Additives and lubricant formulations for improved phosphorus retention properties

Abstract

A method and compositions for lubricating surfaces with lubricating oils exhibiting increased phosphorous retention. The lubricated surface includes a lubricant composition containing a base oil of lubricating viscosity, an amount of a phosphorus-containing compound and an amount of at least one hydrocarbon soluble titanium compound effective to provide an increase in phosphorus retention of the lubricant composition greater than an increase in phosphorus retention of the lubricant composition devoid of the hydrocarbon soluble titanium compound.

Description

TECHNICAL FIELD[0001]The embodiments described herein relate to particular oil soluble metal additives and use of such metal additives in lubricating oil formulations, and in particular to soluble titanium additives used to improve phosphorus retention properties of lubricant formulations that may be effective to reduce exhaust catalyst deactivation.BACKGROUND AND SUMMARY[0002]For over fifty (50) years automotive engine oils have been formulated with zinc dialkyl dithiophosphate (ZDDP) resulting in low levels of wear, oxidation, and corrosion. The additive is truly ubiquitous and found in nearly every modern engine oil. ZDDP imparts multifunctional performance in the areas of anti-wear, anti-oxidation, and anti-corrosion and is undeniably one of the most cost-effective additives in general use by engine oil manufacturers and marketers.[0003]However, there is concern that phosphorus from engine oils may volatilize and pass through the combustion chamber so that elemental phosphorus i...

AI Technical Summary

Benefits of technology

[0002]For over fifty (50) years automotive engine oils have been formulated with zinc dialkyl dithiophosphate (ZDDP) resulting in low levels of wear, oxidation, and corrosion. The additive is truly ubiquitous and found in nearly every modern engine oil. ZDDP imparts multifunctional performance in the areas of anti-wear, anti-oxidation, and anti-corrosion and is undeniably one of the most cost-effective additives in general use by engine oil manufacturers and marketers.

[0003]However, there is concern that phosphorus from engine oils may volatilize and pass through the combustion chamber so that elemental phosphorus is deposited on catalytic systems resulting in a loss of catalyst efficiency. ZDDP is known to provide a source of phosphorus that may cause significant problems with exhaust catalytic converters and oxygen sensors when the phosphorus from combusted oil forms an impermeable glaze that may mask precious metal catalytic sites. As a result there is pressure by the automakers to control and / or reduce the amount of phosphorus-containing compounds used in engine oils to facilitate longer converter and oxygen sensor life, and to reduce the manufacturer's initial costs of converters through lower precious metal content.

[0004]While a reduction in the phosphorus content of the lubricating oils may improve catalytic converter life or efficiency, the benefits of phosphorus additives for friction control and wear protection may not be conveniently matched by non-phosphorus containing additives. Accordingly, there is a competing need for additives and methods that enable protection of catalytic activity without significantly reducing a total phosphorus content of the lubricating oil compositions.

[0008]A further embodiment of the disclosure provides a method of increasing phosphorus retention in engine lubricant compositions during operation of an engine, wherein the phosphorus retention is sufficient to reduce catalyst poisoning. The method includes contacting the engine parts with a lubricant composition containing a base oil of lubricating viscosity, at least one phosphorus-containing compound, and an amount of a hydrocarbon soluble titanium compound effective to provide an increase in phosphorus retention of the lubricant composition greater than an increase in phosphorus retention of the lubricant composition devoid of the hydrocarbon soluble titanium compound.

[0009]As set forth briefly above, embodiments of the disclosure provide a hydrocarbon soluble titanium additive that may significantly improve phosphorus retention in a lubricating oil thereby reducing catalyst poisoning effects of phosphorus on catalytic converters. The additive may be mixed with an oleaginous fluid that is applied to a surface between moving parts. In other applications, the additive may be provided in a fully formulated lubricant composition. The additive is particularly directed to meeting the currently proposed GF-5 standards for passenger car motor oils and PC-10 standards for heavy duty diesel engine oil as well as future passenger car and diesel engine oil specifications. The additive may be particularly useful to enable vehicles to meet the stringent Tier-II, BIN2 120,000 mile catalyst efficiency standard.

Problems solved by technology

For over fifty (50) years automotive engine oils have been formulated with zinc dialkyl dithiophosphate (ZDDP) resulting in low levels of wear, oxidation, and corrosion.

However, there is concern that phosphorus from engine oils may volatilize and pass through the combustion chamber so that elemental phosphorus is deposited on catalytic systems resulting in a loss of catalyst efficiency.

ZDDP is known to provide a source of phosphorus that may cause significant problems with exhaust catalytic converters and oxygen sensors when the phosphorus from combusted oil forms an impermeable glaze that may mask precious metal catalytic sites.

While a reduction in the phosphorus content of the lubricating oils may improve catalytic converter life or efficiency, the benefits of phosphorus additives for friction control and wear protection may not be conveniently matched by non-phosphorus containing additives.

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