Experimental Study on Engine Performance Fueled with Ammonia-Hydrogen Blend Ignited by Diesel Pilot

The global energy crisis and drastic climate change are continuously promoting the implementation of sustainable energy sources. To meet the emission standards and carbon-neutrality targets in vehicle industry, ammonia is considered to be one of the promising carbon-neutral fuels. However, running the engines on high amounts of ammonia may lead to significantly high ammonia slip. This originates huge safety concerns. Therefore, hydrogen is added in certain ratio with ammonia to promote combustion and reduce ammonia slip. Furthermore, adding diesel as a pilot fuel further facilitates the combustion reactions. This experimental study investigated the effect of different ammonia-hydrogen blend ratios on in-cylinder pressure, heat release rate, cumulative heat release, indicated mean effective pressure (IMEP), indicated thermal efficiency (ITE), CA5 and CA50. This effect of blend ratios was tested for varied diesel pilot amounts and timings. The results show that increasing the hydrogen amount in ammonia-hydrogen blend from 20% to 40% (by vol.) increased the in-cylinder pressure and heat release rate. In addition, significant increasing trend for cylinder pressure and heat release rate was observed by increasing the diesel pilot amount from 5% to 10% to 20% (by vol.) and pilot timing from 9 to 11 and 13 DBTDC. Furthermore, increasing the diesel pilot amount increased the IMEP and ITE.