SSANGYONG Korando 2012 Manual page 324

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d. Bypass control for EGR cooler
1. Cooler temperature
When the coolant temperature is below 70℃, the exhaust gas is bypassed the EGR cooler.
2. Exhaust gas temperature
When the exhaust gas temperature is below 300℃, the exhaust gas is bypassed the EGR cooler.
Otherwise, PM could be increased due to too low exhaust gas temperature.
e. Control elements for EGR system
- Accelerator pedal (engine load) - Indicates the driver's intention and engine load. If the load
goes up, the EGR ratio is decreased.
- T-MAP (boost pressure map stored in ECU) - Compensates the difference in boost pressure
by adjusting EGR ratio.
- Engine rpm - Used as the signal for determining EGR operating range.
- Coolant temperature - When the coolant temperature is low, NOx is decreased but PM could
be increased. So, to reduce PM, decrease EGR ratio when the coolant temperature is low.
- Intake air mass and temperature - HFM sensor measures the intake air mass to calculate the
actual EGR volume. If the air mass is larger than programmed value in map, EGR ratio will be
higher.
- EGR position sensor - Detects the actual opening angle of EGR valve and performs feedback
function according to PWM control by ECU.
- Wide band oxygen sensor - Detects the oxygen volume in exhaust gas to check if the EGR
ratio is proper.
- Electronic throttle body - Keeps EGR ratio to optimized level by controlling the throttle body in
EGR operating range (decreasing pressure in intake manifold).