| 摘要 |
PROBLEM TO BE SOLVED: To provide an engine oil composition suppressed in oil consumption by combustion. SOLUTION: The engine oil composition is such that the number of carbon atoms of the base oil falls within the range from 22 to 36 and oil evaporation is suppressed by reducing low-carbon fraction and high-carbon fraction respectively. Thereby, evaporation of the oil in a crank chamber and consumption of the oil attributable to the combustion of part of the engine oil composition when a piston descends can be suppressed. Further, because being also reduced in the high-carbon fraction, this engine oil composition suppresses the increase in its whole viscosity associated with reducing the low-carbon fraction, thus preventing increase in the friction of the piston or the like. COPYRIGHT: (C)2005,JPO&NCIPI |
