Variability of CVT Extends the Repertoire of the Electric Car

Authors

Ir. F. van der Sluis, L. Römers MSc, Ing. G.-J. van Spijk, B. Mani MSc, Bosch Transmission Technology B.V., Tilburg:

Year

2022

Print Info

Production/Publication ÖVK

Summary

Multi-speed transmissions offer differentiation of electric powertrains as they enable further optimization of the main KPIs performance, energy consumption, comfort and cost. This paper presents simulation results of a Continuously Variable Transmission (CVT) for electric drivetrains (CVT4EV) applied in vehicles from C to LCV class and highlights specific use cases such as vehicles driving in low-speed cycles and AWD vehicles. With its large ratio coverage, this transmission variant offers enhanced drive torque to fulfil the wider set of actual vehicle requirements at the highest comfort level. The smooth variability of this typical transmission feature offers benefits in comfort, energy, performance and cost for several use cases.

A simulation study on AWD vehicles shows that CVT4EV considerably reduces drag losses. It improves energy consumption over WLTC by up to 3% and reaches launch acceleration improvements up to 50%. A further study evaluates vehicles that typically travel at cycles with low average velocity. Delivery trucks, city buses and shuttles must be able to drive off fully loaded on steep hills but still reach highway speeds during shorter periods of use. For these specific use cases, CVT4EV reduces both the required motor torque and energy consumption. Smooth launches and the absence of torque interruptions provide the highest level of comfort. The energy savings and reduced torque demand offer a potential decrease of total cost of ownership (TCO) by reduced operational costs and reduced electric motor, inverter and battery cost. This KPI is especially relevant for commercial transportation of passengers and goods.

ISBN

1920-2323-23-1

Number of pages

15 Order