Laboratory screening tests for low sulphur diesel fuel lubricity

Abstract

AbstractSince the beginning of October 1993, environmental legislation in the USA has required the sulphur content of diesel fuel to be reduced to less than 0.05 wt.% for road vehicles. Pressure for such reductions to be adopted in other markets is growing: notably, sulphur levels as low as 10 ppm are being encouraged in Sweden by the use of tax incentives. However, it is suspected that fuel pumps suffer from lubrication problems with the use of low sulphur diesel (LSD). Additive treatment of fuels and fuel blending is thought to mitigate such problems but there is a need for an industrial method of screening candidate fuel treatments prior to expensive service or rig trials.This paper outlines a test procedure based on the Plint TE‐77 reciprocating test rig. Initial investigations have enabled fuels of known pump performance to be ranked correctly through an assessment of scuffing wear. In this test, scuffing is evaluated by surface profilometry of the flat specimen and the mechanism is verified by the detection of ‘white’ etching layers on surfaces. The test also allows the separate evaluation of mild wear by measurement of the width of the scar generated on the roller by the line contact configuration.