Investigation of alternative fuels for various applications: experimental and life cycle assessment studies

This thesis research presents an experimental investigation and life cycle assessment (LCA) of alternative fuels and fuel blends, with the objective of assessing their environmental sustainability and combustion performance in a gasoline engine. The experimental component investigated the enrichment of conventional fuels (gasoline, propane, methane) and alcohol fuels (ethanol, methanol) with pure hydrogen and oxyhydrogen (HHO) at volumetric mix ratios of up to 20%. Emissions (CO2, CO, HC, and NOx), energy/exergy efficiency, and electrical power output were evaluated using a spark-ignition engine connected to a generator. The findings indicated that both hydrogen and HHO enrichment significantly lowered carbon-based emissions. Hydrogen blending resulted in CO2 reductions of 22–31%, CO reductions of 39–60%, and HC reductions of 21–60%, while boosting power output by 2–16%. Nonetheless, hydrogen substantially increased NOx emissions by 200–420%, due to increased combustion temperatures. Conversely, HHO blending lowered CO2 emissions by 24–30%, CO by 40–43%, HC by 25–35%, and NOx by around 22%, while increasing power output by 1.5–17%. Improvements in energy efficiency were particularly significant in methane, increasing from 42.0% to 49.9% with H2 and 50.6% with HHO enrichment, hence validating thermodynamic improvements. The LCA phase of the thesis study assessed 18 fuels in relation to eight important environmental impact categories. Hydrogen has shown to be the most sustainable alternative, exhibiting the lowest global warming potential (0.003 kg CO2 eq/MJ) and abiotic depletion potential. Ethanol and formic acid demonstrated remarkable environmental performance. Diesel, gasoline, and kerosene had the highest impacts on global warming potential, acidification potential, and human toxicity potential. Marine ecotoxicity potential showed variability, with butanol and synthetic gas demonstrating poor performance, while methane and soy biodiesel presented better-balanced profiles. This thesis study offers vital insights for clean energy transitions, highlighting that while no specific fuel shines across all categories, hydrogen, ethanol, and formic acid continually emerge as the most viable choices for sustainable power and transportation applications.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Ontario Institute of Technology

Year dc:date.issued

2025

Author dc:creator

• Karasu, Huseyin

Advisor dc:contributor.advisor

• Dincer, Ibrahim

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10155/1987

OAI identifier oai:identifier

oai:ontariotechu.scholaris.ca:10155/1987