Experimental and numerical analysis of a high-pressure outwardly opening hollow cone spray injector for automotive engines

The manuscript describes the characterization of a novel outwardly opening pintle-type injector, characterized by a Hollow Cone Nozzle (HCN), as a possible solution for ultra-low emission high-efficiency DI diesel and GDICI engines. In its prototypal version, the injector is capable of generating the hollow cone spray at relatively high injection pressure with a very precise fuel metering. The study concerns some experimental and numerical activities aimed at the analysis of the spray generated by the HCN. A commercial supplier provided the prototypal version of the injector with a dedicated piezoelectric actuation system and a proper choice of geometrical design parameters. The experimental characteristics of the HCN concept (in terms of spray pattern and spatial penetration) were analyzed in a constant volume vessel. The OpenFOAM® libraries, in the lib-ICE version of the code, were employed for the simulation of the spray dynamics after a first validation phase based on the experimental data. Results show a typical spray structure and the overall fluid-dynamics of the outwardly nozzle with a finely atomized spray, circumferentially well distributed, but displaying a reduced tip penetration. These characteristics appear very interesting, being well suited for the application of strategic spray concepts, to be coupled with dedicated combustion chamber designs both for CI and GDICI engines development.