What Is The EPA’s Clean Diesel Program?
Over several years, the EPA has regulated vehicle emissions, mainly cars and light duty vehicles, since adopting the Clean Air Act in 1970. In 1990 the EPA began the National Clean Diesel Program to help improve air quality by achieving cleaner burning heavy duty diesel engines. The EPA addressed heavy duty diesel engines and the fuel they burn as one system to achieve a 90 percent reduction in overall pollution. Separate laws were put in place to regulate the composition of diesel fuel and require pollutant-specific sensitivity for exhaust treatment in heavy duty diesel engines.
Particulate matter (PM) or soot, and nitrogen oxide (NOx), are the main pollutants in diesel exhaust. New lower emission standards for PM and NOx for heavy duty diesel engines were phased into effect from 2007 to 2010. The National Clean Diesel Program also focuses on the sulfur content of diesel fuel and its effect on efficient treatment of diesel exhaust to meet the new diesel emission standards.
Sulfur occurs naturally in crude oil and has been present in diesel fuel at concentrations of up to 500 parts per million (ppm). High sulfur content in diesel fuel inhibits the ability of modern catalytic treatment systems to reduce PM and NOx emissions. Scientific studies show that as sulfur content of diesel fuel is reduced fuel consumption decreases and effectiveness of exhaust treatment increases.
EPA’s clean diesel program goal is a 97 percent reduction in sulfur content of diesel fuel to 15 ppm or less. As a result, refiners developed ultra-low sulfur diesel (ULSD) that became available in mid-2006. With the low sulfur content in the new ULSD diesel fuel, heavy duty diesel engine exhaust can be treated effectively to meet EPA’s lower emission standards.
How Does Diesel Exhaust Fluid Work?
DEF is solution of demineralized water and urea that is injected into the exhaust stream before it enters the SCR catalyst unit. At high heat the DEF vaporizes and becomes a mixture of ammonia and carbon dioxide. Ammonia is the “active ingredient” that reacts with NOx and produces non-toxic nitrogen and water. After SCR treatment the exhaust stream may be oxidized to treat any reacted ammonia in the final exhaust.
Many new heavy duty diesel vehicles come equipped with the SCR technology. SCR using DEF will result in lower maintenance costs and greater fuel efficiency without reducing your vehicles’ power. Retrofitting older heavy duty diesel vehicles is an important consideration since they may have an expected life of up to 30 years. Several retrofit options are available to reduce emissions including use of ULSD fuel, PM filters and oxidation catalysts.
Contact Innovative Fueling Solutions for more information about SCR and DEF technology. We offer services and equipment to the fuel storage and delivery industry. Our offices are located in Amarillo, Texas, and Clovis, New Mexico.