CFD Simulation and Robust Design Optimization of the Valve Seat and Orifice Plate in Port Fuel Injector

The mass flow rate of the fuel-air mixture can vary due to the geometry and dimensions of the valve seat and orifice plate at the tip of the port fuel injector. This study aims to reduce the standard deviation of the mass flow rate by optimizing four design parameters of the valve seat defined at the top (CHA1 – the angle between the valve seat and the bore wall and CHH1– its horizontal distance) and the bottom (CHA2 – the angle of the chamfer from the bottom of the valve seat and CHV2 – its vertical distance) of the edge breaks to guarantee a constant mass flow rate during its operation. The sensitivity analysis is implemented with the CFD simulation to generate the Design of Experiment (DOE) using ANSYS CFX and optiSLang. This created the correlation between design parameters and the averaged mass flow rate. The results indicate that CHA2 was the most impacting parameter on the mass flow rate. The Robust Design Optimization (RDO) is performed based on the Metamodel of Optimal Prognosis (MOP). Furthermore, the optimization loop processes the correlation function obtained from MOP using the Evolutionary Algorithms (EA) optimization method by keeping the standard deviation and the tolerance of the design parameters constant. In conclusion, the implemented EA optimization can reduce the standard deviation of the mass flow rate by approximate 51% and the new nominal designs at the valve seat edge breaks are obtained.