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发帖数: 1632 | 1 What is the difference between conventional motor oil and synthetic
motor oil?
Answer
synthetic motor oil lasts longer and is better to use.
More detailed answer
Motor oil is designed to serve many different purposes within a cars
engine. While the primary function is to simply lubricate all the moving
parts and provide protection from wear and corrosion, it also is
intended to keep the engine cool and free from small pieces of debris.
Conventional motor oils are made from crude oil which has been is pumped
from the ground and then processed in a refinery to create a base oil.
Additives are then mixed into the base oil to change the viscosity,
protection properties and heat breakdown levels of the oil.
Synthetic oil is also created in a similar manner to a conventional
engine oil, using a base oil combined with a series of additives. The
difference lies in the fact that synthetic motor oils are created
utilizing a specially "synthesized" base oil where the size of the oil
molecules are all of an ideal weight and of a consistent size. While a
conventional motor oil, despite the refining processes, is made up of
different molecule sizes which are mixed together, along with various
waxes and impurities, a fully synthetic oil is made to provide a much
purer base oil, with less waxes and with a uniform ideal particle size
to help increase the oils viscosity level. Added to this ideal base oil
is a combination of more technically sophisticated additives than are
used with the conventional oils.
The additives which are used in the production of synthetic oils can
help to create an extremely stable engine oil which will sustain the
correct viscosity levels across a large range of temperatures and which
will flow properly at lower temperatures when compared against
conventional oils. Additional friction inhibitors which are activated at
lower temperatures than those of conventional oils, are generally
included in synthetic motor oils, to provide improved protection for the
engine from the moment of start-up.
This means that the synthetic oil is designed with improved lubricate
properties and enhanced viscosity to provide superior protection from
engine wear, reduced heat breakdown volatility for decreased oil
consumption, improved fuel mileage, easier engine cold starting and a
reduction in engine deposits.
When deciding whether it is best to use synthetic or conventional car
engine oils, it is always best to bear in mind the age of the vehicle as
problems and oil leaks can occur when switching to a fully synthetic oil
with an old engine. This is because there can be a build-up of waxes and
sludge left by conventional oils over time, which may mask worn engine
seals. The introduction of a synthetic oil may cause the detergents in
the synthetic oil to break down and clean-up this protective build-up
which is maintaining the seal, this will then result in oil leaking
through the engine seals when the oil thins as it gets hot.
Semi-synthetic oils are an alternative to buying a pure synthetic oil.
These combine a certain quantity of synthetic base oil with a
conventional base oil in order to provide a high quality oil which can
be used to gain some of the protection benefits of a fully synthetic for
slightly older vehicles. However semi-synthetic engine oils do not
typically include all the synthetic oil's advanced additives.
Whilst older vehicles are frequently better using conventional oils due
to the engine seals, new cars which experience normal day-to-day use
with its short journeys, traffic jams, extreme temperature changes, etc,
can benefit from the extra protection of afforded by synthetics, but it
is always safest to refer to the manufacturer's recommendations before
making any changes.
Reference:
http://wiki.answers.com/Q/What_is_the_difference_between_conven
tor_oil_and_synthetic_motor_oil#ixzz1NQnbYMPj |
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