https://www.epo.org/en/news-events/press-centre/press-release/2018/452041

Regenerative tyres with a longer, greener life: Agnès Poulbot and Jacques Barraud† named European Inventor Award 2018 finalists

24.04.2018

in Press release

French researchers Agnès Poulbot and Jacques Barraud nominated for European Patent Office (EPO) prize for self-regenerating tyre tread technology
Obtained through 3D printing, their tread design enhances the performance of used tyres throughout their lifespan and in all seasons, while significantly decreasing fuel consumption and CO₂ emissions
EPO President Battistelli: "Balancing transportation demands and the burden on the environment is a major challenge. Poulbot and Barraud 's innovative technology has the potential to boost sustainable mobility."

Munich, 24 April 2018 - Our combustion-engine vehicles, while necessary for moving people and goods from place to place, emit large amounts of pollutants with serious environmental and health-related consequences. Cars, lorries and other vehicles are responsible for at least 20% of the world's human-made CO₂ emissions, not to mention the potentially harmful mono-nitrogen oxides and fine particulates their engines spew out. A host of innovations from electric motors and alternative fuels to driverless vehicles might one day help significantly reduce transportation-related pollutants, but an invention from French researchers Agnès Poulbot and Jacques Barraud could make curbing CO₂ and other emissions as simple as changing our vehicles' tyres. They have created a patented tread design that enables heavy-duty vehicle tyres to regenerate as they are used, while ensuring the same performance and grip throughout their lifespan. The design not only increases durability, it reduces fuel consumption and associated CO₂ emissions.

For this achievement, Agnès Poulbot and Jacques Barraud have been nominated as finalists for the European Inventor Award 2018 in the "Industry" category. The winners of this year's edition of the EPO's annual innovation prize will be announced at a ceremony in Paris, Saint-Germain-en-Laye, on 7 June 2018.

"Managing transportation demands and the burden on the environment is a major challenge. Poulbot and Barraud's technology has the potential to boost sustainable mobility," said EPO President Benoît Battistelli announcing the European Inventor Award 2018 finalists. "Innovation often involves looking at familiar problems from a new viewpoint, and this is precisely what these two inventors have done."

An unconventional approach

Agnès Poulbot, a mathematician and expert in 3-D modelling working at Michelin's Innovation Centre, did not re-invent the wheel. She did, however, re-think the tyre. Instead of following the classical approach in her industry to mould tyres with a single-layer tread design made with a specific pattern and depth, Poulbot looked deeper into the tyre itself.

She came upon the idea when talking to a client, the owner of a long-haul transport firm, who wondered why partially worn tyres were more energy-efficient than newer ones. An example of this can be found in the racing slicks used in motor racing that are designed to maximise traction and minimise rolling resistance through their smooth surface. The problem with these types of tyres is that as soon as it starts to rain, they lose a considerable amount of traction. An accumulation of water between the tyre and road surface can lead to aquaplaning - an unsettling and dangerous loss of control for the driver.

Poulbot explained to her customer that there was a trade-off between deeper treads to channel away water from the road surface and shallow treads that resulted in less rolling resistance: "The deeper grooves of new tyres [necessary to lead water away from the tyre in wet conditions] are more prone to flexing and deforming, which increases the rolling resistance of the tyre. When these grooves are worn down through use, the body of the tread flexes less and the performance improves."

"But that got me thinking," she continues. "What if I could design a tyre with multiple shallow treads, stacked on top of each other?"

The result, after careful calculation and painstaking computer modelling, was a tyre design based on a vertically-layered collection of tread patterns within each tyre. When the tyres are first mounted, only the first traction layer is visible. Over time, the layer wears away to reveal a new, hidden tread - specially positioned ridges and grooves - from underneath. This second layer also wears away in time, and a third appears. Essentially, the tyre "self-regenerates" as it wears down, The tyre tread is optimised for minimal energy dissipation and reduced rolling resistance in order to secure the best possible performance during its lifetime.

An unconventional design, however, also required an unconventional means of production. Together with Jacques Barraud, who before passing away in 2016 worked at Michelin as a senior expert in tyre design and production for heavy vehicles, Agnès Poulbot created a special mould to create the tread patterns in three dimensions and enable production on a scale large enough for fleet after fleet of heavy-duty vehicles.

