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An octane rating, or octane number, is a standard measure of a fuel's ability to withstand compression in an internal combustion engine without causing engine knocking.The higher the octane number, the more compression the fuel can withstand before detonating.
N-octane is the octane isomer that has the longest carbon skeleton. Unlike its constitutional isomers, it has a very low knock resistance. The octane isomer, iso-octane, is used as one of the standards for octane ratings. It has a rating of 100 by definition. The octane isomer 2,3,3-Trimethylpentane has an octane rating exceeding 100.
In the United States and Canada, octane ratings are in AKI, commonly shown as "(R+M)/2". All states require gas pumps to be labeled with the correct octane level and nearly all states do regular testing to make sure gas stations are in compliance. A minimum 82 octane fuel is recommended for most vehicles produced since 1984.
High levels of benzene have been detected near stations across urban, suburban, and rural environments, though the causes (such as road traffic or congestion) can vary by location. [ 17 ] Gas station attendants have suffered adverse health consequences depending on the type of fuel used, exposure to vehicle exhaust, and types of personal ...
Octane rating is measured relative to a mixture of 2,2,4-trimethylpentane (an isomer of octane) and n-heptane. There are different conventions for expressing octane ratings, so the same physical fuel may have several different octane ratings based on the measure used. One of the best known is the research octane number (RON).
Given a fire of sufficient duration and intensity, the pressure being generated by the boiling and expanding gas can exceed the ability of the valve to vent the excess. Alternatively, if, due to continued venting, the liquid level drops below the area being heated, the tank structure can be overheated and subsequently weakened in that area.
In the video above, Robb Report senior editor Justin Fenner breaks down the levels of fragrance, from light, breezy eau de toilette to intense, long-lasting extrait de parfum. (We’re leaving out ...
the use of a fuel with high octane rating, which increases the combustion temperature of the fuel and reduces the proclivity to detonate; enriching the air–fuel ratio which alters the chemical reactions during combustion, reduces the combustion temperature and increases the margin to detonation; reducing peak cylinder pressure