The maritime industry faces increasing pressure to reduce its environmental impact, particularly through the reduction of greenhouse gas emissions. This thesis investigates the feasibility and technical implications of operating large, low-speed, two-stroke marine engines on hydrogen using low-pressure direct injection. The study addresses the lack of specialized combustion models for hydrogen in large marine engines by developing a tailored in-cylinder thermodynamic combustion model.

A comprehensive literature review highlights hydrogen's unique combustion characteristics, such as high flame speeds, low ignition energy, and wide flammability range, along with associated challenges like pre-ignition, knocking, and NOx emissions. Existing combustion strategies and injection technologies, particularly those adapted from natural gas-fueled engines, are evaluated for their applicability to hydrogen combustion.

The developed combustion model integrates a Seiliger cycle representation enhanced by temperature-dependent thermodynamic properties. It systematically assesses the effects of hydrogen combustion on key engine parameters, including pressure rise rate, peak cylinder pressures, and temperatures, under various operational scenarios. The results highlight the importance of combustion phasing and air-excess ratios in managing hydrogen combustion characteristics, indicating that careful optimisation of injection timing and combustion strategy is crucial to ensure safe and efficient engine operation. Although the model reveals risks associated with aggressive combustion scenarios, such as exceeding mechanical design limits due to high peak pressures, it provides a structured framework for identifying realistic operating conditions for hydrogen LPDI combustion.

This research thus offers critical insights into the technical feasibility and practical limitations of hydrogen combustion in large two-stroke marine engines, contributing valuable guidance for future development and experimental validation efforts.