Lubricating oil compositions with oxidative stability in diesel engines using biodiesel fuel

Abstract

A method for improving oxidative stability of a lubricating oil in a diesel engine, in which biodiesel fuel is used with diesel fuel in the diesel engine, by using as the lubricating oil a formulated oil. The formulated oil has a composition including at least one Group V lubricating oil base stock. The at least one Group V lubricating oil base stock is present in an amount from 1 to 75 weight percent, based on the total weight of the lubricating oil. Oxidative stability is improved in a diesel engine lubricated with the lubricating oil, as compared to oxidative stability achieved in a diesel engine lubricated with a lubricating oil not having the at least one Group V lubricating oil base stock, as determined by a CEC L-109-16 Bio-Diesel Oxidation Bench test. The lubricating oils are useful as passenger vehicle engine oil (PVEO) products or commercial vehicle engine oil (CVEO) products.

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