Numerical Modeling and Emission Analysis of Hydrogen Compression Ignition Engines under Variable Operational Parameters for Diesel-to-Hydrogen Conversion Optimization

This study presents a comprehensive numerical analysis of hydrogen compression ignition engines (HICE) under varying inlet temperatures and compression ratios, aimed at improving performance and emissions for retrofitting existing diesel engines to operate on hydrogen(Stępień, 2021). The simulation compares hydrogen and diesel combustion, focusing primarily on power output, thermal efficiency, and NOx emissions for each parameter set during gas combustion. The composition of industrial engines indicates substantial advantages in elevating the start temperature to 500 K to 600 K, resulting in enhanced power and efficiency of approximately 55% within moderate compression ratios of 20-24. A diesel engine can be retrofitted for hydrogen operation at a compression ratio of 20, provided preheating is implemented. This moderate preheating technique effectively reduces NOx emissions to tolerable levels without necessitating extremely high compression ratios, so rendering hydrogen hypergolic and allowing the engine to function normally. Numerous studies substantiate the claim that hydrogen CI engines can function in this manner (Lee et al., 2013), indicating that low temperatures may adversely affect hydrogen performance, as even utilizing the compression ratios of current diesel engines could provide a viable motivation for hydrogen utilization. The research indicates that this method facilitates the conversion of diesel engines to hydrogen fuel, diminishes reliance on fossil fuels, promotes a clean energy transition, and enhances emissions control techniques.