Sustainability (Switzerland), cilt.18, sa.2, 2026 (SCI-Expanded, SSCI, Scopus)
The transition toward sustainable energy systems necessitates innovative solutions that reduce greenhouse gas emissions while improving fuel efficiency in existing combustion technologies. Hydrogen has emerged as a promising clean energy carrier; however, its widespread deployment is limited by challenges associated with large-scale transportation and storage. This study investigates a practical alternative in which hydrogen-rich syngas produced via steam methane reforming (SMR) is directly integrated into the diesel engine intake, thereby eliminating the need for fuel transport, storage, and separation while supporting a more sustainable fuel pathway. A validated computational fluid dynamics (CFD) model was developed to examine the effects of varying SMR gas mixture ratios (0–20%) on engine combustion, performance, and emissions. The findings reveal that increasing the SMR fraction enhances in-cylinder pressure by up to 15.7%, heat release rate by 100%, and engine power output by 102.5% compared to conventional diesel operation. Additionally, under SMR20 conditions, CO2 emissions are reduced by approximately 12%, demonstrating the potential contribution of this approach to decarbonization and climate mitigation efforts. However, the rise in in-cylinder temperatures was found to increase NOx formation, indicating the necessity for complementary emission control strategies. Overall, the results suggest that direct SMR syngas integration offers a promising pathway to improve the environmental and performance characteristics of conventional diesel engines while supporting cleaner energy transitions.