Combination Octane Rating Unit Engine




This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research Octane Number and the Motor Octane Number, including fuels that contain up to 25% v/v of ethanol. The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted engine run in accordance with a defined set of operating conditions.