1.1 本试验方法包括监测汽油和天然气发动机机油以及其他类型润滑剂中的硝化作用，其中硝化副产物可能是由于燃烧过程或硝化化合物的其他形成途径而形成的。 1.2 本试验方法使用FT-IR光谱法监测正常机械操作导致的在用石油和碳氢化合物润滑剂中硝化副产物的积累。由于废气再循环或漏气，燃烧副产物与机油发生反应，汽油和天然气发动机机油中的硝化水平升高。本试验方法设计为一种快速、简单的光谱检查，用于监测在用石油和碳氢化合物润滑剂中的硝化情况，目的是通过测量油中的硝化水平来帮助诊断机器的操作条件。 1.3 实践中描述了用于测量在用油和润滑剂样品中硝化作用的FT-IR光谱数据的采集 D7418号 在该测试方法中，给出了使用直接趋势分析和差分（光谱减法）趋势分析的硝化测量和数据解释参数。 1.4 本试验方法基于与在用石油和碳氢化合物润滑剂中硝化相关的光谱变化趋势。对于直接趋势分析，直接从吸收光谱中记录数值，并以每0.1倍100*吸光度为单位进行报告 mm路径长度（或每厘米等效吸光度单位）。对于差异趋势分析，从差异光谱中记录数值（从在用机油的光谱中减去参考机油的光谱得到的光谱），并以100*吸光度/0为单位进行报告。 1 mm路径长度（或每厘米等效吸光度单位）。警告或警报限值可以根据单个测量的固定最大值设置，或者也可以根据测量的响应变化率设置 ( 1. ) . 2. 无论哪种情况，都应通过统计分析、相同或类似设备的历史记录、循环试验或其他方法以及硝化变化与设备性能的相关性来确定此类维护行动限制。 注1: 本试验方法的目的不是为任何机械建立或建议正常、警告、警告或警戒限值。应结合机械制造商和维护小组的建议和指导，确定此类限制。 1.5 本试验方法适用于石油和碳氢化合物润滑剂，不适用于酯- 基础油，包括多元醇酯或磷酸酯。 1.6 以国际单位表示的数值视为标准值。本标准不包括其他计量单位。 1.6.1 例外情况- 波数单位为厘米 -1 . 1.7 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 1.8 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 当机油与发动机燃烧过程中形成的气态硝酸盐反应时，可能会产生和积累多种硝化化合物。这些硝化产物可能会增加油的粘度、酸度和不溶物，从而导致卡环和过滤器堵塞。因此，硝化产物的监测是确定整体机械健康状况的一个重要参数，应结合原子发射（AE）和用于磨损金属分析的原子吸收（AA）光谱等其他测试的数据来考虑（测试方法 D5185型 )物理性能试验（试验方法 D445号 和 D2896型 )和其他FT-IR油氧化分析方法（试验方法 D7414号 )，硫酸盐副产品（试验方法 D7415号 )和添加剂消耗（试验方法 D7412号 )它还评估了石油状况的要素 ( 1- 6. ) .

1.1 This test method covers monitoring nitration in gasoline and natural gas engine oils as well as in other types of lubricants where nitration by-products may form due to the combustion process or other routes of formation of nitration compounds. 1.2 This test method uses FT-IR spectroscopy for monitoring build-up of nitration by-products in in-service petroleum and hydrocarbon-based lubricants as a result of normal machinery operation. Nitration levels in gasoline and natural gas engine oils rise as combustion by-products react with the oil as a result of exhaust gas recirculation or a blow-by. This test method is designed as a fast, simple spectroscopic check for monitoring of nitration in in-service petroleum and hydrocarbon-based lubricants with the objective of helping diagnose the operational condition of the machine based on measuring the level of nitration in the oil. 1.3 Acquisition of FT-IR spectral data for measuring nitration in in-service oil and lubricant samples is described in Practice D7418 . In this test method, measurement and data interpretation parameters for nitration using both direct trend analysis and differential (spectral subtraction) trend analysis are presented. 1.4 This test method is based on trending of spectral changes associated with nitration in in-service petroleum and hydrocarbon-based lubricants. For direct trend analysis, values are recorded directly from absorption spectra and reported in units of 100*absorbance per 0.1 mm pathlength (or equivalently absorbance units per centimetre). For differential trend analysis, values are recorded from the differential spectra (spectrum obtained by subtraction of the spectrum of the reference oil from that of the in-service oil) and reported in units of 100*absorbance per 0.1 mm pathlength (or equivalently absorbance units per centimetre). Warnings or alarm limits can be set on the basis of a fixed maximum value for a single measurement or, alternatively, can be based on a rate of change of the response measured ( 1 ) . 2 In either case, such maintenance action limits should be determined through statistical analysis, history of the same or similar equipment, round robin tests or other methods in conjunction with the correlation of nitration changes to equipment performance. Note 1: It is not the intent of this test method to establish or recommend normal, cautionary, warning or alert limits for any machinery. Such limits should be established in conjunction with advice and guidance from the machinery manufacturer and maintenance group. 1.5 This test method is for petroleum and hydrocarbon-based lubricants and is not applicable for ester-based oils, including polyol esters or phosphate esters. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6.1 Exception— The unit for wave numbers is cm -1 . 1.7 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. 1.8 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 There is a wide variety of nitration compounds that may be produced and accumulate when oils react with gaseous nitrates formed during the engine combustion process. These nitration products may increase the viscosity, acidity and insolubles in the oil, which may lead to ring sticking and filter plugging. Monitoring of nitration products is therefore an important parameter in determining overall machinery health and should be considered in conjunction with data from other tests such as atomic emission (AE) and atomic absorption (AA) spectroscopy for wear metal analysis (Test Method D5185 ), physical property tests (Test Methods D445 and D2896 ), and other FT-IR oil analysis methods for oxidation (Test Method D7414 ), sulfate by-products (Test Method D7415 ), and additive depletion (Test Method D7412 ), which also assess elements of the oil’s condition ( 1- 6 ) .