Engine oil formulations for biodiesel fuels

摘要

The lubricant for an internal combustion engine fueled by a biodiesel fuel (that is, a liquid fuel containing a C1-C4 alkyl ester of a carboxylic acid of about 12 to about 24 carbon atoms) exhibits improved resistance to oxidative degradation when the lubricant contains an alkali metal detergent.

主权项

1. A method for lubricating a sump-lubricated internal combustion engine fueled by a liquid fuel which comprises a middle distillate fuel and about 2 to about 50 percent by weight of a C1-C4 alkyl ester of a carboxylic acid of about 12 to about 24 carbon atoms, comprising supplying to the sump a lubricant comprising a mineral oil of lubricating viscosity, and a minor amount of an oil-soluble overbased sodium sulfonate detergent which is present at about 0.02 to about 5 percent by weight of the lubricant composition, being in an amount to provide about 250 to about 5000 parts by million by weight of sodium to the lubricant composition.