Fuel economy additive and lubricant composition containing same
AssigneeExxon Chemical Patents Inc.
InventorCharles Herbert Bovington
Life of this patent
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Abstract
A lubricant composition capable of improving the fuel economy of an internal combustion engine and comprising a base oil as a major component and from about 2 to about 15 wt. %, based on the weight of composition, of a fuel economy improving additive having a viscosity greater than the viscosity of the bulk lubricant and being selected such that the lubricant is characterized by (1) a positive deviation from that of a theoretical line when the elastohydrodynamic (EHD) film thickness thereof is plotted against entrainment speed on a log basis, and by (2) a traction coefficient under both hydrodynamic and mixed lubrication conditions which is lower than it would have been if the fuel economy improving additive were not present in the lubricant is disclosed.
Claims14
A crankcase lubricant composition capable of improving the fuel economy of an internal combustion engine lubricated therewith, which comprises:
- a base oil of lubricating viscosity as a major component;
- and from about 2 to about 50 wt. %, based on the weight of composition, of a fuel economy improving additive;
- said fuel economy improving additive comprising a polar compound selected from the group consisting of full and partial esters of polyhydric alcohols and unsaturated aliphatic carboxylic acids having from about 9 to about 36 carbon atoms in the carbon chain and having a viscosity greater than the viscosity of said base oil;
- and said fuel economy improving additive being selected such that the lubricant composition is characterized by a traction coefficient under both hydrodynamic and mixed lubricant conditions which is lower than it would have been if said fuel economy improving additive were not present in the lubricant composition.
A method for improving the fuel economy of an internal combustion engine, which comprises:
- adding to the crankcase of an engine to be operated under improved fuel economy conditions, a crankcase lubricant composition comprising a base oil of a lubricating viscosity as a major component, and from about 2 to about 50 wt. % based on the weight of composition, of a fuel economy improving additive;
- said fuel economy improving additive comprising a polar compound selected from the group consisting of full and partial esters of polyhydric alcohols and unsaturated aliphatic carboxylic acids having from about 9 to about 36 carbon atoms in the carbon chain having a viscosity greater than the viscosity of said base oil;
- and said fuel economy improving additive being selected such that the lubricant composition is characterized by a traction coefficient under both hydrodynamic and mixed lubricant conditions which is lower than it would have been if said fuel economy improving additive were not present in the lubricant composition.
Dependencies are inferred from the claim text.