Additives
Additives are complicated chemicals which are divided to two major groups. The first group includes materials that prolong oil life. If these additives are not added to base oil and this oil is used in engine, after very short distance, oil must be changed.
The second group includes materials that extend the operating range of oil. For instance, usual base oils are hardened gradually and frozen in the end. So, with this oil, cannot travel to the cold regions. With adding special additives to oil, it will enable the engine to work easily in diverse weather conditions.
Additive types and their operations
Aim of using
operation
Detergents
Cleaning and prevention of acidic sludge deposits formation on the engine inner parts
Neutralization of acids in oil which are formed due to oil oxidation and fuel consumption
Dispersants
Dispersing of contamination particles inside the oil
Disperse the carbon particles and acidic sludge as suspension and therefore prevent oil from deposit forming
Antioxidant
Prevention of oil oxidation and therefore acidic sludge formation
Converts peroxides and hydro peroxides due to oil molecules break to the inactive molecules
VI-Improvers
Reduction of viscosity changes versus temperature changes
The solubility of polymer in oil is increased due to temperature increase, and this fact decreases the speed of oil viscosity reduction due to temperature increase
Anti-Corrosion, Anti-Rust
Decrease of metal parts’ corrosion and rust
Prevent metal surfaces and corrosive organic acids and water from reacting by creating protective layer on the metal surface
Anti-Foam
Prevent oil from foaming, reduce the oil surface tension
With reducing oil layer surface tension, the surface of foam bubbles become unstable and torn quickly
Friction Modifiers
Reduction of friction between machinery moving surfaces in boundary lubricating condition
This modifier is absorbed to metal surface via polar end and therefore two surfaces contact and friction is reduced
Pour Point Depressants
Prevention of oil freezing in low temperatures
Prevention of regular crystalline lattices formation which can lock up oil molecules within itself
Anti-Wear Agents
Prevention of machinery parts abrasion
Like the friction-modifiers, but the difference is that the additive forms chemical compound and therefore mechanism of surfaces contact prevention is possible in harder condition
EP Agent
Prevention of metal surfaces abrasion in boundary lubricating condition and very high pressures
Like the anti-frictions with forming stronger compounds