Recent developments in electric vehicles incorporate multi-speed transmissions to improve the electric vehicle range and performance. Similar to transmissions for fossil-fuel vehicles, those for their electric counterparts undergo topology changes during gear-shifting. However, this important phenomenon has been overlooked in the development of transmission mathematical models, which results in inaccurate prediction of the transmission dynamic response. In this study, a topology-change model based on the impulse-momentum relation is developed to address the topology change of multi-speed transmissions in electric vehicles during gear-shifting. An orthogonal complement is introduced to eliminate the non-working constraint forces. The velocity jump brought about by topology changes is given due attention. A case study is included, whereby the model is applied to a novel modular multi-speed transmission for electric vehicles. First, tests are conducted on the transmission experimental testbed; then, the test results are reproduced in simulation using the model developed herein. Moreover, the velocity jump of the gear-shifting is computed by means of the model. Subsequently, simulation of the transmission gear-shifting incorporating the velocity jump is conducted. It is shown that the topology-change model improves the accuracy of transmission mathematical models in predicting transmission dynamic responses during gear-shifting.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.