Reading a long article about ULSD here in the USA (Wikipedia) I thought I would share something that ties in with what VW says about addititive use in their 'clean diesel' models (09/10). If you don't want to read the entire page jump to the bottom and read that just below the dotted line.
Check it out below:
The EPA mandated the use of ULSD fuel in model year 2007 and newer highway diesel fuel engines equipped with advanced emission control systems that require the new fuel. These advanced emission control technologies will be required for marine diesel engines in 2014 and for locomotives in 2015.
The allowable sulfur content for ULSD (15
ppm) is much lower than the previous U.S. on-highway standard for low sulfur diesel (LSD, 500 ppm), which not only reduces emissions of sulfur compounds (a cause of
acid rain), but also allows advanced emission control systems to be fitted that would otherwise be poisoned by these compounds. These systems can greatly reduce emissions of
oxides of nitrogen and
particulate matter.
Because this grade of fuel is comparable to European grades and engines will no longer have to be redesigned to cope with higher sulfur content and may use advanced emissions control systems which can be damaged by sulfur, the ULSD standard is increasing the availability of diesel-fueled passenger cars in the U.S. In Europe, diesel-engined automobiles have been much more popular with buyers than has been the case in the U.S.
Additionally, the EPA is assisting manufacturers with the transition to tougher emissions regulations by loosening them for model year 2007 to 2010 light-duty diesel engines.
[5] As a result, Honda, Nissan, Subaru, Toyota, and others are expecting to begin producing diesel vehicles for the U.S. market to join those from Mercedes-Benz, Audi, Volkswagen, and BMW.
[6]
According to EPA estimates, with the implementation of the new fuel standards for diesel, nitrogen oxide emissions will be reduced by 2.6 million tons each year and soot or particulate matter will be reduced by 110,000 tons a year.
On June 1, 2006, U.S. refiners were required to produce 80% of their annual output as ULSD (15 ppm), and petroleum marketers and retailers were required to label
[7] diesel fuel, diesel fuel additives and kerosone pumps with EPA-authorized language disclosing fuel type and sulfur content. Other requirements effective June 1, 2006, including EPA-authorized language on Product Transfer Documents and sulfur-content testing standards, are designed to prevent misfueling, contamination by higher-sulfur fuels and liability issues. The EPA deadline for industry compliance to a 15 ppm sulfur content was originally set for July 15, 2006 for distribution terminals, and by September 1, 2006 for retail. But on November 8, 2005, the deadline was extended by 1.5 months to September 1, 2006 for terminals and October 15, 2006 for retail. In California, the extension was not granted and followed the original schedule. As of December, 2006, the ULSD standard has been in effect according to the amended schedule, and compliance at retail locations was reported to be in place.
Sulfur is not a
lubricant in of itself, but it can combine with the
nickel content in many metal alloys to form a low melting point
eutectic alloy that can increase lubricity. The process used to reduce the sulfur also reduces the fuel's lubricating properties. Lubricity is a measure of the fuel's ability to lubricate and protect the various parts of the engine's fuel injection system from wear. The processing required to reduce sulfur to 15 ppm also removes naturally-occurring lubricity agents in diesel fuel. To manage this change ASTM International (formerly the American Society for Testing and Materials) adopted the lubricity specification defined in ASTM D975 for all diesel fuels and this standard went into effect January 1, 2005.
[8]
The refining process that removes the sulfur also reduces the aromatic content and density of the fuel, resulting in a minor decrease in the energy content, by about 1%. This decrease in energy content may result in slightly reduced peak power and fuel economy.
The transition to ULSD is not without substantial costs. The US Government has estimated that pump prices for diesel fuel will increase between $.05 and $.25 per gallon as a result of the transition. And, according to the American Petroleum Institute, the domestic refining industry has invested over $8 Billion to comply with the new regulations.
ULSD will run in any engine designed for the ASTM D-975 diesel fuels.
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It is, however, known to cause some seals to shrink (Source: Chevron paper) and may cause fuel pump failures in Volkswagen TDI engines used in pre-2009 models. TDI engines from 2009 and on are designed to use ULSD exclusively; biodiesel blends are reported to prevent that failure (Source:
HRCCC.org Biodiesel Best Management Practices).
