Important notice: Website update - 28th of January 2025

We're merging our website with our main site to offer a more streamlined experience. To make the switch smooth, this website undergoing maintenance and will be unavailable on the 28th of January 2025. This means you won't be able to purchase publications. Don't worry, everything will be available on the new site by the end of the day. To avoid any hiccups, we recommend holding off on purchases until then. Thank you for your patience, and see you on the new site soon!

IP 237: Petroleum products - Determination of knock characteristics of motor fuels - Research method copy

Document options


EI Technical Partners get free access to publications. You will need to Login or Register here

  • Method adopted/last revised:
  • Method reapproved: 2019
  • REF/ISBN:
  • Status: Current
  • First printed in STM books:

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.

Members Benefits

Are you an EI Member? If yes, register/log in now to ensure you receive free access or discounts to EI publications.

If you are not a Member, why not join today and receive all of the benefits of EI Membership? EI Members are entitled to a 25% discount on most EI publications.