Range Model of Electric Vehicles With Multi-Speed Transmissions

Range-prediction models of electric vehicles (EVs) are essential for vehicle designers because range is still a major problem in EVs. Most range models are only available for EVs with fixed gearing. However, recent developments in EVs incorporate multi-speed transmissions (MSTs). Furthermore, transmissions are modeled only with a constant efficiency in most EV range-prediction simulation results available in the literature. For this reason, a simple and accurate range model for EVs with MSTs is proposed in this paper. In order to predict the range of EVs with MSTs accurately, the transmission efficiency is estimated by means of the transmission mathematical model. The efficiency results are verified with a comprehensive model that has been validated experimentally. A case study pertaining to the GM EV1 with a two-speed novel modular transmission is provided. Moreover, simulation results under constant efficiency are included to show the advantages of the proposed model in range-prediction. Our simulation results show that a more accurate range-prediction can be obtained by means of the proposed model.