The energy content of the gasoline is measured by burning all the fuelinside a bomb calorimeter and measuring the temperature increase.The energy available depends on what happens to the water produced from the combustion of the hydrogen. If the water remains as a gas, then it cannot release the heat of vaporisation, thus producing the Nett Calorific Value.If the water were condensed back to the original fuel temperature, then Gross Calorific Value of the fuel, which will be larger, is obtained.The calorific values are fairly constant for families of HCs, which is not surprising, given their fairly consistent carbon:hydrogen ratios. For liquid or gaseous g fuel converted to gaseous products except for the methylbutene2, where only gaseous is reported.Blending Octane Number as reported by API Project 45 using 60 octane base fuel, and the numbers in brackets are Blending Octane Numbers currently used for modern fuels.

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