SAE MiniBaja 2015 Powertrain
presentationposted on 05.05.2016, 00:00 by Gregory Brown, Logan Krier, Ethan Oberg, J. Forrest Schumacher
The SAE MiniBaja Series is an annual competition in which dozens of collegiate teams submit an off-road vehicle to compete in a number of challenges to demonstrate each team's ability to perform real-world engineering tasks. These competitions include the following: a hill climb test, endurance test, acceleration test, maneuverability test, and rock crawl test. The objectives of the powertrain team are to maximize the vehicles performance in each of these challenges. To accomplish these objectives, our team focused on improving low-end torque over previous years' designs, operating at the highest engine speed as much as possible in order to maximize power output, improving driving simplicity, as well as increasing maneuverability through the addition of driver-controlled forward, neutral, and reverse settings. These were achieved through the use of a continuously-variable transmission (CVT) and a forward-neutral-reverse (FNR) gear set. The CVT allows for an infinite range of gear ratios bounded by a high and low ratio which automatically adjusts to operate at a nearly constant engine speed. If calibrated correctly, the CVT allows the engine to constantly operate at its highest possible speed, maximizing power output. The FNR assists maneuverability by allowing the driver to select neutral and reverse settings if the vehicle has trouble navigating any terrain.