Diesel Exhaust Fluid (DEF) is a critical component in modern diesel engines equipped with Selective Catalytic Reduction (SCR) systems. It helps vehicles meet strict emissions regulations while reducing harmful nitrogen oxide (NOx) emissions.
What is DEF?
- Also known as urea: DEF is a solution of high-purity urea and deionized water.
- Purpose: When injected into a diesel engine’s exhaust stream, DEF reacts with NOx gases in the SCR catalyst to convert them into harmless nitrogen and water vapor.
- Non-toxic and safe: Current DEF formulations are colorless, odorless, and safe to handle.
How DEF Works in Diesel Engines
- The SCR system monitors exhaust gases for NOx levels.
- DEF is injected into the exhaust stream as a fine mist.
- Inside the SCR catalyst, urea in DEF converts to ammonia, which reacts with NOx to form nitrogen and water.
- The result is cleaner exhaust and compliance with emissions standards.
DEF Formulation and Safety
- Composition: Typically 32.5% high-purity urea and 67.5% deionized water.
- Source of urea: Naturally occurring or manufactured from natural gas.
- Storage: DEF is sensitive to temperature; it should be stored in a cool, dry place away from direct sunlight. Freezing does not damage it, but it must be thawed before use.
Industries Using DEF
- Heavy-duty trucking
- Buses and public transit
- Construction and mining equipment
- Agricultural machinery
- Marine diesel engines
Why DEF Matters
- Emissions compliance: DEF is essential for meeting EPA and other global NOx emission standards.
- Environmental benefits: Reduces air pollution from diesel engines by converting harmful NOx into harmless nitrogen and water.
- Engine efficiency: Proper use of DEF allows engines to maintain high performance while lowering emissions.
SafeRack & DEF Handling
While DEF is non-toxic, proper handling, storage, and dispensing are important in industrial and transportation settings. Explore our fuel and chemical tank solutions for safe fluid storage and management.
DEF reduces harmful nitrogen oxide (NOx) emissions by reacting with exhaust gases in the SCR system to form nitrogen and water.
Yes, DEF is non-toxic, colorless, and odorless, but it should be stored properly to prevent contamination.
Yes, DEF can freeze, but it will thaw without damage. DEF should be used only when thawed.
DEF is made from high-purity urea, which can be naturally occurring or manufactured from natural gas.
DEF is used in heavy-duty trucks, buses, construction equipment, agricultural machinery, and marine diesel engines.
