Above: Gene Ledford, a technician II in Polk County's fleet management division, does routine maintenance work on a Caterpillar backhoe. Right: Steve Bennett (left), chief mechanic, and Todd Atchison, a technician III, work in Polk County's primary fleet maintenance facility on an aerial bucket truck. Photos: Bob Stanton

Are you prepared for the next generation of emission standards? Are you prepared to transition to a new diesel fuel? Are you prepared to incorporate new diesel engine technology into your already mixed fleet of diesel engines?

Ready or not, all three are inevitable—and are interrelated aspects of major emissions and environmental changes that will impact your vehicles and equipment within a few months. Here are the facts:

  • 2007 federal emission standards for on-highway diesel engines require significant reductions in nitrous oxide and particulate matter.
  • To enable the new engine technology, fleets must transition to ultra-low-sulfur diesel (ULSD) fuel. The fuel will available nationwide by October 2006.
  • Federal emission standards for on-highway diesel engines tighten further in 2010, requiring additional changes in vehicle engineering and engine technology.
  • In short, government fleets intending to purchase on-highway diesel-powered vehicles in 2007 and beyond must transition to ULSD and budget for higher costs for fuel, capital, and fleet operations in general. Failure to make the transition to ULSD will destroy the emissions devices being engineered for the 2007 engines, causing major and costly damage to the engines themselves.

    The transition to ULSD could be lengthy because several cycles of fuel deliveries will be required to purge residual sulfur remaining in both vehicle and bulk storage systems. Fleets should consider periodic testing of their fuel stocks as the transition progresses to assure the sulfur content is being reduced effectively.

    Fortunately, ULSD will be “backwards compatible” and can be used in pre-2007 engines with little or no change in performance. Fleets wishing to continue using current No. 2 low-sulfur diesel (LSD) must segregate their fuel stocks and take steps to prevent the entry of No. 2 LSD into vehicles equipped with post-2006 engines. By Dec. 10, 2010, the No. 2 LSD fuel we're using today will no longer be permitted for use in the United States.

    As fleets engage in this transition, they should be prepared for higher fuel prices, a reduction in miles per gallon due to ULSD's lower BTU, possible lubricity issues in older engines, and fleets in northern climates may need to address a lower tolerance to cold temperatures attendant with ULSD.

    ULSD is specifically formulated to enable new diesel engine technologies to meet the tighter 2007 federal emission standards. The new technologies are largely built upon the cooled exhaust gas emission designs recently incorporated in 2002 diesel engines. In addition to cooled exhaust gas recirculating valves, engine manufacturers will add particulate-matter filters, larger cooling systems, oxidation catalysts, and some will add variable geometry turbochargers and redesigned fuel injection technology.

    The particulate-matter filters will be a standard component on post-2006 diesel-equipped vehicles. Many of these filters will engage in automatic active regeneration where a small quantity of fuel is injected into the filter to facilitate burning of the particulate matter contained therein. This fuel injection process will heat the filter to 900° F. In many trucks, such as a fire engine, the placement of this filter will be a critical consideration in vehicle specifications. The specifier must ensure the proper placement of other frame-mounted equipment and the protection of the surfaces underneath the vehicle. The instant temperature spike created by the active regeneration process could cause material beneath a parked vehicle (like grass) to ignite, placing the vehicle in jeopardy.

    These devices will require new diagnostic monitoring and periodic servicing, all of which will require higher levels of technical training for maintenance technicians. A new diagnostic protocol (engine manufacturer diagnostics, or EMD) is being developed for this purpose and will apply to diesel-powered vehicles rated above 14,000 pounds gross vehicle weight produced after January 2007. Material extracted from the particulate-matter filters during routine servicing will likely require hazardous materials treatment and disposal. This process may be uniquely important for government fleets because their vehicles seldom generate high enough operating temperatures within their duty cycles to burn off excess particulate matter shortening service intervals for PM filtration systems.

    Because engine temperatures and air management are critical to the effectiveness of this technology, a new motor oil (PC-10) is being formulated for these engines. The new oil will be backward-compatible and usable in older engines. Due to the changes in oil formulation, fleets using extended oil drain intervals in older engines should implement oil sampling to determine the viability of the new oil in their particular operations. It's likely that oil change intervals, even in the 2007 engines, may be reduced because the additive packages may break down sooner due to the higher engine temperatures and lower tolerance for contamination.