Energy, exergo-economic, sustainability, and combustion analysis of a dual-fuel diesel engine operating with hydrogen fuel

To evaluate the hydrogen fuel feasibility in automotive applications, conventional combustion, performance, and emission analysis alone are not satisfactory. Thermodynamic analysis (energy and exergy analysis), sustainability, CO₂ impact, and economic analysis are also significant. The work investigates the impact of hydrogen inclusion and its various energy fractions in a modified compression ignition (CI) engine that works under diesel. The engine was tested at full load condition of 4.2 bar brake mean effective pressure (BMEP) at a constant speed of 1500 rpm. Gaseous hydrogen was introduced through port fuel injection (PFI) at different injection durations, and by this, different hydrogen energy share (HES) values of 0 %, to 39.48 % were achieved. Hydrogen addition has significantly contributed to the combustion process improvement. The highest brake thermal efficiency (BTE) was registered at 32.34 % HES value and was 11.89 % more than neat diesel operation. The first law and second law efficiency were also improved, with the highest values at 22.43 % HES, which were 4.06 % and 6.39 % more than neat diesel operation. Unburned Hydrocarbon (HC), carbon monoxide (CO) and smoke emissions were reduced for all HES values. However, due to enhanced combustion, carbon dioxide (CO₂) and oxide of Nitrogen (NOx) emissions increased with maximum values for both at 39.48 % HES. The sustainability index (SI) was within the range of 1.230–1.255, always higher than unity. Environmental impact, enviro-economic and enviro-social values also showed favourable values. At the same time, the CO₂ impact and the cost analysis implied that hydrogen-diesel dual-fuel engines need improvement.