Component sizing of traction motor in hybrid powertrains

This paper presents the traction motor sizing for optimal urban fuel economy in two mild and three strong hybridization powertrains on front-wheel-drive vehicles. The traction motor sizes, by means of motor rated torque and speed, are optimized for maximum urban fuel economy. The two mild hybrids are Belt-Integrated-Starter-Generator (B-ISG) and Crankshaft-Integrated-Starter-Generator (C-ISG) systems. The three strong hybrid configurations include an electric machine attached to the front axle of a conventional vehicle, strong C-ISG system where motor is placed between a starting clutch and the transmission, and single-mode Electric Variable Transmission (EVT). Using the simulated vehicle performance data as constraints and the motor rated torque and speed as the design variables, the objective function is to maximize the urban fuel economy. The purpose of this study is to provide a design guideline for hybrid powertrain configurations and component sizing of the traction motors.