Abstract A full size ceramic substrate was successfully prepared using a robocasting 3D printer and tested as a methane oxidation catalyst in the after treatment system (ATS) of a heavy-duty diesel engine, converted to co-combust (dual fuel) with natural gas (NG). The 3D printed substrate performance exceeded that of a commercially sourced straight-channelled DOC over most working conditions, despite the 3D printed structure having a lower precious group metal (PGM) loading and channels per square inch (CPSI) density. At moderate and high inlet temperatures, where the reaction rate is limited by internal and external mass transfer, the enhanced catalytic activity of the 3D printed substrate is attributed to the generation of internal turbulence, which increases oxidation rates of methane (CH4) and non-methane hydrocarbons (NMHC). In contrast, there is relatively little difference between the catalytic activity of the 3D and straight-channelled substrates at low temperatures (e.g. cold start up), where the reaction is kinetically controlled and the additional turbulence/mass transfer of the 3D printed complex structure did not measurably alter the catalytic converter performance. Computational fluid dynamics (CFD) confirmed the increased turbulence within the channels of the 3D printed structure. We also report the effects of NG substitution on the fuel combustion efficiency under different engine load settings. The findings provide proof of concept evidence that 3D printing is a suitable means of designing a catalytic converter prototype with higher reaction activity than a conventionally extruded structure. This has significant implications for the design and potential mass production of new catalytic converters with enhanced efficiencies.

中文翻译：

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用于双燃料重型发动机排放控制的工业规模 3D 打印催化转化器

摘要 使用机器人铸造 3D 打印机成功制备了全尺寸陶瓷基板，并在重型柴油发动机的后处理系统 (ATS) 中作为甲烷氧化催化剂进行了测试，转化为与天然气混合燃烧（双燃料）。 NG）。尽管 3D 打印结构具有较低的贵族金属 (PGM) 负载和每平方英寸通道 (CPSI) 密度，但 3D 打印基板的性能在大多数工作条件下都超过了商业采购的直通道 DOC。在中等和高入口温度下，反应速率受内部和外部传质限制，3D 打印基材的催化活性增强归因于内部湍流的产生，这增加了甲烷 (CH4) 和非甲烷碳氢化合物 (NMHC)。相比之下，在低温（例如冷启动）下，3D 和直通道底物的催化活性之间的差异相对较小，其中反应是动力学控制的，并且 3D 打印的复杂结构的额外湍流/质量转移没有显着改变催化转化器的性能。计算流体动力学 (CFD) 证实了 3D 打印结构通道内的湍流增加。我们还报告了在不同发动机负载设置下天然气替代对燃料燃烧效率的影响。这些发现提供了概念证据，证明 3D 打印是设计具有比传统挤压结构更高反应活性的催化转化器原型的合适手段。