Operating Limits for Ammonia Fuel Spark-Ignition Engine

The objective of this paper is to provide new data about the possibility of using ammonia as a carbon-free fuel in a spark-ignition engine. A current GDI PSA engine (Compression Ratio 10.5:1) was chosen in order to update the results available in the literature mainly obtained in the CFR engine. Particular attention was paid to determine the lowest possible load limit when the engine is supplied with pure ammonia or a small amount of H-2, depending on engine speed, in order to highlight the limitation during cold start conditions. It can be concluded that this engine can run stably in most of these operating conditions with less than 10% H-2 (of the total fuel volume) added to NH3. Measurements of exhaust pollutants, and in particular NOx, have made it possible to evaluate the possibility of diluting the intake gases and its limitation during combustion with pure H-2 under slightly supercharged conditions. In conclusion, the 10% dilution limit allows a reduction of up to 40% in NOx while guaranteeing stable operation.

Automated summary

This paper explores the potential use of ammonia as a carbon-free fuel in a spark-ignition engine, finding that adding less than 10% H-2 to NH3 can allow the engine to operate stably in most conditions. Introducing a 10% dilution limit of H-2 into the intake gases can reduce NOx emissions by up to 40% while maintaining stable operation.