Diesel Exhaust Fluid (DEF) is a colorless, non-toxic liquid composed of 32.5% high-purity urea and 67.5% deionized water. It is used in diesel vehicles equipped with Selective Catalytic Reduction (SCR) systems to reduce harmful nitrogen oxide (NOx) emissions produced during diesel combustion. DEF works by being injected into the exhaust stream, where it reacts chemically to break down NOx gases into harmless nitrogen and water vapor, which are then released into the atmosphere. This process helps diesel engines meet environmental standards by significantly reducing air pollution. DEF is commonly used in trucks, buses, construction equipment, and agricultural machinery that have SCR technology. It is essential for cleaner and more efficient diesel engine operation and helps comply with emissions regulations. The fluid is sometimes called AUS 32 or marketed under trademark names like AdBlue. In summary, DEF is a crucial fluid that helps reduce air pollution from diesel engines by converting harmful emissions into safer substances through a catalytic chemical reaction. It is primarily made of urea and purified water to ensure effectiveness and protect engine components.
