Mineral oil-based base oil, lubricating oil composition, internal combustion engine, and lubrication method for internal combustion engine

摘要

Disclosed herein is a mineral base oil satisfying the following requirements (I) to (V): (I): a kinematic viscosity at 100° C. is 2 mm2/s or more and less than 7 mm2/s; (II): a viscosity index is 100 or more; (III): a temperature gradient Δ|η*| of complex viscosity between two points of −10° C. and −25° C. is 60 Pa·s/° C. or less as measured with a rotary rheometer under conditions at an angular velocity of 6.3 rad/s and a strain amount of 0.1 to 100%; (IV): a content ratio [R1/R2] of a monocyclo paraffin component (R1) to a dicyclo to hexacyclo paraffin component (R2) is 0.70 or less by a volume ratio as measured in accordance with ASTM D2786; and (V): a % CA is less than 1.0.