BS EN ISO 5164:2014

1   Scope This International Standard establishes the rating of liquid spark-ignition engine fuel in terms of an arbitrary scale of octane numbers using a standard single-cylinder, four-stroke cycle, variable compression ratio, carburetted, CFR engine operated at constant speed. Research octane number ( RON ) provides a measure of the knock characteristics of motor fuels in automotive engines under mild conditions of operation. This International Standard is applicable for the entire scale range from 0  RON to 120  RON , but the working range is 40  RON to 120  RON . Typical motor fuel testing is in the range of 88  RON to 101  RON . This International Standard is applicable for oxygenate -containing fuels containing up to 4,0 % ( m / m ) oxygen and for gasoline containing up to 25 %( V/V ) ethanol.

NOTE 1 Although 25 % ( V/V ) of ethanol corresponds to approximately 9 % ( m/m ) oxygen, full applicability of this test method for that oxygen range has only been checked for gasoline type of fuels.

NOTE 2 Work is under way to check the possibility to use the method up to and including 85 %( V/V ) ethanol.

NOTE 3 This International Standard specifies operating conditions in ...