Engine oil compositions

Abstract

A low phosphorous or phosphorous-free sulfur lubricating oil composition and/or low phosphorous or phosphorous-free and low sulfur or sulfur-free lubricating oil composition for internal combustion engines comprising (a) a major amount of a base oil of lubricating viscosity and (b) a minor deposit-inhibiting effective amount of at least one polyol ester of the general formula wherein R 1 , R 2 and R 3 are independently aliphatic hydrocarbyl moieties having from 4 to about 24 carbon atoms, R 4 is hydrogen or an aliphatic hydrocarbyl moiety having 1 to 10 carbon atoms and x, y and z are the same or different and are integers from 1 to 6, and additive compositions and additive packages containing the foregoing polyol ester are provided.

1 . A low phosphorous or phosphorous-free lubricating oil composition comprising (a) a major amount of base oil of lubricating viscosity and (b) a minor deposit-inhibiting effective amount of at least one polyol ester of the general formula  
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2  and R 3  are independently an aliphatic hydrocarbyl moiety have from 4 to 24 carbon atoms, R 4  is hydrogen or an aliphatic hydrocarbyl moiety having 1 to 10 carbon atoms and x, y and z are the same or different and are integers from 1 to 6; 
 wherein the composition has a phosphorous content not exceeding 0.08 by weight, based on the total weight of the composition.  
 
     
     
         2 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein the base oil of lubricating viscosity is comprised of a mineral base oil.  
     
     
         3 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein the base oil of lubricating viscosity is comprised of a polyalphaolefin base oil.  
     
     
         4 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein R 1 , R 2  and R 3  of the polyol ester are independently selected from a saturated or unsaturated aliphatic hydrocarbyl moiety having from 6 to 10 carbon atoms.  
     
     
         5 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein R 1 , R 2  and R 3  are independently selected from a saturated or unsaturated aliphatic moiety having from 6 to 10 carbon atoms, R 4  is an aliphatic hydrocarbyl moiety having 1 to 6 carbon atoms and x, y and z are 1.  
     
     
         6 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein the minor deposit-inhibiting effective amount of the polyol ester is about 0.5 wt. % to about 10 wt. %, based on the total weight of the composition.  
     
     
         7 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein the minor deposit-inhibiting effective amount of the polyol ester is about 1 wt. % to about 5 wt. %, based on the total weight of the composition.  
     
     
         8 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 5 , wherein the minor deposit-inhibiting effective amount of the polyol ester is about 0.5 wt. % to about 10 wt. %, based on the total weight of the composition.  
     
     
         9 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , wherein the composition has an SAE Viscosity Grade of 0 W, 0 W-20, 0 W-30, 0 W-40, 0 W-50, 0 W-60, 5 W, 5 W-20, 5 W-30, 5 W-40, 5 W-50, 5 W-60, 10 W, 10 W-20, 10 W-30, 10 W-40, 10-50, 15 W, 15 W-20, 15 W-30 or 15 W-40.  
     
     
         10 . The low phosphorous or phosphorous-free 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.  
     
     
         11 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , having a phosphorous content not exceeding 0.05 wt. %, based on the total weight of the composition.  
     
     
         12 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 5 , having a phosphorous content not exceeding 0.05 wt. %, based on the total weight of the composition.  
     
     
         13 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 1 , having a sulfur content not exceeding 0.2 wt. %, based on the total weight of the composition.  
     
     
         14 . The low phosphorous or phosphorous-free lubricating oil composition of  claim 12 , having a sulfur content not exceeding 0.2 wt. %, based on the total weight of the composition.  
     
     
         15 . A method of operating an internal combustion engine comprising the step of operating the internal combustion engine with a low-phosphorous or phosphorous-free lubricating oil composition comprising (a) a major amount of a base oil of lubricating viscosity and (b) a minor deposit-inhibiting effective amount of at least one polyol ester of the general formula  
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2  and R 3  are independently an aliphatic hydrocarbyl moiety have from 4 to 24 carbon atoms, R 4  is hydrogen or an aliphatic hydrocarbyl moiety having 1 to 10 carbon atoms and x, y and z are the same or different and are integers from 1 to 6; 
 wherein the composition has a phosphorous content not exceeding 0.08 by weight, based on the total weight of the composition.  
 
     
     
         16 . The method of  claim 15 , wherein the base oil of lubricating viscosity is comprised of a mineral base oil.  
     
     
         17 . The method of  claim 15 , wherein the base oil of lubricating viscosity is comprised of a polyalphaolefin base oil.  
     
     
         18 . The method of  claim 15 , wherein R 1 , R 2  and R 3  of the polyol ester are independently selected from a saturated or unsaturated aliphatic hydrocarbyl moiety having from 6 to 10 carbon atoms.  
     
     
         19 . The method of  claim 15 , wherein R 1 , R 2  and R 3  are independently selected from a saturated or unsaturated aliphatic moiety having from 6 to 10 carbon atoms, R 4  is an aliphatic hydrocarbyl moiety having 1 to 6 carbon atoms and x, y and z are 1.  
     
     
         20 . The method of  claim 15 , wherein the minor deposit-inhibiting effective amount of the polyol ester is about 0.5 wt. % to about 10 wt. %, based on the total weight of the composition.  
     
     
         21 . The method of  claim 15 , wherein the minor deposit-inhibiting effective amount of the polyol ester is about 1 wt. % to about 5 wt. %, based on the total weight of the composition.  
     
     
         22 . The method of  claim 19 , wherein the minor deposit-inhibiting effective amount of the polyol ester is about 0.5 wt. % to about 10 wt. %, based on the total weight of the composition.  
     
     
         23 . The method of  claim 15 , wherein the composition has an SAE Viscosity Grade of 0 W, 0 W-20, 0 W-30, 0 W-40, 0 W-50, 0 W-60, 5 W, 5 W-20, 5 W-30, 5 W-40, 5 W-50, 5 W-60, 10 W, 10 W-20, 10 W-30, 10 W-40, 10 W-50, 15 W, 15 W-20, 15 W-30 or 15 W-40.  
     
     
         24 . The method of  claim 15 , 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.  
     
     
         25 . The method of  claim 15 , wherein the composition has a phosphorous content not exceeding 0.05 wt. %, based on the total weight of the composition.  
     
     
         26 . The method of  claim 19 , wherein the composition has a phosphorous content not exceeding 0.05 wt. %, based on the total weight of the composition.  
     
     
         27 . The method of  claim 15 , wherein the composition has a sulfur content not exceeding 0.2 wt. %, based on the total weight of the composition.  
     
     
         28 . The method of  claim 26 , wherein the composition has a sulfur content not exceeding 0.2 wt. %, based on the total weight of the composition.