Diesel Exhaust Fluid (DEF) is the key consumable element of the Selective Catalytic Reduction (SCR) process used by almost all medium and heavy-duty diesel engine builders to meet stringent 2010 government regulations for NOx emissions.
DEF is a non-toxic solution of 67.5% purified water and 32.5% ultra pure automotive grade urea. DEF is injected into the exhaust stream and passed over a catalyst, helping to convert NOx into harmless and abundant nitrogen gas and water vapour.
DEF is a stable, colorless and odourless liquid, meeting rigid ISO 22241 standards for purity and composition and is an American Petroleum Institute (API) certified diesel exhaust fluid. These are universally recognized quality and purity standards implemented to ensure optimum and standardized SCR performance.
Diesel Exhaust Fluid (DEF) is the key consumable element of the Selective Catalytic Reduction (SCR) process used by almost all medium and heavy-duty diesel engine builders to meet stringent 2010 government regulations for NOx emissions.
DEF is a non-toxic solution of 67.5% purified water and 32.5% ultra pure automotive grade urea. DEF is injected into the exhaust stream and passed over a catalyst, helping to convert NOx into harmless and abundant nitrogen gas and water vapour.
DEF is a stable, colorless and odourless liquid, meeting rigid ISO 22241 standards for purity and composition and is an American Petroleum Institute (API) certified diesel exhaust fluid. These are universally recognized quality and purity standards implemented to ensure optimum and standardized SCR performance.
Diesel Exhaust Fluid (DEF) is misted into the diesel exhaust stream, downstream of the Diesel Particulate Filter (DPF). Sensors in the exhaust tell the DEF metering system what concentration of NOx is present in the exhaust stream, and meters the optimum amount of product required to neutralize the gas. The co-mingled exhaust-DEF solution then enters into the SCR Catalyst, where the DEF hydrolyzes into ammonia and reacts chemically with the NOx molecules present in the exhaust stream. The SCR catalyst allows the NOx and ammonia to break down and form two different compounds; harmless nitrogen gas and water vapour.
DEF is consumed at a rate of 2-4% of your average fuel consumption.
Chemical reaction: NO+NO2+2NH3 = 2N2+3H2O
The steps used to manufacture DEF are:
Almost all 2010 and newer medium and heavy duty diesel trucks, as well as diesel pickups and cars, require DEF.
Most SCR equipped engines that use DEF are also utilizing other clean-air technology (DPF & EGR) that burden’s the engine’s power output and fuel economy. This technology was utilized as an 'in cylinder' solution to reduce particulate matter and NOx in previous generation engines. Though these technologies were successful, they came at the price of engine efficiency.
With the introduction of the SCR system, the amount that these previous technologies are utilized within the engine is greatly reduced, allowing for an increase in power, and an increase in fuel economy.
On average, engines utilizing SCR technology are benefiting from a 5% increase in power and fuel economy over the previous generation engines. In addition to the power and efficiency benefits, it also reduces the NOx emissions to nearly zero, for minimal environmental impact!
NOx Free wants to make it easy for you to learn more about DEF. NOx Free has assembled an extensive list of FAQs for your convenience.
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