| NITROUS
IN THE COMBUSTION PROCESS |
| For racing purposes, nitrous oxide
is usually contained in an aluminum cylinder; available
in a variety of sizes ranging from 2.5 lbs to 20 lbs.
While retained in the cylinder the nitrous is in a liquid
form and held under high pressure. When it’s released
from the cylinder into the intake tract its physical state changes
from a liquid to a gas. This transformation occurs as the
nitrous is released from an area of extreme pressure (the aluminum
cylinders are pressurized to approximately 1000 P.S.I.)
into the vacuum of the intake manifold. This change in state
is usually referred to as the nitrous ‘boiling’. |
| Water boils at 212° Fahrenheit
or 100° Centigrade. However, if held under pressure
in an automobile cooling system, for example, the coolant
will remain a liquid, even above boiling point. Though
inadvisable, if a radiator cap is removed under these
conditions and the pressure relieved, the water would expand
and boil instantly. So it is with nitrous oxide, while under
pressure it exists in a liquid form, but when exposed to an instant
reduction in pressure the liquid expands and boils and the
nitrous oxide is converted to gas. |
| It takes energy to enable the nitrous
to expand and boil. This energy is produced by the heat,
which is absorbed from the surrounding air/gas in the
intake tract. The end result is an intake charge that
is cool, dense and oxygen rich - the ideal recipe for
producing more power. |
| When the additional fuel required
for nitrous is introduced in such a way that it is exposed
to the full force of the expanding nitrous, it is atomized
completely. This promotes improved burning in the combustion
chamber and, as a direct result, power-output is increased.
|
| Nitrous Oxide (also known by the
chemical formula N2O) comprises two atoms of nitrogen
and one of oxygen and the heat of the combustion breaks
the chemical bond that holds them together. Without heat,
the three atoms would remain bonded and, consequently, the oxygen
atom rendered powerless - unable to play its role in
the combustion process. This is why inhaling nitrous
can lead to asphyxiation, even though it has a higher
oxygen content than air. Your body cannot produce the heat
necessary (about 525° Fahrenheit) to break the bond between
the nitrogen and the oxygen; leaving the oxygen content
useless for respiration. |
| Gasses are often considered in
terms of moles. The definition of a mole is the amount
of substance that contains Avogadro’s number of
atoms or molecules. Though this number remains the same
(6.02 x 10 to the power of 23), the weight of a mole will
vary depending on the atomic weight of the molecule in question.
A mole of any substance occupies 22.4 liters at standard
pressure and temperature. The fact remains that all gasses
have the same molar volume in similar conditions. So, if
a cylinder can draw two moles of air on an intake stroke, it can
also consume the same volume of nitrous. By volume, air contains
21% oxygen compared to nitrous, which is 50% oxygen. For
every two moles of Nitrous Oxide (N2O) introduced to the cylinder,
there are two moles of Nitrogen (N2) and one mole of Oxygen
(O2), as can be seen in the equation below: |
2
N2O ==> 2 N2 + 1 O2 |
| There lies the hidden advantage
of Nitrous Oxide. Since every mole has the same volume,
it’s clear that two moles of nitrous drawn into
the cylinder become three moles through the combustion
process. This further raises combustion pressures and
increases the power-producing potential of the engine. |
| |
