Small compact electric vehicle for practical use and its repeated start-stop tests

摘要

We are proposing a small electric vehicle which uses a low powered battery (7.2 V, approximately 2 Ah) to be used for shopping by the elderly. We fabricated a vehicle which demonstrated a total running time of over 30 minutes with a running velocity of over 3 km/h using the battery in a previous project. For this study, we have improved the vehicle in terms of both operational comfort and running performance. In order to improve operational comfort, two upgrades were implemented. First, the transmission device box was moved and installed in a position so that the driver is able to rest their feet on it. Secondly, a seat with a back was installed instead of a bicycle saddle. Regarding running performance, we were able to improve the power transmission efficiency by using wheels with smaller diameters, and reduce the coefficient of rolling friction by using thick and firm tires. Furthermore, steady running tests and repeated start-stop tests were conducted simulating actual vehicle use. As a result, the vehicle was able to operate over a longer distance than the previous vehicle. And, we confirmed that the running distance during the start-stop testing was shorter than that of the steady running test. This paper will present the design with respect to usability and running performance and present the experimental results of the steady running tests and the start-stop tests.