Niagara Gazette — Ultra low sulfur diesel
Diesel fuel has historically contained a lot of sulfur, which is a naturally occurring element in crude oil. Sulfur dioxide emissions in diesel exhaust have been a primary contributor to the engine’s reputation as a smelly power plant, additionally sulfur emissions react with moisture in the atmosphere to form sulfuric acid rain.
As recently as 2006, the Low Sulfur Diesel (LSD) fuel sold for on-highway use contained up to 500 parts per million (ppm) of sulfur. Even at this level, the sulfur content in diesel fuel created harmful emissions and exhaust system deposits that prevented the use of advanced emission control equipment such as catalytic converters. To address these concerns and help meet increasingly stringent emission control requirements, Ultra Low Sulfur Diesel (ULSD) fuel containing less than 15 ppm of sulfur was introduced beginning in 2006. Today, all 2007 and later diesel engines in on-road vehicles must use ULSD and have instrument panel and fuel filler labeling expressing this requirement. Federal regulations also require the labeling of diesel pumps at gasoline stations to identify the type of fuel being dispensed. Use of anything other than ULSD in a 2007 or newer vehicle will reduce engine efficiency, fuel economy, and durability, and may prevent engine operation. In addition, fuels other than ULSD will damage advanced emission control systems and void the vehicle manufacturers warranty on any affected engine, fuel and exhaust system components.
Because sulfur is a natural lubricant, one concern raised during the transition to ULSD fuels was that increased engine wear might result. Engine manufacturers responded by “hardening” components that might be subject to greater wear, special motor oils have been developed for diesel engines that use ULSD and fuel providers now blend additional lubricity agents into diesel fuel. For those who operate older diesel engines and have concerns about the impact of using ULSD, aftermarket fuel additives are available to increase engine and fuel system protection. However, the use of diesel fuel additives should always be in accordance with the vehicle manufacturer’s recommendations.