Development of the diesel fuel additive lubricity model

Abstract The high frequency reciprocating rig (HFRR) wear scar response of a range of different diesel fuel additives with different molecular structures and functionality is shown to be uniform between 2 and 6 × 10−3 molal concentration in contrast to a response curve based upon a mass/volume axis. The similarity of the wear scar response for the different types of additives on a molar concentration basis is analysed to show that whatever their various molecular structures, the additives have one polar group which is adsorbed onto the metal surface. The additivity of different diesel fuel additives for the HFRR wear scar diameter reduction test in a formulated mixture is explained on the basis of the summation of their molal concentrations.