Battery-free TPMS – SRI reports on research partnership

Sumitomo Rubber Industries, Ltd. (SRI) is collaborating on a project to eliminate batteries in TPMS and similar devices by replacing these with electricity generated through tyre rotation. Reporting on the progress of its work with Professor Hiroshi Tani of Kansai University in Japan, the Falken brand manufacturer says the partners have successfully generated stable electricity over a wide range of speeds by employing two types of generating devices.

To generate electricity at low speeds, the partners turned to a device that utilises the tension caused by changes in tyre strain. At higher speeds, they employed a device that generates power from the centrifugal force caused by changes in acceleration. By connecting both types of generation mechanisms in parallel, the partners obtained stable power over a wide range of speeds. They later confirmed these results by powering an in-tyre TPMS unit during on-road testing.

One of the devices uses tension caused by changes in tyre strain to generate electricity, the other the centrifugal force caused by changes in acceleration (Source: SRI)

By combining both devices, sufficient energy is available to power TPMS at various speeds (Source: SRI)

Solution to a critical problem

“The Sumitomo Rubber Group is actively engaged in wide-ranging research and development as part of our Smart Tyre Concept, a forward-thinking concept for the development of new technologies for tyres and peripheral services, through which we aim to better respond to the needs of CASE, MaaS and other major new innovations that are already transforming the automotive industry,” states SRI. “We believe that this tyre internal power generation technology is a solution to the most critical problem in tyre sensing, which is the battery life of the sensor device, and that its realisation will greatly advance the practical application of tyre sensing.”

According to SRI, a grant from the New Energy and Industrial Technology Development Organization (NEDO) made this achievement possible. It now aims to further accelerate the technology’s development.