Design of HEV-relay using response surface method to improve bounce characteristics

HEV-relay plays a significant role as a controlling switch which operates a gasoline engine and an electric motor by an electric controlling system of a hybrid electric vehicle (HEV). The relay has some problems in the operating process. First, the bounce of a moving contact by high speed impact makes unstable current flow because the relay completes an operating process only in a few milli-seconds. Second, it is difficult to design the actuating system to satisfy the desired design specification due to the complex design variables of HEV-relay. In this research, the electrical contact and springs consisted in HEV-relay are designed to improve bounce characteristics and to satisfy the desired design specification in the operating process. The shape of electrode is modified to reduce the bounce time in close process of HEV-relay. And the spring stiffness and initial compression force of each spring are optimized in order to satisfy the design specification such as operating time and velocity. The design procedures are based on the numerical simulation using LS-DYNA3D. The optimum performance of the HEV-relay is determined by response surface method (RSM) as the design methodology.