Study ofTribological Performance for Carbon Nanotubes (CNTs) as an Additive in Engine Lubricating Oil

Engine oil is primarily organic compound contains carbon, hydrogen, and
oxygen. It is from the wide separation of petroleum which consists a number of complex
mixtures of hydrocarbon compounds. Engine oil types, usually are from mineral-based
oil which synthesized by petroleum extraction and synthetic-based oil. Basically, the
tested engine oil will be chosen from the mineral-based engine oil since it has not been
well-modified as the synthetic-based engine oil. The mineral-based engine oil has
chemical additives in relation to the tribological performances.
In all these applications, it is necessary to use suitable engine oil for
specifications of an engine that has been recommended by the original equipment
manufacturer (OEM). Misuses of the different engine oil to the different engine will
cause in unexpected maintenance, increasing of operating costs, and decreasing of the
engine lifetime. The essential properties of engine oil are the viscosity and the wear of
engine oil.
The engine oil has varieties of functions such as reducing friction, as a coolant,
cleaning the trapped particles from machinery sheds, and as a sealant that could block the
surface from contaminants. Nowadays, the manufacturers are looking for better chemical
additive to increase the tribological performances in term of friction, lubrication, & wear.
As the emission regulations demand in high of good quality emission, and
increasing demanding in decreasing the engine oil element of phosphorus that can impact
the emission system control. Sulfur and metals are also under scrutiny as sulfur is
suspected as a poison of DeNOx catalysts, and ash (from metals) may plug aftertreatment
particulate traps. Modem engine oils rely heavily on ZDDP to provide antiwear,
anti-oxidation, and anticorrosion protection. Since ZDDP is rich in phosphorus,
sulfur, and zinc, it becomes an obvious target for emission control [I].