WHAT IS DEF or ADBLUE ?
Diesel engines are typically operated with a lean burn air-to-fuel ratio to ensure the full combustion of soot and to prevent them from exhausting unburnt fuel. The excess air leads to the generation of NOx, which are harmful pollutants, from nitrogen in the atmosphere.
Diesel exhaust fluid (DEF; also known as AUS 32 and marketed as AdBlue) is a liquid used to reduce the amount of air pollution created by a diesel engine. Specifically, DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water. DEF is consumed in a selective catalytic reduction (SCR) that lowers the concentration of Nitrogen Oxides in the diesel exhaust emissions from a diesel engine.
THE IMPORTANCE OF THE QUALITY OF DEF
Diesel Exhaust Fluid (DEF) is now commonplace – it’s found across industries using diesel powered engines in their equipment – on-highway, off-highway, mining equipment, severe service vehicles, and even consumer diesel powered vehicles. As DEF is a vital part of your engine and exhaust system, it should be treated like you treat all other engine oils – with proper handling procedures and regular testing.
Cleanliness specifications for DEF are extremely stringent. A small amount of metal contaminants such as copper, zinc, chromium, or nickel can contaminate an entire tanker truck of DEF. Trace amounts of these metals and other contaminants (e.g., iron, aluminum, phosphorus) can build up inside the SCR system and create a lot of problems.