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Nitrogen in tires is becoming a popular replacement for standard air. Nitrogen is all around us... the air we breathe is 78% nitrogen, 21% oxygen and the rest is small amounts of other gasses. When it comes to tire inflation, nitrogen has many advantages over oxygen. With nitrogen tire inflation, improvements can be noted in a vehicle's handling, fuel efficiency and tire life through better tire pressure retention, improved fuel economy and cooler running tire temperatures.
A few points to be clarified
1. Air is 78%
nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire,
it's already 78% nitrogen. Many of the so called nitrogen generators
don't produce much more than 90% nitrogen.
2. At relatively low
pressures (ie tire pressures) N2, O2 and water vapor will all behave as
ideal gases, and follow PV=nRT. Pressure will increase or decrease to
the same extent as the temperature increases or decreases regardless of
which gas is in the tire. (Even at 300 psi, which is about 20 atm,
there is little deviation from ideality.) Therefore the comments about
N2 not changing in pressure as the temperature changes are without
merit.
3. The rate of effusion (or diffusion) of a gas through
a porous membrane depends on the molar mass and to some degree on the
molecular diameter. N2 and O2 are almost the same size and N2 is
lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse
out of the tire, nitrogen would do it more quickly. Luckily, tires are
designed not to be porous membranes.
4. N2 and O2 both have
essentially the same specific heat capacity, about 1.0 J/gK, and
thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific
heat capacity of about 2 J/gK. But remember, water vapor will
constitute less than 1% of the air in the tire. So the idea that N2 has
different heat handling properties is also without merit.
5.
The ozone, O3, in the atmosphere, which is a ground level pollutant,
will do a great deal more damage to your tires than the O2 inside the
tire. For instance, don't leave a condom out in the air in Los Angeles
for a few days. It will develop lots of tiny holes and weaken.
How its done:
1st all the air in the tires need to be removed and vacuum needs to be created..... and then Nitrogen is filled in the tires...
Where its done:
as of now.... Bombay Tires located at Milan Subway has this system.....
pls u guys kno any other place please let us know....
How much its costs:
its seen on the web tht in US it costs around $10 per tire.....
but in India .... it cost only Rs. 200/- for all 4 tires.... some places heard that its done for 100/- as well
ADMIN: Posts Merged
A few points to be clarified
1. Air is 78%
nitrogen, N2, and 21% oxygen, O2. So even if you put air in the tire,
it's already 78% nitrogen. Many of the so called nitrogen generators
don't produce much more than 90% nitrogen.
2. At relatively low
pressures (ie tire pressures) N2, O2 and water vapor will all behave as
ideal gases, and follow PV=nRT. Pressure will increase or decrease to
the same extent as the temperature increases or decreases regardless of
which gas is in the tire. (Even at 300 psi, which is about 20 atm,
there is little deviation from ideality.) Therefore the comments about
N2 not changing in pressure as the temperature changes are without
merit.
3. The rate of effusion (or diffusion) of a gas through
a porous membrane depends on the molar mass and to some degree on the
molecular diameter. N2 and O2 are almost the same size and N2 is
lighter than O2 (28 g/mol vs 32 g/mol) so if either gas were to effuse
out of the tire, nitrogen would do it more quickly. Luckily, tires are
designed not to be porous membranes.
4. N2 and O2 both have
essentially the same specific heat capacity, about 1.0 J/gK, and
thermal conductivity, about 0.00026 W/cmK. Water vapor has a specific
heat capacity of about 2 J/gK. But remember, water vapor will
constitute less than 1% of the air in the tire. So the idea that N2 has
different heat handling properties is also without merit.
5.
The ozone, O3, in the atmosphere, which is a ground level pollutant,
will do a great deal more damage to your tires than the O2 inside the
tire. For instance, don't leave a condom out in the air in Los Angeles
for a few days. It will develop lots of tiny holes and weaken.
How its done:
1st all the air in the tires need to be removed and vacuum needs to be created..... and then Nitrogen is filled in the tires...
Where its done:
as of now.... Bombay Tires located at Milan Subway has this system.....
pls u guys kno any other place please let us know....
How much its costs:
its seen on the web tht in US it costs around $10 per tire.....
but in India .... it cost only Rs. 200/- for all 4 tires.... some places heard that its done for 100/- as well
ADMIN: Posts Merged
