Comparative analysis of thermal load on parts of marine diesel engines when converting their operation to renewable and low-carbon fuels

Abstract

The solution to the problem of decarbonizing maritime transport by IMO and EU regulations focuses exclusively on reducing greenhouse gas emissions of CO2, CH4, and N2O, calculated based on carbon emission equivalents, and improving the energy efficiency of ship power plants [MARPOL 73/78 (Annex VI) and COM (2021) 562-final 2021/0210 (COD)]. Ensuring engine reliability is primarily about solving local issues related to the operability of individual components and parts, which is typical for operational comparisons of engines running on various fuels. In this context, it is relevant that methodological tools be developed and applied for the assessment and study of thermal loads on the most critical components of the ship engine, namely the cylinder-piston group, during the retrofitting of operational diesel engines. This approach will optimize the performance indicators of ship engines for the use of renewable and low-carbon fuels (LCF), based on energy efficiency and reliability factors. This publication presents comparative studies on changes in thermal loads on the cylinder-piston group parts of ship engines operating on LCF, utilizing the combined analysis method developed by the authors. The variational methodological modeling encompasses the principal categories of high-speed and medium-speed ship engines utilizing prioritized LCF types for the medium-term perspective of 2030, including LNG and biodiesel. The study evaluates the efficiency of implementing classical practices in diesel engine improvement, such as optimizing the composition of the working mixture (affected by the excess air coefficient), compression changes, and fuel combustion intensity.