A Feasibility Study on the Low-Load Extension of HCCI Engines from Chemistry Perspectives: Oxymethylene Ether-2 as a Potential Fuel

The potential of oxymethylene ether-2 for extending the low-load operation limit of a homogeneous charge compression ignition (HCCI) engine is examined with a zero-dimensional simulation model. The autoignition instability of HCCI in low-load regimes is a major bottleneck to its commercialization, while the benefits such as suppressed soot formation and minimum nitrogen oxide emissions are notable. To overcome this issue, a highly reactive diesel-like electrofuel is introduced which can be synthesized from carbon dioxide and hydrogen, thus suitable for achieving carbon neutrality in combustion applications. Results demonstrate the possibility of using such fuels for achieving stable low-load operation in HCCI engines, which is realized by combining highly diluted intake mixture and abundant exhaust gas recirculation. The underlying kinetic effects are also investigated for a better understanding of the phenomenon, which provide some insights into determining operation variables of an HCCI engine at low-load condition.