Integrated Sensor for Distributed Monitoring of Wheel Rim Temperature in Gran Turismo Cars

This paper introduces the design, characterization, and integration of an innovative temperature sensor prototype aimed at continuously monitoring the wheel rims made of composite materials used in Gran Turismo cars. The system monitors real-time temperature across multiple points on the wheel rim's surface, triggering alarms when critical thresholds are reached, which could compromise the material's chemical and physical properties. Unlike existing commercial solutions that use externally mounted infrared sensors or those integrated into tire pressure sensors, this prototype is fully integrated into the wheel without the need for external devices and directly measures the wheel rim's temperature. Operating conditions posed significant design challenges, including temperatures up to $250{}^{\circ} \mathrm{C}$, high accelerations, and tight spatial constraints. The prototype is made of a flexible circuit adapting to the wheel rim's circular shape, and it consists of a back-end for data processing and wireless communication, temperature probes, and a signalconditioning front-end. Communication is achieved via Bluetooth Low Energy (BLE), ensuring low power consumption. The prototype underwent three testing phases: laboratory functional testing, performance analysis, and on-track tests with the sensor integrated into a wheel rim installed on a Gran Turismo car. Laboratory results demonstrated high measurement accuracy and quick response to temperature changes, and on-track tests proved the robustness of the sensor while revealing limitations in wireless communication due to electromagnetic shielding from the tire's metal parts and vehicle structure.