Engines, transmissions and other mechanical systems contain hundreds of
moving parts. Though the metal surfaces of these parts look smooth, they are
actually full of microscopic peaks and valleys. When the peak of one surface
touches its mating surface, it causes damage. Damage may lead to component
surface or wear. Failure prevention and wear reduction are the primary functions
REFINED PETROLEUM OILS
Conventional oils - the oils most people are familiar with - are refined from
crude oil. Refining is a process of physically separating light oil components
from heavy ones.
Crude oil contains millions of different kinds of molecules. Many are similar
in weight but different in structure. The refining process cannot distinguish
such molecules, so a wide assortment of molecules is present in the finished
lubricant made from crude oil stocks.
Some crude oil molecules are not beneficial to the lubrication process. For
example, paraffin causes refined lubricants to thicken and flow poorly in cold
temperatures. Molecules containing sulfur, nitrogen and other elements invite
the formation of sludge and other products of lubricant breakdown, especially in
high-temperature applications. Sludge and breakdown products significantly
increase wear rates.
The assorted molecules of refined lubricants also have different shapes,
making lubricant surfaces irregular at the molecular level. As lubricant layers
flow across one another during the lubrication process, these irregularities
create friction, which consumes power, reduces efficiency and increases heat and
"The main advantage of mineral oils is their low cost.
The main limitation of mineral oils is that…the lubricant-sized molecules have a
variety of structures ranging from the best to the worst (in terms of wear
control)." - A. Jackson, Mechanical Engineering Transactions
Synthetic lubricants are chemically engineered from pure chemicals rather
than refined from crude oil. That gives them significant advantages over refined
Pure - The feedstocks from which synthetic lubricants are made do not contain
sulfur, nitrogen or other elements that invite the formation of sludge and other
products of lubricant breakdown. Synthetic lubricants can be used in higher
temperatures than refined lubricants without breaking down. Their resistance to
breakdown also allows them to be used longer than refined lubricants can be
used. Lubricated systems stay cleaner and last longer with synthetic lubricants.
Synthetic lubricants differ from refined oil in three
key ways: synthetics are pure, their molecular structure is uniform, and they
may be designed to work in applications in which refined oils cannot.
Uniform - The feedstocks from which synthetic lubricants are made feature
uniform and smooth molecular structures, which ensures low friction as lubricant
layers slide across one another. Reduced friction increases energy through-put
for greater fuel efficiency and power and reduces heat and wear for longer
Molecular uniformity also helps synthetics resist thinning in heat and
thickening in cold, which helps them protect better than refined oils over a
system's operating temperature range and helps ensure secure sealing.
"Field experience has shown that synthetics can give
economic benefits when used in place of mineral oils which were working
satisfactorily. The benefits fall in five general areas:
Designable - Many different kinds of feedstock may be used to
create synthetic lubricants, allowing a synthetic to be designed for virtually
any application. Some feedstocks are ideal for use in extremely cold
environments. Others are perfect for use in extreme heat. Some are extremely
safe in applications in which refined lubricants pose a fire or explosion
hazard. Refined oils simply do not offer the design flexibility synthetics
The design flexibility of synthetics also allows them to be tailored very
specifically to the needs of everyday applications, such as automotive engines,
commercial equipment or much industrial machinery. That specificity helps ensure
long life and peak power, performance and fuel economy from the lubricated
system and long lubricant life.