Ashless stationary gas engine lubricant

Abstract

A low-ash, low-phosphorus lubricant composition suitable for use in a stationary gas engine includes an oil of lubricating viscosity, 1.0 to 8 percent of a succinimide dispersant, 0.8 to 4.0 percent of a hindered, ester-substituted phenol antioxidant, and at least one metal or ammonium-containing sulfonate detergent or metal or ammonium-containing phenate detergent, in an amount which provides 0.1 to 3.0 percent by weight of said sulfonate or phenate moieties exclusive of the weight of the metal or ammonium moieties. The lubricant contains up to 0.08 percent by weight phosphorus and up to 0.2 percent sulfated ash.

1 . A low-ash, low-phosphorus lubricant composition suitable for use in a two-cycle stationary gas engine, comprising: 
 (a) an oil of lubricating viscosity;    (b) about 1.0 to about 8.0 percent by weight of a succinimide dispersant;    (c) about 0.2 to about 4.0 percent by weight of a hindered phenol antioxidant;    (d) at least one metal or ammonium-containing sulfonate detergent or metal-or ammonium containing phenate detergent having a Total Base Number of up to about 100 on an oil free basis, in an amount which provides about 0.1 to about 3.0 percent by weight of sulfonate or phenate moieties exclusive of the weight of metal or ammonium moieties,    wherein said lubricant contains up to about 0.08 percent by weight phosphorus and up to about 0.2 percent sulfated ash.    
     
     
         2 . The composition of  claim 1  wherein the amount of the succinimide dispersant is about 1.2 to about 6.0 percent by weight.  
     
     
         3 . The composition of  claim 1  wherein the amount of the succinimide dispersant is about 1.5 to about 3.6 percent by weight.  
     
     
         4 . The composition of  claim 1  wherein the succinimide dispersant is the reaction product of a hydrocarbyl succinic anhydride and a condensed polyamine.  
     
     
         5 . The composition of  claim 1  wherein the hindered phenol antioxidant (c) is a hindered, ester substituted phenol antioxidant.  
     
     
         6 . The composition of  claim 1  wherein the amount of the hindered phenol antioxidant (c) is about 0.75 to about 3.0 percent by weight.  
     
     
         7 . The composition of  claim 1  wherein the metal in component (d) is calcium.  
     
     
         8 . The composition of  claim 1  wherein the detergent of (d) is a neutral detergent.  
     
     
         9 . The composition of  claim 1  wherein the detergent of (d) has a Total Base Number of up to about 50.  
     
     
         10 . The composition of  claim 1  wherein the detergent of (d) has a Total Base Number of up to about 30.  
     
     
         11 . The composition of  claim 1  wherein the amount of the sulfonate or phenate moieties of detergent of (d) is about 0.15 to about 2.0 percent by weight of the composition.  
     
     
         12 . The composition of  claim 1  wherein the amount of the sulfonate or phenate moieties of detergent of (d) is about 0.2 to about 1.5 percent by weight of the composition.  
     
     
         13 . The composition of  claim 1  further comprising a phosphorus ester.  
     
     
         14 . The composition of  claim 13 , wherein the phosphorus ester is present in an amount suitable to supply up to 0.08 percent by weight of phosphorus to the composition.  
     
     
         15 . The composition of  claim 13  wherein the phosphorus ester is triphenyl phosphite.  
     
     
         16 . The composition of  claim 1  wherein the sulfated ash value of the composition is about 0.05 to about 0.1 percent.  
     
     
         17 . The composition of  claim 1  wherein the phosphorus content of the composition is up to about 0.05 percent by weight.  
     
     
         18 . The lubricant composition of  claim 1 , said composition having a Total Base Number of up to about 5.  
     
     
         19 . The composition of  claim 1  further comprising a silicone defoamer.  
     
     
         20 . The composition prepared by combining the components of  claim 1 .  
     
     
         21 . A method of lubricating a two-cycle stationary gas engine, comprising supplying to said engine the lubricant composition of  claim 1.