Lubricating oil composition for internal combustion engine

Abstract

Provided is a lubricating oil composition for internal combustion engine, which further reduces the friction to exhibit excellent fuel efficiency performance. A lubricating oil composition for internal combustion engine, which contains (A) a lubricant base oil having a dynamic viscosity of 2.0 to mm2 / s at 100° C., (B) a molybdenum-based friction modifier in an amount of 0.005 to 0.2% by mass, in terms of a molybdenum content, based on the mass of the composition, (C) a salicylate-based metal detergent in an amount of 0.01 to 1% by mass, in terms of a metal content, based on the mass of the composition, and (D) at least one compound selected from amino acids having an alkyl group, alkenyl group, or acyl group having 15 to 24 carbon atoms and / or derivatives thereof in an amount of 0.01 to 10% by mass.

Description

TECHNICAL FIELD[0001]The present invention relates to a lubricating oil composition for internal combustion engine, which has improved fuel efficiency.BACKGROUND ART[0002]Since the oil crisis, automobiles have been improved in fuel efficiency, and, from the viewpoint of protecting the resources and the environment, the improvement of fuel efficiency is still one of the important tasks for automobiles, and is increasingly needed recently. The improvement of the fuel efficiency of automobiles has been made by reducing the car body weight, improving the combustion of the engine, and reducing the friction of the engine or driving system. A method for reducing the friction of the engine includes an improvement of the valve system mechanism, a reduction of surface roughness of the sliding member, and the use of a lubricating oil composition for internal combustion engine (engine oil) having an improved fuel efficiency.[0003]Among these methods, the use of an engine oil having an improved ...

AI Technical Summary

Benefits of technology

The present patent describes a type of lubricating oil for engines that reduces friction and improves fuel efficiency. This oil composition has been found to have these beneficial effects.

Problems solved by technology

However, the molybdenum-based friction modifier has problems in that it has a limitation of the friction reducing effect even when the amount of the molybdenum-based friction modifier incorporated is increased, and in that the molybdenum-based friction modifier forms precipitate in the oil to cause the oil to be unstable.

Further, even when using the molybdenum-based friction modifier and an ester-based or amine-based ash-free friction modifier in combination, almost no further improvement of the friction reducing effect has been recognized.

In addition, recently, the lubricating oil is required to have much higher fuel efficiency, and conventional engine oils have not yet achieved satisfactory fuel efficiency.

However, not only the incorporation of such an ash-free friction modifier into a lubricating oil composition for internal combustion engine but also a synergy in the reduction of friction obtained from the ash-free friction modifier and a molybdenum-based friction modifier used in combination have not been known, and those skilled in the art have not been able to expect such an effect.

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