AdBlue is used in addition to Selective Catalytic Reduction (SCR). SCR technology is used to reduce harmful emissions from diesel engines and the only way to meet upcoming Euro6 emission standards and 2010 EPA standards (North America). Most heavy duty manufactures have already implemented SCR technology.
SCR is a reliable way to clean up your engine. This exhaust aftertreatment technique converts nitrogen oxides (NOx) into diatomic nitrogen (N2) and water using ammonia or urea solutions. The first SCR systems were constructed for industrial use (in boilers). But as the technology became more advanced, SCR was used in diesel engines in the automotive industry. Trucks and busses were equipped with SCR, with great results. The latest developments in SCR technology involve applications for diesel locomotives, ships and gas turbines as well as farming equipment, construction equipment and refineries.
SCR engines use a Diesel Exhaust Fluid (DEF). AdBlue is a DEF. It is stored in a separate tank in the system and injected into the exhaust stream. This injection will cause a chemical reaction, which occurs in the SCR Catalytic Converter. Ultimately the potentially dangerous exhaust gas is converted into harmless nitrogen gas and water vapor, all thanks to AdBlue.