Experimental investigation on the performance of pure ammonia engine based on reactivity controlled turbulent jet ignition

Ammonia-based internal combustion engines (ICEs) produce carbon-free emissions. However, the application of ammonia in ICEs results in difficult ignition, combustion instability, and reduced engine performance. In this study, the pre-chamber turbulent jet ignition (TJI) technology was applied to overcome these issues. Two TJI modes based on a self-designed scavenging pre-chamber were proposed in the engine experiments. These modes were air-assisted injection mode (TJI mode 1) and air-assisted injection mode with an air-scavenging process (TJI mode 2). The results demonstrated that the TJI system optimized the combustion stability and improved the burning rate of the ammonia engine. TJI combustion mode had a superior indicated mean effective pressure (IMEP), coefficient of IMEP variation (CoVIMEP), and indicated specific fuel consumption (ISFC) compared with the SI mode, particularly the TJI mode 2 with scavenging process. The NOx and NH3 emissions were high for the ammonia engine regardless of the ignition mode. However, the emissions decreased after adopting the TJI combustion mode. This study provides valuable insights into the application of the TJI ammonia engine to achieve zero-carbon emissions.