Fundamental studies of auto-ignition and combustion in a low-emission natural gas engine

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It is well known that natural gas (NG) does not auto-ignite under conventional diesel engine operating conditions. Hot surface ignition (HSI) provides a practical solution to this problem. Therefore, the objectives of the proposed research program are twofold; at the most fundamental level, the research is intended to develop an improved understanding of the role of entrainment and mixing on the ignition and combustion of turbulent gaseous fuel jets impinging on a hot surface. At an applied level, the objective of the research is to develop a robust hot-surface igniter for use in a direct-injected, natural gas fuelled, diesel cycle engines.An integrated series of controlled rig-based experiments, optically-accessed engine experiments, and numerical simulations will be performed using methane as a control fuel. The proposed research program will provide a better fundamental understanding of the requirements for reliable ignition and combustion in a HSI direct-injected NG engine. The data acquired during this study will enable improved numerical models of ignition and combustion to be developed for this class of engine and will thus, both directly and indirectly, facilitate the development of an optimized NG HSI diesel-cycle engine. The optimized engine will offer substantial CO2 reduction benefits and reduced levels of other pollutants emissions when compared to conventional diesel and spark-ignited engines. In contrast to the duel-fuel 'pilot-ignited' operation of direct-injection NG engines, the HSI approach is readily applicable to medium and light-duty applications. Accordingly, direct-injected NG HSI engines will be well suited to power future, fuel-efficient hybrid vehicles.