| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a lubricating oil composition having a satisfactorily low 40°C kinematic viscosity, 100°C kinematic viscosity, and 100°C HTHS viscosity while maintaining the 150°C HTHS viscosity. <P>SOLUTION: The lubricating oil composition includes a lubricating base oil having a 100°C kinematic viscosity of 1-6 mm<SP>2</SP>/s, a %C<SB>p</SB>of 70 or more, and a %C<SB>A</SB>of 2 or less and a viscosity index improver having a ratio A/B of less than 3.2 and a ratio C/B of less than 1.5 when added to the lubricating base oil, provided that (1) A=X-X<SB>0</SB>(wherein A is the thickening effect of the 100°C kinematic viscosity; X is the 100°C kinematic viscosity of the mixture of the lubricating base oil and a 3 mass% viscosity index improver; and X<SB>0</SB>is the 100°C kinematic viscosity of the lubricating base oil), (2) B=Y-Y<SB>0</SB>(wherein B is the thickening effect of the 150°C HTHS viscosity: Y is a 150°C HTHS viscosity of the mixture of the lubricating base oil and a 3 mass% viscosity index improver; and Y<SB>0</SB>is the 150°C HTHS viscosity of the lubricating base oil), and (3) C=Z-Z<SB>0</SB>(wherein C is the thickening effect of the 100°C HTHS viscosity: Z is the 100°C HTHS viscosity of the mixture of the lubricating base oil and a 3 mass% viscosity index improver; and Z<SB>0</SB>is the 100°C HTHS viscosity of the lubricating base oil). <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
