The Fuel
NHRA regulations limit the composition of the fuel to a maximum of 90% nitromethane (Since 2008); the remainder is largely methanol. However, this mixture is not mandatory, and less nitromethane may be used if desired.
Kenny Bernstein was the first drag racer in NHRA history to break 300 mph (480 km/h) in such a class of car on the 1/4 mile in March, 1992.
While nitromethane has a much lower energy density (11.2 MJ/kg) than either gasoline (44 MJ/kg) or methanol (22.7 MJ/kg), an engine burning nitromethane can produce up to 2.3 times more power than an engine burning gasoline. This is made possible by the fact that, in addition to fuel, an engine must admit air in order to generate force: 14.7 kg of air is required to burn one kilogram of gasoline, compared to only 1.7 kg of air for one kilogram of nitromethane. This means that an engine can burn 8.7 times more nitromethane than gasoline.
Nitromethane also has a high temperature of vaporization, meaning that it will absorb substantial engine heat as it vaporizes, providing an invaluable cooling mechanism. The laminar flame speed and combustion temperature are higher than gasoline at 0.5 m/s and 2400 °C respectively. Power output can be increased by using very rich air fuel mixtures. This is also something that helps prevent pre-ignition, something that is usually a problem when using nitromethane.
Due to the relatively slow burn rate of nitromethane, very rich fuel mixtures are often not fully ignited and some remaining nitromethane can escape from the exhaust pipe and ignite on contact with atmospheric oxygen, burning with a characteristic yellow flame. Additionally, after sufficient fuel has been combusted to consume all available oxygen, nitromethane can combust in the absence of atmospheric oxygen, producing hydrogen, which can often be seen burning from the exhaust pipes at night as a bright white flame. In a typical run the engine can consume as much as 22.75 Gallons (103 Liters) of fuel during warmup, burnout, staging, and the quarter-mile run.
Read more about this topic: Top Fuel
Famous quotes containing the word fuel:
“Beware the/easy griefs, that fool and fuel nothing./It is too easy to cry “AFRIKA!”/and shock thy street,/and purse thy mouth,/and go home to thy “Gunsmoke,” to/thy “Gilligan’s Island” and the NFL.”
—Gwendolyn Brooks (b. 1917)
“I had an old axe which nobody claimed, with which by spells in winter days, on the sunny side of the house, I played about the stumps which I had got out of my bean-field. As my driver prophesied when I was plowing, they warmed me twice,—once while I was splitting them, and again when they were on the fire, so that no fuel could give out more heat. As for the axe,... if it was dull, it was at least hung true.”
—Henry David Thoreau (1817–1862)