This article explains how DEF (Diesel Exhaust Fluid) works in conjunction with the SCR in diesel engines and how the EPA regulations affect truck owners.

Diesel exhaust fluid (DEF; also known as AUS 32 and sometimes marketed as AdBlue[3]) is a liquid used to reduce the amount of air pollution created by a diesel engine. Specifically, DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water.

Jul 29, 2024 · Diesel exhaust fluid, or DEF, is a key component in lowering pollutants emitted from diesel engines, helping to improve efficiency and reduce emissions.

Mar 18, 2025 · The use of DEF in diesel engines provides several advantages: Reduced Emissions: DEF significantly lowers NOx emissions, helping engines meet EPA standards. Improved Fuel Efficiency: By optimizing the combustion process, DEF can enhance overall fuel economy. Engine Longevity: Lower emissions can lead to …

How Does DEF Work? As a compound, nitrogen turns to ammonia when heated. The aftertreatment system introduces ammonia given up from the urea found in DEF to initiate a chemical reaction to clean up the exhaust system NOx.

Feb 10, 2025 · Learn everything you need to know about diesel exhaust fluid (DEF), how it works, and how to choose the best DEF fluid for your truck to keep it running smoothly.

Oct 19, 2023 · Diesel Exhaust Fluid (DEF) is a crucial component for companies using heavy-duty diesel engines to keep their vehicles and machinery within federal emission guidelines. But how does DEF work, and how can you prevent it from going bad?

Apr 2, 2024 · Diesel Exhaust Fluid primarily reduces nitrogen oxides emissions in diesel engines through a process called Selective Catalytic Reduction. In the presence of the catalyst, ammonia reacts with nitrogen oxides (NOx) in the exhaust gas. The reaction converts NOx into nitrogen (N₂) and water vapor (H₂O).

Dec 18, 2023 · Diesel exhaust fluid, or DEF, is a chemical additive that reduces emissions. It’s also known as AdBlue in Europe and Canada and Diesel Exhaust Fluid (DEF) in the United States. DEF is an aqueous solution of 32% urea and 68% deionized water that catalyzes NOx reduction during combustion.

Feb 25, 2025 · DEF is a clear, non-toxic liquid made from a mixture of urea and deionized water. It’s injected into the exhaust stream of modern diesel engines to reduce harmful nitrogen oxide (NOx) emissions.