2006-08-27 05:46:39 · 7 answers · asked by Dan 5 in Cars & Transportation ➔ Aircraft
The octane rating is a measure of the autoignition resistance of gasoline (petrol) and other fuels used in spark-ignition internal combustion engines
Octane is measured relative to a mixture of isooctane (2,2,4-trimethylpentane, an isomer of octane) and n-heptane. An 87-octane gasoline, for example, has the same knock resistance as a mixture of 87 vol-% isooctane and 13 vol-% n-heptane. This does not mean, however, that the gasoline actually should contain these chemicals in these proportions. It simply means that it has the same autoignition resistance as the described mixture.
A high tendency to autoignite, or low octane rating, is undesirable in a gasoline engine but desirable in a diesel engine. The standard for the combustion quality of diesel fuel is the cetane number. A diesel fuel with a high cetane number has a high tendency to autoignite, as is preferred.
Check the wikipedia link for more
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2006-08-27 05:52:18 · answer #1 · answered by Starreply 6 · 3⤊ 0⤋
Octane is an 8 carbon chain, with 18 hydrogens attached. Octane rating is a measure of how much octane is in the mixture of gasoline, which can have anywhere from 5 carbon chains through 10 carbon chains. Internal conustion engines like octane. They also lke branched chains better than straight. Crude oil only has a certain amount of octane, so gasoline manufacturers use chemical pocesses to cause chains to recombine to make more octane needed for gasoline.
2006-08-27 05:53:06 · answer #2 · answered by science teacher 7 · 1⤊ 0⤋
Octane is the "squeeze" factor.
Engines are designed to work at a specific compression. On the power stroke of a 4-stroke engine, fuel is injected into the cylinder. Since the piston is near the top of its stroke, the air in the cylinder is compressed (squeezed). Depending on this compression, the gas explodes at a certain rate.
Gasoline's octane rating describes the compression the gas explodes best at. High compression engines, which usually have more horsepower, run best on higher octane gas.
You cannot increase the horsepower of an engine designed to run on 87 octane by putting a higher octance gas in the tank. It just doesn't work.
2006-08-27 06:02:58 · answer #3 · answered by szydkids 5 · 0⤊ 0⤋
Octane is an eight-carbon hydrocarbon with 18 hydrogens. No othe relements.
If you mean octane as in octane rating of gasoline, it is the anti-knock efficiency of a fuel compared to pure iso-octane. Iso-octane is an octane, but with branched carbon chains, and it is arbitrarily assigned an octane rating of 100.
2006-08-27 05:56:19 · answer #4 · answered by dollhaus 7 · 0⤊ 0⤋
octane is the property in gas that makes it harder to burn, the higher the octane the harder to burn the fuel is. the reason for this is that some people hot rod their cars and give them higher compression ratios, then the heat from the compression can ignite the fuel if it is low octane, therefore they use the higher octane so the fuel will be ignited by the spark plug.
2006-08-27 05:55:06 · answer #5 · answered by native 6 · 1⤊ 0⤋
In laymans terms, the speed at which the fuel burns. Additives change the speed the fuel burns at. This is usefull so that it does not burn too fast, expending all its energy too quickly for the engine to operate at peak power output.
2006-08-27 06:00:56 · answer #6 · answered by Anonymous · 0⤊ 0⤋
I would have added more but Mr.Native and Mr.Starreply have already apprised you enough which is suffice and satisfactory.
2006-08-27 06:18:27 · answer #7 · answered by shri 6 · 0⤊ 0⤋