Lubricating oil compositions with engine wear protection

摘要

A method for improving wear control, while maintaining or improving deposit control and fuel efficiency, in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one dispersant and a mixture of viscosity modifiers, as minor components. The at least one dispersant is a polyalkenyl succinic derivative and at least one viscosity modifier is a vinyl aromatic-containing polymer or copolymer. A lubricating engine oil having a composition including a lubricating oil base stock as a major component, at least one dispersant and a mixture of viscosity modifiers, as minor components. The lubricating engine oils are useful in internal combustion engines including direct injection, gasoline and diesel engines.

主权项

1. A method for improving wear control, while maintaining or improving deposit control and fuel efficiency, in an engine lubricated with a lubricating oil by using as the lubricating oil a formulated oil, said formulated oil having a composition comprising a lubricating oil base stock as a major component; and at least one dispersant and a mixture of viscosity modifiers, as minor components; wherein at least one dispersant is a polyalkenyl succinic derivative and at least two viscosity modifiers, wherein the at least two viscosity modifiers include a vinyl aromatic-containing polymer or copolymer having a weight average molecular weight greater than 80,000, and a number average molecular weight greater than 40,000; wherein the vinyl aromatic-containing polymer or copolymer has an amount of vinyl aromatic content greater than 10% by weight of the vinyl aromatic-containing polymer or copolymer; and wherein wear control is improved and deposit control and fuel efficiency are maintained or improved as compared to wear control, deposit control and fuel efficiency achieved using a lubricating engine oil containing minor components other than the at least one dispersant and the mixture of viscosity modifiers, wherein at least one viscosity modifier is a linear styrene-isoprene block copolymer and at least one viscosity modifier is a bimodal styrene-isoprene star copolymer having a Mw of about 100,000 and about 1,000,000 and a Mn of about 100,000 and about 800,000, wherein the mixture of viscosity modifiers is present in an amount (total solid polymer content) of from 0.5 weight percent to 2.0 weight percent, based on the total weight of the formulated oil.