abstract |
The present invention provides a method for lubricating an internal combustion engine, comprising a step of supplying a lubricating oil composition to a cylinder of an internal combustion engine having an average effective pressure of 1.3 MPa or more, and obtaining the lubricating oil composition by ashing the lubricating oil composition in air at 950°C The integrated intensity ratio of the ash content to the CaO peak in the X-ray diffraction spectrum is 16.5% or less. |