Analysis of ship performance data for the evaluation of marine engines emissions in ports

A reasonable prediction of the air emissions from ships at port is crucial to evaluate the impact on the surrounding inhabited zones and to evaluate and adopt effective countermeasures. A quantification of the power utilized by ships in port is crucial, since the level of emissions from an engine strictly depends on the power supplied. In order to assess the power profile of a vessel during navigation, maneuvering and docking in the port area, several approaches are possible, although experimental measurements are the most reliable source of data. This paper presents results of the post-processing analysis carried out on a large amount of emission data recorded during the navigation of two small ferries operating in the Gulf of Naples. The research activity aims to identifying the different behavior of the propulsion engine in terms of power and emissions (mainly NOx, CO2, Hydrocarbons (HC) in addition to the content of O2 in the exhausts), during the navigation and maneuvering phases of the vessel in port area. The results are presented by means of numerical tables representing the dependence between emissions patterns and significant engine operational data. The long-term goal is to use such results in connection with the simulation of the engine working conditions to derive a prediction of the emissions.