Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
67
Section IX EGR System
The exhaust gas recirculation (EGR) introduces one small portion of exhaust gas from the exhaust pipe into the intake
pipe that is mixed with the fresh intake air to artificially increase the exhaust amount in the fresh intake air and thus
reduce the combustion temperature of engine and reduce the formation of NOx.
z The NOx is increased following the increasing of engine load and the EGR ratio shall increase accordingly.
z The EGR is not be performed when the engine coolant temperature is low;
z The EGR is not performed under idling or low load, as the NOx emission is not high in such case.
z The EGR is not performed under full load or acceleration;
z The water-cooled EGR further reduces the temperature of exhaust gas entering into the cylinder and further
reduces the emission of NOx.
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