Lubricating oil composition with reduced phosphorus levels

Abstract

This invention is generally related to a low phosphorus lubricant for an internal combustion engine that provides superior deposit control while still retaining excellent viscosity control.

1 . A low phosphorus engine oil comprising: 
 4,4′-methylenebis(2,6-di-tert-butylphenol) and    an alkylated diphenylamine;    wherein    the weight ratio of 4,4′-methylenebis(2,6-di-tert-butylphenol) to said alkylated diphenylamine is greater than or equal to about 0.5; and    said engine oil produces less than or equal to 35 mg of total deposits according to a ASTM D7097 measurement.    
   
   
       2 . An engine oil according to  claim 1 , further comprising a zinc dialkyldithiophosphate; wherein said engine oil comprises about 600 ppm or less of phosphorus derived from said zinc dialkyldithiophosphate.  
   
   
       3 . An engine oil according to  claim 2 , further comprising an oil soluble organomolybdenum compound.  
   
   
       4 . A composition comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 4,4′-methylenebis(2,6-di-tert-butylphenol);    (c) an alkylated diphenylamine;    (d) at least one component selected from the group consisting of dispersants and detergents; and    (e) a zinc dialkyldithiophosphate;    wherein    said composition comprises about 600 ppm or less of phosphorus derived from said zinc dialkyldithiophosphate; and    the weight ratio of (b) to (c) is greater than or equal to about 0.5.    
   
   
       5 . A composition according to  claim 4 , further comprising 
 (f) an oil soluble organomolybdenum compound.    
   
   
       6 . A composition according to  claim 5 , wherein said oil soluble organomolybdenum compound comprises sulfur and is phosphorus-free.  
   
   
       7 . A composition according to  claim 6 , wherein the weight ratio of phosphorus to molybdenum is greater than or equal to 1.0.  
   
   
       8 . A composition according to  claim 6 , wherein the weight ratio of phosphorus to molybdenum is greater than 0.0 and less than 1.0.  
   
   
       9 . A composition according to  claim 6 , wherein the weight ratio of phosphorus to molybdenum is less than or equal to 1.0.  
   
   
       10 . A composition according to  claim 4  further comprising: 
 (g) a hindered phenolic antioxidant with the proviso that said hindered phenolic antioxidant is not 4,4′-methylenebis(2,6-di-tert-butylphenol).    
   
   
       11 . A composition according to  claim 10  wherein the sum of (b), (c) and (g) is less than or equal to about 1.5 wt. % of said composition.  
   
   
       12 . A composition according to  claim 6  further comprising 
 (g) a hindered phenolic antioxidant with the proviso that said hindered phenolic antioxidant is not 4,4′-methylenebis(2,6-di-tert-butylphenol).    
   
   
       13 . A composition according to  claim 12  wherein the sum of (b), (c) and (g) is less than or equal to about 1.5 wt. % of said composition.  
   
   
       14 . A composition according to  claim 4  wherein said oil of lubricating viscosity comprises up to about 15% by weight of a Group I baseoil.  
   
   
       15 . A composition comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 4,4′-methylenebis(2,6-di-tert-butylphenol);    (c) an alkylated diphenylamine;    (e) a zinc dialkyldithiophosphate; and    (f) an oil soluble organomolybdenum compound;    wherein:    the weight ratio of (b) to (c) is greater than or equal to about 0.5; and said composition produces less than or equal to about 35 mg of total deposits according to a ASTM D7097 measurement.    
   
   
       16 . A composition according to  claim 15  wherein said oil soluble organomolybdenum compound comprises sulfur and is phosphorus-free.  
   
   
       17 . A composition according to  claim 15 , wherein the weight ratio of phosphorus to molybdenum is greater than or equal to 1.0.  
   
   
       18 . A composition according to  claim 15 , wherein the weight ratio of phosphorus to molybdenum is greater than 0.0 and less than 1.0.  
   
   
       19 . A composition according to  claim 15 , wherein the weight ratio of phosphorus to molybdenum is less than or equal to 1.0.  
   
   
       20 . A composition according to  claim 15  further comprising: 
 (d) at least one component selected from the group consisting of dispersants and detergents.    
   
   
       21 . A composition according to  claim 15  further comprising: 
 (g) a hindered phenolic antioxidant with the proviso that said hindered phenolic antioxidant is not 4,4′-methylenebis(2,6-di-tert-butylphenol).    
   
   
       22 . A composition according to  claim 21  wherein the sum of (b), (c) and (g) is less than or equal to about 1.5 wt. % of said composition.  
   
   
       23 . A composition according to  claim 21  wherein said composition produces less than or equal to about 25 mg of total deposits according to an ASTM D7097 measurement.  
   
   
       24 . A composition according to  claim 20  further comprising 
 (g) a hindered phenolic antioxidant with the proviso that said phenolic antioxidant is not 4,4′-methylenebis(2,6-di-tert-butylphenol).    
   
   
       25 . A composition according to  claim 24  wherein the sum of (b), (c) and (g) is less than or equal to about 1.5 wt. % of said composition.  
   
