The effects of ammonia addition on the emission and performance characteristics of a diesel engine with variable compression ratio and injection timing

Ammonia, future of the carbonless marine fuel, presents significant potential in achieving zero-emission targets within maritime transportation. In this context, this study explores the use of an ammonia/diesel fuel mixture in a diesel engine, employing both experimental and numerical methods. We focus on the impact of injection timing and compression ratio to optimize the engine while using ammonia/diesel mixture in terms of both engine performance and exhaust emissions. The results show a decrease in engine power with an increasing content of ammonia, reaching the lowest power of 4.53 kW at 60% ammonia content. On the other hand, the increase in compression ratio generally enhances engine power. Thermal efficiency shows an increase up to 40% ammonia content, followed by a decline. CO₂ emissions significantly reduce with an increase in ammonia content, reaching the lowest level, especially at 60% ammonia content. NO emissions rise with increasing ammonia content up to 40%. Furthermore, increasing the compression ratio reduces CO₂ emissions and contributes to an increase in NO_x emissions. These findings have assessed the potential usage of ammonia-diesel fuel mixture with regards to environmental impacts and energy efficiency in internal combustion engines.