Page 174 of 1082

04-110000-00
Load Engine 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 valve
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.
3) 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. -
-
4) 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.
Page 177 of 1082

05-4
2. CAUTIONS
Do not park the vehicle on flammable materials, such as grass, leaves and carpet.
Do not touch the catalyst or the exhaust gas ignition system when the engine is running.
If a misfire occurs in the combustion chamber or the emission of pollutant exceeds the specified
level, the catalyst can be damaged.
When servicing or replacing components of the exhaust system, makes sure that the components
are positioned at regular intervals from all other parts of the under body.
Be careful not to damage the exhaust system when lifting the vehicle from its side.
All components and body parts of the engine exhaust system should be inspected for crack,
damage, air hole, part loss and incorrect mounting location. Also check for any deformation which
can result in exhaust gas drawn into the vehicle.
Make sure that the exhaust pipe is cooled down sufficiently before working on it because it is still hot
right after the engine is stopped.
Wear protective gloves when removing the exhaust pipe. -
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-
-
-
-
-
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05-50000-00
Exhaust manifoldCDPF assembly
No. 1 exhaust pipe
No. 2 exhaust pipe
No.3 muffler pipe
1. OVERVIEW
This system purifies the exhaust gas generated by the combustion in the engine to reduce the pollutants
and noise during that arise during combustion.
2. COMPONENT
Fore details about the CDPF
assembly, refer to Chapter
"CDPF System".
Page 181 of 1082

06-4
2. INSPECTION
1) Cautions During Driving
The following lists cautions to take during test drive and on the turbocharger vehicle, which must be
considered during the operation.
It's important not to drastically increase the engine rpm starting the engine. It could make rotation at
excessive speed even before the journal bearing is lubricated and when the turbocharger rotates in
poor oil supply condition, it could cause damage of bearing seizure within few seconds.
If the engine is running radically after replacing the engine oil or oil filter brings poor oil supply
condition. To avoid this, it's necessary to start off after idling the engine for about 1 minute allowing oil
to circulate to the turbocharger after the replacement.
When the engine is stopped abruptly after driving at high speed, the turbocharger continues to rotate
in condition where the oil pressure is at '0'. In such condition, an oil film between the journal bearing
and the housing shaft journal section gets broken and this causes abrasion of the journal bearing due
to the rapid contact. The repeat of such condition significantly reduces life of the turbocharger.
Therefore, the engine should be stopped possibly in the idle condition. 1.
2.
3.
After string for long period of time during winter season or in the low temperature condition where
the fluidity of engine oil declines, the engine, before being started, should be cranked to circulate oil
and must drive after checking the oil pressure is in normal condition by idling the engine for few
minutes.
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06-50000-00
2) Inspection of Turbocharger
On-board Inspection 1.
Check the bolts and nuts foe looseness or missing
Check the intake and exhaust manifold for looseness or damage
Check the oil supply pipe and drain pipe for damages
Check the housing for crack and deterioration -
-
-
-
Inspection of turbine 2.
Remove the exhaust pipe at the opening of the turbine and check, with a lamp, the existence of
interference of housing and wheel, oil leakage and contamination (at blade edge) of foreign
materials.
Interference: In case where the oil leak sign exists, even the small traces of interferences on the
turbine wheel mean, most of times, that abrasion has occurred on the journal bearing. Must
inspect after overhauling the turbocharger.
Oil Leakage: Followings are the reasons for oil leakage condition -
-
Problems in engine: In case where the oil is smeared on inner wall section of the exhaust gas
opening.
Problems in turbocharger: In case where the oil is smeared on only at the exhaust gas
outlet section. *
* When problem occurs with the turbocharger, it could cause engine power decline,
excessive discharge of exhaust gas, outbreak of abnormal noise and excessive
consumption of oil.
Idling for long period of time can cause oil leakage to the turbine side due to low pressure of
exhaust gas and the rotation speed of turbine wheel. Please note this is not a turbocharger
problem.
Oil Drain Pipe Defect
In case where oil flow from the turbocharger sensor housing to the crank case is not smooth would
become the reason for leakage as oil builds up within the center housing. Also, oil thickens (sludge)
at high temperature and becomes the indirect reason of wheel hub section. In such case, clogging
and damage of the oil drain pipe and the pressure of blow-by gas within the crank case must be
inspected.
Damages due to Foreign Materials
When the foreign materials get into the system, it could induce inner damage as rotating balance of
the turbocharger gets out of alignment. -
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Page 183 of 1082

