Sizing the traction motor for optimal fuel efficiency in vehicle electrification

Abstract

This paper presents the traction motor sizing, by means of motor rated torque and speed, for optimal urban fuel economy in two mild and three strong hybridisation powertrains on front-wheel-drive vehicles. The two mild hybrids are belt-integrated-starter-generator and Crankshaft-Integrated-Starter- Generator (C-ISG) systems. The three strong hybrids include an electric machine attached to the front axle, strong C-ISG system where motor is placed between a starting clutch and transmission, and single-mode electric variable transmission. Using the vehicle performance data as constraints and the motor rated torque and speed as the design variables, the objective function is to maximise the urban fuel economy.