Diesel Exhaust Fluid
Diesel Exhaust Fluid (DEF) is an operating fluid for Selective Catalytic Reduction (SCR) technology, which is used in new heavy-duty commercial vehicles. DEF is not a fuel or fuel additive. It is injected into the exhaust system to chemically reduce NOx emissions from diesel powered vehicles. DEF is a high-purity urea solution complying with the Standards of ISO 22241. This is the highest quality and safety standard in place which ensures the correct functioning of Selective Catalytic Reduction equipment.
1) What is DEF?
Diesel exhaust fluid, commonly referred to as DEF, is a solution of 67.5% deionized water and 32.5% high-purity urea, that’s used to chemically reduce nitrogen oxides emissions (NOx) from Heavy vehicle, non-road mobile machinery and heavy equipment.
Just as important as knowing what DEF is – knowing what it’s not:
DEF is not a fuel additive.
DEF is not toxic or harmful to humans or animals.
DEF is not flammable or explosive.
2) How does DEF work?
DEF is used in diesel engines with Selective Catalytic Reduction (SCR) systems. SCR is an after-treatment technology that treats exhaust gas downstream of the engine, with the goal of reducing levels of NOx emissions that are harmful to the environment and health. DEF is injected into the exhaust stream, prior to the SCR catalyst, and converts NOx into harmless nitrogen and water.
3) Why does my equipment need DEF?
All BS-VI engines are equipped with SCR systems. Not only does this technology work with DEF to reduce NOx, the SCR process allows engines to operate at maximum efficiency for better fuel economy and lower costs.
4) How do I use DEF?
Although its name may imply otherwise, DEF should never be used in the diesel fuel tank. It should only be used in the appropriate, dedicated DEF tank, which features a smaller opening than a fuel tank.
5) How much DEF can I expect my equipment to use?
Every engine varies in its use of DEF. Typical DEF use is 1-3% of fuel consumed. So for every 100 Litres of diesel fuel consumed approximately 2 Litres of DEF would be needed.