Public defence in Energy Technology, M.Sc. Muhammad Saad Akram

Title of the thesis: Advancements in Alternative Fuels Towards Sustainable Engine Combustion 

Thesis defender: Muhammad Saad Akram
Opponent: Prof. David Sedarsky, Chalmers University of Technology, Sweden
Custos: Prof. Ossi Kaario,Aalto University School of Engineering

Advancements in alternative fuels towards sustainable engine combustion 

Climate change is driven by rising greenhouse gas emissions, largely from fossil fuel use in transportation and industrial sector. Internal combustion (IC) engines, which power most vehicles today, contribute significantly to these emissions. While vehicle electrification is growing, IC engines will still remain essential for many applications, making it important to explore cleaner fuel alternatives.
Alternative fuels like ethanol, methanol, hydrogen, and ammonia offer the potential to reduce emissions without requiring a complete shift away from existing engine technology. Studying these fuels provides practical and sustainable solutions to cut carbon emissions while keeping transportation efficient.

The present dissertation studies the fuel spray characteristics and engine performance of potential alternative fuels for IC engines and compares with conventional diesel and gasoline fuels. The fuel sprays are studied optically in constant volume spray chamber using high-speed imaging, while pre-mixed ammonia and hydrogen are used to run heavy-duty single cylinder research engine with diesel as a pilot fuel. Fuel spray study is very important because the spray formation, behavior, and geometry has a vital impact on proper spray atomization and air-fuel mixing, hence on the overall combustion. The present study also focuses on flash boiling spray studies for the concerned fuels. Flash boiling is important strategy to improve the fuel atomization, and evaporation because of the rapid vaporization upon superheating. The tested alternative fuels show different spray behavior both in sub-cooled and flash boiling conditions compared to conventional fuels, thus providing comprehensive understanding of
these fuels before their implementation in real engines. Ammonia with distinctive fuel properties i.e., low boiling point, low viscosity, and  high volatility, compared to the other fuels, experiences the most vaporization under flash boiling conditions. On the other hand, the engine study in this dissertation focuses on the performance impact of pre-mixed ammonia and hydrogen combustion with direct injection diesel pilot. Increasing the amount of hydrogen in ammonia-hydrogen mixture improves the combustion due to hydrogen’s high reactivity and fast burning properties.

Keywords: Alternative Fuels, CI Engine, Decarbonization, Efficiency, Fuel Spray Characterization

Thesis available for public display 10 days prior to the defence at Aaltodoc. 

Contact information: 
E-mail: saadmuhammad.akram@gmail.com 
LinkedIn: www.linkedin.com/in/muhammad-saad-akram