Internal-combustion engine lubrican composition

摘要

[PROBLEMS TO BE SOLVED BY THE INVENTION] To provide a lubricating oil composition excellent in cleanability at high temperature around a piston in spite of its superlow-ash composition substantially free of ashes derived from a metal·base dergent, which cannot be realized by conventional techniques. [MEANS FOR SOLVING THE PROBLEMS] The lubricating oil composition for internal combustion engines, containing the GCD550°C + heavy fraction at 6% by volume or more, and having a sulfated ash content of 0.6% by mass or less and content of an additive containing a boron-base compound of 0.02% by mass or more as boron.