Lubricating oil compositions with engine wear protection

Abstract

A method for improving wear control, while maintaining or improving fuel efficiency, in an engine or other mechanical component 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 a mixture as a minor component of (i) at least one metal salt of a straight chain carboxylic acid, wherein the metal is selected from the group consisting of palladium (Pd), silver (Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at least one metal salicylate salt, wherein the metal is calcium (Ca), magnesium (Mg) or combinations thereof, wherein the molar ratio of the total metal concentration from the salicylate salt divided by the total metal concentration from the straight chain carboxylic acid ranges from 0.1 to 40. The lubricating oils are useful in internal combustion engines.

1 . A method for improving wear control, while maintaining or improving fuel efficiency, in an engine or other mechanical component 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 a mixture as a minor component of (i) at least one metal salt of a straight chain carboxylic acid, wherein the metal is selected from the group consisting of palladium (Pd), silver (Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at least one metal salicylate salt, wherein the metal is calcium (Ca), magnesium (Mg) or combinations thereof, wherein the molar ratio of the total metal concentration from the salicylate salt divided by the total metal concentration from the straight chain carboxylic acid ranges from 0.1 to 40; and wherein wear control is improved and fuel efficiency is maintained or improved as compared to wear control and fuel efficiency achieved using a lubricating oil containing a minor component other than the mixture of the at least one metal salt of a straight chain carboxylic acid and the at least one metal salicylate salt. 
     
     
         2 . The method of  claim 1  wherein the lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         3 . The method of  claim 1  wherein the straight chain carboxylic acid is an aliphatic, saturated, unbranched carboxylic acid having from 8 to 26 carbon atoms, and mixtures thereof. 
     
     
         4 . The method of  claim 1  wherein the straight chain carboxylic acid is palmitic acid (C16), stearic acid (C18), or combinations thereof. 
     
     
         5 . The method of  claim 1  wherein the at least one metal salt of the straight chain carboxylic acid comprises zinc stearate, silver stearate, palladium stearate, zinc palmitate, silver palmitate, palladium palmitate, or mixtures thereof. 
     
     
         6 . The method of  claim 1  wherein the at least one metal salt of the straight chain carboxylic acid is present in an amount of from 0.01 weight percent to 5 weight percent, based on the total weight of the formulated oil. 
     
     
         7 . The method of  claim 1  wherein the at least one metal salicylate salt is present in an amount of from 0.01 weight percent to 5 weight percent, based on the total weight of the formulated oil. 
     
     
         8 . The method of  claim 1  wherein the lubricating oil base stock is present in an amount of from 70 weight percent to 95 weight percent, based on the total weight of the formulated oil. 
     
     
         9 . The method of  claim 1  wherein the formulated oil further comprises one or more of an antiwear additive, viscosity modifier, antioxidant, detergent, other dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         10 . The method of  claim 1 , wherein the at least one metal salt of the straight chain carboxylic acid comprises zinc stearate. 
     
     
         11 . The method of  claim 10 , wherein the at least one metal salicylate salt is calcium salicylate. 
     
     
         12 . The method of  claim 11 , wherein the molar ratio of the total metal concentration from the salicylate salt divided by the total metal concentration from the straight chain carboxylic acid ranges from 0.4 to 10. 
     
     
         13 . A lubricating oil having a composition comprising a lubricating oil base stock as a major component; and a mixture as a minor component of (i) at least one metal salt of a straight chain carboxylic acid, wherein the metal is selected from the group consisting of palladium (Pd), silver (Ag), gold (Au), zinc (Zn), and combinations thereof, and (ii) at least one metal salicylate salt, wherein the metal is calcium (Ca), magnesium (Mg) or combinations thereof; wherein the molar ratio of the total metal concentration from the salicylate salt divided by the total metal concentration from the straight chain carboxylic acid ranges from 0.1 to 40; and wherein wear control is improved and fuel efficiency is maintained or improved as compared to wear control and fuel efficiency achieved using a lubricating oil containing a minor component other than the mixture of the at least one metal salt of a straight chain carboxylic acid and the at least one metal salicylate salt. 
     
     
         14 . The lubricating oil of  claim 13  wherein the lubricating oil base stock comprises a Group I, Group II, Group III, Group IV or Group V base oil. 
     
     
         15 . The lubricating oil of  claim 13  wherein the straight chain carboxylic acid is an aliphatic, saturated, unbranched carboxylic acid having from 8 to 26 carbon atoms, and mixtures thereof. 
     
     
         16 . The lubricating oil of  claim 13  wherein the straight chain carboxylic acid is palmitic acid (C16), stearic acid (C18), or combinations thereof. 
     
     
         17 . The lubricating oil of  claim 13  wherein the at least one metal salt of the straight chain carboxylic acid comprises zinc stearate, silver stearate, palladium stearate, zinc palmitate, silver palmitate, palladium palmitate, and mixtures thereof. 
     
     
         18 . The lubricating oil of  claim 13  wherein the at least one metal salt of the straight chain carboxylic acid is present in an amount of from 0.01 weight percent to 5 weight percent, based on the total weight of the formulated oil. 
     
     
         19 . The lubricating oil of  claim 13  wherein the at least one metal salicylate salt is present in an amount of from 0.01 weight percent to 5 weight percent, based on the total weight of the formulated oil. 
     
     
         20 . The lubricating oil of  claim 13  wherein the lubricating oil base stock is present in an amount of from 70 weight percent to 95 weight percent, based on the total weight of the formulated oil. 
     
     
         21 . The lubricating oil of  claim 13  further comprising one or more of an antiwear additive, other viscosity modifiers, antioxidant, detergent, other dispersant, pour point depressant, corrosion inhibitor, metal deactivator, seal compatibility additive, anti-foam agent, inhibitor, and anti-rust additive. 
     
     
         22 . The lubricating oil of  claim 13 , wherein the at least one metal salt of the straight chain carboxylic acid comprises zinc stearate. 
     
     
         23 . The lubricating oil of  claim 22 , wherein the at least one metal salicylate salt is calcium salicylate. 
     
     
         24 . The lubricating oil of  claim 23 , wherein the molar ratio of the total metal concentration from the salicylate salt divided by the total metal concentration from the straight chain carboxylic acid ranges from 0.4 to 10. 
     
     
         25 . The lubricating oil of  claim 13  which is a passenger vehicle engine oil (PVEO).