Three years ago, Vikranth Racherla, an Associate Professor in the Department of Mechanical Engineering at IIT Kharagpur, received an email from a student, Seemant Jay, seeking faculty mentors for his project which involved developing an electric racing car.
Professor Racherla responded to the email, enrolled a group of students for the project and began the process. And after three years of research and development, the 20-student strong student team led by Professor Racherla developed the Deshla, an electric three-wheeler with very unique specifications, on campus.
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During their search for funding, they found that an alumnus, Dr Purnendu Chatterjee, had donated US $5,000 for developing e-rickshaws. Wanting to work in the electric vehicle segment, the group decided to start work on developing an electric three-wheeler instead.
Aside from regular funding from their sponsor, the team also received institutional support from IIT Kharagpur.
With a top speed of 55 kmph, the final Deshla prototype has a battery range of 150 km on a single charge. To achieve this battery range, they are using an 8.8 kilowatt-hour battery pack.
With the same battery pack capacity, I can actually run a motor which will be three-four times more powerful. Moreover, I can charge these batteries three-four times faster. As a consequence, we are installing more powerful motors than we typically use in an e-rickshaw. We have seen that these e-rickshaws typically use a 1 kw motor, but we are going with a 3.5 kw motor. Automatically, we can get better torque speed characteristics, says Professor Racherla, speaking to The Better India.
Typically, potential customers should be able to charge these batteries in four hours at home. In addition, the team is developing a passive thermal management system for their batteries (cooling the battery without using electricity). This will keep batteries below peak ambient temperature and increase their lifespan significantly.
In lithium batteries, a 10 degree Celsius drop in operating temperature can increase battery life by about three years—a huge value addition for the end user.
Nonetheless, the standout feature of the Deshla, which can carry three passengers and a driver (3+1) and six passengers (6+1), is the comfort it offers for both drivers and the passenger.
“Driving the Deshla must be effortless. In conventional auto rickshaws, they use handlebars for turning the wheel, similar to what you have in bicycles and bikes. This sort of steering causes a real problem on bad roads because the road can actually turn the handlebar. In other words, for the auto to move along a straight line, drivers will have to hold onto the steering with their strength. This takes up a lot of effort,” says Professor Racherla.
Instead, the Deshla contains a steering wheel and functions on gear mechanism with high mechanical advantage, claims Racherla. Instead of mechanical brakes, the vehicle uses hydraulic brakes for more effective braking. However, that’s not all.
Normally, the auto driver spends anywhere between 6-10 hours per day sitting in his vehicle. They should not feel any extreme loads or jerks while they are riding. We are focussing a lot on seat design and design the steering so that it’s effortless for the driver to ride, he says.
As for the passengers, Racherla explains that the current autos or the electric rickshaws use rigid axles and leaf springs, a system used in trucks where you’re unaware of the load you’ll be carrying and want to ensure that the system does not fail. But this way the passenger feels extreme jerks, particularly on bad roads.
So, the team has designed a vehicle with a suspension system similar to cars. They are using independent suspensions so that each wheel can move independently with respect to the other wheel. They are also using coil springs along with dampers. The combination of these two elements with a good seat design ensures a comfortable ride on bad roads. It also increases the stability of the vehicle.
For six passengers, the rickshaw can attain maximum speeds of 40 kmph.
Thus far, the team has conducted successful user trials, and developed the embedded and power electronics subsystems such as motor controller, battery charger, 3G cellular connectivity modules, GPS and a battery management system.
The next step for Professor Racherla and his team is to raise around Rs 3 crore of seed funding to make the final commercial product and get necessary certification from the Automotive Research Association of India (ARAI). For this process, Racherla and two students—Shyama Agrawal and Manuj Agrawal—who graduated in May 2018, but are still closely working on the product, set up a startup to raise the necessary funding.
“Depending on the funding we receive, and presuming things go well, we are looking at a year from now for the commercial vehicle to be developed and certified by ARAI. In a further 9-12 months, we expect the vehicle to start rolling out of our factory,” he claims.
(Edited by Saiqua Sultan)