Sae 15w-30 lubricating oil composition having improved oxidative stability

Abstract

We provide a SAE 15W-30 lubricating oil, comprising: a Group II base oil having a KV at 100° C. from 5.0 to 8.0 mm 2 /s; a second Group II base oil having a KV at 100° C. from 10 to 14 mm 2 /s; a DI additive package designed to meet API CJ-4; and 0.50 to 4.95 wt % viscosity modifier; wherein the lubricating oil has a TBN from 8.55 to 11.00 and provides an Induction Time in a CMOT from 270 to 450 minutes. We also provide a process for making the lubricating oil, comprising: blending the Group II base oils to make a blended base oil mixture and adding to the blended base oil mixture: a DI additive package designed to meet API CJ-4, and a viscosity modifier; wherein the lubricating oil has a TBN from 8.55 to 11.00 and provides an Induction Time in a CMOT from 270 to 450 minutes.

It is claimed: 
     
         1 . A lubricating oil composition, comprising:
 a. a first Group II base oil having a first kinematic viscosity at 100° C. from 5.0 to 8.0 mm 2 /s;   b. a second Group II base oil having a second kinematic viscosity at 100° C. from 10 to 14 mm 2 /s;   c. a detergent inhibitor additive package designed to meet an API CJ-4 service category;   d. a TBN booster comprising 15 to 30 wt % of a diphenyl amine antioxidant, 20 to 40 wt % of an ashless non-borated dispersant, 35 to 50 wt % of an ashless borated dispersant, and 0.5 to 3 wt % of a magnesium sulfonate detergent; and   e. 0.50 to 4.95 wt % of a viscosity modifier; wherein the lubricating oil composition has a SAE 15W-30 viscosity grade by SAE J300, a TBN by ASTM D2896-11 from 8.55 to 11.00 mg KOH/g; and wherein the lubricating oil composition provides an Induction Time in a Caterpillar Micro-Oxidation Test from 270 to 450 minutes.   
     
     
         2 . (canceled) 
     
     
         3 . The lubricating oil composition of  claim 1 , wherein the first Group II base oil has a first viscosity index less than 110 and the second Group II base oil has a second viscosity index less than 110. 
     
     
         4 . The lubricating oil composition of  claim 1 , wherein the first Group II base oil has the first kinematic viscosity at 100° C. from 6.2 to 7.0. 
     
     
         5 . The lubricating oil composition of  claim 1 , wherein the second Group II base oil has the second kinematic viscosity at 100° C. from 11.0 to 13.0. 
     
     
         6 . The lubricating oil composition of  claim 3 , wherein no trim stock having a viscosity index greater than or equal to 110 is used to bring the lubricating oil composition to the 15W-30 viscosity grade. 
     
     
         7 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition comprises 0.75 to 2.25 wt % of the TBN booster. 
     
     
         8 . (canceled) 
     
     
         9 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition comprises 0.75 to 3.5 wt % of the viscosity modifier. 
     
     
         10 . The lubricating oil composition of  claim 1 , wherein the viscosity modifier is a shear stable non-dispersant olefin copolymer. 
     
     
         11 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition has a sulfated ash from 0.65 to 1.00 wt %. 
     
     
         12 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition provides 5 to 16 mg total deposits in a Moderately High Temperature Thermo-Oxidation Engine Oil Simulation Test (TEOST MHT) as determined by ASTM D7097-09. 
     
     
         13 . The lubricating oil composition of  claim 1 , wherein the lubricating oil composition provides a percent change in viscosity at 100° C. in the KRL Shear Stability Test, performed according to CEC-L-45-99, less than 20%. 
     
