2013 SSANGYONG NEW ACTYON SPORTS Service Manual

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(8) Swirl control
A. Overview
Variable swirl valve ▶
The strong swirl caused by intake air is important element for anti-locking function in diesel engine. The
swirl control valve partially closes the intake port to generate the swirl according to the engine conditions.
When the engine load is in low or medium range, the swirl could not be generated because the air flow is
slow. To generate strong swirl, there are two passages in intake manifold, and one of them has the valve
to open and close the passage. When the valve closes the passage, the air flow through the another
passage will be faster, and the strong swirl will be generated by the internal structure of the passage. This
swirl makes the better mixture of air and fuel, eventually the combustion efficiency in combustion
chamber could be improved. This provides the enhanced fuel consumption, power and EGR ratio.
Components ▶
HFMCrankshaft position sensorVariable swirl valve
Coolant temperature
sensorAccekerator pedal
moduleD20DTR ECU

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B. Input/Output for variable swirl valve

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C. Types of swirl
Swirl: One cylinder has two intake air ports, one is set horizontally and
the other one is set vertically. Swirl is the horizontal air flows in cylinder
due to the horizontal intake air ports.
Tumble: Tumble is the vertical air flows in cylinder due to the vertical
intake air port
Tumble: Tumble is the vertical air flows in cylinder due to the vertical
intake air port
D. Swirl control
In DI type diesel engine, the liquefied fuel is injected into the cylinder directly. If the fuel is evenly
distributed in short period, the combustion efficiency could be improved. To get this, there should be
good air flow in cylinder. In general, there are two intake ports, swirl port and tangential port, in each
cylinder. The swirl port generates the horizontal flow and the tangential port generates the longitudinal
flow. In low/mid load range, the tabgential port is closed to increase the horizontal flow. Fast flow
decreases the PM during combustion and increases the EGR ratio by better combustion efficiency.

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LoadEngine speed Swirl valveAmount of
swirlRemarks
Low speed,
Low loadbelow 3,000 rpm
Closed HeavyIncreased EGR ratio, better air-fuel
mixture (reduce exhaust gas)
High speed,
High loadover 3,000 rpm
Open LightIncrease charge efficiency, higher
engine power
The variable swirl valve actuator operates when
turning the ignition switch ON/OFF position to
open/close the swirl valve. In this period, the soot
will be removed and the learning for swirl valve
position is performed.
Swirl: This is the twisted (radial) air flow along the cylinder wall during the intake stroke. This
stabilizes the combustion even in lean air-fuel mixture condition.
Swirl valve
E. Features
Swirl and air intake efficiency
To generate the swirl, the intake port should be serpentine design. This makes the resistance in air
flow. The resistance in air flow in engine high speed decreases the intake efficiency. Eventually, the
engine power is also decreased, Thus, the swirl operation is deactivated in high speed range to
increase the intake efficiency.
Relationship between swirl and EGR
To reduce Nox, it is essential to increase EGR ratio. However, if EGR ratio is too high, the PM also
could be very higher. And, the exhaust gas should be evenly mixed with newly aspired air. Otherwise,
PM and CO are dramatically increased in highly concentrated exhaust gas range and EGR ratio
could not be increased beyond a certain limit. If the swirl valve operates in this moment, the limit of
EGR ratio will be higher. -
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F. Relationship between swirl and fuel injection pressure
The injector for DI engine uses the multi hole design. For this vehicle, there are 8 holes in injector. If the
swirl is too strong, the injection angles might be overlapped and may cause the increased PM and
insufficient engine power. Also, if the injection pressure is too high during strong swirl, the injection
angles might be overlapped. Therefore, the system may decreases the fuel injection pressure when the
swirl is too strong.

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(9) EGR control
A. Overview
The EGR (Electric-Exhaust Gas Recirculation) valve reduces the NOx emission level by recirculating
some of the exhaust gas to the intake system.
To meet Euro-V regulation, the capacity and response rate of E-EGR valve in D20DTR engine have
been greatly improved. The EGR cooler with high capacity reduces the Nox, and the bypass valve
reduces the CO and HC due to EGR gas before warming up.
Also, the engine ECU adjusts the E-EGR opening by using the air mass signal through HFM sensor. If
the exhaust gas gets into the intake manifold when the EGR valve is open, the amount of fresh air
through HFM sensor should be decresed.
B. Components
E-EGR cooler
Accelerator pedal
moduleD20DTR ECU
Coolant
temperature
sensorOxygen sensor
HFM (intake air
temperature)Electric throttle
body
Crankshaft
position sensorE-EGR valve
T-MAP sensor

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C. Input/Output of E-EGR system

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D. Bypass control for EGR cooler
Cooler temperature ▶
<007e008f008c00950047009b008f008c0047008a00960096009300880095009b0047009b008c00940097008c00990088009b009c0099008c00470090009a00470089008c00930096009e0047005e00570b4500530047009b008f008c0047008c009f008f00
88009c009a009b0047008e0088009a00470090009a00470089>ypassed the EGR cooler.
Exhaust gas temperature ▶
<007e008f008c00950047009b008f008c0047008c009f008f0088009c009a009b0047008e0088009a0047009b008c00940097008c00990088009b009c0099008c00470090009a00470089008c00930096009e0047005a005700570b4500530047009b008f00
8c0047008c009f008f0088009c009a009b0047008e0088009a> is bypassed the EGR cooler.
Otherwise, PM could be increased due to too low exhaust gas temperature.
E. Control elements for EGR system
Accelerator pedal (engine load) - Indicates the driver's intention and engine load. If the load goes up,
the EGR ratio is decreased.
T-MAP (boost pressure map stored in ECU) - Compensates the difference in boost pressure by
adjusting EGR ratio.
Engine rpm - Used as the signal for determining EGR operating range.
Coolant temperature - When the coolant temperature is low, NOx is decreased but PM could be
increased. So, to reduce PM, decrease EGR ratio when the coolant temperature is low.
Intake air mass and temperature - HFM sensor measures the intake air mass to calculate the actual
EGR volume. If the air mass is larger than programmed value in map, EGR ratio will be higher.
EGR position sensor - Detects the actual opening angle of EGR valve and performs feedback
function according to PWM control by ECU.
Wide band oxygen sensor - Detects the oxygen volume in exhaust gas to check if the EGR ratio is
proper.
Electronic throttle body - Keeps EGR ratio to optimized level by controlling the throttle body in EGR
operating range (decreasing pressure in intake manifold). -
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F. Features
As EGR ratio goes up, smoke volume will be
higher. But, this lowers the combustion
chamber temperature and accordingly the
concentration of NOx is decreased. The point
with highest NOx is immediately after TDC.As EGR temperature goes up, the
concentration of NOx will be higher. Thus, it is
necessary to cool down the exhaust gas.
However, during engine cooled, it may cause
large amount of PM. To prevent this, the
exhaust gas is bypassed the EGR cooler.