Diesel Exhaust Fluid (DEF) consumption in modern diesel trucks is directly related to fuel consumption. A typical consumption rate is approximately 2-3% of the fuel used. For example, a truck consuming 100 gallons of diesel fuel would likely require 2-3 gallons of DEF. Various factors influence this ratio, including driving conditions, engine load, and ambient temperature.
Maintaining adequate DEF levels is essential for compliance with emissions regulations designed to reduce harmful nitrogen oxides (NOx) in diesel exhaust. DEF enables the Selective Catalytic Reduction (SCR) system to convert NOx into harmless nitrogen and water vapor. Ignoring DEF requirements can lead to reduced engine power, system malfunctions, and ultimately, vehicle shutdown. This technology has become increasingly important since the introduction of stricter emissions standards for heavy-duty vehicles.