Ducted Fuel Injection (DFI) is a concept of growing interest to mitigate soot formation in the diesel combustion process and, simultaneously, break the usual trade-off between soot and Nitrogen Oxides (NOx) emissions. Particularly, the concept is to inject a fuel spray down the axis of a small duct, positioned within the combustion chamber some distance downstream of the injector orifice exit, so that the mixing between air and fuel is increased; as a consequence, a lower equivalence ratio as well as lower engine-out soot emissions are expected. However, the research studies conducted so far have been mainly performed considering only a single-injection event, while state-of-the art diesel engines typically feature highly optimized Multi-Injection (MI) strategies to address emissions, combustion noise and engine performance issues.