Features; Swirl And Air Intake Efficiency; Relationship Between Swirl And Egr; Relationship Between Swirl And Fuel Injection Pressure - SSANGYONG Korando 2012 Manual

Hide thumbs Also See for Korando 2012:

Table of Contents

Engine speed

below 3,000 rpm

over 3,000 rpm

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

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.

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.

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

Increased EGR ratio, better air-fuel

mixture (reduce exhaust gas)

Increase 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.