Abnormal combustion and NOx emissions control strategies of hydrogen internal combustion engine

Fossil fuel use raises concerns regarding environmental pollution and limited storage capacity. Internal combustion engines significantly depend on the conventional gasoline and diesel, emphasizing the need for alternative fuels. Hydrogen is currently gaining attention as a potential clean energy alternative to traditional fossil fuels owing to its zero carbon emissions, high energy density, fast refueling, compatibility with the existing infrastructure, flexibility, and versatility. Hydrogen use in internal combustion engines signifies a paradigm shift in the engine community toward cleaner and more sustainable transportation solutions. However, challenges such as production costs, distribution infrastructure, and security requirements must be addressed for widespread use. Ongoing research aims to overcome these challenges and enhance the feasibility of using hydrogen as a carbon-free energy source for the engines. This study comprehensively overviews recent research progress and advancements in hydrogen internal combustion engine in terms of the mixture formation mechanism, combustion modes, abnormal combustion mechanism, and the formation mechanism of the nitrogen oxide emissions. In addition, advanced combustion control strategies and technologies have been proposed and summarized to regulate abnormal combustion and nitrogen oxide emissions in the hydrogen engine. The main objectives of this study are to overcome or address these challenges and problems and further enhance the feasibility of hydrogen as a carbon-free alternative fuel for the engine.