ASTM D2699 - 13b

    Standard Test Method for Research Octane Number of Spark-Ignition Engine Fuel

    Active Standard ASTM D2699 | Developed by Subcommittee: D02.01

    Book of Standards Volume: 05.05


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    Significance and Use

    5.1 Research O.N. correlates with commercial automotive spark-ignition engine antiknock performance under mild conditions of operation.

    5.2 Research O.N. is used by engine manufacturers, petroleum refiners and marketers, and in commerce as a primary specification measurement related to the matching of fuels and engines.

    5.2.1 Empirical correlations that permit calculation of automotive antiknock performance are based on the general equation:

    Equation D2699-13B_1

    Values of k1, k2, and k3 vary with vehicles and vehicle populations and are based on road-O.N. determinations.

    5.2.2 Research O.N., in conjunction with Motor O.N., defines the antiknock index of automotive spark-ignition engine fuels, in accordance with Specification D4814. The antiknock index of a fuel approximates the Road octane ratings for many vehicles, is posted on retail dispensing pumps in the U.S., and is referred to in vehicle manuals.

    Equation D2699-13B_2

    This is more commonly presented as:

    Equation D2699-13B_3

    5.2.3 Research O.N. is also used either alone or in conjunction with other factors to define the Road O.N. capabilities of spark-ignition engine fuels for vehicles operating in areas of the world other than the United States.

    5.3 Research O.N. is used for measuring the antiknock performance of spark-ignition engine fuels that contain oxygenates.

    5.4 Research O.N. is important in relation to the specifications for spark-ignition engine fuels used in stationary and other nonautomotive engine applications.

    1. Scope

    1.1 This laboratory test method covers the quantitative determination of the knock rating of liquid spark-ignition engine fuel in terms of Research O.N., including fuels that contain up to 25 % v/v of ethanol. However, this test method may not be applicable to fuel and fuel components that are primarily oxygenates.2 The sample fuel is tested using a standardized single cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine run in accordance with a defined set of operating conditions. The O.N. scale is defined by the volumetric composition of PRF blends. The sample fuel knock intensity is compared to that of one or more PRF blends. The O.N. of the PRF blend that matches the K.I. of the sample fuel establishes the Research O.N.

    1.2 The O.N. scale covers the range from 0 to 120 octane number but this test method has a working range from 40 to 120 Research O.N. Typical commercial fuels produced for spark-ignition engines rate in the 88 to 101 Research O.N. range. Testing of gasoline blend stocks or other process stream materials can produce ratings at various levels throughout the Research O.N. range.

    1.3 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are the historical inch-pound units. The standardized CFR engine measurements continue to be in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment.

    1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8, 13.4.1, 14.5.1, 15.6.1, Annex A1, A2.2.3.1, A2.2.3.3 (6) and (9), A2.3.5, X3.3.7, X4.2.3.1, X4.3.4.1, X4.3.9.3, X4.3.11.4, and X4.5.1.8.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D1193 Specification for Reagent Water

    D2268 Test Method for Analysis of High-Purity n-Heptane and Isooctane by Capillary Gas Chromatography

    D2360 Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography

    D2700 Test Method for Motor Octane Number of Spark-Ignition Engine Fuel

    D2885 Test Method for Determination of Octane Number of Spark-Ignition Engine Fuels by On-Line Direct Comparison Technique

    D3703 Test Method for Hydroperoxide Number of Aviation Turbine Fuels, Gasoline and Diesel Fuels

    D4057 Practice for Manual Sampling of Petroleum and Petroleum Products

    D4175 Terminology Relating to Petroleum, Petroleum Products, and Lubricants

    D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products

    D4814 Specification for Automotive Spark-Ignition Engine Fuel

    D5842 Practice for Sampling and Handling of Fuels for Volatility Measurement

    D6304 Test Method for Determination of Water in Petroleum Products, Lubricating Oils, and Additives by Coulometric Karl Fischer Titration

    E344 Terminology Relating to Thermometry and Hydrometry

    E456 Terminology Relating to Quality and Statistics

    E542 Practice for Calibration of Laboratory Volumetric Apparatus

    E1064 Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration

    ANSI Standard

    C-39.1 Requirements for Electrical Analog Indicating Instruments


    ICS Code

    ICS Number Code 75.160.20 (Liquid fuels)

    UNSPSC Code

    UNSPSC Code 15101506(Gasoline or Petrol)


    DOI: 10.1520/D2699

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