Lubricating oil composition for diesel engine

Abstract

The present invention provides a lubricating oil composition for diesel engines, and more particularly to a lubricating oil composition for diesel engines, which comprises low ashes and no metals, has exceedingly high detergency and excellent antiwear so that it is suitably used for diesel engines equipped with an apparatus for after-treatment of exhaust gas. The lubricating oil composition for diesel engines, of which a lubricating base oil comprises a component (A): 2 to 30% by mass, based on the total amount of the composition, of a succinimide compound having an alkenyl group or an alkyl group of a number average molecular weight of 80 to 500 or a boronic compound thereof, and a component (B): 0.5 to 30% by mass, based on the total amount of the composition, of a succinimide compound having an alkenyl group of a number average molecular weight of 800 to 3,500 or a boronic compound thereof.

1 . A lubricating oil composition for diesel engines, comprising a lubricating base oil comprising a component (A): 2 to 30% by mass, based on the total amount of the composition, of a succinimide compound having an alkenyl group or an alkyl group of a number average molecular weight of 80 to 500 or a boronic compound thereof, and 
 a component (B): 0.5 to 30% by mass, based on the total amount of the composition, of a succinimide compound having an alkenyl group of a number average molecular weight of 800 to 3,500 or a boronic compound thereof.    
   
   
       2 . The lubricating oil composition for diesel engines according to  claim 1 , wherein the component (A) comprises a mono-based succinimide compound or a boronic compound thereof as the component (A).  
   
   
       3 . The lubricating oil composition for diesel engines according to  claim 1 , wherein the component (A)/the component (B), which represents the blending ratio by mass of the component (A) to the component (B), is in the range of 0.3 to 10.  
   
   
       4 . The lubricating oil composition for diesel engines according to  claim 1 , comprising boron content of 30 ppm by mass or more.  
   
   
       5 . The lubricating oil composition for diesel engines according to  claim 1 , comprising further an ashless antiwear agent of a component (C).  
   
   
       6 . The lubricating oil composition for diesel engines according to  claim 5 , wherein the ashless antiwear agent is a non-phosphoric antiwear agent.  
   
   
       7 . The lubricating oil composition for diesel engines according to  claim 1 , comprising a sulfated ashes content of 0.8% by mass or less.  
   
   
       8 . The lubricating oil composition for diesel engines according to  claim 1 , comprising no metals.