Effects of Direct Water Injection on the Nitrogen Oxide Emission Characteristics of Marine Diesel Engines

This study examines the issue of diesel emissions from vehicles and vessels and their impact on environmental degradation with a focus on nitrogen oxide (NOx) emissions and their contribution to air pollution-related deaths worldwide. The novelty of this work is the use of computational fluid dynamics simulations to investigate the effectiveness of water addition for reducing NOx emissions. This study considers two methods of water addition, i.e., injection of water and air into a combustion chamber and mixing of water with fuel before injection. Adding water to air systems at 10% and 20% ratios reduces NOx emissions by 5% and 10%, respectively, whereas mixing water with fuel at the same ratio reduces NOx emissions by 25%. Increasing the water percentage can further reduce emissions by up to 35%. This study indicates that water addition is a cost-effective method for reducing emissions, and numerical analysis is crucial for demonstrating its effectiveness.