A lubricating oil composition

Abstract

A lubricating oil composition comprising: (A) an oil of lubricating viscosity in a major amount, comprising a Group III base stock; (B) as an additive component in a minor amount, a viscosity index improver comprising a linear or star-shaped polymer which is derivable, at least in part, from the polymerisation of one or more conjugated diene monomers; and, wherein the lubricating oil composition is contaminated with at least 0.3 mass %, based on the total mass of the lubricating oil composition, of a biofuel or a decomposition product thereof and mixtures thereof.

Description

field of invention [0001] The present invention relates to automotive lubricating oil compositions, and more particularly to gasoline (spark ignition) and diesel (compression ignition) internal combustion engines at least partially fueled with biofuel, especially compression gas engines at least partially fueled with biodiesel fuel. Ignition internal combustion engines and spark ignition internal combustion engines fueled at least partially with bioethanol fuel, automotive lubricating oil compositions for crankcase lubrication, such compositions are referred to as crankcase lubricants. [0002] In particular, but not exclusively, the present invention relates to automotive lubricating oil compositions, preferably automotive lubricating oil compositions having low levels of phosphorus and low levels of sulfur and / or sulfated ash, which are used in biofuel-fueled exhibiting improved antioxidant performance during operation of an engine; and to the use of an additive in such comp...

AI Technical Summary

Problems solved by technology

[0007] Oxidation of lubricants often produces corrosive acids a

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