ESSO RESEARCH AND ENGINEERING CO LINDEN NJ PRODUCTS RESEARCH DIV
Ten commercial fuels in the jet fuel range have been examined for differences in physical properties, chemical composition, and frictionwear behavior. Viscosity, volatility, G. C. separations, sulfur, nitrogen and acidity are tabulated. The fuels differ markedly in their frictionwear performance. Although this seems to correlate somewhat with viscosity and possibly with hydrocarbon structure, the greatest effect appears to be due to trace components in the fuel. Acid constituents appear to be most effective. An occurrence of sticking in the fuel-control valve of operational jet engines has led to the examination of a number of commercial JP-4s from different sources. These have been found to give quite different performance in the laboratory ball-on- cylinder rig. Correlation between laboratory and field appears to be good based on the little field information available. Some of the fuels are extremely poor in lubricity. Special lubricity additives give a marked improvement in performance in laboratory tests, including the Vickers vane pump test. Corrosion inhibitors have also been found to be effective lubricity additives. The amount of additive necessary to give substantial improvement is much less than that necessary for anti-scuff performance in the Ryder gear test. As little as 50 ppm, and probably less, alters the lubricity markedly.
Quarterly progress rept. no. 3, 15 Nov 1965-15 Feb 1966