What is SCR technology for trucks, buses and off road heavy duty vehicles?
SCR stands for an after treatment technology called Selective Catalytic Reduction. This technology requires the use of a reagent called AUS 32 (also known as AdBlue, DEF in North America or ARLA 32 in Brazil) to reduce the NOx. Almost all major heavy-duty vehicles manufacturers have decided to use this technology to meet the new emission legislation on NOx emissions. Competitive technologies offer a less beneficial fuel efficiency and higher CO2 emissions. So SCR is the most cost effective solution to meet NOx emission standards.
The main components of the SCR system are the SCR catalyst, the AdBlue injection unit, the AdBlue tank and the AdBlue dosing control unit. AdBlue is injected into the exhaust pipe, in front of the SCR catalyst, downstream of the engine. Heated in the exhaust it decomposes into ammonia and CO2. When the NOx reacts inside the catalyst with the ammonia, the harmful NOx molecules in the exhaust are converted to harmless nitrogen and water.
For the correct functioning of your SCR system, make sure you use only high quality AdBlue such as Air1. Poor quality reagent that is contaminated with foreign matters risks damaging your catalyst.
SCR is already a proven technology and one which will be relied on in the future. It will be used for the forthcoming Euro VI standard.