Energy Harvesting for Tire Pressure Monitoring Systems: Design Considerations

As of September 2007, all cars sold in the United States must be equipped with a Tire Pressure Monitoring System (TPMS). Pending legislation in the European Union and some Asian countries makes universal adoption likely in many parts of the world. Given this large mandated market along with the fact that current TPMS modules require a battery for operation, interest in energy harvesters for TPMS is high. All TPMS modules currently on the market attach to the rim or valve stem rather than the tire. The focus of this paper is to explore the application requirements, feasibility, and design considerations for rim and valve stem based energy harvesters to replace the battery in TPMS modules. The energy input along with the application requirements make a MEMS based design highly impractical. However, a technical solution to the problem that meets the current requirements from the energy available is feasible if difficult considering some of the extreme requirements.