We designed and optimized a shoebox-sized autonomous vehicle for the American Institute of Chemical Engineers (AIChE) ChemE Car Competition, where cars must travel a specified distance and stop precisely using only chemical reactions for propulsion and control. Our project integrated reaction kinetics, heat and mass transfer, process design, electrical systems, and programming while meeting safety, environmental, and competition constraints.
We utilized thermoelectric generators (TEGs) operating via the Seebeck effect for propulsion. We created a temperature gradient between an exothermic acid-base reaction on the hot side and a cold reactor containing frozen aqueous ethylene glycol mixture. We performed energy and mass balances to predict heat transfer and electrical output, ensuring sufficient voltage to drive the motor.
Our stopping mechanism relied on an iodine clock reaction, where a distinct color change occurred once thiosulfate was depleted. A photosensor connected to an Arduino detected this color change and immediately ceased power to the motor, stopping the vehicle. By varying reactant concentrations, we altered reaction time and precisely controlled stopping distance. We developed calibration curves correlating reaction time with reactant concentrations, enabling accurate distance prediction on competition day.
Through extensive testing and documentation, we identified the most consistent operating conditions. Our project resulted in a fully autonomous ChemE Car capable of operating without external intervention, demonstrating practical application of chemical engineering concepts and competing at the AIChE Regional Student Conference.