SCR technology consists in converting (reducing) nitrogen oxides into non-toxic nitrogen and water vapor in a catalyst using ammonia as a reducer. In commercial vehicles, a non-toxic, odorless, 32.5% aqueous solution of urea is used. Under the control of the engine management system, the urea solution (NOX), stored in a separate tank, is dosed in the desired amounts into the hot exhaust stream. Under high temperature exhaust gases, the urea solution decomposes to ammonia and carbon dioxide. Ammonia then reacts with nitrogen oxides to form free nitrogen and water vapor.

Denoxtronic Bosch systems have been used since 2004 in trucks equipped with diesel power systems. They add AdBlue to the SCR catalyst to reduce NOx emissions from exhaust gases by up to 85%. As a result, lorries meet the exhaust emission standards from Euro 4 to Euro 6.