Doctoral theses of the School of Engineering are available in the open access repository maintained by Aalto, Aaltodoc.
Public defence in Energy Technology, M.Sc Maryam Yeganeh
Public defence from the Aalto University School of Engineering, Department of Energy and Mechanical Engineering.
When
–
Where
Event language(s)
English
Title of the thesis: Experimental Studies on Challenges in Hydrogen Heavy-duty and Marine Engines
Thesis defender: Maryam Yeganeh
Opponent: Prof. Mats Andersson, Chalmers University of Technology, Sweden
Custos: Prof. Martti Larmi,Aalto University School of Engineering
Experimental Studies on Challenges in Hydrogen Heavy-duty and Marine Engines
As the world moves toward carbon-free transport solutions, hydrogen is gaining traction as a sustainable alternative fuel for heavy-duty and marine engines. At Aalto University, doctoral researcher Maria Yeganeh has investigated two major technical challenges that must be addressed in the development of hydrogen-powered engines: hydrogen jet dynamics and mixing behavior, and hydrogen pre-ignition triggered by engine lubricating oils.
The first part of the research focuses on hydrogen jet behavior and how injection parameters—such as pressure ratio, injection angle, and nozzle geometry—affect air–fuel mixing. Using high-speed schlieren imaging in a constant-volume combustion chamber, the study demonstrates how injection parameters can be optimized to enhance mixing performance, specifically for low-pressure direct-injection heavy-duty hydrogen engines.
The second part addresses another critical challenge: hydrogen pre-ignition triggered by engine lubricating oils. Using an optical rapid compression expansion machine (RCEM), the study evaluates the reactivity of various engine lubricating oils with different formulations in triggering hydrogen pre-ignition. Results show that lubricants' composition—including both base stock and metal additives like calcium—plays a significant role in either promoting or suppressing pre-ignition.
Overall, the findings of this study provide practical insights for optimizing injection-related parameters and selecting lubricants in hydrogen engines. These advancements support the safe and efficient adoption of hydrogen as a zero-carbon fuel for heavy-duty and marine applications.
The public examination of the doctoral dissertation will be held online via remote connection (https://aalto.zoom.us/j/62257853361) on 8 August 2025 at 12:00.
Keywords: Hydrogen jets, Z-type Schlieren Imaging, Pressure Ratio, Needle Lift, Nozzle Geometry, Injection Angle, Hydrogen Pre-ignition, Engine Lubricating Oil, RCEM, Air-to-fuel Ratio, Compression Ratio
Thesis available for public display 10 days prior to the defence at .
Contact information:
E-mail: maryam.yeganeh@aalto.fi
Doctoral theses of the School of Engineering
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