College racing competitions are a very important aspect of learning for the undergraduate engineering students as it provides a platform to put theoretical knowledge to a test in the real world. Mahindra BAJA SAE is one of the few platforms where students come around with their builds and test in the competition. The event is organized globally by the Society of Automotive Engineers, USA. The event originated in the name of Mini - BAJA, in the year 1976 at the University of Carolina. Since then, the event has spanned six countries – the USA, Mexico, South Africa, Korea, Brazil, and India. The event requires the students to design, fabricate and validate an off-road vehicle to take part in series of events that are spread over a course of 3 days that test the vehicle for the engineering practices that have gone into it. The vehicles are tested in terms of gradability, speed, acceleration, and maneuverability characteristics, and durability.
Founded in 2006, Team Kshatriya is a prominent team in Mahindra BAJA SAE and was ranked third consecutively for the fourth year in the competition. The Kshatriyas come from the prestigious Vellore Institute of Technology (VIT) to take part in the grueling event held at the Natrax testing facility at Pithampur, near Indore. The event follows a strict set of rules for the off-road builds and all cars must adhere to these. The prototypes should be made within the specified dimensions as per the rule book and should achieve a top speed of 35 km/h in a certain distance to pass the acceleration test. The buggy should pass the safety test which requires the driver to move out of the car in under 5 seconds in which the driver has to press the engine kill switch and unbuckle his seat belt. When undergoing the braking test, all four wheels of the buggy should lock-up under hard braking. These are a few of the rules for the cars to follow to enter into the race. But, for the year 2021, a new instruction has come in from the competition that all cars featuring a 4WD in 2021 and 2022 will be rewarded additional points, with an all-wheel-drive (AWD) / four-wheel-drive (4WD) system must from 2023 onwards.
Team Kshatriya have already started their rituals for 2021 and are determined to grab a podium finish again for the next year. Preparations for the AWD system are in full force and here’s how they have lined up to improve their winning recipe for next year’s competition.
Tweaks For Team Kshatriya's Chariot :
For the first time since the team’s inception, they are working on a four-wheel-drive system. The team has started from scratch but cannot fully troubleshoot their problems due to the Coronavirus pandemic. The general strategy to improve their previous design has taken a setback as the new four-wheel-drive setup is completely new. Physical testing has come to a halt as none of the colleges in India is open and has forced the team to find an alternative approach to quantify their new setup. The buggy will also feature AFCO coil-over shocks to endure the punishing terrain at the event.
Four-Wheel Drive Systems :
In the previous iteration of their rear-wheel-drive cars, the engine power was transmitted to the rear tyres via a CVT connected to 2 stage gearbox and finally to tyres through UV shafts. But, in the new layout, the power is distributed in the gearbox itself to the front differential. A propeller shaft has also been added as a driveline between the rear and front. For better articulation angle that aids in maneuverability, front tyres are connected to the differential via CV shafts. The cherry on top is a new shifting mechanism between the propeller shaft and front differential to change from 4WD to 2WD and vice-versa whenever required.
Implications of Building a 4WD System :
The new system has added more weight to the build due to the increase in the number of components. The increase in weight of the car in addition to the same power output from the previous-gen engine has decreased the power-to-weight ratio of the car and this will prove to be a downside for the team. Even with a reduced power-to-weight ratio, the Kshatriya’s have the same ideology to try and build the best ATV possible. Their target is to win the competition and design a car that is the best in terms of track performance as well as the lowest possible manufacturing costs.