In order to study the degradation characteristics of special and nonspecific motor oil, two experimental vehicles carried out eight road tests with four types of oils, which two types of oils were special oils for its engines recommended by OEM (original equipment manufacturer) and the other two types of nonspecific oil were bought from market. Total acid number, oxidation stability, oxidation, nitration and sulfation values of experimental oils were analysed. The interpolation method and Euclidean distance were used to evaluate the similarity of change curves of oil properties. The results show that the oxidation onset temperature had good similarity both in special oils and nonspecific oils. The sulfation value of nonspecific oils had highest change rate of Euclidean distance. The change rate of Euclidean distance of two special oils were less than 8.48%, which had more stability than that of the nonspecific oils. This work can serve as a reference for end users to select motor oils and oil developers to improve the oil stability.

中文翻译：

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特种和非特种机油的综合降解稳定性研究

为了研究特殊和非特殊机油的降解特性，两辆实验车辆用四种类型的油进行了八次路试，其中两种油是OEM（原始设备制造商）推荐的发动机专用油，另一种是从市场上购买了两种非特异性油。分析了实验油的总酸值，氧化稳定性，氧化，硝化和硫酸化值。用插值法和欧氏距离评价油性变化曲线的相似性。结果表明，在特殊油和非特殊油中，氧化起始温度都具有良好的相似性。非特异性油的硫酸化值具有最高的欧几里得距离变化率。两种特殊油的欧几里得距离的变化率小于8.48％，比非特殊油具有更高的稳定性。这项工作可以为最终用户选择机油和机油开发商以提高机油稳定性提供参考。