The Development of a “Pin-on-Twin” Scuffing Test to Evaluate Materials for Heavy-Duty Diesel Fuel Injectors

Abstract

In order to meet stricter emissions requirements, advanced heavy-duty diesel fuel injection systems will be required to operate at higher pressures and temperatures and in fuels that have poorer lubricity. Scuffing, as a mode of failure, severely limits injector life, and new materials and processes are required to resist scuffing in these more stringent operating conditions. Consequently, there is a need to test the ability of candidate fuel system materials to resist scuffing in fuel-lubricated environments. This paper describes a pin-on-twin reciprocating wear test in which a cylindrical specimen slides, under load, across two fixed, parallel cylindrical specimens that are perpendicular to the axis of the upper sliding specimen. Cylinders of annealed AISI 52100 were tested dry and lubricated by Jet A fuel and on-highway #2 diesel fuel. The friction force was found to give a reliable real-time determination of the onset of scuffing as verified by the morphology of the wear scar. The scar width and surface roughness profiles either did not reliably detect the onset or were difficult to carry out with this geometry.

*Research sponsored by the U.S. Department of Energy, Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Office of Freedom CAR and Heavy Vehicle Technologies, under contract DE-AC05-00OR22725 with UT-Battelle LLC.

Review led by Roger Melley

KEY WORDS:

• Bench Tests
• Scuffing
• Fuel Injectors
• Surface Roughness
• Friction
• Diesel Engines
• Diesel Fuels
• Fuel Lubricity
• Steel

ACKNOWLEDGEMENTS

Research sponsored by the U.S. Department of Energy, Assistant Secretary for Energy Efficiency and Renewable Energy, Office of FreedomCAR and Heavy Vehicle Technologies, under contract DE-AC05-00OR22725 with UT-Battelle LLC. J. Qu was supported in part by an appointment to the ORNL Postdoctoral Research Associates Program administered jointly by ORNL and ORISE.

Notes

*Research sponsored by the U.S. Department of Energy, Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Office of Freedom CAR and Heavy Vehicle Technologies, under contract DE-AC05-00OR22725 with UT-Battelle LLC.

Review led by Roger Melley