SSANGYONG Korando 2012 Manual page 406

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.
Harmful materials produced in the combustion process is treated and reduced in the exhaust
system. Harmful materials discharged from the crankcase and fuel tank is drawn into the intake
system again to reduce discharge amount of harmful materials.
▶ Emission aftertreatment system
- Catalytic Converter & O2 Sensor
The catalytic converter is a monolith type purification system composed of cordierite which
purifies exhaust gas through the small holes of active monolith catalyst from the exhaust
manifold. As exhaust gas passes through the small holes in the layer in the middle, its CO and
HC are reduced by oxidization reaction and its NOx is reduced by reduction reaction to Pt, Ph
and Pd. The oxygen sensor sends signals for feedback and determination of catalyst
condition. For detailed description, see the corresponding section.
▶ Purge Canister Control
The fuel evaporative gas is a gas evaporated to the atmosphere in the section between the fuel
tank and fuel line, and its main component is hydrocarbon (HC). The fuel evaporative gas is
temporarily stored in the canister, and it is drawn to the engine through the throttle body when the
purge control solenoid valve is open according to the engine operating condition.
▶ Blow-by gas control system (crankcase ventilation system)
Gas in the combustion chamber is sealed by the piston. However, gas is leaked through the gap
between the cylinder and piston and drawn into the crankcase during the compression and
explosion strokes. This gas is blow-by gas and its main components are hydrocarbon and
carbon monoxide. If this gas is drawn into the crankcase, the system can be corroded and oil
can be deteriorated. Also, if this gas is discharged into the air, it can pollute the environment. To
prevent these, the blow-by gas reduction system (also called as crankcase ventilation system)
draws the blow-by gas from the crankcase to the combustion chamber for combustion.
05-7
1745-01