SSANGYONG Rodius 2012.07 Manual page 355

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D. Bypass control for EGR cooler
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Cooler temperature
When the coolant temperature is below 70℃, the exhaust gas is bypassed the EGR cooler.
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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).