Determination of Optimal Gear Ratio of BAJA SAE All-Terrain Vehicle

The final drivetrain ratio is an essential part of a vehicle. It is responsible for providing the desired torque to overcome obstacles while maintaining the speed and acceleration of a vehicle. A vehicle must have an optimum gear ratio to obtain the desired velocity and acceleration. To achieve this, four different approaches were used considering the input parameters of a BAJA All-Terrain Vehicle (ATV). The traction received from the ground is calculated and plotted against velocity on different terrains. Further, a drivetrain was modeled in Simulink to obtain different parameters like vehicle speed, acceleration, and wheel slip. A range of gear ratios was obtained by following a similar trend of vehicle parameters that were best suited for improving vehicle performance. Graphs were plotted to compare the effect of various vehicle parameters, and an optimum gear ratio was obtained. Based on the obtained results, it can be concluded that a gear ratio ranging from 7.5 to 8.5 will provide the optimum ratio and exhibit a consistent trend of results.