Lubricant composition for internal combustion engine

A lubricating oil composition used in an internal combustion engine, comprising:

• a lubricating base oil;
• a disulfide compound as a component (A), the disulfide compound represented by formula (1) as follows and/or formula (2) as follows;
• a no-boron-containing ashless dispersant as a component (B), the no-boron-containing ashless dispersant having in its side chain:
• an alkyl group having a number average molecular weight of 500 to 3000;
• or an alkenyl group having a number average molecular weight of 500 to 3000;
• and
• a boron-containing ashless dispersant as a component (C), the boron-containing ashless dispersant having in its side chain:
• an alkyl group having a number average molecular weight of 500 to 4000;
• or an alkenyl group having a number average molecular weight of 500 to 4000,
• R1OOC-A1-S—S-A2-COOR2 (1)
• where:
• R1 and R2 each represent a hydrocarbyl group having 1 to 30 carbon atoms, the hydrocarbyl group optionally containing an oxygen atom, a sulfur atom or a nitrogen atom;
• and A1 and A2 each represent a group represented by CR3R4 or a group presented by CR3R4—CR5R6, in which R3 to R6 each represent a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms,
• R7OOC—CR9R10—CR11(COOR8)—S—S—CR16(COOR13)—CR14R15—COOR12 (2)
• where:
• R7, R8, R12 and R13 each represent a hydrocarbyl group having 1 to 30 carbon atoms, the hydrocarbyl group optionally containing an oxygen atom, a sulfur atom or a nitrogen atom;
• and R9 to R11 and R14 to R16 each represent a hydrogen atom or a hydrocarbyl group having 1 to 5 carbon atoms.