1.1 本试验方法包括通过直接比较火花点火发动机燃料流样品的爆震额定值或δ辛烷值与比较参考燃料的爆震额定值或δ辛烷值的差异进行在线定量测定。 1.2 本试验方法涵盖了使用测量的δ辛烷值和比较参考燃料的辛烷值获得辛烷值的方法。 1.3 对比参考燃料要求与待分析的流样成分基本相同，可以是称为标准燃料的二次燃料或称为原型燃料的三次燃料。 1.4 该测试方法利用爆震测试装置/自动分析仪系统，该系统采用计算机控制标准化单缸、四冲程循环、可变压缩比、化油器、CFR发动机以及使用任一测试方法的适当辅助设备 D2699 研究方法或测试方法 D2700 电机方法操作条件。 1.4.1 爆震测量基于两种燃料在产生该燃料最大爆震强度的燃料空气比下的运行。 1.4.2 当在相同压缩比下比较燃料时，对爆震强度的测量差异进行缩放，以提供来自比较参考燃料的流样品的正或负δ辛烷值。 1.4.3 当在相同的爆震强度下比较燃料时，根据适当的指导表按比例测量压缩比差异，以提供来自比较参考燃料的流样品的正或负δ辛烷值。 1.5 本试验方法仅限于使用研究法或电机法条件测试78至102辛烷值火花点火发动机燃料。 1.6 流样品和适用的比较参考燃料之间的辛烷值差是自相关的- 受到标准和原型燃料规范的限制。 1.7 提供了标准和原型燃料的选择、制备、储存和分配规范。还包含了确定标准燃料和原型燃料适当分配辛烷值的详细程序。 1.8 工作条件值以国际单位制表示，并被视为标准值。括号中的值是历史英寸-磅单位。标准CFR发动机测量值继续以英寸-磅单位表示，这只是因为为该设备创建了大量且昂贵的工具。 1.9 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 有关更具体的警告声明，请参阅第节 8. 和 附件A1 . 1.10 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 δ辛烷值（ΔO.N.）测量可以量化直列混合火花点火发动机燃料或工艺流材料辛烷值与所需辛烷值的差异，以帮助优化搅拌器设施或炼油厂工艺装置的控制。 5.2 ΔO.N.测量值与比较参考燃料O.N.相加，提供当前在线混合火花点火发动机燃料或工艺流材料的研究或发动机辛烷值。 5.3 根据实践，通过使用重复ΔO.N.结果的累积流量比例平均值 D6624 ，平均辛烷值可分配给一批或一批在线混合火花点火发动机燃料。

1.1 This test method covers the quantitative online determination by direct comparison of the difference in knock rating or delta octane number of a stream sample of spark-ignition engine fuel from that of a comparison reference fuel. 1.2 This test method covers the methodology for obtaining an octane number using the measured delta octane number and the octane number of the comparison reference fuel. 1.3 The comparison reference fuel is required to be of essentially the same composition as the stream sample to be analyzed and can be a secondary fuel termed standard fuel or a tertiary fuel termed prototype fuel. 1.4 The test method utilizes a knock testing unit/automated analyzer system that incorporates computer control of a standardized single-cylinder, four-stroke cycle, variable compression ratio, carbureted, CFR engine with appropriate auxiliary equipment using either Test Method D2699 Research method or Test Method D2700 Motor method operating conditions. 1.4.1 Knock measurements are based on operation of both fuels at the fuel-air ratio that produces maximum knock intensity for that fuel. 1.4.2 Measured differences in knock intensity are scaled to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same compression ratio. 1.4.3 Measured differences in compression ratio are scaled from the appropriate guide table to provide a positive or negative delta octane number of the stream sample from the comparison reference fuel when the fuels are compared at the same knock intensity. 1.5 This test method is limited to testing 78 to 102 octane number spark-ignition engine fuels using either research or motor method conditions. 1.6 The octane number difference between the stream sample and the applicable comparison reference fuel is self-limiting by specifications imposed upon the standard and prototype fuels. 1.7 Specifications for selection, preparation, storage, and dispensing of standard and prototype fuels are provided. Detailed procedures for determination of an appropriate assigned octane number for both standard and prototype fuels are also incorporated. 1.8 The values of operating conditions are stated in SI units and are considered standard. The values in parentheses are historical inch-pound units. The standardized CFR engine measurements continue to be expressed in inch-pound units only because of the extensive and expensive tooling that has been created for this equipment. 1.9 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For more specific warning statements, see Section 8 and Annex A1 . 1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 The delta octane number (ΔO.N.) measure can quantify the difference of in-line blended spark-ignition engine fuel or process stream material octane number to a desired octane number to aid in optimizing control of blender facilities or refinery process units. 5.2 The ΔO.N. measure, summed with a comparison reference fuels O.N. provides either research or motor octane number value of the current in-line blended spark-ignition engine fuel or process stream material. 5.3 Through the use of cumulative flow-proportioned averaging of the repetitive ΔO.N. results, in accordance with Practice D6624 , an average octane number can be assigned to a tender or batch of in-line blended spark-ignition engine fuel.