Near-frictionless Carbon Coatings for Use in Fuel Injectors and Pump Systems Operating with Low-sulfur Diesel Fuels

While sulfir in diesel fuels helps reduce friction and prevents wear and galling in fuel pump and injector systems, it also creates environmental pollution in the form of hazardous particulate and S02 emissions. The environmental concern is the driving force behind industry’s efforts to come up with new alternative approaches to this problem. One such approach is to replace sulfur in diesel fuels with other chemicals that would maintain the antifi-iction and antiwear properties provided by sulfur in diesel fuels while at the same time reducing particulate emissions. A second alternative might be to surface-treat fuel injection parts (i.e., nitriding, carburizing, or coating the surfaces) to reduce or eliminate failures associated with the use of low-sulfir diesel fuels. Our research explores the potential usefulness of a near-frictionless carbon (NFC) film developed at Argonne National Laboratory in alleviating the aforementioned problems. The lubricity of various diesel ftlels (i.e., high-sulfur, 500 ppm; low sulfur, 140 ppm; ultra-clean, 3 ppm; and synthetic diesel or Fischer-Tropsch, zero sulfur) were tested by using both uncoated and NFC-coated 52100 steel