SPECIAL REPORT
minals selling highway diesel had to meet the 15 ppm sulfur standard as of July 15, 2006. Retail stations and wholesale pur- chasers were required to meet the 15 ppm sulfur standard by Sept. 1, 2006. Now it’s second nature to fill up without
having to worry about diesel fuel sulfur content. After Dec. 1, 2014, all highway, off-road, locomotive and marine diesel fuel produced and imported will be ULSD.
USING ULSD IN OLDER VEHICLES ULSD is fully compatible with 2006 and
older vehicles. In some cases components may be affected or cause deposits in fuel tanks to break free. A good maintenance practice with older vehicles is to moni- tor diesel-powered units for possible fuel system leaks or premature fuel filter re- striction during the change over to ULSD. Under normal operating conditions
there should not be any noticeable re- duction in horsepower, but a slight drop in fuel economy could occur because the process that removes sulfur can reduce the energy content of the fuel. “Lubricity standards were introduced in 2007 to petroleum producers, which aid in better controlling the quality and properties of available diesel fuel,” said Liz Lehmann, a spokesperson for Cummins Inc. “Several school bus fleets operate on biodiesel, which inherently has higher lubricity. Cummins engines meeting EPA 2002 or later emission regulations are ap- proved for the use of B20 biodiesel.”
THE RELATIONSHIP BETWEEN ULSD AND LOW-ASH ENGINE OIL Another related product to aid in clean
air emissions is low-ash-diesel engine oil with CJ-4 specifications, which addresses the unique needs of these new engines and protects older engines. It also enhanc- es the life of the emission control system as required for regulatory compliance. Diesel engines with model years 2007
and newer will not tolerate engine oil without the low-ash specification, which prevents build up in the DPF and extends service intervals. CJ-4 benefits all diesel engines with prolonged injector life, ad- vanced soot control, internal component wear protection and piston cleanliness. Take caution not to use CJ-4 with Low
Sulfur Diesel (500 ppm) as this causes cor- rosion of internal engine parts. Our fleet at School District No. 73 in
Kamloops, British Columbia, has sev- eral older diesel engines dating back to 1997, and we’ve experienced no nega- tive impact from the transition to ULSD and low-ash engine oil. Tis change was monitored closely using the oil analysis program we have in place. Between 2007 and 2010, the EPA backed
off on automotive diesel manufacturers to help them with the transition to tougher emission standards. But school bus fleets also have varying numbers of support vehi- cles that run on automotive diesel engines. Tey do not have the same emission equip- ment as highway vehicles but can still safely run on ULSD and CJ-4 rated engine oil.
WHAT ABOUT AFTERMARKET DIESEL FUEL ADDITIVES? Since lubricity and corrosion inhibitors
are lost during the refining process, refiners add the proper amount of additives prior to retail sale. ULSD is expected to perform as well as the previous Low Sulfur Diesel. Aftermarket additives are promoted to improve fuel quality even further and have to be routinely added to the individual ve- hicle fuel tank or the fleet fuel storage tank. Tis begs the question: are aftermarket
fuel additives necessary? “Many aftermarket suppliers state that
Ultra Low Sulfur Fuel has poor lubricity, hence one needs to use an aftermarket ad- ditive to restore lubricity,” added Heather DeBaun, senior project engineer at Navi- star. “Tis is not the case. Lubricity of ultra-low sulfur fuel is a standard require- ment since 2005, and it is provided by refinery additizing (for fuels not shipped through a pipeline) or by terminal ad- ditizing (for fuels shipped via pipeline). Te lubricity of the real fuel in the market is even better than the standard requires.”
MAINTAINING DIESEL FUEL STORAGE TANKS, FUEL FILTERS Te biggest fear many fleet operators
have is excessive water in their bulk- fuel storage tank. Tis would have a catastrophic effect on every diesel engine in the fleet as a heavy price would be paid with failed fuel injection systems.
36 School Transportation News Magazine March 2011 Special gauging pastes are available that
indicate the presence of water in the fuel. Apply it to the storage tank dipstick and see if it changes color, most commonly to bright pink. Te color change is the tell- tale sign you have water in the fuel. “We
don’t honestly know enough
about what’s happening,” said Lorri Grain- awi, director of technical services at Steel Tank Institute in Lake Zurich, Ill. “We do know that there have been sporadic in- cidents
of corrosion on components
within UST (underground storage tank) systems storing ULSD. Tese incidents go back to when ULSD was first introduced. Components have failed inside tanks and dispensers in all regions of the U.S. and there have been reports in Canada. “Te best advice right now is to keep
your storage systems as clean as possible. No corrosion will take place without water.” Additional preventative maintenance on
the bus may also be necessary. “Even though ULSD has become an in-
dustry standard, fuel quality can vary. So it is important that filters are changed regu- larly,” said Mike Stotler, service education manager at Tomas Built Buses. “Today’s en- hanced fuel filters remove a greater number of impurities than they used to and can help compensate for fuel quality issues.”
THE LONG-TERM BENEFITS OF ULSD IN SCHOOL BUSES With the EPA’s implementation of the
new fuel standards, nitrogen oxide emis- sions will be reduced by 2.6 million tons each year, and soot or particulate matter will be reduced by 110,000 tons a year. Te EPA concludes that ozone and particulate matter cause a range of health problems, especially for children, whose lungs are still developing, and the elderly. Although maintenance and fuel costs
will increase, the goal is obvious: to save the planet and clean the air we breathe. Te EPA has focused heavily on this is- sue over the last 10 years, and there is no doubt it will keep a close watch on the industry and the results of this campaign as time goes by. It’s a good idea for the in- dustry to do the same. ■
Whelan is a school bus shop foremen and blogger. Contact him at jewhelan58@gmail.
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