Method for the control of deposit formation in formulated lubricating oil by use of ionic liquids as additives

A method for reducing friction and wear in internal combustion engines lubricated with a lubricating oil comprising a base oil and an additive amount of at least one additive selected from anti-oxidant, anti-wear, detergent or dispersant by the addition to the lubricating oil of an additive amount of one or more ionic liquids comprising,

• (a) heating the ionic liquid alone to a temperature of from 30 to 120° C.,
• (b) adding to the heated ionic liquid a zinc or molybdenum dialkyl dithiophosphate or zinc or molybdenum dialkyl dithiocarbamate,
• (c) heating the mixture of(b) to a temperature between 50 to 120° C. for a time sufficient for the ionic liquid and the zinc or molybdenum dialkyl dithiophosphate or dialkyl dithiocarbamate to interact, and
• (d) adding resulting compound from(c) into base oil to make the lubricating oil.