Lubricated part having partial hard coating allowing reduced amounts of antiwear additive

Abstract

A lubricated part composition containing (a) a part with at least a partial hard surface coating of average thickness less than about 25 micrometres, said coating containing at least one moiety selected from the group consisting of silicides, nitrides, carbides, borides, oxides, sulphides and mixtures thereof; (b) a detergent selected from at least one of the group consisting of a phenate salt, a sulphonate salt, a salixarate salt and mixtures thereof; and (c) an oil of lubricating viscosity. The invention further relates to the use of the composition to decrease engine wear, decrease sludge formation, filter plugging, decrease sulphur emissions and decrease phosphorus emissions.

Description

FIELD OF INVENTION [0001] The present invention relates to a lubricated engine part composition with a partial hard surface coating of average thickness in combination with detergents and an oil of lubricating viscosity. The composition has improved antiwear performance and / or decreased filter plugging. BACKGROUND OF THE INVENTION [0002] It is well known for lubricating oils to contain a number of additives used to protect the engine from wear, the accumulation of sludge and filter plugging. Common additives for engine lubricating oils are zinc alkyldithiophosphate (ZDDP) an antiwear additive, and overbased calcium sulphonate detergents. It is believed that ZDDP antiwear additives protect the engine by forming a protective film on metal surfaces. Typical treatment quantities of ZDDP range from 1 to 2 weight percent based on the total weight of the lubricant. Detergents such as overbased calcium sulphonate help keep the engine parts clean of soot and other deposits, and offer an alka...

AI Technical Summary

Benefits of technology

The present invention provides a lubricated part with a hard surface coating that contains various moieties such as silicides, nitrides, carbides, borides, oxides, sulphides, and mixtures thereof. The lubricated part also includes a detergent such as a phenate salt, sulphonate salt, salixarate salt, or mixtures thereof, and an oil of lubricating viscosity. The lubricated part has improved properties such as decreased wear, filter plugging, sludge formation, phosphorus emissions, sulphur emissions, sulphated ash formation, and mixtures thereof. The invention also provides a method for lubricating a part with the lubricated part.

Problems solved by technology

Further, sulphur and phosphorus tend to poison the NOx catalysts used in catalytic converters, resulting in a reduction in performance of said catalysts.

Any reduction in the performance of catalytic converters tends to result in increased amounts of greenhouse gases such as nitric oxide and / or sulphur oxides.

However, reducing the amount phosphates and sulphonates by decreasing the amount of ZDDP and / or calcium sulphonate detergents will increase the amount of wear in an engine especially on engine parts with high loading for instance in the valve train and increase the amount of sludge formed.

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