Ammonia as a sustainable fuel for diesel engines: Exploring advanced combustion strategies for green transportation

The increasing concern over carbon emissions from IC engines has sparked interest in alternative fuels. While low-carbon fuels like methanol and methane offer some emissions reduction, carbon-free fuels such as hydrogen (H₂) and ammonia (NH₃) hold the potential for more significant reductions. Ammonia, widely used in agriculture, is particularly attractive due to its established infrastructure. It also offers a promising method for storing hydrogen. Notably, green NH₃ production methods using renewable energy sources, making it a sustainable alternative. This review examines research on using NH₃ as alternative fuel for compression ignition (CI) engines. It explores the combustion, performance, and emission characteristics of various operating conditions, including blending, dual-fuel (DF), and adoption of various low-temperature combustion (LTC) strategies, to optimise performance and minimise emissions. The influence of hydrogen addition on NH₃ combustion is also discussed. Additionally, advancements in computational fluid dynamics (CFD) simulations are reviewed to enhance the understanding of NH₃ combustion in IC engines. NH₃ offers a promising pathway to significantly reduce GHG from IC engines. Its potential is significant, especially when used in CI engines with DF mode and advanced techniques like reactivity-controlled compression ignition (RCCI) with optimised ammonia/diesel propositions and injection strategies. Combining ammonia with advanced combustion could offer a sustainable future for IC engine-based transportation.