up

For details about control logic, refer to Chapter “Engine Control”.

*

06-20

3. INPUT/OUTPUT DEVICES

06-21

1914-01

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".

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).

※

06-22

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

range

Turbocharger driving

mechanism

Control

method

Effect

Improved

performance

At high
speed

Expands the
flow passage for
the exhaust gas
by unfolding the
vanes

The flow rate is
increased due to the
expanded
passage→
Increased turbine &
impeller speed,
Increased
compressive force

Improved
maximum
power