Abstract: To evaluate the measurement uncertainty of the closed-cup flash point of automotive diesel in plateau environments, this study addresses the requirements for detecting the closed-cup flash point of automotive diesel under plateau conditions. Based on experimental equipment using a fully automatic closed-cup flash point apparatus, this paper comprehensively analyzes the components of uncertainty sources during the flash point measurement process, quantifies the degree of influence of each factor on the measurement results, and derives the combined uncertainty and expanded uncertainty values through mathematical modeling. According to the analysis, the closed-cup flash point measurement result for diesel is (63.5±0.4) ℃. The study finds that during the uncertainty evaluation process, the uncertainty component of repeatability measurements is the largest, serving as the primary source affecting flash point determination results in plateau environments. It has a significant impact on the accuracy of measurement results and should be given focused attention during the testing process.

Key words: plateau environment; automotive diesel; closed flash point; measurement uncertainty

摘要： 为评定高原环境下车用柴油闭口闪点的测量不确定度，针对高原环境下车用柴油的闭 口闪点检测需求，文章基于全自动闭口闪点仪实验设备，全面解析闪点测定过程中不确定度 来源的构成要素，量化各因素对测量结果的影响程度，并通过数学模型推导综合不确定度及 扩展不确定度值。经分析，柴油闭口闪点测量结果为（63.5±0.4）℃。研究发现，不确定度评 定过程中重复性测量的不确定度分量最大，是高原环境下车用柴油闭口闪点测定过程中，影 响闪点测定结果的主要来源，对测量结果的准确性有显著影响，在检测过程中应给予重点关注。

关键词: 高原环境；车用柴油；闭口闪点；测量不确定度