Electrical power generated by tires

Devices requiring “trickle power,” such as tire pressure sensors, could in future be charged by kinetic electricity generated inside the tire.

In its media release introducing the “Energy Harvester” technology Japanese company Sumito Rubber Industries (SRI) stated: “we are confident that the results of this latest research will lead to practical applications for this new technology as a power source for sensors used in TPMS (Tire Pressure Monitoring System) and other automotive devices, contributing to the creation of future services that make use of various digital tools without any need for batteries. The Energy Harvester is contained in a small box placed inside the tire. It forms part of SRI’s “Smart Tire Concept,” a tire technology development concept that aims to achieve “even greater safety environmental performance,” says the company. The Japan Science and Technology Agency recently selected the Energy Harvester project for additional research.

Automotive Industries (AI) asked Dr Bernd Löwenhaupt, Managing Director, Sumitomo Rubber Europe, how the technology was developed. Löwenhaupt: Sumitomo Rubber Industries, Falken’s parent company together with Professor Hiroshi Tani of Kansai University in Japan, developed the Energy Harvester. This new technology takes advantage of the build-up of static electricity, known as frictional charging, to produce power efficiently as the tire turns. It could see tires generate electricity whilst driving.

AI: How does the Energy Harvester work? Löwenhaupt: Inside the Energy Harvester are two layers of rubber each covered in an electrode, along with a negatively charged film that interfaces with a positively charged film. When fixed to the inside of a conventional tire carcass it generates electricity as the tire deforms during rotation.

AI: Which devices and sensors can be powered by the Energy harvester? Löwenhaupt: We believe the Energy Harvester could lead to practical applications as a power source for sensors used in TPMS (tire pressure monitoring systems) and other automotive devices without the need for batteries.

AI: How does your advanced 4D-Nano Design technology enable savings in fuel consumption and at the same time improve the tire’s performance in wet conditions? Löwenhaupt: Low rolling resistance, outstanding safety and durability are the three main requirements that car tires need to fulfil, both today and in the future. To drive progress in this area, our scientists and engineers at Sumitomo Rubber Industries conducted pioneering research into the molecular structure of tires, using particle accelerators and advanced computer simulation. They succeeded in simulating and controlling the molecular structure of rubber compounds used for tires at nano level. For example, we analyzed where and how superfluous heat was generated in the tire and how this development could be minimized. Heat means loss of energy for the tire, and thus rolling resistance – which is ultimately responsible for fuel consumption. Advanced 4D-Nano Design technology found in all of our new tires is the result of these advanced findings in molecular structures. It enables savings in fuel consumption of up to 5% to be achieved compared to conventional tire models, and significantly improves the tire’s performance in wet conditions. It has also led to us achieving some impressive results in independent tire tests in Europe.

AI: Can the Falken Gyroblade airless tire replace conventional air-filled tires? Löwenhaupt: Wouldn’t it be great if flat tires were a thing of the past? This all-new airless tire technology could banish not only flat tires but also the laborious processes of tire inflation and pressure monitoring. Some car manufacturers are testing the technology and we continue to refine this concept. We believe it will be a good concept for the conventional tire in applications where convenience is key.

AI: Is Sumitomo Rubber Industries committed to improving global environmental protection in tire production, and what environmentally compatible methods do you employ to manufacture products that are both sustainable and at the forefront of technology? Löwenhaupt: We have 12 plants worldwide, and their sustainability and environmental conditions are very important. Sumitomo Rubber Industries is committed to improving global environmental protection in tire production. The core topics involved in the issue are fuel savings, use of sustainable raw materials and careful husbanding of resources. Under these watchwords, SRI continuously analyses and optimizes the manufacturing processes and components used to produce Falken tires. This includes the NEO-T01 process that enables us to produce more consistent tires that consequently use less material. Another key part of the company’s activities in this respect comprises advanced research into biosynthetic mechanisms that extends into the nanostructure level of the tire’s structure. This research is making it possible to produce natural rubber using environmentally compatible methods, and thus manufacture products that are both sustainable and at the forefront of technology.

AI: What can we expect from Sumitomo and Falken? Löwenhaupt: We are developing a new patent for summer and winter tire with a low rolling resistance. We are also developing specific tires for electric and hybrid vehicles. For conventional cars the most important factor is the rolling resistance, because of the penalties coming in 2021. For electric and hybrid vehicles, minimizing rolling resistance in order to reduce CO2 s is not as critical, but mileage or range is very important. Therefore, everybody is asking for ‘A’ label tires. It is the same for tire wear, of course. A combination of high power and inertia due to the weight of battery packs in electric vehicles reduces the life of tires significantly. We have to reduce the rolling resistance but we have to balance this with compounds that give motorists the same mileage as they get with conventional cars.