Lubricating oil composition for gas engines

Abstract

The lubricating oil composition for gas engine of the present invention contains (A) a base oil, (B1) an overbased calcium salicylate, (B2) an overbased sodium sulfonate, (C1) an amine-based antioxidant, and (C2) a phenol-based antioxidant, a total content of the amine-based antioxidant (C1) and the phenol-based antioxidant (C2) being 4 mass % or more on a basis of the whole amount of the composition.

1 : A lubricating oil composition for gas engine, comprising (A) a base oil, (B1) an overbased calcium salicylate, (B2) an overbased sodium sulfonate, (C1) an amine-based antioxidant, and (C2) a phenol-based antioxidant, a total content of the amine-based antioxidant (C1) and the phenol-based antioxidant (C2) being 4 mass % or more on a basis of the whole amount of the composition. 
     
     
         2 : The lubricating oil composition for gas engine according to  claim 1 , further comprising (D) a heterocyclic compound selected from the group consisting of at least one a compound represented by the following general formula (I) and at least one compound represented by the following general formula (II): 
       
         
           
           
               
               
           
         
         wherein R 1  represents a linear or branched alkyl group having 7 to 17 carbon atoms; and n represents 6 to 18. 
       
     
     
         3 : The lubricating oil composition for gas engine according to  claim 1 , further comprising (C3) a molybdenum-based antioxidant. 
     
     
         4 : The lubricating oil composition for gas engine according to  claim 1 , wherein the total content of the amine-based antioxidant (C1) and the phenol-based antioxidant (C2) is 5 mass % or more on a basis of the whole amount of the composition. 
     
     
         5 : The lubricating oil composition for gas engine according to  claim 1 , further comprising (B3) a basic calcium sulfonate. 
     
     
         6 : The lubricating oil composition for gas engine according to  claim 1 , further comprising (E1) a polymethacrylate as (E) a viscosity index improver. 
     
     
         7 : The lubricating oil composition for gas engine according to  claim 1 , wherein a calcium content is 0.05 to 0.4 mass %, and a sodium content is 0.005 to 0.1 mass % on a basis of the whole amount of the composition. 
     
     
         8 : The lubricating oil composition for gas engine according to  claim 1  that is suitable for use in a gas heat pump. 
     
     
         9 : A method for producing a lubricating oil composition for gas engine, comprising blending (B1) an overbased calcium salicylate, (B2) an overbased sodium sulfonate, (C1) an amine-based antioxidant, and (C2) a phenol-based antioxidant in (A) a base oil to produce a lubricating oil composition for gas engine,
 a total blending amount of the amine-based antioxidant (C1) and the phenol-based antioxidant (C2) being 4 mass % or more on a basis of the whole amount of the composition.   
     
     
         10 : A composition comprising a base oil, an overbased calcium salicylate, an overbased sodium sulfonate, an amine-based antioxidant, and a phenol-based antioxidant, a total content of the amine-based antioxidant and the phenol-based antioxidant being 4 mass % or more based on the total mass of the composition. 
     
     
         11 : A gas engine comprising the composition of  claim 10 .