Design of Alternative Automatic Transmission for Electric Mopeds
Abstract
The number of automobiles has seen an alarming rise in the recent years. In the year 2014, the number of road vehicles produced annually increased to 87.23 million vehicles from around 40 million in 2000. This shows that production has increased to more than twice the volume in only 14 years. This has also caused a rise in the pollution levels. Global CO2 levels are on the rise due to increased pollution, contributing to the greenhouse effect. Hence it is very important to reduce our dependency on gasoline driven vehicles. Electric vehicles are a good alternative to these. The advent of electric vehicles is marred by factors like unavailability of charging stations and most importantly not being able to match the performance parameters offered by gasoline driven vehicles. Hence a driveline setup has been designed to increase the performance parameters like gradeability and top speed of an electric moped to set it at par with the gasoline powered mopeds available on the market. In this report we will focus on the design considerations, working principle and the mechanism for the said driveline as well as the design calculations and the CAD model.
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Introduction
Electric vehicles are said to be the future of the automobile technology. There are overwhelming advantages of electric vehicles over gasoline vehicles. With gasoline-electric hybrid power and all-electric power, we can achieve significant cost and environmental savings. By adding more batteries and recharging capability to gasoline-electric hybrid vehicles, we can have plug-in hybrids that offer the range of hybrids (500 miles or more), plus the benefit of all-electric power for short trips, which dramatically reduces the amount of gasoline used. EVs require no gasoline whatsoever and, when recharged from renewable energy sources, produce zero total emissions. In fact, even if we switched from gasoline cars to EVs and plug-in hybrids recharged by our existing utility grids (which mostly use fossil fuels), we would see a 42% national average reduction in CO2 emissions, according to research by Peter Lilienthal of the National Renewable Energy Laboratory. According to a study, the yearly cost of operating 50 miles per gallon vehicle is $1275 while the same for operating an electric vehicle is just $216. The main issue with using an electric vehicle, in this case an electric moped is the lack of performance. Electric mopeds fall very short in the performance parameters like gradeability, torque and top speed as compared to the gasoline mopeds dominating the market today. The maximum speed possible with an electric moped is just around 16 mph as compared to 40-50 mph top speed of their gasoline counterparts. Hence a mechanical system has been designed which offers both greater power and greater torque whenever the situation demands the need for the same.
Conclusion
The proposed automatic transmission for electric vehicles provides better acceleration as well as velocity as compared to the electric vehicles with the same power range. Thus, a lower wattage power source can be used with this system, which will also help in reducing the battery pack size, eventually reducing the weight of the vehicle. This can help in achieving a better range for the vehicle. As the system incorporates components like the gearbox, centrifugal clutch, chains and sprockets, the transmission efficiency and reliability are high while maintenance and manufacturing time and cost are low. The automatic system is easy to drive for amateur drivers and provides comfort reducing driver fatigue especially while riding in traffic. Hence, with some research the automatic transmission system can be effectively used in most modern day electric vehicles.