Lubricant composition for internal combustion engine oil

Abstract

The present invention provides a lubricating oil composition for internal combustion engines which includes a boronated imide-based dispersant, or the boronated imide-based dispersant and a non-boronated imide-based dispersant, in which a boron content (B % by mass) derived from the boronated imide-based dispersant and a nitrogen content (N % by mass) derived from the boronated imide-based dispersant or derived from the boronated imide-based dispersant and the non-boronated imide-based dispersant satisfy the following formula (I): N≧B+0.05 (I); and a phosphorus content (P % by mass) and a content of a metal component (M % by mass) derived from a metallic detergent on the basis of a total amount of the composition satisfy any of the following requirements A to C: A: P<0.03 and M<0.05; B: P<0.03 and 0.05≦M≦0.12; and C: 0.03≦P≦0.06 and M<0.05. The lubricating oil composition for internal combustion engines can be considerably reduced in content of ZnDTP having a large phosphorus content or a metallic detergent while maintaining a good wear resistance for aluminum materials.

1 . A lubricating oil composition comprising a boronated imide-based dispersant, or comprising the boronated imide-based dispersant and a non-boronated imide-based dispersant, in which a boron content B, in mass %, of the boronated imide-based dispersant and a nitrogen content N, in mass %, of the boronated imide-based dispersant or the boronated imide-based dispersant and the non-boronated imide-based dispersant satisfy formula (I):
     N≧B+ 0.05   (I),
   
       and a phosphorus content P, in mass %, and a content M, in mass %, of a metal component of a metallic detergent on the basis of a total amount of the composition satisfy any one of the following requirements A to C:
   A: P<0.03 and M<0.05; 
   B: P<0.03 and 0.05≦M≦0.12; and
 
   C: 0.03≦P≦0.06 and M<0.05.
 
 
     
     
         2 . The lubricating oil composition of  claim 1 , wherein B and N satisfy formula (II):
     N≧B+ 0.1   (II).
   
     
     
         3 . The lubricating oil composition of  claim 1 , further comprising an anti-wear agent comprising sulfur. 
     
     
         4 . The lubricating oil composition of  claim 3 , wherein the anti-wear agent is a disulfide compound represented by formula (3):
   R 1 OOC-A 1 -S 2 -A 2 -COOR 2    (3)
   
       wherein R 1  and R 2  are each independently a hydrocarbon group having 1 to 30 carbon atoms which may comprise an oxygen atom, a sulfur atom or a nitrogen atom; and A 1  and A 2  are each independently a divalent hydrocarbon group having 1 to 12 carbon atoms. 
     
     
         5 . The lubricating oil composition of  claim 1 , comprising the boronated imide-based dispersant and the non-boronated imide-based dispersant. 
     
     
         6 . The lubricating oil composition of  claim 1 , wherein P and M satisfy requirement A. 
     
     
         7 . The lubricating oil composition of  claim 1 , wherein P and M satisfy requirement B. 
     
     
         8 . The lubricating oil composition of  claim 1 , wherein P and M satisfy requirement C. 
     
     
         9 . The lubricating oil composition of  claim 2 , comprising the boronated imide-based dispersant and the non-boronated imide-based dispersant. 
     
     
         10 . The lubricating oil composition of  claim 2 , wherein P and M satisfy requirement A. 
     
     
         11 . The lubricating oil composition of  claim 2 , wherein P and M satisfy requirement B. 
     
     
         12 . The lubricating oil composition of  claim 2 , wherein P and M satisfy requirement C. 
     
     
         13 . The lubricating oil composition of  claim 2 , further comprising an anti-wear agent comprising sulfur.