Effect of Low-Lubricity Fuels on Diesel Injection Pumps - Part I: Field Performance 920823

The U.S. Department of Defense has adopted a concept in which a single fuel will be used on the battlefield; diesel fuel will be replaced by JP-8/JP-5/Jet A-1 in compression ignition engines, thereby decreasing the fuel logistics burden. JP-8 fuel has successfully undergone extensive testing in both the laboratory and in field trials. However, increased failure rates for fuel-lubricated rotary injection pump components operating on Jet A-1 aviation turbine fuel were reported during Operation Desert Shield. This paper is the first of two and describes the disassembly and failure analysis of twelve rotary fuel injection pumps that operated on Jet A-1. Also disassembled as a baseline for comparison were three additional pumps from civilian vehicles that had operated on commercial diesel. Each of the pumps had a unique service history, making quantitative comparison difficult. The results of this investigation indicate that most failures in the field may be attributed to causes other than poor fuel lubricity. Observed pump failure modes ranged from normal wear, to contamination, to catastrophic pump seizure. However, the cause of failure in three of the pumps was not evident. As a result, the possibility that low-lubricity/viscosity fuel has a deleterious effect could not be conclusively eliminated. The effects of low lubricity on pump performance under controlled laboratory conditions is evaluated in a subsequent paper.