Product Brochure

With
the introduction of the latest Environmental Protection Agency emissions
levels limits in 2010, diesel engine manufacturers turned to a new
technology to clean up nitrogen oxides in the exhaust stream. Called selective catalytic
reduction (SCR), the exhaust aftertreatment system introduces ammonia from an aqueous
solution of automotive grade urea injected into the exhaust to clean up the NOx in the
following reaction:
Nh3 + NOx = N2 + h2O
While the chemical balance is not precise in this simplification, what is clear is that the
addition of ammonia results in the nitrogen oxides being reduced to nitrogen and water.
Since these are naturally occurring compounds in the air we breathe, it is a very elegant
way of cleaning up diesel exhaust.
While the technology is new to North America, it is a familiar process in Europe where
SCR has been used for diesel exhausts since the requirements of Euro 5 regulation in 2008.
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