Towards green marine engines: A review of methanol fueled internal combustion engine

With the global marine industry actively exploring sustainability and making efforts to move towards decarbonization goals, identifying suitable alternative fuels has become a crucial task. Among the numerous types of clean fuels, methanol has become a transitional fuel for the maritime sector to achieve decarbonization goals due to its superior combustion properties. Additionally, methanol has a wide range of sources. It can be produced from coal, natural gas and biomass and its production capacity is distributed all over the world. Asia (with China as the main country), the Middle East and North America are the major bases. In recent years, the production capacity of renewable methanol has been gradually increasing. Renewable methanol is of great significance for achieving carbon neutrality. This review conducts a detailed collation of different types of methanol engines, comparatively analyzes their performance under various operating conditions, and draws corresponding conclusions. The key characteristic parameters encompass ignition delay, knocking, brake thermal efficiency, indicated thermal efficiency, in-cylinder pressure, heat release rate, nitrogen oxides, soot, and carbon monoxide. Based on the examined results, compared with diesel engines, methanol engines exhibit superior performance in terms of emissions. However, methanol fueled engine reduces the thermal efficiency in some cases, which needs more new technologies to improve the efficiency.