Fleets and independents take note: experts warn that the impending switch to ultra-low-sulfur diesel (ULSD) this fall will require you to more closely monitor how the fuel behaves in your tank, as well as any fuel additives you use today.
“You need to be careful because the new diesel particulate filters [DPFs] coming out with the new engines next year are very sensitive to what passes through them—and what goes in your fuel tank can affect them,” John Taracha, product manager for diesel fuel additives for Lubrizol Corp., told FleetOwner.
“Diesel fuel itself is also changing in terms of its chemical makeup and fuel is going to experience higher levels of stress from the new engine environment than in the past,” he added. “Engines are going to be operating at much higher temperatures with increased fuel injection pressures.”
Those far more stressful operating conditions and the significant drop in sulfur content are only part of why ULSD will behave differently. “It’s not just about pulling out sulfur from the fuel, because we’re also pulling out molecules attached to the sulfur as well,” he explained. “That means ULSD is going to get a little waxier, which means it’s going to behave differently at lower temperatures.”
Refineries used to compensate for diesel’s tendency to “gel” at low temperatures by diluting it with between 25% and 50% kerosene, especially in the winter. Since kerosene is heavy in sulfur content, new low-sulfur kerosene blends are needed. The same is true for additives fleets buy to improve diesel’s cold flow performance while beefing up lubricity and anti-wear protection.
“Additives themselves need to have a 15 [parts per million] sulfur content or lower, so when you mix it with ULSD, it’s sulfur content doesn’t increase” Taracha said. “In the past, we had far more ‘leeway’ in the chemical composition of additives – more ‘headroom’ if you like – than we do heading into ’07 because engine tolerances are dramatically tighter.”
That promoted a warning from the Bethesda, MD-based Automotive Specialty Products Alliance (ASPA) to the trucking community to closely monitor the labels on diesel fuel additives to confirm whether they are approved for use in ’07 engines or not.
“Buried in the middle of the [ULSD] fuel rule was a requirement to use only low-sulfur additives in ’07 engines…additives must be properly labeled to reflect that,” Aaron Lowe, vp-government affairs for the Automotive Aftermarket Industry Assn. (AAIA), told FleetOwner.
“We don’t anticipate any labeling issues with [fuel additive] products that are going to be on the shelf this October [when ULSD goes on the market], but there’s no way to guarantee that,” he said. “That’s why we’re stressing to the trucking industry now to carefully watch what additives they are using in their fuels as we switch to ULSD.”
