Engine Oils in the Field: A Comprehensive Chemical Assessment of Engine Oil Degradation in a Passenger Car
Engine Oils in the Field: A Comprehensive Chemical Assessment of Engine Oil Degradation in a Passenger Car
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DOI：
10.1007/s11249-019-1182-7
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发表时间：
2019-09-01
影响因子：
3.2
通讯作者：
Frauscher, Marcella
中科院分区：
文献类型：
--
作者：
Doerr, Nicole;Agocs, Adam;Frauscher, Marcella
为了了解内燃机中的油降解，特别是二烷基二硫代磷酸锌（ZDDP）的劣化及其对以铁含量表示的磨损的影响，对乘用车进行了现场测试，该测试覆盖了19，800 km的距离并且代表了整个换油间隔。采用常规分析方法和先进分析方法相结合的方法，对涡轮增压汽油机使用的SAE 5 W-30发动机油进行了状态监测。从废油中收集的常规数据揭示了添加剂（抗氧化剂、碱储备、ZDDP）、油降解产物（氧化、硝化、硫酸化、酸）和污染物（水、烟灰、磨损、燃料稀释）的进展。包括高分辨率质谱法，以确定ZDDP添加剂化合物和它们的命运在现场测试，以及它们与磨损形成的相关性。作为主要ZDDP化合物的二烷基二硫代磷酸盐迅速降解，在6000 km后不再检测到。作为中间体ZDDP降解产物的二烷基硫代磷酸盐在最初的6000 km内形成并基本耗尽。作为有机和无机ZDDP降解产物的二烷基磷酸盐、磷酸和硫酸在早期产生，并在田间试验结束时达到高水平。完整的ZDDP及其降解产物，特别是磷酸和硫酸的存在与石油的铁含量相关。只要完整的ZDDP可用于摩擦膜形成，磨损基本上保持在低水平。ZDDP的缺乏沿着ZDDP形成无机酸导致磨损率增加四倍。
For the understanding of oil degradation in a combustion engine, in particular zinc dialkyl dithiophosphate (ZDDP) deterioration and its impact on wear expressed as iron content, a field test with a passenger car was carried out, which covered a distance of 19,800 km and represented an entire oil change interval. Condition monitoring of the SAE 5W-30 engine oil usedin theturbocharged petrol engine combined the use of conventional and advanced analytical methods. The conventional data collected from the used oils revealed the progress of additives (antioxidants, base reserve, ZDDP), oil degradation products (oxidation, nitration, sulfation, acids), and contaminations (water, soot, wear, fuel dilution). High-resolution mass spectrometry was included to identify ZDDP additive compounds and their fate during the field test as well as their correlation with wear formation. Dialkyl dithiophosphates as the main ZDDP compounds were rapidly degraded and no longer detected after 6000 km. Dialkyl thiophosphate as intermediate ZDDP degradation product was formed and largely depleted within the first 6000 km. Dialkyl phosphates, phosphoricacid, and sulfuric acid as organic and inorganic ZDDP degradation products were generated early and reached high levels at the end of the field test. The presence of intact ZDDP and its degradation products, notably phosphoric and sulfuric acid, correlated with the oil's iron content. Wear largely remained at low level as long as intact ZDDP was available for tribofilm formation. The lack of ZDDP along with the formation of inorganic acids from ZDDP resulted in an increase in the wear rate by a factor of four.