Also known as: def.
DEF has various meanings in the Products category. Discover the full forms, definitions, and usage contexts of DEF in Products.
A quality control term describing a unit of product or service containing at least one defect or having several lesser imperfections that cause the unit not to fulfill its anticipated function.
ProductsSelective catalytic reduction (SCR) systems utilize DEF to reduce NOx. DEF is made up of 32.5 percent urea and 67.5 percent de-ionized water. The ammonia in the urea mixes with engine exhaust gases in the SCR catalyst to convert NOx to nitrogen and water vapor.
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