Trunk piston type diesel engine lubricating oil composition

摘要

A lubricant composition for medium-speed trunk piston diesel engines which comprises: as a base oil for the lubricant, one or more members selected from the group consisting of a mineral oil and a synthetic oil having a dynamic viscosity at 100°C of 3 mm2/s or more but less than 6 mm2/s, a mineral oil and a synthetic oil having a dynamic viscosity at 100°C of 6 mm2/s or more but less than 9 mm2/s and a mineral oil and a synthetic oil having a dynamic viscosity at 100°C of 9 mm2/s or more but less than 13 mm2/s; and, as a metal-based detergent, one or more kinds of calcium salicylate detergents optionally combined with a calcium phenate detergent, has a dynamic viscosity at 100°C of 7.0-11.0 mm2/s or lower and a high shear viscosity at 70°C of 7.0-20.0 mPa.s, and has a base number determined by the perchloric acid method of 7-55 mgKOH/g.