Simulation Research on Ammonia-Hydrogen Mixed Combustion Engine

Abstract

To achieve low carbon emissions throughout the entire lifecycle, including preparation, storage, transportation, and use, hydrogen(H₂) and ammonia(NH₃) energy represent effective solutions to address significant challenges in energy development. Hydrogen stands out as a promising carbon-free energy carrier due to its calorific value, which is roughly three times that of gasoline or diesel. However, hydrogen's high flammability, high diffusivity, and low liquefaction temperature limit its broad application in engines. Ammonia, on the other hand, serves as a hydrogen-rich energy carrier with a volumetric energy density three times that of hydrogen, offering a viable solution to mitigate the drawbacks of hydrogen energy in engines. Nevertheless, ammonia's laminar flame speed is relatively slow, about one-fifth that of gasoline, and it is not easy to ignite. Combining ammonia and hydrogen in combustion can address issues related to the challenging control of hydrogen combustion and the difficulty of igniting ammonia. The application of ammonia-hydrogen mixed combustion in vehicles involves using ammonia cracking as the hydrogen supply source, which circumvents the problem of hydrogen storage. Utilizing low-carbon and zero-carbon fuels remains the sole path to achieving environmentally friendly and sustainable transportation development. This article focuses on the ammonia-hydrogen mixed combustion model integrated into vehicle engines and explores engine thermal efficiency and emissions across various ammonia-to-hydrogen ratios.