Marine cylinder oil composite additive

A marine cylinder oil composite additive, wherein, based on the total weight of the composite additive, it comprises:

• 15-25% sulfonate detergent with superhigh base number, 35-45% phenolate detergent with superhigh base number, 20-30% naphthenate detergent with superhigh base number, 0-8% dispersing agent, 0-4% antiwear agent, and 10-20% Group I base oil with high viscosity index which is selected from the group consisting of 400SN, 500SN and 650SN;
• said sulfonate detergent with superhigh base number is C22-C30 linear alkyl benzene calcium sulphonate, wherein the base number thereof is 395-430 mgKOH/g;
• said phenolate detergent with superhigh base number is C18-C24 alkyl sulfurized calcium phenolate, wherein the base number thereof is 290-310 mgKOH/g;
• said naphthenate detergent with superhigh base number is C20-C30 long chain alkyl calcium naphthenate, wherein the base number thereof is 390-420 mgKOH/g;
• said dispersing agent is selected from the group consisting of mono-polyisobutylene succinimide, bis-polyisobutylene succinimide and multi-polyisobutylene succinimide;
• said antiwear agent is zinc long-chain alkyl thiophosphate with the structure corresponding to the following formula,
• wherein R1, R2, R3 and R4 are long-chain primary alkyl groups each comprising 12-18 carbon atoms, or R1, R2, R3 and R4 are long-chain secondary alkyl groups each comprising 12-16 carbon atoms.