Electro-Dynamical Modeling of a Solenoid Switch of Starter Motors

The goal of this paper is to model electro-dynamically the pinion-engaging mechanism (PEM) of starter motors. The purpose of the PEM is to switch a high current by means of relatively low control current. The PEM is the system of components (solenoid switch, pinion-engaging lever, and overrunning clutch with drive pinion) that engages the drive pinion with the ring gear. The solenoid switches consist of a pull-in winding and a hold-in winding and a movable iron core. The electro-dynamic model of the solenoid switch contains the inductance and its partial derivatives which depend on the current and the position of the solenoid armature. An electromechanical measurement method is proposed to determine the inductance and its derivative for various positions of the solenoid switch. The experimental results are implemented in the electro-dynamic model using energy-based modeling applying the Euler-Lagrange formalism.