Spatially Resolved Molecular Compositions of Insoluble Multilayer Deposits Responsible for Increased Pollution from Internal Combustion Engines
Spatially Resolved Molecular Compositions of Insoluble Multilayer Deposits Responsible for Increased Pollution from Internal Combustion Engines
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DOI：
10.1021/acsami.0c14532
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发表时间：
2020-11-11
影响因子：
9.5
通讯作者：
Scurr, David J.
中科院分区：
文献类型：
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作者：
Edney, Max K.;Lamb, Joseph S.;Scurr, David J.
内燃机在世界范围内的各种应用中大量使用。随着社会转向脱碳能源系统，实现最高效的运行是改善空气质量的关键。内燃机部件（包括喷油器和过滤器）内形成的不溶性沉积物会对二氧化碳和污染物排放产生负面影响。了解这些复杂材料的组成，起源和形成机制将是缓解它们的关键，然而，以前的尝试只提供了非诊断性的化学分配和有限的知识。在这里，我们发现的身份和空间分布的分子物种从汽油直接喷射器，柴油喷射器，和过滤器存款原位使用新的二次离子质谱联用和国家的最先进的轨道阱质量分析仪（3D OrbiSIMS）和元素分析。通过高质量分辨能力和串联MS，我们明确地揭示了包括烷基苄基磺酸盐在内的物质的身份、分布和来源，并提供了存款形成机制的证据，包括在汽油存款表面形成较长链的磺酸盐以及芳构化以形成高达C66 H20的多环芳烃，这在该存款的较低深度中普遍存在。无机盐对柴油喷射器整个深度的存款有很大贡献，表明在多个加油循环中受到污染。研究结果将使几种策略，以减轻这些不溶性材料，如实施更严格的全球燃料规格，修改添加剂与不利的反应，并合成新的燃料添加剂，以溶解沉积物在发动机中，从而导致污染较少的车辆。
Internal combustion engines are used heavily in diverse applications worldwide. Achieving the most efficient operation is key to improving air quality as society moves to a decarbonized energy system. Insoluble deposits that form within internal combustion engine components including fuel injectors and filters negatively impact CO2 and pollutant emissions. Understanding the composition, origins, and formation mechanisms of these complex materials will be key to their mitigation however, previous attempts only afforded nondiagnostic chemical assignments and limited knowledge toward this. Here, we uncover the identity and spatial distribution of molecular species from a gasoline direct injector, diesel injector, and filter deposit in situ using a new hyphenation of secondary ion mass spectrometry and the state-of-the-art Orbitrap mass analyzer (3D OrbiSIMS) and elemental analysis. Through a high mass resolving power and tandem MS we unambiguously uncovered the identity, distribution, and origin of species including alkylbenzyl sulfonates and provide evidence of deposit formation mechanisms including formation of longer chain sulfonates at the gasoline deposit's surface as well as aromatization to form polycyclic aromatic hydrocarbons up to C66H20, which were prevalent in the lower depth of this deposit. Inorganic salts contributed significantly to the diesel injector deposit throughout its depth, suggesting contamination over multiple fueling cycles. Findings will enable several strategies to mitigate these insoluble materials such as implementing stricter worldwide fuel specifications, modifying additives with adverse reactivity, and synthesizing new fuel additives to solubilize deposits in the engine, thereby leading to less polluting vehicles.