Engine Lubricant Trends Since 1990

Abstract

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.

Environmental life-cycle assessment (LCA) of lubricants

“…11.12, the specifi c fuel consumption reduces linearly with the decrease in lubricant HTHS viscosity from 5.0 to 3.5 mPa s. This is in accordance with similar fi ndings by Devlin et al [107]. The recommended HTHS viscosity for heavy-duty diesel engines is above 3.5 mPa s [104]. This precludes the use of SAE 0W-20 lubricants for that purpose.…”

“…Standardised dynamometer tests, which refl ect driving conditions more accurately, provide more realistic values than bench tests, which cannot reproduce all operating conditions. The requirement for fuel economy leads to the use of low-viscosity oils with friction modifi er additives to protect the engine cylinder surface against wear [104]. According to original equipment manufactures (OEMs), HTHS values must not be lower than 2.6 mPa s to guarantee safe engine operation.…”

Revisión Del Proceso De La Degradación en Los Aceites Lubricantes en Motores De Gas Natural Comprimido Y Diesel

“…Este parámetro es el llamado Factor de Stress del Aceite (OSF: Oil Stress Factor). Este parámetro ha sido utilizado como estimador del potencial estrés que sufre el aceite y permite cierta correlación con su posible degradación como consecuencia del diseño del motor 4,7,8 . El OSF considera la relación existente entre la potencia específica por cilindrada, el periodo de servicio de aceite y el volumen de cárter, como se muestra en la ecuación siguiente.…”

In-Cylinder Fuel and Lubricant Effects on Gasoline Engine Friction

“…The main trend in engine lubricants over the last 10 -15 years have required formulations to have better antioxidant performance, giving them longer service lives, better dispersant -detergent performance to help maintain cleanliness and efficiency of engines, have better compatibility with after treatment devices and to give a vehicle improved fuel economy performance (Taylor, Mainwaring et al 2005). There is a direct correlation between furthering fuel economy and reducing hydrocarbon consumption and the emission of C02.…”