What is Diesel Exhaust Fluid (DEF)?
Diesel exhaust fluid (DEF) is a urea-based solution that reduces harmful nitrogen oxide emissions from diesel engines. DEF is composed of 32.5% high-purity urea and 67.5% deionized water. DEF is clear, odorless and safe to handle.
The solution is added to a separate storage tank in diesel-powered vehicles equipped with selective catalytic reduction (SCR) technology. The fluid is injected into the hot exhaust stream of the vehicle and helps break down the nitrogen oxide gases in the exhaust into nitrogen gas and water vapor, both harmless to the environment.
Why Use DEF?
It is an inexpensive and efficient option for lowering NOx emissions. Nitrogen oxide (NOx) is produced from the exhaust of diesel vehicles and is a major contributor to smog and other air pollution. Exposure to NOx can also lead to respiratory and heart disease. This is why in 2010, the U.S. Environmental Protection Agency (EPA) mandated that all new diesel engine vehicles reduce NOx emission levels by 90%.
It improves engine performance and fuel efficiency. The combination of DEF and SCR technology not only reduces NOx emissions, it actually improves a vehicle’s horsepower by making diesel engines run more efficiently, resulting in fuel savings of up to 8%.
It is easy to use. Any diesel vehicle with SCR technology can use DEF. There are no special filters or absorbers required. The driver simply fills their DEF tank periodically and the SCR technology handles the rest. A gallon of diesel exhaust fluid costs about the same as a gallon of diesel fuel, but will generally last about 300-500 miles. And since the EPA regulations came into effect, SCR technology is quickly becoming the industry-standard on new diesel vehicles.
It is widely-available. Many truck stops now offer diesel exhaust fluid that can be pumped directly into the DEF tank. It can also be bought in easy-to-handle 2.5-gallon containers at auto stores, gas stations and other retailers. And fleet owners can purchase DEF in bulk storage with custom dispensing solutions.