Robert L. Freerks

Alternative Fuels: Assessment of Fischer-Tropsch Fuel for Military Use in 6.5L Diesel Engine

As the U.S. Military considers fuel sources around the world and into the future, fuels produced via nonconventional means are anticipated to become increasingly available and of growing importance. One such type of fuel, a synthetic fuel, can be produced from conversion processes employing Fischer-Tropsch (F-T) synthesis and starting with natural gas, coal or biomass feed stocks. The Single Fuel Forward (SFF or single fuel in the battlefield) policy requires the use of JP-8, JP-5 or Jet A-1. Evaluations of F-T fuels, such as synthetic JP-8, in military ground vehicles, aircraft, associated equipment, and fuel storage and distribution systems is needed to assess ability to meet desired and/or required operational performance and to identify potential issues, as well as potential benefits, with the introduction and use of these fuels. Testing of a synthetic JP-5 aviation turbine fuel, produced by Syntroleum Corporation under DOD contract, in a 6.5L diesel engine used to power the High-Mobility Multipurpose Wheeled Vehicle (HMMWV), demonstrated reduced exhaust emissions when compared to a reference low sulfur D-2 fuel. Reductions of regulated pollutants were found to be 62-72% for unburned hydrocarbons (HC), 46-60% for carbon monoxide (CO), 13-15% for oxides of nitrogen (NO x ), and 52-55% for particulate matter (PM). Pump stand wear tests, conducted using the Stanadyne Artic Rotary Injection Pumps from the HMMWV, indicated poor performance without the addition of corrosion inhibitor/lubricity improver additive per MIL-PRF-25017. However, acceptable rotary pump performance was observed with the addition of MIL-PFR-25017 lubricity improver additive.