Investigation of injection and flow characteristics in an electronic injector featuring a novel control valve

Abstract

Improving the dynamic response of fuel injectors is crucial for enhancing internal combustion engine performance, as it is a prerequisite for implementing advanced injection strategies. However, traditional injectors often encounter increased cavitation and return fuel quantity within the control valve during the enhancement of dynamic response. This study introduces a novel electric injector featuring a closable inflowing control-orifice in the control valve, designed to improve dynamic response while reducing cavitation and fuel return. Performance comparisons were conducted using validated 1D and 3D CFD models. These comparisons indicate that, with the same outflowing control-orifice area, the novel injector improves opening and closing responses by 36.76 % and 19.23 %, respectively, while reducing return fuel quantity by 82.68 %. Additionally, during a single injection cycle, the novel injector’s control valve achieves significant reductions in average cavitation volume and bubble condensation rate by 64.49 % and 60.77 %, respectively, at critical locations. This enhancement improves the flow coefficient and durability of the control valve. Moreover, during the injection process, the novel injector reduces the average hydraulic pressure on the upper end face of the needle valve by 79.22 % and achieves a more uniform hydraulic pressure distribution on this surface. These improvements enhance the axial and radial stability of the needle valve, effectively reducing the degree of torque imbalance experienced by the needle valve.