Lubricating oil compositions
AssigneeInfineum International Limited
InventorsStephen Arrowsmith, Matthew D. Irving
Life of this patent
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Abstract
Lubricating oil compositions having a sulfated ash content of no more than 1.0 mass %, which contain a major amount of oil of lubricating viscosity, a minor amount of calcium salicylate detergent, an amount of a magnesium-based detergent providing at least 200 ppm of magnesium, and a basic, low molecular weight, nitrogen-containing dispersant, which compositions provide improved top ring wear protection in internal combustion engines.
Claims19
A lubricating oil composition having a TBN of from about 10 to about 18 mg KOH/g, a sulfated ash content of from about 0.8 to about 1.0 mass %, and a phosphorus content of from about 700 to about 800, said lubricating oil composition comprising:
- (a) a major amount of oil of lubricating viscosity;
- (b) a minor amount of calcium salicylate detergent;
- (c) an amount of overbased magnesium detergent having, or having on average, a TBN of from about 300 to about 550 mg KOH/g, providing the lubricating oil composition with from 200 to no greater than 1250 ppm of magnesium;
- and
- (d) a low molecular weight, nitrogen-containing dispersant derived from a polymer having a number average molecular weight (Mn) of from about 400 to about 1000, having a TBN of from 40 to 100 mg KOH/g, in an amount providing said lubricating oil composition with from 5 to 25% of the total TBN and from 20 to 60% of the total amount of dispersant nitrogen;
- and
- an amount of a high molecular weight nitrogen-containing dispersant derived from an unsaturated hydrocarbon having a number average molecular weight (Mn) of at least 1100 providing the lubricating oil composition with from 0.05 to 0.20 mass % of nitrogen:
- wherein said minor amount of calcium salicylate detergent provides said lubricating oil composition with from 5 to 90% of the total TBN;
- and said amount of overbased magnesium detergent provides said lubricating oil composition with from 5 to 40% of the total TBN, and wherein said lubricating oil composition contains less than about 100 ppm of boron.
Dependencies are inferred from the claim text.