Investigation on the influence of nozzle geometry variations on Diesel jets

The internal combustion engine is currently the most important cornerstone of mobility. To ensure that it also remains competitive with other drive concepts in the future, further development is unavoidable to comply with the ever-stricter requirements as they pertain to environmental compatibility.When it comes to diesel-powered internal combustion engines, the injection system in particular is critical for mixture formation and is therefore the focus of research aimed to reduce emissions before after treatment and increase engine efficiency. Characterizing the injectors used and acquiring a comprehensive understanding of the spray behavior are imperative for deriving further combustion-relevant injection variables. This knowledge lays the foundation for identifying optimization potentials and delicate variables.The standard measuring technology used to investigate injectors illuminates merely one aspect of the injection process. This is why, during previous research work, efforts were already undertaken to evaluate the results of the different measuring technologies in combined fashion in order to acquire a more comprehensive picture of the mechanisms behind the spray disintegration and the resulting fuel spray [1][2].The focus of this paper is to investigate geometry variations of the nozzle hole of passenger car diesel injectors and their effects on the behavior of the spray. The overarching objective is to leverage the evaluation of the partial results of three measuring technologies to obtain a holistic analysis of the injectors and, thus, to understand the correlation between the nozzle hole geometry and the ensuing properties of the fuel spray.