The tribological behavior of alkyl ethers and alcohols in low sulfur automotive diesel

This paper presents the impact of alkyl ethers and alcohols on the lubricity of automotive diesel. Seven ethers and five alcohols were used as lubricating additives on two low sulfur diesel fuels, at the concentration range of 50–2000 ppm. Tribological experiments carried out on the high frequency reciprocating rig showed that six of seven ethers used provide satisfactory mean wear scar diameter (WS 1.4) of less than 0.46 mm, at the concentration levels of 750–1500 ppm. Among the ethers of the same molecular type, those having the oxygen in the middle of the molecule appeared to have marginally better lubrication performance for some concentration ranges. In the case of alcohols, the effective concentration was 750 ppm or higher. Overall, alcohols appear to be better lubricants than ethers at high concentrations, maybe due to their more pronounced polar nature.