Lubricant compositions having improved low temperature performance

Abstract

Disclosed are lubricant compositions prepared with Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/ 1 RN); and a unique ratio of branched carbons to straight chain (BC/SC) carbons; a unique ratio of branched carbons to terminal carbons (BC/TC); and unique MRV behavior as a function of base stock naphthene ratio (2R+N/1RN).

1 . A lubricating composition comprising:
 a Group III base stock having at least 90 wt. % saturated hydrocarbons;   a kinematic viscosity at 100° C. (KV100) of 4.0 cSt to 12.0 cSt, a viscosity index of from 120 to 133,   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.43; and   an effective amount of one or more lubricant additives.   
     
     
         2 . The composition of  claim 1 , wherein the base stock has a KV100 of from 4.0 cSt to 5.0 cSt. 
     
     
         3 . The composition of  claim 1 , wherein the base stock has a KV100 is from 5.0 cSt to 7.0 cSt. 
     
     
         4 . The composition of  claim 2 , wherein the viscosity index is 120 to 133 and is less than or equal to 142*(1−0.0025 exp(8*(2R+N/1RN))). 
     
     
         5 . The composition of  claim 3 , wherein the viscosity index is 120 to 133 and is less than or equal to 150.07*(1−0.0106*exp(4.5*(2R+NRRN))). 
     
     
         6 . A passenger car motor oil composition comprising:
 a Group III base stock comprising:   at least 90 wt. % saturated hydrocarbons;   kinematic viscosity at 100° C. of from 4.0 cSt up to 5.0 cSt;   a viscosity index of from 120 to less than 140;   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.45; and   an effective amount of one or more lubricant additives.   
     
     
         7 . The composition of  claim 6 , wherein the viscosity index is 120 to 140 and is less than or equal to 142*(1−0.0025 exp(8*(2R+N/1RN))). 
     
     
         8 . A heavy duty diesel engine lubricating oil composition comprising:
 a Group III base stock comprising:   at least 90 wt. % saturated hydrocarbons;   kinematic viscosity at 100° C. of from 5.5 cSt up to 7.0 cSt;   a viscosity index of from 120 to less than 144;   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.56; and   an effective amount of one or more lubricant additives.   
     
     
         9 . The composition of  claim 8 , wherein the viscosity index is 120 to 144 and is less than or equal to 142*(1−0.0025 exp(8*(2R+N/1RN))). 
     
     
         10 . A lubricating composition comprising:
 a Group III base stock comprising:   at least 90 wt. % saturated hydrocarbons;   kinematic viscosity at 100° C. of 4.0 cSt to 5.0 cSt;   a viscosity index of 120 to 140;   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.52;   a ratio of branched carbons to straight chain carbons (BC/SC) less than or equal to 0.21; and   an effective amount of one or more lubricant additives.   
     
     
         11 . The lubricating composition of  claim 10 , wherein the base stock has a ratio of branched chain carbons to terminal carbons (BC/TC) less than or equal to 2.1. 
     
     
         12 . A lubricating composition comprising:
 a Group III base stock comprising:   at least 90 wt. % saturated hydrocarbons;   kinematic viscosity at 100° C. of 5.0 cSt to 12.0 cSt;   a viscosity index of 120 to 140;   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.59;   a ratio of branched carbons to straight chain carbons (BC/SC) less than or equal to 0.26; and   an effective amount of one or more lubricant additives.   
     
     
         13 . The lubricating composition of  claim 12 , wherein the base stock has a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.59 and BC/TC ≤2.3. 
     
     
         14 . A lubricating composition comprising:
 a Group III base stock comprising:   at least 90 wt. % saturated hydrocarbons;   kinematic viscosity at 100° C. (KV100) of 4.0 cSt to 5.0 cSt;   a viscosity index of from 120 to 140; and   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.45; and   an effective amount of one or more lubricant additives.   
     
     
         15 . The composition of  claim 14 , wherein the base stock KV100 of 4.0 to 4.7. 
     
     
         16 . A lubricating composition comprising:
 a Group III base stock comprising:   at least 90 wt. % saturated hydrocarbons;   kinematic viscosity at 100° C. (KV100) of 5.0 cSt to 12.0 cSt;   a viscosity index of from 120 to 144;   a ratio of multi-ring naphthenes to single ring naphthenes (2R+N/1RN) of less than 0.56; and   an effective amount of one or more lubricant additives.   
     
     
         17 . The composition of  claim 16 , wherein the base stock KV100 of 5.5 to 7.0.