Functional principle of the SCR system

SCR technology has established itself globally as a method of reducing nitrogen oxides in exhaust gas. Currently it is the most commonly used technology for complying with the European Euro 4, 5 and 6 standards as well as the American EPA 10 and Tier 4 Final standards for commercial vehicles. SCR is an abbreviation for Selective Catalytic Reduction. Since 2005, this method is used in series-produced European commercial vehicles. In countries such as China and India, manufacturers of commercial vehicles are also increasingly implementing this technology to meet the limit values set by emission standards.

The SCR method involves injecting the AdBlue/DEF reducing agent, an aqueous urea solution, into the exhaust tract. In the exhaust gas, it is broken down into ammonia, with which the nitrogen oxides are reduced at the  SCR catalyst and are

converted to harmless nitrogen and water. Vehicles that are equipped with the SCR system therefore have an additional tank for the reducing agent. The consumption of AdBlue/DEF amounts to approx. four to five percent of the fuel consumption. 

SCR systems have to be designed as compact units that fit into the installation space of the mufflers. The systems combine exhaust gas treatment with SCR technology and sound muffling into one housing. As part of the SCR procedure, AdBlue/DEF is injected directly into the exhaust tract by means of a Urea Dosing System. For the SCR catalysts to obtain the best possible results, it is vital that the AdBlue/DEF is atomized as finely as possible when it is being injected into the exhaust tract. The entire procedure is electronically controlled by the Aftertreatment Control Unit.

Datasheet Albonair