     
         14 . A process for making a lubricating oil composition, comprising:
 a. blending a first Group II base oil having a kinematic viscosity at 100° C. from 5.0 to 8.0 mm 2 /s with a second Group II base oil having a second kinematic viscosity at 100° C. from 10 to 14 mm 2 /s to make a blended base oil mixture having a blended base oil kinematic viscosity at 100° C. from 6.0 mm 2 /s to 7.3 mm 2 /s; and   b. adding to the blended base oil mixture:
 i. a detergent inhibitor additive package designed to meet an API CJ-4 service category; 
 ii. 0.50 to 3.50 wt % of a TBN booster comprising 15 to 30 wt % of a diphenyl amine antioxidant, 20 to 40 wt % of an ashless non-borated dispersant, 35 to 50 wt % of an ashless borated dispersant, and 0.5 to 3 wt % of a magnesium sulfonate detergent; and 
 iii. 0.5 to 4.95 wt % of a viscosity modifier to make the lubricating oil composition; wherein the lubricating oil composition has an SAE 15W-30 viscosity grade by SAE J300, a TBN from 8.55 to 11.00 mg KOH/g by ASTM D2896-11; and wherein the lubricating oil composition provides an Induction Time in a Caterpillar Micro-Oxidation Test from 270 to 450 minutes. 
   
     
     
         15 . The process of  claim 14 , wherein the first Group II base oil has a first viscosity index less than 110 and the second Group II base oil has a second viscosity index less than 110. 
     
     
         16 . The process of  claim 15 , wherein no trim stock having a viscosity index greater than or equal to 110 is blended into the blended base oil mixture or added to the blended base oil mixture. 
     
     
         17 . The process of  claim 14 , wherein the adding to the blended base oil mixture is done such that the lubricating oil composition comprises 70 to 85 wt % of the first Group II base oil and from 2.0 to 6.5 wt % of the second Group II base oil. 
     
     
         18 . (canceled) 
     
     
         19 . The process of  claim 14 , wherein the adding the TBN booster is done in an amount such that the lubricating oil composition comprises 0.75 to 2.25 wt % of the TBN booster. 
     
     
         20 . (canceled) 
     
     
         21 . The process of  claim 14 , wherein the adding to the blended base oil mixture is done such that the lubricating oil composition comprises 0.75 to 3.5 wt % of the viscosity modifier. 
     
     
         22 . The process of  claim 14 , wherein the adding to the blended base oil mixture is done such that the lubricating oil composition has a sulfated ash of 0.65 to 1.00 wt %. 
     
     
         23 . The process of  claim 14 , wherein the viscosity modifier comprises a shear stable non-dispersant olefin copolymer. 
     
     
         24 . The process of  claim 14 , wherein the blended base oil kinematic viscosity at 100° C. is from 6.50 mm 2 /s to 6.80 mm 2 /s. 
     
     
         25 . A method of operating an engine, comprising lubricating the engine with the lubricating oil composition of  claim 1 . 
     
     
         26 . The method of  claim 25 , wherein operating the engine with the lubricating oil composition provides an average cam lobe wear in a Cummins ISB test from 20 to 45 μm. 
     
     
         27 . The method of  claim 25 , wherein operating the engine with the lubricating oil composition provides an average cam and lifter wear in a Sequence IIIG test from 5 to 20 μm. 
     
     
         28 . The method of  claim 25 , wherein operating the engine with the lubricating oil composition provides a cam wear average in a Sequence IVA test from 1 to 10 μm. 
     
     
         29 . The method of  claim 25 , wherein operating the engine with the lubricating oil composition provides 5 to 16 mg total deposits in a Moderately High Temperature Thermo-Oxidation Engine Oil SimulationTest (TEOST MHT) by ASTM D7097-09. 
     
     
         30 . A method of operating an engine, comprising lubricating the engine with the lubricating oil composition made by the process of  claim 14 , wherein operating the engine with the lubricating oil composition provides one or more of:
 a) an average cam lobe wear in a Cummins ISB test from 20 to 45 μm;   b) an average cam and lifter wear in a Sequence IIIG test from 5 to 20 μm;   c) a cam wear average in a Sequence IVA test from 1 to 10 μm; or   d) 5 to 16 mg total deposits in a Moderately High Temperature Thermo-Oxidation Engine Oil Simulation Test (TEOST MHT) by ASTM D7097-09.