   
       26 . A composition according to  claim 24  wherein said composition produces less than or equal to about 25 mg of total deposits according to an ASTM D7097 measurement.  
   
   
       27 . A composition comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 4,4′-methylenebis(2,6-di-tert-butylphenol); and    (c) an alkylated diphenylamine;    (d) at least one component selected from the group consisting of dispersants and detergents;    (e) a zinc dialkyldithiophosphate;    (f) an oil soluble organomolybdenum compound; and    (g) a hindered phenolic antioxidant with the proviso that said hindered phenolic antioxidant is not 4,4′-methylenebis(2,6-di-tert-butylphenol);    wherein said composition comprises:    about 600 ppm or less of phosphorus derived from said zinc dialkyldithiophosphate; and    about 50-400 ppm of molybdenum derived from said oil soluble organomolybdenum compound.    
   
   
       28 . A composition according to  claim 27 , wherein said oil soluble organomolybdenum compound comprises sulfur and is phosphorus-free.  
   
   
       29 . A composition according to  claim 27 , wherein the weight ratio of phosphorus to molybdenum is greater than or equal to 1.0.  
   
   
       30 . A composition according to  claim 27 , wherein the weight ratio of phosphorus to molybdenum is greater than 0.0 and less than 1.0.  
   
   
       31 . A composition according to  claim 27 , wherein the weight ratio of phosphorus to molybdenum is less than or equal to 1.0.  
   
   
       32 . A composition according to  claim 27  wherein said composition comprises about 550 ppm or less of phosphorus derived from said zinc dialkyldithiophosphate.  
   
   
       33 . A composition according to  claim 27  wherein said composition comprises about 100-250 ppm of molybdenum derived from said oil soluble organomolybdenum compound.  
   
   
       34 . A composition according to  claim 27  wherein said composition comprises about 500 ppm or less of phosphorus derived from said zinc dialkyldithiophosphate.  
   
   
       35 . A composition according to  claim 27  wherein said composition comprises about 250-400 ppm of molybdenum derived from said oil soluble organomolybdenum compound.  
   
   
       36 . An engine oil comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 4,4′-methylenebis(2,6-di-tert-butylphenol);    (c) 0.2 to 1.0 wt % of an alkylated diphenylamine;    (d) 1.0 to 12.0 wt % of at least one compound selected from the group consisting of dispersants and detergents;    (e) 200 to 600 ppm of phosphorus derived from zinc dialkyldithiophosphate; and    (f) 50 to 400 ppm of molybdenum derived from an oil soluble organomolybdenum compound;    wherein the weight ratio of (b) to (c) is greater than or equal to 0.5.    
   
   
       37 . An engine oil comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 0.1 to 1.5 wt % 4,4′-methylenebis(2,6-di-tert-butylphenol);    (c) an alkylated diphenylamine;    (d) 1.0 to 12.0 wt % of at least one compound selected from the group consisting of dispersants and detergents;    (e) 200 to 600 ppm of phosphorus derived from zinc dialkyldithiophosphate; and    (f) 50 to 400 ppm of molybdenum derived from an oil soluble organomolybdenum compound;    wherein the weight ratio of (b) to (c) is greater than or equal to 0.5.    
   
   
       38 . An engine oil according to  claim 37  further comprising: 
 (g) 0.1 to 0.5 wt % of any ester derived from 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid.    
   
   
       39 . An engine oil comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 4,4′-methylenebis(2,6-di-tert-butylphenol);    (c) 0.2 to 1.0 wt % of an alkylated diphenylamine, and    (d) 1.0 to 12.0 wt % of at least one compound selected from the group consisting of dispersants and detergents, and    (e) 300 to 600 ppm of phosphorus derived from zinc dialkyldithiophosphate; wherein the weight ratio of (b) to (c) is greater than or equal to 0.5.    
   
   
       40 . An engine oil according to  claim 39  further comprising: 
 (g) 0.1 to 0.5 wt % of any ester derived from 3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid.    
   
   
       41 . An engine oil comprising: 
 (a) a major amount of oil of lubricating viscosity selected from the group consisting of Group II, Group III, Group IV and synthetic ester base stocks;    (b) 0.1 to 1.5 wt % 4,4′-methylenebis(2,6-di-tert-butylphenol);    (c) an alkylated diphenylamine;    (d) 1.0 to 12.0 wt % of at least one compound selected from the group consisting of dispersants and detergents, and    (e) 300 to 600 ppm of phosphorus derived from zinc dialkyldithiophosphate;    wherein the weight ratio of (b) to (c) is greater than or equal to 0.5.    
   
   
       42 . A method of reducing the amount of total volatile organics produced by an internal combustion engine upon heating and oxidation of an engine oil comprising lubricating said engine with a composition according to  claim 1 .  
   
   
       43 . A method of reducing the amount of deposits in an internal combustion engine, comprising lubricating said engine with a composition according to  claim 1 .  
   
   
       44 . A method of reducing the poisoning of the catalyst in an internal combustion engine emission system comprising lubricating said engine with a composition according to  claim 1.