diesel exhaust fluid

Diesel Exhaust Fluid (DEF) is a clear, non-toxic liquid made from water and urea, used in diesel engines equipped with selective catalytic reduction (SCR) systems. Its purpose is to reduce harmful emissions of nitrogen oxides (NOx), which contribute to pollution and smog. The DEF is injected into the exhaust stream, where it reacts with NOx to convert them into harmless nitrogen and water vapor. Properly used, DEF helps diesel engines meet environmental regulations while maintaining efficiency. It needs to be regularly refilled, much like fuel, to ensure the emissions control system functions effectively.