GENERAL INFORMATION (EXHAUST GAS RECIRCULATION SYSTEM)
The exhaust gas recirculation system lowers the nitrogen oxide (NOx) emission level.
When the air/fuel mixture combustion temperature is high, a large quantity of nitrogen oxides (NOx) is generated in the combustion chamber.
Therefore, this system recirculates part of emission gas from the exhaust port of the cylinder head to the combustion chamber through the inlet manifold to decrease the air/fuel mixture combustion temperature, resulting in reduction of NOx.
The exhaust gas recirculation flow rate is controlled by the exhaust gas recirculation valve so as not to decrease the driveability.
OPERATION
The exhaust gas recirculation valve is being closed and does not recirculate exhaust gases under one of the following conditions.
Otherwise, the exhaust gas recirculation valve is opened and recirculates exhaust gases.
- The engine coolant temperature is low.
- The engine is at idle.
- The throttle valve is widely opened.