Page 241 of 796

04-10
1) 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
Squish: Squish is the air flows due to the piston head. Normally, this is
appears at the final process of compression. In CRDi engine, the
piston head creates the bowl type squish.
2) 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.
Page 242 of 796

04-111719-00
LoadEngine
speedSwirl valve Amount of
swirlRemarks
Low speed,
Low loadbelow 3,000
rpmClosed HeavyIncreased EGR ratio, better air-fuel
mixture (reduce exhaust gas)
High speed,
High loadover 3,000
rpmOpen 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
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 243 of 796
05-31729-01
Muffler Assembly
1. MAJOR CHANGES
Muffler assembly parts (A, B) changed due to change of rear subframe
(A) Connecting pipe between muffler and tail silencer: moved by 20 mm
(B) Gap between tail silencer pipe and body: changed from 16 mm to 25 mm -
Page 244 of 796
05-4
2. TROUBLESHOOTING
1) Work Flow
Page 245 of 796

05-51729-01
3. 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. -
-
-
-
-
-
-
-
Page 246 of 796
05-6
2. LAYOUT
Silencer Assembly
Exhaust manifold assembly
CDPF assembly
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.
Exhaust front pipe assembly
For more information, refer to Chapter
"Engine Control". *
Page 247 of 796
05-71729-01
3. OPERATING PROCESS
1) Exhaust Gas Flow
2) Input & Output Devices
Page 248 of 796
06-31914-01
1. SPECIFICATION
Unit Description Specification
TurbochargerMax. expansion coefficient 4.0
Max. turbine speed 226,000rpm
Max. temperature of turbine
housing790 ℃
Weight 6.5kg
E-VGT actuator Operation duty cycle 250Hz
E-VGT turbocharger ▶
Plate
Impeller
Turbine
Unison ring
Turbine housingCompressor
housing
E-VGT actuator