The adoption of electric mobility may not be moving at the speed the Indian government wishes for. However, the robust government push in the form of the FAME II scheme announced earlier this year has infused hope about facilitating an electric vehicle ecosystem in the country. Pune-based Team Drivetrain offers a solution in this area.
A five-member student team – Team Drivetrain – spearheaded by Prasanna Agnihotri, worked on developing a novel transmission system for electric two-wheelers. Along with his team members Jay Gaikwad, Ajinkya Kate, Rushikesh Sagare and Shriniwas Sirsat – all third-year mechanical engineering students from Pune-based Jayawantrao Sawant College of Engineering – the team won the ‘Most Popular Project Award’ at KPIT Sparkle 2019, garnering over 11,000 online votes, and taking home a cash prize of Rs 1 lakh.
The automotive industry is increasingly focussing on leveraging green energy and in this context, electric vehicles are seen as the best transportation choice. The ever-increasing air pollution is a serious environmental concern coupled with the country’s inflated import bill. All of these make it a compelling reason to switch to electric vehicles. It is very much in public domain that emissions from internal combustion engines can cause immediate and long-term detrimental effect on humans and the environment. And that explains why the automotive industry intends to take the ‘electrification’ route.
Team Drivetrain conducted a detailed study of the behaviour of the electric two-wheelers in the country. The team soon found out that electric two-wheelers often encounter challenges, while climbing gradients. They realised that such electric two-wheelers equipped with a hub motor were having higher battery consumption and lower motor life.
That led the team, in mid-2018, to start focussing on and developing an efficient transmission system between the motor shaft and the driven wheel to enhance the load carrying capacity and gradeability of electric two-wheelers.
The transmission system for electric two-wheelers is a combination of gear, pulleys and belt. To move the vehicle from rest position, the arrangement of components in the drivetrain will ensure maximum torque at the output shaft. After achieving maximum torque, the arrangement of components will switch so as to achieve maximum speed at output shaft during cruising. The planned arrangement of components (electric motor, gears, pulleys, transmission belt, etc.) will deliver maximum power to move the vehicle and help in accelerating.
Team Drivetrain claims the transmission system they’ve developed will deliver maximum efficiency and long life of an electric vehicle as compared to the existing transmission system. The hub motor in the drivetrain has been replaced by a centrally mounted Brushless DC Electric Motor (BLDC) of 1.2 kW, which generates power of 1.6 hp at 3,000 rpm with maximum rated torque of 5.2 Nm. The BLDC motor is controlled with a non-reprogrammable controller.
The single stage gearbox is connected to the motor that provides a speed ratio of 2.5. And to transmit power from the gearbox to the rearwheel the positive belt drive is mounted between them. The use of timing pulley improves meshing with the belt, which increases the strength and load carrying capacity due to positive drive and is slippage-free. The 48 V lithium-ion battery, and the 40 Ah of current supply helps the motor run the system.
Team Drivetrain is designing a data logging system that will log the real time data in a CSV file. The team has installed temperature sensors to measure real-time temperature of batteries and motor in running condition. Further, Team Drivetrain leveraged IR sensors for measuring the wheel rpms as well as the motor shaft. By using the performance graphs from the above data with the help of Excel sheet or other similar software, the team analyses the efficiency, load carrying capacity and the performance of the designed drivetrain on the gradient road.
Team Drivetrain’s transmission system increases the overall performance of electric two-wheelers, claims the team. They monitored various parameters to calculate the power losses. This transmission system for electric two-wheelers can increase the efficiency and reliability of the transmission system, ensure reduced operating costs, higher profitability, along with live tracking of vehicle position, range prediction and route planning, said Prasanna.
Team Drivetrain is indebted to its mentor Dr VK Bhojwani, a faculty member of Jayawantrao Sawant College of Engineering for providing them with constant inspiration towards making this drivetrain project a success. The Prasanna-led team also appreciated the unstinted guidance of their college seniors Shubham More and Saurabh Pachpande in developing this drivetrain. The team also received technical support from Autopluster.
Team Drivetrain intends to offer this innovation to different government services, e-commerce companies such as Swiggy, Amazon as well as bike rental services. Going forward, Team Drivetrain is keen to work further on the design of this drivertrain, in terms of making it more customised after eliciting feedback from what customers are looking for. The team has plans of floating a start-up in the near future.
TEXT: Suhrid Barua