Students are the future professionals of any industry, and events that ask for their creativity and innovation bring out the best of futuristic ideas. This reality holds true in the automotive sector, where the innovations of today could become the normal future of mobility. Shell organised its annual Eco-marathon competition that invites students to develop, design and build energy-efficient cars and pin them against other such competitors across the globe.
The RV College of Engineering (RVCE) in Bengaluru has been participating in the Shell Eco-marathon competition since 2010, through its Team Garuda. We spoke to the team’s current manager Bharath V as well as Gagan M, Electrical Head of Team Garuda to understand their entry for the 2019 edition of the competition.
Bharath said Garuda was one of the technical teams that was formed at RVCE in 2006 with a focus on sustainability and green mobility. The college has around 10-12 technical teams, with each having its own speciality. While Team Garuda was set up by students from the mechanical engineering branch, Bharath said the team now comprises students from all branches of engineering. Team Garuda gets most of its funding catered to by the college administration, but is always on the lookout for companies with a similar goal for sponsorships.
Team Garuda has been a repeat-participant at the Shell Eco-marathon since 2010, but a momentous milestone was achieved in 2017 when it became the first Indian team to switch to battery electric current concept vehicles. The team’s battery electric urban-concept car with which it participated in the 2019 edition of Shell Eco-marathon was christened ‘Mjolnir’ (lightning). The concept car uses indigenously-designed and constructed systems that are 60-70 % lighter than its predecessor. It uses an integrated motor controller with a Proportional-Integral-Derivative (PID) controller system.
MJOLNIR BATTERY ELECTRIC URBAN-CONCEPT CAR
The decision to move from petrol internal combustion engine-powered vehicle to a battery electric vehicle brought about a few challenges, noted Gagan. The key requirement from the Shell Eco-marathon competition was that a motor controller needed to be built by the team indigenously. The main function of the motor controller is to just take signals from the motor and get it running with the use of the battery. Gagan said this was a huge challenge for Team Garuda, since the team did not have the technical know-how of the technology.
After going through a range of content in the area of motor controllers, the team finally started experimenting on various circuits, and experience a number of failures on the way, said Gagan. However, he added that Team Garuda finally achieved the optimum setup that was working. This process of developing and testing the most apt motor controller has taken the team two years of continuous R&D, he noted.
Besides components like the motor controller, the team has also developed and designed a number of other parts for the vehicles in-house. These include the outer shell that is made of carbon fibre reinforced polymer composites (CFRP), aluminium chassis designing, steering design as well as assembly. Almost every aspect of the car is designed in-house by Team Garuda, with only a few parts being bought from out. The team also carries out finite element analysis on the body and chassis in order to have the least coefficient of drag, in addition to keeping the weight low.
The Mjolnir concept car weighs about 180 kg with a driver, and runs on a 20A rated 48 volt battery with inbuilt BMS. The motor in the car is of 1 kW rating, with an engine speed of about 3,000 rpm and a torque curve of 4.5 Nm that can go up to peak of 10 Nm. Team Garuda uses different converters for different voltages to make the setup highly efficient. The concept car features free-wheel drive mechanism like that found on bicycles, which is contrary to brake regeneration that is usually the case in electric vehicles. Gagan noted that this is an innovation pulled off by the team, which is claimed to be more efficient than regenerative braking.
Bharath said even though the technology is readily available online, there is a requirement to have a solid foundation of these technologies, which basically comes from reading books. The educational syllabus provides a strong foundation for students, but the rest is totally upon the students themselves on how they can convert the knowledge gained from books into something like the project achieved in the form of the Shell Eco-marathon, he added. In addition, Bharat said students from across the globe participating in the competition share ideas and insights with each other, thereby enabling a large-scale level of knowledge sharing, which provides food for future designs and developments.
In terms of Team Garuda’s participation in Shell Eco-Marathon Asia 2019, the team said it was a rollercoaster experience, especially with an initial setback being the delayed arrival of the car by two days. The car arrived on the penultimate day of the event, and the team got the car prepared in an hour and proceeded towards the technical inspection and cleared all the inspections on the same day. However, this led to the team not participating in the practice sessions to understand the track better, Team Garuda noted. In addition, the team did not have a battery to power the car, but camaraderie came in the form of a spare battery being offered by a competing team from Thailand. However, Team Garuda could not clock a valid run as the battery died during the last lap of the second run.
Team Garuda has participated in another edition of the Shell Eco-marathon, which did not turn out to its favour due to various causes. The team, however, is looking forward to the future edition of the competition. The upgrades that Team Garuda is looking at for the next iteration of its concept vehicle include the purchase of cells to build its own indigenous battery box as well as develop a custom BMS. With such a keen focus on further development and open learning from competitors, the team is expected to achieve greater heights in further competitions like the one it participated in.
TEXT: Naveen Arul