Lubricating oil composition

Abstract

A lubricating oil composition having a sulfur content of up to about 0.4 wt. % and a sulfated ash content of up to about 0.5 wt. % as determined by ASTM D874 is disclosed which comprises (a) a major amount of an oil of lubricating viscosity; (b) at least one oil-soluble or dispersed oil-stable boron-containing compound having greater than 400 ppm of boron, based upon the total mass of the composition; and (c) at least one oil-soluble or dispersed oil-stable molybdenum-containing compound having at least about 1100 ppm of molybdenum, based upon the total mass of the composition; wherein the lubricating oil composition has a ratio of sulfur to molybdenum of less than or equal to about 4:1.

1 . A lubricating oil composition having a sulfur content of up to about 0.4 wt. % and a sulfated ash content of up to about 0.5 wt. % as determined by ASTM D874 and comprising (a) a major amount of an oil of lubricating viscosity; (b) at least one oil-soluble or dispersed oil-stable boron-containing compound having from about 400 ppm to no more than about 2000 ppm of boron of boron, based upon the total mass of the composition; and (c) at least one oil-soluble or dispersed oil-stable molybdenum-containing compound having at least about 1100 ppm of molybdenum, based upon the total mass of the composition; wherein the lubricating oil composition has a ratio of sulfur to molybdenum of about 0.5:1 to less than or equal to about 4:1. 
     
     
         2 . The lubricating oil composition of  claim 1 , wherein the oil of lubricating viscosity is comprised of a mineral base oil. 
     
     
         3 .- 5 . (canceled) 
     
     
         6 . The lubricating oil composition of  claim 1 , wherein the oil-soluble or dispersed oil-stable boron-containing compound is selected from the group consisting of borated dispersant; a borated friction modifier, a dispersed alkali metal or a mixed alkali metal or an alkaline earth metal borate, a borated epoxide, a borate ester, a borated amide, a borated sulfonate, and mixtures thereof. 
     
     
         7 .- 11 . (canceled) 
     
     
         12 . The lubricating oil composition of  claim 1 , having a ratio of sulfur to molybdenum of about 1:1 to about 2.5:1. 
     
     
         13 . The lubricating oil composition of  claim 1 , wherein the oil-soluble or dispersed oil-stable molybdenum compound is selected from the group consisting of a sulfurized or non-sulfurized molybdenum polyisobutenyl succinimide complex, molybdenum dithiocarbamate, dispersed hydrated molybdenum compound, acidic molybdenum compound or a salt thereof and mixtures thereof. 
     
     
         14 .- 16 . (canceled) 
     
     
         17 . The lubricating oil composition of  claim 1 , having at least about 700 ppm of boron and a ratio of sulfur to molybdenum of about 1:1 to about 2.5:1. 
     
     
         18 . The lubricating oil composition of  claim 1 , wherein the sulfur is derived from a compound selected from the group consisting of an alkyl or alkenyl sulfide, polyisobutyl dithiothione, ashless dithiocarbamate and mixtures thereof. 
     
     
         19 . The lubricating oil composition of  claim 1 , wherein a major amount of the sulfur is derived from a bisdithiocarbamate compound of the Formula: 
       
         
           
           
               
               
           
         
         wherein R 13 , R 14 , R 15 , and R 16  are the same or different and are aliphatic hydrocarbyl groups having 1 to 13 carbon atoms and R 17  is an alkylene group having 1 to 8 carbon atoms. 
       
     
     
         20 . (canceled) 
     
     
         21 . The lubricating oil composition of  claim 1 , wherein the oil-soluble or dispersed oil-stable boron-containing compound is a dispersed hydrated alkali-metal borate, the oil-soluble or dispersed oil-stable molybdenum compound is a sulfurized or non-sulfurized molybdenum polyisobutenyl succinimide complex, and the sulfur is derived from an ashless dithiocarbamate. 
     
     
         22 . The lubricating oil composition of  claim 1 , having a sulfated ash content of up to about 0.4 wt. % as determined by ASTM. D874. 
     
     
         23 . The lubricating oil composition of  claim 1 , which is substantially free of phosphorus. 
     
     
         24 . The lubricating oil composition of  claim 1 , which is substantially free of zinc dialkyl dithiophosphate. 
     
     
         25 . The lubricating oil composition of  claim 1 , further comprising at least one additive selected from the group consisting of metallic detergents, ashless dispersants, friction modifiers, extreme pressure agents, viscosity index improvers and pour point depressants. 
     
     
         26 . A method of operating an internal combustion engine comprising the step of operating the internal combustion engine with a lubricating oil composition having a sulfur content of up to about 0.4 wt. % and a sulfated ash content of up to about 0.5 wt. % as determined by ASTM D874 and comprising (a) a major amount of an oil of lubricating viscosity; (b) at least one oil-soluble or dispersed oil-stable boron-containing compound having from about 400 ppm to no more than about 2000 ppm of boron, based upon the total mass of the composition; and (c) at least one oil-soluble or dispersed oil-stable molybdenum-containing compound having at least about 1100 ppm of molybdenum, based upon the total mass of the composition; wherein the lubricating oil composition has a ratio of sulfur to molybdenum of about 0.5:1 to less than or equal to about 4:1. 
     
     
         27 .- 28 . (canceled) 
     
     
         29 . The method of  claim 26 , wherein the oil-soluble or dispersed oil-stable boron-containing compound is selected from the group consisting of borated dispersant; a borated friction modifier, a dispersed alkali metal or a mixed alkali metal or an alkaline earth metal borate, a borated epoxide, a borate ester, a borated amide, a borated sulfate and mixtures thereof. 
     
     
         30 .- 34 . (canceled) 
     
     
         35 . The method of  claim 26 , wherein a major amount of the sulfur is derived from a bisdithiocarbamate compound of the formula: 
       
         
           
           
               
               
           
         
         wherein R 13 , R 14 , R 15 , and R 16  are the same or different and are aliphatic hydrocarbyl groups having 1 to 13 carbon atoms and R 17  is an alkylene group having 1 to 8 carbon atoms. 
       
     
     
         36 . The method of  claim 26 , wherein the oil-soluble or dispersed oil-stable boron-containing compound is a dispersed hydrated alkali-metal borate, the oil-soluble or dispersed oil-stable molybdenum compound is a sulfurized or non-sulfurized molybdenum polyisobutenyl succinimide complex, and the sulfur is derived from an ashless dithiocarbamate. 
     
     
         37 . (canceled) 
     
     
         38 . The method of  claim 26 , wherein the lubricating oil composition is substantially free of phosphorus. 
     
     
         39 . The method of  claim 26 , wherein the lubricating oil composition is substantially free of zinc dialkyl dithiophosphate. 
     
     
         40 .- 41 . (canceled) 
     
     
         42 . An internal combustion engine lubricated with the lubricating oil composition of  claim 1 . 
     
     
         43 .- 44 . (canceled)