Strategy implemented to control the emission of nitrogen oxides

Strategy implemented to control the emission of nitrogen oxides 

To satisfy new European regulations for the amount of NOx emissions, the car manufacturers used conversion systems on the diesel trucks. These systems are able to chemically transform gases into nitrogen. 

The process consists of injecting urea ahead of the catalyst, which is itself located before the exhaust pipe. 

The efficiency of such a device is linked to the quantity of urea injected, which depends on the quantity of NOx produced. 

In fact, too much urea in comparison to the quantity of NOx to treat leads to the formation of NH3 at the exit of the catalyzer. Conversely, not all the NOx can be converted and a part of this gas is found in the exhaust gases. 

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