Multiple layers for a triple-A rating

Reduced rolling resistance and increased fuel efficiency offered by Poulbot and Barraud's regenerating-tread tyres are not the only benefits. This fuel efficiency also corresponds to a significant reduction in vehicle emissions. The European Commission estimates that heavy-duty vehicles alone produce around one quarter of CO₂ emissions from road transport and around 5% of the EU's total greenhouse gas emissions. In total, Europe's cars, buses, vans and lorries are responsible for about 20% of the region's total human-made CO₂ emissions -largely in line with global averages.

Using tyres with lower rolling resistance is one way to reduce emissions, which is why in 2012 the EU began putting pressure on the automotive industry through the introduction of tyre labels. According to Michelin, the regenerative tread design, marketed as Regenion^TM technology, results in 3 724 kg fewer CO₂ emissions over the lifespan of a set of tyres than its predecessors. To put this in perspective, Agnès Poulbot says that if all Michelin PL tyres in Europe were equipped with her tyre tread design, this could result in annual CO2savingsroughly equivalent to the amount of CO₂produced by the city of Paris in one month. The company also calculates that by achieving a respectively higher mileage through the self-regenerating tread concept, lorry fleet operators can expect a 15 to 20% increase in tyre lifespan.

The tyre tread design was commercialised in different tyre product lines for heavy vehicles in 2013 and for passenger cars starting in 2016. All models have received the EU's AAA tyre label rating, ensuring they have the highest-rated fuel efficiency and shortest braking distance under wet conditions. In addition, the tyres help reduce noise pollution by producing less rolling noise than required by 2016 regulations.

Rising market demand for green innovation

While tyre design and materials science might not attract the same attention as other types of transportation advances, it is actually an active area for development. Poulbot and Barraud's patent adds to an already large intellectual property portfolio at Michelin that regularly places the company as one of the top French applicants for European patents and as a leading patent applicant in the transportation sector. This legacy of investment in research and development, which extends back to its first patent in 1891, has helped Michelin grow to become one of the biggest tyre manufacturers worldwide.

Reports show the French tyre maker has some 170 000 tyre units incorporating Poulbot and Barraud's invention in 2017. The company forecasts that it will sell a total of 670 000 PL units by 2019, which would amount to 15% of its total sales of heavy-duty tyres. By 2022, Michelin expects 30% of the heavy-duty tyres it sells will incorporate the technology.

The latest report from Smithers Rapra estimates that the market for truck tyres stands at around EUR 91 billion, with an expected growth rate of around 3.5% per year for the coming decade. The market intelligence firm says that the demand for greener tyres will continue to grow because of increasing regulations and pressure from car manufacturers.

A passion for puzzles

Agnès Poulbot was born in Paris in 1967 and studied mathematics and computing sciences in Grenoble. After receiving her PhD in applied mathematics from the University of Grenoble in 1993, Poulbot joined the CEA (Atomic Energy Commission) where she contributed to the development of an image reconstruction algorithm for use in medical tomography. She started work at Michelin in 1996, where she now holds the position of Senior Expert in Pre-Development and Advanced Research for Truck and Bus Tyre Design for the European Market. A mother of five children, she loves solving logic puzzles with her family.

Jacques Barraud was born in 1958 in Cholet in the west of France. He joined Michelin in 1979 and worked as an engineer, trainer and project leader before he passed away in 2016. When Poulbot started working at Michelin in 1996, he accompanied her through training. The two worked together on their self-regenerating tyre tread design for four years and frequently went out jogging together in Clermont-Ferrand, where Michelin's Innovation Centre is located.

Additional resources

Downl oad our app " Innovation TV " to your smart TV and watch video portraits of all finalists on your TV screen.

View the patent: EP2379352

The power of maths for innovation

A growing number of inventions rely on complex mathematics. Key examples from previous editions of the European Inventor Award include the multinational team who designed the complex signal modulation techniques that enable the next-generation satellite navigation system "Galileo". Their work won them the Award in the category "Research" last year. Other Award finalists and winners whose inventions rely on serious number crunching include Joan Daemen and Pierre-Yvan Liardet's cryptographic techniques that help keep bank cards safe (2016 finalist in the "Industry" category) and Carles Puente's fractal-base antennae that helps make the mobile internet possible (2014 finalist in the "SMEs" category).