LUBRICANT OIL COMPOSITION FOR INTERNAL COMBUSTION ENGINES AND METHOD FOR PRODUCING SAME, AND METHOD FOR PREVENTING PRE-IGNITION

Provided are: a lubricating oil composition for internal combustion engines containing a base oil (A), a metal-based detergent (B) containing a calcium-based detergent (B1), a zinc dialkyldithiophosphate (C), and a molybdenum-containing compound (D), wherein the calcium atom-equivalent content of the component (B1) is more than 100 ppm by mass and 600 ppm by mass or less based on the total amount of the lubricating oil composition, the magnesium atom-equivalent content of a magnesium-based detergent (B2) is less than 200 ppm by mass based on the total amount of the lubricating oil composition, the sodium atom-equivalent content of a sodium-based detergent (B3) is less than 200 ppm by mass based on the total amount of the lubricating oil composition, the content ratio of the phosphorus atom derived from the component (C) to the calcium atom derived from the component (B1) [P/Ca] is 0.25 or more by mass, and the sulfated ash content is 0.7% by mass or less; and a method for producing the lubricating oil composition. Also provided is a method for suppressing pre-ignition, using the lubricating oil composition for internal combustion engines. The lubricating oil composition has a sufficient friction-reducing effect, can prevent an occurrence of LSPI in spark-ignition internal combustion engines, and has reduced adverse effects on exhaust gas purification devices. The invention provides the lubricating oil composition for internal combustion engines, a method for producing it, and a method for suppressing pre-ignition using the lubricating oil composition for internal combustion engines.