Indicator of capacity for a product to resist high pressures without spontaneous combustion occurring also known as resistance to knocking. When the numbers were first developed, the researchers found that normal heptane (a hydrocarbon) had almost no ability to resist knocking so they gave it an octane number of zero. Then they found that isooctane (also a hydrocarbon) was very resistant to knocking so they gave it the octane number of 100. To measure a particular sample of gasoline they discovered when it began to create detonation. Then they mixed isooctane to heptane to find out what percentage of isooctane created the same results as the sample of gasoline. There are two methods for determining the octane number depending upon operating conditions. The Research Octane Number (RON) is obtained when conditions are somewhat mild. The Motor Octane Number (MON) is obtained when conditions are somewhat severe and give a much lower number than the RON.
Measure of the anti-knock qualities of a gasoline fuel.
A term (Motor Octane Number) devised by Graham Edgar in 1926 to measure the anti-knock quality of gasoline. The octane number of a given fuel is the percentage of iso-octane (octane number: 100) in a blend with n-heptane (octane number: 0) with the same anti-knock properties as a sample of the motor gasoline being tested. A high octane fuel has better anti-knock properties than one with a low number. A similar but improved method (Research Octane Number) was developed in the late 1930's.
A performance rating used to classify motor fuels by grading the relative antiknock properties of various gasolines. A high-octane fuel has better antiknock properties than one with a low number.
A rating, which is the average of the motor octane and research octane of a fuel sample, used to indicate gasoline's anti-knock performance in motor vehicle engines. The higher the octane number, the higher the resistance to engine knock.
The rating number that indicates a gasoline's ability to resist knocking.
A measure of the antiknock quality of gasoline.
A measure of the resistance of gasoline to pre-ignite or knock when burned in an internal combustion engine.
Measure of anti-knock properties of gasoline. The higher the octane number, the greater the resistance to knock. Measured in the laboratory by the Research Method (RON) and the more severe Motor Method (MON). Octane numbers posted on service station pumps are average of the two ratings - (RON + MON)/2.
a measure of the antiknock properties of gasoline
Measurement of the resistance of gasoline to explosive preignition, also known as knocking. Reference is to 2,2,4-trimethylpentane (isooctane) mixtures with n-heptane, with pure isooctane defined as 100.
A measure of a fuel's ability to prevent detonation in a spark ignition engine. Measured in a standard single-cylinder, variable-compression-ratio engine by comparison with primary reference fuels. Under mild conditions, the engine measures Research Octane Number (RON); under severe conditions Motor Octane Number (MON). Where the law requires posting of octane numbers on dispensing pumps, the Antiknock Index (AKI) is used. This is the arithmetic average of RON and MON, (R + M)/2. It approximates the Road Octane Number, which is a measure of how an "average" car responds to the fuel.
An arbitrary value denoting the antiknock rating of a gasoline.
A number that indicates how smoothly a gasoline burns.
The percentage of iso-octane in an iso-octane/heptane mixture that gives the same engine performance of the fuel.
A number used to indicate gasoline's antiknock performance in motor vehicle engines. The two recognized laboratory engine test methods for determining the antiknock rating, i.e., octane rating of gasoline, are the Research method and the Motor method. To provide a single number as guidance to the consumer, the antiknock index (R + M) /2, which is the average of the Research and Motor octane numbers, was developed.
A term numerically indicating the relative antiknock value of a gasoline. For octane numbers 100 or below, it is based upon a comparison with the reference fuels isooctane (100 octane number) and n-heptane (0 octane number). The octane number of an unknown fuel is the percent by volume of isooctane with n-heptane which matches the unknown fuel in knocking tendencies under a specified set of conditions. Above 100, the octane number of a fuel is based on the engine rating, in terms of milliliters of tetraethyllead in isooctane which matches that of the unknown fuel.
The number representing the average blend of iso-octane with an index of 100, and other hydrocarbons with an index of 0, usually between 87 and 92.
A measure of the properties to resist pre-ignition ("knock") when burned in an internal combustion engine. The higher the number shows the more anti-knock quality.