July 2008, Work Truck - Feature
Tackling Diesel Fuel Stabilization & Filtration Issues
By Joe Bohn
With diverse vehicle fleets operating specialized, infrequently used trucks, avoiding diesel fuel stabilization has become more challenging.
Stablization a Problem
The City of San Diego fire-rescue operations had concerns about diesel fuel stabilization in infrequently used vehicles. The concerns centered chiefly on two Freightliner tractors and box trucks assigned to the Urban Search and Rescue Task Force.
The vehicles have large-capacity fuel tanks, including two 120-gallon tanks in the tractors and two 50-gallon tanks in the box trucks, and are typically not driven enough to completely cycle-out the fuel in a timely manner.
The Fire-Rescue fleet solved the issue by using an off-the-shelf fuel stabilizer and implementing a monthly mandatory trip requirement. "We decided to start them [infrequently used vehicles] and have an appropriately licensed individual travel north 50 miles and bring them back," said Stephen Shipkowski, former fleet superintendent for San Diego’s fire-rescue operations and now fleet maintenance supervisor for San Diego’s police department.
Solving Fuel Filtration Issues
The City of Kansas City fleet incurred increased water absorption in its fuel tanks after switching to ULSD in 2006, according to Sam Swearngin, CAFM, central fleet superintendent. The problem affected the fleet’s use of both regular and biodiesel fuels, causing freeze-ups in the winter. The remedy was to install water separators dispensers on fueling tanks at the city’s 12 fueling sites, which service 2,700 city vehicles.
Manufacturers have tightened the fuel filter microns to minute levels to help provide cleaner fuel. Many truck operators have also added a second filter to the truck framework and a third layer of filtration at the dispensing pump, according to Robin MacDonald, marketing manager for Modesto, Calif.-based Racor Division of Parker Hannifin.
Water isn’t the only fleet concern with diesel fuel. ULSD, with its tendency to act as a solvent, cleaning out or removing dirt normally found in fuel system tanks and plumbing, has also given rise to other contamination issues.
The Racor RV Series filter (RVFS) vessels, designed for use in bulk fuel storage, fuel dispensing, or fuel transfer and large engine applications, can be set up as a filter/water separator or particulate filter.
As a filter/water separator, the RV filters remove emulsified free water and solids from diesel fuel, gasoline, and other hydrocarbon streams. When equipped with filter separator elements, water can be drained and removed from the RVFS sump. Set up as a particulate filter, the RVFS is designed to remove solid contaminants, such as dirt, rust, scale, and other materials from a hydrocarbon fuel stream, down to two microns. WT