SSANGYONG Korando 2012 Manual page 320

15-22
Load Engine speed
Low speed,
below 3,000 rpm
Low load
High speed,
over 3,000 rpm
High load
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.
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 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.
Swirl Amount of
valve swirl
Increased EGR ratio, better air-fuel
Closed Heavy
mixture (reduce exhaust gas)
Increase charge efficiency, higher
Open Light
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.
Remarks