Diesel Exhaust Fluid: Notes
The diesel exhaust fluid (DEF) is a urea-water solution which acts as a the carrier for the ammonia that is used to reduce the nitrogen oxides (NOx ) in the exhaust gas.
To protect persons and the environment from the effects of ammonia and to make it more easy to handle for transport and refuelling procedures, it is provided in an aqueous urea solution for the SCR process.
The recommended urea-water solution must meet certain standards for quality which are set forth in accordance with the DIN 70070/AUS32.
The DEF is a high-purity, water-clear, synthetically manufactured solution consisting of 32.5% urea with the balance being water (67.5%). The urea-water solution used must correspond to this standard.