Engine lubricant trends since 1990

A review is undertaken of the important trends in engine lubricant performance tests that have taken place over the last 10-15 years. Lubricant formulations are driven by industry standard specifications, original equipment manufacturer requirements, and consumer needs. A review is given of the important specifications and associated performance tests, and how these have impacted on lubricant development. The key trends are, firstly, the need for improved fuel economy, secondly, the need for improved oxidation stability, thirdly, the need for improved handling of contaminants (e.g. soot), and, fourthly, the recent move to lubricants containing low levels Of Sulphur, phosphorus, and sulphated ash, for after-treatment device compatibility reasons.