06-6
3) Inspection of Turbine
Thoroughly check the followings.
Interference: In case where is trace of interference or smallest damage on the compressor wheel
means, most of times, that abrasion has occurred on the journal bearing. Must inspect after the
overhaul.
Oil Leakage: The reason for oil leakage at the compressor section is the air cleaner, clogged by
substances such as dust, causes the compressor inlet negative pressure. -
-
Rotating in high speed at no-load for extended period of time can cause oil leakage to the
compressor section as oil pressure within the center housing gets higher than pressure within the
compressor housing.
Overuse of engine break (especially in low gear) in down hill makes significantly low exhaust gas
energy compared to the time where great amount of air is required during idling conditions of the
engine. Therefore, amount of air in the compressor inlet increases but the turbocharge pressure
is not high, which makes negative pressure at the compressor section causing the oilleakage
within the center housing. a.
b.
No problem will occur with the turbocharger if above conditions are found in early stage but oil
leaked over long period of time will solidify at each section causing to breakout secondary
defects.
Damages by foreign materials: In case where the compressor wheel is damaged by foreign materials
requires having an overhaul. At this time, it's necessary to check whether the foreign materials have
contaminated intake/exhaust manifold or inside of engine.
Must absolutely not operate the turbocharger with the compressor outlet and inlet opened
as it could damage the turbocharger or be hazardous during inspection.
Page 186 of 1082
06-90000-00
Turbine Side: Inflow of foreign materials from engine
Compressor Side: such as air filter, muffler and nut 3.
Page 188 of 1082

06-110000-00
3. TROUBLESHOOTING
The followings are cautions to take in handling defects of turbocharger, which must be fully aware of.
1) Cautions
After stopping the engine, check whether the bolts on pipe connecting section are
loose as well as the connecting condition of vacuum port and modulator, which is
connected to the actuator.
During idling of the engine, check for leakage in the connecting section of pipe (hoses
and pipes, duct connections, after the turbocharger) by applying soap water. The
leakage condition in the engine block and turbine housing opening can be determined
by the occurrence of abnormal noise of exhaust.
By running the engine at idle speed, abnormal vibration and noise can be checked.
Immediately stop the engine when abnormal vibration and noise is detected and make
thorough inspection whether the turbocharger shaft wheel has any damages as well as
checking the condition of connections between pipes.
In case where the noise of engine is louder than usual, there is possibility of dampness
in the areas related with air cleaner and engine or engine block and turbocharger. And
it could affect the smooth supply of engine oil and discharge.
Check for damp condition in exhaust gas when there is sign of thermal discoloration or
discharge of carbon in connecting area of the duct.
When the engine rotates or in case where there is change in noise level, check for
clogging of air cleaner or air cleaner duct or if there is any significant amount of dust in
the compressor housing.
During the inspection of center housing, inspect inside of the housing by removing the
oil drain pipe to check for sludge generation and its attachment condition at shaft area
or turbine side.
Inspect or replace the air cleaner when the compressor wheel is damaged by inflow of
foreign materials.
Inspect both side of the turbocharger wheel after removing inlet and outlet pipe of the
turbocharger.
- Is the rotation smooth when the rotor is rotated by hand?
- Is the movement of bearing normal?
- Inspect whether there has been any signs of interference between two wheels. 1.
2.
3.
4.
5.
6.
7.
8.
9.
It's important not to drive the engine when the intake manifold hose has been removed.