Browse Publications Technical Papers 2019-26-0109

Development of 2 Speed Automatic Transmission for Battery Electric Two Wheelers 2019-26-0109

Improving vehicle performance in terms of both torque and power is a strong customer need in both conventional and electric vehicles. In this work different two speed automatic transmission (AMT) concepts are developed to improve the energy efficiency and performance of battery electric two wheelers. Developed transmission systems are simple, compact and cost effective and results in relatively high energy efficiency of an electric motor by allowing the electric machine to operate at peak performance zones. The unique control strategy ensures motor is operated at higher efficiency zones to minimize the overall energy consumption. Virtual simulations of electric vehicle model were carried out for different driving conditions and optimal transmission ratios were determined. These simulations showed that a two-speed AMT could improve both energy efficiency and vehicle performance. Mechanical behaviors such as gear shift characteristics, linear and angular velocities, inertia and forces of each components in these concepts are analysed by using Multi body simulation tool MSC Adams & forces predicted here are further used for durability studies of these components. Physical Prototypes of two speed transmission systems are developed and tested on a test rig to study various parameters closely and validate their functionality. This system combines superior shifting accuracy, high transmission efficiency with increased grade ability (Torque @ wheel increased by 25%) and results in substantial improvement in acceleration and pickup while retaining top vehicle speed without much compromise. So the Schaeffler 2 speed AMT shows significant potential for realizing extended mileage with the advantages of motor downsizing, high transmission efficiency (>95%), improved energy saving can effectively solve the limitations of conventional fixed transmission battery electric vehicles


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