The processes of degradation of engine oils operated in passenger cars of a uniform fleet of 25 vehicles were analyzed for oxidation content using infrared (IR) spectroscopy. As part of the experiment, the changes in engine oils occurring during actual operation (under conditions which can be described as “harsh”, i.e., short distance driving, frequent starting of the engine, and extended engine idling) have been observed. An evaluation of the Fourier transform infrared spectroscopy (FTIR) spectrum of an engine oil sample was presented. The infrared spectra of both fresh and used oils were recorded with the Thermo Nicolett IS5. The tests were conducted according to the Appendix A2 of ASTM 2412. For the used engine oil differentiation process, FTIR spectra were analyzed in the regions of 1,700–2,000 cm⁻¹ and 3,600-3,700 cm⁻¹. The FTIR spectrometry is demonstrated to be effective for the analysis and monitoring of processes of oxidation and shown to provide rapid and accurate information relating to the aging process of engine oils. The results may facilitate decision-making regarding the service life of engine oils. The achieved dependencies can make it possible to upgrade the sensor assembly consisting of an FTIR source.

中文翻译：

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FTIR分析和监测在类似驾驶条件下运行的废合成油

使用红外（IR）光谱分析了25辆均匀车队的乘用车中使用的机油的降解过程的氧化含量。作为实验的一部分，已经观察到在实际操作过程中（在可以描述为“严酷”的条件下，即短距离驾驶，频繁启动发动机和长时间怠速运转）发生的机油变化。提出了对机油样品的傅立叶变换红外光谱（FTIR）光谱的评估。用Thermo Nicolett IS5记录新鲜和用过的油的红外光谱。根据ASTM 2412的附录A2进行了测试。对于所用的机油鉴别过程，在1,700–2,000 cm ^-1的区域内分析了FTIR光谱。和3,600-3,700 cm ^-1。FTIR光谱被证明可有效地分析和监测氧化过程，并能提供与机油老化过程有关的快速准确信息。结果可能有助于做出有关机油使用寿命的决策。所获得的依赖性可以升级包含FTIR源的传感器组件。