Diesel Fuel Standards

Are they helping... or just blowing smoke?

Published in the April 2009 Issue April 2010 News

If you're finding it difficult to stay current with what's going on with diesel fuel, you're probably not alone. Although most diesel pickup drivers choose to avoid environmental politics, you may be curious about the labels stuck to diesel pumps at convenience stations around the country.

In the past two decades, there have been numerous changes to fuel standards used in automobiles. And with the adaptation of new standards comes the need for implementation of new technologies for diesel engines.

The most recent changes involve ultra-low sulfur diesel (ULSD)-a term used to describe a standard for defining diesel fuel.

In an effort for the Environmental Protection Agency to adopt diesel emissions standards designed to drastically reduce the sulfur content and thus improve air quality (and to keep pace with the European Union's standards for fuel), transition to ULSD is very similar to what occurred when gas engines made the change to unleaded fuel and catalytic converters.

Thus, the switch to ULSD fuel has required the auto industry to design advanced emissions control systems that can eliminate about 90 percent of soot and nitrogen oxides from being released through the exhaust.

Dirty Engines

It is considered by many that diesel engines are possibly the dirtiest of all motor transportation fuels when it comes to releasing pollutants into the atmosphere. The most common types of pollutants being measured are: nitrogen oxides, hydrocarbons, carbon monoxide and particulate matter (exhaust smoke).

By switching to ULSD fuel, the EPA hopes to lower sulfur content while adapting to newer emissions control technologies, which reduce the amount of particulate matter from diesel emissions released into the atmosphere.

In 2006, the European Union adapted a standard (Euro IV) that allows a maximum of 50 ppm of sulfur (although Russia is still allowing 2,000-5,000 ppm in its diesel fuels). The United States adapted similar standards in 2007. It should be noted that some states, such as California, imposed the standards sooner than others. U.S. refineries were required to produce 80 percent of their diesel fuels at ULDS standards by June, 2006.

Vehicles with diesel engines built since 2007 require ULSD fuel to operate properly. However, with the exception of California (which has required ULSD fuels since 2006), retail outlets have until Dec. 1, 2010 to make the complete change. That means you need to be aware of labeling of fuels at the pump.

Does this clear things up for you? Probably not.

An Eye On Europe

The EPA tends to watch closely what's happening in Europe. And Europe (again with the exception of Russia) is adopting "Euro V" standards, which allows only 10 ppm to be released. This will be phased in by 2009. The United States will adopt those standards in 2010. (Some states will likely impose those standards sooner.) Canada standards will be slightly less stringent. South American countries are a little bit farther behind.

Basically, the Euro V standards focus on nitrogen oxides, which contribute to smog and acid rain. There are some exceptions allowed . and some countries are tying in tax incentives to encourage a faster adaptation of the standards.

Again, what does this mean?

Naturally the auto industry would like to see a consistency in standards, not only from state to state, but country to country. It's nice to have standardized fuel when designing new technologies.

ULSD makes the fuel compatible with advanced emissions systems. Diesel fuel with higher sulfur content-LSD with 500 ppm-would gum-up the advanced systems.

The Effect On Older Engines

One problem encountered with the new fuel is the effects it will have on older engines.

Since diesel engines are built for brute strength and durability (that's why they are so effective in generating enormous amounts of torque at such low rpm) the engines are quite economical and last forever. There are more than 11 million diesel engines in operation today that were built prior to the EPA's new clean diesel standards . and those vehicles could possibly continue to operate for 20-30 more years.

With ULSD (remember, that's ultra-low sulfur), although sulfur is not a lubricant, when combined with nickel content, it can increase lubricity. The reduction of sulfur means a reduction in the fuel's ability to naturally-occurring lubricity. This can lead to engine wear. It also causes a natural decrease in energy content of the fuel by about 1 percent, resulting in slightly reduced peak power and fuel economy.

Transition to ULSD will also increase the cost of diesel fuel from between 5-25 cents per gallon-not to mention the estimated $8 billion the refining industry had to invest to comply with the new regulations. And there have also been other side effects like seal shrinkage and fuel pump failures.

As far as the lubricity issues of ULSD fuels are concerned, biodiesel additives have helped create blends that can help these fuels bridge the gap with older vehicles.

Some auto manufacturers have designed exhaust features to reduce fuel consumption while eliminating the black smoke long associated with diesel engines. For example, the Mazda-CD will be released in Europe debuting a diesel particulate filter that will collect soot particles from the exhaust. It meets the Euro V standards, but not the US Tier 2 Bin 5 standards.

Manufacturers are designing very complicated/sophisticated emissions control devices-high pressure fuel systems with precise injectors, exhaust oxidation catalysts, exhaust gas recirculation features, PM filters, etc. Each must work together, yet pass individual tests. The certification process is long and cumbersome. Yet, if any one component fails, the process starts all over again, making it a costly process to introduce new technology.

The EPA has been very active to create programs to encourage emissions reduction. The EPA established the National Clean Diesel Campaign, which had an operating budget of $49.2 million in 2008, providing grants and incentives for states, businesses and individuals to promote cost-effective emission reduction strategies. But even with all this money being poured into programs to stimulate cleaner, more efficient diesel engines, the cost of the technology, along with the cost of fuel refinery, is going to be felt by lightweight diesel truck owners for years to come.

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