CAREER: Fuels, Additives and Emissions in Low-Temperature Combustion

减少发动机尾气排放的一种策略是将燃烧控制在低于常规值的温度。低温压燃式发动机代表了一种新的内燃机，可以满足严格和迫在眉睫的燃油经济性要求。工程师通常在燃料中添加添加剂以改善发动机性能。最常用的添加剂含有氮，但燃料结合氮在低温燃烧中的去向却鲜为人知。虽然这些发动机中由含氮添加剂形成的一些最终燃烧副产品可能相对无害，但其他副产品毒性很大，这些有毒副产品的相对产量尚不清楚。这项提议的目标是发现燃料结合氮在先进发动机中的命运。在五年的时间里，PI将结合新的实验、理论和建模技术，为发动机相关条件下含氮添加剂的燃烧副产物提供定量测量和动力学预测。这项研究将为工程师提供工具，以量化添加剂和内燃机运输燃料之间的相互作用，并预测添加剂、燃料或发动机的变化将如何影响排放。此外，这项研究将改善他们对雾霾和相关问题的预测，从而使大气化学家受益。最后，PI将开发一系列教育模块，说明改变燃料结构如何改变其燃烧特性，并将创建动手设计项目，让学生建造不同的燃烧设备。低温压燃式发动机中使用最广泛的燃料添加剂是硝酸乙酯(2EHN)。假设是2EHN中相当大比例的氮以氰化氢和其他剧毒化合物的形式离开钢瓶。为了验证这一假设，将结合激波管实验、电子结构理论和动力学模型研究来量化各种含氮产品，并建立产生它们的反应路径。此外，PI将与阿贡国家实验室的工程师合作开发计算模型，以预测2EHN将如何与现实世界的运输燃料相互作用，如正庚烷、异辛烷和甲苯。低温压燃式发动机中的许多关键通道都是动态控制的，因此这些发动机产生的燃烧副产品与传统的高温发动机不同。对这些途径的了解对于含有氮的燃料添加剂尤为重要。我们对氮化学的大多数理解都局限于超过NOx热极限的高温，或者大气中的低温。这一提议将通过阐明在热NOx阈值以下的含氮物种的氧化和还原的关键化学途径，填补我们对氮化学理解的一个关键空白。

CBET-1553366, GoldsmithOne strategy to reduce the engine exhaust emissions is to control the combustion at a temperature lower than the conventional value. Low-temperature compression-ignition engines represent a new class of internal combustion engines that could meet the stringent and imminent fuel economy requirements. Engineers typically add additives to the fuel to improve the engine performance. The most commonly used additive contains nitrogen, yet the fate of fuel-bound nitrogen in low-temperature combustion is poorly understood. Although some of the ultimate combustion byproducts formed by nitrogen-containing additives in these engines may be comparatively benign, other byproducts are highly toxic, and the relative yield of these toxic byproducts is not known. The goal of this proposal is to discover the fate of fuel-bound nitrogen in advanced engines. Over the course of five years, the PI will combine novel experimental, theoretical, and modeling techniques to provide quantitative measurements and kinetic predictions for the combustion byproducts of nitrogen-containing additives under engine-relevant conditions. This research will provide engineers with the tools to quantify the interactions between additives and transportation fuels in internal combustion engines, and to predict how changes to the additive, the fuel, or the engine will affect the emissions. Additionally, this research will benefit atmospheric chemists by improving their forecasts of smog and related problems. Finally, the PI will develop a series of educational modules that illustrate how changing the structure of a fuel changes its combustion properties, and will create hands-on design projects in which students build different combustion devices.The most widely used fuel additive in low-temperature compression-ignition engines is 2-ethyl-hexyl nitrate (2EHN). The hypothesis is that a significant percentage of the nitrogen in 2EHN exits the cylinder as hydrogen cyanide and other highly toxic compounds. To test this hypothesis, shock tube experiments, electronic structure theory, and kinetic modeling studies will be combined to quantify the various nitrogen containing products and establish the reaction pathways that produce them. Additionally, the PI will collaborate with engineers at Argonne National Laboratory to develop computational models to predict how 2EHN will interact with real-world transportation fuels, such as n-heptane, iso-octane, and toluene. Many key pathways in low-temperature compression-ignition engines are kinetically controlled, so these engines produce different combustion byproducts than conventional, high-temperature engines. Knowledge of these pathways is particularly important for fuel additives that contain nitrogen. The majority of our understanding of nitrogen chemistry is limited either to high temperatures in excess of the thermal NOx limit, or low temperatures in the atmosphere. This proposal will fill in a crucial gap in our understanding of nitrogen chemistry by elucidating the key chemical pathways for the oxidation and reduction of nitrogen containing species below the thermal NOx threshold.