Low viscosity engine oil with superior engine wear protection

Abstract

An engine oil lubricant composition comprising a major amount of base oil and an effective amount of a zinc dialkyl dithio phosphate, a polymeric viscosity index improver and a mixture of alkaline earth metal detergents provides improved fuel efficiency while providing excellent wear in an engine.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to U.S. Provisional Application Ser. No. 61 / 502,673 filed Jun. 29, 2011, herein incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]This invention relates to a lubricant oil composition having a sulfated ash content of about 0.6 wt % and a high-temperature high-shear (HTHS) viscosity of lower than 2.9 cP at 150° C. that provides excellent engine wear protection and improved fuel efficiency and use thereof.BACKGROUND OF THE INVENTION[0003]Fuel efficiency requirements for passenger vehicles are becoming increasingly more stringent. New legislation in the United States and European Union within the past few years has set fuel economy and emissions targets not readily achievable with today's vehicle and lubricant technology. In order to improve lubricant fuel economy performance, reduction of viscosity is typically the best path; however, present day lubricant oils with a high temperature high...

AI Technical Summary

Benefits of technology

[0008]In another aspect of the invention, there is provided a method for improving fuel efficiency and wear in an engine. The method comprising adding to an engine, an engine oil lubricant composition having a sulfated ash content of about 0.8 wt % and an HTHS of about 2.9 cP at 150° C. The lubricant composition comprises a zinc dialkyl dithio phosphate, a polymeric viscosity modifier and a mixture of alkaline earth metal detergents.

Problems solved by technology

In order to improve lubricant fuel economy performance, reduction of viscosity is typically the best path; however, present day lubricant oils with a high temperature high shear (HTHS) viscosity of less than 2.9 cP at 150° C. would not be expected to be able to provide acceptable passenger vehicle diesel engine durability performance.

As this happens, the viscosity of the oil decreases which may lead to increased engine wear.

Diesel engines are more prone to filter plugging due to high sulfated ash content of the lubricant.

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