Derived Cetane Numbers (DCNs) of engine lubricating oil/multicomponent 95 Research Octane Number (RON) gasoline surrogate mixtures were measured in an Ignition Quality Tester (IQT). Measurements separately assess the effects of calcium- and magnesium-based detergent additive fraction, oil viscosity, oil degradation, and base oil classification on mixture ignition propensity at conditions with relevance to low speed pre-ignition (LSPI) in gasoline engines. Testing of 0–25% (by mass) oil blended into a six-component surrogate mixture representing an unleaded “average” European gasoline blend is used to determine sensitivity of DCN responses to variations in the properties. With one exception, mixture DCNs were found to increase with lubricating oil content. Despite variation in calcium and magnesium concentrations, DCN responses for all oil blends indicate no statistically significant effect of either calcium or magnesium. Similarly, neither aging of nor peroxide addition to the oil yields significant DCN changes compared to untreated oils. However, a distinct response is found for variations in the base lubricant chemical structural properties. At 25% oil blending with gasoline surrogate, the measured DCNs (RONs) of different group base oils range from 19.6 (95.7) to 42.1 (46.2). The DCN increases with increasing base oil API Group Number (I through IV); however, mixture DCN was found to decrease for a 25% blend of Group V-B with the gasoline surrogate. Using quantitative ¹H NMR, the Group Number trend is interpreted to be a consequence of linear vs. branched character of the paraffinic base oil composition. Taken together, the present results indicate that at ASTM D6890 DCN test conditions, there is no significant ignition effect attributable to reasonable variations in the lubricant's calcium or magnesium content, viscosity, or degree of degradation. Instead, the isomeric character of the paraffinic base oil appears to be most significant in controlling lubricant autoignition properties relative to those of gasolines.

发动机润滑油/多元油的十六烷值（DCN）的测定95研究辛烷值（RON）汽油替代混合物在点火质量测试仪（IQT）中进行了测量。在与汽油发动机低速提前点火（LSPI）相关的条件下，测量分别评估了钙基和镁基清洁剂添加剂分数，机油粘度，机油降解和基础油分类对混合物着火倾向的影响。对代表无铅“平均”欧洲汽油混合物的六组分替代混合物中掺混的0–25％（质量）油进行测试，以确定DCN对性能变化的敏感性。除一个例外，发现混合DCN随着润滑油含量的增加而增加。尽管钙和镁的浓度存在差异，所有油混合物的DCN响应均表明，钙或镁的作用均无统计学意义。类似地，与未处理的油相比，未老化或未向油中添加过氧化物也不会产生显着的DCN变化。然而，对于基础润滑剂化学结构性质的变化，发现了明显的响应。在25％的油与汽油替代物混合时，不同组基础油的DCN（RON）测得范围为19.6（95.7）至42.1（46.2）。DCN随着基础油API组号（I至IV）的增加而增加；但是，发现VB组与汽油替代品的混合比例为25％时，混合物DCN减少。使用定量 与未处理的油相比，油的老化或过氧化物的添加都不会产生明显的DCN变化。然而，对于基础润滑剂化学结构性质的变化，发现了明显的响应。在25％的油与汽油替代物混合时，不同组基础油的DCN（RON）测得范围为19.6（95.7）至42.1（46.2）。DCN随着基础油API组号（I至IV）的增加而增加；但是，发现VB组与汽油替代品的混合比例为25％时，混合物DCN减少。使用定量 与未处理的油相比，油的老化或过氧化物的添加都不会产生明显的DCN变化。然而，对于基础润滑剂化学结构性质的变化，发现了明显的响应。在25％的油与汽油替代物混合时，不同组基础油的DCN（RON）测得范围为19.6（95.7）至42.1（46.2）。DCN随着基础油API组号（I至IV）的增加而增加；但是，发现VB组与汽油替代品的混合比例为25％时，混合物DCN减少。使用定量 DCN随着基础油API组号（I至IV）的增加而增加；但是，发现VB组与汽油替代品的混合比例为25％时，混合物DCN减少。使用定量 DCN随着基础油API组号（I至IV）的增加而增加；但是，发现VB组与汽油替代品的混合比例为25％时，混合物DCN减少。使用定量¹ H NMR中，基团数趋势被解释为链烷烃基油组合物的线性与支化特征的结果。综上所述，目前的结果表明，在ASTM D6890 DCN测试条件下，由于润滑剂的钙或镁含量，粘度或降解程度发生合理变化，因此没有明显的起火作用。取而代之的是，石蜡基油的异构体特征在控制润滑剂自燃性能方面相对于汽油最重要。