Influence of Intake Charge Temperature and EGR Rate on the Combustion and Emission Characteristics of Ammonia/Diesel Dual-Fuel Engine 2024-37-0025

Ammonia has emerged as a promising carbon-free alternative fuel for internal combustion engines (ICE), particularly in large-bore engine applications. However, integrating ammonia into conventional engines presents challenges, prompting the exploration of innovative combustion strategies like dual-fuel combustion. Nitrous oxide (N2O) emissions have emerged as a significant obstacle to the widespread adoption of ammonia in ICE. Various studies suggest that combining exhaust gas recirculation (EGR) with adjustments in inlet temperature and diesel injection timing can effectively mitigate nitrogen oxides (NOx) emissions across diverse operating conditions in dual-fuel diesel engines. This study conducts a numerical investigation into the impact of varying inlet charge temperatures (330K, 360K, and 390K) and EGR rates (0%, 10%, and 20%) on the combustion and emission characteristics of an ammonia/diesel dual-fuel engine operating under high-load conditions, while considering different shares of ammonia energy. Computational fluid dynamics (CFD) simulations are executed using Converge software. Subsequently, multi-linear regression models are developed, utilizing ammonia share, inlet charge temperature, and EGR rate as independent variables, and emission parameters as dependent variables. The best-fitted regression model can be employed to analyze the response surface of performance parameters. The optimal CO2 reduction, approximately 30%, is observed under the conditions of (390K, 40% NH3, and EGR20), as indicated by the results. Furthermore, under the conditions of (360K, 20% NH3, and EGR20), the findings indicate a notable reduction of NO2, approximately 65% compared to diesel. Additionally, the findings suggest that NH3 reduction peaks at higher temperatures, with approximately a 50% decrease observed.